Virtual Mimo System Cooperation Relay Mechanism

MIMO technique can enhance the capacity of communication system. Virtual MIMO technique has been proposed because of the difficulty of multi-antenna deployment on mobile terminal while it is becoming more and more portable. Terminals with single antenna cooperate with each other to form Virtual Antenna Arrays, transmitting with multi-hop relay. This paper focuses on cooperative relay of Virtual MIMO system. Our contributions are listed as bellows.Firstly, this dissertation proposes a new cooperative relay mechanism based on double mode, decomposes cooperative relay mechanism into two stages: VAA inter-cells communication and VAA intra-cell communication using different techniques. Translate the first stage of cooperative diversity into VAA inter-cells communication in one technique and translate the second stage of cooperative diversity into VAA intra-cell communication in another technique based on the research of cooperative diversity. Compared to tradition cooperative relay using only one mode, under our new mechanism VAA inter-cells communication and VAA intra-cell communication can work at the same time seperately. As a result, we can design inter-cells clustering algorithm and intra-cell routing algorithm seperately,, so the protocols of cooperative relay mechanism is simplified and the delay is shorted. According to the characteristics of VAA inter-cells and intra-cell communication, proposes a cooperative relay mechanism based on WPAN/WLAN techniques.Secondly, this dissertation proposes a clustering algorithm suitable for VAA inter-cells clustering, which called RDLN clustering algorithm on the base of WSN's clustering algorithm. Analyses and simulates the survival terminals ratio of the network and performance Evaluation, Proposes system capacity coefficient, analyses and simulates factors affecting the system capacity coefficient, such as the number energy rank, the network size, clustering radius, the maximal numbers in one VAA cell, the maximal distance between clustering heads.Thirdly, this dissertation also proposes specific relay mechanism. Analyses and simulates the performance repeat-code, STBC random code, STBC code, proposes a way to apply distributed STBC to our novel cooperative relay mechanism. Analyses,simulates and compares the performance of system delay under our novel cooperative relay mechanism and the performance of traditional cooperative relay mechanism,Finally, this dissertation studys other techniques that can enhance the performance of cooperative relay, such as terminal selection, Power allocation; proposes the possible method of their application.