In this paper, we consider double space time transmit diversity (D-STTD) with an adaptive modulation (AM) algorithm. The simple criteria to use AM algorithm and antenna shuffling pattern are proposed according to linear receivers such as zero-forcing and minimum mean square error receiver. The AM algorithms are derived to minimize bit error rate (BER) under the fixed total data rate and total transmit power. The D-STTD system using the proposed algorithms requires low computational complexity and small feedback information bits. The performance of D-STTD system using the proposed algorithm is improved by about 5.8 dB or more in signal to noise ratio (SNR) corresponding to 10 -3  BER. Additionally, using antenna shuffling, BER performance is more improved, but more feedback information bits are also required.
['Jaesang Ham', 'Kyeongyeon Kim', 'Seijoon Shim', 'Chungyong Lee']
An Efficient Adaptive Modulation Algorithm for D-STTD System