Capacity gain from receiver cooperation for MIMO broadcast channels

While channel state information (CSI) at the transmitter is critical to the system capacity of multiple input multiple output (MIMO) broadcast channels, its acquisition is practically intricate. This paper offers an alternative and investigates a special MIMO broadcast channel, which exploits the benefit of receiver cooperation and renders it unnecessary to acquire CSI at the transmitter. The cooperation gain is studied in a system-wide perspective by taking into account the resource (power and bandwidth) consumed to establish the cooperation links. Built on that, the generalized cooperation spectral efficiency is defined.With a dedicated approximation, a near optimal resource allocation strategy is presented to maximize the cooperation spectral efficiency. Specially, the power allocation problem is simplified into a polynomial rooting problem. Simulation results show that the receiver cooperation can provide a performance gain and achieve the MIMO capacity. Moreover, performance loss incurred by the proposed method is negligible compared to the numerical exhaustive search scheme.