LTE-Advanced - Evolving LTE towards IMT-Advanced

Abstract — 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. Keywords-LTE, IMT-Advanced, LTE-Advanced, 4G I

The 3G Long-term Evolution- Radio Interface Concepts and Performance Evolution

Abstract—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 threefold 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 an

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. © 2006 IEEE.status: publishe

INFSO-ICT-247733 EARTH

In order to quantify the energy savings in wireless networks, a holistic view of the power consumption of the entire system needs to be captured. This requires an appropriate energy efficiency evaluation framework. In this deliverable, we present the necessary enhancements over existing performance evaluation frameworks for the wireless networks. The main objective is to capture the factors affecting the energy efficiency at component, node and network level. The most important additions to the existing frameworks include: (1) a sophisticated power model for various BS types, that maps the RF output power radiated at the antenna elements to the total supply power necessary to operate the network; (2) an approach to quantify the energy efficiency of large geographical areas by using the existing small scale deployment models along with long term traffic models; (3) a suitable set of metrics that allows quantifying the amount of energy savings capturing the most important trade-offs between energy savings and maintaining the system capacity, network coverage and quality of service parameters. After presenting the framework and necessary components of the framework, the proposed evaluation framework is applied to quantify the base station energy efficiency of 3GPP LTE. The overall promise of energy efficiency improvement is further investigated qualitatively for different possible areas of improvement in the system and some fundamental technology potential limits are also identified

On-line separation of short-lived beryllium isotopes

With the development of a new laser ionization scheme, it became possible to ionize beryllium efficiently in the hot cavity of the ISOLDE laser ion source. The high target and ion source temperatures enable the release of short-lived beryllium isotopes. Thus all particle-stable beryllium isotopes could be extracted from a standard uranium carbide/graphite target. For the first time the short-lived isotopes /sup 12/Be and /sup 14/Be could be identified at an ISOL facility, /sup 14/Be being among the most short-lived isotopes separated so far at ISOLDE. The release time from the UC/graphite target was studied with several beryllium isotopes. Profiting from the element selectivity of laser ionization, the strong and isotopically pure beam of /sup 12/Be allowed to determine the half- life to T/sub 1/2 /=21.34(23) ms and the probability of beta-delayed neutron emission to P/sub n/=0.48/sub -0.10//sup +0.12/(23 refs)