Simulated annealing techniques for joint transmitter-receiver design in a multiple user access MIMO-OFDM channel

In this paper we consider the problem of the joint design of multiple transmitters and receivers in a MIMe- eFDM scenario. We consider that both the transmitters and receivers have multiple antennas, configuring a Multi-Input-Multi-Output (MIMe) channel. Based on this structure, space diversity techniques can be used to separate the signals transmitted by different users. Concretely, the proposed approach consists in beamforming at both sides of the system, combined with the Orthogonal-Frequency-Division-Multiplexing (eFDM) modulation. The goal is the minimization of the total transmitted power subject to constraints related to the Quality of Service (QoS) for each user in terms of the Bit Error Rate (BER) and the maximum transmitted power for some terminals. By making use of this approach, the Multiple Access Interference (MAI) is minimized and the physical resources are exploited in an optimum way. The design is based on Simulated Annealing (SA), an heuristic technique able to find the optimum design in this non-convex problem and that can take into account all kind of constraints