Ylva Jading

LTE: the evolution of mobile broadband

This article provides an overview of the LTE radio interface, recently approved by the 3GPP, together with a more in-depth description of its features such as spectrum flexibility, multi-antenna transmission, and inter-cell interference control. The performance of LTE and some of its key features is illustrated with simulation results. The article is concluded with an outlook into the future evolution of LTE.

Challenges and enabling technologies for energy aware mobile radio networks

Mobile communications are increasingly contributing to global energy consumption. In this article, a holistic approach for energy efficient mobile radio networks is presented. The matter of having appropriate metrics and evaluation methods that allow assessing the energy efficiency of the entire system is discussed. The mutual supplementary saving concepts comprise component, link and network levels. At the component level the power amplifier complemented by a transceiver and a digital platform supporting advanced power management are key to efficient radio implementations. Discontinuous transmission by base stations, where hardware components are switched off, facilitate energy efficient operation at the link level. At the network level, the potential for reducing energy consumption is in the layout of networks and their management, that take into account slowly changing daily load patterns, as well as highly dynamic traffic fluctuations. Moreover, research has to analyze new disruptive architectural approaches, including multi-hop transmission, ad-hoc meshed networks, terminal-to-terminal communications, and cooperative multipoint architectures.

LTE-Advanced - Evolving LTE towards IMT-Advanced

This paper provides a high-level overview of some technology components currently considered for the evolution of LTE including complete fulfillment of the IMT-advanced requirements. These technology components include extended spectrum flexibility, multi-antenna solutions, coordinated multipoint transmission/reception, and the use of advanced repeaters/relaying. A simple performance assessment is also included, indicating potential for significantly increased performance.

Reducing Energy Consumption in LTE with Cell DTX

This paper discusses how energy consumption can be significantly reduced in mobile networks by introducing discontinuous transmission (DTX) on the base station side. By introducing DTX on the downlink, or cell DTX, we show that it is possible to achieve significant energy reductions in an LTE network. Cell DTX is most efficient when the traffic load is low in a cell but even when realistic traffic statistics are considered the gains are impressive. The technology potential for a metropolitan area is shown to be 90% reduced energy consumption compared to no use of cell DTX. The paper also discusses different drives for the increased focus on energy efficient network operation and also provides insights on the impact of cell DTX from a life cycle assessment perspective.

The 3G Long-Term Evolution - Radio Interface Concepts and Performance Evaluation

3GPP is in the process of defining the long-term evolution (LTE) for 3G radio access, sometimes referred to as super-3G, in order to maintain the future competitiveness of 3G technology. The main targets for this evolution concern increased data rates, improved spectrum efficiency, improved coverage, and reduced latency. Taken together these result in significantly improved service provisioning and reduced operator costs in a variety of traffic scenarios. This paper gives an overview of the basic radio interface principles for the 3G long-term evolution concept, including OFDM and advanced antenna solution, and presents performance results indicating to what extent the requirements/targets can be met. It is seen that the targets on three-fold user throughput and spectrum efficiency compared to basic WCDMA can be fulfilled with the current working assumptions. More advanced WCDMA systems, employing e.g. advanced antenna solutions may however achieve similar performance gains. Enhancements for reduced latency and IP optimized architectures and protocols are further applicable to both LTE and WCDMA

A case study on estimating future radio network energy consumption and CO 2 emissions

In this paper we examine the potential impact on total network energy consumption and CO2 emissions when LTE is introduced into an existing cellular network. We note that by replacing existing 2G or 3G hardware with modern equipment the energy consumption per node can be reduced by approximately 50% already today. Furthermore, based on power models from the EARTH project, we predict that this potential gain will continue to increase year by year. In the paper we show that it is possible to reduce the total network energy consumption by approximately 60% by 2020 compared to today, despite deploying LTE, if we modernize the existing legacy hardware at the same pace as LTE is rolled out. Vodafone has a CO2 reduction target of reducing emissions by 50% in the mature market by 2020 compared to the reference year 2006/07, and this target appears to be realistic to reach.

Enhanced WCDMA Fingerprinting Localization Using OTDOA Positioning Measurements from LTE

The focus of this paper is on the convergence of positioning technology between the WCDMA and the LTE cellular systems. The emerging possibility to use multi-RAT positioning nodes can be exploited to mitigate the lack of a high-precision indoor OTDOA positioning method in WCDMA, which today limits the coverage of self-learning databases for fingerprinting positioning in this cellular system. The problem at hand is solved by use of measured high precision OTDOA positions of opportunity from LTE.