Ziming Zhu

Smart Grid Communications: Overview of Research Challenges, Solutions, and Standardization Activities

Optimization of energy consumption in future intelligent energy networks (or Smart Grids) will be based on grid-integrated near-real-time communications between various grid elements in generation, transmission, distribution and loads. This paper discusses some of the challenges and opportunities of communications research in the areas of smart grid and smart metering. In particular, we focus on some of the key communications challenges for realizing interoperable and future-proof smart grid/metering networks, smart grid security and privacy, and how some of the existing networking technologies can be applied to energy management. Finally, we also discuss the coordinated standardization efforts in Europe to harmonize communications standards and protocols.

An integer linear programming based optimization for home demand-side management in smart grid

We propose a consumption scheduling mechanism for home area load management in smart grid using integer linear programming (ILP) technique. The aim of the proposed scheduling is to minimise the peak hourly load in order to achieve an optimal (balanced) daily load schedule. The proposed mechanism is able to schedule both the optimal power and the optimal operation time for power-shiftable appliances and time-shiftable appliances respectively according to the power consumption patterns of all the individual appliances. Simulation results based on home and neighbourhood area scenarios have been presented to demonstrate the effectiveness of the proposed technique.

Overview of demand management in smart grid and enabling wireless communication technologies

There are significant challenges as well as great opportunities for research at both policy and technology levels on the efficient use of energy. Most existing power generation and distribution systems are based on a century old mechanism where power grids are managed by vertically integrated utilities. Intelligent power grids known as smart grids are required as the demand for energy continues to grow and more and more emphasis is being placed on the supply of renewable energy. The main ingredient of smart grids is the integration of information and communication technology (ICT) into the grids to monitor and regulate power generation and demand. This article provides an overview of demand management with a particular focus on the necessary enabling wireless technologies. Various mechanisms and algorithms for the optimal demand management in smart grids using these wireless technologies are also reviewed.

An integer linear programming and game theory based optimization for demand-side management in smart grid

We propose a consumption scheduling mechanism for home and neighbourhood area load demand management in smart grid using integer linear programming (ILP) and game theory. The proposed mechanism is able to schedule both the optimal power and the optimal operation time for power-shiftable appliances and time-shiftable appliances respectively according to the power consumption patterns of all the individual appliances. Simulation results for both the centralised and the distributed management scenarios have been presented to demonstrate and verify the effectiveness of the proposed technique.

Eigenvalue and Support Vector Machine Techniques for Spectrum Sensing in Cognitive Radio Networks

Cognitive radio has been described as the panacea to the problem of ever growing demand and scarcity of the radio spectrum. Fundamental to the successful implementation of cognitive radio is spectrum sensing. Here, we propose and investigate the performance of eigenvalue and support vector machine (SVM) based learning approach for spectrum sensing in multi-antenna cognitive radios. The simulation results show that the proposed technique is capable of yielding detection probability of ≥ 90% at the signal-to-noise ratio (SNR) of -20 dB while maintaining the false alarm probability at ≤ 0%.

Data offloading method for interference and mobility management in femtocell systems

In this paper we propose an efficient operation mechanism of interference mitigation and mobility management. The main idea is to schedule radio resources between macrocell and femtocell base stations and pass the desired packet data through a femtocell base station without handover/access to the CSG (closed subscriber group) femtocell. The key benefit of this proposed mechanism is to achieve highly efficient mobility by enabling a CSG femtocell base station to relay data without handover and access to the CSG femtocell, avoiding potential interference and saving radio resource and signaling load on the network. Simulation results have been presented to demonstrate the benefits of the proposed scheme.

A Mean Field Game Theoretic Approach to Electric Vehicles Charging

Electric vehicles (EVs) provide environmentally friendly transport and they are considered to be an important component of distributed and mobile electric energy storage and supply system. It is possible that EVs can be used to store and transport energy from one geographical area to another as a supportive energy supply. Electricity consumption management should consider carefully the inclusion of EVs. One critical challenge in the consumption management for EVs is the optimization of battery charging. This paper provides a dynamic game theoretic optimization framework to formulate the optimal charging problem. The optimization considers a charging scenario where a large number of EVs charge simultaneously during a flexible period of time. Based on stochastic mean field game theory, the optimization will provide an optimal charging strategy for the EVs to proactively control their charging speed in order to minimize the cost of charging. Numerical results are presented to demonstrate the performance of the proposed framework.

Interference management in femtocell networks

Recently, smaller cells such as femtocells have been proposed to address the cellular coverage problem and provide a ‘greener’ solution to future high-speed wireless access. On the other hand, interference is a serious problem that could impact the wide deployment of femtocells. The contributions of this paper are threefold. First, we focus on the trade-off between energy efficiency and system performance. With realistic long-term evolution system parameters, we have shown that femtocells can indeed improve energy efficiency of the network. However, this comes with a price—performance degradation due to interference, which is especially severe in densely deployed scenarios. Second, we propose a proactive approach to handover and access management in femtocell systems, focusing especially on the interference issue of closed subscriber group femtocells. Third, we propose an efficient data offloading mechanism for interference mitigation and mobility management, with the aim to avoid potential interference and save radio resources and signalling load in the network. Simulation results have been presented to demonstrate the benefits of the proposed schemes. Copyright

Secure Real-Time Monitoring and Management of Smart Distribution Grid Using Shared Cellular Networks

Electricity production and distribution is facing two major changes. First, production is shifting from classical energy sources such as coal and nuclear power toward renewable resources such as solar and wind. Second, consumption in the low voltage grid is expected to grow significantly due to the expected introduction of electrical vehicles. The first step toward more efficient operational capabilities is to introduce an observability of the distribution system and allow for leveraging the flexibility of end connection points with manageable consumption, generation, and storage capabilities. Thanks to advanced measurement devices, management framework, and secure communication infrastructure developed in the FP7 SUNSEED project, the distribution system operator (DSO) now has full observability of the energy flows in the medium/low voltage grid. Furthermore, the prosumers are able to participate pro-actively and coordinate with the DSO and other stakeholders in the grid. The monitoring and management functionalities have strong requirements for communication latency, reliability, and security. This article presents novel solutions and analyses of these aspects for the SUNSEED scenario, where smart grid ICT solutions are pr

Distributed Caching in Wireless Cellular Networks Incorporating Parallel Processing

Distributed caching is a promising technique for reducing redundant data traffic and user content access delay in telecommunications systems. This article explores caching technologies with a focus on the processing of content requests in todays hierarchical wireless cellular networks. The authors observed that, as the number of caches at different layers of the network increases, the disadvantage of the hierarchical architecture in terms of processing delay gradually emerges. They introduce a parallel-processing strategy in order to improve the efficiency of cache servers. Theoretical analysis and numerical simulations show the potential of the proposed scheme in terms of reducing both the content access delay and redundant data traffic in the core network. The authors also carry out cost assessments for the proposed scheme. Future research on related technologies is discussed at the end of this article.