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| MMSE Iterative Soft Interference Cancellation Algorithm Using Transmit Power Allocation Scheme in V-BLAST System |
| Tang Wan-bin; Zhang Liang; Li Shao-qian |
| National Key Lab. of Communication, University of Electronic Sci.&Tech. of China, Chengdu 610054, China |
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Abstract In an achieving near-capacity V-BLAST turbo receiver, Soft-In/Soft-Out (SISO) signal detector is needed. Minimum Mean Square Error (MMSE) iterative soft interference canceller is a popular SISO detector in such system. Link adaptation is a good scheme to improve performance in wireless system. In the paper, a modification of MMSE iterative soft interference cancellation detector is presented for variable transmission power, and an effective transmit power scheme is proposed to decrease Bit Error Rate (BER). This scheme requires small feedback overhead. By simulation of uncoded V-BLAST system with 4 transmit antennas and 4 receive antennas, it is proved that if the performance requirement of BER=10-3, the modified V-BLAST system with transmit power allocation outperforms the conventional V-BLAST system about 2dB when QPSK modulation is used and iterative number of detection equals 2. When 16QAM is used, the proposed scheme outperforms the conventional scheme about 6dB.
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Received: 17 December 2004
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2006, Vol. 28 
