Approximate Gaussian Density Evolution Based Analysis of Distributed and Adaptive Turbo Codes

In this paper, the non-selective Decode-and-Forward (DF) scheme proposed in is analyzed using approximate Gaussian density evolution (DE). Based on the DE analysis, performance is shown to be improved by adaptively changing the transmit code at the relay node in response to the channel conditions. Simulation results show that the proposed adaptive scheme improves performance, particularly when the relay is closer to the destination than to the source. In addition, the adaptive scheme does not increase network overhead.