The 3GPP Long Term Evolution Advanced (LTE-A) standard specifies a set of pioneer features such as relay nodes and carrier aggregation. At the same time, the Software Defined Networks (SDN) have become an emerging technology which provides centralized control and programmability to modern networks. In the current communication environment, cloud computing could combine the advantages of both technologies in order to create a novel cloud assisted Software Defined LTEA architecture with relay nodes. Moreover, due to the increased requirements of modern services, the optimal resource allocation is a necessity. In such a context, this paper describes a QoS aware cross carrier scheduler for downlink flows, aiming at the optimization of system resources allocation. The proposed scheduler is evaluated against the PF, MLWDF, EXP/PF, EXP RULE, LOG RULE, FLS and FLSA schedulers in a cloud assisted Software Defined LTE-A topology with relay nodes. Simulation results show that the proposed scheduler improves the real time services performance while at the same time maintains an acceptable performance for best effort flows.
A downlink scheduler supporting real time services in LTE cellular networksUniversity of Piraeus
The wide spread of real-time services in wireless networks demands scheduling mechanisms supporting strict Quality of Service (QoS) requirements. Nevertheless, the specifications of the LTE standard for mobile connectivity defined by the 3rd Generation Partnership Project (3GPP) does not impose any specific scheduler for the proper allocation of resources to services. Therefore, several LTE schedulers have been proposed in the literature meeting the QoS requirements of modern services. In this paper a QoS aware scheduler for the LTE downlink is proposed namely the FLS-Advanced (FLSA) aiming at prioritizing real-time traffic. The proposed scheduler has been built on three distinct levels assigning the available radio resources to services according to their requirements. Based on simulation results, the FLSA outperforms in terms of packet loss ratio, attainable throughput and fairness the performance of existing schedulers including PF, MLWDF, EXP/PF, FLS, EXP RULE and LOG RULE.
Long-Term Advancement Progressed (LTE-ADV) is the advancement of the long-term evolution,
which created via 3GPP. LTE-ADV aims to offer a transmission bandwidth of (100) MHz by using Carrier
Aggregation (CA) to aggregate LTE-ADV carriers. To increase the data capacity of the system and
resource allocation converts a very good tool. LTE-Advanced multiple Component Carriers (CCs) becomes
a difficult optimization problem. In the paper proposes a new scheduling algorithm and compares with a
different scheduling traditional algorithms that are proportional fair and round robin in the CA, in order to
find the best scheduler that provides high-quality throughput and improves fairness. It also evaluates
mapping model types are Mutual Information Effective SINR Mapping (MIESM) and Exponential Effective
SINR Mapping (EESM). The results show that the throughput in the proposed algorithm with MIESM
outperforms from others mapping and scheduling.
Multiple Downlink Fair Packet Scheduling Scheme in Wi-MaxEditor IJCATR
IEEE 802.16 is standardization for a broadband wireless access in network metropolitan area network (MAN). IEEE 802.16
standard (Wi-Max) defines the concrete quality of service (QoS) requirement, a scheduling scheme and efficient packet scheduling
scheme which is necessary to achieve the QoS requirement. In this paper, a novel waiting queue based on downlink bandwidth
allocation architecture from a number of rtps schedule has been proposed to improve the performance of nrtPS services without any
impaction to other services. This paper proposes an efficient QoS scheduling scheme that satisfies both throughput and delay guarantee
to various real and non-real applications corresponding to different scheduling schemes for k=1,2,3,4. Simulation results show that
proposed scheduling scheme can provide a tight QoS guarantee in terms of delay for all types of traffic as defined in WiMax standards.
This process results in maintaining the fairness of allocation and helps to eliminate starvation of lower priority class services. The
authors propose a new efficient and generalized scheduling schemes for IEEE 802.16 broadband wireless access system reflecting the
delay requirements.
3GPP has introduced LTE Femtocells to manipulate the traffic for indoor users and to minimize
the charge on the Macro cells. A key mechanism in the LTE traffic handling is the packet
scheduler which is in charge of allocating resources to active flows in both the frequency and
time dimension. So several scheduling algorithms need to be analyzed for femtocells networks.
In this paper we introduce a performance analysis of three distinct scheduling algorithms of
mixed type of traffic flows in LTE femtocells networks. The particularly study is evaluated in
terms of throughput, packet loss ratio, fairness index and spectral efficiency.
This document summarizes a research paper that proposes using a hybrid of simulated annealing algorithm and fuzzy rule base system (SA-FRBS) for adaptive coding, modulation, and power allocation in orthogonal frequency-division multiplexing (OFDM) systems. The paper first discusses related work on using evolutionary algorithms like genetic algorithms for adaptive resource allocation in OFDM. It then describes the system model and analyzes the performance of different modulation and coding schemes. Next, it formulates the rate optimization problem and describes the design of the FRBS for selecting the optimal modulation-coding pairs. Finally, it compares the performance of the proposed SA-FRBS approach through simulations.
This document discusses adaptive multistreaming over a network using the Stream Control Transmission Protocol (SCTP). It proposes adapting the number of streams based on estimates of available bandwidth and current congestion window size to improve performance under congestion. The performance of this adaptive streams mechanism is evaluated through computer simulation using the OMNeT++ network simulation tool and INET framework. Simulation results are compared between the proposed adaptive streams approach and normal SCTP streaming.
Analytical average throughput and delay estimations for LTESpiros Louvros
This document summarizes an article that appeared in a journal published by Elsevier. The article proposes an analytical model to estimate average throughput and packet transmission delay for uplink cell edge users in LTE networks. The model uses probability analysis and mathematical modeling to estimate transmission delay and throughput, providing cell planners with an analytical tool for evaluating uplink performance under different conditions. The model accounts for factors like scheduling decisions, resource allocation, channel conditions and buffering that impact transmission delay and throughput for cell edge users.
FREQUENCY AND TIME DOMAIN PACKET SCHEDULING BASED ON CHANNEL PREDICTION WITH ...ijwmn
1) The document discusses packet scheduling algorithms for LTE downlink systems that must operate under imperfect channel quality information (CQI) due to errors, delays, and other issues.
2) It proposes a new packet scheduling algorithm that uses a Kalman filter-based channel predictor in the frequency domain to estimate the true CQI from erroneous feedback, combined with a time domain grouping technique using proportional fair and modified largest weighted delay first algorithms.
3) Simulation results showed this approach achieves better performance than existing algorithms in terms of system throughput and packet loss ratio under imperfect CQI conditions.
A downlink scheduler supporting real time services in LTE cellular networksUniversity of Piraeus
The wide spread of real-time services in wireless networks demands scheduling mechanisms supporting strict Quality of Service (QoS) requirements. Nevertheless, the specifications of the LTE standard for mobile connectivity defined by the 3rd Generation Partnership Project (3GPP) does not impose any specific scheduler for the proper allocation of resources to services. Therefore, several LTE schedulers have been proposed in the literature meeting the QoS requirements of modern services. In this paper a QoS aware scheduler for the LTE downlink is proposed namely the FLS-Advanced (FLSA) aiming at prioritizing real-time traffic. The proposed scheduler has been built on three distinct levels assigning the available radio resources to services according to their requirements. Based on simulation results, the FLSA outperforms in terms of packet loss ratio, attainable throughput and fairness the performance of existing schedulers including PF, MLWDF, EXP/PF, FLS, EXP RULE and LOG RULE.
Long-Term Advancement Progressed (LTE-ADV) is the advancement of the long-term evolution,
which created via 3GPP. LTE-ADV aims to offer a transmission bandwidth of (100) MHz by using Carrier
Aggregation (CA) to aggregate LTE-ADV carriers. To increase the data capacity of the system and
resource allocation converts a very good tool. LTE-Advanced multiple Component Carriers (CCs) becomes
a difficult optimization problem. In the paper proposes a new scheduling algorithm and compares with a
different scheduling traditional algorithms that are proportional fair and round robin in the CA, in order to
find the best scheduler that provides high-quality throughput and improves fairness. It also evaluates
mapping model types are Mutual Information Effective SINR Mapping (MIESM) and Exponential Effective
SINR Mapping (EESM). The results show that the throughput in the proposed algorithm with MIESM
outperforms from others mapping and scheduling.
Multiple Downlink Fair Packet Scheduling Scheme in Wi-MaxEditor IJCATR
IEEE 802.16 is standardization for a broadband wireless access in network metropolitan area network (MAN). IEEE 802.16
standard (Wi-Max) defines the concrete quality of service (QoS) requirement, a scheduling scheme and efficient packet scheduling
scheme which is necessary to achieve the QoS requirement. In this paper, a novel waiting queue based on downlink bandwidth
allocation architecture from a number of rtps schedule has been proposed to improve the performance of nrtPS services without any
impaction to other services. This paper proposes an efficient QoS scheduling scheme that satisfies both throughput and delay guarantee
to various real and non-real applications corresponding to different scheduling schemes for k=1,2,3,4. Simulation results show that
proposed scheduling scheme can provide a tight QoS guarantee in terms of delay for all types of traffic as defined in WiMax standards.
This process results in maintaining the fairness of allocation and helps to eliminate starvation of lower priority class services. The
authors propose a new efficient and generalized scheduling schemes for IEEE 802.16 broadband wireless access system reflecting the
delay requirements.
3GPP has introduced LTE Femtocells to manipulate the traffic for indoor users and to minimize
the charge on the Macro cells. A key mechanism in the LTE traffic handling is the packet
scheduler which is in charge of allocating resources to active flows in both the frequency and
time dimension. So several scheduling algorithms need to be analyzed for femtocells networks.
In this paper we introduce a performance analysis of three distinct scheduling algorithms of
mixed type of traffic flows in LTE femtocells networks. The particularly study is evaluated in
terms of throughput, packet loss ratio, fairness index and spectral efficiency.
This document summarizes a research paper that proposes using a hybrid of simulated annealing algorithm and fuzzy rule base system (SA-FRBS) for adaptive coding, modulation, and power allocation in orthogonal frequency-division multiplexing (OFDM) systems. The paper first discusses related work on using evolutionary algorithms like genetic algorithms for adaptive resource allocation in OFDM. It then describes the system model and analyzes the performance of different modulation and coding schemes. Next, it formulates the rate optimization problem and describes the design of the FRBS for selecting the optimal modulation-coding pairs. Finally, it compares the performance of the proposed SA-FRBS approach through simulations.
