Selection combining technique and its real-time FPGA implementation for spectrum sensing efficiency improvement in cognitive radio

Abstract

Reception diversity has considered as an effective way to improve the system performance. In this paper, we present a real-time hardware implementation of spectrum sensing based energy detection (ED) with multi-receive antenna technique. We only focused on Selection Combining (SC) technique due to low complexity in Radio Frequency (RF) chain (need only one RF chain). The system performance is evaluated in real-time hardware implementation over Rayleigh environment based FPGA (Field Programmable Gate Array) platform. The DVB-T (Digital Video Broadcasting - Terrestrial) signal is designed as primary signal. This is specified in draft IEEE 802.22 WRAN standard for re-utilization the TV frequency band. The target FPGA board is Stratix II EP2S180. The fixed point 32 bits (fraction: 22.10) is chosen for calculation in FPGA model. The empirical results showed that the performance of ED with selection combining technique was improved remarkably. Thus, we conclude that selection combining techniques can be used to overcome the drawbacks of ED over Rayleigh fading environment. © Springer-Verlag Berlin Heidelberg 2014.