Improved Phantom Cell deployment for Capacity Enhancement

Vastly increasing capacity and coverage demand in communication networks accompanied by energy efficiency challenge is getting attraction in research topics of this area. In this paper, an improved structure of Phantom cell heterogeneous networks (HetNets) is proposed to fulfil these requirements in the next generation cellular networks.It will be shown that the proposed orthogonal frequency-division multiple access (OFDMA) based structure can be employed in both indoor and outdoor environments by applying two individual frequency bands. Furthermore, the resource allocation problem of the proposed structure is investigated in downlink path. To this aim, a proper algorithm is presented in order to maximize the total throughput of all phantom cell users' equipments with regard to the protected minimum network capacity of the existing macrocell. To fulfil the objective goal, an iterative approach is employed in which OFDM subchannels and power transmitted by base stations are sequentially assigned and optimized at each step for every single frequency band. It is showed that the overall joint subchannel and power allocation algorithm converges to local maximum of the original designed problem. Performance improvement of the proposed algorithm is confirmed in both indoor and outdoor environments by numerical results. Keywords-Phantom cells; Femtocells; Hetrogenous Networks, Carrier aggregation; Resource allocation