Networking Solutions for Integrated Heterogeneous Wireless Ecosystem

As wireless communications technology is steadily evolving to improve the offered connectivity levels, additional research on emerging network architectures is becoming timely to understand the applicability of both traditional and novel networking solutions. This chapter concentrates on the utilization of cloud computing techniques to construct feasible system prototypes and demonstrators within the rapidly maturing heterogeneous wireless ecosystem. Our first solution facilitates cooperative radio resource management in heterogeneous networks. The second solution enables assisted direct connectivity between proximate users. The contents of the chapter outline our corresponding research and development efforts as well as summarize the major experiences and lessons learned

Quantifying Potential Energy Efficiency Gain in Green Cellular Wireless Networks

Conventional cellular wireless networks were designed with the purpose of providing high throughput for the user and high capacity for the service provider, without any provisions of energy efficiency. As a result, these networks have an enormous Carbon footprint. In this paper, we describe the sources of the inefficiencies in such networks. First we present results of the studies on how much Carbon footprint such networks generate. We also discuss how much more mobile traffic is expected to increase so that this Carbon footprint will even increase tremendously more. We then discuss specific sources of inefficiency and potential sources of improvement at the physical layer as well as at higher layers of the communication protocol hierarchy. In particular, considering that most of the energy inefficiency in cellular wireless networks is at the base stations, we discuss multi-tier networks and point to the potential of exploiting mobility patterns in order to use base station energy judiciously. We then investigate potential methods to reduce this inefficiency and quantify their individual contributions. By a consideration of the combination of all potential gains, we conclude that an improvement in energy consumption in cellular wireless networks by two orders of magnitude, or even more, is possible.Comment: arXiv admin note: text overlap with arXiv:1210.843

Networking Solutions for Integrated Heterogeneous Wireless Ecosystem

This work targets at applying computer networking techniques to address challenges in modern wireless networks and in various environments built around these networks. The main focus of the work is on designing and implementing prototypes and demonstrators to support research in domains of heterogeneous networks (HetNets). These research domains include centralized radio resource management in emerging cellular network architectures, network assistance role in device-to-device (D2D) communications, and studying prospective services in these networks. Within the research group the author was tasked with designing network architectures and demonstrating certain connectivity and functionality interesting for the research. The author was responsible for modifying commercial off-the-shelf equipment to become suitable for target research scenarios, selecting network technologies to achieve connectivity requirements, deploying network architecture entities within the research group's cloud platform. For HetNet track, the primary goal was to design a platform that would mimic a device connected through a heterogeneous network, allowing researchers to experiment with traffic flow optimization in an environment close to the envisioned next-generation network architecture. Prototype solution and testbed were designed building on software defined network principles of automation, abstraction and software based flow switching, and were implemented using overlay networks and virtual network functions. Within D2D communications research, the task was to design architecture demonstrating feasibility of traffic offloading from infrastructure network to direct links. Prototype was implemented with automated routing control in overlay network. To demonstrate novel services enabled by advanced security frameworks, D2D platform was augmented and a new network application has been implemented, also suitable for wearable electronics

Analytical Performance Evaluation of Cooperative and Multi-Radio Concepts in Emerging Wireless Networks

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Interference control and radio spectrum allocation in shared spectrum access

With demands on the radio spectrum intensifying, it is necessary to use this scarce resource as efficiently as possible. One way forward is to apply flexible authorization schemes such as shared spectrum access. While such schemes are expected to make additional radio resource available and lower the spectrum access barriers, they also bring new challenges toward effectively dealing with the created extra interference which degrades the performance of networks, limiting the potential gains in a shared use of spectrum. In this thesis, to address the interference issue, different spectrum access schemes and deployment scenarios are investigated.  Firstly, we consider licensed shared access where database-assisted TV white space network architecture is employed to facilitate the controlled access of the secondary system to the TV band. The operation of the secondary system is allowed only if the quality of service experienced by the incumbent users is preserved. Furthermore, the secondary system should benefit itself from utilizing the TV band in licensed shared access mode. One challenge for efficient operation of the licensed secondary system is to control the cross-tier interference generated at the TV receiver, taking into account the self-interference in the secondary system.  Secondly, we consider co-primary shared access where multiple operators share a part of their spectrum. This can be done in two different operational levels, users and cells. The user level is done in the context of D2D communications where two users subscribed to different operators can transmit directly to each other. The cell level allows spectrum sharing between two small cells, e.g., indoor and outdoor small cells, in a dense urban environments. The main challenges for such scenarios are to manage the cross-tier interference generated by other users or cells subscribed to different operators, and to identify the amount of radio spectrum each operator contributes.  There are several approaches to reduce the risk of interference, but they often come at a high price in terms of complexity and signaling overhead. In this thesis, we aim to propose low complexity mechanisms that take interference control and radio spectrum allocation into account. The proposed mechanisms are based on tractable models which characterize the effects of the fundamental design parameters on the system behavior in shared spectrum access. The models are leveraged to capture the statistic of the aggregate interference and its effects on the performance metrics