This paper proposes a fair and efficient QoS scheduling scheme for IEEE 802.16 BWA systems that
satisfies both throughput and delay guarantee to various real and non-real time applications. The proposed
QoS scheduling scheme is compared with an existing QoS scheduling scheme proposed in literature in
recent past. Simulation results show that the proposed scheduling scheme can provide a tight QoS
guarantee in terms of delay, delay violation rate and throughput for all types of traffic as defined in the
WiMAX standard, thereby maintaining the fairness and helps to eliminate starvation of lower priority
class services. Bandwidth utilization of the system and fairness index of the resources are also
encountered to validate the QoS provided by our proposed scheduling scheme.
Call Admission Control Scheme With Multimedia Scheduling Service in WiMAX Net...Waqas Tariq
WiMAX network introduces a multimedia data scheduling service with different quality of service (QoS) requirements. Transmission opportunities are scheduled by the service according to the types of traffic data for the different connections or users. In the paper, we first propose a uniform definition of QoS level for the multimedia data types in the service. The QoS level of a connection are determined by the type of data of the connection and its allocated resources. Based on these QoS levels, we propose a call admission control (CAC) scheme for the entry admission of a new connection without degrading the network performance and the QoS of ongoing connections. The key idea of this scheme is to regulate the arriving traffic of the network such that the network can work at an optimal point, given under a heavy load traffic. Taking advantage of the simulation experiments, we confirm the fact that the proposed scheme can achieve better trade-off between the overall performance of network system and the QoS level of individual connection.
Modulation aware connection admission control and uplink scheduling algorithm...ijwmn
Mobile WiMAX standard defines air interface for mobile broadband wireless access (BWA) systems and aimed to provide high data rate with seamless mobility while maintaining the quality of service (QoS). However, QoS of real-time applications depends on the link quality, which necessitate the channel-aware connection admission control (CAC) and scheduling schemes. In this paper Modulation aware CAC scheme and base station (BS) uplink scheduling algorithm are proposed to improve the system capacity and QoS performance respectively. The proposed CAC scheme aims to increase the admission of higher priority real time services by degrading the bandwidth of admitted lower priority connections on the basis of their channel status without deteriorating their QoS performance much. The performances of proposed algorithms are evaluated through simulation by considering the metrics like throughput, delay and number of connections admitted.
A Bandwidth Efficient Scheduling Framework for Non Real Time Applications in ...ijdpsjournal
The key concern on the bandwidth allocation and scheduling for non real time traffic are the fulfillment of its minimum throughput requirement and improvement of bandwidth utilization with acceptable delay. This paper proposes a simple and efficient scheduling framework for allocating bandwidth to non real time
polling service (nrtPS) users in IEEE 802.16 networks. In this framework, jointly selective repeat ARQ at the MAC layer and adaptive modulation and coding techniques at the physical are considered. Numerical simulations demonstrate that the proposed scheduling approach provides a graceful compromise between bandwidth utilization and packet delivery delay while maintaining the minimum throughput requirements of nrtPS applications. Thus proves the efficiency of the proposed framework. The simulation is done for unicast scenario.
Long-Term Evolution (LTE), an emerging and promising fourth generation mobile technology, is expected
to offer ubiquitous broadband access to the mobile subscribers. In this paper, the performance of Frame
Level Scheduler (FLS), Exponential (EXP) rule, Logarithmic (LOG) rule and Maximum-Largest Weighted
Delay First (M-LWDF) packet scheduling algorithms has been studied in the downlink 3GPP LTE cellular
network. To this aim, a single cell with interference scenario has been considered. The performance
evaluation is made by varying the number of UEs ranging from 10 to 50 (Case 1) and user speed in the
range of [3, 120] km/h (Case 2). Results show that while the number of UEs and user speed increases, the
performance of the considered scheduling schemes degrades and in both case FLS outperforms other three
schemes in terms of several performance indexes such as average throughput, packet loss ratio (PLR),
packet delay and fairness index.
DYNAMIC CONGESTION CONTROL IN WDM OPTICAL NETWORKcscpconf
This paper is based on Wavelength Division Multiplexing (WDM) optical networking. In this optical networking, prior to data transfer, lightpath establishment between source and
destination nodes is usually carried out through a wavelength reservation protocol. This wavelength is reserved corresponding to a route between the source and destination and the
route is chosen following any standard routing protocol based on shortest path. The backward reservation protocol is implemented initially. A fixed connected and weighted network is
considered. The inputs of this implementation are the fixed network itself and its corresponding shortest path matrix. After this initial level of implementation, the average node usage over a time period is calculated and various thresholds for node usage are considered. Above threshold value, request arriving at that path selects its next shortest path. This concept is
implemented on various wavelengths. The output represents the performance issues of dynamic congestion control.
Call Admission Control Scheme With Multimedia Scheduling Service in WiMAX Net...Waqas Tariq
WiMAX network introduces a multimedia data scheduling service with different quality of service (QoS) requirements. Transmission opportunities are scheduled by the service according to the types of traffic data for the different connections or users. In the paper, we first propose a uniform definition of QoS level for the multimedia data types in the service. The QoS level of a connection are determined by the type of data of the connection and its allocated resources. Based on these QoS levels, we propose a call admission control (CAC) scheme for the entry admission of a new connection without degrading the network performance and the QoS of ongoing connections. The key idea of this scheme is to regulate the arriving traffic of the network such that the network can work at an optimal point, given under a heavy load traffic. Taking advantage of the simulation experiments, we confirm the fact that the proposed scheme can achieve better trade-off between the overall performance of network system and the QoS level of individual connection.
Modulation aware connection admission control and uplink scheduling algorithm...ijwmn
Mobile WiMAX standard defines air interface for mobile broadband wireless access (BWA) systems and aimed to provide high data rate with seamless mobility while maintaining the quality of service (QoS). However, QoS of real-time applications depends on the link quality, which necessitate the channel-aware connection admission control (CAC) and scheduling schemes. In this paper Modulation aware CAC scheme and base station (BS) uplink scheduling algorithm are proposed to improve the system capacity and QoS performance respectively. The proposed CAC scheme aims to increase the admission of higher priority real time services by degrading the bandwidth of admitted lower priority connections on the basis of their channel status without deteriorating their QoS performance much. The performances of proposed algorithms are evaluated through simulation by considering the metrics like throughput, delay and number of connections admitted.
A Bandwidth Efficient Scheduling Framework for Non Real Time Applications in ...ijdpsjournal
The key concern on the bandwidth allocation and scheduling for non real time traffic are the fulfillment of its minimum throughput requirement and improvement of bandwidth utilization with acceptable delay. This paper proposes a simple and efficient scheduling framework for allocating bandwidth to non real time
polling service (nrtPS) users in IEEE 802.16 networks. In this framework, jointly selective repeat ARQ at the MAC layer and adaptive modulation and coding techniques at the physical are considered. Numerical simulations demonstrate that the proposed scheduling approach provides a graceful compromise between bandwidth utilization and packet delivery delay while maintaining the minimum throughput requirements of nrtPS applications. Thus proves the efficiency of the proposed framework. The simulation is done for unicast scenario.
Long-Term Evolution (LTE), an emerging and promising fourth generation mobile technology, is expected
to offer ubiquitous broadband access to the mobile subscribers. In this paper, the performance of Frame
Level Scheduler (FLS), Exponential (EXP) rule, Logarithmic (LOG) rule and Maximum-Largest Weighted
Delay First (M-LWDF) packet scheduling algorithms has been studied in the downlink 3GPP LTE cellular
network. To this aim, a single cell with interference scenario has been considered. The performance
evaluation is made by varying the number of UEs ranging from 10 to 50 (Case 1) and user speed in the
range of [3, 120] km/h (Case 2). Results show that while the number of UEs and user speed increases, the
performance of the considered scheduling schemes degrades and in both case FLS outperforms other three
schemes in terms of several performance indexes such as average throughput, packet loss ratio (PLR),
packet delay and fairness index.
DYNAMIC CONGESTION CONTROL IN WDM OPTICAL NETWORKcscpconf
This paper is based on Wavelength Division Multiplexing (WDM) optical networking. In this optical networking, prior to data transfer, lightpath establishment between source and
destination nodes is usually carried out through a wavelength reservation protocol. This wavelength is reserved corresponding to a route between the source and destination and the
route is chosen following any standard routing protocol based on shortest path. The backward reservation protocol is implemented initially. A fixed connected and weighted network is
considered. The inputs of this implementation are the fixed network itself and its corresponding shortest path matrix. After this initial level of implementation, the average node usage over a time period is calculated and various thresholds for node usage are considered. Above threshold value, request arriving at that path selects its next shortest path. This concept is
implemented on various wavelengths. The output represents the performance issues of dynamic congestion control.
Qo s oriented distributed routing protocols : anna university 2nd review pptAAKASH S
To find a QoS path between source and destination, Which satisfies
The QoS requirements for each admitted connection and
Optimizes the use of network resources
Quality encompasses the data loss, latency, jitter, efficient use of network resources,..
