Fractional Bandwidth Mode Detection and Synchronization for OFDM-Based Cognitive Radio Systems

For the CR systems sharing the spectrum with narrowband primary devices, this paper presents an OFDM system supporting the fractional bandwidth (FBW) mode to avoid the interference to or from the primary devices. For the system, the preamble and FBW mode detection algorithm are provided to obtain the FBW mode information during the initial synchronization. The simulation results reveal that the FBW mode information can be obtained at the SNR region lower than E_s/N0 = 0 dB. In addition, the FBW mode transmission and detection do not incur any deterioration of the synchronization performance.