Multi-channel MAC Protocol Design In Cognitive Ad Hoc Network With Heterogeneous Spectrum

Cognitive ad hoc network introduces the cognitive radio technology intoad hoc network, it is not only improving the traditional wireless ad hoc network’s ability to adapt to the complex electromagnetic environment, but alsobring some new challenges about spectrum control technology in ad hoc network. As the key technology of the cognitive ad hoc network data link layer protocol, media access control(MAC) protocol is responsible for spectrum sensing, spectrum allocation, spectrumsharing and spectrum access of the cognitive nodes. On the premise of not affecting authorized user communication, it coordinate the access to the physical layer orderlyof all SU nodes, so it can improve the utilizationof limited spectrum resources effectively. To achieve this, Thisthesisaim at reducing the interference to the primary user networkand improving the channel utilization of cognitive nodes.It design two MAC protocol with a single control channel and multi-control channel respectively in heterogeneous spectrum environment, using the distributed network strategy in multi-hop multi-channel cognitive ad hoc network, and use the simulation software to verify at the same time. At first, this thesisanalyse two kinds of existing single control channel multi-hop cognitive MAC protocol, which are based on collaboration sensing, and compare their network performance through simulation on OPNET Modeler platform. Through the simulation results, it can be seen that MMAC-CR protocol use the multi-channel MAC protocol design criteria based on the split phaseand collaborative sensing fusion mechanism based on busy signal transmitting. The former will lead toa long time interference on the primary user communication, and the laterwill lead to higher collaborative sensing false alarm and miss detection errors.While DCC-MAC protocol is based on dedicated control channel of multi-channel MAC protocol design criteriaand enhanced collaborative sensing mechanism, and through using data transmission channel in time and collaboration sensing, it can achieve the better protection of primary user communication and the more utilization of theidle spectrum.Secondly, in view of the poor performance of the above DCC-MAC protocol in the large scale network and the large channel number condition, Thisthesis further designa distributed collaborative sensing algorithm based on the communicating node, and based on this algorithm it proposed a multi-hop cognitive MAC protocol with a single control channel, namely the SCD-MAC protocol. Through the simulation result, it can seen that compared with DCC-MAC protocol, SCD-MAC protocol effectively improve the efficiency of distributed collaborative sensing and control information interaction, and reduce the time consumption of sensinginformation interaction. So, it acheive the shorter interference to primary user and higher throughput of network data transmission.Finally, this thesis willfurther expand the design idea of SCD-MAC protocol to multi-control channel multi-hop ad hoc network, so it can further solve the single control channel saturation problem of single control channel MAC protocol. Through the introduction of collaborative sensing mechanism under the control channel, the paper designed MCD-MAC protocol based on multi-control channel can effectively overcome the deafness problems of theexisting multi-control channelcognitive MAC protocols. Through simulation it can be seen that the MCD-MAC protocol not only alleviate the single control channel saturation bottleneck, but also can effectively reduce the interference of cognitive ad hoc network to primary user communication.