The document proposes a load-aware routing scheme for wireless mesh networks to balance traffic load and enhance network capacity. It divides the network into clusters, with each cluster head estimating traffic load and increasing routing metrics for overloaded links. This causes users to route around overloaded areas, achieving overall load balancing in a distributed manner. Simulation results show the proposed scheme outperforms routing using expected transmission time as a metric.
Efficient Load Balancing Routing in Wireless Mesh Networksijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
ENERGY EFFICIENT NODE RANK-BASED ROUTING ALGORITHM IN MOBILE AD-HOC NETWORKSIJCNCJournal
Mobile Ad-hoc Network (MANET) is an emerging technology, infrastructure less with self-organizing, selfhealing, multi-hop wireless routing networks in real time. In such networks, many routing problems arise due to complexity in the network mobility which results from difficulty in achieving energy efficient routing
in the field of MANET. Due to the dynamic nature and the limited battery energy of the mobile nodes, the communication links between intermediate relay nodes may fail frequently, thus affecting the routing performance of the network and also the availability of the nodes. Though existing protocols are not
concentrating about communication links and battery energy, node links are very important factor for improving quality of routing protocols because Node Rank helps us to determine whether the node is within transmission range or out of transmission range through considering residual energy of the node during the routing process. This paper proposes a novel Energy Efficient Node Rank-based Routing (EENRR)
algorithm which includes certain performance metrics such as control overhead and residual energy in order to improve the Packet Delivery Ratio (PDR), and Network Life Time (NLT) from its originally observed routing performance obtained through other existing protocols. Simulation results show that, when the number of nodes increases from 10 to 100 nodes, EENRR algorithm increases the average residual energy by 31.08% and 21.26% over the existing Dynamic Source Routing (DSR) and Energy Efficient Delay Time Routing (EEDTR) protocols, respectively. Similarly it increases the PDR by 45.38% and 28.3% over the existing DSR and EEDTR protocols respectively.
ENERGY EFFICIENT MULTICAST ROUTING IN MANET ijac journal
In this paper, we have presented the Modified Multicasting through Time Reservation using Adaptive
Control for Excellent Energy efficiency (MMC-TRACE). It is a real time multicasting architecture for
Mobile Ad-Hoc networks to make their work an energy efficient one .MMC-TRACE is a cross layer design
where the network layer and medium access control layer functionality are done in a single integrated
layer design. The basic design of the architecture is to establish and maintain an active multicast tree
surrounded by a passive mesh within a mobile ad hoc network. Energy efficiency is maximized by enabling
the particular node from sleep to awake mode while the remaining nodes of the same path are maintained
at sleep mode. Energy efficiency too achieved by eliminating most of the redundant data receptions across
nodes. The performance of MMC-TRACE are evaluated with the help of ns-2 simulations and comparisons
are made with its predecessor such as MC-TRACE. The results show that the MMC-TRACE provides
superior energy efficiency, competitive QoS performance and bandwidth efficiency.
DYNAMIC CURATIVE MECHANISM FOR GEOGRAPHIC ROUTING IN WIRELESS MULTIMEDIA SENS...csandit
Maintaining network stability and extending network lifetime to cope with breaking links and topology changes remain nowadays a unsolved issues in Wireless Multimedia Sensor Networks (WMSNs), which aim to ensure flow delivery while guaranteeing QoS requirements, particularly, during data transmission phase. Therefore, in this paper, we jointly consider multipath transmission, load balancing and fault tolerance, to enhance the reliability of transmitted data. We propose a Dynamic Curative Mechanism for Geographic Routing in WMSNs. Theoricals results and those obtained from simulation study demonstrate the validity and efficiency of our proposed mechanism, and indicate that it is highly advised for multimedia transmission and network stability
Packet Transfer Rate & Robust Throughput for Mobile Adhoc NetworkEswar Publications
An ad-hoc wireless network is highly different considering dynamic stochastic process of its underlying links, leads to link breaks during data transaction. Hence, to provide free flow data transaction, many routing algorithms have the property of link recovery and maintenance procedures to minimize the loss of data during transmission. However these routing method do not guarantee reliable data transmission in some special application conditions with wide requirements on Packet delivery ratio and link quality of the network. Routing is a critical issue in MANET and hence the focus of this paper is the performance analysis of different routing protocols used in the
wireless network. We evaluate the ability of a mobile ad hoc wireless network to distribute flows across robust routes by introducing the robust throughput measure as a performance metric. The utility gained by the delivery of flow messages is based on the level of interruption experienced by the underlying transaction. We describe the mathematical calculation of a network’s robust throughput measure, as well as its robust throughput capacity. We introduce the robust flow admission and routing algorithm (RFAR) to provide for the timely and robust transport of flow transactions across mobile ad hoc wireless systems.
Hierarchical Genetic Algorithm For Dynamic Channel Units Allocation in TD-CDM...ijwmn
Hierarchical Genetic Algorithms (HGA) as a tool for search and optimizing methodology have now reached a mature stage. The minimum resource facility to carry user traffic, termed a channel unit (CU), is composed of a one time-slot and one code in the TD-CDMA/TDD system. The control of the number of CUs depends on the traffic load solves varied and asymmetrical traffic problems in the 3G system. In a cellular network, the call arrival rate, call duration and the communication overhead between the base stations and the control center are vague and uncertain, regardless of whether the criteria of concern are nonlinear, constrained, discrete or NP hard. In this paper, the HGA is used to tackle the neural network (NN) topology as well as the fuzzy logic controller for the dynamic CU allocation scheme in wireless cellular networks. Therefore, we propose a new efficient HGA CUs Allocation (HGACA) in cellular networks. It aims to efficiently satisfy the diverse quality-of-service (QoS) requirements of multimedia traffic. The results show our algorithm has a lower blocking rate, lower dropping rate, less update overhead, and shorter channel-acquisition delay than previous methods
A MIN-MAX SCHEDULING LOAD BALANCED APPROACH TO ENHANCE ENERGY EFFICIENCY AND ...IJCNCJournal
Energy efficiency and traffic management in Mobile Ad hoc Networks (MANETs) is a complex process due
to the self-organizing nature of the nodes. Quality of service (QoS) of the network is achieved by
addressing the issues concerned with load handling and energy conservation. This manuscript proposes a
min-max scheduling (M2S) algorithm for energy efficiency and load balancing (LB) in MANETs. The
algorithm operates in two phases: neighbor selection and load balancing. In state selection, the
transmission of the node is altered based on its energy and packet delivery factor. In the load balancing
phase, the selected nodes are induced by queuing and scheduling the process to improve the rate of load
dissemination. The different processes are intended to improve the packet delivery factor (PDF) by
selecting appropriate node transmission states. The transmission states of the nodes are classified through
periodic remaining energy update; the queuing and scheduling process is dynamically adjusted with energy
consideration. A weight-based normalized function eases neighbor selection by determining the most
precise neighbor that satisfies transmission and energy constraints. The results of the proposed M2SLB
(Min-Max Scheduling Load Balancing) proves the consistency of the proposed algorithm by improving the
network throughput, packet delivery ratio and minimizing delay and packet loss by retaining higher
remaining energy.
The congestion control within the TCP (Transmission Control Protocol) plays a critical role in
amending data rate to evade congestion from happening possibilities. Based on TCP communication sender
not only guarantees the successful packet delivery, but also maintains the correct sequence of packets by
receiving the frequent acknowledgement from the receiver. In this research we proposed a congestion
control scheme with modified TCP and queue length variation with OLSR routing protocol in MANET. The
TCP protocol performance is modified by forwarding busy channel signals to predecessor nodes through
intermediate nodes in network. The congestion is controlled by that novel method of detecting the node is
busy or ready for communication. If the communication is start in network and the possibility if congestion
is arise, then in that case the queue length is handle the possibility of congestion. The congestion is
minimized due to awaring about the channel busy status and nodes buffer status or queue status. The TCP
protocol is able to handle the congestion situation but i.e. completely based on acknowledgement of receiver
and also not very effective to control it. The proposed TCP congestion control OLSR routing is improves
the network performance by reducing packet loss. The performance of network is measure through
performance metrics like throughput, PDF and Routing overhead in different node density scenarios. The
performance of proposed scheme is provides the better results.
Efficient Load Balancing Routing in Wireless Mesh Networksijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
ENERGY EFFICIENT NODE RANK-BASED ROUTING ALGORITHM IN MOBILE AD-HOC NETWORKSIJCNCJournal
Mobile Ad-hoc Network (MANET) is an emerging technology, infrastructure less with self-organizing, selfhealing, multi-hop wireless routing networks in real time. In such networks, many routing problems arise due to complexity in the network mobility which results from difficulty in achieving energy efficient routing
in the field of MANET. Due to the dynamic nature and the limited battery energy of the mobile nodes, the communication links between intermediate relay nodes may fail frequently, thus affecting the routing performance of the network and also the availability of the nodes. Though existing protocols are not
concentrating about communication links and battery energy, node links are very important factor for improving quality of routing protocols because Node Rank helps us to determine whether the node is within transmission range or out of transmission range through considering residual energy of the node during the routing process. This paper proposes a novel Energy Efficient Node Rank-based Routing (EENRR)
algorithm which includes certain performance metrics such as control overhead and residual energy in order to improve the Packet Delivery Ratio (PDR), and Network Life Time (NLT) from its originally observed routing performance obtained through other existing protocols. Simulation results show that, when the number of nodes increases from 10 to 100 nodes, EENRR algorithm increases the average residual energy by 31.08% and 21.26% over the existing Dynamic Source Routing (DSR) and Energy Efficient Delay Time Routing (EEDTR) protocols, respectively. Similarly it increases the PDR by 45.38% and 28.3% over the existing DSR and EEDTR protocols respectively.
ENERGY EFFICIENT MULTICAST ROUTING IN MANET ijac journal
In this paper, we have presented the Modified Multicasting through Time Reservation using Adaptive
Control for Excellent Energy efficiency (MMC-TRACE). It is a real time multicasting architecture for
Mobile Ad-Hoc networks to make their work an energy efficient one .MMC-TRACE is a cross layer design
where the network layer and medium access control layer functionality are done in a single integrated
layer design. The basic design of the architecture is to establish and maintain an active multicast tree
surrounded by a passive mesh within a mobile ad hoc network. Energy efficiency is maximized by enabling
the particular node from sleep to awake mode while the remaining nodes of the same path are maintained
at sleep mode. Energy efficiency too achieved by eliminating most of the redundant data receptions across
nodes. The performance of MMC-TRACE are evaluated with the help of ns-2 simulations and comparisons
are made with its predecessor such as MC-TRACE. The results show that the MMC-TRACE provides
superior energy efficiency, competitive QoS performance and bandwidth efficiency.
DYNAMIC CURATIVE MECHANISM FOR GEOGRAPHIC ROUTING IN WIRELESS MULTIMEDIA SENS...csandit
Maintaining network stability and extending network lifetime to cope with breaking links and topology changes remain nowadays a unsolved issues in Wireless Multimedia Sensor Networks (WMSNs), which aim to ensure flow delivery while guaranteeing QoS requirements, particularly, during data transmission phase. Therefore, in this paper, we jointly consider multipath transmission, load balancing and fault tolerance, to enhance the reliability of transmitted data. We propose a Dynamic Curative Mechanism for Geographic Routing in WMSNs. Theoricals results and those obtained from simulation study demonstrate the validity and efficiency of our proposed mechanism, and indicate that it is highly advised for multimedia transmission and network stability
Packet Transfer Rate & Robust Throughput for Mobile Adhoc NetworkEswar Publications
An ad-hoc wireless network is highly different considering dynamic stochastic process of its underlying links, leads to link breaks during data transaction. Hence, to provide free flow data transaction, many routing algorithms have the property of link recovery and maintenance procedures to minimize the loss of data during transmission. However these routing method do not guarantee reliable data transmission in some special application conditions with wide requirements on Packet delivery ratio and link quality of the network. Routing is a critical issue in MANET and hence the focus of this paper is the performance analysis of different routing protocols used in the
wireless network. We evaluate the ability of a mobile ad hoc wireless network to distribute flows across robust routes by introducing the robust throughput measure as a performance metric. The utility gained by the delivery of flow messages is based on the level of interruption experienced by the underlying transaction. We describe the mathematical calculation of a network’s robust throughput measure, as well as its robust throughput capacity. We introduce the robust flow admission and routing algorithm (RFAR) to provide for the timely and robust transport of flow transactions across mobile ad hoc wireless systems.
Hierarchical Genetic Algorithm For Dynamic Channel Units Allocation in TD-CDM...ijwmn
Hierarchical Genetic Algorithms (HGA) as a tool for search and optimizing methodology have now reached a mature stage. The minimum resource facility to carry user traffic, termed a channel unit (CU), is composed of a one time-slot and one code in the TD-CDMA/TDD system. The control of the number of CUs depends on the traffic load solves varied and asymmetrical traffic problems in the 3G system. In a cellular network, the call arrival rate, call duration and the communication overhead between the base stations and the control center are vague and uncertain, regardless of whether the criteria of concern are nonlinear, constrained, discrete or NP hard. In this paper, the HGA is used to tackle the neural network (NN) topology as well as the fuzzy logic controller for the dynamic CU allocation scheme in wireless cellular networks. Therefore, we propose a new efficient HGA CUs Allocation (HGACA) in cellular networks. It aims to efficiently satisfy the diverse quality-of-service (QoS) requirements of multimedia traffic. The results show our algorithm has a lower blocking rate, lower dropping rate, less update overhead, and shorter channel-acquisition delay than previous methods
A MIN-MAX SCHEDULING LOAD BALANCED APPROACH TO ENHANCE ENERGY EFFICIENCY AND ...IJCNCJournal
Energy efficiency and traffic management in Mobile Ad hoc Networks (MANETs) is a complex process due
to the self-organizing nature of the nodes. Quality of service (QoS) of the network is achieved by
addressing the issues concerned with load handling and energy conservation. This manuscript proposes a
min-max scheduling (M2S) algorithm for energy efficiency and load balancing (LB) in MANETs. The
algorithm operates in two phases: neighbor selection and load balancing. In state selection, the
transmission of the node is altered based on its energy and packet delivery factor. In the load balancing
phase, the selected nodes are induced by queuing and scheduling the process to improve the rate of load
dissemination. The different processes are intended to improve the packet delivery factor (PDF) by
selecting appropriate node transmission states. The transmission states of the nodes are classified through
periodic remaining energy update; the queuing and scheduling process is dynamically adjusted with energy
consideration. A weight-based normalized function eases neighbor selection by determining the most
precise neighbor that satisfies transmission and energy constraints. The results of the proposed M2SLB
(Min-Max Scheduling Load Balancing) proves the consistency of the proposed algorithm by improving the
network throughput, packet delivery ratio and minimizing delay and packet loss by retaining higher
remaining energy.
