Further Results on Field Experiments of Coherent Wideband DS-CDMA Mobile Radio

Tomohiro DOHI  Yukihiko OKUMURA  Fumiyuki ADACHI  

IEICE TRANSACTIONS on Communications   Vol.E81-B       pp.1239-1247
Publication Date: 1998/06/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Category: Mobile Communication
DS-CDMA,  mobile radio,  reverse link,  transmit power control,  antenna diversity,  Rake combining,  

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Field experiments using the 2 GHz carrier frequency band were conducted nearby Tokyo to evaluate the effect of joint use of Rake combining and antenna diversity and also the effect of spreading chip rate (or bandwidth) on the achievable bit error rate (BER) performance and the mobile station transmit power distribution of power controlled coherent DS-CDMA reverse-link (mobile-to-base). Four chip rates, 0. 96, 1. 92, 3. 84, and 7. 68 Mcps, were used. The command interval and power step size of the fast transmission power control (TPC) used in the experiments, 1. 25 ms and 1 dB, respectively, were based on measurements of signal-to-interference plus background noise power ratio (SIR) after Rake combining. The field experiments demonstrate that the joint use of antenna diversity and Rake combining significantly improves the BER performance and, furthermore, that increasing the chip rate improves the BER performance and decreases the transmit power because of enhanced Rake combining through an increase in the number of resolved paths.