![]() | Only 14 pages are availabe for public view |
Abstract Muhammad Ismail Muhammad, ”Performance Evaluation of OFDM System Subjected to Frequency Offset in General Fading Channels”, Master of Science dissertation, Ain Shams University, 2009 Orthogonal frequency division multiplexing (OFDM) is a multicarrier transmission technique that has been recently recognized as an excellent method for high speed bi-directional wireless communications. It provides a good performance against the most severe multi-path propagation conditions. OFDM is sensitive to frequency synchronization errors, which results in inter-carrier interference (ICI) and degrades system’s performance. This research work aims to investigate the combined effects of carrier frequency offset (CFO) and fading conditions on system’s performance. Nakagami-m fading channel is used as a multi-path propagation model for its ability to emulate fading channels whose conditions are either less severe than, the same as, or more severe than the Rayleigh fading model. Closed form expressions of BER/SER for OFDM system subjected to CFO over Nakagami-m fading channel are developed. The impact of CFO and severe fading conditions on performance is revealed. CFO mitigation techniques are introduced to improve system’s performance when subjected to CFO. Closed form BER/SER expressions are developed for polynomial cancelation coding (PCC)- OFDM and the ameliorated ICI cancelation OFDM when subjected to CFO in Nakagami-m fading channel, and system improvement is emphasized. To combat the severe fading conditions, diversity reception is applied. Space diversity reception is employed at the receiver and maximum ratio combining (MRC) is used. The effect of correlation among diversity branches is considered. Expressions of BER/SER for PCC-OFDM subjected to CFO with diversity reception over Nakagami-m fading channel are developed, and in some cases expressions result in a closed form. |