Performance of Feedback-Type Adaptive Array Antenna in FDD System with Rake Receiver

Mona SHOKAIR  Yoshihiko AKAIWA  

IEICE TRANSACTIONS on Communications   Vol.E89-B   No.2   pp.539-544
Publication Date: 2006/02/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.2.539
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
feedback-type adaptive array antenna,  frequency division duplexed,  rake receiver,  

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The performance of a feedback-type adaptive array antenna (AAA) system placed only at a base station (BS) in an FDD/DS-CDMA system remains insufficiently clear. We evaluate the performance of this system by considering the effect of a rake receiver, spacing distance between antennas, the maximum Doppler frequency (fd), and control delay time (Td) on BER performance. In this system, the mobile station (MS) determines optimum weights of antenna elements and sends them back to BS as feedback information. We assume that the optimum weights are not quantized. Thereby, we estimate the performance degradation of 3GPP transmit diversity system, where the feedback information is quantized using a few bits. Computer simulation results show that the rake receiver achieves better BER performance because of the time diversity effect with rake receiver. The AAA with a wide antenna spacing gives high diversity gain for the received signals. For a high value of fd Td, BER performance becomes worse because weighting factors cannot follow the changing speed of channel characteristics. The degradation in performance of a 3GPP system is clarified.