Analysis of CSIR for an OFDM System Limited by a Frequency-Hopping Interferer

This thesis explores an OFDM communication system in the presence of a unsophisticated frequency-hopping interferer. Information theory is used to explore the fundamental limits of system performance with varying degrees of knowledge about the state of the interferer. In particular, the Shannon channel capacity of the system is derived for two different cases of channel state information at the receiver (CSIR), namely Perfect CSIR and Partial CSIR. An approximation of the Shannon channel capacity via Monte Carlo techniques is also made for the case of No CSIR for comparison. The gains in signal-to-noise ratio (SNR) obtained by Partial and Perfect CSIR for various interference powers are considered. The results show a trade-off between computational complexity and the gains in SNR.

Next, practical implementations of the system that approach the channel capacity are explored. The bit error rate (BER) of these systems is simulated as a function of SNR with various interference powers. Finally, an analysis is performed to compare the BER of the practical systems against the theoretic channel capacities found earlier. The results indicate that a practical system can obtain gains similar to those found from information theory.