Information rates and coding for wireless MIMO relay channels

In this paper, we design turbo-based coding/decoding schemes for relay systems with multiple transmit/receive antennas at the respective terminals. In the proposed scheme, the source node sends coded information bits to both the relay and the destination nodes, while the relay forwards simultaneously its estimate for the previous coded block to the destination after decoding and re-encoding. Then, the destination observes a superposition of the codewords and uses an iterative decoding algorithm to estimate the transmitted messages. We also provide the capacity bounds and information rate bounds with binary inputs. It is shown that the performance is typically about 1.0-1.5 dB away from the theoretical limits, and a remarkable advantage can be achieved over the direct and multihop transmission schemes.