Two-Level MMSE Relay Strategy for an AF Wireless Relay Network

Abstract

This paper presents optimal amplify-and-forward (AF) relay amplifying matrices based on the minimum mean square error (MMSE) criterion for a cooperative AF wireless relay network consisting of a one-source-one-destination pair node and two-level N relay nodes. During data transmission, power is constrained at the source node, at the relay nodes in both the first and the second levels, and at the destination node. In addition, this paper considers the case that power is intentionally not constrained. Hence, for the no-power constraint example, a positive scaling factor is employed to meet the target signal-tonoise ratio (SNR_TGT ) at the destination node. With the derived optimal relay amplifying matrices, bit error rate of the wireless relay network under both power and no-power constraint is simulated.