Coded Cooperation for Ad Hoc Networks with Spatial Multiplexing

In this paper we design a network based on cooperative spatial multiplexing (SM), capable to adaptively support terminals with multiple antennas and multiple cooperating nodes. Our proposal overcomes limitations of existing cooperative networks based on space-time block codes (STBC), i.e., their need for symbol synchronization and signalling overhead for cooperation setup. Furthermore, the presented cooperation scheme is designed with the aim of improving the overall network performance, while most of the proposals in the literature focus on single link performance. SM is integrated with decision- feedback multiuser receivers for both the non-cooperative and the cooperative phases in order to maximize the use of radio resources. The cooperation efficiency is further enhanced by using a hybrid automatic repeat request (ARQ) mechanism for error control, implemented with linear erasure packet codes. Also in this case, the packet-based coding allows to have no signalling overhead for cooperation. Extensive results are provided, obtained by simulation of the complete PHY and MAC layers for a realistic network scenario with several nodes.