TY - GEN
T1 - Allocation of feedback bits among users in broadcast MIMO channels
AU - Clerckx, Bruno
AU - Kim, Gil
AU - Choi, Joonil
AU - Kim, Sungjin
PY - 2008
Y1 - 2008
N2 - Given a contraint on the total amount of feedback overhead, we investigate the allocation of feedback bits (i.e. codebook sizes) among users in a limited feedback Zero Forcing Beamforming-based MU-MIMO scheme where users have the opportunity to adapt their codebooks as a function of their own channel statistics. We consider both single-polarized and dual- polarized scenarios. Using upper bounds on the total rate loss incurred by quantization (previously derived by the authors), the optimal bit allocation strategy among users is derived as a function of the users channel statistics and SNR. Closed form solutions of the optimal bit allocation at low and high SNR are also derived. It is shown that in single-polarized scenarios (resp. dual-polarized scenarios) at high SNR it is beneficial to allocate more bits to users experiencing rank deficient transmit correlation matrices (resp. low cross-polarization discrimination XPD) than to users experiencing well conditioned correlation matrices (resp. large XPD), while an opposite allocation should be done at low SNR. Simulation results are shown to confirm analytical derivations.
AB - Given a contraint on the total amount of feedback overhead, we investigate the allocation of feedback bits (i.e. codebook sizes) among users in a limited feedback Zero Forcing Beamforming-based MU-MIMO scheme where users have the opportunity to adapt their codebooks as a function of their own channel statistics. We consider both single-polarized and dual- polarized scenarios. Using upper bounds on the total rate loss incurred by quantization (previously derived by the authors), the optimal bit allocation strategy among users is derived as a function of the users channel statistics and SNR. Closed form solutions of the optimal bit allocation at low and high SNR are also derived. It is shown that in single-polarized scenarios (resp. dual-polarized scenarios) at high SNR it is beneficial to allocate more bits to users experiencing rank deficient transmit correlation matrices (resp. low cross-polarization discrimination XPD) than to users experiencing well conditioned correlation matrices (resp. large XPD), while an opposite allocation should be done at low SNR. Simulation results are shown to confirm analytical derivations.
UR - http://www.scopus.com/inward/record.url?scp=67249121412&partnerID=8YFLogxK
U2 - 10.1109/GLOCOM.2008.ECP.630
DO - 10.1109/GLOCOM.2008.ECP.630
M3 - Conference contribution
AN - SCOPUS:67249121412
SN - 9781424423248
T3 - GLOBECOM - IEEE Global Telecommunications Conference
SP - 3282
EP - 3286
BT - 2008 IEEE Global Telecommunications Conference, GLOBECOM 2008
T2 - 2008 IEEE Global Telecommunications Conference, GLOBECOM 2008
Y2 - 30 November 2008 through 4 December 2008
ER -