Wireless Neighborhood Area Network Research Articles

Demand side management with wireless channel impact in IoT-enabled smart grid system

Demand Side Management (DSM) is a vital issue in smart grids, given the time-varying user demand for electricity and power generation cost over a day. On the other hand, wireless communications with ubiquitous connectivity and low latency have emerged as a suitable option for smart grid. The design of any DSM system using a wireless network must consider the wireless link impairments, which is missing in existing literature. In this paper, we propose a DSM system using a Real-Time Pricing (RTP) mechanism and a wireless Neighborhood Area Network (NAN) with data transfer uncertainty. A Zigbee-based Internet of Things (IoT) model is considered for the communication infrastructure of the NAN. A sample NAN employing XBee and Raspberry Pi modules is also implemented in real-world settings to evaluate its reliability in transferring smart grid data over a wireless link. The proposed DSM system determines the optimal price corresponding to the optimum system welfare based on the two-way wireless communications among users, decision-makers, and energy providers. A novel cost function is adopted to reduce the impact of changes in user numbers on electricity prices. Simulation results indicate that the proposed system benefits users and energy providers. Furthermore, experimental results demonstrate that the success rate of data transfer significantly varies over the implemented wireless NAN, which can substantially impact the performance of the proposed DSM system. Further simulations are then carried out to quantify and analyze the impact of wireless communications on the electricity price, user welfare, and provider welfare.

Raptor-IRSA Grant-free Random Access protocol for smart grids applications

This paper deals with the reliability of random access (RA) protocols for massive wireless smart grid communication (m-SGC). We propose and analyze an improved grant-free RA (GF-RA) protocol for critical SG applications under strict QoS m-SGC requirements. At first, we discuss the main features of the SG neighborhood area network (NAN) architecture. We explore the main features of low-rate machine-type wireless networks, and also we describe a technology characterization of wireless neighborhood area networks (WNAN) in medium-range coverage applications. We propose a new-improved irregular repetition slotted ALOHA, combining Raptor codes and irregular ALOHA, namely RapIRSA random access protocol, to better respond to critical high-reliability QoS requirements under a 5G network perspective. Then, we compare and comprehensively analyze the proposed RapIRSA protocol with two existing RA protocols, the IRSA protocol, and the classical Slotted Aloha. Finally, We summarize the potential challenges in implementing the proposed RA protocol for SG critical applications considering a massive number of smart sensors (SS).

A Hierarchical Network with Fault Tolerance by a Multi-Factor Method for Neighborhood Area Network in Smart Grid.

The neighborhood area network of a smart grid usually has hierarchical wireless communication. Due to forwarding and processing more data, the upper-layer nodes are more likely to suffer congestion and energy exhaustion. This phenomenon leads to the failure of uploading data to the control center. To solve this problem, this paper proposes a scheme for constructing a multi-factor fault-tolerant hierarchical network. This scheme firstly defines a criterion for the generation of redundant links by multi-factor method in a hierarchical wireless network with the characteristics of the neighborhood area network. Then the redundant links are used to reconstruct the existing topology of the neighborhood area network for improving fault tolerance. Finally, a greedy routing algorithm is put forward to select a proper data transmission path by bypassing low energy nodes, further reducing the failure of uploading data to the control center. The simulation results show that the proposed scheme can effectively improve the fault tolerance of the network topology of the wireless neighborhood area network and balance the network energy consumption. Compared with the original scheme, the proposed scheme improves the fault tolerance by 35% and the relative transmission rate by 21%.

Технические принципы создания беспроводной локальной сети Wi-Fi

This article discusses the stages of development, characteristics of a wireless local area network Wi-Fi, options for its topology and equipment used. Currently, there are such different types of wireless networks as Wireless Wide Area Network, Wireless Metropolitan Area Networks (Wireless Neighborhood Area Network), Wireless Local Area Network, Wireless Personal Area Network. Each of the listed wireless networks has its own specific range and application. Wireless LAN Wi-Fi refers to the Wireless Local Area Network. The first wireless LAN standard, Wi-Fi, was approved in 1997. From the moment of their appearance to the present day, the following standards of this network have appeared: 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.11ad, 802.11ax. For each standard, the speeds and frequency ranges at which the data transmission was carried out are indicated, and the technologies on which they are built are described. Wireless LAN Wi-Fi has three topologies: 1) Ad-Hoc (point-to-point) or Independent Basic Service Set; 2) Basic Service Set ("client / server") and 3) Extended Service Set ("extended service areas"). To build a Wi-Fi network, network adapters, access points, routers, ADSL modems, Wi-Fi phones, Wi-Fi antennas, Wi-Fi repeaters are used. Wi-Fi adapters are used by devices that do not have a built-in Wi-Fi module. Wi-Fi access points are designed for organizing wireless access within a local network. Wi-Fi routers are designed to route traffic on a computer network. ADSL modems are used to access the Internet over a telephone line. Wi-Fi repeaters are used to expand the coverage of a wireless network using already installed equipment. Wi-Fi phones are wireless IP phones. Wi-Fi antennas are used to extend the range of a wireless network.