QoS mechanisms for unfairness: managing queuing behavior, shaping traffic, control admission, routing, …
Usually, a hybrid network has widespread base stations
The data transmission in hybrid networks has two features:
An AP can be a source or a destination to any mobile node
It allows a stream to have anycast transmission along multiple transmission paths to its destination through base stations
The number of transmission hops between a mobile node and an AP is small
It enables a source node to connect to an AP through an intermediate node
In this paper introduce the QoS-Oriented Distributed routing protocol(QOD)
This QOD protocol makes five contributions:
QoS-guaranteed neighbor selection algorithm
Distributed packet scheduling algorithm
Mobility-based segment resizing algorithm
Soft-deadline based forwarding scheduling algorithm
Data redundancy elimination based transmission
Research Inventy : International Journal of Engineering and Scienceinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
A NOVEL HYBRID OPPORTUNISTIC SCALABLE ENERGY EFFICIENT ROUTING DESIGN FOR LOW...IJCNCJournal
Opportunistic Routing (OR) scheme increases the transmission reliability despite the lossy wireless radio links by exploiting the broadcast nature of the wireless medium. However, OR schemes in low power Wireless Sensor Network (WSN) leads to energy drain in constrained sensor nodes due to constant
overhearing, periodic beaconing for Neighbourhood Management (NM) and increase in packet header length to append priority wise sorted Forwarding Candidates Set (FCS) prior to data transmission. The timer-based coordination mechanism incurs the least overhead to coordinate among the FCS that has successfully received the data packet for relaying the data in a multi-hop manner. This timer-based mechanism suffers from duplicate transmissions if the FCS is either not carefully selected or coordinated. The focus of this work is to propose a hybrid opportunistic energy efficient routing design for large scale, low power and lossy WSN. This design avoids periodic 'hello' beacons for NM, limits constant overhearing and increase in packet header length. There are two modes of operation i) opportunistic ii) unicast mode. The sender node adopts opportunistic forwarding for its initial data packet transmission and instead of pre-computing the FCS, it is dynamically computed in a completely distributed manner. The
eligible nodes to be part of FCS will be neighbour nodes at lower corona level than the sender with respect to the sink and remaining energy above the minimum threshold. The nodes part of FCS based on crosslayered multi-metrics and fuzzy decision logic determines its priority level to compute Dynamic Holding
Delay (DHD) for effective timer coordination. The differentiated back off implementation along with DHD enables the higher priority candidate that had received data packet to forward the packet first and facilitates others to cancel its timer upon overhearing. The sender node switches to unicast mode of
forwarding for successive transmissions by choosing the forwarding node with maximum trust value as it
denotes the stability of the temporally varying link with respect to the forwarder. The sender node will revert to opportunistic mode to increase transmission reliability in case of link-level transmission error or no trustworthy forwarders. Simulation results in NS2 show significant increase in Packet Delivery Ratio (PDR),decrease in both average energy consumption per node and Normalized Energy Consumption (NEC) per packet in comparison with existing protocols.
To find a QoS path between source and destination, Which satisfies
The QoS requirements for each admitted connection and
Optimizes the use of network resources
Quality encompasses the data loss, latency, jitter, efficient use of network resources,..
QoS mechanisms for unfairness: managing queuing behavior, shaping traffic, control admission, routing, …
Usually, a hybrid network has widespread base stations
The data transmission in hybrid networks has two features:
An AP can be a source or a destination to any mobile node
It allows a stream to have anycast transmission along multiple transmission paths to its destination through base stations
The number of transmission hops between a mobile node and an AP is small
It enables a source node to connect to an AP through an intermediate node
Impact of Variable Transmission Range and Scalability With Respect To Mobilit...Jitender Grover
A variety of protocols are used in ad hoc network but the most popular protocol one is Zone Routing Protocol (ZRP). ZRP is a hybrid routing protocol. Transmission power affects the design and performance of all the protocols in Mobile Ad hoc Networks (MANETs). Mobility of nodes and selection of Zone Size in ZRP are also the major issues. In this paper, the impact of Transmission Ranges and Scalability by varying Mobility rate along with Zone Radius on QoS based performance metrics has been analyzed. The environment has been simulated using NS2.33 Simulator. The objective of our work is to analyze that at what speed and by taking how much zone radius ZRP will be able to perform efficiently and effectively for Mobile Ad hoc Networks.
Improving data transmission in the vanet using multi criteria decision making...ijfcstjournal
In vehicular ad
-
hoc networks the packets are sent using multi
-
hop methods and the receiving limit of a
message is gradually extended, but the exponential increment of the number of nodes re
-
broadcasting a
message results in broadcast storm problem in data
broadcasting in this case. Some characteristics like
high speed of nodes, rapid topological changes and repetitive discontinuities have made it difficult
to
design an efficient broadcasting protocol for these networks.
We have offered a novel fuzzy method
based on multi
-
criteria decision
-
making (MCDM) for prioritizing the
vehicles in selection of the most proper neighbor to broadcast data in this paper. With using this f
uzzy
method, the most proper vehicles participate in data broadcasting. The results of
simulation using NS show
that because of selecting the neighboring vehicles with high priority in data broadcasting, the spee
d of
sending the packs is increased and the network load is considerably decreased. This method also
considerably decreases broadca
sting traffic.
Congestion Prediction and Adaptive Rate Adjustment Technique for Wireless Sen...IJORCS
In general, nodes in Wireless Sensor Networks (WSNs) are equipped with limited battery and computation capabilities but the occurrence of congestion consumes more energy and computation power by retransmitting the data packets. Thus, congestion should be regulated to improve network performance. In this paper, we propose a congestion prediction and adaptive rate adjustment technique for Wireless Sensor Networks. This technique predicts congestion level using fuzzy logic system. Node degree, data arrival rate and queue length are taken as inputs to the fuzzy system and congestion level is obtained as an outcome. When the congestion level is amidst moderate and maximum ranges, adaptive rate adjustment technique is triggered. Our technique prevents congestion by controlling data sending rate and also avoids unsolicited packet losses. By simulation, we prove the proficiency our technique. It increases system throughput and network performance significantly.
RESOURCE ALLOCATION ALGORITHMS FOR QOS OPTIMIZATION IN MOBILE WIMAX NETWORKSijwmn
WiMAX is based on the standard IEEE 802.16e-2009 for wireless access in Metropolitan Area Networks. It
is one of the solutions for 4G IP based wireless technology. WiMAX utilizes Orthogonal Frequency
Division Multiple Access which also supports Multicast and Broadcast Service with appropriate
Modulation and Coding Scheme. Presently, Scheduling and Resource allocation algorithm in Opportunistic
Layered Multicasting provides multicasting of layered video over mobile WiMAX to ensure better QoS.
Initially, the knowledge based allocation of subcarriers is used for scheduling. In addition, to reduce the
burst overhead, delay and jitter, SWIM (Swapping Min-Max) algorithm is utilized. Another promising
technology that can greatly improve the system performance by exploring the broadcasting nature of
wireless channels and the cooperation among multiple users is the Cooperative Multicast Scheduling
(CMS) technique. The simulation results show, Swapping Min-Max performs better with lesser number of
bursts, Zero jitter and with optimal throughput. The results with Cooperative Multicast Scheduling show
the enhanced throughput for each member in the Multicasting Scenario.
Q-LEARNING BASED ROUTING PROTOCOL TO ENHANCE NETWORK LIFETIME IN WSNSIJCNCJournal
In resource constraint Wireless Sensor Networks (WSNs), enhancement of network lifetime has been one of the significantly challenging issues for the researchers. Researchers have been exploiting machine learning techniques, in particular reinforcement learning, to achieve efficient solutions in the domain of WSN. The objective of this paper is to apply Q-learning, a reinforcement learning technique, to enhance the lifetime of the network, by developing distributed routing protocols. Q-learning is an attractive choice for routing due to its low computational requirements and additional memory demands. To facilitate an agent running at each node to take an optimal action, the approach considers node’s residual energy, hop length to sink and transmission power. The parameters, residual energy and hop length, are used to calculate the Q-value, which in turn is used to decide the optimal next-hop for routing. The proposed protocols’ performance is evaluated through NS3 simulations, and compared with AODV protocol in terms of network lifetime, throughput and end-to-end delay.
A secure qos distributed routing protocol for hybrid wireless networksAAKASH S
The succeeding wireless network is Hybrid Wireless Networks. It can provide Quality of Service
(QoS) requirements in real time transmission for wireless application. But it stream including critical mission
application like military use or emergency recovery. Hybrid wireless networks is unified mobile ad-hoc network
(MANET) and wireless infrastructure networks. It inherits invalid reservation and race condition problem in
Mobile ad-hoc network (MANET). Whereas open medium and wide distribution of node make vulnerable to
malicious attackers in Hybrid wireless networks. How to secure the Quality of Service (QoS) routing in Hybrid
wireless networks. In this paper, we propose a Secure QoS-Oriented Distributed routing protocol (SQOD) to
upgrade the secure Quality of Service (QoS) routing in Hybrid wireless networks. SQOD contain two
contrivances: 1.QoS-Oriented Distributed Routing Protocol (QOD)-to reduce transmission delay, transmission
time. And also increase wireless network transmission throughput. 2. Enhanced Adaptive ACKnowledgment
(EAACK)-implement a new intrusion-detection system for Hybrid wireless networks. It protect Hybrid wireless
networks from attacks that have higher malicious behavior detection rate. Analytical and simulation result
based on the real human mobility mode. SQOD can provide high secure performance in terms of Intrusion detection,overhead, transmission delay.
Macro with pico cells (hetnets) system behaviour using well known scheduling ...ijwmn
This paper demonstrates the concept of using Heterogeneous networks (HetNets) to improve Long Term Evolution (LTE) system by introducing the LTE Advance (LTE-A). The type of HetNets that has been chosen for this study is Macro with Pico cells. Comparing the system performance with and without Pico cells has clearly illustrated using three well-known scheduling algorithms (Proportional Fair PF, Maximum Largest Weighted Delay First MLWDF and Exponential/Proportional Fair EXP/PF). The system is judged based on throughput, Packet Loss Ratio PLR, delay and fairness.. A simulation platform called LTE-Sim has been used to collect the data and produce the paper’s outcomes and graphs. The results prove that adding Pico cells enhances the overall system performance. From the simulation outcomes, the overall system performance is as follows: throughput is duplicated or tripled based on the number of users, the PLR is almost quartered, the delay is nearly reduced ten times (PF case) and changed to be a half (MLWDF/EXP cases), and the fairness stays closer to value of 1. It is considered an efficient and cost effective way to increase the throughput, coverage and reduce the latency.
