Joint iterative power allocation and relay selection for cooperative MIMO systems using discrete stochastic algorithms

In this work, we propose a set of joint power allocation and relay selection (RS) algorithms for multi-relay cooperative multiple-input-multiple-output (MIMO) systems. Adaptive discrete stochastic algorithms (DSA) are used to generate a subset of relays over which stochastic gradient continuous power allocation operates. Optimum minimum mean-square error (MMSE) and adaptive reception are considered in a decode-and-forward (DF) network with a non-negligible direct path. Bit-error-rate (BER) comparisons are given against systems which lack joint RS and power allocation, and the proposed schemes are shown to achieve an increased rate of convergence, improved steady-state performance and involve the manipulation of smaller dimensionality matrices.