|M.Sc Student||Lior Davidovitch|
|Subject||Performance of Mobile Communication System Using OFDM|
|Department||Department of Electrical Engineering||Supervisor||Mr. Kalet Yitzhak|
This thesis deals with three basic issues which affect the performance of mobile OFDM communication systems.
The main subject of this work, is the influence of different pilot patterns in OFDM systems which use pilot symbol assisted modulations (PSAM). The research also includes the performance of OFDM systems using pre-compensation, and the effect of the number of sub-channels used in OFDM systems on the minimization of the bit error rate.
Pilot symbols are used to perform reliable channel estimates. The effect of four different pilot patterns on bit error rate are investigated. A description of an algorithm for the design of suitable pilot estimation pattern is given. We found the best pilot pattern to use, amongst four patterns tested.
We also investigated the use of pre-compensation in the base station in order to improve the performance of OFDM systems. Different methods in which amplitude and/or phase are adjusted, are analyzed in terms of performance limits. Phase-only compensation is preferred at low SNR ratio, while at high SNR ratio an order of magnitude improvement in the BER can be obtained by including amplitude pre-compensation.