The application of Smart Antennas in TD-SCDMA

In this paper, the application of smart antennas (SA) in TD-SCDMA is discussed. Generally, people consider that the SA have the SDMA (space division multiple access) effect, based on which the directional beamforming of transmission/receiving can be achieved. That is to say, in TD-SCDMA, on single carrier, simultaneous directional receiving/transmitting is expected to be achieved by using a set of SA. And in order to achieve the simultaneous directional receiving/transmitting, the amplitude-weighting technology of receiving/transmitting baseband signal can be adopted. The two characteristic come from transceiver reciprocity. However, in CDMA, the reciprocity can not be applied unconditionally. For the receiving, the independent directional multi-beamforming can be achieved, by the weight method of carrier or baseband signals. However, as to transmission, the simultaneous directional independent multi-beamforming of multiple CDMA users could not be achieved on single carrier. Therefore, it is better to study carefully whether the SA can work well in TD-SCDMA. In order to take good use of SA in TD-SCDMA standard, we also proposed a high-speed data transmission CDMA/TDMA reform schema about the use of SA in TD-SCDMA.