The smart grid is conceived of as an electric grid that can deliver electricity in a controlled, smart way from points of generation to active consumers. Demand response (DR), by promoting the interaction and responsiveness of the customers, may offer a broad range of potential benefits on system operation and expansion and on market efficiency. Moreover, by improving the reliability of the power system and, in the long term, lowering peak demand, DR reduces overall plant and capital cost investments and postpones the need for network upgrades. In this paper a survey of DR potentials and benefits in smart grids is presented. Innovative enabling technologies and systems, such as smart meters, energy controllers, communication systems, decisive to facilitate the coordination of efficiency and DR in a smart grid, are described and discussed with reference to real industrial case studies and research projects.

Demand response and smart grids—A survey

This document provides updates to IEEE Std 802.16's MIB for the MAC, PHY and asso- ciated management procedures in order to accommodate recent extensions to the standard.

IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems Draft Amendment: Management Information Base Extensions

With the explosive growth of mobile data demand, the fifth generation (5G) mobile network would exploit the enormous amount of spectrum in the millimeter wave (mmWave) bands to greatly increase communication capacity. There are fundamental differences between mmWave communications and existing other communication systems, in terms of high propagation loss, directivity, and sensitivity to blockage. These characteristics of mmWave communications pose several challenges to fully exploit the potential of mmWave communications, including integrated circuits and system design, interference management, spatial reuse, anti-blockage, and dynamics control. To address these challenges, we carry out a survey of existing solutions and standards, and propose design guidelines in architectures and protocols for mmWave communications. We also discuss the potential applications of mmWave communications in the 5G network, including the small cell access, the cellular access, and the wireless backhaul. Finally, we discuss relevant open research issues including the new physical layer technology, software-defined network architecture, measurements of network state information, efficient control mechanisms, and heterogeneous networking, which should be further investigated to facilitate the deployment of mmWave communication systems in the future 5G networks.

A survey of millimeter wave communications (mmWave) for 5G: opportunities and challenges

Cognitive radio (CR) is the enabling technology for supporting dynamic spectrum access: the policy that addresses the spectrum scarcity problem that is encountered in many countries. Thus, CR is widely regarded as one of the most promising technologies for future wireless communications. To make radios and wireless networks truly cognitive, however, is by no means a simple task, and it requires collaborative effort from various research communities, including communications theory, networking engineering, signal processing, game theory, software-hardware joint design, and reconfigurable antenna and radio-frequency design. In this paper, we provide a systematic overview on CR networking and communications by looking at the key functions of the physical (PHY), medium access control (MAC), and network layers involved in a CR design and how these layers are crossly related. In particular, for the PHY layer, we will address signal processing techniques for spectrum sensing, cooperative spectrum sensing, and transceiver design for cognitive spectrum access. For the MAC layer, we review sensing scheduling schemes, sensing-access tradeoff design, spectrum-aware access MAC, and CR MAC protocols. In the network layer, cognitive radio network (CRN) tomography, spectrum-aware routing, and quality-of-service (QoS) control will be addressed. Emerging CRNs that are actively developed by various standardization committees and spectrum-sharing economics will also be reviewed. Finally, we point out several open questions and challenges that are related to the CRN design.

Cognitive radio networking and communications: an overview

Millimeter wave (mmWave) communications have recently attracted large research interest, since the huge available bandwidth can potentially lead to the rates of multiple gigabit per second per user Though mmWave can be readily used in stationary scenarios, such as indoor hotspots or backhaul, it is challenging to use mmWave in mobile networks, where the transmitting/receiving nodes may be moving, channels may have a complicated structure, and the coordination among multiple nodes is difficult To fully exploit the high potential rates of mmWave in mobile networks, lots of technical problems must be addressed This paper presents a comprehensive survey of mmWave communications for future mobile networks (5G and beyond) We first summarize the recent channel measurement campaigns and modeling results Then, we discuss in detail recent progresses in multiple input multiple output transceiver design for mmWave communications After that, we provide an overview of the solution for multiple access and backhauling, followed by the analysis of coverage and connectivity Finally, the progresses in the standardization and deployment of mmWave for mobile networks are discussed

Millimeter Wave Communications for Future Mobile Networks

For practical use of a wireless communication in the TV white-space, a variety of technologies such as IEEE 802.11af have been widely proposed and researched. In this study, we propose a UHF converter which enables the wireless communication in the UHF band with an existing WLAN module by converting its frequency band from 2.4 GHz to UHF. Also, we have prototyped a small UHF converter which can be implemented in a tablet terminal and its RF performance and spurious response are characterized.

