Researches On Cross-Layer Optimization In Wireless Communication Systems

Techonology changes the style of life and the needs of life impel the technology. The requirment to communicate freely and satisfactorily challenge the wireless telecommunication more and more. The diversity of user's requirement, the variety of wireless channel and the dynamic of the network topology make the traditional layered network disign become unresonalbe. This design cannot utilize the frequence resource effectively, ignore the fuzzy information when process the multimedia data and cannot coordinate multiple QoS parameter in different layer. These faults make the different design concept neccessary and important. This paper focused on cross-layer design and researched the improved wireless TCP, cross-layer QoS management architecture, the improved algorithm to to improve performance of TCP Over IEEE 802.11 DCF and A cross-layer scheme to make effectiveness and fairness tradeoff for TCP in W-CDMA/UMTS, the main work include:The optimal value of the TCP data sending rate is researched when the wireless channel is in bad state, according to this value two algorithms to adjust the size of TCP C WND are presented. The target of most research about TCP in wireless network is to improve the throughput, so the size of C WND dose not decrease if the packet loss is due to the corruption, which results in the decrease of the reliability of TCP when the heavy packet loss rate occurs. Our scheme considered the requirement of throughput and reliability at the same time. We use simulation results to demonstrate that the QoS requirement is met and the throughput is not decline clearly.Providing quality-of-service(QoS) to multimedia delivery in wireless networks has attracted intensive research, we investigate this problem and present a new QoS management architecture based on cross-layer intercommunion. This architecture consists of source rate constraint,...