The congestion control within the TCP (Transmission Control Protocol) plays a critical role in
amending data rate to evade congestion from happening possibilities. Based on TCP communication sender
not only guarantees the successful packet delivery, but also maintains the correct sequence of packets by
receiving the frequent acknowledgement from the receiver. In this research we proposed a congestion
control scheme with modified TCP and queue length variation with OLSR routing protocol in MANET. The
TCP protocol performance is modified by forwarding busy channel signals to predecessor nodes through
intermediate nodes in network. The congestion is controlled by that novel method of detecting the node is
busy or ready for communication. If the communication is start in network and the possibility if congestion
is arise, then in that case the queue length is handle the possibility of congestion. The congestion is
minimized due to awaring about the channel busy status and nodes buffer status or queue status. The TCP
protocol is able to handle the congestion situation but i.e. completely based on acknowledgement of receiver
and also not very effective to control it. The proposed TCP congestion control OLSR routing is improves
the network performance by reducing packet loss. The performance of network is measure through
performance metrics like throughput, PDF and Routing overhead in different node density scenarios. The
performance of proposed scheme is provides the better results.
Energy efficiency cross layer protocol for wireless mesh networkIJCNCJournal
Wireless mesh network (WMN) is a novel emerging tec
hnology that will change the world more effectively
and efficiently. It is regarded as a highly promisi
ng technology being increasingly important in mobil
e
wireless networks of the future generation. In this
paper, we consider energy management for wireless
mesh networks from a point of view that started rec
ently to attract the attention means the conservati
on of
energy for operational and the environment reasons
which is known as the Green Networking. This paper
discusses different routing protocols to establish
a protocol which considers energy efficiency. The e
xisting
protocols are compared using the basic functions of
routing and the suggest protocol is designed to
overcome some of their shortcomings. We are focusin
g on the conception of the cross-layer routing
protocol that is implemented in TDMA (Time Division
Multiple Access) wireless mesh networks based
MAC protocol.
MULTICASTING BASED ENHANCED PROACTIVE SOURCE ROUTING IN MANETSIJCNCJournal
Mobile Ad-hoc Network (MANET) is an accumulation of movable nodes organizing a irregular topology without centralized administration. In a MANET, multicasting is a significant technique for utilizing data communication system. Multicasting based enhanced proactive source routing is proposed in this paper for Mobile Ad hoc Networks. It explains an innovative multicasting algorithm that considers the transmission energy and residual energy while forwarding the data packets. It improves the network throughput and raises the network lifetimes. Simulation analysis is carried in this proposed system and this method shows improved performance over the existing system.
Overview of Improving Robustness of MAODV Protocol by Combining Tree and Mesh...IOSR Journals
This document summarizes research on improving the robustness of the MAODV multicast routing protocol in mobile ad hoc networks. It discusses how MAODV uses a tree structure for routing but lacks redundancy, hurting performance in high load or dynamic networks. The document proposes a new MAODV-BB protocol that combines tree and mesh structures by using group messages to update shorter branches and construct a multicast tree with backup branches. This improves robustness without extra overhead.
The document proposes a full-duplex cognitive MAC (FDC-MAC) protocol for cognitive radio networks. The protocol consists of two stages: (1) a FD sensing stage where secondary users perform concurrent spectrum sensing and transmission at a controlled power level to mitigate self-interference, and (2) a transmission stage where secondary users transmit at maximum power if the sensing stage indicated an available channel. The document develops a mathematical model to analyze the throughput performance of the FDC-MAC protocol and proves that there exists an optimal sensing time and transmit power configuration to maximize throughput. Extensive simulation results demonstrate significant throughput gains of the FDC-MAC protocol over half-duplex and single-stage full-duplex MAC protocols.
Adaptive QoS Multicast Routing with Mobility Prediction in MANETs ijasuc
A Mobile Ad hoc NETwork (MANET) is a collection of wireless mobile hosts that form a temporary network
without a centralized administration or wired infrastructure. Due to the high mobility of nodes, the network
topology of MANETs changes very fast, making it more difficult to find the routes that message packets use.
Network control with Quality of Service (QoS) support is a key issue for multimedia applications in MANET.
Most of the real time applications have stringent requirements on bandwidth, delay, delay-jitter, packet loss
ratio, cost and other QoS metrics. This paper proposes a Multi-constrained QoS routing with mobility
prediction protocol. If the node has enough resources to transmit data packets, it uses the Global
Positioning System (GPS) to get the location information of the mobile nodes and selects the routing path
with the maximum Route Expiration Time (RET). A set of static and mobile agents are used to find the
multicast routes and transmit the packets. Extensive simulations have been conducted to evaluate the
performance of MC_MAODV using Network Simulator (NS-2). The simulation results show that the
proposed protocol achieves good performance in terms of improving packet delivery ratio and minimizing
end-to-end delay.
Recently proposed wireless mesh routing metrics
based on awareness of congestion, load or interference typically
employ queue occupancy of a node's wireless interface to
estimate traffic load. Queue occupancy, however, does not
directly reflect the impact of channel contention from neighbor
nodes. We propose an alternative called the channel load-aware
(CLAW) routing metric that takes into consideration not only
the traffic load within the node itself, but also the degree of
interference and contention within the channel. CLAW uses
local information from a node's MAC layer to estimate channel
busyness and contention levels. It does not require complex
computations, nor the exchange of link-level statistics with
neighbors. Our preliminary results show that CLAW can
identify congested regions within the network and thus enable
the determination of routes around these congested areas. We
present the results of simulations we conducted to evaluate the
use of CLAW in mesh-wide routing.
INVESTIGATING MULTILAYER OMEGA-TYPE NETWORKS OPERATING WITH THE CUT-THROUGH T...IJCNCJournal
The continuous increase in the complexity of data networks has motivated the development of more effective Multistage Interconnection Networks (MINs) as important factors in providing higher data transfer rates in various switching divisions. In this paper, semi-layer omega-class networks operating with a cut-through forwarding technique are chosen as test-bed subjects for detailed evaluation, and this network architecture is modelled, inspected, and simulated. The results are examined for relevant singlelayer omega networks operating with cut-through or ‘store and forward’ forwarding techniques. Two series of experiments are carried out: one concerns the case of uniform traffic, while the other is related to hotspot traffic. The results quantify the way in which this network outperforms the corresponding singlelayer network architectures for the same network size and buffer size. Furthermore, the effects of the dimensions of the switch elements and their corresponding reliability on the overall interconnection system are investigated, and the complexity and the relevant cost are examined. The data yielded by this investigation can be valuable to MIN engineers and can allow them to achieve more productive networks with lower overall implementation costs.
Load aware and load balancing using aomdv routing in manetijctet
This document discusses load aware and load balancing techniques using multipath routing in mobile ad hoc networks (MANETs). It proposes using a location aided routing (LAR) protocol with the Ad-hoc On-demand Multipath Distance Vector (AOMDV) routing protocol to identify multiple routing backbones from the source to destination nodes based on the intermediate nodes' communication and processing capabilities. This helps distribute traffic loads evenly across multiple paths to improve load balancing, reduce congestion, and enhance quality of service in the MANET.
ENERGY LOCATION AWARE ROUTING PROTOCOL (ELARP) FOR WIRELESS MULTIMEDIA SENSOR...ijcsit
Wireless Sensor Networks (WSNs)have sensor nodes that sense and extract information from surrounding
environment, processing information locally then transmit it to sink wirelessly. Multimedia data is larger in
volume than scalar data, thus transmitting multimedia data via Wireless Multimedia Sensor Networks
(WMSNs) requires stick constraints on quality of services in terms of energy, throughput and end to end
delay.Multipath routing is to discover multipath during route discovery from source to sink. Discover
multipath and sending data via these different paths improve the bandwidth and decrease the end to end
delay. This paper introduces an Energy Location Aware Routing Protocol (ELARP) which is reactive
multipath routing protocol establishing three paths with awareness of node’s residual energy and distance.
ELARP has experimented with NS2 simulator. The simulation results show that ELARP enhances QoS for
multimedia data in terms of end to end delay and packet delivery ratio.
MMINIMUM RESOURCE CONSUMPTIONS ROUTING FOR OPTICAL NETWORKSprj_publication
The problem of determining primary and backup paths for survivable optical WDM
networks is considered. Results of various available routing techniques that try to minimize
the combined cost of primary and the backup path are analyzed for the effects on network
parameters such as mean load, variance of the load on route, number of converters required
by the route and the length of the route. The route cost is modelled such a way that it is
extensible to include any new parameter and vary their relative importance. The efficiency of
such wavelength routed networks has been proved to improve for certain parameters, such as
reduction in blocking probability and number of converters required for desired performance.
The routing is enhanced to analyse effect on network parameters for all node full range
converters, limited number full converters, reserved primary and back up wavelengths and
with no such reservation.
Performance analysis of multilayer multicast MANET CRN based on steiner minim...TELKOMNIKA JOURNAL
In this study, the multicast mobile ad hoc (MANET) CRN has been developed, which involves multi-hop and multilayer consideration and Steiner minimal tree (SMT) algorithm is employed as the router protocol. To enhance the network performance with regards to throughput and packet delivery rate (PDR), as channel assignment scheme, the probability of success (POS) is employed that accounts for the channel availability and the time needed for transmission when selecting the best channel from the numerous available channels for data transmission from the source to all destinations nodes effectively. Within Rayleigh fading channels under various network parameters, a comparison is done for the performance of SMT multicast (MANET) CRN with POS scheme versus maximum data rate (MDR), maximum average spectrum availability (MASA) and random channel assignment schemes. Based on the simulation results, the SMT multicast (MANET) CRN with POS scheme was seen to demonstrate the best performance versus other schemes. Also, the results proved that the throughput and PDR performance are improved as the number the primary channels and the channel’s bandwidth increased while dropped as the value of packet size D increased. The network’s performance grew with rise in the value of idle probability (푃퐼) since the primary user’s (PU) traffic load is low when the value of 푃퐼 is high.
Load aware self organising user-centric dynamic co mp clustering for 5g networksredpel dot com
This document summarizes a research paper that proposes a two-stage, load-aware clustering algorithm for coordinated multi-point (CoMP) transmission in 5G networks. In the first stage, the algorithm allows cluster sizes to increase for highly loaded cells to introduce more capacity. The second stage introduces a novel re-clustering method to distribute load from overloaded cells to neighboring cells with lower loads, improving user satisfaction while minimally impacting spectral efficiency. The goal is to enhance an existing user-centric CoMP clustering approach with load awareness to better balance traffic loads across cells in the network.
This document discusses routing metrics in wireless mesh networks. It begins by outlining four key requirements for routing metrics: route stability, finding minimum weight paths, efficient path calculation algorithms, and loop-free routing. It then evaluates several existing routing metrics based on these requirements. These include hop count, RTT, PktPair, ETX, ETT, WCETT, and others. Each metric is described and its advantages and disadvantages are discussed in relation to wireless mesh network characteristics like interference, mobility, and multi-channel usage. The document aims to analyze existing routing metrics to help identify appropriate metrics for wireless mesh networks that conform to their characteristics.
Performance Analysis of Energy Optimized LTE-V2X Networks for Delay Sensitive...IJCNCJournal
This document analyzes the performance of three uplink transmission modes - single-hop direct, multi-hop cellular V2X, and store-carry-forward (SCF) - for delay sensitive real-time services in LTE-V2X networks. It presents a highway system model and compares the total energy consumption and transmission delay of the three modes using numerical simulations validated with ns-3. The results show that SCF mode consumes the least energy due to its carry phase, but incurs high delays unacceptable for real-time applications. Single-hop direct has the reverse performance. Multi-hop cellular V2X outperforms in terms of balancing low latency and moderate energy consumption beyond a cell radius of 600
This document provides information about the Key Activity 2 (KA2) funding program for language projects under the Lifelong Learning Program. It outlines the 6 priorities for KA2 multilateral projects in 2012, which include cooperation between education/training/work, promoting less widely used languages, key competencies in education systems, social inclusion and gender equality, learning neighboring countries' languages, and early language learning. It also describes the 4 priorities for KA2 networks and eligibility criteria. Application quality tips are given, emphasizing coherence, clarity, evidence-based planning, and defining specific issues to address.
Read how the elements of the Educator Effectiveness System--PD 360, Common Core 360, and Observation 360--helped this small-town school district improve teacher effectiveness by focusing on three areas: Common Core State Standards, teacher compliance training, and classroom technology.
Learn more about the Educator Effectiveness System here: http://www.schoolimprovement.com/educator-effectiveness-system/
Musa a las 9 es una editorial digital que busca fusionar todos los aspectos de la industria del libro electrónico, incluida la edición, distribución, derechos de autor y participación de lectores. Ofrece una selección cuidadosa de obras en formato ebook y PDF para lectura en línea a precios accesibles de forma permanente. Además de publicar colecciones en varios géneros literarios, la editorial mantiene un sitio web y presencia en redes sociales para promover la literatura y el diálogo entre lectores.
El documento describe un proyecto presentado al Stockolm Junior Water Prize 2010 titulado "Diseño de un sistema de climatización mediante ventanas con cámara de agua" realizado por Ana Esteban Baloira y Uxía Fernández Bustillo.
The document discusses "pattern interrupts", which are techniques one can use when a conversation starts deteriorating or someone becomes upset. Some examples of pattern interrupts include saying "hey!", "whoa!", or asking a clarifying question. The goal is to interrupt the pattern, check for understanding of perspectives, and confirm understanding to de-escalate tensions. Mastering good communication techniques like pattern interrupts can help reduce stress during difficult conversations.
Este documento habla sobre la importancia del marketing móvil para las marcas en la era digital. Recomienda que las empresas desarrollen sitios web adaptados a dispositivos móviles, usen códigos QR, realidad aumentada y aplicaciones para estar donde están los consumidores. También discute el potencial de la realidad aumentada y las aplicaciones móviles para ofrecer publicidad no invasiva y contenidos de marca memorables.
Energy efficiency cross layer protocol for wireless mesh networkIJCNCJournal
Wireless mesh network (WMN) is a novel emerging tec
hnology that will change the world more effectively
and efficiently. It is regarded as a highly promisi
ng technology being increasingly important in mobil
e
wireless networks of the future generation. In this
paper, we consider energy management for wireless
mesh networks from a point of view that started rec
ently to attract the attention means the conservati
on of
energy for operational and the environment reasons
which is known as the Green Networking. This paper
discusses different routing protocols to establish
a protocol which considers energy efficiency. The e
xisting
protocols are compared using the basic functions of
routing and the suggest protocol is designed to
overcome some of their shortcomings. We are focusin
g on the conception of the cross-layer routing
protocol that is implemented in TDMA (Time Division
Multiple Access) wireless mesh networks based
MAC protocol.
MULTICASTING BASED ENHANCED PROACTIVE SOURCE ROUTING IN MANETSIJCNCJournal
Mobile Ad-hoc Network (MANET) is an accumulation of movable nodes organizing a irregular topology without centralized administration. In a MANET, multicasting is a significant technique for utilizing data communication system. Multicasting based enhanced proactive source routing is proposed in this paper for Mobile Ad hoc Networks. It explains an innovative multicasting algorithm that considers the transmission energy and residual energy while forwarding the data packets. It improves the network throughput and raises the network lifetimes. Simulation analysis is carried in this proposed system and this method shows improved performance over the existing system.
