Joint MMSE designs for analog network coding and different MIMO relaying schemes: A unified approach and performance benchmarks.

To gain understanding of the analog network coding and different MIMO relaying schemes and to facilitate the scheme selection, there is a need for a unified approach and performance benchmarks. In this paper, analog network coding, direct transmission, Two-Hop relaying, and cooperative relaying schemes are analyzed and compared. A unified approach, the novel generalized iterative approach, is proposed for jointly designing the MMSE MIMO processors (including precoders, relay processors and decoders) for these schemes. Numerical results show that for each scheme, there exist system and channel parameter regime(s) where it is the most desirable among the four schemes. Performance benchmarks, physical insights and some guidelines for MIMO relaying scheme selection are presented.