Modified K-best breadth-first assisted antenna selection for dual-hop MIMO AF multiple-relay systems in correlated channels

An efficient antenna-pair selection scheme is proposed for a non-regenerative dual-hop amplify-and-forward (AF) multiple-input multiple-output (MIMO) multiple-relay system in which multiple antennas are placed at each node over correlated fading channels in the paper. The design of multiple-relay antenna-pair selection can be transformed into a modified K-best tree search structure based on the signal-to-noise ratio (SNR) maximization criterion. This two-level antenna selection strategy selects a subset of antenna pairs from available relays based on the concept of the K-best breadth-first search mechanism in conjunction with the harmonic mean and norm metrics subject to (s.t.) either optimal- or equal-power allocation constraints across the activated antenna pairs. Consequently, the use of the proposed antenna selection achieves a substantial saving in system hardware complexity of the multiple radio frequency (RF) chains associated with multiple antennas without compromising the symbol-error-rate (SER) performance when compared to existing antenna selection schemes for half-duplex AF MIMO relay networks.