This document discusses adaptive multistreaming over a network using the Stream Control Transmission Protocol (SCTP). It proposes adapting the number of streams based on estimates of available bandwidth and current congestion window size to improve performance under congestion. The performance of this adaptive streams mechanism is evaluated through computer simulation using the OMNeT++ network simulation tool and INET framework. Simulation results are compared between the proposed adaptive streams approach and normal SCTP streaming.
Analytical average throughput and delay estimations for LTESpiros Louvros
This document summarizes an article that appeared in a journal published by Elsevier. The article proposes an analytical model to estimate average throughput and packet transmission delay for uplink cell edge users in LTE networks. The model uses probability analysis and mathematical modeling to estimate transmission delay and throughput, providing cell planners with an analytical tool for evaluating uplink performance under different conditions. The model accounts for factors like scheduling decisions, resource allocation, channel conditions and buffering that impact transmission delay and throughput for cell edge users.
FREQUENCY AND TIME DOMAIN PACKET SCHEDULING BASED ON CHANNEL PREDICTION WITH ...ijwmn
1) The document discusses packet scheduling algorithms for LTE downlink systems that must operate under imperfect channel quality information (CQI) due to errors, delays, and other issues.
2) It proposes a new packet scheduling algorithm that uses a Kalman filter-based channel predictor in the frequency domain to estimate the true CQI from erroneous feedback, combined with a time domain grouping technique using proportional fair and modified largest weighted delay first algorithms.
3) Simulation results showed this approach achieves better performance than existing algorithms in terms of system throughput and packet loss ratio under imperfect CQI conditions.
Extensive Reviews of OSPF and EIGRP Routing Protocols based on Route Summariz...IJERA Editor
The increasing demand of computer networks is growing rapidly day by day. The growing need to distribute applications across multiple networks with high capacity and high-performance intermediate switching nodes and networks. This research primarily focuses on route redistribution and route summarization of different intra-domain routing protocols such as EIGRP and OSPF. Routing Protocols that use facilitate to exchange routing information between routers. Reasons such as multiple departments managed by multiple network Administrators, company mergers. In any case, having a multiple routing protocol and different autonomous system in networks then without route redistribution we cannot advertise route from source to destination. Of course Network complexity will increase with the size of routing table of routers then route summarization is necessity, to reduce traffic and complexity of network.
Channel Aware Mac Protocol for Maximizing Throughput and FairnessIJORCS
The proper channel utilization and the queue length aware routing protocol is a challenging task in MANET. To overcome this drawback we are extending the previous work by improving the MAC protocol to maximize the Throughput and Fairness. In this work we are estimating the channel condition and Contention for a channel aware packet scheduling and the queue length is also calculated for the routing protocol which is aware of the queue length. The channel is scheduled based on the channel condition and the routing is carried out by considering the queue length. This queue length will provide a measurement of traffic load at the mobile node itself. Depending upon this load the node with the lesser load will be selected for the routing; this will effectively balance the load and improve the throughput of the ad hoc network.
This document discusses simulations of the physical layer of LTE networks. It specifically focuses on simulations of the Physical Downlink Shared Channel (PDSCH). The simulations are performed using the LTE System Toolbox from Mathworks. Throughput and bit error rate are measured for the PDSCH under various simulation setups and channel conditions. The results show that throughput increases and becomes sustained as SNR increases. Bit error rate curves also drop quickly with higher SNR. These simulations provide insight into the expected performance of LTE devices over the PDSCH.
Joint Routing and Congestion Control in Multipath Channel based on Signal to ...IJECEIAES
Routing protocol and congestion control in Transmission Control Protocol (TCP) have important roles in wireless mobile network performance. In wireless communication, the stability of the path and successful data transmission will be influenced by the channel condition. This channel condition constraints come from path loss and the multipath channel fading. With these constraints, the algorithm in the routing protocol and congestion control is confronted with the uncertainty of connection quality and probability of successful packet transmission, respectively. It is important to investigate the reliability and robustness of routing protocol and congestion control algorithms in dealing with such situation. In this paper, we develop a detailed approach and analytical throughput performance with a cross layer scheme (CLS) between routing and congestion control mechanism based on signal to noise ratio (SNR) in Rician and Rayleigh as multipath fading channel. We proposed joint routing and congestion control TCP with a cross layer scheme model based on SNR (RTCP-SNR). We compare the performance of RTCP-SNR with conventional routing-TCP and routing-TCP that used CLS with routing aware (RTCP-RA) model. The analyses and the simulation results showed that RTCP-SNR in a multipath channel outperforms conventional routing-TCP and RTCP-RA.
Throughput and Handover Latency Evaluation for Multicast Proxy Mobile IPV6journalBEEI
The objective of this paper is to present performance analysis of a new enhanced mobile multicast network mobility management scheme. The initial developed network mobility management called Proxy Mobile IPv6 (PMIPv6) is based on unicast network support. This paper enabled multicast support in network mobility management and named it as MPMIPv6. Additionally this enhancement also provides better network performance with the new context transfer operations and fast reroute operations. In brief, this paper also describes other current mobile multicast schemes. The new scheme is evaluated using mathematical analysis and NS3.19 simulator. Theoretically this scheme reduces service recovery time, total signalling cost, handover latency, and packet loss for multicast communication. However for this paper, the analysed parameters are throughput and handover latency. Both mathematical and simulation results exhibit better network performance for multicast environment compared to the standard benchmark scheme.
This document analyzes the performance of LTE networks using random linear network coding (RLNC) at the application layer. The study uses a simulation setup with a remote host, eNodeB, and user equipment to send coded and uncoded packets. The results show that applying RLNC at the application layer improves throughput but increases packet delay compared to not using network coding. MIMO antenna techniques are also found to provide higher throughput than SISO.
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
GA Based Optimization in LTE for Different Data with Different LoadsIRJET Journal
This document proposes using a genetic algorithm for cross-layer resource allocation in an LTE downlink multi-user OFDM system with heterogeneous traffic. The genetic algorithm is used to maximize the weighted sum capacity of multiple traffic queues by optimizing physical layer resource allocation like subcarrier and power allocation. Simulation results show the genetic algorithm approach significantly outperforms existing algorithms in terms of system bandwidth efficiency and delay for best effort and quality of service traffic.
Rm literature survey_on_scheduling_and_resource_allocation_for_ieee_80211ax_p...RESHAN FARAZ
This document summarizes literature on scheduling and resource allocation algorithms for IEEE 802.11ax wireless networks. It discusses key features of 802.11ax like OFDMA and higher modulation schemes. It then reviews several papers that propose algorithms using buffer status reports, grouping, and optimized resource unit allocation to improve throughput in dense environments. Overall resource allocation and scheduling remain challenging areas of research for fully utilizing 802.11ax capabilities and achieving high average throughput.
VIRTUAL ROUTING FUNCTION DEPLOYMENT IN NFV-BASED NETWORKS UNDER NETWORK DELAY...IJCNC Journal
NFV-based network implements a variety of network functions with software on general-purpose servers
and this allows the network operator to select any capacity and location of network functions without any
physical constraints. The authors proposed an algorithm of virtual routing function allocation in the NFVbased
network for minimizing the total power consumption or the total network cost, and developed
effective allocation guidelines for virtual routing functions.
This paper evaluates the effect of the maximum tolerable network delay on the guidelines for the allocation
of virtual routing functions, which minimizes the total network cost. The following points are clear from
quantitative evaluations: (1) The shorter the maximum tolerable network delay, the greater the number of
areas where the routing function must be allocated, resulting in an increase in the total network cost. (2)
The greater the routing function cost relative to the circuit bandwidth cost, the greater the increase in the
total network cost caused by the maximum tolerable network delay. This paper also provides the possible
guideline how to decide the value of maximum tolerable network delay when the condition of allowable
increase in network cost is given.
1 improvement of tcp congestion window over ltetanawan44
This document discusses improving the performance of TCP congestion control over LTE-Advanced networks. It proposes a new congestion avoidance mechanism that uses the available bandwidth of the connection to better detect the network path capacity and improve congestion avoidance. The mechanism is tested using the NS-2 network simulator to model LTE-Advanced traffic. The document provides background on LTE-Advanced network architecture and existing TCP congestion control mechanisms. It aims to develop an enhanced TCP variant that can efficiently transfer high data rates over the large bandwidth, low latency links of LTE-Advanced networks.
In order enhance the network efficiency of Mobile ad hoc Networks (MANETs), an Power Unbiased Cooperative Media Access Control(PUC-MAC) protocol in MANETs was planned during this paper. It adopted the most effective partnership choice statement to select the cooperative node with higher channel condition, higher passing rate and additional balanced power consumption. Simulation results showed that PUC-MAC outperforms EC-MAC,Cooperative MAC (CoopMAC) and IEEE 802.11 Distributed Coordination perform (DCF) in terms of the packet release quantitative relation, network outturn and network lifespan beneath 2 distinct channel noise levels, particularly beneath the worst channel condition.
Application of N jobs M machine Job Sequencing Technique for MPLS Traffic Eng...CSCJournals
This paper discusses Traffic Engineering with Multi-Protocol Label Switching (MPLS) in an Internet Service Provider’s (ISP) network. In this paper, we first briefly describe MPLS, Constraint-based Routing, MPLS-TE, N jobs M machine Job sequencing technique and how to implement the job sequencing technique for Multi-Protocol Label Switching Traffic Engineering. And also improve the quality of service of the network, using this technique firstly reduce the congestion for traffic engineering; minimize the packet loss in complex MPLS domain. In small network packet loss is negligible. We used NS2 discrete event simulator for simulate the above work. Keywords: Traffic Engineering, Multi-Protocol Label Switching, Constraint based routing, N jobs M machine Job Sequencing Technique, Qos, MPLS-TE.
This document summarizes a study on analyzing link weight performance in intra-domain networks. It discusses measuring network topology and traffic, modeling path selection based on IGP configuration, and controlling the network by reconfiguring IGP link weights. The goal is to optimize routing within existing protocols like OSPF to improve traffic flow based on measured conditions. Link weights are adjusted to balance loads and steer traffic onto preferable paths between routers within an autonomous system or domain.
PERFORMANCE COMPARISON OF PACKET SCHEDULING ALGORITHMS FOR VIDEO TRAFFIC IN L...ijmnct
In this paper we have studied downlink packet scheduling algorithms proposed for LTE cellular networks.
The study emphasize on three most promising scheduling algorithms such as: FLS, EXP rule and LOG rule.
