Network beamforming using relays with perfect channel information
IEEE Transactions on Information Theory
Bursty wideband relay networks
WCNC'09 Proceedings of the 2009 IEEE conference on Wireless Communications & Networking Conference
Bursty relay networks in low-SNR regimes
IEEE Transactions on Communications
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
Beamforming in wireless relay-interference networks with quantized feedback
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
Interference cancellation in distributed space-time coded wireless relay networks
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Mobile Networks and Applications
An optimal PSO distributed precoding algorithm in QRD-based multi-relay system
Future Generation Computer Systems
Wireless Personal Communications: An International Journal
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We consider a dense fading multi-user network with multiple active multi-antenna source-destination pair terminals communicating simultaneously through a large common set of K multi-antenna relay terminals in the full spatial multiplexing mode. We use Shannon-theoretic tools to analyze the tradeoff between energy efficiency and spectral efficiency (known as the power-bandwidth tradeoff) in meaningful asymptotic regimes of signal-to-noise ratio (SNR) and network size. We design linear distributed multi-antenna relay beamforming (LDMRB) schemes that exploit the spatial signature of multi-user interference and characterize their power-bandwidth tradeoff under a system-wide power constraint on source and relay transmissions. The impact of multiple users, multiple relays and multiple antennas on the key performance measures of the high and low SNR regimes is investigated in order to shed new light on the possible reduction in power and bandwidth requirements through the usage of such practical relay cooperation techniques. Our results indicate that point-to-point coded multi-user networks supported by distributed relay beamforming techniques yield enhanced energy efficiency and spectral efficiency, and with appropriate signaling and sufficient antenna degrees of freedom, can achieve asymptotically optimal power-bandwidth tradeoff with the best possible (i.e., as in the cutset bound) energy scaling of K-1 and the best possible spectral efficiency slope at any SNR for large number of relay terminals. Furthermore, our results help to identify the role of interference cancellation capability at the relay terminals on realizing the optimal power- bandwidth tradeoff; and show how relaying schemes that do not attempt to mitigate multi-user interference, despite their optimal capacity scaling performance, could yield a poor power- bandwidth tradeoff.