Performance analysis of distributed space-time coded protocols for wireless multi-hop communications

• Published in: IEEE transactions on wireless communications Vol. 9; no. 1; pp. 122 - 133
• Main Authors: Vajapeyam, M., Mitra, U.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.01.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Access methods and protocols, osi model; Applied sciences; Approximation; Coding, codes; Communication; Cooperative diversity methods; Detection, estimation, filtering, equalization, prediction; Diversity methods; Error analysis; Exact sciences and technology; Gain; Hops; Information, signal and communications theory; Large-scale systems; Mathematical analysis; MIMO fading channels; Pairwise error probability; Performance analysis; Performance enhancement; Relays; Signal and communications theory; Signal to noise ratio; Signal, noise; Spread spectrum communication; Strategy; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Teleprocessing networks. Isdn; Transmission and modulation (techniques and equipments); Wireless application protocol; Wireless communication; Wireless sensor networks; Fading channels; Performance evaluation; MIMO system; High performance; Space-time codes; Relay; Error probability; Cooperative diversity methods; MIMO fading channels; Wireless telecommunication; Space diversity; Square matrix; Transmission protocol; Cooperative systems; Multihop network; Telecommunication network; Sensor array; Signal detection; Signal to noise ratio
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2010.01.071135

In resource limited, large scale sensor networks, cooperative communication over multiple hops offers opportunities to save power: intermediate nodes between source and destination act as cooperative relays. In order to exploit spatial diversity, protocols coupled with space-time coding strategies are proposed herein and analyzed for distributed cooperative communication. In contrast to prior work, multi-hop (versus two-hop) schemes are developed and analyzed for amplify-and forward type of communication protocols. First, the Alamouti based two-hop scheme proposed by Hua et al and analyzed by Jing & Hassibi is generalized to an arbitrary number of hops L, and a general approximation for the pairwise error probability (PEP) at high SNR is obtained. This expression is used to provide a close approximation to the achievable diversity gain of the scheme. It is further shown that the diversity decreases with L, for large, but finite signal-to-noise ratio (SNR). This motivates the subsequent development of new distributed multihop protocols to mitigate the diversity losses and, hence, yield improved performance. This work presents two such strategies as well as their diversity characterization, which are analyzed for the specific case of L = 3 hops and shown to exhibit improved performance at high SNR. These schemes are based on the structure of the rate-half codes proposed by Tarokh and the square-matrix embeddable codes of Tirkkonen & Hottinen.