Optimal power control and coverage management in two-tier femtocell networks

Abstract

In this article, we jointly consider the problem of efficient power control and coverage (PCC) management over an integrated two-tier macrocell/femtocell network towards maximizing the expected throughput of the system subject to appropriate power constraints, under the existence of both co-tier and cross-tier interferences. Optimal network design amounts to joint optimization of users' allocated power levels and cell's maximum aggregated downlink transmitted power, i.e., coverage area management. This problem is inherently difficult because it is in fact a non-convex optimization problem. A novel approach to address the latter is performed that entails a suitable transformation, which allows the use of convex optimization and also forms the basis for the design of a distributed PCC algorithm via performing two-level primal-dual decomposition. PCC algorithm's convergence to optimality is established. We demonstrate that for realistic macrocell/femtocell deployment scenarios, overall system throughput increase up to approximately 50% can be achieved while guaranteeing 70% of power savings.

A Distributed Coverage Adjustment Algorithm for Femtocell Networks

“…Another power control algorithm which focuses on protecting macrocell user's link quality via utilizing feedbacks is introduced in [15]. A coverage management and power control approach to maximize the expected throughput of the system is introduced in [16]. Under an open access scheme, a base station association and power control problem is investigated in [17].…”

A Novel Radio Resource Optimization Scheme in Closed Access Femtocell Networks Based on Bat Algorithm

“…Energy efficiency optimization problem for two-tier macrocell/femtocell networks by considering transmit beamforming design and power allocation policies has been addressed in [14]. The problem of efficient power control and coverage management in two-tier macrocell/femtocell networks is investigated in [15]. In [16], a mixed-integer programming problem is used to tackle the subchannel and power allocation problem with multiple constraints in OFDMA cognitive femtocells.…”

Spectrum optimization in multi-user multi-carrier systems with iterative convex and nonconvex approximation methods

“…The optimal value of each subproblem approximation, i.e., (SUB) in (22), is always non-increasing by design. For the dual optimization step, although the approximations are allowed to be nonconvex, the theoretical duality gap between (20) and (21) tends to zero because of the large number of independent tones [41], [49], i.e., K is very large. In our extensive simulation environment, when using the dual decomposition approach, we always observed convergence to primal feasible solutions, on each of more than a hundred of realistic large scale DSL scenarios.…”

“…This is a model that has been widely considered in literature. More specifically, spectrum optimization or power control (for multi-carrier and single-carrier transmission, respectively) has been considered for different systems: power control for code division multiple access (CDMA) in cellular networks [17], [18], power control for cognitive wireless networks [19], power control for femtocell networks [20], [21], general power control [22], [23], [24], [25], spectrum optimization for multi-user multi-channel cellular relay networks [26], spectrum optimization for heterogeneous wireless access networks [27], and cross-layer power and spectrum optimization [28], [29], [30].…”