Randomized Distributed MIMO with Limited Feedback in Dynamic Relay Networks

In this paper, a cooperative spatial multiplexing scheme is considered for dynamic relay networks. We assume that each relay node is equipped with a single antenna. To obtain spatial multiplexing gains, the distributed multiple-input multiple-output (MIMO) scheme, in which cooperating nodes act as elements of a multi antenna system, has been proposed in many papers. Since the nodes need to know their specific stream and pilot index, either internode communication or a central control unit is required. Our design objective is to obtain spatial multiplexing gains while eliminating the need for stream and pilot allocation. We introduce a novel randomized strategy that decentralize the transmission of multi streams from a set of distributed relay nodes. We analyze the constraints on the random scheme, and propose a limited feedback scheme to further improve its performance.