Anders Vastberg

Impact of Backhauling Power Consumption on the Deployment of Heterogeneous Mobile Networks

Energy efficiency in cellular mobile radio networks has recently gained great interest in the research community. The development of more energy efficient hardware and software components aside, effect of different deployment strategies on energy efficiency are also studied in the literature. The latter mainly consist of optimizing the number and the location of different types of base stations in order to minimize the total power consumption. Usually, in the literature, the total network power consumption is restricted to the sum of the power consumption of all base stations. However, the choice of a specific deployment also affects the exact implementation of the backhaul network, and consequently its power consumption, which should therefore be taken into account when devising energy efficient deployment. In this paper, we propose a new power consumption model for a mobile radio network considering backhaul. We then handle a case study and perform a comparison of the power consumption of three different heterogeneous network deployments, and show how backhaul has a non-negligible impact on total power consumption, which differs for different deployments. An energy efficiency analysis is also carried out for different area throughput targets.

Energy efficiency gains through traffic offloading and traffic expansion in joint macro pico deployment

The traffic demand in future mobile cellular networks is expected to increase exponentially which would lead to dense base station deployment and eventually higher energy consumption. The current dominant mobile systems including GSM and UMTS were not designed with focus on energy efficiency. This paper investigates the energy saving potential of pico nodes in a heterogeneous network from an incumbent operator consideration. The results show that the number of hotspots and the user distribution in the hotspots strongly effects the power saving. Also, sleep modes in pico base stations have shown to reduce the energy loss to almost half. On a day average with limited utilization of pico base station, the heterogeneous network scenario provides marginal saving. The results also show that if the pico base station resources are fully utilized, premium user case, the heterogeneous network scenario can provide substantial reduction in energy per bit.

Energy efficiency improvement through pico base stations for a green field operator

Mobile telecommunication operators are now focussing on emerging markets due to the current highly competitive mobile telecommunication sector in established markets. The deployment of wireless mobile infrastructure in these emerging markets or a green field scenario requires an innovative energy efficient approach, which is not feasible in an incumbent operator scenario. This paper describes a combined macro and pico cellular heterogeneous wireless network architecture, and analyses its energy efficiency with respect to variation in inter site distance. The increase in capacity and power saving through sparse network deployment is investigated in terms of area spectral efficiency and area power consumption respectively. The results suggest that the deployment of pico cells along with a traditional cellular network can improve the energy efficiency of the network, as well as provide gains in terms of increased inter site distance. Finally. the indifference curves of Energy Efficiency and number of pico nodes indicate the optimum deployment scheme for multiple area spectral efficiency targets.

Energy efficient high capacity HETNET by offloading high QoS users through femto

Bandwidth, network performance, QoS and network power consumption are important dilemmas of contemporary telecommunication networks. With ever increasing demand for data services, networks are destined to become denser and more power hungry, essentially increasing the capital and operational expenditure for operators around the world. One of the technological remedies to this situation is heterogeneous networks. In this work, we present a promising attribute of heterogeneous networks by offloading high QoS indoor users through femto. Additionally, we take traffic demand and sparse network deployment into consideration. The traffic demand is expressed in terms of area spectral efficiency and the power consumed in network nodes is expressed in terms of area power consumption [1]. The results suggest that with an increase in femto density the area spectral efficiency of the considered LTE network increases and decreases monotonously for sparse networks. From an operators point of view, 100% offloading of premium users through femto is energy efficient at all area spectral efficiency targets. From an environmental perspective, 100% offloading of premium users is beneficial at low area spectral efficiency targets, while at high area spectral efficiency targets 40% offloading is energy efficient.

Energy Efficiency in the Wideband Regime

End-to-end communication is the fundamental building block of communication networks. In this paper, we discuss globally optimal energy efficient design for end-to-end communications. An end-to-end multiple-hop system with one sender, one receiver, and multiple relays is considered. We first study in detail energy-efficient designs in the wideband regime that is characterized by wide signal bandwidth and low spectral efficiency, and later briefly those in the narrowband regime. We will reveal the globally optimal link adaptation as well as relay deployment strategies such that the whole system can achieve the highest energy efficiency. The technologies proposed can be used in various communication systems, such as the deployment and communication of wired core networks and wireless relay networks, to improve their energy efficiency. While this paper focuses on a linear end-to-end network topology, the methodology can be easily extended to two-dimensional network topologies for energy-efficient designs of the whole network.

Energy efficiency in the wideband regime

End-to-end communication is the fundamental building block of communication networks. In this paper, we discuss globally optimal energy efficient design for end-to-end communications. An end-to-end multiple-hop system with one sender, one receiver, and multiple relays is considered. We first study in detail energy-efficient designs in the wideband regime that is characterized by wide signal bandwidth and low spectral efficiency, and later briefly those in the narrowband regime. We will reveal the globally optimal link adaptation as well as relay deployment strategies such that the whole system can achieve the highest energy efficiency. The technologies proposed can be used in various communication systems, such as the deployment and communication of wired core networks and wireless relay networks, to improve their energy efficiency. While this paper focuses on a linear end-to-end network topology, the methodology can be easily extended to two-dimensional network topologies for energy-efficient designs of the whole network.

Green distributed antenna systems: Optimized design and upper bound for energy efficiency

Energy efficiency in Distributed Antenna Systems (DAS) has been an overlooked subject in favor of achieving the required coverage. In this paper, we demonstrate that DAS energy efficiency can be improved (in Joule/bit) up to an order of magnitude with retained Quality of Service. We also demonstrate that for an optical-wireless system there can be an optimum number of antennas which maximizes the energy efficiency.

Energy efficient heterogeneous network deployment with cell DTX

This paper evaluates different means of reducing power consumption of macro base stations (BS) and heterogeneous mobile network deployments (HetNet) considering the time dimension. These approaches are based on the same idea of reducing the load of heavily loaded macro cells and putting them to discontinuous transmission (DTX) mode during the time of inactivity by either (1) macro cell densification or (2) offloading traffic to small cells. Activity factor of a BS is defined as the fraction of time the BS is transmitting over a fixed time period. It is shown that by macro cell layer network densification, the average daily area power consumption can be reduced by up to 73 % with the use of cell DTX. However, reducing the activity factor by macro layer densification is not cost effective, as already demonstrated in previous studies. Alternatively, by adding small cells and enabling their DTX capability, power consumption can be reduced by up to 29 %. Adding small cells is especially effective in terms of energy savings, when users are distributed around hot spots, where additional coverage and capacity is required.