Russell John Haines

Emerging technologies and research challenges for 5G wireless networks

As the take-up of Long Term Evolution (LTE)/4G cellular accelerates, there is increasing interest in technologies that will define the next generation (5G) telecommunication standard. This article identifies several emerging technologies which will change and define the future generations of telecommunication standards. Some of these technologies are already making their way into standards such as 3GPP LTE, while others are still in development. Additionally, we will look at some of the research problems that these new technologies pose.

M2M communications for E-health and smart grid: an industry and standard perspective

An overview of several standardization activities for machine-to-machine communications is presented, analyzing some of the enabling technologies and applications of M2M in industry sectors such as smart grid and e-Health. This summary and overview of the ongoing work in M2M from the industrial and standardization perspectives complements the prevalent academic perspective of such publications to date in this field.

Toward Formal Verification of 802.11 MAC Protocols: Verifying a Petri-Net Model of 802.11 PCF

The delivery of traffic with stringent Quality of Service (QoS) requirements over wireless local area networks (WLAN) is a vital research topic. A solution is to adopt centralized control functions, which allocate part of the bandwidth to polling traffic and part to contending traffic. Reliable means of performing this allocation are required as this allocation directly determines how well the two forms of traffic can coexist. In an earlier publication we presented an extended Petri-net model of an IEEE802.11 centralized control scheme, and used this model in the manner of a simulation tool to analyze performance, promising analysis of the model to come. Here we perform verification on aspects of the model to verify key properties of the system, something that is only possible by virtue of the strong mathematical basis of Petri-nets.

Cognitive Pilot Channels for femto-cell deployment

The Cognitive Pilot Channel (CPC) is a mechanism for disseminating information about available radio access technologies to future reconfigurable devices. This paper proposes and investigates the idea that CPC technology for heterogeneous cognitive radio networks may present an attractive solution to some of the challenges facing femto-cell deployment. The benefits of using the CPC in this way are described and a comparative analysis of this approach against fixed-line oriented solutions is presented. As a result of this comparison the viability of the CPC approach in both the short-and long-term is discussed.

Industrial Prototyping: A Common Architecture and Case Study of IEEE 802.11n Transmit Beamforming

Prototyping is a means to rapidly test the feasibility of a design before entering a full design process or mass production. An important consideration within industrial research is the transfer of technology from the research domain to business units. Prototypes are a tangible example that aid in explanation and dissemination of the developed intellectual property. In this paper, we present a common architecture of the Wireless Evaluation Research Platform (WERP), developed at Toshiba Telecommunications Research Laboratory. WERP is used for prototyping and analysis of algorithms that aid in technology transfer. A case study is presented to illustrate the use of WERP in the analysis of IEEE 802.11n transmit beamforming with explicit feedback. WERP is used in many different configurations for research purposes, two of these configurations are presented in this case study. Results from the case study are presented and conclusions drawn.

Petri-nets for formal verification of MAC protocols

Full or partial reconfiguration of communications devices offers both optimised performance for niche scenario-specific deployments and support for de-regulated radio spectrum management. The correctness of the protocols or protocol-enhancements being deployed in such a dynamic and autonomous manner cannot easily be determined through traditional testing techniques. Formal description techniques are a key verification technique for protocols. The Petri-net formal description technique offers the best combination of intuitive representation, tool-support and analytical capabilities. Having described key features and analytical approaches of Reference-nets (an extended Petri-net formalism), a case study is presented applying this approach to a contemporary research area: IEEE 802.11 centralised control mechanisms to support delay-sensitive streams and bursty data traffic. This case study showcases the ability both to generate performance-oriented simulation results and to determine more formal correctness properties. The simulation results allow comparison with published results and show that a packet-expiration mechanism places greater demands on the contention-free resource allocation, while the mathematical analysis of the model reveals it to be free of deadlock and k-bounded with respect to resources. The work demonstrates the potential that the Petri-net formal method has for analysing process and protocol models to support reconfigurable devices.

Efficient modeling of correlated shadow fading in dense wireless multi-hop networks

Correlated shadow fading has a detrimental effect on the performance of wireless systems. Neglecting shadowing correlations could lead to inaccurate simulation results and unreliable wireless system design. In this paper, we propose and analyze a correlated shadow fading model based on Gaussian random fields. The model enables the generation of spatially correlated shadow fading for all meshed links in wireless multi-hop networks. Both analytical and numerical results show that the proposed model is in good agreement with the literature in terms of the statistical properties and correlation coefficients. Furthermore, the Circulant Embedding method of the proposed simulation model significantly reduces the computational cost.

Distributed resource allocation in small cellular networks - Test-bed experiments and results

The advent of femto-cellular base stations brings with it a promise for increased cellular coverage and capacity. However, several challenges need to be met in order to fulfil these promises. Femto-cells are likely to be deployed in an adhoc manner due to the infeasibility of carrying out comprehensive spectrum planning as in legacy cellular networks. One of the major issues with such a deployment is the problem of interference between cells. It is possible that femto-cells may interfere with their neighboring cells if they use the same frequency resources. This paper proposes a distributed radio resource management (DRRM) algorithm to address this problem and studies its performance through experiments in a test-bed. Results from this study indicate that the proposed algorithm can significantly improve performance compared to the randomized allocation regime. In light of the deployment considerations, the results are particularly significant given the simplicity and practicality of the proposed solution.

Bandwidth optimization in centralized WLANs for different traffic types

Allocating bandwidth between different forms of coexisting traffic (such as web-browsing, streaming, and telephony) within a wireless LAN is a challenging and interesting problem. Centralized coordination functions in wireless LANs offer several advantages over distributed approaches, having the benefit of a system overview at the controller, but obtaining a stable configuration of bandwidth allocation for the system is nontrivial. We present, review, and compare different mechanisms to achieve this end, and a number of different means of obtaining the configurations themselves. We describe an analytical model of the system under consideration and present two mathematical approaches to derive solutions for any system configuration and deployment, along with an adaptive feedback-based solution. We also describe a comprehensive simulation-based model for the problem, and a prototype that allows comparison of these approaches. Our investigations demonstrate that a self-adaptive dynamic approach far outperforms any static scheme, and that using a mathematical model to produce the configurations themselves confers several advantages.

Towards Integrated Wireless Systems: Inter-Mode Monitoring Techniques

Inter-operation between the heterogeneous wireless networks and systems available now and in the future is of considerable interest. Fundamental to such work is the ability to discover available alternative systems, and to monitor these modes to determine whether they are more attractive in some way than the current system. This paper presents a survey of different solutions to the problem of multi-mode detection and monitoring including blind unassisted techniques, co-operative devicefederation approaches and higher-layer mechanisms and suggests future research directions in this area.