The Application Of Network Coding In The Cooperative Relay System

Network coding can improve the capacity and reliability of a communication system. Multiple input multiple output (MIMO) technique can overcome the limitations of multi-path fading effectively in radio channels, and therefore holds the potential to drastically improve the capacity and reliability in future wireless communication system. However, it is difficult for a wireless terminal, which is limited by size, cost and hardware complexity, to support multiple antennas. Recently, the cooperative diversity technique, which is based on user cooperation and relay cooperation etc, has emerged as a promising technique. The essence of this technique lies in that single-antenna terminals in a multi-user scenario are allowed to share their antennas and other resources through distributed transmission and processing so that a virtual multi-antenna transmitter is achieved, and hence reap the spatial diversity benefits of the virtual MIMO system, This paper, employing the advantages of the network coding technique and the MIMO technique, proposes a network coding diversity scheme based on the phase plus, and its theoretical analysis as well as simulation results. The main contribution of this paper will be summarized as follows:At first, based on the feature of multi-phase shift keying (MPSK) modulation, this paper gives a new network coding scheme in Bi-direction relay channel model. Simulation results shows that:comparing with the traditional relaying protocol and direct protocol, the proposed relaying protocol can improve the performance significantly under the condition of the system having a same power utilization, And then, this paper also simulated the power allocation, and figure out the best region for the power allocation coefficient. And last, the simulation result verifies that:if the two signals make different multi-phase shift keying (MPSK) modulations the proposed scheme can solve this problem well.In both the Bi-direction relay channel and Multi-access relay channel models, the relay node should deal with the data which comes from different users. In order to solve the problem that the relay received non-equal length signals from different users, The paper proposal a proposed superimposed XOR scheme in both Bi-direction relay channel scenario and Multi-access relay channel scenario This literature derives the rate region and the Maximum sum-rates(MSRs) of the both aforementioned relay strategies. Simulation result shows that:weather in different relay strategies, or in different time control protocols, the proposed scheme can always achieve the largest sum-rates among all the considered physical layer network coding (PLNC) schemes, and also can obtain the best achievable rate region.