Hybrid networks is integrate MANETs and infrastructure wireless networks
It have proven to be a better network structure for the next generation networks
It can act Base station and Ad hoc according to the environment conditions
The widespread use of mobile devices the increasing demand for mobile multimedia streaming services
The future of real time need of high Quality of Service (QoS) support in wireless and mobile networking environments
The QoS support reduces end to end transmission delay and enhances throughput to guarantee the seamless communication between mobile devices and wireless infrastructures
Specifically, infrastructure networks improve the scalability of MANETs, while MANETs automatically establish self-organizing networks, extending the coverage of the infrastructure networks
HANDOVER NECESSITY ESTIMATION FOR 4G HETEROGENEOUS NETWORKSijistjournal
One of the most challenges of 4G network is to have a unified network of heterogeneous wireless networks. To achieve seamless mobility in such a diverse environment, vertical hand off is still a challenging problem. In many situations handover failures and unnecessary handoffs are triggered causing degradation of services, reduction in throughput and increase the blocking probability and packet loss. In this paper a new vertical handoff decision algorithm handover necessity estimation (HNE), is proposed to minimize the number of handover failure and unnecessary handover in heterogeneous wireless networks. we have proposed a multi criteria vertical handoff decision algorithm based on two parts: traveling time estimation and time threshold calculation. Our proposed methods are compared against two other methods: (a) the fixed RSS threshold based method, in which handovers between the cellular network and the WLAN are initiated when the RSS from the WLAN reaches a fixed threshold, and (b) the hysteresis based method, in which a hysteresis is introduced to prevent the ping-pong effect. Simulation results show that, this method reduced the number of handover failures and unnecessary handovers up to 80% and 70%, respectively.
Quadrant Based DIR in CWin Adaptation Mechanism for Multihop Wireless NetworkIJCI JOURNAL
In Multihop Wireless Networks, traffic forwarding capability of each node varies according to its level of contention. Each node can yield its channel access opportunity to its neighbouring nodes, so that all the nodes can evenly share the channel and have similar forwarding capability. In this manner the wireless channel is utilized effectively, which is achieved using Contention Window Adaptation Mechanism (CWAM). This mechanism achieves a higher end-to-end throughout but consumes the network power to a higher level. So, a newly proposed algorithm Quadrant- Based Directional Routing Protocol (Q-DIR) is implemented as a cross-layer with CWAM, to reduce the total network power consumption through limited flooding and also reduce the routing overheads, which eventually increases overall network throughput. This algorithm limits the broadcast region to a quadrant where the source node and the destination nodes are located. Implementation of the algorithm is done in Linux based NS-2 simulator
In this project, we proposed a framework to support heterogenous traffic with different QoS demand in
WiMAX. This framework dynamically changes the bandwidth allocation (BA) for ongoing and new arrival
connections based on network condition and service demand. The objective is to efficiently use the
available bandwidth and provide QoS support in a fair manner. Dynamic allocation of spectrum prior to
transmission can mitigate the starvation problem of Non Real time application. The WFQ based dynamic
bandwidth allocation framework uses architecture that has packet scheduler scheme (PS), call admission
policy and a dynamic bandwidth allocation mechanism. By the simulation result we have showed that this
architecture could provide QoS support by being fair to all classes of services.
Qo s oriented distributed routing protocols : anna university 2nd review pptAAKASH S
To find a QoS path between source and destination, Which satisfies
The QoS requirements for each admitted connection and
Optimizes the use of network resources
Quality encompasses the data loss, latency, jitter, efficient use of network resources,..
QoS mechanisms for unfairness: managing queuing behavior, shaping traffic, control admission, routing, …
Usually, a hybrid network has widespread base stations
The data transmission in hybrid networks has two features:
An AP can be a source or a destination to any mobile node
It allows a stream to have anycast transmission along multiple transmission paths to its destination through base stations
The number of transmission hops between a mobile node and an AP is small
It enables a source node to connect to an AP through an intermediate node
In this paper introduce the QoS-Oriented Distributed routing protocol(QOD)
This QOD protocol makes five contributions:
QoS-guaranteed neighbor selection algorithm
Distributed packet scheduling algorithm
Mobility-based segment resizing algorithm
Soft-deadline based forwarding scheduling algorithm
Data redundancy elimination based transmission
Research Inventy : International Journal of Engineering and Scienceinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
A NOVEL HYBRID OPPORTUNISTIC SCALABLE ENERGY EFFICIENT ROUTING DESIGN FOR LOW...IJCNCJournal
Opportunistic Routing (OR) scheme increases the transmission reliability despite the lossy wireless radio links by exploiting the broadcast nature of the wireless medium. However, OR schemes in low power Wireless Sensor Network (WSN) leads to energy drain in constrained sensor nodes due to constant
overhearing, periodic beaconing for Neighbourhood Management (NM) and increase in packet header length to append priority wise sorted Forwarding Candidates Set (FCS) prior to data transmission. The timer-based coordination mechanism incurs the least overhead to coordinate among the FCS that has successfully received the data packet for relaying the data in a multi-hop manner. This timer-based mechanism suffers from duplicate transmissions if the FCS is either not carefully selected or coordinated. The focus of this work is to propose a hybrid opportunistic energy efficient routing design for large scale, low power and lossy WSN. This design avoids periodic 'hello' beacons for NM, limits constant overhearing and increase in packet header length. There are two modes of operation i) opportunistic ii) unicast mode. The sender node adopts opportunistic forwarding for its initial data packet transmission and instead of pre-computing the FCS, it is dynamically computed in a completely distributed manner. The
eligible nodes to be part of FCS will be neighbour nodes at lower corona level than the sender with respect to the sink and remaining energy above the minimum threshold. The nodes part of FCS based on crosslayered multi-metrics and fuzzy decision logic determines its priority level to compute Dynamic Holding
Delay (DHD) for effective timer coordination. The differentiated back off implementation along with DHD enables the higher priority candidate that had received data packet to forward the packet first and facilitates others to cancel its timer upon overhearing. The sender node switches to unicast mode of
forwarding for successive transmissions by choosing the forwarding node with maximum trust value as it
denotes the stability of the temporally varying link with respect to the forwarder. The sender node will revert to opportunistic mode to increase transmission reliability in case of link-level transmission error or no trustworthy forwarders. Simulation results in NS2 show significant increase in Packet Delivery Ratio (PDR),decrease in both average energy consumption per node and Normalized Energy Consumption (NEC) per packet in comparison with existing protocols.
To find a QoS path between source and destination, Which satisfies
The QoS requirements for each admitted connection and
Optimizes the use of network resources
Quality encompasses the data loss, latency, jitter, efficient use of network resources,..
QoS mechanisms for unfairness: managing queuing behavior, shaping traffic, control admission, routing, …
Usually, a hybrid network has widespread base stations
The data transmission in hybrid networks has two features:
An AP can be a source or a destination to any mobile node
It allows a stream to have anycast transmission along multiple transmission paths to its destination through base stations
The number of transmission hops between a mobile node and an AP is small
It enables a source node to connect to an AP through an intermediate node
Impact of Variable Transmission Range and Scalability With Respect To Mobilit...Jitender Grover
A variety of protocols are used in ad hoc network but the most popular protocol one is Zone Routing Protocol (ZRP). ZRP is a hybrid routing protocol. Transmission power affects the design and performance of all the protocols in Mobile Ad hoc Networks (MANETs). Mobility of nodes and selection of Zone Size in ZRP are also the major issues. In this paper, the impact of Transmission Ranges and Scalability by varying Mobility rate along with Zone Radius on QoS based performance metrics has been analyzed. The environment has been simulated using NS2.33 Simulator. The objective of our work is to analyze that at what speed and by taking how much zone radius ZRP will be able to perform efficiently and effectively for Mobile Ad hoc Networks.
Improving data transmission in the vanet using multi criteria decision making...ijfcstjournal
In vehicular ad
-
hoc networks the packets are sent using multi
-
hop methods and the receiving limit of a
message is gradually extended, but the exponential increment of the number of nodes re
-
broadcasting a
message results in broadcast storm problem in data
broadcasting in this case. Some characteristics like
high speed of nodes, rapid topological changes and repetitive discontinuities have made it difficult
to
design an efficient broadcasting protocol for these networks.
We have offered a novel fuzzy method
based on multi
-
criteria decision
-
making (MCDM) for prioritizing the
vehicles in selection of the most proper neighbor to broadcast data in this paper. With using this f
uzzy
method, the most proper vehicles participate in data broadcasting. The results of
simulation using NS show
that because of selecting the neighboring vehicles with high priority in data broadcasting, the spee
d of
sending the packs is increased and the network load is considerably decreased. This method also
considerably decreases broadca
sting traffic.
Congestion Prediction and Adaptive Rate Adjustment Technique for Wireless Sen...IJORCS
In general, nodes in Wireless Sensor Networks (WSNs) are equipped with limited battery and computation capabilities but the occurrence of congestion consumes more energy and computation power by retransmitting the data packets. Thus, congestion should be regulated to improve network performance. In this paper, we propose a congestion prediction and adaptive rate adjustment technique for Wireless Sensor Networks. This technique predicts congestion level using fuzzy logic system. Node degree, data arrival rate and queue length are taken as inputs to the fuzzy system and congestion level is obtained as an outcome. When the congestion level is amidst moderate and maximum ranges, adaptive rate adjustment technique is triggered. Our technique prevents congestion by controlling data sending rate and also avoids unsolicited packet losses. By simulation, we prove the proficiency our technique. It increases system throughput and network performance significantly.
