On the Design of Amplify-and-Forward MIMO-OFDM Relay Systems With QoS Requirements Specified as Schur-Convex Functions of the MSEs

Abstract

In this letter, we focus on the design of linear and non-linear architectures in amplify-and-forward multiple-input multiple-output orthogonal frequency-division multiplexing relay networks in which different types of services are supported. The goal is to jointly optimize the processing matrices so as to minimize the total power consumption while satisfying the quality-of-service requirements of each service specified as Schurconvex functions of the mean square errors over all assigned subcarriers. It turns out that the optimal solution leads to the diagonalization of the source-relay-destination channel up to a unitary matrix depending on the specific Schur-convex function.

Convex Separable Problems With Linear Constraints in Signal Processing and Communications

“…Constrained optimization problems of the form (1) arise in connection with a wide range of power allocation problems in different applications and settings in signal processing and communications. For example, they arise in connection with the design of multiple-input multiple-output (MIMO) systems dealing with the minimization of the power consumption while meeting the quality-of-service (QoS) requirements over each data stream (see for example [1], [2], [3], [4], [5] for point-topoint communications and [6], [7], [8], [9], [10] for amplifyand-forward relay networks). A survey of some of these problems for point-to-point MIMO communications can be found in [11].…”

Joint Transceiver Optimization for Two-Way MIMO Relay Systems With MSE Constraints

“…In practical systems, MSE effectively measures the accuracy of the signal waveform estimation at the receivers. Moreover, MSE is directly related to other commonly used QoS criteria such as the system BER and the sourcedestination mutual information [9]. The problem (10)- (11) is nonconvex with matrix variables, and the globally optimal solution is computationally intractable to obtain.…”

“…Since W 1 and W 2 do not appear in the objective function (10), for any fixed B 1 , B 2 , and F, we choose W i to minimize MSE i in (9). The optimal W i is the Wiener filter given by…”

“…Note that in practical communication systems, QoS criteria are very important, as they greatly affect the user experience. For one-way MIMO relay systems, the QoS-constrained source and relay precoding matrices design has been studied in [9]- [11]. However, the approach in [9]- [11] cannot be applied to two-way MIMO relay systems.…”

Performance of MIMO MC-CDMA system with channel estimation equalization and relay

“…DF relays have higher computational complexity due to the requirement of decoding the signals and are helpful only if they can decode successfully the signals. Compared to DF relays, AF relays have the advantage of simpler signal processing and end-to-end transparency of data transmission, so it can be used flexibly in heterogeneous networks comprising of many nodes of different complexity or standards [13,14]. Fig.…”