Mapping for Iterative MMSE-SIC with Belief Propagation

Abstract— In Multiple-Input Multiple-Output (MIMO) wireless systems, since different signals are transmitted by different antennas simultaneously, interference occurs between the transmitted signals. The receiver has to detect each signal from the multiplexed signal. MMSE-SIC combines MMSE filtering and Soft Interference Cancellation (SIC) with soft replicas and can achieve good Bit Error Rate (BER) performance. If an irregular LDPC code or a turbo code is used, the reliability and BER of the information bits output by the decoder are likely to be higher and better than the parity bits. In MMSE-SIC, bits with poor reliability lower the accuracy of soft replica estimation. When the soft replica is inaccurate, the gain obtained by SIC is small. For M-ary Phase Shift Keying (PSK) and M-ary Quadrature Amplitude Modulation (QAM), larger constellations such as 8PSK and 16QAM transfer more bits per symbol, and the number of bits per symbol impacts the accuracy of SIC. Unfortunately, increa...

• Type: Conference
• Year: 2007
• Where: ICC
• Authors: Satoshi Gounai, Tomoaki Ohtsuki
• Keywords: Communications, ICC 2007, Information Bits, Protected Bits, Soft Replica