RESOURCE ALLOCATION ALGORITHMS FOR QOS OPTIMIZATION IN MOBILE WIMAX NETWORKSijwmn
WiMAX is based on the standard IEEE 802.16e-2009 for wireless access in Metropolitan Area Networks. It
is one of the solutions for 4G IP based wireless technology. WiMAX utilizes Orthogonal Frequency
Division Multiple Access which also supports Multicast and Broadcast Service with appropriate
Modulation and Coding Scheme. Presently, Scheduling and Resource allocation algorithm in Opportunistic
Layered Multicasting provides multicasting of layered video over mobile WiMAX to ensure better QoS.
Initially, the knowledge based allocation of subcarriers is used for scheduling. In addition, to reduce the
burst overhead, delay and jitter, SWIM (Swapping Min-Max) algorithm is utilized. Another promising
technology that can greatly improve the system performance by exploring the broadcasting nature of
wireless channels and the cooperation among multiple users is the Cooperative Multicast Scheduling
(CMS) technique. The simulation results show, Swapping Min-Max performs better with lesser number of
bursts, Zero jitter and with optimal throughput. The results with Cooperative Multicast Scheduling show
the enhanced throughput for each member in the Multicasting Scenario.
Q-LEARNING BASED ROUTING PROTOCOL TO ENHANCE NETWORK LIFETIME IN WSNSIJCNCJournal
In resource constraint Wireless Sensor Networks (WSNs), enhancement of network lifetime has been one of the significantly challenging issues for the researchers. Researchers have been exploiting machine learning techniques, in particular reinforcement learning, to achieve efficient solutions in the domain of WSN. The objective of this paper is to apply Q-learning, a reinforcement learning technique, to enhance the lifetime of the network, by developing distributed routing protocols. Q-learning is an attractive choice for routing due to its low computational requirements and additional memory demands. To facilitate an agent running at each node to take an optimal action, the approach considers node’s residual energy, hop length to sink and transmission power. The parameters, residual energy and hop length, are used to calculate the Q-value, which in turn is used to decide the optimal next-hop for routing. The proposed protocols’ performance is evaluated through NS3 simulations, and compared with AODV protocol in terms of network lifetime, throughput and end-to-end delay.
A secure qos distributed routing protocol for hybrid wireless networksAAKASH S
The succeeding wireless network is Hybrid Wireless Networks. It can provide Quality of Service
(QoS) requirements in real time transmission for wireless application. But it stream including critical mission
application like military use or emergency recovery. Hybrid wireless networks is unified mobile ad-hoc network
(MANET) and wireless infrastructure networks. It inherits invalid reservation and race condition problem in
Mobile ad-hoc network (MANET). Whereas open medium and wide distribution of node make vulnerable to
malicious attackers in Hybrid wireless networks. How to secure the Quality of Service (QoS) routing in Hybrid
wireless networks. In this paper, we propose a Secure QoS-Oriented Distributed routing protocol (SQOD) to
upgrade the secure Quality of Service (QoS) routing in Hybrid wireless networks. SQOD contain two
contrivances: 1.QoS-Oriented Distributed Routing Protocol (QOD)-to reduce transmission delay, transmission
time. And also increase wireless network transmission throughput. 2. Enhanced Adaptive ACKnowledgment
(EAACK)-implement a new intrusion-detection system for Hybrid wireless networks. It protect Hybrid wireless
networks from attacks that have higher malicious behavior detection rate. Analytical and simulation result
based on the real human mobility mode. SQOD can provide high secure performance in terms of Intrusion detection,overhead, transmission delay.
Macro with pico cells (hetnets) system behaviour using well known scheduling ...ijwmn
This paper demonstrates the concept of using Heterogeneous networks (HetNets) to improve Long Term Evolution (LTE) system by introducing the LTE Advance (LTE-A). The type of HetNets that has been chosen for this study is Macro with Pico cells. Comparing the system performance with and without Pico cells has clearly illustrated using three well-known scheduling algorithms (Proportional Fair PF, Maximum Largest Weighted Delay First MLWDF and Exponential/Proportional Fair EXP/PF). The system is judged based on throughput, Packet Loss Ratio PLR, delay and fairness.. A simulation platform called LTE-Sim has been used to collect the data and produce the paper’s outcomes and graphs. The results prove that adding Pico cells enhances the overall system performance. From the simulation outcomes, the overall system performance is as follows: throughput is duplicated or tripled based on the number of users, the PLR is almost quartered, the delay is nearly reduced ten times (PF case) and changed to be a half (MLWDF/EXP cases), and the fairness stays closer to value of 1. It is considered an efficient and cost effective way to increase the throughput, coverage and reduce the latency.
Hybrid networks is integrate MANETs and infrastructure wireless networks
It have proven to be a better network structure for the next generation networks
It can act Base station and Ad hoc according to the environment conditions
The widespread use of mobile devices the increasing demand for mobile multimedia streaming services
The future of real time need of high Quality of Service (QoS) support in wireless and mobile networking environments
The QoS support reduces end to end transmission delay and enhances throughput to guarantee the seamless communication between mobile devices and wireless infrastructures
Specifically, infrastructure networks improve the scalability of MANETs, while MANETs automatically establish self-organizing networks, extending the coverage of the infrastructure networks
HANDOVER NECESSITY ESTIMATION FOR 4G HETEROGENEOUS NETWORKSijistjournal
One of the most challenges of 4G network is to have a unified network of heterogeneous wireless networks. To achieve seamless mobility in such a diverse environment, vertical hand off is still a challenging problem. In many situations handover failures and unnecessary handoffs are triggered causing degradation of services, reduction in throughput and increase the blocking probability and packet loss. In this paper a new vertical handoff decision algorithm handover necessity estimation (HNE), is proposed to minimize the number of handover failure and unnecessary handover in heterogeneous wireless networks. we have proposed a multi criteria vertical handoff decision algorithm based on two parts: traveling time estimation and time threshold calculation. Our proposed methods are compared against two other methods: (a) the fixed RSS threshold based method, in which handovers between the cellular network and the WLAN are initiated when the RSS from the WLAN reaches a fixed threshold, and (b) the hysteresis based method, in which a hysteresis is introduced to prevent the ping-pong effect. Simulation results show that, this method reduced the number of handover failures and unnecessary handovers up to 80% and 70%, respectively.
Quadrant Based DIR in CWin Adaptation Mechanism for Multihop Wireless NetworkIJCI JOURNAL
In Multihop Wireless Networks, traffic forwarding capability of each node varies according to its level of contention. Each node can yield its channel access opportunity to its neighbouring nodes, so that all the nodes can evenly share the channel and have similar forwarding capability. In this manner the wireless channel is utilized effectively, which is achieved using Contention Window Adaptation Mechanism (CWAM). This mechanism achieves a higher end-to-end throughout but consumes the network power to a higher level. So, a newly proposed algorithm Quadrant- Based Directional Routing Protocol (Q-DIR) is implemented as a cross-layer with CWAM, to reduce the total network power consumption through limited flooding and also reduce the routing overheads, which eventually increases overall network throughput. This algorithm limits the broadcast region to a quadrant where the source node and the destination nodes are located. Implementation of the algorithm is done in Linux based NS-2 simulator
In this project, we proposed a framework to support heterogenous traffic with different QoS demand in
WiMAX. This framework dynamically changes the bandwidth allocation (BA) for ongoing and new arrival
connections based on network condition and service demand. The objective is to efficiently use the
available bandwidth and provide QoS support in a fair manner. Dynamic allocation of spectrum prior to
transmission can mitigate the starvation problem of Non Real time application. The WFQ based dynamic
bandwidth allocation framework uses architecture that has packet scheduler scheme (PS), call admission
policy and a dynamic bandwidth allocation mechanism. By the simulation result we have showed that this
architecture could provide QoS support by being fair to all classes of services.
Two-level scheduling scheme for integrated 4G-WLAN network IJECEIAES
In this paper, a novel scheduling scheme for the Fourth Generation (4G)-Wireless Local Area Network (WLAN) network is proposed to ensure that end to end traffic transaction is provisioned seamlessly. The scheduling scheme is divided into two stages; in stage one, traffic is separated into Actual Time Traffic (ATT) and Non-Actual-Time Traffic (NATT), while in stage two, complex queuing strategy is performed. In stage one, Class-Based Queuing (CBQ) and Deficit Round Robin(DRR) are used for NATT and ATT applications, respectively to separate and forward traffic themselves according to source requirements. Whereas in the stage, two Control Priority Queuing (CPQ) is used to assign each class the appropriate priority level. Evaluation of the performance of the integrated network was done according to several metrics such as end-to-end delay, jitter, packet loss, and network’s throughput. Results demonstrate major improvements for AT services with minor degradation on NAT applications after implementing the new scheduling scheme.
SELFLESS DISTRIBUTED CREDIT BASED SCHEDULING FOR IMPROVED QOS IN IEEE 802.16 ...ijwmn
Packet and flow scheduling algorithms for WiMAX has been a topic of interest for a long time since the very inception of WiMAX networks. WiMAX offers advantages particularly in terms of Quality of service it offers over a longer range at the MAC level. In our paper, we propose two credit based scheduling schemes one in which completed flows distributes the left over credits equally to all higher priority flows(FDCBSS) and another in which completed flows give away all the excess credits to the highest priority uncompleted flow(SDCBSS). Both the schemes are compatible with 802.16 MAC protocol and can efficiently serve real time bursty traffic with reduced latency and hence improved QOS for real time flows. We compare the two proposed schemes for their latency, bandwidth utilization and throughput for real time burst flows with the basic Deficit Round Robin scheduling scheme.
