Abstract
The authors have been researching large capacity transmission technology using 4×4 MIMO scheme to develop SHV wireless cameras. As the number of transmitting antennas increases such as a 4×4 MIMO system, the complexity of signal detection by MLD, which is the best technique to achieve low BER performance, becomes large exponentially. To solve this difficulty, we have proposed the complexity-reduced MLD using Block QR decomposition. In this report, we developed an experimental system of 4×4 MIMO-QPSK demodulator using proposed technique and evaluated the effectiveness of complexity reduction and the BER performance. From the result, we succeeded in developing the 4×4 MIMO-QPSK demodulator which reduces multiplications to 54 % and additions-subtractions to 56 % compared with conventional MLD, achieving the BER performance degraded by 1 dB from the result of computer simulation.
