Woon Hau Chin

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.

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.

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.

Distributed beamforming and power allocation for cooperative networks

Cooperative diversity systems rely on using relay nodes to relay copies of transmitted information to the destination such that each copy experiences different channel fading, hence increasing the diversity of the system. However, without proper processing of the message at the relays, the performance of the cooperative system may not necessarily perform better than direct transmission systems. In this paper, we proposed a distributed beamforming and power allocation algorithm which substantially improves the diversity of the system with only very limited feedback from the destination node. We also derive outage probability as well as study the outage behavior of this scheme.

Radio resource management considerations for LTE Femto cells

Femtocell access points (FAPs), also popularly known as Home Base Stations, are small base stations for use within indoor environments to improve coverage and capacity. FAPs have a limited range (e.g. limited to a home or office area) but offer immense capacity improvements for the network due to the ability to reuse a frequency more often as a result of smaller coverage areas. Because there may be thousands of these devices and since the nature of deployment is adhoc, it may not be possible to carry out elaborate frequency planning like that in the traditional cellular network. This paper aims to outline the radio resource management considerations within the context of femto cells, the broader objective being to initiate a discussion and encourage research in the areas highlighted.

AF two-path half duplex relaying with inter-relay self interference cancellation: diversity analysis and its improvement

In this paper, we consider a network consisting of one source, one destination and two relays, under a half duplex constraint. We analyze an amplify-and-forward (AF) two-path relaying scheme where one of the relays additionally performs inter-relay interference cancellation. With this inter-relay self interference cancellation, we show that degradation in performance can be significantly reduced when inter-relay channel gain increases. By treating the AF two-path relaying as an equivalent MIMO space time code, we derive an upper bound for the pairwise error probability (PEP) of this system. Previous works indicate that only a diversity order of two can be achieved even though physically there are three possibly independent spatial paths to the destination. From our analysis of the PEP, we analytically prove and identify the reason to the limited diversity order of two. We then propose a simple but novel precoding scheme which allows the system to achieve a full diversity order of three while maintaining the spectral efficiency gain of the two-path relaying protocol. A robust precoding design to achieve full diversity order with high coding gain is also proposed.

Max-Min Antenna Selection for Bi-Directional Multi-Antenna Relaying

In this paper, we study the performance of bidirectional (two-way) communication system using two different broadcast schemes with network coding. We propose the use of Max-Min criteria for antenna selection with binary network coding and transmit beamformig without binary network coding. We derive and show that unlike traditional antenna selection with binary network coding scheme, the Max-Min Antenna Selection scheme can achieve full diversity order. Compared with transmit beamforming, Max-Min Antenna Selection achieves comparable performance but with less stringent requirements on the channel state information. Also its extension to distributed network of multiple-antenna relays is much easier than transmit beamforming relaying scheme.

Bi-Directional Multi-Antenna Relay Communications with Wireless Network Coding

In this paper, we consider a two-way or bi-directional communications system with a relay equipped with multiple antennas. We show that when the downlink channel state information is not known at the relay, the benefit of having additional antennas at the relay can only be obtained by using decode and forward (DF) but not amplify and forward (AF). The gain becomes significant when we employ transmit diversity together with wireless network coding. We also demonstrate how the performance of such system can be improved by performing antenna selection at the relay. Our results show that if downlink channel state information is known at the relay, network coding may not provide additional gain than simple antenna selection scheme.

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.