Skip to main content
Open Access Publications from the University of California

UC Irvine

UC Irvine Previously Published Works bannerUC Irvine

Outage-Optimized Multicast Beamforming With Distributed Limited Feedback


We consider a slowly fading multicast channel with one T -antenna transmitter and K single-antenna receivers with the goal of minimizing channel outage probability using quantized beamforming. Our focus is on a distributed limited feedback scenario where each receiver can only quantize and send feedback information regarding its own receiving channels. A classical result in point-to-point quantized beamforming is that a necessary and sufficient condition for full diversity is to have log2 T bits from the receiver with an appropriate quantizer. We first generalize this result to multicast beamforming systems and show that a necessary and sufficient condition to achieve full diversity for all receivers is to have log2T bits from each receiver with an appropriate quantizer. Achievable diversity gains with a long-term power constraint are also discussed. Moreover, for a two-receiver system and with R feedback bits per receiver, we show that the outage performance with quantized beamforming is within O\left(2-R32T2right) dBs to the performance with full channel state information at the transmitter (CSIT). This constitutes, in the context of multicast channels, the first example of a distributed limited feedback scheme whose performance can provably approach the performance with full CSIT. Numerical simulations confirm our analytical findings.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View