Joint Design Of Physical Layer Network Coding And Channel Coding

On the basis of Information Theory, R.Ahlswede and some researchers put forward the conception of network coding in 2000, which could highly improve the throughput of the network in order to transmit more information with the limited network resource. In Two- way relay channel, the transmission efficiency of the relay node can be improved effectively without loss of diversity gain via the network coding. In order to improce the BER performance of the relay network, joint network coding and channel coding can be used in the relay node, which has been received much attention during the past few years.There are many traditional processing methods such as amplify and forward (AF), decode and forward (DF), coded cooperation (CC). Later researches combine these methods and propose some typical coding strategies such as joint design of channel coding and physical layer network coding. Then the encoding and decoding principles of Turbo codes and LDPC codes are dicussed focusing on the decoding algorithm. The performance of Turbo codes and LDPC codes in different bit rate and code length are compared by simulation. After that, we choose LDPC codes used in joint channel coding and network coding method.On the design of LDPC codes under relay channels, we construct the new scheme named generalized joint channel physical network coding (G-JCNC) in two-way relay channels. In G-JCNC, a virtual LDPC encoder is constructed in order to find the optimum LDPC code that matches LDPC codes at the sources. After a detailed introduction of decoding process, a new decoding algorithm is derived. Comparing with the scheme called a simple joint channel and physical network coding scheme (S-JCNC) simulation results show that G-JCNC based on joint channel coding and network coding has better performance than S-JCNC.