Differential Modulations for Multinode Cooperative Communications

Abstract--This paper proposes and analyzes differential modulation schemes for two cooperation protocols in multinode cooperative wireless networks; namely, multinode differential amplify-and-forward scheme (DiffAF) and multinode differential decode-and-forward scheme (DiffDF). In the DiffAF scheme, with knowledge of long-term average of received signals from all communication links, the destination efficiently combines signals from direct and all multiple-relay links to improve communication reliability. In the DiffDF scheme, by utilizing a decision threshold at each relay-destination link, the destination efficiently combines signals from the direct link and each relay link whose signal amplitude is larger than the threshold. For the DiffAF scheme, an exact bit error rate (BER) formulation based on optimum combining is provided for differential -ary phase shift keying (DMPSK) modulation, and it serves as a performance benchmark of the proposed DiffAF scheme. In addition, BER upper bo...

• Type: Journal
• Year: 2008
• Where: TSP
• Authors: Thanongsak Himsoon, W. Pam Siriwongpairat, Weifeng Su, K. J. Ray Liu
• Keywords: DiffAF Scheme, DiffDF Scheme, Optimum Power Allocation, TSP 2008