The performance of these three algorithms is conducted over video traffic in a vehicular environment using
LTE-Sim simulator. The simulation was setup with varying number of users from 10 - 60 in fixed bounded
regions of 1 km radius. The main goal this study is to provide results that will help in the design process of
packet scheduler for LTE cellular networks, aiming to get better overall performance users. Simulation
results show that, the FLS scheme outperforms in terms of average system throughput, average packet
delay, PLR; and with a satisfactory level of fairness index.
A MANET is an autonomous collection of mobile users that communicate over relatively bandwidth constrained wireless links. When designing mobile ad hoc networks, several interesting and difficult problems arise because of the shared nature of the wireless medium, limited transmission power (range) of wireless devices, node mobility, and battery limitations. This paper aims at providing a new schema to improve Dynamic Source Routing (DSR) Protocol. The aim
behind the proposed enhancement is to find the best route in acceptable time limit without having broadcast storm. Moreover, O-DSR enables network not only to overcome congestion but also maximize the lifetime of mobile nodes. Some simulations results show that the Route Request (RREQ) and the Control Packet Overhead decrease by 15% when O-DSR is used, consequently. Also the global energy consumption in O-DSR is lower until to 60 % , which leads to a long lifetime of the network.
Solving bandwidth guaranteed routing problem using routing dataIJCNCJournal
This paper introduces a traffic engineering routing algorithm that aims to accept as many routing demands
as possible on the condition that a certain amount of bandwidth resource is reserved for each accepted
demand. The novel idea is to select routes based on not only network states but also information derived
from routing data such as probabilities of the ingress egress pairs and usage frequencies of the links.
Experiments with respect to acceptance ratio and computation time have been conducted against various
test sets. Results indicate that the proposed algorithm has better performance than the existing popular algorithms including Minimum Interference Routing Algorithm (MIRA) and Random Race based Algorithm for Traffic Engineering (RRATE)
.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
PERFORMANCE ANALYSIS OF RESOURCE SCHEDULING IN LTE FEMTOCELLS NETWORKScscpconf
3GPP has introduced LTE Femtocells to manipulate the traffic for indoor users and to minimize the charge on the Macro cells. A key mechanism in the LTE traffic handling is the packet
scheduler which is in charge of allocating resources to active flows in both the frequency and time dimension. So several scheduling algorithms need to be analyzed for femtocells networks. In this paper we introduce a performance analysis of three distinct scheduling algorithms of mixed type of traffic flows in LTE femtocells networks. The particularly study is evaluated in terms of throughput, packet loss ratio, fairness index and spectral efficiency.
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.
Survey on scheduling and radio resources allocation in lteijngnjournal
- The document discusses scheduling and radio resource allocation in LTE networks. It focuses on the radio resource manager (RRM) element in LTE that performs admission control and packet scheduling.
- Several scheduling algorithms are proposed for both uplink and downlink directions, including proportional fair, EXP-PF, round robin, max-min fair, and algorithms that aim to maximize throughput or support quality of service requirements.
- The paper provides an overview of these scheduling algorithms, evaluates their performance, and offers criticism on how to best allocate radio resources in LTE networks.
Adaptive Routing in Wireless Sensor Networks: QoS Optimisation for Enhanced A...M H
The document describes a new routing protocol called Route Optimization and Load-balancing (ROL) for wireless sensor networks. ROL aims to balance several objectives like prolonging network lifetime, providing timely message delivery, and improving network robustness. It uses a combination of routing metrics that can be configured according to application priorities to optimize overall network performance. Simulation results show that ROL maintains balanced cluster sizes and populations, reduces overhead, end-to-end delays, and improves data delivery ratios compared to other protocols like Mires++.
Extensive Reviews of OSPF and EIGRP Routing Protocols based on Route Summariz...IJERA Editor
The increasing demand of computer networks is growing rapidly day by day. The growing need to distribute applications across multiple networks with high capacity and high-performance intermediate switching nodes and networks. This research primarily focuses on route redistribution and route summarization of different intra-domain routing protocols such as EIGRP and OSPF. Routing Protocols that use facilitate to exchange routing information between routers. Reasons such as multiple departments managed by multiple network Administrators, company mergers. In any case, having a multiple routing protocol and different autonomous system in networks then without route redistribution we cannot advertise route from source to destination. Of course Network complexity will increase with the size of routing table of routers then route summarization is necessity, to reduce traffic and complexity of network.
Channel Aware Mac Protocol for Maximizing Throughput and FairnessIJORCS
The proper channel utilization and the queue length aware routing protocol is a challenging task in MANET. To overcome this drawback we are extending the previous work by improving the MAC protocol to maximize the Throughput and Fairness. In this work we are estimating the channel condition and Contention for a channel aware packet scheduling and the queue length is also calculated for the routing protocol which is aware of the queue length. The channel is scheduled based on the channel condition and the routing is carried out by considering the queue length. This queue length will provide a measurement of traffic load at the mobile node itself. Depending upon this load the node with the lesser load will be selected for the routing; this will effectively balance the load and improve the throughput of the ad hoc network.
This document discusses simulations of the physical layer of LTE networks. It specifically focuses on simulations of the Physical Downlink Shared Channel (PDSCH). The simulations are performed using the LTE System Toolbox from Mathworks. Throughput and bit error rate are measured for the PDSCH under various simulation setups and channel conditions. The results show that throughput increases and becomes sustained as SNR increases. Bit error rate curves also drop quickly with higher SNR. These simulations provide insight into the expected performance of LTE devices over the PDSCH.
Joint Routing and Congestion Control in Multipath Channel based on Signal to ...IJECEIAES
Routing protocol and congestion control in Transmission Control Protocol (TCP) have important roles in wireless mobile network performance. In wireless communication, the stability of the path and successful data transmission will be influenced by the channel condition. This channel condition constraints come from path loss and the multipath channel fading. With these constraints, the algorithm in the routing protocol and congestion control is confronted with the uncertainty of connection quality and probability of successful packet transmission, respectively. It is important to investigate the reliability and robustness of routing protocol and congestion control algorithms in dealing with such situation. In this paper, we develop a detailed approach and analytical throughput performance with a cross layer scheme (CLS) between routing and congestion control mechanism based on signal to noise ratio (SNR) in Rician and Rayleigh as multipath fading channel. We proposed joint routing and congestion control TCP with a cross layer scheme model based on SNR (RTCP-SNR). We compare the performance of RTCP-SNR with conventional routing-TCP and routing-TCP that used CLS with routing aware (RTCP-RA) model. The analyses and the simulation results showed that RTCP-SNR in a multipath channel outperforms conventional routing-TCP and RTCP-RA.
Throughput and Handover Latency Evaluation for Multicast Proxy Mobile IPV6journalBEEI
The objective of this paper is to present performance analysis of a new enhanced mobile multicast network mobility management scheme. The initial developed network mobility management called Proxy Mobile IPv6 (PMIPv6) is based on unicast network support. This paper enabled multicast support in network mobility management and named it as MPMIPv6. Additionally this enhancement also provides better network performance with the new context transfer operations and fast reroute operations. In brief, this paper also describes other current mobile multicast schemes. The new scheme is evaluated using mathematical analysis and NS3.19 simulator. Theoretically this scheme reduces service recovery time, total signalling cost, handover latency, and packet loss for multicast communication. However for this paper, the analysed parameters are throughput and handover latency. Both mathematical and simulation results exhibit better network performance for multicast environment compared to the standard benchmark scheme.
This document analyzes the performance of LTE networks using random linear network coding (RLNC) at the application layer. The study uses a simulation setup with a remote host, eNodeB, and user equipment to send coded and uncoded packets. The results show that applying RLNC at the application layer improves throughput but increases packet delay compared to not using network coding. MIMO antenna techniques are also found to provide higher throughput than SISO.
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
GA Based Optimization in LTE for Different Data with Different LoadsIRJET Journal
This document proposes using a genetic algorithm for cross-layer resource allocation in an LTE downlink multi-user OFDM system with heterogeneous traffic. The genetic algorithm is used to maximize the weighted sum capacity of multiple traffic queues by optimizing physical layer resource allocation like subcarrier and power allocation. Simulation results show the genetic algorithm approach significantly outperforms existing algorithms in terms of system bandwidth efficiency and delay for best effort and quality of service traffic.
Rm literature survey_on_scheduling_and_resource_allocation_for_ieee_80211ax_p...RESHAN FARAZ
This document summarizes literature on scheduling and resource allocation algorithms for IEEE 802.11ax wireless networks. It discusses key features of 802.11ax like OFDMA and higher modulation schemes. It then reviews several papers that propose algorithms using buffer status reports, grouping, and optimized resource unit allocation to improve throughput in dense environments. Overall resource allocation and scheduling remain challenging areas of research for fully utilizing 802.11ax capabilities and achieving high average throughput.
VIRTUAL ROUTING FUNCTION DEPLOYMENT IN NFV-BASED NETWORKS UNDER NETWORK DELAY...IJCNC Journal
NFV-based network implements a variety of network functions with software on general-purpose servers
and this allows the network operator to select any capacity and location of network functions without any
physical constraints. The authors proposed an algorithm of virtual routing function allocation in the NFVbased
network for minimizing the total power consumption or the total network cost, and developed
effective allocation guidelines for virtual routing functions.
This paper evaluates the effect of the maximum tolerable network delay on the guidelines for the allocation
of virtual routing functions, which minimizes the total network cost. The following points are clear from
quantitative evaluations: (1) The shorter the maximum tolerable network delay, the greater the number of
areas where the routing function must be allocated, resulting in an increase in the total network cost. (2)
The greater the routing function cost relative to the circuit bandwidth cost, the greater the increase in the
total network cost caused by the maximum tolerable network delay. This paper also provides the possible
guideline how to decide the value of maximum tolerable network delay when the condition of allowable
increase in network cost is given.
1 improvement of tcp congestion window over ltetanawan44
This document discusses improving the performance of TCP congestion control over LTE-Advanced networks. It proposes a new congestion avoidance mechanism that uses the available bandwidth of the connection to better detect the network path capacity and improve congestion avoidance. The mechanism is tested using the NS-2 network simulator to model LTE-Advanced traffic. The document provides background on LTE-Advanced network architecture and existing TCP congestion control mechanisms. It aims to develop an enhanced TCP variant that can efficiently transfer high data rates over the large bandwidth, low latency links of LTE-Advanced networks.