Overview of Improving Robustness of MAODV Protocol by Combining Tree and Mesh...IOSR Journals
This document summarizes research on improving the robustness of the MAODV multicast routing protocol in mobile ad hoc networks. It discusses how MAODV uses a tree structure for routing but lacks redundancy, hurting performance in high load or dynamic networks. The document proposes a new MAODV-BB protocol that combines tree and mesh structures by using group messages to update shorter branches and construct a multicast tree with backup branches. This improves robustness without extra overhead.
The document proposes a full-duplex cognitive MAC (FDC-MAC) protocol for cognitive radio networks. The protocol consists of two stages: (1) a FD sensing stage where secondary users perform concurrent spectrum sensing and transmission at a controlled power level to mitigate self-interference, and (2) a transmission stage where secondary users transmit at maximum power if the sensing stage indicated an available channel. The document develops a mathematical model to analyze the throughput performance of the FDC-MAC protocol and proves that there exists an optimal sensing time and transmit power configuration to maximize throughput. Extensive simulation results demonstrate significant throughput gains of the FDC-MAC protocol over half-duplex and single-stage full-duplex MAC protocols.
Adaptive QoS Multicast Routing with Mobility Prediction in MANETs ijasuc
A Mobile Ad hoc NETwork (MANET) is a collection of wireless mobile hosts that form a temporary network
without a centralized administration or wired infrastructure. Due to the high mobility of nodes, the network
topology of MANETs changes very fast, making it more difficult to find the routes that message packets use.
Network control with Quality of Service (QoS) support is a key issue for multimedia applications in MANET.
Most of the real time applications have stringent requirements on bandwidth, delay, delay-jitter, packet loss
ratio, cost and other QoS metrics. This paper proposes a Multi-constrained QoS routing with mobility
prediction protocol. If the node has enough resources to transmit data packets, it uses the Global
Positioning System (GPS) to get the location information of the mobile nodes and selects the routing path
with the maximum Route Expiration Time (RET). A set of static and mobile agents are used to find the
multicast routes and transmit the packets. Extensive simulations have been conducted to evaluate the
performance of MC_MAODV using Network Simulator (NS-2). The simulation results show that the
proposed protocol achieves good performance in terms of improving packet delivery ratio and minimizing
end-to-end delay.
Recently proposed wireless mesh routing metrics
based on awareness of congestion, load or interference typically
employ queue occupancy of a node's wireless interface to
estimate traffic load. Queue occupancy, however, does not
directly reflect the impact of channel contention from neighbor
nodes. We propose an alternative called the channel load-aware
(CLAW) routing metric that takes into consideration not only
the traffic load within the node itself, but also the degree of
interference and contention within the channel. CLAW uses
local information from a node's MAC layer to estimate channel
busyness and contention levels. It does not require complex
computations, nor the exchange of link-level statistics with
neighbors. Our preliminary results show that CLAW can
identify congested regions within the network and thus enable
the determination of routes around these congested areas. We
present the results of simulations we conducted to evaluate the
use of CLAW in mesh-wide routing.
INVESTIGATING MULTILAYER OMEGA-TYPE NETWORKS OPERATING WITH THE CUT-THROUGH T...IJCNCJournal
The continuous increase in the complexity of data networks has motivated the development of more effective Multistage Interconnection Networks (MINs) as important factors in providing higher data transfer rates in various switching divisions. In this paper, semi-layer omega-class networks operating with a cut-through forwarding technique are chosen as test-bed subjects for detailed evaluation, and this network architecture is modelled, inspected, and simulated. The results are examined for relevant singlelayer omega networks operating with cut-through or ‘store and forward’ forwarding techniques. Two series of experiments are carried out: one concerns the case of uniform traffic, while the other is related to hotspot traffic. The results quantify the way in which this network outperforms the corresponding singlelayer network architectures for the same network size and buffer size. Furthermore, the effects of the dimensions of the switch elements and their corresponding reliability on the overall interconnection system are investigated, and the complexity and the relevant cost are examined. The data yielded by this investigation can be valuable to MIN engineers and can allow them to achieve more productive networks with lower overall implementation costs.
Load aware and load balancing using aomdv routing in manetijctet
This document discusses load aware and load balancing techniques using multipath routing in mobile ad hoc networks (MANETs). It proposes using a location aided routing (LAR) protocol with the Ad-hoc On-demand Multipath Distance Vector (AOMDV) routing protocol to identify multiple routing backbones from the source to destination nodes based on the intermediate nodes' communication and processing capabilities. This helps distribute traffic loads evenly across multiple paths to improve load balancing, reduce congestion, and enhance quality of service in the MANET.
ENERGY LOCATION AWARE ROUTING PROTOCOL (ELARP) FOR WIRELESS MULTIMEDIA SENSOR...ijcsit
Wireless Sensor Networks (WSNs)have sensor nodes that sense and extract information from surrounding
environment, processing information locally then transmit it to sink wirelessly. Multimedia data is larger in
volume than scalar data, thus transmitting multimedia data via Wireless Multimedia Sensor Networks
(WMSNs) requires stick constraints on quality of services in terms of energy, throughput and end to end
delay.Multipath routing is to discover multipath during route discovery from source to sink. Discover
multipath and sending data via these different paths improve the bandwidth and decrease the end to end
delay. This paper introduces an Energy Location Aware Routing Protocol (ELARP) which is reactive
multipath routing protocol establishing three paths with awareness of node’s residual energy and distance.
ELARP has experimented with NS2 simulator. The simulation results show that ELARP enhances QoS for
multimedia data in terms of end to end delay and packet delivery ratio.
MMINIMUM RESOURCE CONSUMPTIONS ROUTING FOR OPTICAL NETWORKSprj_publication
The problem of determining primary and backup paths for survivable optical WDM
networks is considered. Results of various available routing techniques that try to minimize
the combined cost of primary and the backup path are analyzed for the effects on network
parameters such as mean load, variance of the load on route, number of converters required
by the route and the length of the route. The route cost is modelled such a way that it is
extensible to include any new parameter and vary their relative importance. The efficiency of
such wavelength routed networks has been proved to improve for certain parameters, such as
reduction in blocking probability and number of converters required for desired performance.
The routing is enhanced to analyse effect on network parameters for all node full range
converters, limited number full converters, reserved primary and back up wavelengths and
with no such reservation.
Performance analysis of multilayer multicast MANET CRN based on steiner minim...TELKOMNIKA JOURNAL
In this study, the multicast mobile ad hoc (MANET) CRN has been developed, which involves multi-hop and multilayer consideration and Steiner minimal tree (SMT) algorithm is employed as the router protocol. To enhance the network performance with regards to throughput and packet delivery rate (PDR), as channel assignment scheme, the probability of success (POS) is employed that accounts for the channel availability and the time needed for transmission when selecting the best channel from the numerous available channels for data transmission from the source to all destinations nodes effectively. Within Rayleigh fading channels under various network parameters, a comparison is done for the performance of SMT multicast (MANET) CRN with POS scheme versus maximum data rate (MDR), maximum average spectrum availability (MASA) and random channel assignment schemes. Based on the simulation results, the SMT multicast (MANET) CRN with POS scheme was seen to demonstrate the best performance versus other schemes. Also, the results proved that the throughput and PDR performance are improved as the number the primary channels and the channel’s bandwidth increased while dropped as the value of packet size D increased. The network’s performance grew with rise in the value of idle probability (푃퐼) since the primary user’s (PU) traffic load is low when the value of 푃퐼 is high.
Load aware self organising user-centric dynamic co mp clustering for 5g networksredpel dot com
This document summarizes a research paper that proposes a two-stage, load-aware clustering algorithm for coordinated multi-point (CoMP) transmission in 5G networks. In the first stage, the algorithm allows cluster sizes to increase for highly loaded cells to introduce more capacity. The second stage introduces a novel re-clustering method to distribute load from overloaded cells to neighboring cells with lower loads, improving user satisfaction while minimally impacting spectral efficiency. The goal is to enhance an existing user-centric CoMP clustering approach with load awareness to better balance traffic loads across cells in the network.
This document discusses routing metrics in wireless mesh networks. It begins by outlining four key requirements for routing metrics: route stability, finding minimum weight paths, efficient path calculation algorithms, and loop-free routing. It then evaluates several existing routing metrics based on these requirements. These include hop count, RTT, PktPair, ETX, ETT, WCETT, and others. Each metric is described and its advantages and disadvantages are discussed in relation to wireless mesh network characteristics like interference, mobility, and multi-channel usage. The document aims to analyze existing routing metrics to help identify appropriate metrics for wireless mesh networks that conform to their characteristics.
Performance Analysis of Energy Optimized LTE-V2X Networks for Delay Sensitive...IJCNCJournal
This document analyzes the performance of three uplink transmission modes - single-hop direct, multi-hop cellular V2X, and store-carry-forward (SCF) - for delay sensitive real-time services in LTE-V2X networks. It presents a highway system model and compares the total energy consumption and transmission delay of the three modes using numerical simulations validated with ns-3. The results show that SCF mode consumes the least energy due to its carry phase, but incurs high delays unacceptable for real-time applications. Single-hop direct has the reverse performance. Multi-hop cellular V2X outperforms in terms of balancing low latency and moderate energy consumption beyond a cell radius of 600
This document provides information about the Key Activity 2 (KA2) funding program for language projects under the Lifelong Learning Program. It outlines the 6 priorities for KA2 multilateral projects in 2012, which include cooperation between education/training/work, promoting less widely used languages, key competencies in education systems, social inclusion and gender equality, learning neighboring countries' languages, and early language learning. It also describes the 4 priorities for KA2 networks and eligibility criteria. Application quality tips are given, emphasizing coherence, clarity, evidence-based planning, and defining specific issues to address.
Read how the elements of the Educator Effectiveness System--PD 360, Common Core 360, and Observation 360--helped this small-town school district improve teacher effectiveness by focusing on three areas: Common Core State Standards, teacher compliance training, and classroom technology.
Learn more about the Educator Effectiveness System here: http://www.schoolimprovement.com/educator-effectiveness-system/
Musa a las 9 es una editorial digital que busca fusionar todos los aspectos de la industria del libro electrónico, incluida la edición, distribución, derechos de autor y participación de lectores. Ofrece una selección cuidadosa de obras en formato ebook y PDF para lectura en línea a precios accesibles de forma permanente. Además de publicar colecciones en varios géneros literarios, la editorial mantiene un sitio web y presencia en redes sociales para promover la literatura y el diálogo entre lectores.
El documento describe un proyecto presentado al Stockolm Junior Water Prize 2010 titulado "Diseño de un sistema de climatización mediante ventanas con cámara de agua" realizado por Ana Esteban Baloira y Uxía Fernández Bustillo.
The document discusses "pattern interrupts", which are techniques one can use when a conversation starts deteriorating or someone becomes upset. Some examples of pattern interrupts include saying "hey!", "whoa!", or asking a clarifying question. The goal is to interrupt the pattern, check for understanding of perspectives, and confirm understanding to de-escalate tensions. Mastering good communication techniques like pattern interrupts can help reduce stress during difficult conversations.
Este documento habla sobre la importancia del marketing móvil para las marcas en la era digital. Recomienda que las empresas desarrollen sitios web adaptados a dispositivos móviles, usen códigos QR, realidad aumentada y aplicaciones para estar donde están los consumidores. También discute el potencial de la realidad aumentada y las aplicaciones móviles para ofrecer publicidad no invasiva y contenidos de marca memorables.
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Improvement at Network Planning using Heuristic Algorithm to Minimize Cost of...Yayah Zakaria
Wireless Mesh Networks (WMN) consists of wireless stations that are connected with each other in a semi-static configuration. Depending on the configuration of a WMN, different paths between nodes offer different levels of efficiency. One areas of research with regard to WMN is cost minimization. A Modified Binary Particle Swarm Optimization (MBPSO) approach was used to optimize cost. However, minimized cost does not
guarantee network performance. This paper thus, modified the minimization function to take into consideration the distance between the different nodes so as to enable better performance while maintaining cost balance. The results were positive with the PDR showing an approximate increase of 17.83% whereas the E2E delay saw an approximate decrease of 8.33%.
Improvement at Network Planning using Heuristic Algorithm to Minimize Cost of...IJECEIAES
Wireless Mesh Networks (WMN) consists of wireless stations that are connected with each other in a semi-static configuration. Depending on the configuration of a WMN, different paths between nodes offer different levels of efficiency. One areas of research with regard to WMN is cost minimization. A Modified Binary Particle Swarm Optimization (MBPSO) approach was used to optimize cost. However, minimized cost does not guarantee network performance. This paper thus, modified the minimization function to take into consideration the distance between the different nodes so as to enable better performance while maintaining cost balance. The results were positive with the PDR showing an approximate increase of 17.83% whereas the E2E delay saw an approximate decrease of 8.33%.
Traffic-aware adaptive server load balancing for softwaredefined networks IJECEIAES
Servers in data center networks handle heterogeneous bulk loads. Load balancing, therefore, plays an important role in optimizing network bandwidth and minimizing response time. A complete knowledge of the current network status is needed to provide a stable load in the network. The process of network status catalog in a traditional network needs additional processing which increases complexity, whereas, in software defined networking, the control plane monitors the overall working of the network continuously. Hence it is decided to propose an efficient load balancing algorithm that adapts SDN. This paper proposes an efficient algorithm TAASLB-traffic-aware adaptive server load balancing to balance the flows to the servers in a data center network. It works based on two parameters, residual bandwidth, and server capacity. It detects the elephant flows and forwards them towards the optimal server where it can be processed quickly. It has been tested with the Mininet simulator and gave considerably better results compared to the existing server load balancing algorithms in the floodlight controller. After experimentation and analysis, it is understood that the method provides comparatively better results than the existing load balancing algorithms.
Active Path Updation For Layered Routing (Apular) In Wireless Mesh Networkschetan1nonly
1) The document proposes an Active Path Updation procedure (APULAR) for layered routing in wireless mesh networks to quickly update broken paths and reduce packet loss.
2) In APULAR, the destination node takes responsibility for local repair restoration instead of the source node initiating a new path discovery when a link breaks, as is typically done.
3) The procedure is simulated and shown to outperform AODV and IWMRA routing protocols, achieving better packet delivery ratio, lower control overhead, higher throughput, and lower end-to-end delay.
Active path updation for layered routing (apular) in wirelessAlexander Decker
1) The document proposes an Active Path Updation procedure (APULAR) for layered routing in wireless mesh networks to quickly update broken paths and reduce packet loss.
2) In APULAR, the destination node takes responsibility for local repair restoration instead of the source node initiating a new path discovery when a link breaks, as is typically done.
