Prototyping and performance evaluation of TDD-based 2×2 MIMO-OFDM transceiver

We have been developing a new wireless link that enables quick transmission of file-based video resources for news programmes. Since the transmission distance we assume ranges widely from less than 1 km to as far as 50 km, it is necessary to have efficient transmission timing control in duplex communication based on TDD. In order to enhance the transmission capacity in line-of-sight environments, it is useful to introduce a MIMO technique that exploits dual-polarized antennas and a multilevel modulation scheme such as 128 QAM and 256 QAM. In this paper, we describe the prototype TDD-based 2×2 MIMO-OFDM transceiver and its performance evaluation in wired and radio transmission experiments.