Deutsche Telekom

About: Deutsche Telekom is a company organization based out in Welwyn Garden City, United Kingdom. It is known for research contribution in the topics: Telecommunications network & Signal. The organization has 3473 authors who have published 5208 publications receiving 65429 citations. The organization is also known as: DTAG & German Telecom.

The E3 architecture: enabling future cellular networks with cognitive and self-x capabilities

Abstract: Future mobile networks are expected to be complex heterogeneous systems. On the one hand this will enable users to take advantage of a number of different access technologies. On the other hand it will seriously affect network management procedures since more extensive operations and decisions will have to be dealt with. To tackle these challenges a number of new dynamic mechanisms need to be designed. It is imperative that certain network management tasks have to be performed without human intervention to reduce the OPEX costs and achieve faster responses in different events. To achieve this goal, the introduction of self-x functionalities, combined with cognitive mechanisms and the ability to reconfigure network entities and terminals, is required. Moreover, the introduction of a new pilot channel needs to be considered to assist the terminals in selecting the most suitable radio access technology according to their requirements. We present the functional architecture of an evolved network that was designed in the context of the EU-funded IP project 'E3: End-to-End Efficiency'. This architecture aims to enhance existing procedures usually performed in traditional operation and maintenance systems (e.g. spectrum management, network planning, configuration actions). We explain the rationale of our design and provide specific examples to illustrate the role of the different functional entities and their interfaces. A considerable part of this architecture has recently been approved as a feasibility study by the ETSI Committee Reconfigurable Radio System. Copyright © 2010 John Wiley & Sons, Ltd.

Investigations of single frequency networks for digital mobile radio systems based on COFDM

Abstract: The application of COFDM (coded orthogonal frequency division multiplexing) transmission schemes allows the implementation of power and bandwidth efficient transmitter networks, the so-called single frequency networks. Dependent on the network configuration, the transmission quality can be improved by macro diversity gain, but contrary to that fact, self interference can lower system performance in several locations of the coverage area. The knowledge of these effects is important for network planning. New measurement techniques are required to investigate the properties of single frequency networks. In this contribution, a wideband channel sounder is described for measuring complex transfer functions of the radio channels within a single frequency network. The method is especially designed to distinguish between the signal components of the different transmitters. The complex superposition of the signals in a single frequency network is obtained additionally. The procedure was tested in several field trials. Some results of the evaluation of the measurements are given in the paper.

JoKER: Trusted Detection of Kernel Rootkits in Android Devices via JTAG Interface

Abstract: Smartphones and tablets have become prime targets for malware, due to the valuable private and corporate information they hold. While Anti-Virus (AV) program may successfully detect malicious applications (apps), they remain ineffective against low-level rootkits that evade detection mechanisms by masking their own presence. Furthermore, any detection mechanism run on the same physical device as the monitored OS can be compromised via application, kernel or boot-loader vulnerabilities. Consequentially, trusted detection of kernel rootkits in mobile devices is a challenging task in practice. In this paper we present 'JoKER' - a system which aims at detecting rootkits in the Android kernel by utilizing the hardware's Joint Test Action Group (JTAG) interface for trusted memory forensics. Our framework consists of components that extract areas of a kernel's memory and reconstruct it for further analysis. We present the overall architecture along with its implementation, and demonstrate that the system can successfully detect the presence of stealthy rootkits in the kernel. The results show that although JTAG's main purpose is system testing, it can also be used for malware detection where traditional methods fail.

Virtual customer integration in the innovation process: Evaluation of the web platforms of multinational enterprises (MNE)

Abstract: Integrating the customer in the innovation process is believed to be a powerful means to reduce failure rates and to increase the revenue from new products. Although many companies have launched programs to enable such integration, the understanding of the mechanisms behind successful programs remains limited. Furthermore, the benefit of integrating customers in the innovation process has to be weighed against the costs. Virtual customer integration has been discussed as a way to limit these costs and bring the benefits of potentially unlimited scalability. Using a sample of the Euro Stoxx 50 companies, we shed light on the various types of virtual customer integration platforms, their limitations, their benefits and the mechanisms that have to be put in place to make them succeed. Results indicate that only a limited number of platforms go beyond the sourcing of ideas. Especially the integration of the customer in the execution phase of the innovation process remains largely limited to digital goods.

Improving routing performance in wireless ad hoc networks using cross-layer interactions

Abstract: This article presents a combined layer two and three control loop, which allows prediction of link breakage in wireless ad hoc networks. The method monitors the physical layer transmission mode on layer two and exploits the gained knowledge at layer three. The mechanism bases on link adaptation, which is used in IEEE 802.11a WLAN to select the transmission mode according to the link quality. The process of link adaptation contains information that is useful to predict link stability and link lifetime. After introducing the IEEE 802.11a Medium Access Control (MAC) and PHY layer, we present insight to the IEEE 802.11a link adaptation behaviour in multi-hop ad hoc networks. The link adaptation algorithm presented here is derived from Auto Rate Fallback (ARF) algorithm. We survey the performance gain of two newly developed route adaptation approaches exploding the prediction results. One approach is Early Route ReArrangement (ERRA) that starts a route reconstruction procedure before link breakage. Hence, an alternative route is available before connectivity is lost. Early Route Update (ERU) is a complementing approach that enhances this process, by communications among routing nodes surrounding the breaking link. The delay caused by route reconstruction can be significantly reduced if prediction and either of our new route discovery processes is used.