Selfless Distributed Credit Based Scheduling for Improved QOS In IEEE 802.16 ...ijwmn
Packet and flow scheduling algorithms for WiMAX has been a topic of interest for a long time since the
very inception of WiMAX networks. WiMAX offers advantages particularly in terms of Quality of service
it offers over a longer range at the MAC level. In our paper, we propose two credit based scheduling
schemes one in which completed flows distributes the left over credits equally to all higher priority
flows(FDCBSS) and another in which completed flows give away all the excess credits to the highest
priority uncompleted flow(SDCBSS). Both the schemes are compatible with 802.16 MAC protocol and
can efficiently serve real time bursty traffic with reduced latency and hence improved QOS for real time
flows. We compare the two proposed schemes for their latency, bandwidth utilization and throughput for
real time burst flows with the basic Deficit Round Robin scheduling scheme.
Selfless Distributed Credit Based Scheduling for Improved QOS In IEEE 802.16 ...ijwmn
Packet and flow scheduling algorithms for WiMAX has been a topic of interest for a long time since the very inception of WiMAX networks. WiMAX offers advantages particularly in terms of Quality of service it offers over a longer range at the MAC level. In our paper, we propose two credit based scheduling schemes one in which completed flows distributes the left over credits equally to all higher priority flows(FDCBSS) and another in which completed flows give away all the excess credits to the highest priority uncompleted flow(SDCBSS). Both the schemes are compatible with 802.16 MAC protocol and can efficiently serve real time bursty traffic with reduced latency and hence improved QOS for real time flows. We compare the two proposed schemes for their latency, bandwidth utilization and throughput for real time burst flows with the basic Deficit Round Robin scheduling scheme.
Modified q aware scheduling algorithm for improved fairness in 802.16 j networksIJCNCJournal
Deployment of Multi-hop Relays in WiMax based Cellu
lar Networks is considered as a cost effective
solution to increase the Coverage area of Base Stat
ion and also to improve the Network Capacity with h
igh
quality short links. Scheduling became a challengin
g task in these Multi-hop Relay Wireless Cellular
Networks of IEEE 802.16j standard. H. Chen, X. Xie
and H. Wu proposed a Q-aware Scheduling
Algorithm in which back-pressure flow control mecha
nism is used to reflect current Q size of the Relay
s
and considered high back-pressure links to include
in Concurrent Transmission Scenarios, to maximize t
he
throughput. This focus on high back-pressure links,
leads to starvation of Mobile Stations having low
back-
pressure links, resulting unfairness in some cases.
To remedy this situation, a Fair Link Inclusion (F
LI)
mechanism is applied in Greedy Algorithm of Q-aware
Scheduling Algorithm. Simulation results show that
Modified Q-aware Scheduling Algorithm with FLI mech
anism has reasonable improvement in fairness and
maintaining steady throughput when compared with ex
isting algorithms.
Implementing a Session Aware Policy Based Mechanism for QoS Control in LTEIJERA Editor
Quality of Service (QoS) provisioning has become significant with the widely growth of multimedia applications and high increase in the number of users in both wireless and wired networks. In this paper, we implemented a session-aware policy based mechanism for QoS provisioning and control in LTE (Long Term Evolution) networks. Policies are a set of rules identifying the QoS parameters for users. Implementation included DiffServ (Differentiated Services) configuration and setting policies inside the PCRF (Policy Charging Rules Function) which is the brain entity in LTE, then mapping from QCI (QoS Class ID) to DiffServ. Moreover, the dialogue between PCEF (Policy Charging Enforcement Function) and PCRF was implemented. Simulations on four different traffic application types: VoIP (voice over IP), video, web, and ftp (file transfer protocol) were performed under the network simulator (ns2). Results showed that applying PCEF over the different traffic applications has a great effect in controlling these applications and specifically UDP (User Datagram Protocol) based applications such as video.
PERFORMANCE EVALUATION OF DIFFERENT SCHEDULING ALGORITHMS IN WIMAXIJCSEA Journal
Worldwide Interoperability for Microwave Access (WiMAX) networks were expected to be the main Broadband Wireless Access (BWA) technology that provided several services such as data, voice, and video services including different classes of Quality of Services (QoS), which in turn were defined by IEEE 802.16 standard. Scheduling in WiMAX became one of the most challenging issues, since it was responsible for distributing available resources of the network among all users; this leaded to the demand of constructing and designing high efficient scheduling algorithms in order to improve the network utilization, to increase the network throughput, and to minimize the end-to-end delay. In this study, we presenedt a simulation study to measure the performance of several scheduling algorithms in WiMAX, which were Strict Priority algorithm, Round-Robin (RR), Weighted Round Robin (WRR), Weighted Fair Queuing (WFQ), Self-Clocked Fair (SCF), and Diff-Serv Algorithm.
Adaptive Bandwidth Management Model for Wireless Mobile Ad-hoc NetworkIJCNCJournal
The quality of service (QoS) component in a mobile ad-hoc network has an active role in the current network scenario. In a dynamic mobile ad hoc network, ensuring optimum QoS with a scarce network resource is a significant challenge. To achieve QoS, it is essential to adopt some effective and efficient mechanisms. We have proposed an adaptive bandwidth manager model (ABMM) which uses a bandwidthsharing concept along with the flexible bandwidth reservation algorithm (FBRA) for an effective, quick and authentic data transfer. During real-time data transfer, to make communication effective, we make use of bandwidth-sharing network design problems and the concept of reserving bandwidth in high-performance networks. In our proposed model we are concentrating on the maximum utilization of resources, and using the scheduling concept to provide the minimum required bandwidth guarantee to QoS flows. Our goal is to reduce the delay in data transfer and enhance the throughput while properly utilizing the system resources. Our simulation result also shows that our model improves the network performance.
ADAPTIVE BANDWIDTH MANAGEMENT MODEL FOR WIRELESS MOBILE AD-HOC NETWORKIJCNCJournal
The quality of service (QoS) component in a mobile ad-hoc network has an active role in the current
network scenario. In a dynamic mobile ad hoc network, ensuring optimum QoS with a scarce network
resource is a significant challenge. To achieve QoS, it is essential to adopt some effective and efficient
mechanisms. We have proposed an adaptive bandwidth manager model (ABMM) which uses a bandwidthsharing concept along with the flexible bandwidth reservation algorithm (FBRA) for an effective, quick and
authentic data transfer. During real-time data transfer, to make communication effective, we make use of
bandwidth-sharing network design problems and the concept of reserving bandwidth in high-performance
networks. In our proposed model we are concentrating on the maximum utilization of resources, and using
the scheduling concept to provide the minimum required bandwidth guarantee to QoS flows. Our goal is to
reduce the delay in data transfer and enhance the throughput while properly utilizing the system resources.
Our simulation result also shows that our model improves the network performance.
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.
Adaptive Source Provision System (ASPS) for
Proficient Freight Complementary in WiMAX
Network
Today in the wireless network field, WiMAX
(Worldwide Interoperability for Microwave access) has
emerged out as one of the promising networking
technologies. In order to compete with the existing wireless
technologies like Wi-Fi and Bluetooth (IEEE 802.15),
WiMAX has to promise cost efficiency and better quality of
service (QoS). The Adaptive source provision system is
proposed to control traffic rate and ensure load balancing in
the WiMAX network. The proposed approach considers
relay station in the network. When there is an arrival of new
users in the network, its data rate is computed and then
compared with the data rate of RS. When the data rate of
new user is less than that of RS, then the data rate of the
corresponding base station is compared. The connections
are switched from congested stations to non-congested
stations to minimize network load. The handover mechanism
is used by BSs for optimally balancing the traffic load within
the network. LB-based handover mechanism guarantee
user’s QoS and evenly distributes the traffic load. The
experimental analysis showed that the proposed method
achieves better traffic management and load balancing
when compared with the existing approaches.
Fuzzy Based Vertical Handoff Decision Controller for Future NetworksIJAEMSJORNAL
Abstract— In Next generation wireless Networks, the received signals (RSS) from different networks do not have a same meaning since each network is composed of its specific characteristics and there is no common pilot signal. Then, RSS comparisons are insufficient for handoff decision and may be inefficient and impractical. A more complex decision criterion that combines a large number of parameters or factors such as monetary cost, bandwidth, and power consumption and user profile is necessary. Though there are a lot works available for vertical handoff decision (VHD) for wireless networks, the selection of best network is still challenging problem. In this paper we propose a Fuzzy based vertical handoff decision controller (FVHDC) Which performs handover decision based on the output of fuzzy based rules.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
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A Fair and Efficient Packet Scheduling Scheme for IEEE 802.16 Broadband Wireless Access Systems
1. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.1, No.3, September 2010
DOI : 10.5121/ijasuc.2010.1308 93
A Fair and Efficient Packet
Scheduling Scheme for IEEE 802.16 Broadband
Wireless Access Systems
Prasun Chowdhury1
, Iti Saha Misra2
Electronics and Telecommunication Engineering
Jadavpur University, Kolkata, India
1
prasun.jucal@gmail.com, 2
iti@etce.jdvu.ac.in
Abstract
This paper proposes a fair and efficient QoS scheduling scheme for IEEE 802.16 BWA systems that
satisfies both throughput and delay guarantee to various real and non-real time applications. The proposed
QoS scheduling scheme is compared with an existing QoS scheduling scheme proposed in literature in
recent past. Simulation results show that the proposed scheduling scheme can provide a tight QoS
guarantee in terms of delay, delay violation rate and throughput for all types of traffic as defined in the
WiMAX standard, thereby maintaining the fairness and helps to eliminate starvation of lower priority
class services. Bandwidth utilization of the system and fairness index of the resources are also
encountered to validate the QoS provided by our proposed scheduling scheme.
