Design and Performance Evaluation of Signaling Link Demodulator for PCP-OFDM System

An adaptive orthogonal frequency division multiplexing (OFDM) system, with a preceded cyclic prefix (PCP) as a signaling link was proposed earlier to address the recent need of flexible transmission techniques in cognitive radio (CR) communications. The flexibility of the PCP-OFDM system relies on the concurrent transmission of OFDM signal and PCP signaling which represents OFDM system parameters including bandwidth, modulation, coding schemes etc. Efficient demodulation of PCP signaling is therefore of great importance for OFDM data recovery and reduce the delay from the system adaption. In this paper, we propose to use a three-stage demodulator to recover the signaling information carried by the PCPs. Design of this three-stage demodulator are analyzed and performance is evaluated through the simulations in different channel conditions. In addition, with proposed peak combining technique, impact of the multipath impairment is mitigated to a great extent. It is observed from the simulation results that this signaling demodulation scheme provides the same performance as the conventional optimal matched filter but with significantly reduced hardware and computational complexity.