Abstract
Mobile WiMAX, IEEE 802.16m, is widely used for high-speed internet access. It is based on the cyclic prefix OFDMA (CP-OFDMA) technique, employing many pilots. Utilizing a large number of pilots increase the pilot overhead and reduce the data rate and spectral efficiency of a mobile WiMAX system. This paper proposes the incorporation of time–frequency training OFDMA (TFT-OFDMA) symbol with an optimum number of pilots. The proposed technique embeds a different density of pilot subcarriers and employs a compressive sampling-based channel estimation technique. This paper compares Mobile WiMAX's BER performance for different densities of pilot subcarriers for vehicular speed upto 350 km/h. System performance is analyzed in terms of pilot overhead. Simulation results demonstrate that reducing the number of pilots compared to the pilots used in the legacy WiMAX system gives a comparable bit error rate (BER) performance for low vehicular speed. Employing an optimum number of pilots reduces the pilot overhead by 5.5% and 4.17% for type II and type III pilot density, respectively.
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