TY - GEN
T1 - Vector broadcast channels
T2 - 2011 IEEE International Symposium on Information Theory Proceedings, ISIT 2011
AU - Samarasinghe, Tharaka
AU - Inaltekin, Hazer
AU - Evans, Jamie
PY - 2011
Y1 - 2011
N2 - Threshold feedback policies are well known and provably rate-wise optimal selective feedback techniques for communication systems requiring partial channel state information (CSI). However, optimal selection of thresholds at mobile users to maximize information theoretic data rates subject to feedback constraints is an open problem. In this paper, we focus on the optimal threshold selection problem, and provide a solution for this problem for finite feedback systems. Rather surprisingly, we show that using the same threshold values at all mobile users is not always a rate-wise optimal feedback strategy, even for a system with identical users experiencing statistically the same channel conditions. By utilizing the theory of majorization, we identify an underlying Schur-concave structure in the rate function and obtain sufficient conditions for a homogenous threshold feedback policy to be optimal. Our results hold for most fading channel models, and we illustrate an application of our results to familiar Rayleigh fading channels.
AB - Threshold feedback policies are well known and provably rate-wise optimal selective feedback techniques for communication systems requiring partial channel state information (CSI). However, optimal selection of thresholds at mobile users to maximize information theoretic data rates subject to feedback constraints is an open problem. In this paper, we focus on the optimal threshold selection problem, and provide a solution for this problem for finite feedback systems. Rather surprisingly, we show that using the same threshold values at all mobile users is not always a rate-wise optimal feedback strategy, even for a system with identical users experiencing statistically the same channel conditions. By utilizing the theory of majorization, we identify an underlying Schur-concave structure in the rate function and obtain sufficient conditions for a homogenous threshold feedback policy to be optimal. Our results hold for most fading channel models, and we illustrate an application of our results to familiar Rayleigh fading channels.
UR - http://www.scopus.com/inward/record.url?scp=80054826295&partnerID=8YFLogxK
U2 - 10.1109/ISIT.2011.6033883
DO - 10.1109/ISIT.2011.6033883
M3 - Conference proceeding contribution
AN - SCOPUS:80054826295
SN - 9781457705960
SP - 1906
EP - 1910
BT - 2011 IEEE International Symposium on Information Theory Proceedings
PB - Institute of Electrical and Electronics Engineers (IEEE)
CY - Piscataway, NJ
Y2 - 31 July 2011 through 5 August 2011
ER -