Recovering Cooperative Multiplexing Gain in Wireless Relay Networks

• Published in: IEEE transactions on communications Vol. 58; no. 12; pp. 3538 - 3549
• Main Authors: Yang, Tao, Yuan, Jinhong, Zhang, Wei
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas; Applied sciences; Degrees of freedom; Exact sciences and technology; Fading; Frequency division multiplexing; Gain; Information theory; Information, signal and communications theory; Mathematical analysis; MIMO; Multiplexing; multiplexing gain; Networks; Protocols; Radiocommunications; Relay; relay channel; Relays; Signal and communications theory; Signal to noise ratio; Studies; Telecommunications; Telecommunications and information theory; User-cooperation; Wireless communication; Wireless networks; Multiplexing; MIMO system; Relay; Relay network; Wireless telecommunication; multiplexing gain; Information analysis; User-cooperation; Duplex process; Relay channel; Frequency band; Wireless network; Numerical simulation; MIMO; Uplink; Antenna; Signal to noise ratio; Information theory
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2010.093010.090731

We consider an uplink communication in a wireless network where each source-user is assisted by M half-duplex relays. The source users and relays are equipped with single-antenna whereas the destination has N antennas. We show that the degree of freedom (d.o.f.) of this network is limited by the links from the source to the collection of relays and destination. This phenomenon is referred to as a "d.o.f. bottleneck problem" which compromise the cooperative multiplexing gain (CMG) and the achievable rate of the system. To improve the CMG, we propose an auxiliary frequency bands (AFBs)-based approach to tackle the d.o.f. bottleneck problem. Information theoretic analysis and numerical results show that the proposed scheme can achieve a CMG of min(M+1,N) when the number of AFBs is sufficiently large. As compared with conventional cooperative communications, the improved multiplexing gain of the proposed scheme is translated into tremendously increased achievable rate at a relatively high SNR.