A Guard Band Decision Algorithm Based on Information of Spectrum Masks for OFDM-Based CR Systems

In the cognitive radio (CR) systems supporting multiple wireless services, the performance of a communication system can be significantly degraded by an adjacent channel interference (ACI) from a neighbor wireless system located in the adjacent channel. A guard band (GB) is generally used to avoid the ACI, but its bandwidth is carefully decided for efficient usage of spectrum. Furthermore, an adjustable GB instead of the conventional fixed GB can be a more effective scheme since the services in the adjacent channel can be frequently changed in the CR systems. In this paper, a practically adjustable GB decision algorithm based on the information of spectrum masks is proposed for the Orthogonal frequency division multiplexing-based CR systems. The spectrum splatter from the neighbor system is analyzed and the proposed scheme is derived with the analytic results and the inverse closed-form of well-known theoretical BER performance. The effectiveness of proposed algorithm is verified by simulation results.