Performance Improvement of OFDM-Based Cognitive Radio System

Efficient use of available spectrum is an important criteria for communication systems which can be fulfilled using Cognitive Radio (CR). In this paper, we focus on bit allocation and windowing for performance improvement of OFDM based CR. We consider two different bit allocations namely, variable and adaptive. The Bit Error Rate (BER) analysis without windowing shows that the adaptive method performs better since the bit allocation is varied according to the varying Signal to Noise Ratio (SNR). To improve the BER performance further, various windowing techniques are analyzed. The results show that Hamming and Kaiser Windows offer reduced error rate compared to Hanning window when used with adaptive bit allocation.