3) The procedure is simulated and shown to outperform AODV and IWMRA routing protocols, achieving better packet delivery ratio, lower control overhead, higher throughput, and lower end-to-end delay.
Efficient energy, cost reduction, and QoS based routing protocol for wireless...IJECEIAES
Recent developments and widespread in wireless sensor network have led to many routing protocols, many of these protocols consider the efficiency of energy as the ultimate factor to maximize the WSN lifetime. The quality of Service (QoS) requirements for different applications of wireless sensor networks has posed additional challenges. Imaging and data transmission needs both QoS aware routing and energy to ensure the efficient use of sensors. In this paper, we propose an Efficient, Energy-Aware, Least Cost, (ECQSR) quality of service routing protocol for sensor networks which can run efficiently with best-effort traffic processing. The protocol aims to maximize the lifetime of the network out of balancing energy consumption across multiple nodes, by using the concept of service differentiation, finding lower cost by finding the shortest path using nearest neighbor algorithm (NN), also put certain constraints on the delay of the path for real-time data from where link cost that captures energy nodes reserve, energy of the transmission, error rate and other parameters. The results show that the proposed protocol improves the network lifetime and low power consumption.
Adaptive Routing in Wireless Sensor Networks: QoS Optimisation for Enhanced A...M H
The document describes a new routing protocol called Route Optimization and Load-balancing (ROL) for wireless sensor networks. ROL aims to balance several objectives like prolonging network lifetime, providing timely message delivery, and improving network robustness. It uses a combination of routing metrics that can be configured according to application priorities to optimize overall network performance. Simulation results show that ROL maintains balanced cluster sizes and populations, reduces overhead, end-to-end delays, and improves data delivery ratios compared to other protocols like Mires++.
Wireless mesh networks offer high bandwidth Internet access for mobile users anywhere and at any time.
It is an emerging technology that uses wireless multi-hop networking to provide a cost-efficient way for
community or enterprise users to have broadband Internet access and share network resource. In this paper,
we have tried to give a comparative analysis of various Gateway Placement approaches which can be
helpful in understanding which approach will be useful in which situation.
Load balancing In Wireless Mesh Networks Using liquid–Simulated AlgorithmIJSRED
The document proposes a hierarchical routing framework and liquid-simulated algorithm for load balancing in wireless mesh networks. Key points:
- The framework forms clusters with wireless mesh routers (WMRs) as cluster heads and simplifies clustering procedures. It uses limited topology broadcasting to allow WMRs to choose best paths between adjacent clusters.
- The liquid-simulated algorithm aims to keep load balanced between WMRs by treating load as a liquid level and allowing flows between nodes to equalize levels across the network.
- The framework uses a proactive routing approach within this load balancing algorithm, with topology broadcasting constrained within clusters and adjacent clusters to reduce overhead.
Multipath Routing Protocol by Breadth First Search Algorithm in Wireless Mesh...IOSR Journals
This document proposes a multipath routing protocol for wireless mesh networks that uses a parallel layer-based approach and breadth-first search algorithm to discover multiple paths between a source and destination. It organizes nodes into layers based on distance from the destination and performs iterative breadth-first searches to find partial paths connecting nodes in lower layers, storing the partial paths. This process repeats until reaching the destination to find all possible paths. The primary path is then elected using an Expected Forwarding Counter metric to select the most reliable path. The protocol was evaluated in NS-2 and showed improved throughput, delivery ratio, and reduced delay compared to other protocols.
An optimized link state routing protocol based on a cross layer design for wi...IOSR Journals
This document discusses an optimized link state routing protocol based on a cross-layer design for wireless mesh networks. It proposes monitoring link quality at the MAC layer and notifying the network layer of changes, allowing routes to be automatically updated without a refresh phase. This provides seamless connectivity under varying load and mobility. Traditional routing protocols either have fast but vulnerable proactive routes or add overhead with reactive routes. The proposed cross-layer design monitors links continuously and performs vertical handovers to better links to avoid these issues.
Design and implementation of new routingIJCNCJournal
Energy consumption is a key element in the Wireless Sensor Networks (WSNs) design. Indeed, sensor nodes are really constrained by energy supply. Hence, how to improve the network lifetime is a crucial and challenging task. Several techniques are available at different levels of the OSI model to maximize the WSN lifetime and especially at the network layer which uses routing strategies to maintain the routes in the network and guarantee reliable communication. In this paper we intend to propose a new protocol called
Combined Energy and Distance Metrics Dynamic Routing Protocol (CEDM-DR). Our new approach considers not only the distance between wireless sensors but also the energy of node acting as a router in order to find the optimal path and achieve a dynamic and adaptive routing.
The performance metrics exploited for the evaluation of our protocol are average energy consumed, network lifetime and packets lost. By comparing our proposed routing strategy to protocol widely used in WSN namely Ad hoc On demand Distance Vector(AODV), simulation results show that CEDM-DR strategy might effectively balance the sensor power consumption and permits accordingly to enhance the network
lifetime. As well, this new protocol yields a noticeable energy saving compared to its counterpart.
This document summarizes a research paper that proposes an energy and bandwidth constrained routing technique for mobile ad hoc networks (MANETs). It presents an available bandwidth measurement algorithm that estimates available bandwidth more accurately by considering node capacity, link utilization, idle time synchronization, collision probability, and overhead from backoff mechanisms. It also proposes a probability-based overhearing method to reduce energy consumption from overhearing without affecting route quality. The techniques are evaluated using NS2 simulations to analyze network performance in terms of quality of service parameters.
DETERMINING THE NETWORK THROUGHPUT AND FLOW RATE USING GSR AND AAL2Rijujournal
In multi-radio wireless mesh networks, one node is eligible to transmit packets over multiple channels to
different destination nodes simultaneously. This feature of multi-radio wireless mesh network makes high
throughput for the network and increase the chance for multi path routing. This is because the multiple
channel availability for transmission decreases the probability of the most elegant problem called as
interference problem which is either of interflow and intraflow type. For avoiding the problem like
interference and maintaining the constant network performance or increasing the performance the WMN
need to consider the packet aggregation and packet forwarding. Packet aggregation is process of collecting
several packets ready for transmission and sending them to the intended recipient through the channel,
while the packet forwarding holds the hop-by-hop routing. But choosing the correct path among different
available multiple paths is most the important factor in the both case for a routing algorithm. Hence the
most challenging factor is to determine a forwarding strategy which will provide the schedule for each
node for transmission within the channel. In this research work we have tried to implement two forwarding
strategies for the multi path multi radio WMN as the approximate solution for the above said problem. We
have implemented Global State Routing (GSR) which will consider the packet forwarding concept and
Aggregation Aware Layer 2 Routing (AAL2R) which considers the both concept i.e. both packet forwarding
and packet aggregation. After the successful implementation the network performance has been measured
by means of simulation study.
DETERMINING THE NETWORK THROUGHPUT AND FLOW RATE USING GSR AND AAL2Rijujournal
In multi-radio wireless mesh networks, one node is eligible to transmit packets over multiple channels to
different destination nodes simultaneously. This feature of multi-radio wireless mesh network makes high
throughput for the network and increase the chance for multi path routing. This is because the multiple
channel availability for transmission decreases the probability of the most elegant problem called as
interference problem which is either of interflow and intraflow type. For avoiding the problem like
interference and maintaining the constant network performance or increasing the performance the WMN
need to consider the packet aggregation and packet forwarding. Packet aggregation is process of collecting
several packets ready for transmission and sending them to the intended recipient through the channel,
while the packet forwarding holds the hop-by-hop routing. But choosing the correct path among different
available multiple paths is most the important factor in the both case for a routing algorithm. Hence the
most challenging factor is to determine a forwarding strategy which will provide the schedule for each
node for transmission within the channel. In this research work we have tried to implement two forwarding
strategies for the multi path multi radio WMN as the approximate solution for the above said problem. We
have implemented Global State Routing (GSR) which will consider the packet forwarding concept and
Aggregation Aware Layer 2 Routing (AAL2R) which considers the both concept i.e. both packet forwarding
and packet aggregation. After the successful implementation the network performance has been measured
by means of simulation study.
DETERMINING THE NETWORK THROUGHPUT AND FLOW RATE USING GSR AND AAL2Rijujournal
In multi-radio wireless mesh networks, one node is eligible to transmit packets over multiple channels to different destination nodes simultaneously. This feature of multi-radio wireless mesh network makes high throughput for the network and increase the chance for multi path routing. This is because the multiple channel availability for transmission decreases the probability of the most elegant problem called as interference problem which is either of interflow and intraflow type. For avoiding the problem like interference and maintaining the constant network performance or increasing the performance the WMN need to consider the packet aggregation and packet forwarding. Packet aggregation is process of collecting several packets ready for transmission and sending them to the intended recipient through the channel, while the packet forwarding holds the hop-by-hop routing. But choosing the correct path among different available multiple paths is most the important factor in the both case for a routing algorithm. Hence the most challenging factor is to determine a forwarding strategy which will provide the schedule for each node for transmission within the channel. In this research work we have tried to implement two forwarding strategies for the multi path multi radio WMN as the approximate solution for the above said problem. We have implemented Global State Routing (GSR) which will consider the packet forwarding concept and Aggregation Aware Layer 2 Routing (AAL2R) which considers the both concept i.e. both packet forwarding and packet aggregation. After the successful implementation the network performance has been measured by means of simulation study.
This document provides an overview of wireless mesh networks (WMNs). It discusses the types of nodes in WMNs including wireless mesh routers and mesh clients. It describes the different architectures of WMNs and characteristics such as low cost, integration capabilities, and applications like broadband networking. Key challenges are also addressed around developing high-capacity radio interfaces and resource management. The document serves as an introduction to WMNs covering topics from architecture and standards to research opportunities.
A survey on routing algorithms and routing metrics for wireless mesh networksMohammad Siraj
This document summarizes a survey on routing algorithms and metrics for wireless mesh networks. It discusses the requirements of efficient mesh routing protocols including being distributed, adaptable to topology changes, loop-free, secure, scalable, and supporting quality of service. It reviews several important proactive routing protocols including destination-sequenced distance-vector routing, optimized link state routing, and mesh networking routing protocol. It also discusses reactive routing protocols and examples like dynamic source routing and ad hoc on-demand distance vector routing. Finally, it examines routing metrics and their impact on the performance of wireless mesh networks.
A New Paradigm for Load Balancing in WMNsCSCJournals
In this paper, we address the problem of load balancing in Wireless Mesh Networks. We consider a Cluster Based Wireless Mesh Architecture in which the WMN is divided into clusters that could minimize the updating overhead during topology change due to mobility of mesh nodes or congestion of load on a cluster. Each cluster contains a gateway that has complete knowledge about group memberships and link state information in the cluster. The gateway is often elected in the cluster formation process. We consider load of gateways and try to reduce it. As a matter of fact when a gateway undertakes to be an interface for connecting nodes of a wireless mesh network to other networks or internet, there would be some problems such as congestion and bottleneck, so we introduce a new paradigm for these problems. For solving bottleneck we use clustering to reduce load of gateways and after that by use of dividing cluster we prevent from bottleneck on gateways. We study how to detect congestion on a gateway and how can reduce loads of it that preventing from bottleneck on gateway and therefore increasing throughput of network to encountering many loads. So we propose an algorithm to detect bottleneck and remedies for load balancing in Wireless Mesh Networks. We also use Ns2-Emultion for implementing and testing the framework. Some qualitative results are provided to prove the correctness and the advantages of our framework.
Similar to Efficient load aware routing scheme (20)
Bulk Projects For sale
IEEE 2009-10-11-12-13 PAPERS AVILABLE.
We are providing low cost project for final year student projects.
Solved 2010 -2011 -2012 - 2013 IEEE in all the domain
Mobile : 8940956123
E-Mail : ambitlick@gmail.com,
INNOVATIVE TITLES ARE ALSO WELLCOME TO DO WITH US
For All BE/BTech, ME/MTech, MSC/MCA/MS , and diplamo graduates
PROJECT SUPPORTS & DELIVERABLES
•Project Abstract
•IEEE Paper
•PPT / Review Details
•Project Report
•Working Procedure in Video
•Screen Shots
•Materials & Books in CD
•Project Certification
This document lists 15 potential 2013 IEEE NS2 project titles related to wireless networks and sensor networks. It includes projects on topics like capacity of hybrid wireless mesh networks, delay-optimal broadcast in multihop wireless networks, detection of spoofing attackers, and harvesting-aware energy management for wireless sensor networks. The document provides contact information for a company called Ambitlick Solutions that offers support and deliverables for IEEE projects, including project abstracts, papers, presentations, reports, and certification.
This document lists over 40 potential 2013 IEEE Java Dotnet project titles across various domains including wireless networks, mobile computing, network security, data mining, cloud computing, parallel and distributed computing, and multimedia/image processing. The projects focus on technical topics such as wireless sensor networks, wireless mesh networks, cognitive radio networks, mobile ad hoc networks, network coding, video streaming, machine learning, data warehousing, and more. Project deliverables include an abstract, IEEE paper, presentation, report, working prototype or proof of concept, and certification. Bulk older and new projects can be provided at a low cost.
Handling selfishness in replica allocationambitlick
The document discusses techniques for handling selfish nodes in replica allocation over mobile ad hoc networks. It aims to reduce traffic overhead while maintaining high data accessibility. The techniques include a selfish node detection algorithm that considers partial selfishness and novel replica allocation methods to address issues caused by selfish nodes hoarding replicas for their own benefit instead of sharing memory space. Simulations are used to evaluate the performance of these techniques in improving data delivery rates.
Mutual Distance Bounding Protocols enable entities to determine an upper bound on their physical distance and authenticate each other. They have been actively researched due to distance-based attacks on wireless systems like RFID. While most protocols provide unilateral authentication of a tag to a reader, one was proposed to provide mutual authentication with a lower false acceptance rate. However, this analysis is shown to overestimate security, as a new attack achieves a higher false acceptance rate. A method is also introduced to modify existing unilateral authentication protocols into mutual authentication protocols.
Moderated group authoring system for campus wide workgroupsambitlick
This paper describes a distributed authoring system for campus workgroups that allows group members to modify any document type using their own devices. Each member maintains an updatable copy of shared content, and read-only copies are distributed asynchronously based on wireless availability. Group members manually reconcile updates through moderation, merging changes from others into their copy. Over time, successive moderation converges all copies into a single version. An evaluation found the asynchronous update model effective and the moderation process intuitive for students.
Efficient spread spectrum communication without pre shared secretsambitlick
This document proposes a new mechanism called Time Reversed Message Extraction and Key Scheduling (TREKS) that allows for efficient spread spectrum communication without pre-shared secrets. TREKS is four orders of magnitude faster than previous solutions to this problem. It enables long-term spread spectrum communication with optimal energy costs, minimal storage overhead, and a computation cost at most twice traditional spread spectrum. The approach was evaluated through simulations and experiments sustaining 1Mbps communication spread over 100 Megachips per second using modest hardware.