Prototype of UHF converter for TV white-space utilization

Unlike most general wireless users enjoying broadband access to the Internet and so on, a number of mission-critical applications such as PPDR are using narrowband systems that are only capable of transmitting voice and low-rate data. Broadband wireless networks with greater reliability are increasingly demanded by these applications including the emerging Smart Grid. With this vision, the IEEE 802.16 Working Group completed two standard amendments recently, IEEE Std 802.16n-2013 and IEEE Std 802.16.1a-2013. 802.16 network reliability is significantly increased by technical developments dealing with failures of network infrastructure stations, radio path and backhaul connectivity, and so on. This article serves to analyze the envisaged typical use cases of greater reliable broadband wireless networks, outline the main technical developments of the two standards, and introduce a recently developed practical system for PPDR applications in Japan.

Greater reliability in disrupted metropolitan area networks: use cases, standards, and practices

In this paper, we describe the design challenges of a recently developed television white space (TVWS) device prototype and how those were resolved. The prototype, which includes the following components: a cognitive management entity (CME), a sensing module, a geolocation device, a TV band database, a transmitter and a receiver, was designed to take part in Singapore TVWS test trial. The major features the prototype has are: cognitive functionality, spectrum sensing and database access. The technical challenges faced during its development are described in terms of wide dynamic range, adjacent channel rejection and synchronization issues of the spectrum sensor, baseband vs intermediate frequency based sensing, non white environmental noise, security regarding database access and troubles inherent in wireless environment. Performance of the prototype is also presented in terms of cognitive operations such as, success of TV signals and other incumbent detection through database access and sensing, time required for database access, sensing, channel selection, channel switching etc. Discussion regarding setting a reasonable sensing target is also presented.

Design Aspects of a Television White Space Device Prototype

This paper describes the challenges of frequency channel selection for WLANs operating in the TV White Space (TVWS) and proposes a dynamic frequency selection (DFS) technique as a solution. Based on the statistics gained from past usage experience of channels, of the TVWS channels' vacancies and channel occupation by the adjacent WLANs, each WLAN evaluates and prioritize the channels independently using a priority function. Then by selecting the channel of the highest priority among vacant channels, each WLAN can quickly find a channel in the low interference regime and whose vacancy is adaptive to its traffic load distribution as well. Performance of the proposed DFS is evaluated through simulation using QualNet, based on TVWS channels with realistic feature and by setting the weight factors of different metrics in the priority function to different values. The evaluation results show that compared to conventional DFS, the proposed DFS avoids adjacent APs selecting the same channel and reduces channel switch rate, and is more adaptive to diverse environments. As a consequence, it maximally reduces total time consumption of channel switch by 40% than random selection.

Autonomous Dynamic Frequency Selection for WLANs Operating in the TV White Space

PROBLEM TO BE SOLVED: To provide a radio communication system capable of preventing interference even when a network including a secondary user coexists, and the like. SOLUTION: The radio communication system includes a primary user belonging to a first network, a first secondary user belonging to a second network, and a coexistence manager (CM). The coexistence manager (CM) acquires information related to a spectrum hole without being at least temporarily used by the primary user. The coexistence manager (CM) determines whether interference occurs in the first network by usage of the spectrum hole by the first secondary user. When interference occurs as a result of the determination, the occurrence of the interference is reported to a second secondary user belonging to a third network different from the second network. COPYRIGHT: (C)2011,JPO&INPIT

Hiroshi Harada

Papers

Prototype of UHF converter for TV white-space utilization

Greater reliability in disrupted metropolitan area networks: use cases, standards, and practices

Design Aspects of a Television White Space Device Prototype

Autonomous Dynamic Frequency Selection for WLANs Operating in the TV White Space

Radio communication system, coexistence manager installed in the system, and radio communication method