In order enhance the network efficiency of Mobile ad hoc Networks (MANETs), an Power Unbiased Cooperative Media Access Control(PUC-MAC) protocol in MANETs was planned during this paper. It adopted the most effective partnership choice statement to select the cooperative node with higher channel condition, higher passing rate and additional balanced power consumption. Simulation results showed that PUC-MAC outperforms EC-MAC,Cooperative MAC (CoopMAC) and IEEE 802.11 Distributed Coordination perform (DCF) in terms of the packet release quantitative relation, network outturn and network lifespan beneath 2 distinct channel noise levels, particularly beneath the worst channel condition.
Application of N jobs M machine Job Sequencing Technique for MPLS Traffic Eng...CSCJournals
This paper discusses Traffic Engineering with Multi-Protocol Label Switching (MPLS) in an Internet Service Provider’s (ISP) network. In this paper, we first briefly describe MPLS, Constraint-based Routing, MPLS-TE, N jobs M machine Job sequencing technique and how to implement the job sequencing technique for Multi-Protocol Label Switching Traffic Engineering. And also improve the quality of service of the network, using this technique firstly reduce the congestion for traffic engineering; minimize the packet loss in complex MPLS domain. In small network packet loss is negligible. We used NS2 discrete event simulator for simulate the above work. Keywords: Traffic Engineering, Multi-Protocol Label Switching, Constraint based routing, N jobs M machine Job Sequencing Technique, Qos, MPLS-TE.
This document summarizes a study on analyzing link weight performance in intra-domain networks. It discusses measuring network topology and traffic, modeling path selection based on IGP configuration, and controlling the network by reconfiguring IGP link weights. The goal is to optimize routing within existing protocols like OSPF to improve traffic flow based on measured conditions. Link weights are adjusted to balance loads and steer traffic onto preferable paths between routers within an autonomous system or domain.
PERFORMANCE COMPARISON OF PACKET SCHEDULING ALGORITHMS FOR VIDEO TRAFFIC IN L...ijmnct
In this paper we have studied downlink packet scheduling algorithms proposed for LTE cellular networks.
The study emphasize on three most promising scheduling algorithms such as: FLS, EXP rule and LOG rule.
The performance of these three algorithms is conducted over video traffic in a vehicular environment using
LTE-Sim simulator. The simulation was setup with varying number of users from 10 - 60 in fixed bounded
regions of 1 km radius. The main goal this study is to provide results that will help in the design process of
packet scheduler for LTE cellular networks, aiming to get better overall performance users. Simulation
results show that, the FLS scheme outperforms in terms of average system throughput, average packet
delay, PLR; and with a satisfactory level of fairness index.
A MANET is an autonomous collection of mobile users that communicate over relatively bandwidth constrained wireless links. When designing mobile ad hoc networks, several interesting and difficult problems arise because of the shared nature of the wireless medium, limited transmission power (range) of wireless devices, node mobility, and battery limitations. This paper aims at providing a new schema to improve Dynamic Source Routing (DSR) Protocol. The aim
behind the proposed enhancement is to find the best route in acceptable time limit without having broadcast storm. Moreover, O-DSR enables network not only to overcome congestion but also maximize the lifetime of mobile nodes. Some simulations results show that the Route Request (RREQ) and the Control Packet Overhead decrease by 15% when O-DSR is used, consequently. Also the global energy consumption in O-DSR is lower until to 60 % , which leads to a long lifetime of the network.
Solving bandwidth guaranteed routing problem using routing dataIJCNCJournal
This paper introduces a traffic engineering routing algorithm that aims to accept as many routing demands
as possible on the condition that a certain amount of bandwidth resource is reserved for each accepted
demand. The novel idea is to select routes based on not only network states but also information derived
from routing data such as probabilities of the ingress egress pairs and usage frequencies of the links.
Experiments with respect to acceptance ratio and computation time have been conducted against various
test sets. Results indicate that the proposed algorithm has better performance than the existing popular algorithms including Minimum Interference Routing Algorithm (MIRA) and Random Race based Algorithm for Traffic Engineering (RRATE)
.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
PERFORMANCE ANALYSIS OF RESOURCE SCHEDULING IN LTE FEMTOCELLS NETWORKScscpconf
3GPP has introduced LTE Femtocells to manipulate the traffic for indoor users and to minimize the charge on the Macro cells. A key mechanism in the LTE traffic handling is the packet
scheduler which is in charge of allocating resources to active flows in both the frequency and time dimension. So several scheduling algorithms need to be analyzed for femtocells networks. In this paper we introduce a performance analysis of three distinct scheduling algorithms of mixed type of traffic flows in LTE femtocells networks. The particularly study is evaluated in terms of throughput, packet loss ratio, fairness index and spectral efficiency.
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.
Survey on scheduling and radio resources allocation in lteijngnjournal
- The document discusses scheduling and radio resource allocation in LTE networks. It focuses on the radio resource manager (RRM) element in LTE that performs admission control and packet scheduling.
- Several scheduling algorithms are proposed for both uplink and downlink directions, including proportional fair, EXP-PF, round robin, max-min fair, and algorithms that aim to maximize throughput or support quality of service requirements.
- The paper provides an overview of these scheduling algorithms, evaluates their performance, and offers criticism on how to best allocate radio resources in LTE networks.
Adaptive Routing in Wireless Sensor Networks: QoS Optimisation for Enhanced A...M H
The document describes a new routing protocol called Route Optimization and Load-balancing (ROL) for wireless sensor networks. ROL aims to balance several objectives like prolonging network lifetime, providing timely message delivery, and improving network robustness. It uses a combination of routing metrics that can be configured according to application priorities to optimize overall network performance. Simulation results show that ROL maintains balanced cluster sizes and populations, reduces overhead, end-to-end delays, and improves data delivery ratios compared to other protocols like Mires++.
This document analyzes the performance of the LTE physical layer under 3GPP standards parameters. It summarizes an analysis of downlink and uplink throughput for LTE operating in both FDD and TDD modes with different system bandwidths, antenna configurations, modulation schemes, and coding rates. The key results showed that LTE can support downlink throughputs up to 300Mbps with 20MHz bandwidth using MIMO 4x4, and uplink throughputs up to 75Mbps.
Multipoint Relay Path for Efficient Topology Maintenance Algorithm in Optimiz...IJCNCJournal
The Optimal Link State Routing (OLSR) protocol employs multipoint relay (MPR) nodes to disseminate topology control (TC) messages, enabling network topology discovery and maintenance. However, this approach increases control overhead and leads to wasted network bandwidth in stable topology scenarios due to fixed flooding periods. To address these challenges, this paper presents an Efficient Topology Maintenance Algorithm (ETM-OLSR) for Enhanced Link-State Routing Protocols. By reducing the number of MPR nodes, TC message generation and forwarding frequency are minimized. Furthermore, the algorithm selects a smaller subset of TC messages based on the changes in the MPR selection set from the previous cycle, adapting to stable and fluctuating network conditions. Additionally, the sending cycle of TC messages is dynamically adjusted in response to network topology changes. Simulation results demonstrate that the ETM-OLSR algorithm effectively reduces network control overhead, minimizes end-to-end delay, and improves network throughput compared to traditional OLSR and HTR-OLSR algorithms.
Multipoint Relay Path for Efficient Topology Maintenance Algorithm in Optimiz...IJCNCJournal
The Optimal Link State Routing (OLSR) protocol employs multipoint relay (MPR) nodes to disseminate topology control (TC) messages, enabling network topology discovery and maintenance. However, this approach increases control overhead and leads to wasted network bandwidth in stable topology scenarios due to fixed flooding periods. To address these challenges, this paper presents an Efficient Topology Maintenance Algorithm (ETM-OLSR) for Enhanced Link-State Routing Protocols. By reducing the number of MPR nodes, TC message generation and forwarding frequency are minimized. Furthermore, the algorithm selects a smaller subset of TC messages based on the changes in the MPR selection set from the previous cycle, adapting to stable and fluctuating network conditions. Additionally, the sending cycle of TC messages is dynamically adjusted in response to network topology changes. Simulation results demonstrate that the ETM-OLSR algorithm effectively reduces network control overhead, minimizes end-to-end delay, and improves network throughput compared to traditional OLSR and HTR-OLSR algorithms.
- The first article proposes a new packet length optimization technique called DPLC for wireless sensor networks. DPLC dynamically adjusts packet lengths depending on distance and power to improve energy efficiency. It describes the DPLC design and evaluates its performance through testing.
- The second article describes MT-Deluge, a multithreaded design for efficient information dissemination in wireless sensor networks. It separates coding and radio operations into different threads to allow concurrent processing and reduce dissemination delays. Testing shows MT-Deluge improves energy efficiency over existing approaches.
- The third article discusses issues with the existing FlexRay automotive communication protocol. It proposes a cooperative scheduling scheme called CoEfficient to address problems like data loss and delays. CoEfficient
In this paper, we propose a new traffic flow model of the Long Term Evaluation (LTE) network for the Evolved Universal Terrestrial Radio Access Network (E-UTRAN). Here only one Evolve Node B (eNB) nearest to the Mobility Management Entity (MME) and Serving Gateway (S-GW) will use the S1 link to bridge the E-UTRAN and Evolved Packet Core (EPC). All the eNBs of a tracking area will be connected to each other by the X2 link. Determination of capacity of a links of such a network is a challenging job since each node offers its own traffic and at the same time conveys traffic of other nodes. In this paper, we apply maximum flow algorithm including superposition theorem to solve the traffic flow of radio network. Using the total flow per subcarrier, a new traffic model is also developed in the paper. The relation among the traffic parameters: ‘blocking probability’, ‘offered traffic’, ‘instantaneous capacity’, ‘average holding time’, and ‘number of users’ are shown graphically under both QPSK and 16-QAM. The concept of the network will be helpful to improve the SINR of the received signal ofeNBslocated long distance relative to MME/S-GW.
PERFORMANCE EVALUATION OF LTE NETWORK USING MAXIMUM FLOW ALGORITHMijcsit
In this paper, we propose a new traffic flow model of the Long Term Evaluation (LTE) network for the Evolved Universal Terrestrial Radio Access Network (E-UTRAN). Here only one Evolve Node B (eNB) nearest to the Mobility Management Entity (MME) and Serving Gateway (S-GW) will use the S1 link to
bridge the E-UTRAN and Evolved Packet Core (EPC). All the eNBs of a tracking area will be connected to each other by the X2 link. Determination of capacity of a links of such a network is a challenging job since each node offers its own traffic and at the same time conveys traffic of other nodes. In this paper, we apply maximum flow algorithm including superposition theorem to solve the traffic flow of radio network. Using the total flow per subcarrier, a new traffic model is also developed in the paper. The relation among the traffic parameters: ‘blocking probability’, ‘offered traffic’, ‘instantaneous capacity’, ‘average holding
time’, and ‘number of users’ are shown graphically under both QPSK and 16-QAM. The concept of the network will be helpful to improve the SINR of the received signal ofeNBslocated long distance relative to MME/S-GW.
