Energy-efficient femtocell networks: challenges and opportunities

Abstract

As a promising technique for next-generation wireless networks, femtocells expand the coverage of cellular networks, provide high data rate for users, decrease the transmission power of user equipments, and increase the spectrum efficiency. In a few years, the number of deployed femtocell base stations (FBSs) will reach hundreds of millions. This huge deployment will bring a lot of challenges in terms of interference management, resource scheduling, and energy consumption. In recent years, more and more attention has been paid to energy-efficient communications. The huge number of deployed FBSs will aggravate energy consumption. In this article, we comprehensively survey the related work on energy efficiency issues in femtocell networks, including energy efficiency metrics, energy consumption models, deployments of femtocells, and energy-efficient schemes. Then a simple sleeping scheme, fixed time sleeping, is presented as a case study for saving the energy of FBSs. Some interesting results are also presented to show that fixed time sleeping makes a good trade-off among energy efficiency, actual waiting time, and call loss.

Green Femtocell Networks through Joint Power Control and 3-Dimensional Pattern-Dependent Beamforming

“…The first terms in both (8) and (9) are the desired signals, while the other terms are related to the interference and noise.…”

“…In the coexisting macrocell-femtocell heterogeneous networks, interference exists between the femtocells and macrocell as well as between neighboring femtocells, especially in dense femtocell deployment scenarios [7]. Furthermore, huge deployment of the femtocells will ultimately make energy efficiency one of the major challenges of these networks [8].…”

Interference and Resource Management Through Sleep Mode Selection in Heterogeneous Networks

“…In [6], the authors provided a survey on energy efficient techniques and power consumption models for enhancing the energy efficiency in femtocell networks. The authors in [7] presented a method for minimizing energy in heterogeneous networks by proposing a joint resource partitioning and user association method under the assumption that both tiers of cells can be switched into SL for a certain fraction of time/frequency.…”

Energy Efficiency for 5G Multi-Tier Cellular Networks

“…For sleep mode operation, small cells can always be managed by operators. Nowadays, efforts have been made related to power saving in cellular networks with the introduction of sleep modes [6][7][8] for BSs. Power consumption is reduced by using sleep mode in low traffic [9] as a case study for saving the energy of macro BSs (MBSs).…”