||This thesis investigates on channel estimation and equalization in the Orthogonal Frequency division Multiple (OFDM) mode of the IEEE 802.16 standard. OFDM systems exhibit superior characteristics with simplicity in combating multi-path transmission and have efficiency in spectral utilization. The effects of ICI and ISI arise from the multi-path interference could be successfully eliminated by the insertion of cyclic-prefix. Furthermore, the advantage of spectral efficiency is achieved by the orthogonal property. Under the protection of cyclic-prefix, multi-path effect causes distortion of amplitude and phase only. In accordance with the exact channel estimation among sub-carriers, the distortion could be compensated by one-tap complex coefficients.|
With the consideration of hardware implementation, the algorithms of the channel estimation and equalization are investigated and simulated for static channels for IEEE 802.16 systems. Moreover, the dependence of the receiving performance upon relationships between channel conditions and system specifications, e.g. transmission band, bandwidth, sub-carrier spacing, etc. would be clarified from simulation results. In the receiver, channel frequency response is obtained by utilizing a least square method, and we use an interpolation method to get channel frequency response of subchannels. We implement the schemes with the Verilog language and verify the function of modules with the ModelSim software.
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