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.
B ENCHMARKING OF C ELL T HROUGHPUT U SING P ROPORTIONAL F AIR S CHEDULE...ijwmn
The proportional fair (PF) scheduling algorithm com
promises between cell throughput and fairness. Many
research findings have been published by various re
searchers about PF algorithm based on mathematical
model and simulations. In this paper we have taken
the practical route to analyse the algorithm based
on
three types of subscription. In this benchmarking s
tudy, the user subscriptions are differentiated as
Gold,
Silver and Bronze schemes and they are provisioned
with certain throughputs. Apart from subscriptions
plans, the channel condition also plays a major rol
e in determining the throughput. So in order to ens
ure
fairness among different subscriptions even in the
bad channel conditions and to deliver the provision
ed
throughputs certain priorities are attached with th
e subscriptions. As per the subscription plans Gold
subscribers are assigned with 50% of the speed offe
red by the network as maximum based on CAT3 speed
(100 Mbps in DL and 50 Mbps in UL), Silver is assig
ned with 25% of the max speed and Bronze is
assigned with 12% of the max speed. The priorities
assigned to subscribers determines the fairness in
the
unfavourable channel conditions - Bronze (high), Si
lver and Gold (medium). In this paper, an
benchmarking tests have been performed with all of
three types of subscribers for nearly two hours in
the
live single cell network without any heterogeneous
cells influencing it. Furthermore, the results are
compared with the simulation results.
Traffic offloading impact on the performanceIJCNCJournal
Long Term Evolution (LTE) is defined by the Third Generation Partnership Project (3GPP) standards as
Release 8/9. The LTE supports at max 20 MHz channel bandwidth for a carrier. The number of LTE users
and their applications are increasing, which increases the demand on the system BW. A new feature of the
LTE-Advanced (LTE-A) which is defined in the 3GPP standards as Release 10/11 is called Carrier Aggregation (CA), this feature allows the network to aggregate more carriers in-order to provide a higher bandwidth. Carrier Aggregation has three main cases: Intra-band contiguous, Intra-band non-contiguous, Inter-band contiguous. In addition to the Carrier Aggregation feature, LTE-A supports Heterogeneous Networks (HetNets). HetNets consists of a mix of macro-cells, remote radio heads, and low power nodes such as pico-cells, and femto-cells. HetNets allow cellular network operators to support higher data traffic
by offloading it to a smaller cells such as femto-cells. The aim of this paper is to evaluate the Quality of Service (QoS) performance of the Modified Largest Weighted Delay First (MLWDF), the Exponential Rule (Exp-Rule), and the Logarithmic Rule (Log-Rule) scheduling algorithms while offloading 50% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to ten femto-cells, and to compare it with the case in-which traffic offloading is not
applied. The QoS performance evaluation is based on the system's average throughput, Packet Loss Rate (PLR), average packet delay, and fairness among users. The LTE-Sim-5 with modifications is used in the simulation process. Simulation results show that offloading 100% of the Macro-cell's traffic to five femtocells had the highest maximum throughput, and the best PLR values especially when using the Log-Rule, in-which using it maintained the PLR values around 0.15 despite increasing the number of users. The least average packet delay was achieved when offloading 100% of the Macro-cell's traffic to ten femto-cells, the delay dropped to below 5 ms. The fairness indicators for the three scheduling algorithms while traffic
offloading was applied fluctuated in a linear way between a range of values of 0.7 and 0.9.
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.
This document summarizes a research paper that proposes a new cooperative channel load aware VoIP routing topology for 802.11 WLAN networks. It introduces the concept of cooperative channel transmitting technology for 802.11 WLAN networks and discusses some of the challenges in providing quality of service guarantees. It then presents a linear programming model and scheduling algorithm to implement cooperative channel transmissions while considering queue status and transitive node relationships to maximize throughput. Simulation results show that the proposed scheduling algorithm improves throughput and fairness compared to alternatives.
S URVEY OF L TE D OWNLINK S CHEDULERS A LGORITHMS IN O PEN A CCESS S IM...ijwmn
he LTE/LTE-A has become a catchphrase for research
and lot of research are being conducted and
carried out in LTE in various issues by various peo
ple. New tools are developed and introduced in the
market to interpret the results of the new algorith
ms proposed by various people. Some tools are open
access which are free to use but some tools are pro
duced by the companies which are not open access. I
n
this paper some of the open access simulation tools
like LTE-Sim and NS-3 are analyzed and LTE downlin
k
scheduler algorithms are simulated using those tool
s. In LTE systems, the downlink scheduler is an
important component for radio resource management;
hence in the context of LTE simulation, a study
between the downlink scheduler models between the s
imulators are performed.
Dynamic bandwidth allocation scheme in lr pon with performance modelling and ...IJCNCJournal
We consider models of telecommunication systems that incorporate probability, dense real-time and data.
We present a new formal abstraction method for computing minimum and maximum reachability
probabilities for such models. Our approach uses strictly local formal abstract steps to reduce both the size
of abstract specifications generated and the complexity of operations needed, in comparison to previous
approaches of this kind. A selection of large case studies are implemented the techniques and evaluate,
which include some infinite-state probabilistic real time models, demonstrating improvements over existing
tools in several cases. The capacity of metro and access networks are extended the reach and split ratio of
the conventional Long - Reach Passive Optical Networks (LR-PONs). The efficient solutions of LR-PONs
are appeared in feeder distances around 100km and high split ratios up to 1000-way . Among many
existing approaches, one of the most effective options to improve network performance in LR-PONs are the
multi-thread based dynamic bandwidth allocation (DBA) scheme where several bandwidth allocation
processes are performed in parallel is considered. Without proper intercommunication between the
overlapped threads, multi-thread DBA may lose efficiency and even perform worse than the conventional
single thread algorithm. Real Time Probabilistic Systems are used to evaluate a typical PON systems
performance. This approach is more convenient, flexible, and lower cost than the former simulation method,
which do not need develop special hardware and software tools. Moreover, how changes in performance
depend on changes in the particular modes can be easily analysis by supplying ranges for parameter values.
The proposed algorithm with traditional DBA is compared, and shows its advantage on average packet
delay. The key parameters of the algorithm are analysed and optimized, such as initiating and tuning
multiple threads, inter -thread scheduling, and fairness among users. The algorithms advantage in
numerical results are decreased the average packet delay and improve network throughput under varying
offered loads.
ADAPTIVE HANDOVER HYSTERESIS AND CALL ADMISSION CONTROL FOR MOBILE RELAY NODESIJCNCJournal
The aim of equipping a wireless network with a mobile relay node is to support broadband wireless communications for vehicular users and their devices. The high mobility of vehicular users, possibly at a very high velocity in the area in which two cells overlap, could cause the network to suffer from a reduced handover success rate and, hence, increased radio link failure. The combined impact of these problems is service interruptions to vehicular users. Thus, the handover schemes are crucial in solving these problems. In this work, we first present the adaptive handover hysteresis scheme for the wireless network with mobile relay nodes in the high-speed train scenario. Specifically, our proposed adaptive hysteresis scheme is based on the velocity of the train. Second, the handover call dropping probability is reduced by introducing a modified call admission control scheme to support radio resource reservation for handover calls that prioritizes handover calls of mobile relay over the other calls. The proposed solution in which adaptive parameter is combined with call admission control is evaluated by system level simulation. Our simulation results illustrate an increased handover success rate and reduced radio link failures.
Efficient and Fair Bandwidth Allocation AQM Scheme for Wireless NetworksCSCJournals
Heterogeneous Wireless Networks are considered nowadays as one of the potential areas in research and development. The traffic management’s schemes that have been used at the fusion points between the different wireless networks are classical and conventional. This paper is focused on developing a novel scheme to overcome the problem of traffic congestion in the fusion point router interconnected the heterogeneous wireless networks. The paper proposed an EF-AQM algorithm which provides an efficient and fair allocation of bandwidth among different established flows. Finally, the proposed scheme developed, tested and validated through a set of experiments to demonstrate the relative merits and capabilities of a proposed scheme
QOS-B ASED P ERFORMANCE E VALUATION OF C HANNEL -A WARE /QOS-A WARE S CHEDULI...csandit
Long Term Evolution (LTE) is defined by the Third G
eneration Partnership Project (3GPP)
standards as Release 8/9. The LTE supports at max 2
0 MHz channel bandwidth for a carrier.
The number of LTE users and their applications are
increasing, which increases the demand on
the system BW. A new feature of the LTE-Advanced (L
TE-A) which is defined in the 3GPP
standards as Release 10/11 is called Carrier Aggreg
ation (CA), this feature allows the network
to aggregate more carriers in-order to provide a hi
gher bandwidth. Carrier Aggregation has
three main cases: Intra-band contiguous, Intra-band
non-contiguous, Inter-band contiguous.
The main contribution of this paper was in implemen
ting the Intra-band contiguous case by
modifying the LTE-Sim-5, then evaluating the Qualit
y of Service (QoS) performance of the
Modified Largest Weighted Delay First (MLWDF), the
Exponential Rule (Exp-Rule), and the
Logarithmic Rule (Log-Rule) scheduling algorithms
Similar to QoS-aware scheduling in LTE-A networks with SDN control (20)
A Route Selection Scheme for supporting Virtual Tours in Sites with Cultural ...University of Piraeus
This document proposes a route selection scheme for drones conducting virtual tours of cultural heritage sites. It uses two algorithms: 1) the Analytic Network Process to model user preferences for different monument types, and 2) the Trapezoidal Fuzzy TOPSIS method to rank candidate drone routes based on how well they cover monuments of interest while accounting for uncertainty. The proposed scheme applies fuzzy multiple attribute decision making to select the optimal route for providing users a satisfactory virtual tour experience tailored to their preferences. Performance evaluation shows it produces better results than existing fuzzy TOPSIS by choosing the most suitable flying route.