The document lists 23 networking and mobile computing projects implemented in NS2. It includes projects on topics like mobility in wireless networks, intrusion detection, neighbor discovery, energy renewal with wireless power transfer, load balancing, and spectrum access control. Contact information is provided for those interested in the project reports, presentations, source code, or implementing new projects.
Adaptive weight factor estimation from user review 1ambitlick
This document proposes a novel technique called Adjacent Pair Priorities (APP) to estimate weight factors for quality of service parameters in vertical handoff decision algorithms. The APP technique allows users to set relative priority levels for adjacent pairs of QoS parameters in descending order using an exponential mapping. This adaptive approach controls the width of the weight distribution to provide flexibility for users. The document outlines the system requirements, block diagram, modules and references several research papers on vertical handoff decision schemes and network selection algorithms.
The document proposes an Integrated Institutional Portal that allows all colleges and institutions within a university or district to share information. [1] The portal would allow students and staff from different colleges to discuss and request information from one another through blogs, forums and by publishing notices. [2] Currently, each college maintains separate portals without a common forum for communication. [3] The proposed centralized portal managed by a super administrator would make all college information like results, events and departments accessible to benefit students and staff across institutions.
This document describes an Embassy Administration portal that aims to centralize and automate manual processes at a college. [1] The portal allows separate login access for staff, parents, students and other members of the college. [2] It displays student results, attendance, and performance for parents to view as well as enables communication between parents and faculty. [3] The system conducts model and unit examinations.
The document proposes a customer relationship management system (CRMS) to help space marketing executives, managers, and management interact and share information online. The existing CRMS is manual and DOS-based, which has disadvantages like a distributed database, obsolete technology, and low efficiency. The proposed system is a web-based online CRMS designed for the space marketing department. It allows monitoring executive calls, tracking performance, and sharing information among departments to improve customer relationships and business operations. The system has modules for corporate administration, regional management, center management, and executives to organize work and monitor progress at different levels.
Mutual Distance Bounding Protocols enable entities to determine an upper bound on their physical distance and authenticate each other. They have been actively researched due to distance-based attacks on wireless systems like RFID. While most protocols provide unilateral authentication of a tag to a reader, one was proposed to provide mutual authentication with a lower false acceptance rate. However, this analysis is shown to overestimate security, as a new attack achieves a higher false acceptance rate. A method is also introduced to modify existing unilateral authentication protocols into mutual authentication protocols.
Moderated group authoring system for campus wide workgroupsambitlick
This paper describes a distributed authoring system for campus workgroups that allows group members to modify any document type using their own devices. Each member maintains an updatable copy of shared content, and read-only copies are distributed based on wireless availability. Group members manually reconcile updates through moderation, merging changes from others into their copy. Over time, successive moderations converge the multiple versions into a single version. An evaluation found the asynchronous update propagation and moderation process intuitive for students.
Efficient spread spectrum communication without pre shared secretsambitlick
This document proposes a new mechanism called Time Reversed Message Extraction and Key Scheduling (TREKS) that allows for efficient spread spectrum communication without pre-shared secrets. TREKS is four orders of magnitude faster than previous solutions to this problem and enables long-term spread spectrum communication without establishing keys. It was evaluated through simulation and on a testbed and can sustain 1Mbps communication spread over a 100 Megachips bandwidth in real-time, with provably optimal energy cost and minimal storage overhead.
Comments on “mabs multicast authentication based on batch signature”ambitlick
This document summarizes and critiques the MABS-DSA protocol proposed by Zhou et al. for multicast authentication using batch verification. While MABS-DSA was intended to increase efficiency and security over other implementations, the author finds through reexamination of the arithmetic that the algorithm is actually incorrect and batch signature verification would fail almost always, even when individual packets were properly signed by an honest sender. The key issue is a flaw in protocol correctness rather than the intended security improvements.
Energy-Efficient Protocol for Deterministic and Probabilistic Coverage In Sen...ambitlick
The document proposes a new probabilistic coverage protocol (PCP) for sensor networks that can employ different sensing models. PCP aims to address the costly task of designing and testing different coverage protocols for each sensing model. It works with common disk sensing models as well as probabilistic sensing models with minimal changes. Simulation results show that PCP outperforms other deterministic and probabilistic protocols in terms of number of activated sensors, total energy consumed, and network lifetime while being robust against failures and inaccuracies.
Energy efficient protocol for deterministicambitlick
The document describes a new probabilistic coverage protocol (PCP) for sensor networks that can employ both deterministic and probabilistic sensing models. PCP works by activating sensors to construct an approximate triangular lattice over the monitored area. It is more energy efficient than previous protocols by reducing the number of activated sensors needed for coverage. Simulation results show PCP outperforms other protocols in terms of energy consumption and network lifetime while maintaining coverage under various conditions.
Estimating Parameters of Multiple Heterogeneous Target Objects Using Composit...ambitlick
This article proposes a method for estimating parameters of multiple heterogeneous target objects (objects with different sizes and shapes) using networked binary sensors. The sensors are simple and only report detections, but no individual sensor location is known. The method introduces "composite sensor nodes" containing multiple sensors in a fixed arrangement. This provides relative location information to help distinguish individual target objects. As an example, the article considers a composite node with two sensors on a line segment. Measures from these nodes can identify target shapes and estimate object parameters like radius and side lengths. Numerical tests demonstrate networked composite sensors can estimate parameters of multiple target objects.
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
-------------------------------------------------------------------------------
Find out more about ISO training and certification services
Training: ISO/IEC 27001 Information Security Management System - EN | PECB
ISO/IEC 42001 Artificial Intelligence Management System - EN | PECB
General Data Protection Regulation (GDPR) - Training Courses - EN | PECB
Webinars: https://pecb.com/webinars
Article: https://pecb.com/article
-------------------------------------------------------------------------------
For more information about PECB:
Website: https://pecb.com/
LinkedIn: https://www.linkedin.com/company/pecb/
Facebook: https://www.facebook.com/PECBInternational/
Slideshare: http://www.slideshare.net/PECBCERTIFICATION
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
1. IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 9, NO. 9, SEPTEMBER 2010 1293
Efficient Load-Aware Routing Scheme
for Wireless Mesh Networks
Kae Won Choi, Wha Sook Jeon, Senior Member, IEEE, and Dong Geun Jeong, Senior Member, IEEE
Abstract—This paper proposes a load-aware routing scheme for wireless mesh networks (WMNs). In a WMN, the traffic load tends to
be unevenly distributed over the network. In this situation, the load-aware routing scheme can balance the load, and consequently,
enhance the overall network capacity. We design a routing scheme which maximizes the utility, i.e., the degree of user satisfaction, by
using the dual decomposition method. The structure of this method makes it possible to implement the proposed routing scheme in a
fully distributed way. With the proposed scheme, a WMN is divided into multiple clusters for load control. A cluster head estimates
traffic load in its cluster. As the estimated load gets higher, the cluster head increases the routing metrics of the routes passing through
the cluster. Based on the routing metrics, user traffic takes a detour to avoid overloaded areas, and as a result, the WMN achieves
global load balancing. We present the numerical results showing that the proposed scheme effectively balances the traffic load and
outperforms the routing algorithm using the expected transmission time (ETT) as a routing metric.
Index Terms—Wireless mesh network, load-aware routing, utility, dual decomposition.
Ç
1 INTRODUCTION
A wireless mesh network (WMN) consists of a number
of wireless routers, which do not only operate as hosts
but also forward packets on behalf of other routers. WMNs
over the traditional hop-count routing metric, they neglect
the problem of traffic load imbalance in the WMN.
In the WMN, a great portion of users intends to
have many advantages over conventional wired networks, communicate with outside networks via the wired gate-
such as low installation cost, wide coverage, and robust- ways. In such environment, the wireless links around the
ness, etc. Because of these advantages, WMNs have been gateways are likely to be a bottleneck of the network. If the
rapidly penetrating into the market with various applica- routing algorithm does not take account of the traffic load,
tions, for example, public Internet access, intelligent some gateways may be overloaded while the others may
transportation system (ITS), and public safety [1]. One of not. This load imbalance can be resolved by introducing a
the main research issues related to WMNs is to develop the load-aware routing scheme that adopts the routing metric
routing algorithm optimized for the WMN. with load factor. When the load-aware routing algorithm is
designed to maximize the system capacity, the major benefit
In mobile ad-hoc networks, the primary concern of
of the load-aware routing is the enhancement of the overall
routing has been robustness to high mobility. However,
system capacity due to the use of underutilized paths.
nodes in the WMN are generally quasi-static in their location. Although there have been some works on load-aware
Thus, the focus of the routing studies in the WMN has moved routing for mobile ad-hoc networks (e.g., [9], [10]) and
to performance enhancement by using sophisticated routing WMNs (e.g., [11], [12], [13]), they simply include some load
metrics [2], [3], [4], [5], [6], [7], [8]. For example, as the routing factors in the routing metric without consideration of the
metrics, researchers have proposed the expected transmis- system-wide performance.
sion number (ETX) [2], the expected transmission time (ETT) In this paper, we propose a load-aware routing scheme,
and weighted cumulative ETT (WCETT) [5], the metric of which maximizes the total utility of the users in the WMN.
interference and channel switching (MIC) [6], and the The utility is a value which quantifies how satisfied a user is
modified expected number of transmissions (mETX) and with the network. Since the degree of user satisfaction
depends on the network performance, the utility can be
effective number of transmissions (ENTs) [8]. Although these
given as a function of the user throughput. Generally, the
metrics have shown significant performance improvement
utility function is concave to reflect the law of diminishing
marginal utility. To design the scheme, we use the dual
. K.W. Choi is with the Department of Electrical and Computer Engineering, decomposition method for utility maximization [14], [16].
University of Manitoba, Room E2-390 EITC Building, 75A Chancellor’s Using this method, we can incorporate not only the load-
Circle, Winnipeg, MB R3T 5V6, Canada. E-mail: kaewon.choi@gmail.com. aware routing scheme but also congestion control and fair
. W.S. Jeon is with the School of Electrical Engineering and Computer rate allocation mechanisms into the WMN. Most notably,
Science, Seoul National University, Gwanak-gu, Seoul 151-742, Korea.
E-mail: wsjeon@snu.ac.kr. we can implement the load-aware routing scheme in a
. D.G. Jeong is with the School of Electronics and Information Engineering, distributed way owing to the structure of the dual
Hankuk University of Foreign Studies, Cheoin-gu, Yongin-si, Gyonggi-do decomposition method.
449-791, Korea. E-mail: dgjeong@hufs.ac.kr. In the proposed routing scheme, a WMN is divided into
Manuscript received 7 Apr. 2008; revised 22 Oct. 2008; accepted 15 Dec. multiple overlapping clusters. A cluster head takes role of
2009; published online 28 Apr. 2010. controlling the traffic load on the wireless links in its cluster.
For information on obtaining reprints of this article, please send e-mail to:
tmc@computer.org, and reference IEEECS Log Number TMC-2008-04-0129. The cluster head periodically estimates the total traffic load
Digital Object Identifier no. 10.1109/TMC.2010.85. on the cluster and increases the “link costs” of the links in the
1536-1233/10/$26.00 ß 2010 IEEE Published by the IEEE CS, CASS, ComSoc, IES, & SPS
2. 1294 IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 9, NO. 9, SEPTEMBER 2010
cluster, if the estimated load is too high. In this scheme, each (ROMER) algorithm in [20] also uses opportunistic for-
user chooses the route that has the minimum sum of the link warding to deal with short-term link quality variation. The
costs on it. Thus, a user can circumvent overloaded areas in ROMER maintains the long-term routes and opportunisti-
the network, and therefore, the network-wide load balance cally expands or shrinks them at runtime.
can be achieved. The works in [21] and [22] focus on the applications
The major advantages of the proposed load-aware accessing the wired gateways. The ad hoc on-demand
routing scheme can be summarized as follows: distance vector spanning tree (AODV-ST) in [21] is an
adaptation of the AODV protocol to the WMN with the
. Designed by the dual decomposition method, the wired gateways. The AODV-ST constructs a spanning tree of
proposed load-aware routing scheme maximizes the which the root is the gateway. In [22], the authors propose a
system-wide performance.
routing and channel assignment algorithm for the multi-
. The proposed scheme is scalable, has low control
channel WMN. In this algorithm, a spanning tree is formed in
and computation overheads, and can be easily
such a way that a node attaches itself to the parent node.
implemented by means of the existing ad hoc
The load-aware routing protocols [9], [10], [11], [12], [13]
routing protocols [17].
incorporate the load factor into their routing metrics. The
The remainder of the paper is organized as follows: In dynamic load-aware routing (DLAR) in [9] takes as the
Section 2, we briefly overview the related works. Section 3 routing metric the number of packets queued in the node
outlines the system model. In Section 4, we formulate the interface. The load-balanced ad hoc routing (LBAR) in [10]
optimization problem and solve it by using the dual counts the number of active paths on a node and its neighbors,
decomposition method. In Section 5, we explain how to and uses it as a routing metric. Both the DLAR and LBAR are
implement the proposed routing scheme in a distributed designed for the mobile ad hoc network, and aim to reduce
way. Section 6 presents the numerical results which show the packet delay and the packet loss ratio. In [11], an
the performance of the proposed scheme. Finally, the paper admission control and load balancing algorithm is proposed
is concluded with Section 7. for the 802.11 mesh networks. In this work, the available radio
time (ART) is calculated for each node, and the route with the
2 RELATED WORKS largest ART is selected when a new connection is requested.
This algorithm tries to maximize the average number of
For the WMN, a number of routing metrics and algorithms
connections. In [12], the authors propose the WCETT load
have been proposed to take advantage of the stationary
balancing (WCETT-LB) metric. The WCETT-LB is the
topology. The first routing metric is the ETX [2], which is the
expected number of transmissions required to deliver a WCETT augmented by the load factor consisting of the
packet to the neighbor. In [3], the authors propose the average queue length and the degree of traffic concentration.
minimum loss (ML) metric which is used to find the route The QoS-aware routing algorithm with congestion control
with lowest end-to-end loss probability. In [4], the medium and load balancing (QRCCLB) in [13] calculates the number
time metric (MTM) is proposed for the multirate network. of congested nodes on each route and chooses the route with
The MTM of a link is inverse proportional to the physical the smallest number of congested nodes.
layer transmission rate of the link. The ETT in [5] is a Compared to these load-aware routing protocols, the
proposed routing scheme has three major advantages. First,
combination of the ETX and the MTM. The ETT is a required
the proposed scheme is design to maximize the system
time to transmit a single packet over a link in the multirate
capacity by considering all necessary elements for load
network, calculated in consideration of both the number of
balancing, e.g., the interference between flows, the link
transmissions and the physical layer transmission rate. The
capacity, and the user demand, etc. On the other hand, the
authors in [5] also suggest the routing metric and algorithm existing protocols fail to reflect these elements since they use
for the multiradio WMN, which are the WCETT and the heuristically designed routing metrics. For example, the
multiradio link quality source routing (MR-LQSR), respec- DLAR, the ART, and the WCETT-LB do not take account of
tively. The WCETT is a modification of the ETT to consider the interference between flows. Also, the link capacity is not
the intraflow interference. While the WCETT only considers considered by the DLAR, the LBAR, the ART, and the
the intraflow interference, the MIC [6] and the interference QRCCLB. Second, the proposed scheme can guarantee
aware (iAWARE) [7] take account of the interflow inter- fairness between users. When the network load is high, it is
ference as well as the intraflow interference. of importance for users to fairly share scarce radio resources.
