A smart grid is the next-generation electric grid that enables efficient, intelligent, and economical power generation as well as reliable, safe, robust transmission and distribution. It uses modern information and communications technologies, such as advanced sensing, monitoring and processing technology, and high-speed bi-directional communications and networking. In recent years, the smart grid has attracted significant attentions from academics, industry, equipment manufacturers, and service providers. Developing the smart grid has become a global trend due to the immense potential benefits including enhanced reliability and resilience, higher operational efficiency, more efficient energy consumption, and better power quality.

We received strong responses to this call for papers on Recent Advances in Smart Grid from universities, research institutes, and industry. Following a peer-review process, we have selected five papers for inclusion in this special issue.

The first paper,“Theory Study and Application of the BP-ANN Method for Power Grid Short-Term Load Forecasting,”aims at improving the accuracy of short-term load forecasting in a power system. To this end, the authors propose a new predictive model using the BP-ANN-based method from a neural network. A theoretical background and numerical results are also given in this paper.

The second paper,“A Solution-Based Analysis of Attack Vectors on Smart Home Systems,”first presents a short survey of privacy and security in the broader smartworld context and then analyzes and ranks attack vectors or entry points into a smart home system and propose solutions to remedy or diminish the risk of compromised security or privacy.

In the third paper,“Secure Communication Networks in the Advanced Metering Infrastructure of Smart Grid,”the authors propose a security protocol for the advanced metering infrastructure (AMI) with two-way communication in a smart grid. The work proposes a security protocol specifically for the AMI to meet the security requirements.

The methods for efficient network resource management are proposed in the fourth paper,“Reliable Remote Relay Protection in Smart Grid.”The authors discuss simple backup solutions in the previous work. They also focus on improving the system reliability by exploring known power system information and minimizing the chances of false trips of important remote relays. Moreover, in order to further improve the system reliability, the authors investigate the peer-to-peer protection approaches to address the single point of failure of centralized control center.

The authors of the final paper,“Experimental Study on Cloud-Computing-Based Electric Power SCADA System,”discuss the main issues in applying private cloud architecture to power system control and propose a professional private cloud solution to integrate the electric power SCADA system. In particular, experimental study has been conducted.

We would also take this opportunity to thank all the authors, reviewers, and editors in ZTE involved in this special issue.

Software-defined networks (SDN) have attracted much attention recently because of their flexibility in terms of network management. Increasingly, SDN is being introduced into wireless networks to form wireless SDN. One enabling technology for wireless SDN is network virtualization, which logically divides one wireless network element, such as a base station, into multiple slices, and each slice serving as a standalone virtual BS. In this way, one physical mobile wireless network can be partitioned into multiple virtual networks in a software-defined manner. Wireless virtual networks comprising virtual base stations also need to provide QoS to mobile end-user services in the same context as their physical hosting networks. One key QoS parameter is delay. This paper presents a delay model for software-defined wireless virtual networks. Network calculus is used in the modelling. In particular, stochastic network calculus, which describes more realistic models than deterministic network calculus, is used. The model enables theoretical investigation of wireless SDN, which is largely dominated by either algorithms or prototype implementations.

Software - defined networking (SDN) is a promising technology for next-generation networking and has attracted much attention from academics, network equipment manufacturer, network operators, and service providers. It has found applications in mobile, data center, and enterprise networks. The SDN architecture has a centralized, programmable control plane that is separate from the data plane. SDN also provides the ability to control and manage virtualized resources and networks without requiring new hardware technologies. This is a major shift in networking technologies.
The ITU-T has been engaged in SDN standardization, and the European Telecommunications Standard Institute (ETSI) has been working on network function virtualization (NFV), which complements SDN. The Open Network Foundation (ONF) is a non-profit organization dedicated to promoting the adoption of open SDN. Recently, much work has been done on SDN to meet future network requirements.
Network virtualization creates multiple virtual infrastructures within a deployed infrastructure. These virtualized infrastructures can be created over a single physical infrastructure. Each virtual network can be isolated from each other and programmed to meet user requirements in terms of resource functionality and capacity. This ensures that appropriate network resources are provided to the user.
The SDN framework includes programmable control plane, data-forwarding plane abstraction, and methods to map the virtualized infrastructures onto the underlying physical network infrastructure.
Key issues to be addressed are network resource isolation, network abstraction, topology awareness, quick reconfigurability, performance, programmability, management, mobility, security, and wireless network access.
We received strong response to this call for papers on SDN from network operators, equipment manufacturers, universities, and research institutes. Following a peer-review process, we selected nine papers for inclusion in this special issue.
The first paper,“Network Function Virtualization Technology: Progess and Standardization”discusses the main challenges in SDN faced by network carriers. This paper also discusses current standardization activities and research on NFV related to SDN.
The second paper,“Service Parameter Exposure and Dynamic Service Negotiation in SDN Environments,”discusses the ability of SDN to facilitate dynamic provisioning of network services. The paper focuses on two main aspects of the SDN framework: network abstraction and dynamic parameter exposure and negotiation.
The third paper,“SDN-Based Broadband Network for Cloud Services,”discusses how SDN/NFV will be vital for constructing cloud-oriented broadband infrastructure, especially within data center networks and for interconnecting between data center networks. The authors propose SDN/NFV in broadband access to realize a virtualized residential gateway.
The fourth paper,“D-ZENIC: A Scalable Distributed SDN Controller Architecture,”describes a solution to minimizing the cost of network state distribution. This solution is a network control platform called D-ZNEIC that supports distributed deployment and linear scale-out by trading off complexity for scalability.
The fifth paper,“Software-Defined Cellular Mobile Network Solutions,”describes current research on and solutions for software-defined cellular networks. It also discusses related specifications and possible research directions.
The sixth paper,“SDN-Based Data Offloading for 5G Mobile Networks,”describes an integrated 4G/Wi-Fi architecture evolved with SDN abstraction in the mobile backhaul and enhanced components that facilitate the move towards 5G.
The seventh paper,“Integrating IPsec Within OpenFlow Architecture for Secure Group Communication,”discusses Internet Protocol security (IPsec) in the context of OpenFlow architecture and SDN.
The eighth paper,“Virtualized Wireless SDNs: Modelling Delay Through the Use of Stochastic Network Calculus,”describes a delay model for a software-defined wireless virtual network with some theoretical investigation into wireless SDN.
The final paper,“Load Balancing Fat-Tree on Long-Lived Flows: Avoiding Congestions in Data Center Network,”describes a dynamic load-balancing algorithm for fat tree in the context of SDN architecture.