A Route Selection Scheme for supporting Virtual Tours in Sites with Cultural ...University of Piraeus
Virtual tourism is a novel trend that enhances the experience the users perceive from touristic places, such as archaeological sites. Drones are equipped with 360o video cameras and used for video capturing of the heritage sites. The video material is streamed to the users in real time, enriched with additional 3D, Augmented Reality (AR) or Mixed Reality (MR) material. Furthermore, the selection of the appropriate flying route for each drone should be performed, in order to provide a satisfactory tour experience to the user, considering his preferences about specific monuments. To address this issue, this paper describes a heritage route selection scheme for supporting real-time virtual tours in sites with cultural interest using drones. The proposed scheme applies a Fuzzy Multiple Attribute Decision Making (FMADM) algorithm, the Trapezoidal Fuzzy Topsis for Heritage Route Selection (TFT-HRS), to accomplish the ranking of the candidate heritage routes. The algorithm uses Interval-Valued Trapezoidal Fuzzy Numbers (IVTFN) for the representation of heritage routes evaluation values. Performance evaluation shows that the suggested method produces better results compared to the Fuzzy Topsis (FTOPSIS) by selecting the most appropriate flying route for the drone.
A VHO Scheme for supporting Healthcare Services in 5G Vehicular Cloud Computi...University of Piraeus
Fifth Generation Vehicular Cloud Computing (5G-VCC) systems use heterogeneous network access technologies in order to fulfill the requirements of modern services, including medical services with strict constraints. Therefore, the need for efficient Vertical Handover (VHO) management schemes must be addressed. In this paper, a VHO management scheme for supporting medical services in 5G-VCC systems, is described. It consists of the VHO initiation and the network selection processes, while at the same time, the vehicle’s velocity, its current connection type, as well as the status of the onboard patient’s health, are considered. Specifically, during the VHO initiation process the necessity to perform handover is evaluated. Subsequently, the network selection process selects the appropriate network alternative considering both medical service requirements and patients’ health status. The proposed scheme is applied to a 5G-VCC system which includes Long Term Evolution (LTE) and Worldwide Interoperability Microwave Access (WiMAX) Macrocells and Femtocells, as well as Wireless Access for Vehicular Environment Road Side Units (WAVE RSUs). Performance evaluation shows that the proposed algorithm outperforms existing VHO management schemes.
A Network Selection Scheme with Adaptive Criteria Weights for 5G Vehicular Sy...University of Piraeus
Fifth Generation Vehicular Cloud Computing (5G-VCC) systems use heterogeneous network access technologies to fulfill the requirements of modern vehicular services. Efficient network selection algorithms are required to satisfy the constraints of Driver Assistance (DA) services, Passengers Entertainment and Information (PEnI) services and Medical (MED) services that provided to vehicular users. The presence of MED services affects the importance of other services in situations where patients with immediate health status exist within the vehicle. This paper proposes a network selection scheme which considers the patient health status to adapt the importance of each service. The scheme consists of two Fuzzy Multi Attribute Decision Making (FMADM) algorithms: the Trapezoidal Fuzzy Adaptive Analytic Network Process (TF-AANP) to calculate the relative importance of each vehicular service and the selection criteria, as well as the Trapezoidal Fuzzy Topsis with Adaptive Criteria Weights (TFT-ACW) to accomplish the ranking of the candidate networks. Both algorithms use Interval-Valued Trapezoidal Fuzzy Numbers (IVTFN). Performance evaluation shows that the suggested method outperforms existing algorithms by satisfying the constraints of MED services when the patient health status becomes immediate.
A Network Selection Algorithm for supporting Drone Services in 5G Network Arc...University of Piraeus
Flying Ad-hoc Networks (FANETs) use 5G network access technologies to fulfill the requirements of their services. In this environment, Drone to Infrastructure (D2I) communication is supported, while each drone could use both Disaster Management (DM) and non-Disaster Management (nDM) services. Efficient network selection algorithms are required to satisfy the constraints of the used services, since the presence of DM services affects the importance of nDM services in situations where a natural disaster occurs. This paper proposes a network selection algorithm which is called Dynamic Trapezoidal Fuzzy Topsis with Adaptive Criteria Weights (DTFT-ACW). DTFT-ACW accomplishes the ranking of the candidate networks considering the importance of each service, as well as the weights of the corresponding selection criteria, as they are obtained with respect to the severity level of a natural disaster occurred. Interval-Valued Trapezoidal Fuzzy Numbers (IVTFN) are used for the criteria evaluation. Experimental results show that the suggested method outperforms existing algorithms by satisfying the constraints of DM services when a disaster becomes severe. Furthermore, DTFT-ACW eliminates the computational complexity of the network selection by considering past decisions.
A Network Selection Algorithm for supporting Drone Services in 5G Network Arc...University of Piraeus
Flying Ad-hoc Networks (FANETs) use 5G network access technologies to fulfill the requirements of their services. In this environment, Drone to Infrastructure (D2I) communication is supported, while each drone could use both Disaster Management (DM) and non-Disaster Management (nDM) services. Efficient network selection algorithms are required to satisfy the constraints of the used services, since the presence of DM services affects the importance of nDM services in situations where a natural disaster occurs. This paper proposes a network selection algorithm which is called Dynamic Trapezoidal Fuzzy Topsis with Adaptive Criteria Weights (DTFT-ACW). DTFT-ACW accomplishes the ranking of the candidate networks considering the importance of each service, as well as the weights of the corresponding selection criteria, as they are obtained with respect to the severity level of a natural disaster occurred. Interval-Valued Trapezoidal Fuzzy Numbers (IVTFN) are used for the criteria evaluation. Experimental results show that the suggested method outperforms existing algorithms by satisfying the constraints of DM services when a disaster becomes severe. Furthermore, DTFT-ACW eliminates the computational complexity of the network selection by considering past decisions.
A Survey on Medium Access Control Schemes for 5G Vehicular Cloud Computing Sy...University of Piraeus
Fifth generation (5G) vehicular systems support multiple services with strict Quality of Service (QoS) constraints. To fulfill the increased communication needs, 5G Vehicular Cloud Computing (5G-VCC) architectures with dense deployments of the access network infrastructures have been proposed. In such systems, the network resources manipulation is a critical task that could be addressed by the Medium Access Control (MAC) layer. MAC schemes that have been proposed for vehicular networks, can be applied to 5G-VCC systems in order optimal manipulation of communication resources to be accomplished. This paper makes an overview of available MAC schemes, while a comprehensive discussion about their implementation in 5G-VCC systems is performed leading to useful conclusions.
A Survey on Medium Access Control Schemes for 5G Vehicular Cloud Computing Sy...University of Piraeus
Fifth generation (5G) vehicular systems support multiple services with strict Quality of Service (QoS) constraints. To fulfill the increased communication needs, 5G Vehicular Cloud Computing (5G-VCC) architectures with dense deployments of the access network infrastructures have been proposed. In such systems, the network resources manipulation is a critical task that could be addressed by the Medium Access Control (MAC) layer. MAC schemes that have been proposed for vehicular networks, can be applied to 5G-VCC systems in order optimal manipulation of communication resources to be accomplished. This paper makes an overview of available MAC schemes, while a comprehensive discussion about their implementation in 5G-VCC systems is performed leading to useful conclusions.
The enhancement of Underwater Cultural Heritage Assets using Augmented Realit...University of Piraeus
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The revival of back-filled monuments through Augmented Reality (AR) (presenta...University of Piraeus
The development of three-dimensional (3D) models and the use of Augmented Reality (AR) in the field of cultural heritage consists an innovative process the recent years that provides the visitors of archaeological sites with additional information. This has been made possible due to achievements in digital technologies, communications, devices and developments in software engineering. Nevertheless, the research to fully make use of these new methods continues, as the potentials of new technologies have not been exploited. In archaeological sites, the production of 3D models for AR is focused on the virtual reconstruction of ruined monuments at their original form, aiming to give visitors the third dimension (height, volume etc.), especially to those who do not have special knowledge of archaeology. This paper describes an innovative approach of using AR for maintaining the memory and the information of monuments, as they have been originally excavated, but that are going to be back -filled due to the particularity of their material or their location. Also, the system architecture of the proposed scheme is described considering two study cases, a Neolithic settlement in the archaeological site of Halai, Lokris and the remains of a Classical Temple on open field of a hill in Thebes, Boeotia. Both mentioned monuments are under the direction of the American School of Classical Studies in Athens (ASCSA).
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Trusted Execution Environment for Decentralized Process Mining
QoS-aware scheduling in LTE-A networks with SDN control
1. QoS-aware scheduling in LTE-A networks with
SDN control
Emmanouil Skondras1, Angelos Michalas2, Aggeliki Sgora1, Dimitrios D. Vergados1
1
Department of Informatics, University of Piraeus, Piraeus, Greece, Email: {skondras, asgora, vergados}@unipi.gr
2
Department of Informatics Engineering, Technological Education Institute of Western Macedonia,
Kastoria, Greece, Email: amichalas@kastoria.teiwm.gr
Abstract—The 3GPP Long Term Evolution Advanced (LTE-A)
standard specifies a set of pioneer features such as relay nodes
and carrier aggregation. At the same time, the Software Defined
Networks (SDN) have become an emerging technology which
provides centralized control and programmability to modern
networks. In the current communication environment, cloud
computing could combine the advantages of both technologies
in order to create a novel cloud assisted Software Defined LTE-
A architecture with relay nodes. Moreover, due to the increased
requirements of modern services, the optimal resource allocation
is a necessity. In such a context, this paper describes a QoS
aware cross carrier scheduler for downlink flows, aiming at
the optimization of system resources allocation. The proposed
scheduler is evaluated against the PF, MLWDF, EXP/PF, EXP
RULE, LOG RULE, FLS and FLSA schedulers in a cloud assisted
Software Defined LTE-A topology with relay nodes. Simulation
results show that the proposed scheduler improves the real
time services performance while at the same time maintains an
acceptable performance for best effort flows.
I. INTRODUCTION
The LTE network technology uses an all-IP, purely packet-
switched architecture to provide high communication speeds
and satisfy the increased QoS requirements of modern ser-
vices. The first LTE release (rel. 8) [1] provides data rates up
to 100 Mbps for downlink and up to 50Mbps for uplink. In
such an architecture, information is transmitted in frames of
10ms of length and every frame is split into 10 sub-frames
of 1 Time Transmission Interval (TTI) of length each. The
minimum resource which can be allocated for transmission is
called Resource Block (RB). The scheduler assigns RBs to
users in each TTI and the number of available RBs per TTI
depends on the system bandwidth.
