ARQ-Aided Downlink Time Switched Transmit Diversity with Power Ramping in the WCDMA LCR-TDD System

Seung-Hoon HWANG  Cha-Eul JEON  Ri-A MA  

IEICE TRANSACTIONS on Communications   Vol.E93-B   No.2   pp.419-422
Publication Date: 2010/02/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E93.B.419
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Terrestrial Radio Communications
time swithed transmit diversity,  automatic repeat request,  WCDMA,  low chip rate-TDD,  power ramping,  antenna switching,  

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This paper investigates the performance of ARQ-aided downlink Time Switched Transmit Diversity (TSTD) in the WCDMA Low Chip Rate (LCR)-Time Division Duplex (TDD) system, when antenna switching and power ramping are applied. With the help of the ARQ signal, where the receiver sends the acknowledgement (ACK or NACK) to the transmitter, the proposed TSTD scheme switches the transmit antenna and ramps up the transmission power for the retransmitted data, when the transmitter receives a NACK signal. Simulation results demonstrate, that when the mobile speed is 3 km/h and a frame error rate (FER) is set to 1%, the antenna switching scheme yields 2 dB to 3 dB performance gain in terms of average Eb/N0, and the power ramping gives 0.7 dB to 1.6 dB gain, compared with the conventional ARQ-aided TSTD. In addition, 6% of throughput gain is shown by amalgamating the antennas switching as well as the power ramping, when the average Eb/N0 is equal to 0 dB.