Performance analysis of packet scheduling algorithms for long term evolution (LTE)

University of Technology, Sydney. Faculty of Engineering and Information Technology.The third generation partnership project long term evolution (3GPP LTE) system is proposed as a new radio access technology in order to support high-speed data and multimedia traffic. The 3GPP LTE system has a flat radio access network architecture consisting of only one node, known as eNodeB, between user and core network. All radio resource management (RRM) functions are performed at the eNodeB. As one of the essential RRM functions, packet scheduling is responsible for the intelligent allocation of radio resources for active users. Since there is a diversity of the traffic types in wireless systems, active users may have different Quality of Service (QoS) requirements. In order to satisfy various QoS requirements and efficiently utilize the radio resources, a packet scheduler adopts a specific packet scheduling algorithm when making decisions. Several packet scheduling algorithms have been proposed in the literature. The objective of this thesis is to evaluate the performance of the well-known and some recently proposed packet scheduljng algorithms and identify the suitability of these algorithms in the downlink LTE system. The perfonnance evaluation of packet scheduling algorithms based on both computer simulation and theoretical analysis is provided in this thesis. The performance of packet scheduling algorithms is evaluated in three scenarios including 100% RT scenario, 100% NRT scenario and 50% RT and 50% NRT scenario under the downlink LTE simulation environment. The simulation results for wellknown packet scheduling algorithms show that Maximum-Largest Weighted Delay First (M-LWDF) outperforms other algorithms in the 100% RT scenario, while Exponential/Proportional Fair (EXP/PF) is comparatively more suitable in the 50% RT and 50% NRT scenario. In the 100% NRT scenario, Proportional Fair (PF) and Maximum Rate (Max-Rate) achieve a good throughput and resource block (RB) utilization performance while Round Robin (RR) has the best fairness performance. Additionally, two recently proposed algorithms are evaluated and can be considered as the packet scheduling candidates. The simulation results show that Sun Qiaoyun' s Algorithm is more appropriate than Jeongsik Park's Algorithm for the downlink LTE supporting the real-time traffic. The mathematical model for performance evaluation of the packet scheduling algorithms in the downlink L TE system is discussed in this thesis. The theoretical delay analysis for OFDMA system and the theoretical throughput analysis of PF algorithm is studied and validated in detail. This thesis moves further to theoretical performance analysis of M-L WDF and obtains the analytical result of the expected throughput of M- WDF

Cross-layer scheduling and resource allocation for heterogeneous traffic in 3G LTE

3G long term evolution (LTE) introduces stringent needs in order to provide different kinds of traffic with Quality of Service (QoS) characteristics. The major problem with this nature of LTE is that it does not have any paradigm scheduling algorithm that will ideally control the assignment of resources which in turn will improve the user satisfaction. This has become an open subject and different scheduling algorithms have been proposed which are quite challenging and complex. To address this issue, in this paper, we investigate how our proposed algorithm improves the user satisfaction for heterogeneous traffic, that is, best-effort traffic such as file transfer protocol (FTP) and real-time traffic such as voice over internet protocol (VoIP). Our proposed algorithm is formulated using the cross-layer technique. The goal of our proposed algorithm is to maximize the expected total user satisfaction (total-utility) under different constraints. We compared our proposed algorithm with proportional fair (PF), exponential proportional fair (EXP-PF), and U-delay. Using simulations, our proposed algorithm improved the performance of real-time traffic based on throughput, VoIP delay, and VoIP packet loss ratio metrics while PF improved the performance of best-effort traffic based on FTP traffic received, FTP packet loss ratio, and FTP throughput metrics