Hybrid µGA based optimum detectors for OFDM system

When the cyclic prefix is less than channel memory or under clipping noise in Orthogonal Frequency Division Multiplexing (OFDM) detection, a good Bit Error Rate (BER) performance is achieved using the Maximum Likelihood Block Detector (MLBD). However, the computational load at the receiver is high under this condition. It is well known that conventional GA based approach offers less computation for MLBD. In this paper, a Hybrid μGA based MLBD for IEEE 802.11a Wireless Local Area Network (LAN) modem is proposed. The new system offers reduction in computational load as compared to the conventional GA based approach without any performance deviation. This will enable consumers to use high data rate receiver by choosing a higher modulation scheme at low Signal-To-Noise-Ratio (SNR) under the above mentioned severe conditions. Simulation results show that the BER performance is the same as the conventional GA based system. Complexity analysis reveals that at 20dB channel SNR, the scheme executes five thousand functions evaluation only. Whereas, the GA based approach executes 50 thousand objective functions evaluation.