Asymptotic Capacity and Optimal Precoding in MIMO Multi-Hop Relay Networks

A multi-hop relaying system is analyzed where data sent by a multi-antenna source is relayed by successive multi-antenna relays until it reaches a multi-antenna destination. Assuming correlated fading at each hop, each relay receives a faded version of the signal from the previous level, performs linear precoding and retransmits it to the next level. Using free probability theory and assuming that the noise power at relaying levels— but not at destination— is negligible, the closed-form expression of the asymptotic instantaneous end-to-end mutual information is derived as the number of antennas at all levels grows large. The so-obtained deterministic expression is independent from the channel realizations while depending only on channel statistics. Moreover, it also serves as the asymptotic value of the average end-to-end mutual information. The optimal singular vectors of the precoding matrices that maximize the average mutual information with finite number of antennas at all le...

• Type: Journal
• Year: 2011
• Where: TIT
• Authors: Nadia Fawaz, Keyvan Zarifi, Mérouane Debbah, David Gesbert
• Keywords: End-to-end Mutual Information, Precoding Singular Vectors, Singular Vectors, TIT 2011