The LTE-A (rels. from 11 to 14) [2] significantly enhances
the rel. 8 specifications and improves the access network
capacity using evolved characteristics, such as Relay Nodes
(RNs) and Carrier Aggregation (CA) providing increased cov-
erage with rates up to 1Gbps for downlink and up to 500Mbps
for uplink. Relaying is one of the vital elements of LTE-A
to fulfill the users’ requirements on high data rate coverage.
Wireless small-range cells improve connectivity of mobile
users experiencing bad channel conditions within the coverage
area of an LTE base station (eNodeB). Relays are connected
to the backbone network by maintaining wireless connections
with the base station. Furthermore, using CA mode in LTE-
A, the system bandwidth is increased by aggregating up to
5 component carriers and thus having more available RBs for
scheduling in each TTI. The first component carrier is referred
as Primary Component Carrier (PCC) and the rest component
carriers are referred as Secondary Component Carriers (SCCs).
According to the Cross Carrier Scheduling (CCS) method-
ology, the PCC includes both a control region and a data
region, while each SCC includes only a data region. Regarding
the non-Cross Carrier Scheduling (n-CCS) operating principle
each PCC and SCC use their own control regions to allocate
RBs. Both principles provide flexible component carrier band-
widths from 1.4 up to 20MHz while 100 RBs are available
for allocation per component carrier in the case of 20MHz
bandwidth. However, the CCS methodology manipulates the
individual component carriers as a single entity and acquires a
total supervision of the channel conditions optimizing system
capacity.
On the other hand, Software Defined Networks (SDN) is
an emerging technology that centralizes the network intelli-
gence enhancing the flexibility of resource manipulation. More
specifically, the network control functions are decoupled from
the data forwarding procedures while the network architecture
becomes easily programmable. Thus, resource optimization is
achieved by dynamically adjusting the traffic forwarding to
meet the changing needs that exist in the modern wireless
communication environment.
In this context, cloud computing could combine both LTE
and SDN technologies advantages to create a novel cloud
assisted Software Defined LTE-A network architecture with
RNs. In this architecture, network control operations are
centrally organized having a wide view of the entire system.
This paper presents the FLS Advanced - Cross Carrier
(FLSA-CC) downlink scheduler which is an enhanced version
of the FLS Advanced (FLSA) presented in [3]. FLSA-CC
operates in a relay assisted LTE-A network which supports
CA. The proposed scheduler aims at a QoS aware resource
allocation, satisfying the requirements of strict real times
services while maintaining an acceptable level of performance
for the best effort service. The performance of FLSA-CC is
studied on a software defined cloud architecture where flow
forwarding and resource scheduling decisions are performed
centrally by a global controller implemented on the cloud. The
2. remainder of the paper is organized as follows. In section 2, the
related research literature is revisited while section 3 describes
the proposed scheduler. Furthermore, section 4 presents the
performance evaluation of the FLSA-CC in comparison with
existing scheduling models and section 5 concludes our work.
II. RELATED WORK
Several downlink packet schedulers have been proposed in
the current literature. This section makes a brief overview of
available scheduling strategies applying to LTE-A systems.
In [4] the authors propose an Iterative Parallel Grouping
Algorithm (IPGA)-based flow scheduler which aims at achiev-
ing service differentiantion while at the same time reducing the
system energy consuption. The algorithm is applied to an SDN
architecture and the scheduling process is performed within
a centralized SDN controller. As follows, a unique priority
value assigned to each routing path is determined in respect of
QoS requirements and OpenFlow switches energy consuption.
Simulation results showed that both priority differentiantion
and energy saving are performed.
The authors in [5] study the performance of the Propotional
Fairness (PF) and Round Robin (RR) non-QoS aware sched-
ulers in relay enhanced LTE-A networks. The PF scheduler
aims at a fair distribution of the network resources to users. Its
metric is estimated using formula (1), where di
k(t) represents
the available throughput for the ith
flow in the kth
RB of the
tth
TTI and ¯Ri
(t − 1) denotes the past average throughput.
Both inband and outband LTE relaying schemes are consid-
ered. More specificaly, in an inband relaying scheme the relay
access link operates in the same frequency with the backhaul
link that connects the RN with the donor eNB (DeNB). On
the contrary, in an outband relaying scheme, the relay access
link operates in a different frequency than the backhaul link
connecting the RN with the DeNB. Simulation results showed
that the PF scheduler achieves better performance that the RR
scheduler in both inband and outband scenarios.
mP F
i,k =
di
k(t)
¯Ri(t − 1)
(1)
In [6] an analysis of the interference phenomenon that
occures in LTE-A networks with type-1 inband RNs is
performed. Also, a Two-Hop Proportional Fairness (2H-PF)
downlink scheduler is introduced. Its metric is estimated using
formula (2), where AL and BH designate the Access Link and
Backhaul Link, respectively. Also, the CR parameter defines
the composite rate estimated by formula (3). The proposed
scheduler is evaluated in scenarios with 1, 2 and 4 RNs per
DeNB while the DeNB activity is deactivated by 0%, 20%
and 40% of the TTI time respectively. Simulation results in
terms of throughput, Signal to Interference & Noise Ratio
(SINR) and Block Error Rate (BLER) showed that the network
performance is quite sensitive when a level of DeNB muting
is applied.
m2H−P F
i,k = max
CR(t)
¯Ri(t − 1)AL
,
CR(t)
¯Ri(t − 1)BH
(2)
CR =
1
(di
k(t))AL
+
1
(di
k(t))BH
(3)
The Modified Largest Weighted Delay First (M-LWDF)
and the Exponential/PF (EXP/PF) QoS aware schedulers are
described in [7] and [8], respectively. Both algorithms extend
the PF metric by taking into consideration network factors
such as delays and packet losses that affect the service quality.
Specifically, the M-LWDF metric is estimated using formula
(4), while the EXP/PF metric is calculated by formula (5).
The DHOL,i parameter represents the head of line delay.
Additionally, the αi value is determined by formula (6), where
δi is the target packet loss ratio and τi is the delay constraint.
Finally, the X value is calculated by formula (7), where Krt is
the number of active real time flows. Numerical results showed
that the M-LWDF scheduler performs better as the network
load is low, while the EXP/PF algorithm gives better results
as the load increases.
mM−LW DF
i,k = ai · DHOL,i · mP F
i,k (4)
m
EXP/P F
i,k = exp(
ai · DHOL,i − X
1 +
√
X
) · mP F
i,k (5)
αi = −
logδi
τi
(6)
X =
1
Krt
·
Krt
i=1
ai · DHOL,i (7)
The LOG RULE and the EXP RULE schedulers presented
in [9] and [10] take into account the head of line packet delay
and the channel quality reported by UEs, to support delay
sensitive flows. Especially, the LOG RULE metric is estimated
using formula (8), where Γi
k is the spectral efficiency for the
ith
user on the kth
subchannel. Correspondingly, the EXP
RULE metric is estimated using formula (9), where bi and
c are configurable parameters. Simulation results showed that
both LOG RULE and EXP RULE could guarantee delay
constraints by configuring scheduler parameters according to
users target delays.
mLOGRULE
i,k = bi · log(c + ai · DHOL,i) · Γi
k (8)
mEXP RULE
i,k = bi·exp(
ai · DHOL,i
c + (1/Krt) j DHOL,j
)·Γi
k (9)
In [11] the authors evaluate the FLS QoS aware downlink
scheduler in an LTE-A topology with RNs. This scheduler
is implemented in two levels. The upper level uses formula
(10) to estimate the ui(x) quota of data that the ith
real
time flow must transmit at the xth
frame to succeed its QoS
constraints. In this formula, qi(x) represents the queue length
in the xth
frame, Mi the number of coefficients used and
ci(n) the nth
coefficient value. Coefficients are used in order
to guarantee the required delay constraints for real time flows.
The target delay τi is determined by formula (11), where Tf
is the frame length. Additionally, the coefficient value ci(n) is
determined by formula (12). Accordingly, the lower level uses
3. the PF metric to allocate network resources to real time flows
for transmitting their quota of data, whereas the remaining
resources are allocated to best effort flows. Simulation results
showed that the FLS scheduler succeeds better performance
for real time flows compared to the PF and LOG RULE
schedulers.
ui(x) = qi(x) +
Mi
n=2
[qi(x − n + 1)
− qi(x − n + 2) − ui(x − n + 1)] · ci(n)
(10)
τi = (Mi + 1) · Tf (11)
ci(n) =
n where 0 ≤ n ≤ 1
ci(n − 1)/2 where n ≥ 2
(12)
III. THE PROPOSED SCHEDULER
This section describes the proposed FLSA-CC scheduler
(Fig. 1) which aims at the optimization of system perfor-
mance using carrier aggregation in the LTE downlink. More
specifically, the FLSA-CC improves the FLSA [3] scheduler
in a cross carrier manner adapting the resource allocation
process at different channel conditions of the aggregated
component carriers. Furthermore, due to the fact that in the
CCS methodology adopted by this scheduler, only the PCC
uses the PDCCH channel for transmission of scheduling
information, interference decrement is observed resulting in
better channel conditions in terms of SINR, increasing thus
the overall system capacity. The FLSA-CC has been built
upon three distinct levels, which cooperate with each other for
dynamically assigning radio resources to users in each TTI.
The upper level of FLSA-CC uses the formula (10) of the
FLS [12] to estimate the ui(x) quota of data that the ith
real
time flow should transmit in each xth
TTI, in order to succeed
its QoS constraints. In other words, ui(x) quota is estimated in
each xth
TTI of a frame, whereas in FLS it is estimated once,
at the beginning of each frame. The FLSA-CC estimates the
coefficient value ci(n) using formula (13), where N represents
the number of component carriers. Performance improvement
has been observed due to the fact that in FLS, when a real time
flow transmits its ui(x) quota of data, it loses the opportunity
to continue the transmission until the beginning of the next
frame. By recalculating the formula (10) in each TTI (instead
of estimating it only at the beginning of each frame), the
FLSA-CC provides more resources to real time flows that have
remaining data for transmission.
ci(n) =
n where 0 ≤ n ≤ 1
ci(n − 1)/(2 · N) where n ≥ 2
(13)
In each TTI, the middle level uses a cross carrier version
of the MLWDF scheduler, called MLWDF-CC, to allocate
RBs to real time flows for transmitting their ui(x) quota of
data obtained from the upper level. This scheduler extends
the PF-CC metric [13] [14] mP F −CC
i,k given in formula (14).
