Correction of sensing imperfections using channel coding in cognitive radio networks while keeping sensing time low

摘要

Spectrum sensing (SS) is the key enabling technology for wideband cognitive radio networks, where two coexisting systems share the same frequency band. The critical task of SS is required to detect spectrum opportunities and to determine if the spectrum allocation meets the quality of service (QoS) requirements of different users. In case of missed detection, collision happens between secondary and primary users. This causes erasures along the secondary user bit stream and a fraction of data is lost. Since the sensing time determines network responsiveness and performance, it is desired to maintain this parameter reduced as possible. But this can be at the expense of increasing collision probability. Thus, the secondary receiver can employ coding to counter the effect of erasures, according to desired sensing time. In this paper, we design new decoding scheme based on BCH codes to compensate for the decrease in sensing time. Simulations were carried out and the results show that our technique exhibits better performance in terms of bit error rate (BER) for high achievable rates, while keeping the sensing time at lower level.