Generating Scale-Free Topology for Wireless Neighborhood Area Networks in Smart Grid

Neighborhood area networks (NANs) are critical infrastructure in smart grid to support communications. With the development of wireless communication technologies, there is a great potential for large-scale wireless-mesh NANs to be deployed to smart grid systems. While there exist theoretical models of complex networks, they are not directly applicable in the generation of network topology for wireless-mesh NANs due to their lack of some specifications unique in smart grid, leading to difficulties in theoretical studies of smart grid NANs. Among various topological structures, scale-free networks are considered as a potential resolution. This paper proposes a systematic approach to generate scale-free topology of wireless-mesh NANs in smart grid. A theoretical analysis confirms the scale-free feature of the network topology generated from the approach. To reveal the characteristics of our approach in comparison with widely used models of general complex networks, simulations are conducted on various network parameters including network diameter, average path length, clustering coefficient, and fractal dimension. The simulation results show that our approach for generating wireless-mesh NAN topology is fundamentally different from these compared models, and thus is a new type of complex-network model. Specifically, our model is suitable for wireless-mesh NANs in smart grid.

Constrained Broadcast With Minimized Latency in Neighborhood Area Networks of Smart Grid

Neighborhood area networks (NANs) are essential communication infrastructure in smart grid. They support communications for various applications including time-critical ones. A typical NAN communication scenario is to send commands from a control center simultaneously to a large number of nodes, demanding low-latency broadcast communications. This is challenging due to the limited bandwidth and large number of nodes in wireless NANs. While some broadcast schemes, e.g., opportunistic flooding, have been developed for general wireless sensor networks, they are not optimized for smart grid NANs with unique characteristics and low-latency requirements for time-critical applications. Therefore, a constrained broadcast scheme with minimized latency (CBS-ML) is presented in this paper for low-latency NAN communications. To avoid traffic congestion, it constrains the broadcast to a small number of core nodes. Theoretical developments are presented to show how to select core nodes based on network topology and link reliability. Simulations are conducted to demonstrate the proposed CBS-ML.

Provisioning required reliability of wireless data communication in smart grid neighborhood area networks

A possible candidate for implementing smart grid neighborhood area network (NAN) is wireless communications because of its advantages, such as flexibility and low installation and maintenance cost. However, one of the problems with wireless communication is its unreliability, whereas communication reliability is a basic requirement of smart grid applications. In this paper, we consider a wireless mesh network for NAN and then propose a method on the basis of hop-by-hop ARQ that achieves the required data communication reliability in wireless NAN and, at the same time, satisfies the communication latency constraint which is another requirement of smart grid applications. The proposed approach provides the optimal number of allowed retransmissions at each hop considering the loss probabilities of all hops and end-to-end delay constraint. Comparing to the typical application of ARQ in which the number of retransmissions permitted is the same at each hop, it is demonstrated that the proposed approach achieves a higher level of reliability while meeting the delay constraint. Moreover, the proposed method is evaluated by simulation, and the results are consistent with the results of the theoretical model.

Wireless Neighborhood Area Networks With QoS Support for Demand Response in Smart Grid

In order to support various innovative demand response programs, smart grid needs a wireless communication network with quality-of-service (QoS) support. This paper studies the issue of providing QoS in terms of packet delay, packet error probability, and outage probability to a large number of sensors and smart meters in a neighborhood area network of a densely populated urban area. We assume the network is based on the IEEE 802.15.4g Standard. Given that bandwidth is limited, we propose to divide smart meters into groups and each group will take a turn to access a shared wireless channel in a time-division-multiplexing manner. Within each allocated time duration, a group of smart meters will compete for channel access using a simple slotted Aloha protocol. We have developed an analytical model to quantify the QoS metrics. Through the analytical model, we can determine the minimum concentrator density that is required to support a given smart meter density. We have verified the analytical model through simulations. The results show that we need less than ten concentrators per km $^{2}$ to support a node density of 500 units per km $^{2}$ , while making sure that packet delay does not exceed 1.0 s, packet error probability is below 0.005 and outage probability is lower than 0.01.

Energy Efficient Self-Sustaining Wireless Neighborhood Area Network Design for Smart Grid

Neighborhood area network (NAN) is one of the most important sections in smart grid communications. It connects residential customers as part of a two-way communication infrastructure responsible for transmitting power grid sensing and measuring status, as well as the control messages. In this paper, we propose a cost-effective, flexible, and sustainable NAN design using wireless technologies such as IEEE 802.11s and IEEE 802.16, as well as renewable energy such as solar power. We propose an optimization problem to minimize total cost. To solve the problem, we also study the problem of selecting the optimal number of gateways in a NAN. Moreover, in order to achieve fairness for the customers and to meet the most critical latency requirements, we propose geographical deployment methods for gateway data aggregate points (DAPs). Different transmission power of each gateway DAP is also carefully determined for the fairness, as well as for the maximum power efficiency. Unlike other researches using game theoretical approaches in multiaccess systems, we manage to achieve the global optimum solution and our results are more energy efficient.