3. Synchronization Frame Design for NBI Mitigation

Synchronization has an important impact on the system performance of broadband communication systems. In particular, OFDM systems are very sensitive to the accuracy of synchronization. In the presence of narrowband interference, the performance of frame synchronization and carrier synchronization is severely influenced. The conventional synchronization frame structure and synchronization algorithms are not designed for mitigating the narrowband interference, resulting in serious performance loss of synchronization in the presence of narrowband interference. Hence, the problem of accurate and efficient synchronization in the presence of narrowband interference is the first utmost important problem to be solved to improve the system performance of broadband communication systems. In this chapter, the design of the OFDM preamble synchronization frame structure for effective narrowband interference mitigation is devised. Efficient and robust algorithms of receiver side frame synchronization and carrier recovery are studied. Besides, the method of frame header signalling transmission robust to the narrowband interference is investigated. Through these studies, the disadvantage of the conventional synchronization methods is overcome, and the synchronization performance of the OFDM system in the presence of narrowband interference is guaranteed. This research will provide basis technical support for the improvement of the overall system performance of the broadband communication systems in the presence of narrowband interference, and provide performance guarantee in the perspective of synchronization for the research of this thesis.