| Summary: | 博士 === 國立交通大學 === 電子研究所 === 99 === In this dissertation, we investigate the problem of scheduling and resource allocation in wireless cellular systems. We propose a new physical indicator which can be considered in the scheduling metrics function to further improve scheduling performance. The new physical indicator is named by “self-opportunity,” which means the chance of benefit from users’ point of view. The propose self-opportunity introduces a new dimension to scheduling metrics function and it can cooperate with conventional scheduling algorithms. We will show that the concept of self-opportunity can help the scheduler improve transmission performance, especially for scheduling real-time applications. To identify the performance improvement, a system-level simulator is established to evaluate the scheduling performance of each algorithm.
In addition, we investigate a special case of scheduling H.264/AVC scalable video coding (SVC) based traffic. Due to the layered characteristic of SVC traffic, we propose a cross-layer system architecture to adapt the traffic amount of SVC video streaming according to the transmission bandwidth of last-mile wireless environment. Besides, we use “importance-based intra-service packet scheduling” to further improve the transmission performance and QoS of the SVC-encoded traffic. Importance-based intra-service packet scheduling can be applied if the arriving SDUs of a service flow can be categorized to multiple levels of importance, which is the main characteristic of SVC-encoded traffic. Simulation results and subject test show that the proposed system architecture can provide better performance for SVC-encoded traffic.
Furthermore, we propose an analytical model to evaluate the system throughput and user capacity of a wireless cellular system. The analytical model contains two components including the MCS distribution model and resource allocation model. The analytical model is derived based on the resource allocation behavior and the constraint of limited wireless resources. Besides, we also use an example of two-hop relay networks to demonstrate how to use the analytical model. The proposed analytical model can provide the engineering sense for the system deployment.
|
|---|
