Design and optimization of joint network-channel LDPC code for wireless cooperative communications

In this paper, we develop a joint design method of network-channel Low Density Parity Check codes (LDPC) codes by constructing joint network-channel parity check matrix. Random network coding is performed to provide side information for both the Source and Relay' s transmission. This system matrix makes an easy way to collect all independent signal copies to provide a spatial diversity gain. And the complexity of network coding is linear to the block length ∼O(n). Then, the optimization of joint network-channel LDPC code is conducted in term of maximizing the system rate. Based on the joint network-channel LDPC codes, we presents a protocol for wireless cooperative communications, which is very effective to combat the channel fading without much rise in system bandwidth and transmitting power. A traditional three-node model is built to describe the protocol where relay not only helps source to transmit but also has its own information to transmit.