Table of Contents Author Guidelines Submit a Manuscript
Wireless Communications and Mobile Computing
Volume 2017, Article ID 4063792, 7 pages
Research Article

A Comparative Study on the Performance of LLR- and SNR-Based Hybrid Relaying Schemes

1Faculty of Information Engineering and Technology, The German University in Cairo, Cairo, Egypt
2The German University in Cairo, Cairo, Egypt

Correspondence should be addressed to Wassim Alexan; ge.ude.cug@hpesoj.missaw

Received 23 July 2016; Accepted 7 September 2016; Published 10 January 2017

Academic Editor: Pierre-Martin Tardif

Copyright © 2017 Ahmed El-Mahdy and Wassim Alexan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A comparative study on the theoretical bit error rate (BER) is presented for hybrid relaying schemes that toggle between adaptive decode-and-forward (ADF) and amplify-and-forward (AF) protocols, for a typical three-node wireless network. Toggling between the two forwarding protocols is based on the log-likelihood ratio (LLR) or the signal-to-noise ratio (SNR) of the received signal at the relay node. Closed-form expressions for the probability of error are presented, as well as the expressions of the proposed schemes’ gains over classical ADF and AF protocols. Comparisons are carried out among the two schemes and other hybrid schemes found in the literature. Moreover, the impact of relay location on the probability of error is investigated.