Research On Uplink Scheduling And Resource Management For VoIP Over Mobile WiMAX

Mobile WiMAX is a promising broadband wireless technology. In recent years VoIP has emerged as one of the promising applications on the Internet with rapidly development of various VoIP CODECs technologies, both Mobile WiMAX and VoIP they share One key benefit of great cost savings due to lower deployment, implementation, maintenance and up gradation cost. Therefore, VoIP over Mobile WiMAX will play a critic role in the deployment of Mobile WiMAX networks. But, the uplink scheduling and resource management remain as a major problem that may seriously impact the deployment of VoIP over Mobile WiMAX. The uplink Scheduling and Resource Management refers to operation of serving BS (Base Station) MAC layer to effectively manage the transmission of allocable resources, which covers Scheduling Services, power saving, Handover etc., to achieve optimal resource utilization and enhanced system performance. Regarding the VoIP services the IEEE 802.16e specifications only defines the MAC layer functions modules of uplink Scheduling and Resource Management, as well as the basic content and implementation rules of these modules, but does not specifically propose any feasible schemes or implementing algorithms. Therefore, in this thesis we have concentrated our efforts on enhancing the uplink scheduling and resource management performance of the most common used VoIP CODECs over Mobile WiMAX. This thesis gives an overview of the IEEE 802.16e Mobile WiMAX standard as well as the VoIP CODECs technologies. Through this introduction we address the main challenges that affect the VoIP CODECs over Mobile WiMAX transmission. The main purposes of this thesis could be summarizes as follows:1. We designed a novel comprehensive dynamic uplink scheduling proposal (CDUSP) for all major VoIP CODECs over Mobile WiMAX. Through investigating the standard defined three conventional uplink scheduling service algorithms as well as the most common used VoIP CODECs. The CODECs have been classified into two main categories based on their characteristics and it's silence compression performance, several novel uplink scheduling algorithms are proposed. Furthermore, our designed (CDUSP) proposal with proper modification to the uplink scheduling framework structure and procedure is planned, the CDUSP is significantly capable of dynamically integrate and manage all our proposed uplink scheduling algorithms within the Mobile WiMAX QoS scheduling framework. Besides, it greatly optimizes the Mobile WiMAX for efficiently support the VoIP CODECs uplink transmission. Through the simulation results and numerical validations, all proposed algorithms performs efficiently than the conventional algorithms over enhancement of resource utilization, total throughput, and reduction of packet transmission delay.2. Thirdly, the coexisting of multiple VoIP users resource management enhancement is investigated, through proposing different scheduling algorithms with applying multiple of our novel several grant interval schemes, to different preconfigured classified categories based on capturing several factors, based on these different factors the users classification and corresponding resource allocation schemes will be different, performance comparisons between the conventional algorithms and the proposed algorithm is given. Further, simulation result and numerical validations has proved the efficiency of the proposed algorithm over enhancement of resource utilization, total throughput, increment of system capacity, and number of voice users supported.3. Through investigating and analyzing the three power saving classes defined by 806.16e standard , we propose a new two improved power saving algorithm that greatly suitable for different VoIP CODECs with silence compression, the first algorithm is interval-flexible PSCII power saving algorithm that utilize the exponential increment scheme during the mutual silence period , this algorithm is suitable to the long frame duration , the second algorithm is called multiple termination schemes power saving algorithm , this algorithm through integrating both power saving calass (PSC) I and PSCII ,with concern to the PSCI two different mechanisms of sleep mode activation . Our proposed algorithm basically follows PSCII during talk-spurt periods, but uses the two different wake up schemes of of PSCI during silent periods. The analysis and simulation results show that our proposal reduces power consumption effectively during silent periods while satisfying the maximum allowable end-to-end delay and low packet drop probability constraints with respect to the QoS of VoIP.