Low complexity pilot-assisted multi-stage parallel interference cancellation under multiple frequency offset in cooperative SFBC-OFDM system

다국어 초록 (Multilingual Abstract)

The inter-carrier interference (ICI) in the presence of the multiple carrier frequency offsets in cooperative SFBC-OFDM system causes to degrade the performance of data detection and is hard to be removed perfectly. In this thesis, a new scheme for cancelling ICI is proposed to achieve a good BER performance comparing to the conventional algorithms. Multi-Stage Parallel Interference Cancellation (MS-PIC) is introduced to enhance the performance of data detection, by using pilot-interferences. Moreover, Decision-aid MRC-like SFBC decoding is applied to MS-PIC in order to reduce the complexity of SFBC decoding, comparing to block ML or block ZF decoding. MS-PIC has a good performance for cancelling ICIs in the presence of the multiple carrier frequency offsets, comparing to the conventional algorithm. Decision-aid MRC-like SFBC decoding has lower complexity than Block ML or Block ZF decoding.
MS-PIC removes the interference induced by the pilot signals with multiple CFOs at first and detects the signals of pilot-adjacent SFBC blocks, because they are more confident than those of the other SFBC block after removing the pilot interference. Decision-aid MRC-like SFBC decoding is a modified scheme of MRC-like SFBC decoding for improving the detection performance, by adding a decision block and compensating a distorted factor.
In this thesis, it is shown by the simulation that MS-PIC algorism improves the BER performance with an approximately 20dB gain at high SNR and Decision-aid MRC-like SFBC decoding reduces the complexity of MS-PIC to 45 percent, comparing to Block ML decoding.