TY - GEN
T1 - Comparison of multiuser diversity using STBC and transmit beamforming with outdated feedback
AU - Ma, Qian
AU - Tepedelenlioglu, Cihan
PY - 2005
Y1 - 2005
N2 - For multiuser diversity systems employing adaptive modulation, we compare the spectral efficiency for space-time block coding (STBC) and transmit beamforming (BF) with outdated channel feedback. Taking into account the channel feedback delay, we derive the optimal thresholds to maximize spectral efficiency subject to an average BER constraint, and illustrate the impact of feedback delay on the achievable multiuser diversity gain with either STBC or BF. We observe that more transmit antennas bring higher spectral efficiency for BF. But this becomes inverted using STBC, due to the effect of channel-hardening [1]. With a small feedback delay, the BF scheme outperforms the STBC scheme. However, when feedback delay becomes large enough, the STBC scheme achieves higher spectral efficiency due to the reduced diversity order of BF.
AB - For multiuser diversity systems employing adaptive modulation, we compare the spectral efficiency for space-time block coding (STBC) and transmit beamforming (BF) with outdated channel feedback. Taking into account the channel feedback delay, we derive the optimal thresholds to maximize spectral efficiency subject to an average BER constraint, and illustrate the impact of feedback delay on the achievable multiuser diversity gain with either STBC or BF. We observe that more transmit antennas bring higher spectral efficiency for BF. But this becomes inverted using STBC, due to the effect of channel-hardening [1]. With a small feedback delay, the BF scheme outperforms the STBC scheme. However, when feedback delay becomes large enough, the STBC scheme achieves higher spectral efficiency due to the reduced diversity order of BF.
UR - http://www.scopus.com/inward/record.url?scp=33646790841&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33646790841&partnerID=8YFLogxK
U2 - 10.1109/ICASSP.2005.1415912
DO - 10.1109/ICASSP.2005.1415912
M3 - Conference contribution
AN - SCOPUS:33646790841
SN - 0780388747
SN - 9780780388741
T3 - ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings
SP - III1125-III1128
BT - 2005 IEEE International Conference on Acoustics, Speech, and Signal Processing,ICASSP '05 - Proceedings - Audio and ElectroacousticsSignal Processing for Communication
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP '05
Y2 - 18 March 2005 through 23 March 2005
ER -