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UBC Theses and Dissertations

Scheduling and power allocation for interference mitigation in heterogeneous cellular networks Pradhan, Shristi Nhuchhe


The wireless industry is confronted with an exponentially increasing demand for ubiquitous wireless coverage and larger data rates. Recent studies have shown that the spectral efficiency of a point-to-point link in cellular networks has approached its theoretical limit. This demands an increase in the node density in order to further improve the network capacity. However, today's network already has dense deployments and high intercell interference severely limits the cell splitting gains. Moreover, high capital and operational expenditure associated further limit the deployment of high power macro nodes. In this thesis, we investigate on Heterogeneous Networks (HetNets), a new paradigm for increasing cellular capacity and coverage to meet the forecasted explosion of data traffic. HetNets consist of low power nodes such as pico and femto overlaid over a macrocell network. Nevertheless, the deployment of large number of small cells overlaying macrocells presents new technical challenges. We focus on interference management issues in HetNets and present user scheduling and power allocation schemes for interference mitigation. We investigate the performance of user scheduling and power allocation techniques for interference mitigation in HetNets. We present analytical modeling and propose improved solutions using results from the model and computer simulations. First, we propose a scheme to jointly minimize network outage probability and power consumption. Second, we propose a scheme to jointly maximize network throughput and minimize power consumption. Both these schemes guarantee Quality of Service (QoS) provisioning in HetNets. We analyze the intrinsic trade-off between network performance parameters, i.e., outage and power consumption; throughput and power consumption using multi-objective optimization approach. Different user scheduling schemes have been adopted such as best user selection, proportional fairness and round-robin. Thirdly, we also propose an energy efficient power allocation method and analyze its performance with guaranteed QoS provisioning. For all the proposed algorithms and schemes we provide extensive simulation based results.

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