Robert C. Atkinson

Estimation of Impulsive Noise in an Electricity Substation

Measurements of impulsive noise in a 400/275/132-kV electricity substation are presented. The measurements are made with three antennas having overlapping bands covering the range 100 MHz-6 GHz. This range includes those bands relevant to modern wireless local area network and wireless personal area network technologies (e.g., IEEE 802.11a/b/g and IEEE 802.15.1/4), which, if proved to be sufficiently robust in the presence of impulsive noise, could play a useful role in substation monitoring and control. Impulsive events are extracted from the measured data using the wavelet packet transform, and the statistical distributions of pulse rate, pulse amplitude, pulse duration, and pulse rise time are presented. An unexpected quasi-periodic component of the noise is observed.

An Advanced SOM Algorithm Applied to Handover Management Within LTE

A novel approach to handover management for Long-Term Evolution (LTE) femtocells is presented. Within LTE, the use of self-organizing networks (SONs) is included as standard, and handover management is one of its use cases. Base stations can autonomously decide whether handover should take place and assign the values of relevant parameters. Due to the limited range of femtocells, handover requires more delicate attention in an indoor scenario to allow for efficient and seamless handover from indoor femtocells to outdoor macrocells. As a result of the complexity of the indoor radio environment, frequent ping-pong handovers between the femtocell and macrocell layers can occur. A novel approach requiring a small amount of additional processing using neural networks is presented. A modified self-organizing map (SOM) is used to allow a femtocell to learn the locations of the indoor environment from where handover requests have occurred and, based on previous experience, decide whether to permit or prohibit these handovers. Once the regions that coincide with unnecessary handovers have been detected, the algorithm can reduce the total number of handovers that occur by up to 70% while still permitting any necessary handover requests to proceed. By reducing the number of handovers, the overall efficiency of the system will improve as the consequence of a reduction in associated but unnecessary signaling. Using machine learning for this task complies with the plug-and-play functionality required from SONs in LTE systems.

The personnel distributed environment

Beyond 3G continues to dominate discussion within the cellular community. A variety of issues are being actively debated: the requirement for a new air interface, greater interworking with WLANs and other networks, a service-driven approach, and potential for increasing market penetration of network-enabled devices. The Mobile VCE vision for beyond 3G encompasses a world that has embraced a disparate range of networked processing and communications devices. This article presents an architecture for user-centric communication across heterogeneous access networks

Threat analysis of IoT networks using artificial neural network intrusion detection system

The Internet of things (IoT) is still in its infancy and has attracted much interest in many industrial sectors including medical fields, logistics tracking, smart cities and automobiles. However as a paradigm, it is susceptible to a range of significant intrusion threats. This paper presents a threat analysis of the IoT and uses an Artificial Neural Network (ANN) to combat these threats. A multi-level perceptron, a type of supervised ANN, is trained using internet packet traces, then is assessed on its ability to thwart Distributed Denial of Service (DDoS/DoS) attacks. This paper focuses on the classification of normal and threat patterns on an IoT Network. The ANN procedure is validated against a simulated IoT network. The experimental results demonstrate 99.4% accuracy and can successfully detect various DDoS/DoS attacks.

Vulnerability of Zigbee to impulsive noise in electricity substations

The vulnerability of Zigbee technology to noise in an electricity substation environment is assessed. Substation noise obtained from a measurement campaign is modelled as a Symmetric α-Stable process. The parameters of the model are estimated from the measurements and the resulting model is used to investigate the likely BER performance of Zigbee technology deployed in a substation.

QoS-Aware Network-supported Architecture to Distribute Application Flows over Multiple Network Interfaces for B3G Users

Users in the Beyond-Third-Generation (B3G) wireless system expect to receive ubiquitous communication services with customised quality-of-service (QoS) commitments for different applications, preferably in a way as transparent as possible. Ideally, flows belonging to diverse applications can be automatically and optimally distributed (or handed off) among the most appropriate access networks for multihomed users. To contribute to realising this vision, we propose a novel architecture to achieve QoS-aware policy-based flow handoffs for multihomed users, especially those equipped with more than a single personal device. In this architecture, advanced network intelligence enables a personal gateway to handle flow distributions dynamically for all the devices behind it according to the applications’ QoS requirements and the current available network resources. The essential procedures in this architecture are described. Following that, the flow handoff delay is analysed and numerical results are illustrated. To prove the proposed concepts, up-to-date implementations with experimental results are also presented.

