Trellis Combining Approach for Demodulate and Forward Based Multiple Access Relay Channels
AbstractNetwork coding has emerged as a paradigm for communication systems in which each intermediate node in the network generates and transmits output data by encoding previously received packets in a manner to increase the bandwidth efficiency of the system. The multiple access relay channel (MARC) is one of the real-world reference network coded communication scenarios where multiple users transmit data to a common destination through the use of one or multiple relays. In this paper, performance of demodulate and forward protocol which is among the prominent digital relaying techniques is considered in MARC systems. A convolutional code is used as the channel code. Maximum likelihood (ML) detection and user selective relaying are utilized in order to decrease the performance degradation due to decision errors at the relay. The simulation results obtained for Rayleigh fading channels have shown that the examined joint channel-network coding approach is superior with respect to non-cooperative system by providing full diversity gain.