Keywords
IEEE 802.16, MAC, QoS, Packet Scheduling, Fair and efficient
1. Introduction
Wireless networks are generally less efficient and unpredictable compared to wired networks,
which make Quality of Service (QoS) provisioning a bigger challenge for wireless
communications. The wireless medium has limited bandwidth, higher packet error rate, and
higher packet overheads that altogether limit the capacity of the network to offer guaranteed
QoS. In response to increasing QoS challenge, the IEEE 802.16 standard, also known as
Worldwide Interoperability for Microwave Access (WiMAX), has emerged as the strongest
contender for Broadband wireless technology with the promises to offer guaranteed QoS to
wireless users. WiMAX is a technology aimed at providing last-mile wireless broadband access
at a cheaper cost. The “last mile” is the final leg of delivering connectivity from the service
provider to the customer [1]. This leg is typically seen as an expensive undertaking because of
the considerable costs of wires and cables. The core of WiMAX technology is specified by the
IEEE 802.16 standard that provides specifications for the Medium Access Control (MAC) and
Physical (PHY) layers. The term WiMAX was created by the WiMAX forum that promotes
conformance and interoperability of the standard.
In WiMAX network, traffic from the Base Station (BS) to the Subscriber Station (SS) is
classified as downlink traffic while that from the SS to the BS is classified as uplink traffic. A
scheduling algorithm implemented at the BS has to deal with both uplink and downlink traffic.
In some cases, separate scheduling algorithms are implemented for the uplink and downlink
traffic. Typically, a Call Admission Control (CAC) procedure is also implemented at the BS that
ensures the load supplied by the SSs can be handled by the network [1-5]. A CAC algorithm
ensures admission of a SS into the network if it can satisfy minimum Quality of Service (QoS)
2. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.1, No.3, September 2010
94
requirements and at the same time QoS of existing SSs will not deteriorate. The performance of
the scheduling algorithm for the uplink traffic strongly depends on the CAC algorithm.
Scheduling is a critical component of Worldwide Interoperability of Microwave Access
(WiMAX) impacting significantly on its performance. Scheduling schemes helps in providing
service guarantees to heterogeneous classes of traffic with different QoS requirements. In
addition to scheduling, bandwidth request and bandwidth allocation mechanisms also play
crucial roles in QoS provisioning for WiMAX. In general, a scheduler for WiMAX needs to be
simple, efficient, fair, scalable, and have low computational complexity. It should also be able to
protect against misbehaving flows and provide decoupling and necessary bounds on throughput
and delay performance.
Packet scheduling [5-14] is the process of resolving contention for shared resources in a
network. The process involves allocating bandwidth among the users and determining their
transmission order. Scheduling algorithms for a particular network need to be selected based on
the type of users in the network and their QoS requirements. QoS requirements vary depending
on the type of application/user. For real-time applications such as video conferencing, voice chat
and audio/video streaming, delay and delay jitter are the most important QoS requirements.
Delay jitter is the inter-packet arrival time at the receiver and is required to be reasonably stable
by the real-time applications. On the other hand, for non-real time applications such as file
transfer protocol (FTP), throughput is the most important QoS requirement. Some applications,
such as web-browsing and email do not have any QoS requirements. In a network, different
types of applications, with diverse QoS requirements can co-exist. A task of a scheduling
algorithm in a multi-class network is to categorize the users into one of the pre-defined classes.
Each user is assigned a priority taking into account its QoS requirements. Subsequently,
bandwidth is allocated according to the priority of the users as well as ensuring that fairness
between the users is maintained. Fairness refers to the equal allocation of network resources
among the various users operating in both good and bad channel states. In this paper, fairness is
quantified using Jain’s Fairness Index [15]. In addition to it, Bandwidth Utilization of the system
is also encountered to estimate whether precious bandwidth will get wasted by SS lying in a bad
channel state.
Packet scheduling algorithms are implemented at both the BS and SSs. A scheduling
algorithm at the SS is required to distribute the bandwidth allocation from the BS among its
connections. A scheduling algorithm at the SS is not needed if the BS grants bandwidth to each
connection of the SS separately i.e. the Grant per Connection (GPC) procedure is followed. If
the Grant per Subscriber Station (GPSS) procedure is followed, the scheduling algorithm at the
SS needs to decide on the allocation of bandwidth among its connections. The scheduling
algorithm implemented at the SS can be different than that at the BS [8].
The focus of our work is on scheduling algorithms for the uplink traffic in WiMAX i.e. traffic
from the SSs to the BS. Uplink packet scheduling is a more challenging task than downlink
packet scheduling as all the necessary information of SSs such as queue size for the uplink
scheduling are not available. An uplink algorithm at the BS has to coordinate its decision with
all the SSs where as a downlink algorithm is only concerned in communicating the decision
locally to the BS.
K. Wongthavarawat et al. propose a hybrid scheduling algorithm in [1] that combines Earliest
Deadline First (EDF), Weighted Fair queuing (WFQ) and First in First out (FIFO) scheduling
algorithms. The overall allocation of bandwidth is done in a strict priority manner i.e. all the
higher priority SSs are allocated bandwidth until they do not have any packets to send. The EDF
scheduling algorithm is used for SSs of the rtPS class, WFQ is used for SSs of the Non-Real
Time Polling Service (nrtPS) class and FIFO for SSs of the Best Effort (BE) class. Besides the
scheduling algorithm, an admission control procedure and a traffic policing mechanism are also
proposed. All these components together constitute the proposed QoS architecture. A drawback
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of this algorithm is that lower priority SSs will essentially starve in the presence of a large
number of higher priority SSs due to the strict priority overall bandwidth allocation.
J. Lin et al. [8] propose architecture called Multi-class Uplink Fair Scheduling Structure
(MUFSS) to satisfy throughput and delay requirements of the multi-class traffic in WiMAX. The
proposed scheduling discipline at the BS is Modified Weighted Round Robin (MWRR),
although details of the modifications to the Weighted Round Robin (WRR) discipline are not
provided by the authors. The model is based on Grant per Subscriber Station (GPSS) bandwidth
grant mode and thus schedulers are implemented at the SSs to distribute the bandwidth granted
among their connections. At the SS, Modified WFQ (MWFQ) is used for Unsolicited Grant
Service (UGS) and Real-Time Polling Service (rtPS) connections, MWRR is used for nrtPS
connections and FIFO is used for BE connections.
K. Vinay et al. [9] propose a hybrid scheme that uses EDF for SSs of the rtPS class and WFQ
for SSs of the nrtPS and BE classes. This algorithm differs from the one in [1] in a couple of
ways. First, the WFQ algorithm is used for SSs of both nrtPS and BE classes. Secondly, the
overall bandwidth allocation is not done in a strict priority manner. Although the details of
overall bandwidth allocation are not specified, it is briefly mentioned that the bandwidth is
allocated among the classes in a fair manner. Since SSs of the BE class do not have any QoS
requirements, using a computationally complex algorithm such as WFQ for them is not needed.
Here author made the comparative study of the scheduling algorithms implemented in GPSS and
GPC and found that GPSS gives better end-to-end delay.
M.Settembre et al. [10] propose a hybrid scheduling algorithm that uses WRR and Round
Robin (RR) algorithms with a strict priority mechanism for overall bandwidth allocation. In the
initial portion of the algorithm, bandwidth is allocated on a strict priority basis to SSs of the rtPS
and nrtPS classes only. After that the WRR algorithm is used to allocate bandwidth among SSs
of rtPS and nrtPS classes until they are satisfied. If any bandwidth remains, it is distributed
among the SSs of the BE class using the RR algorithm. This algorithm starves lower priority SSs
in the presence of a large number of higher priority SSs. The algorithm can also result in low
fairness among SSs as it selects SSs with the most robust burst profiles first.
J. SUN et al. [11] proposed that the scheduler inside the BS may have only limited or even
outdated information about the current state of each uplink connection due to the large Round
Trip Delay (RTD) and possible collision occurred in the uplink channel transmission. So there is
a need of an additional scheduler in each SS to reassign the received transmission opportunities
among different connections. Since the uplink traffic is generated at SS, the distributed scheduler
is able to arrange the transmission based on the up-to-date information and then provide QoS
guarantee for its connections. But here the proposed algorithm is suffered by a problem called as
starvation of lower priority class services.
It is observed that the existing wire line and wireless schedulers do not perform very well
with respect to different traffic classes defined in WiMAX. In addition, each of this traffic
classes has a different scheduling requirement and, consequently, it has become necessary to
design appropriate hybrid scheduling frameworks. So in the proposed method the uplink traffic
is scheduled based on current queue information at SS similarly in the way proposed in [11]. But
a different hybrid algorithm has been implemented at the SS scheduler which helps to eliminate
the starvation of lower priority class services also maintains proper fairness and bandwidth
utilization of the system even at lower traffic intensity. In the proposed method the BS scheduler
can guarantee the minimum bandwidth for each service flow and ensure fairness and QoS in
distributing excess bandwidth among all connections. At the same time, the scheduler in SS can
provide differentiated and flexible QoS support for all of the four scheduling service types. In
this paper EDF algorithm is applied for rtPS class of services and Deficit Fair Priority Queue
(DFPQ) algorithm found in literature [12],[13] is applied for nrtPS and BE class of services. It
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can both reduce the delay of real-time applications and guarantee the throughput of non-real-
time applications such as nrtPS and BE.
