TY - JOUR
T1 - Training and feedback optimization for multiuser MIMO downlink
AU - Kobayashi, Mari
AU - Jindal, Nihar
AU - Caire, Giuseppe
PY - 2011/8
Y1 - 2011/8
N2 - We consider a MIMO fading broadcast channel where the fading channel coefficients are constant over time-frequency blocks that span a coherent time × a coherence bandwidth. In closed-loop systems, channel state information at transmitter (CSIT) is acquired by the downlink training sent by the base station and an explicit feedback from each user terminal. In open-loop systems, CSIT is obtained by exploiting uplink training and channel reciprocity. We use closed-form lower bounds and tight approximations of the ergodic achievable rate in the presence of CSIT errors in order to optimize the overall system throughput, by taking explicitly into account the overhead due to channel estimation and channel state feedback. Based on three time-frequency block models inspired by actual systems, we provide useful guidelines for the overall system optimization. In particular, digital (quantized) feedback is found to offer a substantial advantage over analog (unquantized) feedback.
AB - We consider a MIMO fading broadcast channel where the fading channel coefficients are constant over time-frequency blocks that span a coherent time × a coherence bandwidth. In closed-loop systems, channel state information at transmitter (CSIT) is acquired by the downlink training sent by the base station and an explicit feedback from each user terminal. In open-loop systems, CSIT is obtained by exploiting uplink training and channel reciprocity. We use closed-form lower bounds and tight approximations of the ergodic achievable rate in the presence of CSIT errors in order to optimize the overall system throughput, by taking explicitly into account the overhead due to channel estimation and channel state feedback. Based on three time-frequency block models inspired by actual systems, we provide useful guidelines for the overall system optimization. In particular, digital (quantized) feedback is found to offer a substantial advantage over analog (unquantized) feedback.
KW - Channel estimation
KW - channel etate information feedback
KW - MIMO broadcast channel
KW - multiuser MIMO downlink
UR - http://www.scopus.com/inward/record.url?scp=80052071600&partnerID=8YFLogxK
U2 - 10.1109/TCOMM.2011.051711.090752
DO - 10.1109/TCOMM.2011.051711.090752
M3 - Article
AN - SCOPUS:80052071600
SN - 0090-6778
VL - 59
SP - 2228
EP - 2240
JO - IEEE Transactions on Communications
JF - IEEE Transactions on Communications
IS - 8
M1 - 5773636
ER -