OFDM synchronization mechanisms with robustness against jamming

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Orthogonal Frequency Division Multiplexing (OFDM) has been selected as the physical layer modulation technique for fourth generation wireless communication systems due to its high spectral efficiency. OFDM has the ability to combat severe multipath fading by transmitting overlapping yet orthogonal subcarriers that can be easily demodulated at the receiver. However, OFDM is very sensitive to synchronization errors, sampling and carrier frequency offsets, Radio Frequency (RF) saturation effects, and other mismatches that occur due to the non-ideal characteristics of various RF circuits. The presence of such mismatches leads to inter-carrier interference and can cause severe degradation in the system performance. In this project, we will focus on mitigating the effects of smart jammers on the synchronization and RF mismatches estimation and compensation algorithms for OFDM systems. We will study the effects of different types of smart jamming signals on OFDM systems and evaluate the performance of classical algorithms in the presence of jamming. We will utilize the results of this study in identifying hostile jamming situations by monitoring the performance of the synchronization loops and the RF mismatches estimation blocks. We will consider two types of jamming signals; non-intentional friendly jamming (interference) and hostile jamming. In the first case, we will design interference co-ordination and power control algorithms to prevent performance degradation of OFDM system. On the other hand, when co-ordination is not possible, for example due to the hostility of the jammer, we will design cognitive and robust synchronization and RF mismatches mitigation algorithms than can maintain acceptable performance of the system and prevent its catastrophic failure.