CaltechAUTHORS
  A Caltech Library Service

A Comparison of Time-Sharing, DPC, and Beamforming for MIMO Broadcast Channels With Many Users

Sharif, Masoud and Hassibi, Babak (2007) A Comparison of Time-Sharing, DPC, and Beamforming for MIMO Broadcast Channels With Many Users. IEEE Transactions on Communications, 55 (1). pp. 11-15. ISSN 0090-6778. http://resolver.caltech.edu/CaltechAUTHORS:SHAieeetc07

[img]
Preview
PDF
See Usage Policy.

180Kb

Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:SHAieeetc07

Abstract

In this letter, we derive the scaling laws of the sum rate for fading multiple-input multiple-output Gaussian broadcast channels using time sharing to the strongest user, dirty-paper coding (DPC), and beamforming, when the number of users (receivers) n is large. Throughout the letter, we assume a fix average transmit power and consider a block-fading Rayleigh channel. First, we show that for a system with M transmit antennas and users equipped with N antennas, the sum rate scales like M log logn N for DPC, and beamforming when M is fixed and for any N (either growing to infinity or not). On the other hand, when both M and N are fixed, the sum rate of time sharing to the strongest user scales like min(M,N)log log n. Therefore, the asymptotic gain of DPC over time sharing for the sum rate is (M/min(M,N)) when M and N are fixed. It is also shown that if M grows as logn, the sum rate of DPC and beamforming will grow linearly in M, but with different constant multiplicative factors. In this region, the sum-rate capacity of time-sharing scales like N log log n.


Item Type:Article
Additional Information:© Copyright 2007 IEEE. Reprinted with permission. Paper approved by B. Hochwald, the Editor for Communication and Coding Theory of the IEEE Communications Society. Manuscript received May 15, 2004; revised June 6, 2006. [Posted online: 2007-01-15] This work was supported in part by the National Science Foundation under Grant CCR-0133818, in part by the Office of Naval Research under Grant N00014-02-1-0578, and in part by Caltech’s Lee Center for Advanced Networking. This paper was presented in part at the IEEE International Symposium on Information Theory, Chicago, IL, 2004.
Subject Keywords:Block-fading channel, broadcast channels, dirty-paper coding, multiple antennas, sum-rate capacity.
Record Number:CaltechAUTHORS:SHAieeetc07
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:SHAieeetc07
Alternative URL:http://dx.doi.org/10.1109/TCOMM.2006.887480
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7549
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:02 Mar 2007
Last Modified:26 Dec 2012 09:32

Repository Staff Only: item control page