Cooperative relay beamforming in IDMA communication networks

Abstract

In this paper, a new combination of Interleave division multiple access (IDMA) and spatial diversity offered by cooperativerelay aided distributed beam forming is proposed. In the offered scheme communication strategy consists two steps. All usersbroadcast their message to relays in the first step and then relays amplifies and forward the information to the desireddestination. IDMA, which is popular non-orthogonal multiple access (NOMA) technique is used to combat the effect ofmultiple access interference (MAI) at relay as well as destination nodes. Each relay processed the signal to maintain the QoSof destination. The goal of this work is to find the appropriate beam forming weights by minimising the transmit power andwithout compromising the QoS in terms of SINR. However power minimization is not the convex problem, so semi-definiterelaxation is used to modify the problem in to semi-definite programming (SDP) problem and the conventional SDP problemsolver CVX is used for solution. The numerical explanation and simulation experiment of the proposed scheme shows theperformance improvements in terms of bit error rate.