Research On Joint Network-Channel Coded Cooperative Scheme

The fading of radio channels is one of the key factors that affect the performanceof wireless communication system. Cooperative communication technique is aneffective method to combat against channel fading. The technique makes it possiblefor single-antenna terminals to share their antennas to construct a virtualmulti-antenna array, so that the terminals can also attain spatial diversity gain.Separate network-channel coded cooperative scheme, in which network coding andchannel coding are used separately in network layer and physical layer, can improvethroughput of cooperative system. However, network coding and channel coding isdesigned jointly in joint network-channel coded cooperative scheme. Compared toseparate network-channel coded cooperative scheme, it can further improve theperformance of the cooperative system because of coded gain.This thesis focuses on the design of cooperative scheme, which combinesnetwork coding and channel coding. For two-user multiple-access relay channelsystems, a joint network-channel coded cooperative scheme combining double-binaryTurbo code and network coding is researched. In this scheme, the received bits fromtwo users are decoded and encoded by double-binary Turbo code at the relay node,and only the check bits are sent to the destination node. The destination node utilizesthese check bits and received information from two users to decode jointly. Comparedto separate network-channel cooperative scheme, simulation results show that thescheme can improve the performance of the cooperative system in Rayleigh channels.Furthermore, in order to expand the range of application scenarios, anetwork-channel coded scheme, based on maximal-ratio combining in logarithmiclikelihood ratio domain, is researched for multiple-source multiple-access relaychannel system. In this scheme, before channel decoding, the received bits inlogarithmic-likelihood-ratio domain are processed by maximal-ratio combining.Different network decoders are choose according to the output of channel decoders.Compared to separate network-channel cooperative scheme, simulation results showthat the scheme can improve the performance of cooperative system.