In [8], the mETX and the ENT are proposed to cope with However, the existing protocols cannot fairly allocate
the fast link quality variation. These routing metrics contain resources, since they are unable to distinguish which route
the standard deviation of the link quality in addition to the is monopolized by a small number of users. Third, the
average link quality. The blacklist-aided forwarding (BAF) proposed scheme can provide routes stable over time. Since
algorithm in [18] is proposed to tackle the problem of short- most of the existing protocols adopt highly variable routing
term link quality degradation by disseminating the black- metrics such as the queue length or the collision probability,
list, i.e., a set of currently degraded links. The ExOR they are prone to suffer from the route flapping problem.
algorithm in [19] decides the next hop after the transmis- We design the proposed routing scheme by using the
sion for that hop without predetermined routes. The ExOR dual decomposition method for the network utility max-
can choose the next hop that successfully received the imization. A brief introduction to this method can be found
packet, and therefore, it is robust to packet error and link in [14], [15], and an elaborate explanation and a number of
quality variation. The resilient opportunistic mesh routing examples can be found in [16]. To use this method, one
3. CHOI ET AL.: EFFICIENT LOAD-AWARE ROUTING SCHEME FOR WIRELESS MESH NETWORKS 1295
TABLE 1
Table of Symbols
Fig. 1. Example mesh network.
should formulate the global optimization problem that is to links in the network, respectively. In Table 1, we summarize
maximize the total system utility under the constraints on all mathematical notations introduced in this section.
the traffic flows and the radio resources. After the The WMN under consideration provides a connection-
constraints are relaxed by the Lagrange multipliers, the oriented service, where connections are managed in the unit
whole problem can be decomposed into the subproblems of a flow. A flow is also unidirectional. A user can
which are solved by the different network layers in the communicate with the other user or the gateway node after
different network nodes. In the decomposed problem, the setting up a flow connecting them. Since a user is connected
Lagrange multipliers act as a interface between the layers to a unique node, the flow between a pair of users can also
and the nodes, enabling the distributed entities to find the be specified by the corresponding node pair. The node
global optimal solution only by solving their own subpro- where a flow starts (ends) will be called the source
blems. Therefore, the dual decomposition method provides (destination) node of the flow. Fig. 1 shows an example
a systematical way to design a distributed algorithm which scenario where a user intends to send data to outside
finds the global optimal solution. networks. As seen in this figure, if a flow conveys data to
(from) outside networks, all gateway nodes can be the
destination (source) node of the flow. We will identify a
3 SYSTEM MODEL flow by an index, generally f, and define F as the set of the
3.1 Mesh Network Structure indices of all flows in the network.
Data traffic on a flow is conveyed to the destination node
Each wireless router in a WMN is fixed at a location. Thus, through a multihop route. We only consider acyclic routes.
the WMN topology does not change frequently and the Thus, a route can be determined by the set of all intermediate
channel quality is quasi-static. In addition, each wireless links that the route takes. We will index a route by r and
router serves so many subscribers (i.e., users) in general that define Dr as the set of the indices of all intermediate links on
the characteristic of the aggregated traffic is stable over time. the route r. For a flow, there can be a number of possible
Therefore, we design the routing scheme under the system routes that connect the source and destination nodes. Fig. 1
model of which topology and user configuration are stable. shows some of the possible routes that a flow can take to
In Fig. 1, we illustrate an example of the WMN. In this send data to the outside networks. Let Gf denote the set of
figure, a node stands for a wireless router, which not only the indices of all possible routes for flow f.
delivers data for its own users, but also relays data traffic for For mathematical development, we assume that a flow can
other wireless routers. Among nodes, there are some utilize multiple routes simultaneously by dividing its data
gateway nodes connected to the wired backhaul network. traffic into these routes. We limit the possible data rate of the
Each user is associated with its serving node. In this paper, traffic conveyed by a flow on each route to control the amount
we do not deal with the interface between a user and its of traffic injected to the WMN. Let f;r denote the “flow data
serving node to focus on the mesh network itself. Through rate” which is defined as the maximum data rate at which the
the serving node, a user can send (receive) data traffic to flow f can send data traffic on the route r. We also define
(from) the other user in the WMN or to (from) outside f :¼ ðf;r Þr2Gf as the “flow data rate vector” of flow f. The
networks via the gateway nodes. If node n can transmit data sum of all the components in a flow data rate vector is limited
to node m directly (i.e., without relaying), there exists a link to the “maximumP flow data rate,” denoted by max . That is, it
from the node n to the node m. In this paper, we define a link should hold that r2Gf f;r max .
as unidirectional. For the mathematical representation, we We will call f the “multipath flow data rate vector,” if
define N and L as the sets of the indices of all nodes and all f;r 0 for more than one r in Gf . On the other hand, we
4. 1296 IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 9, NO. 9, SEPTEMBER 2010
will refer to f as the “single-path flow data rate vector,” if transmission. If two links are adjacent enough to interfere
f;
0 for only one “active route”
and f;r ¼ 0 for the with each other, packets cannot be conveyed through the
other rs in Gf . Since the multipath routing is hard to be two links at the same time. To incorporate this restriction
implemented in a practical sense, we will focus on finding into the proposed scheme, we divide the WMN into
the single-path flow data rate vectors for all flows in the multiple overlapping clusters. A cluster includes the links
WMN. Let
f denote the active route of the flow f that has adjacent enough to interfere with each other. Therefore, any
the single-path flow data rate vector. In case that all flows pair of links in the same cluster cannot deliver packets
simultaneously. A cluster is generally indexed by c, and let
have the single-path flow data rate vector, we can let
:¼
C be the set of the indices of all clusters in the WMN. We
ð
f Þf2F denote the “active route vector.”
also define Mc as the set of all links in the cluster c.
Deciding a single-path flow data rate vector is equivalent
The proposed scheme estimates the traffic load in each
to deciding an active route for the flow and the flow data
cluster. The traffic load in a cluster is the sum of the traffic
rate on the active route. An application using the flow can load on the links in the cluster. If the traffic load in a cluster is
send user data through the active route at its flow data rate. estimated to be too high, the proposed scheme can redirect
The active route can be decided in such a way that the the routes passing through the overloaded cluster for load
global load balancing is accomplished. In addition, network balancing. The airtime ratio of a link represents the traffic
congestion can be controlled and fairness can be guaranteed load on the link. If the sum of the airtime ratios of the links in
by deciding the flow data rate properly. Therefore, the load- a cluster exceeds a certain bound, the cluster can be regarded
aware routing, congestion, and fairness problems can be as overloaded.
solved at the same time, if we find a way to calculate Roughly, we assume that a fixed portion of the time can
appropriate flow data rate vectors. be used for data transmission, while the remainder is used
for the purpose of control, e.g., control message exchange
3.2 Physical and Medium Access Control Layer
and random back-off. Let
5. denote the ratio of the time for
Model
data transmission to the whole time. Since only a link can
The proposed scheme can be implemented on top of convey data traffic at a time within a cluster, the sum of the
various physical (PHY) and medium access control airtime ratios of the links in a cluster cannot exceed
6. .
(MAC) layer protocols that utilize a limited bandwidth Therefore, we have the following constraint:
and divide the time for multiple access, for example, such X
as the carrier sense multiple access/collision avoidance al
7. ; for all c 2 C: ð2Þ
(CSMA/CA), the time division multiple access (TDMA), l2Mc
and the reservation ALOHA (R-ALOHA). In Fig. 1, we give an example organization of clusters.
The effective transmission rate of a link is defined as the Note that we do not draw all clusters to avoid over-
number of actually transmitted bits divided by the time crowding. In this figure, four clusters are presented, each of
spent for data transmission, calculated in consideration of which is indicated by a dashed circle. Suppose that a cluster
retransmissions due to errors. That is, the effective transmis- includes all incoming and outgoing links of the nodes in the
sion rate can be calculated as the PHY layer transmission dashed circle. In this example, the clusters 1 and 2 cover the
rate times the probability of successful transmission. The areas around the gateway nodes 1 and 2, respectively.
PHY layer transmission rate can be fixed, or can be When the estimated traffic load around the gateway node 1
adaptively adjusted according to the channel quality by is too high, the user taking the route to the gateway node 1
means of rate control schemes such as the receiver-based may not achieve high data rate due to the constraint (2) for
autorate (RBAR) [23]. In the WMN under consideration, the cluster 1. In this case, if the gateway node 2 is lightly loaded,
effective transmission rate of a link is assumed to be static for it is desirable for the user to choose the route to the gateway
node 2 for higher data rate. Thus, it can be said that the
a long time due to fixed locations of nodes. We define dl as
traffic load is estimated and controlled in the unit of the
the effective transmission rate of the link l.
cluster for global load balancing.
If all flows convey data traffic through each route at their
The notion of a cluster corresponds to a clique in the
flow data rates, the sum of the data P
P rates of traffic passing
“conflict graph” introduced in [24]. In the conflict graph,
through link l is calculated as r2Hl f2Qr f;r , where Hl is
vertices correspond to the links in the WMN. An edge is
defined as the set of the indices of all routes passing through
drawn between two vertices if the corresponding links
the link l, i.e., Hl :¼ fr : l 2 Dr g, and Qr is the indices of all interfere with each other. Thus, an edge stands for confliction
flows that use the route r, i.e., Qr :¼ ff : r 2 Gf g. We define between two vertices. A clique in the conflict graph is a set of
the “airtime ratio” of the link l, denoted by al , as the ratio of vertices that mutually conflict with each other. According to
the time taken up by the transmission to the total time of link [24], unless the conflict graph is a “perfect graph,” the clique
l. The airtime ratio of the link l can be calculated as the sum of constraints in (2) are not tight in the strict sense even when all
the data rates on the link l divided by the effective cliques (clusters) are taken into account. In [25], the authors
transmission rate of the link l. That is, propose the centralized algorithm that transforms the conflict
X X f;r graph to a perfect graph by adding unnecessary edges to the
al ¼ : ð1Þ conflict graph. This algorithm can also be applied to our
r2Hl f2Q
dl
r
routing scheme. However, from a practical point of view, this
Now, we discuss the restriction on the radio resource algorithm is inefficient since it requires centralized control
allocation. For the protocols under consideration, time is the and can overly reduce spatial reuse. Therefore, in this paper,
only radio resource, which is shared by links for data we recommend to use the clique constraints in (2) as it is.
8. CHOI ET AL.: EFFICIENT LOAD-AWARE ROUTING SCHEME FOR WIRELESS MESH NETWORKS 1297
À1
Actually, these clique constraints are enough to serve our duf ðxÞ
¼ xþ1 : ð5Þ
purpose, i.e., identifying overloaded regions in the WMN to dx pf
redirect the routes. Also, there can be too many cliques in the
The marginal utility of a flow is the amount of the utility that
conflict graph, and therefore, considering all of them can
the system can obtain by assigning a unit data rate to the
render the proposed scheme highly complex. From a practical
flow. Thus, to maximize the system utility, the proposed
point of view, the clusters do not need to cover all possible scheme is likely to allocate more data rate to the flow with
cliques, but it is enough for the clusters to be formed in such a large marginal utility. If is large, the marginal utility drops
way that the traffic load in each region of the WMN is quickly as the data rate increases. In this case, the data rates
separately evaluated. tend to be fairly allocated to flows, since the incentive to
3.3 Utility and Delay Penalty as Optimization Target assign more data rate to the flow which has already received
a high data rate reduces. The flow with large value of pf has
The flow with longer distance consumes generally more
a large marginal utility, and therefore, it can receive more
airtime to convey the same amount of data. Therefore, if
data rate.
maximizing system throughput is the optimization target in
the WMN, the flows with short distance are likely to be When the flowP sends data at its flow data rate, the data
f P
allowed to send much more data than those with long rate of flow f is r2Gf f;r . Note that r2Gf f;r is equal to
distance are, which leads to unfair resource allocation among the data rate allocated to one active route, if f is a single-
flows. Thus, we need an optimization target other than the path flow data rate vector. Hence, the utility of flow f is
P
system throughput to take into account the fairness among uf ð r2Gf f;r Þ. If we consider only the utility in the objective
flows. We consider the utility of a flow that represents the function of the optimization problem, the routing algorithm
degree of satisfaction felt by the user using the flow. The is likely to ignore the end-to-end delay on a route. Since the
utility is a highly desirable performance measure since the delay is also of great importance in the practical WMN, we
user satisfaction is the ultimate goal of the network design. incorporate the delay term into the objective function. To do
The utility function defines the mapping between the this, we define the “delay penalty function” for each flow,
data rate of a flow and the utility of that flow. Since the which penalizes the objective function for selecting the
utility function quantifies the network performance per- route with long end-to-end delay. Since the time to transmit
ceived by users when a data rate is given, it can only be a packet of x bits through the link l is given as x=dl , we can
estimated by a subjective survey, not by theoretical
sayP the end-to-end delay on the route r is proportional
that
development. In [26] and [27], the utility function for best
to l2Dr 1=dl . The delay penalty function should have a
effort traffic is derived by analyzing the results from a
subjective survey for various network data applications. larger value when a flow sends more data on the route with
The utility function of a single best effort user is given as long end-to-end delay. Therefore, the delay P
P penalty func-
tion for the flow f can be given as r2Gf f;r l2Dr 1=dl .
uðxÞ ¼ 0:16 þ 0:8 lnðx À 3Þ; ð3Þ Since we have two different objectives (i.e., the utility and
the delay penalty), we should find a Pareto optimal solution
where x is the data rate in the unit of Kilobits per second.
such that no other solution can improve any objective
This utility function is a strictly concave function, and as a
without worsening the other objective. To calculate a Pareto
result, it well shows the law of diminishing marginal utility.
Although the utility function (3) might be best fitted to optimal solution, we use the scalarization technique [28,
the survey results, it is not adequate for theoretical pp. 178-180] that merges multiple objectives into a single
derivation since it is not defined for x 3. Thus, we do objective by taking the weighted sum of the objectives. We
not take the specific values in (3) but adopt only the log introduce the merged objective function as follows:
form of (3) to reflect the law of diminishing marginal utility. 0 1
In this paper, the utility function is designed so as to contain X X XX X 1
the parameters related to system-wide fairness and priority OðÞ :¼
uf @ f;r A À Á f;r ; ð6Þ
f2F r2G f2F r2G l2D
dl
of flows. We define the utility function of flow f as follows: f f r
where :¼ ðf;r Þf2F ;r2Gf and is the “delay penalty para-
pf
uf ðxÞ :¼ ln xþ1 ; ð4Þ meter” that controls the relative importance of the delay
pf
penalty to the utility. We can reduce the end-to-end delay at
where x is the data rate, is the system-wide fairness the expense of the utility by increasing the delay penalty
parameter, and pf represents the priority of flow f. The
parameter. We will demonstrate the impact of the delay
utility function enables us to control the trade-off between
efficiency and fairness by adjusting . With a high value of penalty parameter in Section 6.
