Performance Analysis of Turbo-Coded Decode-and-Forward Relay Channels with Middleton Class-A Impulsive Noise

Abstract

Relays are used to improve wireless network performances. In this paper, the decode-and-forward relaying technique is used to achieve spatial diversity. We considered a system with a symmetric turbo coded relay and its three channels (source-relay, source-destination and relay-destination) affected by impulsive noise. The statistic model used for noise was Middleton additive white Class-A. The performances are evaluated by investigating the system behavior when at destination the traditional iterative decoder and the heuristically modified iterative decoder proposed by Huynh are used. The simulations were made for different parameter values of the noise model and they showed that in high impulsive noise conditions, the relay system offers better performance than the direct link. However, when the source-destination channel is weak, the traditional iterative decoder assures an additional gain than the heuristically modified one. When the Gaussian component is dominant, the relay system ensures better performances, but only at high values of Signal-to-Noise Ratio. In this case, the heuristically modified decoder, with conveniently chosen value for alpha, is better than the traditional one in terms of bit error rate.

Keywords

• decode-and-forward
• impulsive noise
• iterative decoder
• relay channels
• turbo codes