Network architecture model of infrastructure based mobile cognitive radio system in licensed band with blocking probability assessment

摘要

Performance of Cognitive Radio (CR) is affected by the estimation of availability of vacant channels based on traffic distribution observation of licensed users. Telecom traffic prediction at a particular instant depends on thorough knowledge of day of the week, hour of the day and instant of the hour. Distributed cooperative spectrum sensing is infrastructure based in which the sensor nodes themselves takes several iteration to arrive at decision about vacant channels where CR nodes have no previous knowledge about each channel behaviour. The proposed network is also architecture based but channel availability decision is taken by a separate control unit called Cognitive Radio-Base Station Controller (CR-BSC). In this architecture, SU functions as probe for occupied primary and secondary channels available in the environment and transmit to Cognitive Radio-Base Station (CR-BS) for periodic updation of channel status database. Frequency of probing and transmission to CR-BS consumes good quantum of energy of SU and needs to be scheduled properly for optimum SU battery life. On placement of SU call, minutewise prediction is done for next few minutes for available set of channels and its blocking probability when both secondary user traffic together with primary user traffic are present in the system. The results obtained have been validated through live mobile data of primary user network.