Mikael Prytz

MIMO On-Frequency Repeater with Self-Interference Cancellation and Mitigation

In this paper, we consider the idea of a MIMO on- frequency repeater (OFR), with end-to-end MIMO channel rank preservation, MIMO aware repeater output-to-input self- interference cancellation, and a new repeater output-to-input beamforming based interference mitigation method for MIMO signals. The latter is used to increase the repeater output-to-input isolation and in turn increase the communication rate and range. The MIMO-OFR idea is compared via simulation to two 2-phase forwarding methods. Through simulation, we observe higher mean channel capacity and improved outage probability for the proposed idea. The viability of the interference feedback mitigation method is also discussed by considering a reflection channel and channel estimation errors for the output-to-input channel, indicating positive potential worth exploring further.

Multi-access Management in Heterogeneous Networks

Communication networks and mobile devices integrate an increasing number of access technologies. At the same time, new business roles emerge, which lead to new cooperation schemes between access providers providing different types of access connectivity. As a result, a variety of access technologies will be available for users at the same time. In this article we present an architecture and a framework capable of integrating different access systems into a multi-access system and selecting the best suited access for users. A utility-based approach is proposed for the evaluation of different access allocation choices, which is based on user and network policies, the performance of access bearers, and the availability of access resources. We present a general multi-access management framework, which integrates the different multi-access related functions: access detection, access evaluation and access selection, which can then lead to an access handover.

Ambient networks: a framework for future wireless internetworking

An increasingly wireless world faces new challenges due to the dynamicity of interactions, range of applications, multitude of available radio access technologies and network functionality. The ambient networks project recognizes these trends and enables the creation of innovative network solutions for mobile and wireless systems beyond 3G. These networks enables scalable and affordable wireless networking while providing pervasive, rich and easy-to-use communication. A specific focus lies on enabling advanced capabilities in environments with increased competition as well as cooperation, environments that are populated by a multitude of user devices, wireless technologies, network operators and business actors. The project adopts a modular architecture that enables plug-and-play control extensibility that supports a wide range of different applications and network technologies. Based on a small subset of common functionality, this approach supports the dynamic deployment of advanced internetworking capabilities, such as media and context-awareness or multi-radio access.

Generic Abstraction of Access Performance and Resources for Multi-Radio Access Management

In this paper abstract metrics for the performance and resource situation of an access system are derived Such an abstraction is needed for multi-access systems where different, typically heterogeneous access systems shall be coordinated in an efficient way. There, the abstractions are used to compare and evaluate different access technologies as part of the access selection process and also to compare the link capabilities or link performance with the service requirements. The abstractions are performed by means of a generic link layer (GLL), which thereby hides the technology-specific characteristics from the access selection performed by multi-radio resource management (MRRM). It is also shown how these abstracted metrics can be used in a number of different access selection algorithms.

Telecommunications Network Design

Telecommunications networks are fundamental in any telecommunications system. The network has to meet a number of criteria for the performance to be satisfactory. Hence, when designing the network, one may pose a number of optimization problems whose solutions give networks that are, in some sense, optimally designed. As the networks have become increasingly complex, the aid of optimization techniques has also become increasingly important. This is a vast area, and this chapter considers an overview of the issues that arise as well as a number of specific optimization models and problems. Often the problems may be formulated as mixed-integer linear programs. Due to problem size and problem structure, in many cases specially tailored solution techniques need to be used in order to solve, or approximately solve, the problems.

Infrastructure Cost Benefits of Ambient Networks Multi-Radio Access

Ambient networks multi-radio access technology for efficient multi-operator multi-radio resource management can provide large advantages in terms of improved services to users, new business opportunities, and cost savings. This paper quantifies the potential infrastructure cost savings through a number of techno-economic infrastructure cost comparisons. The results indicate clear potential cost savings with integrated deployment in suburban and urban areas and additional cost savings with multi-operator cooperation when using the ambient networks multi-radio access technology

Software radio platform for network-assisted device-to-device (NA-D2D) concepts

This paper describes a small-scale software radio platform that has been developed and implemented to investigate the new mobile network concept of Network-Assisted Device-to-Device (NA-D2D) communications. The implementation includes mechanisms for mode selection, direct-link quality estimation, and resource allocation. We show that significant benefits were reaped from this real-world implementation despite the relatively simplistic scenario emulated by our indoor laboratory setup. Apart from the obvious advantages of testing the concept over a real wireless medium with its associated physical characteristics, other unforeseen factors were also uncovered. Asymmetries in radio channels, variations in supposedly identical node hardware, and timing issues, were just some of the experiences encountered and fed back into the research design process which resulted in significant refinements and improvements made to the mechanisms and algorithms of the NA-D2D communications concept studied.

Access Flow based Multi-Radio Access Connectivity

This paper describes the steps and the procedures involved to establish access flows for a user data session in multi-radio access networks. The description is evolved around the overall connectivity abstraction model defined in the ambient networks (AN) project. This model uses access flows as its fundamental objects which are the result of two main access selection procedures: network attachment and flow setup. All access abstractions and procedures have been developed to handle the requirements of efficient multi-access resource management through all stages of access connectivity. The paper discusses some design trade-off for the establishment of access flows concerning setup delays and resource efficiency.