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Deploying cognitive radio femtocell network (CRFN) inside a macrocell network can significantly increase the utilization of the available macrocell bandwidth and increase the capacity of the macrocell. However, the success of this deployment in terms of performance degradation of the macrocell and the acceptable throughput for the CRFN is not well defined. In this paper, we propose a time division duplex (TDD) operation of a CRFN and investigate its performance inside a macrocell operating in frequency division duplex (FDD) mode. It is shown that with a proper sensing and transmission scheme the capacity of the CRFN can be increased by simultaneous transmissions on multiple channels, water-filling further improves the result when interference from the macrocell basestation is large. The proposed scheme is applicable to full duplex networks, such as LTE and GSM.

SUMMARYBandwidth management and traffic control are critical issues to guarantee the quality of service in cognitive radio networks. This paper exploits a network load refinement approach to achieve the efficient resource utilization and provide the required quality of service. A connection admission control approach is introduced in cognitive radio multimedia sensor networks to provide the data transmission reliability and decrease jitter and packet end-to-end delay. In this approach, the admission of multimedia flows is controlled based on multimedia sensors' correlation information and traffic characteristics. We propose a problem, connection admission control optimization problem, to optimize the connection admission control operation. Furthermore, using a proposed weighting scheme according to the correlation of flows issued by multimedia sensors enables us to convert the connection admission control optimization problem to a binary integerprogramming problem. This problem is a kind of a Knapsack problem that is solved by a branch and bound method. Simulation results verify the proposed admission control method's effectiveness and demonstrate the benefits of admission control and traffic management in cognitive radio multimedia sensor networks.