, the system-wide fairness can be guaranteed at the cost of
the system throughput. In other words, by increasing the 4 PROPOSED LOAD-AWARE ROUTING SCHEME
value of , the standard deviation of the flow data rates can
be decreased, but the average flow data rate also decreases. In this section, we design the proposed routing scheme by
The parameter pf controls the priority of flow f. The flow using the dual decomposition method. We first formulate the
with high priority pf is likely to enjoy a high data rate. optimization problem from the objective function and the
To explain the reason behind the effect of the parameters, constraints introduced in the previous section, and derive
we introduce the marginal utility. The marginal utility can the dual problem. Next, we explain how to calculate the flow
be derived by differentiating the utility function by the data data rate vector for the given Lagrange multipliers and
rate. That is, suggest the subgradient method to iteratively calculate the
9. 1298 IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 9, NO. 9, SEPTEMBER 2010
X
optimal Lagrange multipliers. Finally, we propose the s:t: l À c ¼ 0; for l 2 L; ð13Þ
c2V l
dampening algorithm to alleviate the route flapping problem.
c ! 0; for c 2 C: ð14Þ
4.1 Problem Formulation
à à Ã
We formulate the optimization problem from (1), (2), and Let w :¼ ð ; Þ be any optimal solution of this dual
problem.
(6) as follows:
! 4.2 Flow Data Rate Calculation for Given Lagrange
X X XX X1
max uf f;r À Á f;r ; ð7Þ Multipliers
f2F r2Gf f2F r2Gf
d
l2Dr l Now, we calculate the flow data rates that maximize the
X X f;r Lagrangian (10) for given Lagrange multipliers. To do this,
s:t: al ¼ ; for all l 2 L; ð8Þ
r2Hl f2Qr
dl we find the maximizer of ð f ; Þ over f 2 P f for each flow
X f. Let P f ðÞ denote the set of such maximizers, i.e.,
al
10. ; for all c 2 C; ð9Þ P f ð Þ :¼ arg maxf 2P f ð f ; Þ. The following proposition
l2Mc
holds for the set P f ðÞ:
P
where f;r ! 0 and r2Gf f;r max for all f and r. This Proposition 1. The set P f ð Þ contains at least one single-path
optimization problem is feasible and convex. Let à be any
f;r flow data rate vector.
optimal solution of this optimization problem. We also
Proof. The proof is provided in Appendix A. u
t
define the optimal flow data rate vector à :¼ ðà Þr2Gf .
f f;r
We solve the optimization problem by converting it to
From now on, we will explain how to find a single-path
the dual problem according to the Lagrangian method in
flow data rate vector in P f ðÞ. Let f ð
; Þ be the maximum
[29]. The Lagrangian is given as follows:
value of ðf ; Þ when f is a single-path flow data rate
Âð; a; wÞ
vector with the active route of
. That is,
!
X X XX
X1 X þ l '
:¼ uf f;r ÀÁ f;r f ð
; Þ :¼ max uf ðÞ À : ð15Þ
d 0 max dl
f2F r2Gf f2F r2Gf l2Dr l l2D
X X X f;r ' X X '
þ l al À þ c
11. À al We define Rf ðÞ :¼ arg max
2Gf f ð
; Þ as the set of the
l2L r2Hl f2Qr
dl c2C l2Mc ð10Þ “optimal routes.” To maximize ðf ; Þ, the active route
!
X X X X þ l ' should be one of the optimal routes in Rf ðÞ. Since uf ðÞ is
¼ uf f;r À f;r a concave function, f ð
; Þ is larger for the active route
P
f2F r2Gf r2Gf l2Dr
dl with the smaller l2D
l =dl . Therefore, we can also write
X X ' X Rf ð Þ as follows:
þ l À c a l þ
12. c ;
l2L c2V l c2C
X þ l
Rf ð Þ ¼ arg min
: ð16Þ
2Gf dl
where a :¼ ðal Þl2L and V l denotes the set of the indices of all l2D
clusters that the link l belongs to (i.e., V l :¼ fc : l 2 Mc g). It
is noted that we have P We define ð þ l Þ=dl as the “link cost” of the link l. Since
l2D
ð þ l Þ=dl is the sum of link costs on the route
, the
X XX XX X optimal route is the route that minimizes the sum of link
l f;r =dl ¼ f;r l =dl ;
l2L r2Hl f2Qr f2F r2Gf l2Dr
costs. Since most existing ad hoc routing algorithms can
P P P P employ the sum of link costs as the routing metric, the
and c2C c l2Mc al ¼ l2L al c2V l c . In (10), l and c optimal route can be found by applying those ad hoc
are the Lagrange multipliers corresponding to the con- routing algorithms.
straints (8) and (9), respectively. We also define :¼ ðl Þl2L , When f is a single-path flow data rate vector with the
:¼ ðc Þc2C , and w :¼ ð ; Þ.
active route of
, we can maximize ðf ; Þ if the flow data
From the Lagrangian, we define the dual function as rate on the active route is equal to
gðwÞ :¼ max;a Âð; a; wÞ. The dual function gðwÞ is defined
P f ð
; Þ
only for the Lagrange multipliers such that l À c2V l c ¼ X þ l '
0 for l 2 L, since we have gðwÞ ¼ 1 for the other Lagrange :¼ arg max uf ðÞ À
multipliers. Then, the dual function is given as follows: 0 max
l2D
dl ð17Þ
X X !þ '
pf 1
gðwÞ ¼ max ð f ; Þ þ
13. c ; ð11Þ ¼ min P À1 ; max ;
l2D
ð þ l Þ=dl
f 2P f
f2F c2C
P
where P f :¼ ff : f;r ! 0 for r 2 Gf ; r2Gf f;r max g and
w h e r e ½xŠþ ¼ maxf0; xg. L e t u s d e f i n e f ð
; Þ :¼
P P P
ðf ; Þ :¼ uf ð r2Gf f;r Þ À r2Gf f;r l2Dr ð þ l Þ=dl .
ðf;r ð
; ÞÞr2Gf as follows:
From the dual function, we define the following dual
f ð
; Þ; if r ¼
;
problem: f;r ð
; Þ ¼ ð18Þ
0; otherwise:
min gðwÞ; ð12Þ
Then, we have f ð
; Þ 2 P f ðÞ if
2 Rf ð Þ.
14. CHOI ET AL.: EFFICIENT LOAD-AWARE ROUTING SCHEME FOR WIRELESS MESH NETWORKS 1299
ðjÞ
4.3 Lagrange Multiplier Update jP f ðà Þj 1, it is not guaranteed that f ð
f ; ðjÞ Þ converges
From now on, we will find the solution of the dual problem to the optimal flow data rate vector. The cardinality of
(12). The constraint (13) in the dual problem can be P f ð Ã Þ is closely related to the cardinality of Rf ð Ã Þ in (16).
incorporated into the dual function. We define the modified If jRf ð Ã Þj ¼ 1, we also have jP f ð Ã Þj ¼ 1. On the other
dual function hð Þ :¼ gðð ðÞ; ÞÞ, where ð Þ :¼ ðl ðÞÞl2L
hand, if jRf ðà Þj 1, the set P f ðÃ Þ contains multiple flow
satisfies the constraint (13) for given . That is, data rate vectors, which include the multipath flow data
X rate vector distributing the data rates on the multiple routes
l ð Þ ¼
c ; ð19Þ in Rf ð à Þ. This means that à may be the multipath flow
f
c2V l data rate vector for the flow f such that jRf ðà Þj 1. In this
ðjÞ
for all l. Then, the dual optimal solution à minimizes hðÞ
case, the single-path flow data rate vector f ð
f ; ðjÞ Þ
over c ! 0 for all c 2 C. cannot converge to à . However, we can still use
f
ðjÞ
We will use the subgradient method [29, p. 620] to f ð
f ; ðjÞ Þ for all fs as a suboptimal solution very close
calculate the dual optimal solution. We can calculate the to the optimal one, since there are generally a small number
subgradients of h from the theorem of dual derivatives [29, of the flows fs such that jRf ð Ã Þj 1, and the flow data
p. 604]. Recall that
f denotes the active route of the flow f, rates in P f ð Ã Þ well approximate à even for fs such that
f
and
¼ ð
f Þf2F denotes the active route vector. We first
jRf ð Ã Þj 1.
ðjÞ
calculate al ð ; Þ, which denotes the airtime ratio of link l
Even when we use f ð
f ; ðjÞ Þ as a suboptimal solution,
when
and are given. The airtime ratio al ð ; Þ is
we still have the “route flapping problem.” The fact that
ðjÞ
calculated as follows: f ð
f ; ðjÞ Þ converges to the set P f ðÃ Þ does not mean
ðjÞ
that f ð
f ; ðjÞ Þ has a limit in P f ð Ã Þ. Therefore, for fs such
X X f;r ð
f ; Þ ðjÞ
al ð ; Þ :¼
: ð20Þ that jP f ð Ã Þj 1, it is possible that f ð
f ; ðjÞ Þ alternates
r2Hl f2Qr
dl between some points in P f ðÃ Þ even after ðjÞ is sufficiently
converged to à . In this case, the active route can flap between
From al ð ; Þ, we can calculate sð ; Þ :¼ ðsc ð ; ÞÞc2C ,
some routes in Rf ð Ã Þ. We now suggest the “dampening
which is defined as
algorithm” to solve this route flapping problem.
X
sc ð ; Þ :¼
15. À
al ð ; ðÞÞ:
ð21Þ
4.5 Dampening Algorithm: Solution to Route
l2Mc
Flapping Problem
If
f 2 Rf ððÞÞ for all f 2 F , the vector sð ; Þ is the
The dampening algorithm should alleviate the route flapping
subgradient of hðÞ. problem while keeping the solution in the close range of the
Let ðjÞ :¼ ððjÞ Þc2C be the estimation of à at the jth
c optimal one. Moreover, the dampening algorithm should be
iteration of the subgradient method. We also define
ðjÞ :¼ able to be implemented in a distributed way. To accomplish
ðjÞ ðjÞ
ð
f Þf2F as the active route vector such that
f 2 Rf ðððjÞ ÞÞ
these goals, the dampening algorithm prevents the route
for all f 2 F . The iteration begins when j ¼ 1. The initial flapping by changing the active route more conservatively
values should satisfy ð0Þ ! 0 for all c 2 C. The Lagrange
c than the original algorithm does. When the original algo-
ðjÞ
multipliers are updated at the jth iteration as follows: rithm is used, we have
f 2 Rf ð ðjÞ Þ. This means that, at the
 À ÁÃþ jth iteration, the original algorithm finds any optimal route in
ðjþ1Þ ¼ ðjÞ À ðjÞ s
ðjÞ ; ðjÞ
; ð22Þ Rf ð ðjÞ Þ from (16), and immediately changes the active route
to the new optimal route. However, the dampening algo-
where ½ðxc Þc2C Šþ ¼ ðmaxf0; xc gÞc2C and ðjÞ is the step size.
rithm changes the active route only if the new route increases
The step size can be the diminishing step size that satisfies
P1 ðjÞ P1 ðjÞ 2 f ð
; ðjÞ Þ by a certain margin.
ðjÞ 0, j¼0 ¼ 1, and j¼0 ð Þ 1. In this case, Let us explain the operation of the dampening algorithm.
ðjÞ converges to à . Alternatively, we can also use the We define as the “dampening parameter” which controls
constant step size, which makes ðjÞ converge to within the conservativeness in changing the route. The value of is
ðjÞ
some range of à . We define ðjÞ :¼ ðl Þl2L ¼ ððjÞ Þ. Then,
between zero and one. If is set to one, the dampening
ðjÞ converges to à when ðjÞ converges to à . algorithm is the same as the original algorithm. The active
route is changed more conservatively with the smaller value
4.4 Convergence of Flow Data Rate
ðjÞ of . At the jth iteration, the dampening algorithm first finds
We take f ð
f ; ðjÞ Þ as the estimation of the optimal flow ðjÞ
any optimal route in Rf ð ðjÞ Þ. Let yf denote the optimal route
data rate vector à at jth iteration. We will discuss the
f for the flow f, newly found at the jth iteration. The
convergence of this flow data rate vector. Since the ðjÞ
dampening algorithm decides the active route
f according
optimization problem (7) is strictly feasible and the objective
to the following rules:
and constraint functions are concave, the strong duality
ðjÀ1Þ ðjÞ
holds from the Slater’s constraint qualification [29, p. 520]. . If f ð
f ; ðjÞ Þ ! Á f ðyf ; ðjÞ Þ, the dampening
Therefore, Ã is included in the set P f ð Ã Þ. Moreover,
f algorithm does not change the active route, i.e.,
ðjÞ
f ð
f ; ðjÞ Þ also converges to the set P f ð Ã Þ as j ! 1, since
ðjÞ ðjÀ1Þ
ðjÞ
f ¼
f .
we have f ð
f ; ðjÞ Þ 2 P f ð ðjÞ Þ for all j.
ðjÀ1Þ ðjÞ
From the above statements, we can conclude that . If f ð
f ; ðjÞ Þ Á f ðyf ; ðjÞ Þ, the dampening
ðjÞ algorithm changes the active route to the new
f ð
f ; ðjÞ Þ converges to à as j ! 1 for the flow f such
f ðjÞ ðjÞ
that jP f ð Ã Þj ¼ 1. However, for the flow f such that
optimal route, i.e.,
f ¼ yf .
