Energy-Efficient Repulsive Cell Activation for Heterogeneous Cellular Networks

Abstract

Abstract-In this paper, we consider a two-tier heterogeneous cellular network (HCN) where macrocells and distributed low power cells, namely daughtercells, are operated in a common spectrum. Due to the ad-hoc nature of daughtercell BS deployments such as pico and femto cells, the mutual interference varies and obviously the coverage probability behaves differently in terms of transmit powers and densities of macrocells and daughtercells. In this paper, we employ repulsive cell activation in the interfering daughtercell network and see the impact of a minimum separation distance between the daughtercell BSs in terms of coverage under open access and power efficiency. The control of the minimum separation distance plays a role in balancing cell load effectively according to changing user density and is justified for the coexistence of low power daughtercells. The optimal minimum separation distance in terms of user density and target per-tier user throughput requirements is found by a numerical search based on a simple bisection method. Numerical results show the benefit of cell repulsion in terms of increased user density support and less area power consumption.

Joint Energy-Spectral-Efficiency Optimization of CoMP and BS Deployment in Dense Large-Scale Cellular Networks

“…Our formulation of P i cell specifically takes into account the impact of the mobile-traffic intensity λ u . This is in contrast to the existing contributions [25]- [27] which ignore the effects of mobile-traffic by assuming a constant transmit power. 3 There exists a trade off between CoMP diversity and total transmit power.…”

“…However, these existing contributions mainly focus on user-centric performance analysis, such as the coverage probability [23] and the users' average throughput [22], [24], but they ignore the network's EE. In the literature, there exist a few studies addressing the challenging problem of energy efficient BS deployment strategies and network EE analysis [25]- [27]. These studies all recognize that the optimal BS deployment strategy in a randomly deployed dense network is equivalent to minimizing the BS density subject to a coverage probability or outage constraint.…”

“…Then the downlink (DL) transmit power illuminating the coverage area of a typical BS is modeled by deriving the average DL transmit power for a typical No-CoMP user equipment (UE) and CoMP UE. Instead of unrealistically assuming a constant DL BS power consumption as in most existing works [25]- [27], [35]- [39], the quantitative impact of both the users' large-scale behaviors, as well as the inter-BS cooperation degree and large-scale BS deployment parameters are statistically characterized. The network's ESE is defined and derived, together with a comprehensive insight into how the geographic mobile-traffic intensity, the average users' rate, the BS density, the CoMP activation factor and other cellular parameters influence the network's ESE.…”

Energy-Spectral-Efficiency Analysis and Optimization of Heterogeneous Cellular Networks: A Large-Scale User-Behavior Perspective

“…Based on these works, several energy efficient network deployment strategies were proposed in [29]- [32], where the authors aimed either for minimizing the area-power-consumption (APC) of the entire network or for maximizing the network's EE performance by choosing a suitable BS density unilaterally under usercentric performance constraints. To be more specific, in [29], [30], the network's APC was minimized by switching off as many of the BSs as possible. More explicitly, the BS density was minimized, subject to the per-tier coverage/outage performance constraints.…”

Multi-Objective Energy-Efficient Resource Allocation for Multi-RAT Heterogeneous Networks

“…In [22], an energy-efficient coordinated multipoint (CoMP) precoding to maximize the system EE has been proposed for MIMO HetNets. A repulsive cell activation strategy has been developed to achieve an energy-efficient load balance by guaranteeing a minimum separation distance between low-power base stations [23]. Three energy-efficient design strategies have been proposed for HetNets in [24], based on the large-scale user behavior.…”