Accordingly, the MLWDF-CC metric is evaluated by formula
Fig. 1. The FLSA-CC scheduler design
(15) where the αi value is determined by formula (6). As
follows, the use of the cross carrier QoS aware MLWDF-CC
scheduler realizes improved resource distribution among the
real time flows in comparison with the FLS scheduler which
at the second level uses the non-cross carrier principle as well
as the non-QoS aware PF algorithm.
The third level has been added to allocate the remaining
RBs of each TTI to best effort flows using formula (14) of
the PF-CC algorithm.
mP F −CC
i,k =
di
k(t)
N
j=1
¯Ri,j(t − 1)
(14)
mMLW DF −CC
i,k = ai · DHOL,i · mP F −CC
i,k (15)
IV. SIMULATION ENVIRONMENT
The simulation environment is implemented using an ex-
tended version of the Lte-Sim [15] simulator. More specif-
ically, the iCanCloud [16] and the OpenFlow [17] modules
of the Omnet++ [18] simulator have been configured and
embedded to the Lte-Sim enabling the ability to include
cloud infrastructure and SDN controllers to the simulated LTE
topologies.
The simulation environment consists of an LTE Evolved
UMTS Terrestrial Radio Access Network (E-UTRAN) and a
Cloud infrastructure. The E-UTRAN includes 7 DeNBs and
28 RNs (4 per DeNB). The transmission radius is equal to
1 kilometer for each DeNB and 100 meters for each RN
respectively. Also, each RN is positioned at 90% of the
transmission radius of its DeNB. Furthermore, Type-1 Outband
Relaying is applied where two link types are defined, the
access link and the backhaul link. The access link is used
for communication between a UE and an RN or a DeNB
using a frequency f1, while the backhaul link is used for
communication between an RN and a DeNB using a frequency
f2 = f1.
Inter-band CA is applied in each DeNB and RN. According
to this CA configuration, two component carriers, which
4. belong to different frequency bands, are aggregated. Each
component carrier bandwidth is equal to 20MHz and contains
100 resource blocks. Thus, 40MHz bandwidth is assigned to
each cell (RN or DeNB) and 200 RBs are totally available
for scheduling in each TTI. Table 1 presents the system sub-
frequencies assigned to each cell.
TABLE I
THE SUB-FREQUENCIES THAT ASSIGNED TO EACH CELL
Cell Aggregated Component Carriers
DeNB0
PCC: 1805 MHz − 1825 MHz (band 3)
SCC: 760 MHz − 780 MHz (band 28)
DeNB1,3,5
PCC: 1825 MHz − 1845 MHz (band 3)
SCC: 870 MHz − 890 MHz (band 5)
DeNB2,4,6
PCC: 2110 MHz − 2130 MHz (band 1)
SCC: 940 MHz − 960 MHz (band 8)
Relay nodes
Case 1
PCC: 2620 MHz − 2640 MHz (band 7)
SCC: 780 MHz − 800 MHz (band 28)
Case 2
PCC: 2640 MHz − 2660 MHz (band 7)
SCC: 800 MHz − 820 MHz (band 20)
The 3GPP urban channel model [19] [20] is considered.
Due to the assumption that the channel between DeNB or RN
and UE encounters non-line-of-sight (NLOS) transmission, its
propagation loss is estimated using formula (16) and (17),
respectively, where d represents the distance among the nodes
and fc the carrier frequency. Correspondingly, due to the
assumption that the channel between a DeNB and an RN
encounters line-of-sight (LOS) transmission, its propagation
loss is estimated using formula (18).
PLNLOS
DeNB→UE = 37.6·log10(d)+58.94+21·log10(fc) (16)
PLNLOS
RN→UE = 36.7 · log10(d) + 22.7 + 26 · log10(fc) (17)
PLLOS
DeNB→RN = 22 · log10(d) + 28 + 20 · log10(fc) (18)
The Cloud contains a set of virtual machines (VMs) and
implements the functionalities of the LTE Evolved Packet Core
(EPC). Additional VMs with user applications are created.
Specifically, one VM is created for each UE running three
applications namely one VoIP, one video and one best effort.
Flow forwarding as well as resource scheduling in each
DeNB and RN are performed using a centralized global
controller placed into the SGW having a wide view of the
entire system. The simulated topology is presented in figure
2.
V. PERFORMANCE EVALUATION
The performance of the FLSA-CC was evaluated against the
PF, MLWDF, EXP/PF, FLS, FLSA, EXP-RULE and LOG-
RULE schedulers. Especially for the EXP-RULE metric the
used parameter set is ai ∈ [5/(0.99 · τi), 10/(0.99 · τi)], bi =
1/E[Γi
] and c = 1 as proposed in [10] for best performance.
Table II summarizes the factors considered by each scheduler
for resource allocation, demonstrating that the FLSA-CC is
the most complete strategy. Furthermore, the full band periodic
Channel Quality Indication (CQI) reporting scheme is applied.
Thus each UE reports its downlink SINR to RN, for each
Fig. 2. The simulated topology
component carrier in every TTI. The RN quantizes the reported
SINR value and calculates the CQI as described in [15]. Then,
it uses the CQI to guarantee a maximum BLER less than 10%
regardless of the scheduling strategy applied.
TABLE II
THE PARAMETERS CONSIDERED IN EACH SCHEDULER
Scheduler SINR Throughput
HOL
Delay
Max.
Delay
Max.
PLR
Queue
Length
CCS
PF
MLWDF
EXP/PF
FLS
FLSA
FLSA-CC
EXP RULE
LOG RULE
A number of users, move inside the borders of each RN
according to the random way-point mobility model. Each user
receives two real time flows, an H264 video with bitrate equal
to 440 kbps and a Voice over IP (VoIP) using the G.729 codec.
Furthermore, one best effort flow is added as background
traffic. Table III summarizes the simulation parameters.
A. Real time services results
Due to the fact that the simulation environment inlcudes an
LTE topology with RNs, a two hop target delay for real time
flows τi = τi,DeNB→RN + τi,RN→UE is considered, where
τi,DeNB→RN represents the target delay between a DeNB and
an RN, the τi,RN→UE represents the target delay between an
RN and a UE. Also we consider τi,DeNB→RN = τi,RN→UE.
In general, QoS aware schedulers increase the packet loss
ratio (PLR) to maintain the required τi. This strategy is based
5. TABLE III
THE SIMULATION PARAMETERS
Parameter Value
Simulation time 100 seconds
Downlink bandwidth 2*20 = 40 MHz
Modulation QPSK, QAM-16 and QAM-64
DeNBs number / radius 7 / 1 km
Relay nodes number / radius 4 per DeNB / 100 m
Number of users up to 100 users per relay node
Users mobility Random way point
Traffic models
Real time:
H264 video at 440 kbps
VoIP using G.729 codec
Best effort: Web
Fig. 3. Real time flows packet loss ratio using different target delays
on the assumption that real time services such as VoIP and
Video can not make use of expired packets. Thus, since the
delay constraint is satisfied, the algorithms are evaluated in
terms of PLR, so as to have a comprehensive view about the
performance improvements. Figure 3 illustrates the impact of
the target delay parameter τi in the PLR for VoIP and video
flows, respectively, for the case of having 100 users per RN.
While the target delay increases from 50ms to 150ms, the
PLR decreases. Additionally it may be observed that FLSA-
CC compared with FLSA exhibits lower PLR independed of
the target delay parameter.
In figure 4, the PLR for VOIP and video flows is presented
while the number of cell RN users varies from 20 to 100. In
this case, the considered target delays are set to 100ms and
150ms for VoIP and video flows respectively, as determined
by the LTE QoS class specifications for these service types.
As shown, FLSA-CC results in a lower PLR than the rest of
the algorithms. Specifically, FLSA shows a marginal decrease
of its PLR for VoIP flows as well as up to 3% lower PLR for
video flows compared to FLSA.
The analysis of the throughput offered to real time services
provides an important insight on the performance of the FLSA-
CC in comparison with the other schedulers. As presented in
figure 5 the FLSA-CC outperforms the rest of the schedulers,
independently of the number of users for VoIP and video flows.
This is expected due to the cross carrier scheduling operating
principle applied as well as due to the recalculation of formula
(10) in each TTI by the upper level of the FLSA-CC. More
specifically, the FLSA-CC succeeds higher throughputs than
the rest of the algorithms providing rates of up to 800kbps for
Fig. 4. Real time flows packet loss ratio
Fig. 5. Real time flows throughput
VoIP and up to 28Mbps for video services.
The proposed scheduler is also evaluated in terms of Jain
fairness index, which is estimated using formula (19) where
n is the number of the service flows and xi is the throughput
of the ith
flow.
Jain Fairness =
(
n
i=1 xi)2
n ·
n
i=1 x2
i
(19)
Flows with the same service constraints must receive similar
QoS to avoid the situation of having satisfied users against
dissatisfied ones of the same service type. The maximum value
of fairness is 1 while the more a scheduler accomplishes a
value close to 1, the more the resource allocation is fair.
Figure 6 demonstrates that the FLSA-CC scheduler improves
the fairness for both VoIP and video flows.
Fig. 6. Real time flows fairness index
6. Fig. 7. Best effort flows throughput and fairness index
B. Best effort services results
In this subsection FLSA-CC, FLSA and FLS which accom-
plish better performance for real time services are evaluated
for best effort flows in terms of throughput and fairness index.
As presented in figure 7, the FLSA-CC outperforms the other
two schedulers and provides throughput up to 1.5Mbps for
best effort flows even when the number of users increases,
while the FLSA accomplishes only a 100kbps throughput.
Additionally, the FLSA-CC scheduler significantly improves
the fairness index of best effort flows.
VI. CONCLUSION
In this work FLSA-CC QoS aware cross carrier downlink
scheduler is proposed as an extended version of the FLSA [3].
FLSA-CC operates in an LTE-A network with relay nodes in
a CA mode. The proposed scheduler has been built upon three
distinct levels which cooperate with each other to allocate the
network resources to users in a manner that the requirements
of strict real times services are satisfied while starvation of
best effort traffic is avoided. The performance of FLSA-CC is
compared against other scheduling algorithms in terms of PLR,
throughput and fairness index, in a cloud assisted software
defined architecture. Simulation results showed that the FLSA-
CC scheduler outperforms the rest of the scheduling schemes
by achieving better resource allocation for both real time and
best effort services..
ACKNOWLEDGEMENT
The publication of this paper has been partly supported by
the University of Piraeus Research Center (UPRC) and the
Technological Educational Institute of Western Macedonia.
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