Robust collaborative-relay beamforming
IEEE Transactions on Signal Processing
On multicast beamforming for minimum outage
IEEE Transactions on Wireless Communications
Transmit precoding design for multi-antenna multicast broadcast services with limited feedback
WCNC'09 Proceedings of the 2009 IEEE conference on Wireless Communications & Networking Conference
IEEE Transactions on Signal Processing
Rank-constrained separable semidefinite programming with applications to optimal beamforming
IEEE Transactions on Signal Processing
Capacity limits of multi-antenna multicasting under correlated fading channels
IEEE Transactions on Communications
Wireless multicast scheduling with switched beamforming antennas
IEEE/ACM Transactions on Networking (TON)
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The problem of transmit beamforming to multiple cochannel multicast groups is considered for the important special case when the channel vectors are Vandermonde. This arises when a uniform linear antenna antenna (ULA) array is used at the transmitter under far-field line-of-sight propagation conditions, as provisioned in 802.16e and related wireless backhaul scenarios. Two design approaches are pursued: (i) minimizing the total transmitted power subject to providing at least a prescribed received signal-to-interference-plus-noise-ratio (SINR) to each intended receiver; and (ii) maximizing the minimum received SINR under a total transmit power budget. Whereas these problems have been recently shown to be NP-hard, in general, it is proven here that for Vandermonde channel vectors, it is possible to recast the optimization in terms of the autocorrelation sequences of the sought beam vectors, yielding an equivalent convex reformulation. This affords efficient optimal solution using modern interior point methods. The optimal beam vectors can then be recovered using spectral factorization. Robust extensions for the case of partial channel state information, where the direction of each receiver is known to lie in an interval, are also developed. Interestingly, these also admit convex reformulation. The various optimal designs are illustrated and contrasted in a suite of pertinent numerical experiments.