Doppler Reduction Effect on the Performance of IEEE 802.11a Based on Sub-Frequency Band Algorithm

Over the last decade, the development of IEEE 802.11a which referred to as Local Area Network (LAN) standard is rapidly advancing. This is due to the limitation and what Orthogonal Frequency Division Multiplexing (OFDM), which is used in the heart of LAN standard, susceptible to like carrier frequency offset and hence higher Bits Error Rate (BER). In this paper, the performance of IEEE 802.11a based on a subfrequency band algorithm was investigated and tested over Additive White Gaussian Noise and Rician channels and under different Doppler frequency effects. The proposed system was investigated over the physical layer of IEEE 802.11a. Within the transmitter, the data vector of 64-bits is divided into three equal vectors of 21 bits each, with the last bit discarded. Each vector was then processed by fast Fourier transform block, with the output of each block processed by a proposed algorithm and then the total vector of length 64-bits converted to a time domain signal via the inverse fast Fourier transform. Within the receiver, the inverse procedure is used to recover the transmitted signals. The results show that the proposed algorithm outperforms the standard OFDM model in terms of Bit Error Rate (BER) versus Signal to Noise Ratio (SNR). Index Term-OFDM Orthogonal Frequency Division Multiplex, IEEE 802.11a LAN, BER Bit Error Rate, SNR Signal to Noise Ration, Fast Fourier Transform FFT, IFFT.