Hardware-Efficient and Wide-Band Frequency-Domain Energy Detector for Cognitive-Radio Wireless Network

摘要

Cognitive radio is an innovative technology that possesses profound potential to mitigate spectrum scarcity in the next-generation wireless networks. In this technology, unlicensed users are capable of accessing unused portions of the spectrum, popularly known as white spaces, for communication that enhances that spectrum usage. Each of these unlicensed user nodes must incorporate spectrum sensor to detect white space for transmitting and receiving the information. Such spectrum sensors must be portable and it needs to support wide bandwidth suitable for contemporary wireless networks. This paper presents a new frequency-domain energy-detector for spectrum sensing that is hardware efficient. We propose VLSI architecture for this detector where the area and power consuming FFT unit has been replaced by an iterative FFT-computation unit with simple architecture. This area-efficient design also improves the performance of detector in real-world noisy environment. In addition, we extend the conventional single-band detection-approach to a wide-band detection approach and present its VLSI architecture. Performance analysis of such detection in AWGN channel environment showed that the detection probability of 0.16 is achieved at a SNR of -20 dB. Hardware implementation of the proposed energy detectoris carried out using FPGA and its real world testing plus verification is performed using USRP software-defined radio-platform. It could operate with the bandwidth as high as 150MHz with a sensing time of 7 ms. Compared to the state-of-the-art implementation, our prototype consumes 46% lesser hardware resources and does not require any memory in its architecture.