Belief-Propagation Based MIMO Detection Algorithm And Its Application

With the rapid development of wireless communication services, the conflict between the finite frequency spectrum and communication capacity has been getting more and more serious. In this condition, how to increase the spectrum efficiency has been a hot topic for a long time. Recently, it is shown that MIMO technology is an effective technology to break through the capacity limit of SISO systems in fading channel without additional bandwidth and transmitting power consumption. Research on belief-propagation based detection algorithm in MIMO and its application and available performance in different MIMO systems is the primary objective of this thesis. The fundamental is as follows. In the transmitter side, the multiple-antenna transmission in the MIMO system will incur temporal and spatial dependency via the space-time coding technique. In the receiver side, the unified BP detector is employed based on the inherent correlation relationship imposed by the space-time coding scheme.Based on analysis and verification of BP algorithm as the detection scheme of space-time code, the thesis investigate the program and applicability of BP algorithm in different space-time coding technology, especially in BLAST and QSTBC. It analyzes the complexity of MIMO detection technology based on BP algorithm and factors which can influence the detection performance. The simulation results show that BP algorithm is viable to detect MIMO system and can provide excellent performance.PSTBC is a kind of special block space-time code which has full rate, good shaping(QAM or HEX) and full diversity. Its minimum determinant is non zero and it has uniform average transmitted energy per antenna in all time slots. Based on the construction of the PSTBC, the thesis discusses BP algorithm available to PSTBC detection. The simulation results show after the equivalent construct transformation from PSTBC to VBLAST, that BP algorithm is viable algorithm for PSTBC detection and can provide excellent detection performance.The wireless communication system in society generally uses the channel coding technology. The thesis analyses the MIMO system detection technology which use LDPC and verifies that circular detection and decoding algorithm based on BP algorithm can provide the excellent performance.It is concluded that, for perfect channel estimate MIMO system, BP algorithm can provide good detection performance with acceptable complexity and is a near optimal detection algorithm. Furthermore, BP algorithm is viable for different MIMO detection to achieve the reasonable performance and it has the universality in different MIMO systems detection.