Advanced designs in wireless communication systems

Abstract

In this thesis, we examine the designs and performance of existing and next-generation wireless communication systems. Firstly, we propose a frame dispatching algorithm for the parallel wireless links system in which a client can connect to multiple access points simultaneously. The algorithm determines which link should be used for the frame transmission. Simulation results show that using this algorithm in the system can give better QoS and higher throughput Secondly, we design a transcoding proxy which adopting both prefetching and transcoding functions in wireless communication systems. In our study, the relationship between transcoding speed and system bandwidth is formulated. By applying this formula to the system, a lower average system cost, smaller user experienced latency and higher system throughput can be achieved. Thirdly, a deterministic prefetching scheme is proposed for mobile communication systems. There are two main components in the scheme: User Profile Database (UPD) and Intelligent Proxy Server (IPS) which decide when and what objects are prefetched for the user. It is found that the mean user request delay can be significantly reduced while lower link utilization can be obtained by using this scheme. Lastly, we analyses the challenges in migrating from existing systems to the next generation ones. These challenges are grouped into three main aspects: system, user, and service. In this thesis, each challenge is discussed in details with possible solutions provided.