Design and Implementation of Efficient Beamforming Transmitter in OFDMA/TDD System

This paper presents the efficient structure and parameter optimization of downlink beamforming transmitter in OFDMA/TDD system. To design downlink beamforming transmitter for multiple transmit antennas, an efficient beamforming structure for multiple users and the choice of word-length of main data path are critical in the aspect of its performance and hardware complexity. We propose an efficient beamforming scheme, which calculates the weights for corresponding user in a subcarrier unit of IFFT input at high speed to reduce the hardware complexity and processing time of transmitter and receiver. Also, we obtain the word-length of main data path and other design parameters by simulation analysis. The proposed architecture could reduce the memory size proportional to the maximum number of users per frame, and the processing time of an OFDM symbol at the receiver of base station without the need of an additional processing time for calculating the weights at the transmitter.