# Wireless Communication Technologies for Smart Grid Distribution Networks +
## 3 Requirements of Sensor Networks Implemented in the Power Line  
The basic unit performing measurement tasks at a specific point on a distribution line was previously defined as a sensor node. The concept of the Sensor Network (SN) refers to the gathering of sensor nodes located in different sections of a power line through an appropriate communication link. This concept arises from the necessity of coordinating a large number of sensors for real-time monitoring in different parts of the power grid. It is motivated by the availability of modern low-cost sensing and communication technologies. Among the challenges that the implementation of reliable SNs presents are the harsh, uncertain, and dynamic operating environments, as well as energy concerns. There are three main technologies that currently need development within the topic of SNs: sensing, networking, and information processing. The challenges, difficulties, and available technologies are discussed by [PERSON] et al. [10; 11], from which the following main requirements can be highlighted:  
* The need for simple network protocols and algorithms for sensor nodes with limited computational and memory capacities. * The self-healing capacity of the networking strategy, as sensor nodes are prone to failure in hostile environments. Wireless communications offer the most flexible and straightforward interconnection between nodes. However, their use in power system environments presents security and reliability concerns, such as EMI, fading signals, bandwidth overloading, and security. Despite this, wireless networks are still considered the most attractive technology for this development. These technologies are known as wireless sensor networks (WSNs). The Institute of Electrical and Electronics Engineers (IEEE) has produced several standards related to communication in power systems. Notable standards include IEEE 802.16 (WiMAX), IEEE 802.11 (WiFi), and IEEE 802.15 (wireless personal area networks). These standards may not be specific to power systems but are often used in various applications, including power systems [12]. In [13; 14], the authors recognized the four major challenges of WSNs in smart grid applications:  
* Harsh environmental conditions: The connectivity of networks can vary due to link failures, and sensors are susceptible to RF interference. * Reliability and latency: Due to the time sensitivity of sensors, the controller has to receive information in a timely manner. * Link capacity: The bandwidth of each wireless link depends on the interference level at the receiver, leading to high bit-error rates (BER) ranging from \(1\times 10^{-2}\) to \(1\times 10^{-6}\). The latency at each link varies continuously, so it is hard to meet QoS requirements. * Design and implementation resources: Energy, memory, and processing resources are limited, so the protocols for WSNs are tailored to ensure high energy efficiency. Finally, among the most important capabilities that any communication technology developed for a smart grid application should provide are the following:  
* Security, as initial experiences in smart meter installations in households have already shown that public concerns about new smart grid technologies should not be ignored. * Reliability, robustness, and availability, which are provided by most wired technologies. However, hybrid solutions using wireless and wired technologies might be used for the whole infrastructure. For wireless solutions in NANs, wide coverage is needed. Therefore, reliability is important, with latency low enough not only to satisfy demand-side management (DSM) requirements but also to serve all other AMI applications. This translates to a minimum reliability of 99.5% and a latency requirement of less than 1 s, which is a relatively relaxed figure compared to commercial broadband requirements [15]. HANs require a minimum reliability of 99.5% and a latency of less than 5 s, as they are shorter in reach and easier to access within the AMI.