Channel estimation and transmit power control in wireless body area networks

Wireless body area networks have recently received much attention because of their application to assisted living and remote patient monitoring. For these applications, energy minimisation is a critical issue since, in many cases, batteries cannot be easily replaced or recharged. Reducing energy expenditure by avoiding unnecessary high transmission power and minimising frame retransmissions is therefore crucial. In this study, a transmit power control scheme suitable for IEEE 802.15.6 networks operating in beacon mode with superframe boundaries is proposed. The transmission power is modulated, frame-by-frame, according to a run-time estimation of the channel conditions. Power measurements using the beacon frames are made periodically, providing reverse channel gain and an opportunistic fade margin, set on the basis of prior power fluctuations, is added. This approach allows tracking of the highly variable on-body to on-body propagation channel without the need to transmit additional probe frames. An experimental study based on test cases demonstrates the effectiveness of the scheme and compares its performance with alternative solutions presented in the literature.

Design and evaluation of flow handoff signalling for multihomed mobile nodes in wireless overlay networks

With the increasing deployment of wireless overlay networks, a mobile node with a range of network interfaces can be connected to multiple heterogeneous or homogeneous access networks simultaneously. Such host multihoming technology can be exploited to distribute (or hand off) application flows among the most appropriate interfaces and access networks dynamically to achieve end-to-end seamless, robust and even quality-of-service-aware communications for mobile users. It is essential that an efficient and effective flow handoff signalling scheme be in place. Nevertheless, little prior work has addressed this problem sufficiently in a systematic way and little performance evaluation is readily available. We propose a set of signalling procedures for a comprehensive, flexible yet standard-oriented flow handoff solution. Two candidate schemes are designed by extending and optimising related IETF work based on Mobile IPv6 or Network Mobility (NEMO). Theoretical analyses are performed and numerical results are then presented with a focus on signalling loads to compare the two proposals and to demonstrate that the designs can largely meet the requirements on desired signalling performance. Preliminary implementations and experimental results are also reported to validate the concepts of the designs, investigate the flow handoff signalling delays and verify the effectiveness of the policy-based flow handoff support for typical real-time and non-real-time applications.

A mobility framework to improve heterogeneous wireless network services

We propose and investigate the Internet Protocol version 6 (IPv6) enabled mobility framework to improve the user mobility experience in heterogenous wireless networks. The framework considers the traditional IP network infrastructure, IPv6 based mobility support, multihoming, traffic flow transparent handovers and flat/dynamic mobility policy enforcement to guarantee the Quality of Service (QoS) and Quality of Experience (QoE) with ubiquitous connectivity. Using Network Mobility (NEMO) we can provide a flexible network integration mechanism across WiFi, WiMax and UMTS systems vertically. The flexible approach overcomes the limitation of different networks access denial when nodes move using two operations: Policy enforced handover management and Dynamic handover implementation. The paper describes the design rationale behind the solution, introduces an experimental testbed and simulation models, validates mobility related services performance, and discusses our research findings.

Laboratory Assessment of WLAN Performance Degradation in the Presence of Impulsive Noise

A laboratory test to assess the impact of impulsive noise on the performance of WLAN equipment is described. The test is put in the context of a larger programme of work to assess the performance and reliability of wireless equipment subject to partial discharge noise in high voltage electricity supply substations. The character of partial discharge and WLAN technology are briefly reviewed. The laboratory test methodology is reported and some preliminary results are presented. A related forthcoming field-trial for tests of WLAN equipment in a 275/400 kV air-insulated substation is briefly described.