Stream selection methods for non-regenerative MIMO relay networks

Abstract

For general MIMO relay AF networks, transmitting different number of data streams lead to significantly different performances. Therefore stream selection is an important preprocessing to maximize the sum rate. We first show that the problem to select only one stream for networks with single antenna users is NP-hard. Then based on the Total Signal to Total Interference plus Noise Ratio model, the stream selection problem for the general MIMO relay AF network is simplified as a 0–1 quadratic programming. Two stream selection algorithms are proposed. One is to delete streams from the full set and the other is to add streams to the basic set. Simulations show that the two algorithms are efficient to achieve high sum rate in medium to high SNR and in low SNR scenarios, respectively; the model with the stream selection as preprocess well balances between the achieved sum rate and the computational cost.