Radio Implementation of a Testbed For Cognitive Radio Source Localization Using USRPS and GNU Radio.

摘要

The shift from wired to fully wireless communication is causing an increasing demand on the frequency spectrum. The cognitive radio was introduced to solve spectrum scarcity by allowing spectrum sharing between licensed and unlicensed users. This approach presents a challenge to source localization because of the cognitive radio's capability to shift its spatial, frequency and temporal parameters. The extended semi-range-based (ESRB) and cooperative-received-signal-strength-based (CRSSB) localization schemes are proposed to overcome the challenge of identifying and locating a cognitive radio over time using a wireless sensor network. The objective of this thesis was to set up a testbed using GNU Radio and Universal Software Radio Peripherals (USRPs) to estimate the position of a cognitive radio device using the ESRB and CRSSB localization schemes. The ESRB algorithm does not provide accurate position estimates but the estimates are observed to be concentrated in the vicinity and converging toward the true position of the secondary user. The errors are believed to be caused by three factors: a limited number of sensor nodes used (four), an insufficient number of spectral scans per superframe (55), and the lack of synchronization among sensor nodes. The CRSSB localization scheme gave a more accurate position estimation.