Decision Feedback Equalization for ALAMOUTI-Coded Cooperative OFDM Systems with Insufficient Cyclic Prefix
Sa Yang · Journal of Nanjing University of Posts and Telecommunications · 2014
In the ALAMOUTI-coded cooperative communication system,an orthogonal frequency division multiplexing( OFDM) technology is used to combat the time delay from relay nodes to the destination, which can be treated as a multipath channel. The inter-symbol interference( ISI) resulting from the time delay,however,cannot be completely eliminated if the length of cyclic prefix( CP) is less than that of the relay time-delay. To solve this problem,a decision feedback equalizer( DFE) is introduced into the ALAMOUTI-coded cooperative OFDM system with insufficient length of CP. Two equalizers are designed based on zero forcing( ZF) criterion and minimum mean square error( MMSE) criterion. Simulation results show that both equalizers can improve the system performance,and the equalizer with MMSE-DFE criterion has optimal performance.