Efficient feedback signaling using multi-channel selection diversity for multi-user MIMO systems

Recently, a number of techniques have been introduced to improve sum-rate performance of a wireless multiple-input multiple-output (MIMO) broadcast channel (BC). However, previous works have ignored the rate overhead associated with feedback of MIMO BC channel state information (CSI), which increases in proportion to the number of users in multi-user MIMO communications. Considering the limited amount of feedback signaling in a practical system, the effective feedback transmission as a form of partial CSI is required. In this paper, a novel scheme is proposed, of which the sum-rate performance approaches extremely close to the sum capacity of MIMO BC as the number of users increases, while the feedback overhead is designed to be reduced down to the number of active channel vectors. In our proposed scheme, multi-channel selection diversity (MCSD) is exploited to send partial CSI back to the transmitter.