Cooperative Transmission with Decode-and-Forward MIMO Relaying in Multiuser Relay Networks

This paper considers multiple-input/multiple-output(MIMO) cooperative communication systems with a decode-and-forward (DF) relay. We propose novel rate maximization schemes which utilizes uniform channel decompositions (UCD)to decompose the MIMO channel between a base station (BS) and a relay station (RS). In the proposed scheme, the MIMO channel is decomposed into multiple independent subchannels with equal gains by the UCD and the power allocation will be performed over the subchannels to maximize achievable throughput. We consider not only a simple individual power constraint but also a sum power constraint as well which is useful for the DF based relay systems. It will be shown through simulations that proposed schemes enhance the achievable throughput significantly by distributing the transmit power of the BS and the RS efficiently.