The Optimum Channel Estimation for Coherent Receivers in Multicarrier CDMA System with Antenna Array

Masahiro FUJII; Rie SHIMIZU; Makoto ITAMI; Kohji ITOH

The Optimum Channel Estimation for Coherent Receivers in Multicarrier CDMA System with Antenna Array

Masahiro FUJII, Rie SHIMIZU, Makoto ITAMI, Kohji ITOH

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It is well known that diversity performance of communication systems using signals with high dimensions in time, frequency and/or spatial domains depends on correlation of the channel characteristics along signal dimensions. On the other hand, it has not been payed due attention how the coherent receiver which combines the signals is greatly affected by the erroneous channel estimation which can undermine the diversity gain. In this paper, assuming that the estimator is given the a priori probability of the channel characteristics, we propose an optimum estimation scheme based on MAP criterion, in an uplink-MC/CDMA system on channels with frequency selective fading, with an array of antennas at the receiver. The MAP estimator effectively takes into account the correlation of the channel characteristics that the conventional estimator neglects. We also propose a signal design in pilot symbol periods that enables the receiver to separately obtain the sufficient statistic for estimating the channel characteristics without MAI. Using computer simulation, we obtained MSE error performances of the proposed estimator compared with the conventional estimator and their effect on BER performances of the diversity combining receiver. It was observed that using the conventional estimator for combining greater number of signals than the effective channel dimension deteriorated the BER performance while using the proposed estimator kept the optimum performance just as the error-free estimator did. Also obtained for MC/CDMA systems are BER performances of the single user matched filter and MMSE receivers using the proposed and the conventional estimators. A considerable improvement of the MMSE performance was achieved owing to the optimum estimator. It remains for the a priori probability of the channel characteristics to be properly assumed and dealt with in sequential estimation.

Publication: IEICE TRANSACTIONS on Communications Vol.E86-B No.1 pp.365-374

Publication Date: 2003/01/01

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Type of Manuscript: Special Section PAPER (Special Issue on Multiple Access and Signal Transmission Techniques for Future Mobile Communications)

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Masahiro FUJII, Rie SHIMIZU, Makoto ITAMI, Kohji ITOH, "The Optimum Channel Estimation for Coherent Receivers in Multicarrier CDMA System with Antenna Array" in IEICE TRANSACTIONS on Communications, vol. E86-B, no. 1, pp. 365-374, January 2003, doi: .
Abstract: It is well known that diversity performance of communication systems using signals with high dimensions in time, frequency and/or spatial domains depends on correlation of the channel characteristics along signal dimensions. On the other hand, it has not been payed due attention how the coherent receiver which combines the signals is greatly affected by the erroneous channel estimation which can undermine the diversity gain. In this paper, assuming that the estimator is given the a priori probability of the channel characteristics, we propose an optimum estimation scheme based on MAP criterion, in an uplink-MC/CDMA system on channels with frequency selective fading, with an array of antennas at the receiver. The MAP estimator effectively takes into account the correlation of the channel characteristics that the conventional estimator neglects. We also propose a signal design in pilot symbol periods that enables the receiver to separately obtain the sufficient statistic for estimating the channel characteristics without MAI. Using computer simulation, we obtained MSE error performances of the proposed estimator compared with the conventional estimator and their effect on BER performances of the diversity combining receiver. It was observed that using the conventional estimator for combining greater number of signals than the effective channel dimension deteriorated the BER performance while using the proposed estimator kept the optimum performance just as the error-free estimator did. Also obtained for MC/CDMA systems are BER performances of the single user matched filter and MMSE receivers using the proposed and the conventional estimators. A considerable improvement of the MMSE performance was achieved owing to the optimum estimator. It remains for the a priori probability of the channel characteristics to be properly assumed and dealt with in sequential estimation.
URL: https://global.ieice.org/en_transactions/communications/10.1587/e86-b_1_365/_p

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@ARTICLE{e86-b_1_365,
author={Masahiro FUJII, Rie SHIMIZU, Makoto ITAMI, Kohji ITOH, },
journal={IEICE TRANSACTIONS on Communications},
title={The Optimum Channel Estimation for Coherent Receivers in Multicarrier CDMA System with Antenna Array},
year={2003},
volume={E86-B},
number={1},
pages={365-374},
abstract={It is well known that diversity performance of communication systems using signals with high dimensions in time, frequency and/or spatial domains depends on correlation of the channel characteristics along signal dimensions. On the other hand, it has not been payed due attention how the coherent receiver which combines the signals is greatly affected by the erroneous channel estimation which can undermine the diversity gain. In this paper, assuming that the estimator is given the a priori probability of the channel characteristics, we propose an optimum estimation scheme based on MAP criterion, in an uplink-MC/CDMA system on channels with frequency selective fading, with an array of antennas at the receiver. The MAP estimator effectively takes into account the correlation of the channel characteristics that the conventional estimator neglects. We also propose a signal design in pilot symbol periods that enables the receiver to separately obtain the sufficient statistic for estimating the channel characteristics without MAI. Using computer simulation, we obtained MSE error performances of the proposed estimator compared with the conventional estimator and their effect on BER performances of the diversity combining receiver. It was observed that using the conventional estimator for combining greater number of signals than the effective channel dimension deteriorated the BER performance while using the proposed estimator kept the optimum performance just as the error-free estimator did. Also obtained for MC/CDMA systems are BER performances of the single user matched filter and MMSE receivers using the proposed and the conventional estimators. A considerable improvement of the MMSE performance was achieved owing to the optimum estimator. It remains for the a priori probability of the channel characteristics to be properly assumed and dealt with in sequential estimation.},
keywords={},
doi={},
ISSN={},
month={January},}

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TY - JOUR
TI - The Optimum Channel Estimation for Coherent Receivers in Multicarrier CDMA System with Antenna Array
T2 - IEICE TRANSACTIONS on Communications
SP - 365
EP - 374
AU - Masahiro FUJII
AU - Rie SHIMIZU
AU - Makoto ITAMI
AU - Kohji ITOH
PY - 2003
DO -
JO - IEICE TRANSACTIONS on Communications
SN -
VL - E86-B
IS - 1
JA - IEICE TRANSACTIONS on Communications
Y1 - January 2003
AB - It is well known that diversity performance of communication systems using signals with high dimensions in time, frequency and/or spatial domains depends on correlation of the channel characteristics along signal dimensions. On the other hand, it has not been payed due attention how the coherent receiver which combines the signals is greatly affected by the erroneous channel estimation which can undermine the diversity gain. In this paper, assuming that the estimator is given the a priori probability of the channel characteristics, we propose an optimum estimation scheme based on MAP criterion, in an uplink-MC/CDMA system on channels with frequency selective fading, with an array of antennas at the receiver. The MAP estimator effectively takes into account the correlation of the channel characteristics that the conventional estimator neglects. We also propose a signal design in pilot symbol periods that enables the receiver to separately obtain the sufficient statistic for estimating the channel characteristics without MAI. Using computer simulation, we obtained MSE error performances of the proposed estimator compared with the conventional estimator and their effect on BER performances of the diversity combining receiver. It was observed that using the conventional estimator for combining greater number of signals than the effective channel dimension deteriorated the BER performance while using the proposed estimator kept the optimum performance just as the error-free estimator did. Also obtained for MC/CDMA systems are BER performances of the single user matched filter and MMSE receivers using the proposed and the conventional estimators. A considerable improvement of the MMSE performance was achieved owing to the optimum estimator. It remains for the a priori probability of the channel characteristics to be properly assumed and dealt with in sequential estimation.
ER -