The rest of the paper is organized as follows; The QoS related features of IEEE 802.16
standard are discussed in section 2. Then the proposed scheduling algorithms are introduced in
section 3. Section 4 provides simulation and performance analysis. Finally, this paper is ended
up with the conclusions drawn in section 5.
2. QoS Features of IEEE 802.16
The first version, known as 802.16, was completed in October 2001. It specified a Single
Carrier (SC) air interface for fixed point-to-multipoint (PMP) BWA systems operating between
10-66 GHz. The second amendment, 802.16a, was published in January 2003. It extends the
physical environment towards lower frequency bands below 11 GHz. The next approved version
is 802.16d, which is published in June 2004 and also known as FIXED WiMAX (802.16-2004).
It incorporates all the previous versions to provide fixed BWA. In 2005, IEEE undertakes the
standardization of 802.16e, which is expected to support full mobility up to 70-80miles/sec [6].
Four service types are defined in IEEE 802.16d-2004 (Fixed) standard, which includes UGS
(Unsolicited Grant Service), rtPS (Real-time Polling Service), nrtPS (Non Real-time Polling
Service), and BE (Best Effort). The UGS is designed to support real-time service flow that
generates fixed-size data periodically, such as T1/E1, VoIP without silence suppression [1], [6].
The rtPS is designed to support real-time service flow that generates variable size data, such as
video streaming services while the nrtPS deals with FTP in similar manner. The BE perform
tasks related to e-mail and web browsing. The guaranteed delay aspect is also taken care in video
streaming and VoIP.
Since IEEE 802.16 MAC protocol is connection oriented, the application first establishes the
connection with the BS as well as the associated service flow (UGS, rtPS, nrtPS or BE). BS will
assign the connection with a unique connection ID (CID) [1], [6]. All packets from the
application layer in the SS are classified by the connection classifier based on CID and are
forwarded to the appropriate queue. So, the scheduler inside the BS has outdated information
about the current state of each uplink connection due to the large Round Trip Delay (RTD) and
possible collision occurred in the uplink channel transmission [14].
3. Proposed Scheduling Algorithm
In the proposed method, the uplink bandwidth allocation at BS is done based on the per
connection requests from SSs. Because a SS may have multiple connections at the same time,
the bandwidth request messages should report the bandwidth requirement of each connection in
SS. After that the allocated bandwidth per connection is pooled together and granted to each SS.
Then SS re-distribute the received transmission opportunities among its connections according
to their QoS requirement. Therefore an additional scheduler is needed in each SS to reassign the
received transmission opportunities among different connections. Since the uplink traffic is
generated at SS, the distributed scheduler is able to arrange the transmission based on the up-to-
date information and then provide tight QoS guarantee for its connections.
Since the BS scheduler has limited information on the traffic generated at SS, the computing
of bandwidth allocation should just consider the bandwidth request and reservation for each
connection.
Let BWMINi denote the minimum reserved bandwidth for connection i, and BWREQi
represent the bandwidth currently demanded by the connection i. Since the connection will never
get more resources than it has requested, the bandwidth actually allocated (BWALLOCATEi)
during this phase is
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BWALLOCATEi = min {BWMINi, BWREQi} (1)
For rtPS and nrtPS, BWMINi is specified by the QoS parameter termed Minimum Reserved
Traffic Rate. Clearly, to guarantee the contracted bandwidth, the sum of minimum reserved
bandwidth for all the connections should not exceed the available bandwidth B. After each
connection gets its guaranteed bandwidth, if there is still excess uplink bandwidth remained, BS
scheduler should distribute the residual bandwidth in proportion to the pre-assigned connection
weight. The algorithm in this phase can be described as:
BWREMAIN = B - ∑ BWALLOCATEi;
i
While BWREMAIN > 0
{
If (BWALLOCATEi < BWREQi)
{
n
BWADDi = BWREMAIN*Wi / ∑ Wk;
k=1
BWALLOCATEi = BWALLOCATEi + BWADDi;
BWREMAIN = BWREMAIN - BWADDi;
}
}
Where BWREMAIN is the remaining bandwidth, BWADDi is the amount of excess
bandwidth allocated to connection queue i and Wi is the weight of connection queue i. Now the
allocated bandwidth per connection is pooled together and granted to each SS.
SS scheduler will select the packet to be transmitted from the highest priority queue. The
priority of the queue is maintained in the following way UGS > rtPS > nrtPS > BE.
3.1 Scheduling algorithm for UGS queues
UGS generate fixed size data packets on a periodic basis. This service has a critical delay and
delay jitter requirement. So, SS scheduler firstly guarantees the bandwidth for UGS queues.
3.2 Scheduling algorithm for rtPS queues
For rtPS service, each packet entering the rtPS queues should be marked with a delivery
deadline equal to t + tolerated delay, where t is the arrival time and tolerated delay is the
Maximum Latency for such a service flow. The packet with smaller deadline will be transmitted
earlier. This greatly reduces the end-to-end delay of rtPS service.
3.3 Scheduling algorithm for nrtPS and BE queues
For nrtPS and BE services Deficit Fair Priority Queue (DFPQ) algorithm found in literature
[12], [13] is employed. DFPQ is almost similar to Deficit Round Robin (DRR) algorithm. This
algorithm has been applied because of the following reasons.
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i. The algorithm is mostly suited for datagram networks where packet sizes vary.
ii. Since this algorithm requires accurate knowledge of packet size, it is suitable for the
uplink traffic at SS scheduler.
iii. The algorithm is flexible enough as it allows provision of quanta of different sizes
depending on the QoS requirements of the SSs. With this algorithm employed, SS
scheduler can guarantee the minimum bandwidth for every non real time services such
as nrtPS and BE connection and hence maintain an acceptable throughput. Thereby
eliminate starvation of lower priority service classes.
In each service round, the nrtPS queue is served first until its assigned bandwidth finds
deficit, and then BE service flow queue gets a chance to be served. Similar to [12], in DFPQ
algorithm, a Quantum Q is assigned to each queue i. The quantum of a queue i (Q[i]) represent
the maximum number of bits that can be serviced in the first round. The scheduler visits each
nonempty queue and determines the number of bandwidth requests in this queue. If there are
more packets in the queue i after servicing Q[i] bits, the remaining amount of bits is stored in a
queue state variable called Deficit Counter (DC[i]) and the scheduler moves on to serve the next
non-empty queue. In subsequent rounds, the amount of bandwidth usable by this flow is the sum
of DC[i] in the previous round added to Q[i]. The Q[i] is the Maximum Sustained traffic rate
(rmax) of a certain service flow. In case rmax = 0 (BE service flow), rmin is used instead. As a
result of using the quantum variable, connections with larger quantum get more service.
DFPQ algorithm is shown below. Here Ltotal is defined to be the remaining total capacity of
the frame after servicing UGS and rtPS queues and La to be its remaining capacity. p(i,k)
denotes kth
packet of ith
connection, i belongs to nrtPS and BE connections. The algorithm can be
described as follows,
Each service queue i of nrtPS and BE is initialized with
La = Ltotal;
DC[i] = Q[i];
While La > 0
{
While DC[i]>0 and p (i, k) is available
{
DC[i] = DC[i] - p(i,k);
La =La – p(i,k);
k++;
}
DC[i] = DC[i] + Q[i];
i = (i % n) + 1;
}
Go to UGS scheduling for next frame
4. Simulation and Performance Analysis
To evaluate the effectiveness and efficiency of the proposed scheduler, the IEEE 802.16
MAC layer protocol is analyzed using MATLAB under version 7.3. A number of simulations are
conducted in this section. At first, the simulation environment and parameters are described and
simulation results are given along with the discussions.
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4.1. Simulation Environment and Parameters
A TDD-OFDM system is used in our simulation with the MAC layer application parameters
as shown in Table 1 and the network is configured as consists of one BS and multiple SSs as
shown in Fig 1.
Figure1. Proposed model architecture
The frame duration is taken as 10ms with TDD duplex mode and the bandwidth is 4.3 MHz.
The IEEE 802.16 standards have not specified values for the QoS parameters and we have
assumed these values for the performance analysis.
Table1. MAC layer configuration parameters
Service
Max
Sustained
Rate
(kbps)
Min
Reserved
Rate
(kbps)
Delay
(ms)
UGS 256 - -
rtPS 1024 512 20
nrtPS 1024 512 -
BE - 256 -
QoS parameters such as delay, delay violation rate, throughput, bandwidth utilization and
fairness index are considered to validate our proposed scheduling scheme. Here, the delay
violation rate is defined as the amount of packets whose delay is larger than the Maximum
Latency to the total amount of packets that have been received from network interface. Also the
bandwidth utilization is defined as the average ratio of used bandwidth to the total bandwidth
and Fairness is quantified using Jain’s Fairness Index (JFI) [15] as shown below.
∑
∑
=
=
∗
= n
1i
2
i
2
n
1i
i
rn
)r(
JFI (2)
Where, ri is the data rate of application i.
4.2. Simulation Result and Discussions
In the simulation we consider 802.16 network consisting of one BS and four SSs with
different traffic patterns. The first SS is configured with all types of traffic flows nominated as
UGS_1, rtPS_1, nrtPS_1 and BE_1, the second SS has UGS_2, rtPS_2, nrtPS_2 and BE_2, the
third SS has UGS_3, rtPS_3, nrtPS_3 and BE_3, the fourth SS runs UGS_4, rtPS_4, nrtPS_4 and
BE_4. Two scenarios - with and without SS scheduler are simulated to study the effect of SS
scheduler.