16. 1300 IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 9, NO. 9, SEPTEMBER 2010
Consequently, the dampening algorithm can alleviate the Theorem 1. If the dampening algorithm is used, we have ½jðjÞ À
route flapping problem if the dampening parameter is set à j À ðÞŠþ ! 0 as j ! 1, where ðÞ :¼ maxfj À à j :
to a sufficiently small value. The stability comes at the cost Á hðÞ hð Ã Þg.
of the suboptimal route selection. For all j, the suboptimal Proof. The proof is provided in Appendix B. u
t
ðjÞ
route
f satisfies the following condition:
À ðjÞ Á According to Theorem 1, ðjÞ converges to within the
f
f ; ðjÞ ! Á max f ð
; ðjÞ Þ: ð23Þ distance of ðÞ from à . If we set to a smaller value to
2Gf
make the WMN more stable, the Lagrange multipliers
Except for the difference in deciding
ðjÞ , the dampening
deviate more from à , since ðÞ becomes larger for the
algorithm uses the same equations (17)-(22) as the original smaller . Additionally, for the given Lagrange multipliers,
algorithm to calculate the flow data rate vectors and update the dampening algorithm selects the suboptimal route that
the Lagrange multipliers. satisfies the condition in (23). Therefore, we can conclude
Now, we discuss the property of the dampening that the dampening algorithm finds the suboptimal solu-
algorithm. For the given active route vector
¼ ð
f Þf2F ,
tion, to which the distance from the optimal solution is
we define the “fixed-route optimization problem” as the restricted by the condition in (23) and Theorem 1.
modified version of the optimization problem (7) in such a Though it is verified in Theorem 1 that ðjÞ converges to a
way that the flow data rate vector of flow f is restricted to certain range of à , we cannot guarantee that ðjÞ has a limit
the single-path flow data rate vector with the active route of within the range. However, ðjÞ can have a limit, if the
f for all fs in F . Let hð ; Þ denote the dual function of the
following condition is met. Suppose that the dampening
fixed-route optimization problem with the active route algorithm selects a certain active route vector
à :¼ ð
f Þf2F
Ã
ðjÞ Ã
vector of
. The dual function hð ; Þ is given as
at the Jth iteration. It is possible that
¼
for j ! J, if
X X we have f ð
f ; ðjÞ Þ ! Á max
2Gf f ð
; ðjÞ Þ for all f 2 F for
Ã
hð ; Þ :¼
f ð
f ; ðÞÞ þ
17. c : ð24Þ j ! J. There can be
à satisfying the above condition, if is
f2F c2C sufficiently small. Let à ð Þ denote the optimal Lagrange
multiplier of the fixed-route optimization problem with the
The following propositions hold for the dual function
active route vector of
. From Proposition 4, the Lagrange
hð ; Þ:
multiplier ðjÞ approaches à ð ðjÞ Þ at the jth iteration.
Proposition 2. hðÞ ¼ max
hð ; Þ.
Therefore, ðjÞ has a limit on à ð à Þ, if we have
ðjÞ ¼
Ã
ðjÞ
Proof. From Proposition 1, the single-path flow data rate for j ! J. Accordingly, f ð
f ; ðjÞ Þ also converges to the
vector can be a maximizer of ðf ; ð ÞÞ. Therefore, it
optimal solution of the fixed-route optimization problem
holds that with the active route vector of
à . In this case, we can
X X guarantee the lower bound on the performance of the
hðÞ ¼
max f ð
; ðÞÞ þ
18. c dampening algorithm as stated in the following theorem:
2Gf
f2F c2C
Theorem 2. Suppose that there exist
à and J such that
ðjÞ ¼
( )
X X
à for j ! J. Then, we have the lower bound on the
¼ max f ð
f ; ðÞÞ þ
19. c ¼ max hð ; Þ:
performance of the dampening algorithm as follows:
f2F c2C
t
u lim Oðð ðjÞ ; ðjÞ ÞÞ ! Á Oðà Þ;
ð25Þ
j!1
where à :¼ ðà Þf2F ;r2Gf , ð ; Þ :¼ ðf;r ð
f ; ÞÞf2F ;r2Gf ,
f;r
Proposition 3. hð ðjÞ ; ðjÞ Þ ! Á hððjÞ Þ for all j.
and OðÞ is the objective function defined in (6).
P ðjÞ
Proof. For all j, we have hð ; ðjÞ Þ ¼ f2F f ð
f ; ðjÞ Þ þ
ðjÞ
Proof. The proof is provided in Appendix C. u
t
P P ðjÞ P
21. c2C ðjÞ !
c c
Á hððjÞ Þ.
u
t 5 DISTRIBUTED IMPLEMENTATION
Proposition 4. sð ; Þ is the subgradient of hð ; Þ.
The proposed routing scheme can be implemented in a
Proof. When is given, f ð
f ; ðÞÞ is the maximizer of the
distributed way, which improves the scalability of the
Lagrangian of the fixed-route optimization problem with WMNs. In this section, we discuss the distributed
the active route vector of
. Therefore, sð ; Þ is the
implementation of the proposed scheme. The flow data
ðjÞ
subgradient of the dual function of this optimization rate vectors f ð
f ; ðjÞ Þs and the Lagrange multipliers ðjÞ s
c
problem from the theorem of dual derivatives. u
t are distributively managed by the nodes in the WMN. The
ðjÞ
flow data rate vector f ð
f ; ðjÞ Þ is managed by the source
ðjÞ
From Proposition 4, the Lagrange multipliers are node of the flow f. Recall that f ð
f ; ðjÞ Þ is the single-path
ðjÞ
updated at the jth iteration, not by using the subgradient flow data rate vector with the active route of
f , and the
of hð ðjÞ Þ but by using the subgradient of hð ðjÞ ; ðjÞ Þ, since
ðjÞ ðjÞ ðjÞ
flow data rate on
f is equal to f ð
f ; Þ. Therefore, the
ðjÞ
f may not included in Rf ððjÞ Þ. In the dampening
source node of the flow f actually manages
f and
ðjÞ
ðjÞ ðjÞ
algorithm, the Lagrange multipliers converge to within a f ð
f ; Þ.
certain range of the optimal Lagrange multiplier as stated in For implementation, one node within a cluster is desig-
the following theorem: nated as the head of the cluster. The head of a cluster is
22. CHOI ET AL.: EFFICIENT LOAD-AWARE ROUTING SCHEME FOR WIRELESS MESH NETWORKS 1301
By the above steps, not only the routing but also the link
cost control and the flow control are performed. That is,
. Each cluster head estimates the traffic load within
P
the cluster, that is,
ðjÞ ðjÞ
l2Mc al ð ; Þ for cluster c,
and the nodes within the cluster adjust the link costs
ðjÞ
of its outgoing links, ð þ l Þ=dl for link l, on the
basis of this estimated load as in steps 1-5 (i.e., link
cost control).
. Based on the link costs, the active route for each flow
is updated in steps 6-8 (i.e., routing).
. The flow data rate is calculated in step 9 (i.e., flow
control).
Theoretically, an operation can be performed only after
the preceding operation has been completed. In this case,
however, the proposed scheme may converge very slowly.
When the dual decomposition method is used, different
variables can be updated according to the different time
schedules [15]. Therefore, in order to improve the conver-
gence speed, in practice, different network entities (i.e.,
cluster heads, nodes in each cluster, and source nodes) carry
out these operations asynchronously, by using currently
Fig. 2. Control information exchange for distributed implementation. available information. Though it is difficult to prove that
the asynchronous operation leads to the exact solution, we
assumed to be able to communicate with the transmitter have confirmed by the simulation that the solutions
nodes of the links in its cluster. Let us call the head of cluster c produced by the asynchronous and the synchronous opera-
the “cluster head” c. The cluster head c takes the role of tions are the same in our routing problem. In the following,
maintaining and updating ðjÞ . we describe three operations in more detail when they are
c
The proposed scheme takes the following steps at the jth implemented asynchronously.
iteration of the subgradient method. Fig. 2 illustrates an . Link cost control: For link cost control, the cluster head
example of control information exchange for this operation. c gathers the information on the total load in the
cluster c and adjusts c to control the load on the
1. The source node of flow f sends a message contain-
ðjÞ ðjÞ cluster c. This process is as follows: Each node
ing f ð
f ; ðjÞ Þ to the nodes on the active route
f .
estimates the total loads for all outgoing links and
2. Each node calculates al ð ðjÞ ; ðjÞ Þs for its all outgoing
broadcasts the estimated loads periodically as in step 2.
links from (20) and broadcasts them to the heads of Upon receiving the broadcasting message, the cluster
clusters to which the links belong. head can compute the total airtime ratio consumed by
3. The cluster head c receives al ð ðjÞ ; ðjÞ Þs for all links
the links in its cluster. If the total airtime ratio exceeds
in its cluster and updates ðjÞ to ðjþ1Þ from (22).
c c the available airtime ratio (i.e.,
23. ), it means that the
4. The cluster head c broadcasts ðjþ1Þ to the transmit-
c cluster is overloaded. Therefore, the cluster head c
ter nodes of the links in its cluster. increases c as in step 3. If the cluster c is not
ðjþ1Þ
5. Each node calculates l ¼ l ððjþ1Þ Þ from (19) and
overloaded, that is, its total airtime ratio is smaller
ðjþ1Þ
derives the link cost ð þ l Þ=dl for its all outgoing than
24. , the cluster head c decreases c . The cluster
links. head c periodically broadcasts c as in step 4. From
6. The source node of flow f finds the optimal route this broadcasting message, f þ l ðÞg=dl s are calcu-
ðjþ1Þ
yf 2 Rf ððjþ1Þ Þ. An implementation example for
lated for all links within the cluster as in step 5. Since
finding the optimal route, when each node main- l ðÞ is the sum of c s for the clusters around the link l
tains the updated link costs for its all outgoing links, (see (19)), the link cost of the link l (i.e., f þ l ð Þg=dl )
will be explained later. can be controlled by the cluster heads based on the
7. The source node of flow f is informed of the link inflicted load.
ðjþ1Þ ðjÞ
costs ð þ l Þ=dl s on the current active route
f . Routing: The link cost of link l is calculated as
ðjþ1Þ
and the new optimal route yf . f þ l ðÞg=dl . Since dl is the effective transmission
ðjþ1Þ ðjþ1Þ
8. The source node of flow f sets
f to yf , if it rate reflecting the PHY transmission rate as well as
holds that the packet error probability, we can say that 1=dl is
À ðjÞ Á À ðjþ1Þ Á equivalent to the ETT in [5]. Therefore, the link cost in
f
f ; ðjþ1Þ Á f yf ; ðjþ1Þ : the proposed scheme can be viewed as the ETT
augmented with the load control variable (i.e., l ðÞ).
If not, the active route is not changed, i.e., To find the optimal route on which the sum of the
ðjþ1Þ ðjÞ
f ¼
f . proposed link cost is minimized, we can use either the
9. The source node of flow f calculates the flow data existing proactive routing protocols (e.g., the destina-
ðjþ1Þ
rate f ð
f ; ðjþ1Þ Þ from (17). tion-sequenced distance vector (DSDV)) or reactive
25. 1302 IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 9, NO. 9, SEPTEMBER 2010
routing protocols (e.g., the AODV and the dynamic TABLE 2
source routing (DSR)). The source node of flow f Table of Simulation Parameters
periodically finds the new optimal route yf by using
these routing protocols as in step 6. The source node is
aware of the link costs on the current active route
from the periodic report, and is also informed of the
link costs on the new optimal route by the routing
protocol (step 7). Based on these link costs, the source
node decides whether to change the active route or
not as in step 8.
. Flow/congestion control: As in step 9, the source node
periodically recalculates the flow data rate f ð
f ;
ð ÞÞ by using the link costs on the active route
according to (17). As seen from (17), the source node
lowers the flow data rate when the link costs on
the active route is high. Since the source node limits
the data rate of its traffic to the flow data rate, the
source node can be quenched when the active route Let us explain the organization of clusters. We organize
passes through the congested area of the network. clusters based on the following two rules, which define the
interfering relationship between links. First, all incoming
By the above three operations, network-wide load
and outgoing links of a node interfere with each other. This
balance can be achieved. If an area of the network is
is because a node cannot receive or transmit data through
overloaded, the link costs around the area are increased by
more than one link at the same time. Second, two links
the link cost control operation. Then, the source node of the
interfere with each other, if the transmitter or receiver node
flow passing through the area reduces its flow data rate, or
of one link is within the interfering range of the transmitter
finds another route that allows a higher flow data rate.
or receiver node of the other link. This can be exemplified
Fig. 2 illustrates an example of control information
by the IEEE 802.11 protocol, in which the transmitter node
exchange for a flow and a cluster. On the active route
f , the sends a request-to-send (RTS) packet and the receiver node
flow data rate f ð
f ; ðÞÞ and the link cost f þ l ð Þg=dl are
responds with a clear-to-send (CTS) packet to prevent the
exchanged. This control information can be piggybacked on nodes close to the transmitter or receiver node from
the data and acknowledgement (ACK) packets. In addition, interfering with packet transmission. On the basis of these
the airtime ratio al ð ; ðÞÞ and the Lagrange multiplier c are
rules, we organize clusters as follows: for each pair of nodes
exchanged between the cluster head and nearby nodes. If the m and n within the interfering range of each other, there is a
proposed scheme is applied to the systems broadcasting the cluster including all the incoming and outgoing links of
beacon message periodically, for example, such as IEEE the nodes m and n. We assume that two nodes are within
802.11, 802.15.3, and 802.15.4 standards, this information can the interfering range of each other, if the received SNR at a
also be conveyed by these beacon messages without addi- node from the other node is over À7 dB.
tional control packet transmission. It is assumed that the ratio of the time dedicated to data
transmission (i.e.,
26. ) is 0.8. The maximum flow data rate
(i.e., max ) is set to 100 Mbps. The system-wide fairness
6 NUMERICAL RESULTS parameter in the utility function (i.e., ) is set to 1, unless
The numerical results presented below show that the noted otherwise. The priority of flow f (i.e., pf ) is set to 1 for
proposed routing scheme effectively balances traffic load, all flows. For the subgradient method, the step size (i.e., ðjÞ )
and consequently, outperforms the routing algorithm using is set to 0.01. Unless noted otherwise, the delay penalty
the ETT as a routing metric. parameter (i.e., ) is set to 1, and the dampening parameter
(i.e., ) is set to 0.95.
6.1 Environments and Parameters for Numerical
We do not assume any specific PHY/MAC layer
Results
protocol. Instead, we assume that the WMN uses a simple
We first describe the environment and parameters for getting reservation protocol (e.g., the mesh deterministic access
the numerical results. In Table 2, we summarize the (MDA) of the 802.11s protocol [30]). The WMN first
simulation parameters. We consider 8 km  8 km square calculates the required amount of time for each link to
area. There are 300 nodes, which are randomly located support the flow data rates of the flows on it. After that, it
according to the uniform distribution. The network uses the assigns the calculated amount of time to each link by using
bandwidth of 20 MHz. The transmission power of a node is a reservation protocol. Each flow on a link reserves a
24.5 dBm, and the noise density is assumed to be À163 dBm/ portion of the time assigned to the link. Then, each flow has
Hz. We assume the line-of-sight (LOS) link between nodes. an end-to-end path with a reserved data rate. We assume
Therefore, for the channel fading model, we only consider the that a flow has an infinite backlog and sends data at its flow
path loss calculated as xÀ3:7 , where x is the distance between data rate through its end-to-end path. In this setting, we can
nodes in meters. A link is established between two nodes if estimate the throughput of each flow from the reserved data
the signal-to-noise ratio (SNR) between them exceeds 0 dB. rate of its end-to-end path. In this paper, we do not use an
The effective transmission rate of link l (i.e., dl ) is assumed to event-based simulator since it is not necessary to simulate
be the Shannon capacity of the link. That is, dl ¼ 20 Â log2 ð1 þ the behavior of individual packets for estimating the
SNRl Þ Mbps, where SNRl is the SNR of the link l. throughput of each flow.