Dragan Boscovic

m@ANGEL: autonomic management platform for seamless cognitive connectivity to the mobile internet

B3G wireless access infrastructures can be realized through the concept of cognitive networks. In a B3G context, a network operator will rely on various alternate wireless access technologies, for realizing the appropriate business goals, such as capacity and QoS levels. Cognitive wireless access networks dynamically change their configuration, and in this respect the radio access technologies and spectrum used at the physical and MAC layers, in order to adapt to environment conditions. A cognitive infrastructure consists of reconfigurable elements and intelligent management functionality. This article focuses on the management part. We present a platform, called m@ANGEL, which adheres to autonomic computing principles, and aims at the provision of seamless cognitive connectivity to the mobile Internet. Our work starts from a business level view of cognitive wireless access networks. Technical requirements for m@ANGEL are identified, and the architecture of the platform is described. Moreover, the article describes the functionality and engineering challenges of the m@ANGEL components, which provide the means for monitoring, discovery, context acquisition, description of profiles/goals/agreements, resource and service brokerage, configuration negotiation, selection, and implementation. Finally, concluding remarks are drawn, and issues for the next phases of our work are identified

Dispersion Characteristic of Coupled Inset Dielectric Guides

The inset dielectric quide (IDG) represents an easy-to-fabricate alternative to image line that is also less sensitive to loss by radiation at discontinuities. The propagation constants of single and coupled identical IDGs have been calculated under the LSE approximation. The Transverse Resonance Diffraction (TRD) method with variational formulation for impedance operators is used. Measured values show very good agreement with predicted values for the propagation constant of a single IDG and for the coupling coefficient of coupled IDGs.

Toward the Green Video CDN

Content Delivery Networks (CDN) play an important role in todays video distribution system. While its advantage of efficient content delivery is well understood, the energy consumption of the video CDN system needs to be understood since energy saving recently has become a key challenge for the system designers and operators. This paper investigates the energy efficiency aspect of a video CDN system by firstly analyzing and defining the energy efficiency of a video CDN system, followed by two possible energy efficiency improvements, which are based on the idea of intelligent coordination among edge video servers.

Cognitive cloud-oriented wireless networks for the Future Internet

It is expected that the wireless world will migrate towards an era that will comprise more local/ temporary structures for the provision of services. A networking paradigm towards this direction is the opportunistic networking. Operator-governed ONs are dynamically created, temporary, coordinated extensions of the infrastructure. Operator governance is being realized through the use of Cognitive Management Systems which acquire the context, policies and profiles of the environment and make decisions on the creation of opportunistic networks. The paper presents an approach for exploiting such ONs in order to extend the capacity in wireless access and backhaul segments for efficient application provisioning, as well as an evaluation of indicative test cases as a proof of concept of the aforementioned approach. All these scenarios will enable the cognitive cloud-oriented vision of wireless networks for efficient application provisioning in the Future Internet era.

Advanced methodology for spectrum engineering

This paper describes a novel concept and its supporting methodology, referred to as Radio Ecology/sup TM/, which consider not only technical parameters, but also regulatory and economic factors in order to provide optimal solutions to complex radio compatibility and spectrum engineering problems. A practical example related to UMTS and IS-95 technologies is given to illustrate the impact and usefulness of the proposed methodology.

Statistical approach to the spectrum engineering practices

We describe the merits of a software tool based upon the statistical Monte Carlo technique which is capable of analysing complex radio system compatibility issues. The tool can be used to help spectrum engineers make the most efficient use of the limited radio frequencies available. It is able to help identify candidate frequency bands for radio systems; determine the appropriate size of guard bands; derive transmitter emission masks needed to protect adjacent services; specify receiver susceptibility to preserve system performance in a given radio environment; identify band sharing issues between different services and technologies and provide smooth band re-farming strategies. A description of the tool is provided as well as an explanation of its applicability. In addition there are a number of examples illustrating the usefulness of the tool.

Spurious emission limits for mobile transmitters: an approach and results

This paper describes a Monte-Carlo method for evaluating discrete spurious emission limits. Building upon extensive data for receiver characteristics from an original CEPT (Conference of European Posts and Telecommunications) report, the technique was developed in order to determine the magnitude of the potential spurious emission problem by calculating the probability of interference. Parameters of existing receiving systems in different frequency bands are combined with realistic propagation models, log normal shadowing, of both the wanted and interfering signals, and likely future transmitter densities. Many Monte-Carlo trials are used to determine coverage losses due to interference from spurious emissions at different limit levels. The evaluation shows that conducted spurious emissions at the current ITU limit of (-16 dBm) will result in negligible probabilities of interference attributable to discrete spurious emissions even in dense urban environments.

Impact of different content placement and delivery strategies on content delivery capacity of the wireless mesh networks

Wireless mesh networks are introduced as a way for providing cheap, easily deployable and maintainable access to core networks services. The content delivery capacity of these networks directly depends on the number of installed wireless mesh network gateways. In this paper, we present analysis of impact of content placement on nodes of wireless mesh network on the total streaming capacity of that network. Our analysis shows that networks streaming capacity, with respect to given topology and cached content, can be equally increased with content placement on access points of the network, as it would be increased with installation of additional gateways.

Business Models of End-to-End Reconfigurable Systems

The objectives of the end-to-end reconfigurability (ER) research are to bring the full benefits of the valuable diversity within the radio eco-space, composed of a wide range of systems and to devise, develop and trial architectural design of reconfigurable devices and supporting system functions to offer an expanded set of operational choices to the different actors of the value chain. The end-to-end reconfigurability helps operators to better exploit their investments on infrastructures and terminals and should ensure that the infrastructure is flexible and reconfigurable to accommodate evolving standards, applications and the end-user needs. This paper introduces briefly the overall E2R project system research then focuses on the business perspectives of end-to-end reconfigurability, introducing the business systems architecture process (BSAP) methodology. The business use-cases investigated by the E2R research project are presented, as well as the overall business model for end-to-end reconfigurable systems

New linear PMR technology: a new RF parameter for standardisation

Recently published results concerning linearised RE amplifiers have indicated that wide band noise, resulting from the linearisation processes involved and spanning several adjacent channels, may exist. As standards and systems using linear technology are increasingly introduced into new mobile radio systems, the impact of this type of interference must be investigated. Extensive simulation work has been conducted and this paper presents the results on interference probability for a range of wide band noise levels. The level of interference is measured in terms of the area coverage loss. Based on this, a level of 10 dB below the adjacent channel splatter is recommended as a realistic level for wide band noise in future linear radio based PMR systems.<<ETX>>