Capacity Enhancement in Cognitive Radio Wireless Network with Dynamic Spectrum Access

Deployment of femto-cells underlaying the macrocell has been proven to greatly improve the system capacity and the indoor coverage. However, to successfully deploy this heterogeneous network, the interference among the macro-cell and femto-cells, as well as the interference between femto-cells, which are respectively called cross tier and intra-tier interferences, must be mitigated. Cognitive radio is the most promising technique for interference avoidance and mitigation in two-tier heterogeneous networks. Different interference mitigation approaches have been studied including antenna beamforming and orthogonal radio resource assignment. We quantify in this paper the performance of a new spectrum sharing scheme using Markov chains modeling, and which attempt to enhance the secondary system performances while canceling the cross-tier interferences.