Antenna switching scheme for downlink time switched transmit diversity with ARQ in the WCDMA LCR-TDD system

In this paper, the antenna switching scheme is proposed for Time Switched Transmit Diversity (TSTD) with ARQ (automatic repeat request) in WCDMA LCR-TDD systems, and the system performances are also investigated. The proposed TSTD system employs the ARQ scheme in which the receiver sends the acknowledgement signal (ACK or NACK) to the transmitter in order to predict the condition of the channel. For the ARQ-aided TSTD system, the proposed antenna switching pattern triggers the transmit antenna switches. Simulation results demonstrate that the performances of the TSTD systems can be improved by applying the ARQ scheme. Furthermore, the performances of ARQ-aided TSTD systems may be significantly improved by applying the proposed antenna switching scheme, especially when the mobile speed is low.