The Research Of Cognitive Radio Testbed Based On GNU Radio And USRP

The ever growing demand for wireless services has placed enormous burden on valuable resources such as spectral bandwidth. This has resulted in a major rethinking in resource allocation policies culminating in an explosion of research activity in the field of Cognitive Radio (CR) towards optimum resource usage.For now there are two way for dynamic spectrum access. The first one is using the ISF band such as2.4GHz Wlan or IEEE802.16h/g. Another one such as IEEE802.22 enables opportunistic use of the radio-frequency spectrum, allowing unlicensed users to utilize licensed bands under the condition that they interfere as little as possible with the licensees. Acognitive radio transmits on bands detected as being free, leaving them whenever a primary user is sensed. For now the researches for CR are mostly about simulating or theory,but lack of research about testbed for test and verification.This work focuses on the practical implementation of a cognitive radio based on GNU Radio and USRP. GNU Radio and USRP make a free software radiotestbed with PCs. This testbed can make the design flexibly and fast. The testbed uses dynamic spectrum access to to utilize licensed bands 400M-430MHz under the condition that they interfere as little as possible with the licensees. A power detector is chosen to sense the spectrum. This thesis presents the function how GNU Radio run and principle of coding. And it presents the structure and function of USRP the hardware mate with GNU Radio. This thesis focuses on the realization of Cognitive Radio based on the testbed such as: reseach large scale spectrum sensing and found out the free band to make decision;research the physic layer of dynamic access and transmission; research the realization of MAC, network and application layers; research the demo system and test performance.