The Research Of Cognitive Radio Network MAC Protocol Performance

At present, the wireless communication technology develop rapidly. The problems ofcontradiction between supply and demand loom large. The waste of numerous spectrumresources is becoming increasingly apparent caused by traditional fixed spectrumassignment strategies. It is the main task that how to improve the spectrum efficiency inthe field of wireless communication. thus cognitive radio technology comes into being. themain idea of cognitive radio technology: Through perceiving intelligently the surroundingspectrum, we use the spectrum resources reasonably and improve the spectrum utilizationwithout affecting the authorized users. This article focuses on the cognitive radio networkrandom spectrum access (OSA, Opportunistic Spectrum Access) MAC protocol, throughthe analysis of PU (Primary Users) and SU (Secondary Users) interaction in randomspectrum access protocol. cognitive spectrum access network performance analysis modelis established.First of all, we researched a new mechanism for (OSA) protocol for signal channelbased on IEEE802.11. We model process of cognitive network access withfour-dimensional discrete time Markov chain and obtain the steady state distributionsystem performance parameters; The validity of the model is verified by simulation, andwe get the diagram which show that according to different number of the time slot,throughput and average delay change.Secondly, from the single channel to multi-channel, we get the steady statedistribution of the multi-channel wireless cognitive network performance parameters, Thesimulation results show that the performance indexes of the RPOSA protocol in this paperobviously superior to the traditional OSA protocol under the single channel andmultiple-channel.Finally, we researched a distributed multi-channel RPOSA protocol on IEEE802.16m,We analyze the proposed RPOSA protocol with three-dimensional discrete time Markovchain model, get the steady-state probability of network performance parameters, and thusobtain performance index of SU. By simulation and analysis, we get the diagram which show that according to different number of the time slot, throughput and packet loss ratechange. Simulation results show that compared with the the traditional OSA protocol, Theprotocol has obvious effect in improving the throughput of802.16m network protocol andreducing packet loss rate, further verify the validity of this protocol.