Research And Realization Of Cognitive Gateway Based On GNU Radio And USRP

Due to the fixed radio spectrum allocation policy, the utilization of spectrum resourceshas low efficiency. Also, more and more people pay attention to the compatibility issuescaused by the rapid development of communication technology. Cognitive Radio (CR)technology is introduced into heterogeneous wireless networks, and the concept of CognitiveGateway (CGW) is proposed to enable the interconnection and interworking in heterogeneousnetworks. With CR, unlicensed users could dynamically access to the available idle spectrumwithout interfering licensed users’ regular communications. As a consequence, the spectrumresource is utilized in a much more efficient way. CGW could be viewed as a ‘bridge’ toconnect multiple heterogeneous networks. In these heterogeneous networks, different wirelessnodes operate in different frequency bands, or use different communications standards. Due tothe heterogeneity, different types of nodes can’t communicate with each other directly. CGWfunctions as a router to provide transmission paths among different nodes. Therefore, CGW isdefinitely a promising solution for the interconnection of heterogeneous wireless networks.GNU Radio and USRP constitute a PC-based open source software defined radio (SDR)platform. It is low-cost, easy to use and flexible to reconfigure, which is an ideal platform forCG. Principle and process of GNU Radio is introduced and USRP is described in detail. CG isresearched on the basis of this platform, and architecture of CG is proposed based on “SourceNode-CG-Destination Node” model. A complete CG is composed primarily of five modules:request identification, scenario analysis, decision making, link control and networktransformation. Static and dynamic identification are proposed in request identification.Energy detection and compressed sensing provide two methods for scenario analysis, andcompressed sensing algorithm is simulated to evaluate the performance. Decision making andlink control are two important components in CG to achieve interoperability. Classification ofnetwork transformation is presented and realization of each classification is provided based onSDR platform. ZigBee protocol is realized on this platform. Network transformation of CG isvalidated in three scenarios of heterogeneous network.