TY - GEN
T1 - Bi-directional training for FDD systems
AU - Zhou, Hao
AU - Honig, Michael L.
AU - Liu, Jialing
AU - Xiao, Weimin
N1 - Publisher Copyright:
© 2019 IEEE.
PY - 2019/12
Y1 - 2019/12
N2 - We study distributed algorithms for joint adaptation of precoding and combining filters in frequency-division duplex (FDD) multiple-input multiple-output (MIMO) cellular systems. Neither the base stations nor the mobiles have a priori channel state information, and the transmit/receive filters are directly adapted through training. We propose extensions of bi- directional training (BiT), designed for time- division duplex (TDD) systems, to FDD systems where uplink-downlink reciprocity may not apply. A direct application of BiT can give mismatched precoders with substantial performance degradation. Our approach assumes angular reciprocity, that is, the channel multipath, which causes the frequency selectivity, is characterized by angles of arrival/departure that vary predictably with frequency. Hence spatial beams corresponding to angles of arrival can be turned around to point towards the corresponding angles of departure in the paired band. We present three methods based on this general approach with different complexity for angular estimation and selection. Simulation results indicate that when the multipath is sufficiently sparse, most of the achievable gain with channel reciprocity and TDD can be recovered.
AB - We study distributed algorithms for joint adaptation of precoding and combining filters in frequency-division duplex (FDD) multiple-input multiple-output (MIMO) cellular systems. Neither the base stations nor the mobiles have a priori channel state information, and the transmit/receive filters are directly adapted through training. We propose extensions of bi- directional training (BiT), designed for time- division duplex (TDD) systems, to FDD systems where uplink-downlink reciprocity may not apply. A direct application of BiT can give mismatched precoders with substantial performance degradation. Our approach assumes angular reciprocity, that is, the channel multipath, which causes the frequency selectivity, is characterized by angles of arrival/departure that vary predictably with frequency. Hence spatial beams corresponding to angles of arrival can be turned around to point towards the corresponding angles of departure in the paired band. We present three methods based on this general approach with different complexity for angular estimation and selection. Simulation results indicate that when the multipath is sufficiently sparse, most of the achievable gain with channel reciprocity and TDD can be recovered.
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U2 - 10.1109/GLOBECOM38437.2019.9013203
DO - 10.1109/GLOBECOM38437.2019.9013203
M3 - Conference contribution
AN - SCOPUS:85081949604
T3 - 2019 IEEE Global Communications Conference, GLOBECOM 2019 - Proceedings
BT - 2019 IEEE Global Communications Conference, GLOBECOM 2019 - Proceedings
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2019 IEEE Global Communications Conference, GLOBECOM 2019
Y2 - 9 December 2019 through 13 December 2019
ER -