A communication infrastructure is an essential part to the success of the emerging smart grid. A scalable and pervasive communication infrastructure is crucial in both construction and operation of a smart grid. In this paper, we present the background and motivation of communication infrastructures in smart grid systems. We also summarize major requirements that smart grid communications must meet. From the experience of several industrial trials on smart grid with communication infrastructures, we expect that the traditional carbon fuel based power plants can cooperate with emerging distributed renewable energy such as wind, solar, etc, to reduce the carbon fuel consumption and consequent green house gas such as carbon dioxide emission. The consumers can minimize their expense on energy by adjusting their intelligent home appliance operations to avoid the peak hours and utilize the renewable energy instead. We further explore the challenges for a communication infrastructure as the part of a complex smart grid system. Since a smart grid system might have over millions of consumers and devices, the demand of its reliability and security is extremely critical. Through a communication infrastructure, a smart grid can improve power reliability and quality to eliminate electricity blackout. Security is a challenging issue since the on-going smart grid systems facing increasing vulnerabilities as more and more automation, remote monitoring/controlling and supervision entities are interconnected.

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1315&context=electricalengineeringfacpub

A Survey on Smart Grid CommunicationInfrastructures: Motivations, Requirements andChallenges

Featuring direct communications between two user equipments (UEs) without signal relay through a base station, 3GPP sidelink transmissions have manifested their crucial roles in the Long-Term Evolution (LTE) Advanced (LTE-A) for public safety and vehicle-to-everything (V2X) services. With this successful development in LTE-A, the evolution of sidelink transmissions continues in 3GPP New Radio (NR), which renders sidelink an inevitable component as well as downlink and uplink. Targeting at offering low latency, high reliability and high throughout V2X services for advanced driving use cases, a number of new sidelink functions not provided in the LTE-A are supported in NR, including the feedback channel, grant-free access, enhanced channel sensing procedure, and new control channel design. To fully comprehend these new functions, this paper therefore provides essential knowledge of 3GPP NR sidelink transmissions, including the physical layer structure, resource allocation mechanisms, resource sensing and selection procedures, synchronization, and quality-of-service (QoS) management. Furthermore, this paper also provides performance evaluation to assess the gains brought from the new control channel design. As NR sidelink transmissions have been regarded as a foundation to provide advanced services other than V2X in future releases (e.g., advanced relay), potential enhancements are also discussed to serve the urgent demand in corresponding normative works.

/pdf/3gpp-nr-sidelink-transmissions-toward-5g-v2x-3pvqcr7v82.pdf

3GPP NR Sidelink Transmissions Toward 5G V2X

Powering cellular base stations with renewable energy are one of the long-term strategies for achieving green networks and reducing their operational costs. As an energy provider, the power grid is evolving into a smarter one, which allows more energy-efficient cellular networks and enables cooperation and interaction with the smart grid. On one hand, cellular networks can use harvested renewable energy and on-site energy storage to reduce their energy costs. On the other hand, the price of electricity depends on the energy load, which will eventually contribute to decreasing the peak consumption and global energy cost. In this paper, we propose new integration architecture for renewable energy-powered cellular networks and the smart grid. The proposed architecture is designed based on the classification and the analysis of the existing proposals and the requirements of the smart grid, renewable energy systems, and cellular networks.

Integrating Cellular Networks, Smart Grid, and Renewable Energy: Analysis, Architecture, and Challenges

Toward optimal participant decisions with voting-based incentive model for crowd sensing

The ability to perform device-to-device (D2D) communication in Long Term Evolution (LTE)-based cellular networks became possible with the introduction of Proximity Services (ProSe) functionalities in the 3rd Generation Partnership Program (3GPP) specifications. In this paper, we provide a description of the ProSe implementation that extends the LTE model already available in ns-3. Our model contains key features defined in LTE Release 12 and further enhanced in LTE Release 13 related to synchronization, discovery, and communication. We also provide validation of each feature by comparing simulation results with analytical models developed as part of our work on D2D communication.

/pdf/implementation-and-validation-of-an-lte-d2d-model-for-ns-3-21arkgqkbk.pdf

Implementation and Validation of an LTE D2D Model for ns-3

One of the most promising techniques to drastically reduce the energy consumption of cellular networks is the use of sleep-mode (SM) methods: when the traffic load is low, some components of the network, such as a base station (BS), can be switched off. In this case, the traffic load is managed by BSs that stay on . In this paper, we investigate how user cooperation can further reduce the energy consumption of a cellular network that uses SM strategies. In particular, we study how sleeping periods can be extended when users tolerate a delay before the start of their service. We propose two delay-tolerant-user-aware SM strategies and provide mathematical grounds for the evaluation of their performance. We evaluate the strategies in the context of LTE networks with realistic daily traffic patterns. The results show considerable daily energy reductions (up to 21% compared to the always- on paradigm and up to 15% compared to the SM strategy without user cooperation).

Reducing the Energy Footprint of Cellular Networks with Delay-Tolerant Users

Traditionally cellular networks have been dimensioned for providing seamless coverage and meeting the user demand with little regard to their energy consumption. Recently, the focus has been moved to seeking ways to increase the energy efficiency by better adapting to the existing users behaviors. In this paper, we are going a step further in studying a new type of disruptive service by trying to answer the question “What are the potential energy efficiency gains if some of the users are willing to tolerate delays?”. We present an analytical model of the energy usage of LTE base stations, which provides lower bounds of the possible energy gains under a decentralized, non-cooperative setup. The model is analyzed in six different scenarios (such as micro-macro cell interaction and coverage redundancy) for varying traffic and user-tolerable delays. We show that it is possible to reduce the power consumption by up to 30%.

Energy efficient cellular networks in the presence of delay tolerant users

The UE-to-Network Relay functionality was introduced to Long Term Evolution (LTE) cellular networks by the 3rd Generation Partnership Project (3GPP) in Release 13. In this technology, User Equipment (UEs) acting as Relay UEs are used to extend network coverage to cell-edge and out-of-coverage Remote UEs. One important part of this functionality is direct discovery, which is used by the Remote UEs willing to reach the network to detect the Relay UEs in proximity that can provide the desired connectivity service. In this paper, we study this protocol considering both discovery models defined in the LTE standard, and we develop analytical models to characterize the average time a Remote UE takes to discover a Relay UE using each discovery model. We validate the analytical models using system level simulations and we study the sensitivity of the metrics to different parameters of the protocol and number of UEs involved in the UE-to-Network Relay discovery.

UE-to-Network Relay Discovery in ProSe-enabled LTE Networks

Recently, energy behaviour is being considered as an important key performance indicator when studying mobile networks. Reducing their operational cost is becoming more essential due to the huge increase of traffic accompanied by the increase in the electric bills. In this paper, we are going a step forward to study the possibility of a new type of energy behaviour of renewable energy-powered base stations in the Smart Grid environment. We use renewable energy and energy storage and we employ the concept of delay tolerant users to provide ancillary services to the Smart Grid. Based on real data from the French power grid, results show that the achieved profit from providing ancillary services exceeds the electric bill and leads to a negative energy operational cost.

Samantha Gamboa

Papers

Implementation and Validation of an LTE D2D Model for ns-3

Reducing the Energy Footprint of Cellular Networks with Delay-Tolerant Users

Energy efficient cellular networks in the presence of delay tolerant users

UE-to-Network Relay Discovery in ProSe-enabled LTE Networks

The Smart Grid and Future Mobile Networks: Integrating Renewable Energy Sources and Delay Tolerant Users