Low cost, faster detection of cognitive radio through filter banks with bandpass sampling

Abstract

In cognitive radio communication systems, fast and reliable detection of the idle channels which are not occupied by the primary users is the most fundamental requirement. In this paper, we first review some of the classical designs of cognitive radio receiver architectures and then propose a new solution using filter banks with the bandpass sampling technique. In conventional heterodyne receiver, a low rate analog to digital convertor (ADC) is used, which contains an analog bandpass filter. This results in a barrier in lowering detection time as significant time is used in the scanning operation. While the homodyne receiver has the capability of fast detection due to the use of high rate ADC, this is an unfeasible or very costly approach. Compressive sensing based receiver architectures are proposed in recent years, however those receivers do not work efficiently under the condition when the spectrum is congested and the number of channels are increased. In this work, we propose a filter banks based receiver with bandpass sampling architecture capable of fast detection and using a low rate ADC as well. In addition, comparative analysis of classical designs and the proposed architecture is carried out by considering performance parameters of detection time, signal to noise ratio and complexity of the receivers.