A novel OFDM frame structure for ultra large-zone cell deployments

This paper proposes a novel frame structure for Orthogonal Frequency Division Multiplexing (OFDM) based broadband wireless access and its application. The proposed frame structure, which is robust against inter-symbol interference (ISI) caused by a very large delay spread of multi-paths, is applicable to ultra-large-cell environments where the cell radius is comparable to that for broadcast services without changing key parameters of the OFDM frame such as the guard interval duration and symbol duration, which are optimized for cellular networks. Simulation results show that the proposed method has an advantage compared to the conventional OFDM frame structure when the delay spread is extremely large, i.e., excess delay exceeds the guard interval duration, and the ISI is the dominant factor in degrading the performance.