MIMO-OFDM equaliser for spatial multiplexing transmission modes

[摘要] In search for faster and more reliable communication, multiple-input multiple-output (MIMO) inconjuction with Orthogonal Frequency Division Multiplexing (OFDM) are subject of extensive research.In spatial multiplexing transmission an instantaneous rise of data rates governed by the number oftransmit antennas can be realised. The system performancedepends highly on signal-to-interference-plus-noise ratios (SINR) at the receiver. The receiver'sequaliser is supposed to maximize the SINR by mitigating the spatial interference and thusseparating the transmitted signals. For this problem several solutions exist such as linear andnonlinear, per subcarrieror OFDM symbol-based. An overview of common algorithms is given and complexity is discussed. Biterror rate (BER) performance evaluations are presented.Another aspect is the impact of the equalisation strategy on the performance of bit-interleaved softinformation-based channel coding schemes. As a representative, LDPC codes are chosen. Simulationresults show a significant BER performance loss for symbol decision-based equalisers compared to theuncoded performance. To overcome this problem a modification of the Maximum Likelihood algorithm isproposed which yields good performance for low SNR applications.

[学科分类] 电子、光学、磁材料