Can Uplink Weights be Used for Downlink in TDD DS-CDMA Systems with Base Station Antenna Array?
Summary :
For base station antenna array systems with time-division-duplex (TDD) mode, downlink channel responses are equal to uplink channel responses if the duplexing time is small, thus it is often believed that TDD mode simplies downlink beamforming problem as uplink weights can be applied for downlink directly. In this letter, we show that for TDD DS-CDMA systems, even though uplink and downlink channel responses are equal, optimal uplink weights are no longer equal to the optimal downlink ones due to asynchronous property in uplink and synchronous property in downlink, as well as different data rate traffic and QoS requirements. Computer simulations show that for asymmetric traffic, if uplink weights are used for downlink directly, downlink system capacity is less than 50% of that with optimal downlink weights.
- Publication
- IEICE TRANSACTIONS on Communications Vol.E85-B No.8 pp.1627-1630
- Publication Date
- 2002/08/01
- Publicized
- Online ISSN
- DOI
- Type of Manuscript
- LETTER
- Category
- Antenna and Propagation
Authors
Keyword
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Ying-Chang LIANG, "Can Uplink Weights be Used for Downlink in TDD DS-CDMA Systems with Base Station Antenna Array?" in IEICE TRANSACTIONS on Communications,
vol. E85-B, no. 8, pp. 1627-1630, August 2002, doi: .
Abstract: For base station antenna array systems with time-division-duplex (TDD) mode, downlink channel responses are equal to uplink channel responses if the duplexing time is small, thus it is often believed that TDD mode simplies downlink beamforming problem as uplink weights can be applied for downlink directly. In this letter, we show that for TDD DS-CDMA systems, even though uplink and downlink channel responses are equal, optimal uplink weights are no longer equal to the optimal downlink ones due to asynchronous property in uplink and synchronous property in downlink, as well as different data rate traffic and QoS requirements. Computer simulations show that for asymmetric traffic, if uplink weights are used for downlink directly, downlink system capacity is less than 50% of that with optimal downlink weights.
URL: https://global.ieice.org/en_transactions/communications/10.1587/e85-b_8_1627/_p
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@ARTICLE{e85-b_8_1627,
author={Ying-Chang LIANG, },
journal={IEICE TRANSACTIONS on Communications},
title={Can Uplink Weights be Used for Downlink in TDD DS-CDMA Systems with Base Station Antenna Array?},
year={2002},
volume={E85-B},
number={8},
pages={1627-1630},
abstract={For base station antenna array systems with time-division-duplex (TDD) mode, downlink channel responses are equal to uplink channel responses if the duplexing time is small, thus it is often believed that TDD mode simplies downlink beamforming problem as uplink weights can be applied for downlink directly. In this letter, we show that for TDD DS-CDMA systems, even though uplink and downlink channel responses are equal, optimal uplink weights are no longer equal to the optimal downlink ones due to asynchronous property in uplink and synchronous property in downlink, as well as different data rate traffic and QoS requirements. Computer simulations show that for asymmetric traffic, if uplink weights are used for downlink directly, downlink system capacity is less than 50% of that with optimal downlink weights.},
keywords={},
doi={},
ISSN={},
month={August},}
Copy
TY - JOUR
TI - Can Uplink Weights be Used for Downlink in TDD DS-CDMA Systems with Base Station Antenna Array?
T2 - IEICE TRANSACTIONS on Communications
SP - 1627
EP - 1630
AU - Ying-Chang LIANG
PY - 2002
DO -
JO - IEICE TRANSACTIONS on Communications
SN -
VL - E85-B
IS - 8
JA - IEICE TRANSACTIONS on Communications
Y1 - August 2002
AB - For base station antenna array systems with time-division-duplex (TDD) mode, downlink channel responses are equal to uplink channel responses if the duplexing time is small, thus it is often believed that TDD mode simplies downlink beamforming problem as uplink weights can be applied for downlink directly. In this letter, we show that for TDD DS-CDMA systems, even though uplink and downlink channel responses are equal, optimal uplink weights are no longer equal to the optimal downlink ones due to asynchronous property in uplink and synchronous property in downlink, as well as different data rate traffic and QoS requirements. Computer simulations show that for asymmetric traffic, if uplink weights are used for downlink directly, downlink system capacity is less than 50% of that with optimal downlink weights.
ER -
English