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Figure 2.Service delay comparison
Our proposed method is compared with the method given in [11]. Here, “without SS
scheduler” and “BS-(service class)” means that BS scheduler designates bandwidth to individual
connection. On the other hand, “with SS-scheduler1” and “SS1-(service class)” means that SS
scheduler designates bandwidth to individual connection in our proposed method. Again “with
SS-scheduler2” and “SS2-(service class)” means that SS scheduler designates bandwidth to
individual connection proposed in [11]. Here, service class refers to UGS, rtPS, nrtPS and BE.
As UGS generates fixed size data packets on a periodic basis so delay is negligible and
throughput is constant and hence it is not shown in our simulation result. Fig. 2 displays the end-
to-end delay of different services with and without SS scheduler. The curves show that after SS
scheduling, low priority service suffered longer delay. From rtPS, nrtPS to BE, the end-to-end
delay increased with the service priority decreased. The fundamental requirement of QoS
scheduling for IEEE 802.16 systems is achieved.
Figure 3.Service delay comparison of rtPS
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Figure 4.Percentage of packet drop comparison
To further demonstrate this benefit, we simulate the rtPS performance under the same number
of background SS as given in Fig. 3. From Fig.4 we can see that the SS scheduler can effectively
reduce the QoS violation rate of rtPS service flow.
Figure 5.Throughput comparison proposed in [11]
Figure 6.Throughput comparison in our proposed Strategy
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By introducing DFPQ algorithm for nrtPS and BE services on priority order, SS scheduler can
guarantee the throughput of nrtPS service as well as BE service. Though BE services do not
require any QoS but in our proposed algorithm fairness is maintained for all types of service
classes. But this fairness is not maintained in [11] where we got throughput of BE service is zero
as shown in Fig.5. But our simulation result shows that SS scheduler guarantees the throughput
of nrtPS service as well as BE service as shown in Fig.6 where throughput of BE service is
greater than zero throughout simulation time, hence fairness of all the services is maintained and
the problem of starvation of lower priority class services is eliminated.
Figure 7.Bandwidth Utilization of the system
Figure 8.Jain’s Fairness Index
Fig. 7 and 8 show bandwidth utilization of the system and fairness index for BS-Scheduler,
SS1-Scheduler and SS2-Scheduler with different traffic intensity. Our results show that SS1-
Scheduler performs well even at lower traffic intensity. As bandwidth is considered to be a
limited resource in the network, so SS1-Scheduler will automatically improve the revenues of
the service providers.
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5. Conclusion
It has been confirmed in many earlier studies that most of the existing wire line and wireless
homogeneous schedulers do not perform very well with respect to different traffic classes
defined in WiMAX. In addition, each of this traffic classes has a different scheduling
requirement and consequently, it has become necessary to design appropriate hybrid scheduling
frameworks. Therefore, we propose an efficient hybrid packet scheduling scheme for IEEE
802.16 WiMAX to satisfy both delay and throughput guarantees for the admitted connections.
An architecture model was developed to demonstrate the performance of the proposed scheme.
Simulation results show that the proposed scheme is the best choice for QoS scheduling in
WiMAX in terms of delay, throughput, bandwidth utilization and fairness of all connections of
the system compared to schemes proposed in [11]. Simulation results also prove that the BS
scheduler can guarantee the minimum bandwidth for each service flow and ensure fairness and
QoS in distributing excess bandwidth among all connections. At the same time, the scheduler in
SS can provide differentiated and flexible QoS support for all of the four scheduling service
types. It can both reduce the delay of real-time applications and guarantee the throughput of non-
real-time applications also enhancing the bandwidth utilization of the system and fairness index
of the resources even at lower traffic intensity. Thereby eliminate starvation problem of lower
priority class services. Therefore, the proposed QoS scheduling architecture can provide tight
QoS guarantees for all types of traffic classes as defined in the scheduler standard.
Acknowledgement
The authors deeply acknowledge the support from DST, Govt. of India for this work in the form
of FIST 2007 Project on “Broadband Wireless Communications” in the Department of ETCE,
Jadavpur University.
REFERENCES
[1] K. Wongthavarawat, and A. Ganz, “Packet scheduling for QoS support in IEEE 802.16
broadband wireless access systems”, International Journal of Communication Systems, vol. 16,
issue 1, pp. 81-96, February (2003).
[2] Haitang Wang, Wei Li and Dharma P. Agrawal, “Dynamic admission control and QoS for IEEE
802.16 Wireless MAN”, Proc. of Wireless Telecommunications Symposium, April 6-7 2005, pp.
60-66, (WTS 2005).
[3] Dusit Niyato and Ekram Hossain, “Connection Admission Control Algorithms for OFDM
Wireless Networks” , Proc. of IEEE Globecom, pp.2455-2459, (2005).
[4] Kalikivayi Suresh, Iti Saha Misra and Kalpana saha (Roy), “Bandwidth and Delay Guaranteed
Call Admission Control Scheme for QOS Provisioning in IEEE 802.16e Mobile WiMAX”
Proceedings of IEEE GLOBECOM, pp.1245-1250, December (2008).
[5] Chi-Hong Jiang, Tzu-Chieh Tsai, “CAC and Packet Scheduling Using Token bucket for IEEE
802.16 Networks”, Consumer Communications and Networking Conf., 2006. CCNC 2006. 3rd
IEEE Volume 1, pp. 183-187, Issue, 8-10 Jan. (2006).
[6] Jeffery G.Andrews, Arunabha Ghosh, Rias Muhamed, “Fundamentals of WiMAX-Understanding
Broadband Wireless Networking”, Pearson Education, March (2007).
[7] Prasun Chowdhury and Iti Saha Misra, “A Comparative Study of Different Packet Scheduling
Algorithms with Varied Network Service Load in IEEE 802.16 Broadband Wireless Access
Systems” IEEE Proc. Int. Conf. Advanced Computing & Communications, Bangalore, Dec.
(2009).
12. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.1, No.3, September 2010
104
[8] J.Lin and H.Sirisena, “Quality of Service Scheduling in IEEE 802.16 Broadband Wireless
Networks”, Proceedings of First International Conference on Industrial and Information Systems,
pp.396-401, August (2006).
[9] K.Vinay, N.Sreenivasulu, D.Jayaram and D.Das, “Performance evaluation of end-to-end delay by
hybrid scheduling algorithm for QoS in IEEE 802.16 network”, Proceedings of International
Conference on Wireless and Optical Communication Networks, 5 pp., April (2006).
[10] M.Settembre, M.Puleri, S.Garritano, P.Testa, R.Albanese, M.Mancini and V.Lo Curto,
“Performance analysis of an efficient packet-based IEEE 802.16 MAC supporting adaptive
modulation and coding”, Proceedings of International Symposium on Computer Networks,
pp.11-16, June (2006).
[11] J.Sun, Y. Yao, H. Zhu “Quality of Service Scheduling For 802.16 Broadband Wireless Access
System”, Advanced system technology telecom lab (Beijing) china, IEEE, (2006).
[12] M.Shreedhar and G.Varghese, “Efficient Fair Queuing using Deficit Round Robin”, IEEE/ACM
Transactions on Networking, vol.1, no.3, pp.375-385, June (1996).
[13] H.Safa, H.Artail, M. Karam, R. Soudah, S. Khyat “New Scheduling Architecture for IEEE 802.16
Wireless Metropoliton Area Network”, American university of Beirut, Lebanon IEEE (2007).
[14] CuoSong Chu, Deng Wang, Shunliang Mei, "A QoS architecture for the MAC protocol of IEEE
802.16 BWA system," IEEE Communications, pp. 435-439, Jul. (2002).
[15] A. Haider and R. Harris, “A novel proportional fair scheduling algorithm for HSDPA in UMTS
networks”, Proceedings of 2nd
IEEE AusWireless, 43-50, 2007.
BIOGRAPHIES
1. Mr. Prasun Chowdhury (prasun.jucal@gmail .com) has completed his Masters in Electronics and
Telecommunication Engineering from Jadavpur University, Kolkata, India in 2009. Presently he is
working as Senior Research Fellow (SRF) and also pursuing his PhD in the Department of
Electronics and Telecommunication Engineering, Jadavpur University, Kolkata, India. His current
research interests are in the areas of Call Admission Control and Packet Scheduling in IEEE 802.16
BWA Networks.
2. Dr. Iti Saha Misra (itimisra@cal.vsnl.net.in) is presently holding the post of Professor in the
Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata,
India. After the completion of her PhD in Engineering in the field of Microstrip Antennas from
Jadavpur University (1997), she is actively engaged in teaching since 1997. Her current research
interests are in the areas of Mobility Management, Network Architecture and protocols, Integration
Architecture of WLAN and 3G Networks, Call Admission control and packet scheduling in cellular
and WiMAX networks, Location Management for Cellular Wireless Networks. Her other research
activities are related to Design Optimization of Wire Antennas using Numerical Techniques like
GA, PSO and BFA. She has authored more than 100 research papers in refereed Journal and
International Conference and published a Book on Wireless Communications and Networks, by
McGraw Hill, India. She is the recipient of the Career award for Young teachers by All India
Council for Technical Education (AICTE) for the financial year 2003-2004 and obtained the IETE
Gowri memorial award in 2007 for being the best paper in the general topic of “4G networks:
Migration to the Future”. She has developed the OPNET, QualNet and VoIP laboratories in the
Department of Electronics and Telecommunication Engineering of Jadavpur University to carry out
advanced research work in Broadband wireless domain. She is the Senior Member of IEEE, founder
Chair of the Women In Engineering, Affinity Group, IEEE Calcutta Section.