A topology control mechanism for cognitive smallcell networks under heterogeneous traffic

The deployment of Heterogeneous Networks (Het-Nets), specifically the smallcell networks ranging from picocells, microcells and femtocells, have been increased dramatically with the proliferation of next generation wireless devices and broad traffic demands. Embedding the promising Cognitive Radio (CR) technology into the smallcells have brought complementary increases in spectrum utilization as well as the topological flexibility. This paper deals with the topological control of such CR based smallcell networks by considering the spectrum utilization, packet losses, delay and jitter parameters. The proposed framework analytically models the spectral topology assignment taking into account the analysis of the CR user requests and decides to assign the proper spectrum to the CR smallcell users by dividing the topology in an optimal manner. This optimality is achieved by taking into account different Quality of Service (QoS) parameters like throughput, delay, jitter and packet losses. The proposed frameworks´ mathematical model also provides optimal QoS parameter values for more efficient and fair topology assignment, considering the heterogeneous background CR traffic in the surrounding. The proposed method is evaluated for different types of CR traffics and thorough simulation results show that the proposed topology control mechanism provides an optimum number of smallcell CR networks to maintain fair and efficient QoS requirements in the unlicensed bands.