Robust Lp-norm metric for BICM-OFDM cognitive radio systems

Cognitive radio (CR) systems make efficient use of the frequency spectrum by opportunistically exploiting unoccupied or under–utilized frequency bands. However, the frequency bands used by CR systems are expected to suffer from various forms of noise and interference with non–Gaussian distributions, such as narrowband and co–channel interference caused by the primary user and other CRs, respectively, and man–made impulsive noise. To mitigate the harmful effects of non–Gaussian noise and interference, we propose a robust Lp–norm metric for CR systems that employ the popular combination of bit– interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). For the considered CR system we provide an approximate upper bound and an asymptotic closed–form approximation for the bit error rate (BER). Our results show that the proposed Lp–norm metric can achieve large performance gains compared to the conventional L2–norm metric in non–Gaussian noise and interference.