Cooperative Fading Regions for Decode and Forward Relaying

• Published in: IEEE transactions on information theory 2008-11, Vol.54 (11), p.4908-4924
• Main Authors: Savazzi, S., Spagnolini, U.
• Format: Article
• Language: English
• Subjects: Access methods and protocols, osi model; Antennas; Applied sciences; Channels; Codes; Collaboration; Communication channels; Cooperative diversity; cooperative transmissions; Data transmission; decode and forward relaying; Decoding; distributed space-time coding; Exact sciences and technology; Fading; fading channels; Gain; Information analysis; Information science; Information theory; Information, signal and communications theory; Outages; Performance analysis; Probability; Protocol (computers); Protocols; Radiocommunications; Rayleigh channels; Relaying; Relays; Statistics; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Teleprocessing networks. Isdn; Transmission and modulation (techniques and equipments); Wireless communication; Wireless communications
• ISSN: 0018-9448; 1557-9654
• DOI: 10.1109/TIT.2008.929911

Cooperative transmission protocols over fading channels are based on a number of relaying nodes to form virtual multi-antenna transmissions. Diversity provided by these techniques has been widely analyzed for the Rayleigh fading case. However, short range or fixed wireless communications often experience propagation environments where the fading envelope distribution is meaningfully different from Rayleigh. The main focus in this paper is to investigate the impact of fading distribution on performances of collaborative communication. Cooperative protocols are compared to co-located multi-antenna systems by introducing the concept of cooperative fading region. This is the collection of fading distributions for which relayed transmission can be regarded as a competitive option (in terms of performances) compared to multi-antenna direct (noncooperative) transmission. The analysis is dealt with by adopting the information theoretic outage probability as the performance metric. Cooperative link performances at high SNR are conveniently expressed here in terms of diversity and coding gain as outage parameters that are provided by the fading statistics of the channels involved in collaborative transmission. Advantages of cooperative transmission compared to multi-antenna are related to the propagation environment so that the analysis can be used in network design.