Relay-Assisted Spatial Multiplexing in Wireless Fixed Relay Networks.

Abstract

Fixed relays are expected to be a part of future infrastructure-based wireless networks. Besides coverage exten- sion, such relays can form advanced architectures due to the flexibility in their power expenditure and physical size. This paper explores the potential benefits of multi-antenna relays for spatial multiplexing of independent data sources sending data to a common multi-antenna destination such as a base station or an access point. Overall, the system resembles a horizontally coded layered space-time architecture. In particular, we consider zero forcing decision feedback (ZF- DF) type MIMO receivers and study their outage performance under various (non-selective and selective) digital relaying pro- tocols. For diversity relaying protocol, we propose two schemes, Joint ZF-DF and Parallel ZF-DF, for joint processing (combining and decoding) of the direct user signals and the signal from the relay. We show that with the proposed selective diversity relaying protocols and joint ZF-DF processing, the outage probability of the system can be decreased significantly.