MMSE-Based Transceiver Design Algorithms for Interference MIMO Relay Systems

Abstract

In this paper, we investigate the transceiver design for amplify-and-forward interference multiple-input multipleoutput (MIMO) relay communication systems, where multiple transmitter-receiver pairs communicate simultaneously with the aid of a relay node. The aim is to minimize the mean-squared error (MSE) of the signal waveform estimation at the receivers subjecting to transmission power constraints at the transmitters and the relay node. As the transceiver optimization problem is nonconvex with matrix variables, the globally optimal solution is intractable to obtain. To overcome the challenge, we propose an iterative transceiver design algorithm where the transmitter, relay, and receiver matrices are optimized iteratively by exploiting the optimal structure of the relay precoding matrix. To reduce the computational complexity of optimizing the relay precoding matrix, we propose a simplified relay matrix design through modifying the transmission power constraint at the relay node. The modified relay optimization problem has a closedform solution. Simulation results demonstrate that the proposed algorithms perform better than the existing techniques in terms of both MSE and bit-error-rate.

Joint source and relay optimization for interference MIMO relay networks

“…Thus the complexity of the iterative algorithms is often reasonably high. Note that the sum-MSE based iterative algorithms proposed in [8][9][10] have similar complexity orders. Hence in the following subsection, we contrive an algorithm for the joint optimization problem such that the computational overhead is substantially reduced.…”

“…5, the BER performance of the proposed twoway relaying algorithms has been compared with the sum-MSE-based algorithms originally proposed for oneway relaying in [8][9][10]. QPSK signal constellations were assumed to modulate the transmitted signals.…”

“…We set N s = 2, K = 3, N r = KN s , N d = 6, P r = 20 dB, and transmit 1000N s randomly generated bits from each transmitter in each channel realization. Most importantly, the iterative sum-MSE minimization algorithms in [8][9][10] always penalize the user with the worst channel condition in the two-way relaying system.…”

“…1 The min-max MSE criterion is considered by many to be more desirable than the min-sum MSE criterion in [8][9][10] because fairness is imposed and weaker users are not being sacrificed for the minimization of the sum.…”

Distributed Multi-Stream Beamforming in MIMO Multi-Relay Interference Networks

“…8], the mean square error (MSE) minimization problems are more tractable in relay networks with the three features. Nevertheless, the studies on MSE are still limited [19], and to the best of our knowledge, the MSE problem in a relay network with all the three features is studied only in [20].…”