Optimized low density parity check codes designs for half duplex relay channels

We propose in this paper optimized designs for LDPC codes which are able to work close to the theoretical bounds for the half duplex relay channel using the decode and forward strategy originally proposed by Cover and El Gamal. The challenge is that we have to find two codes operating at different rates and at different SNR´s: one for source-destination and the other for relay-destination transmission. We use density evolution together with Gaussian approximation for the design of the proposed irregular LDPC codes. Simulation results show that our proposed LDPC enable to work within less than 1.0 dB from the theoretical limit capacities under different channel conditions.