# Wireless Communication Technologies for Smart Grid Distribution Networks +
## 4 Previous Studies on Selecting Suitable Technologies for Power Line Monitoring
### Comparison of Technologies  
Wireless sensor networks are built from nodes that must be low cost and have very low power consumption. At least one of these two requirements is met by the available technologies presented in this summary, such as IEEE 802.15.1 (Bluetooth) and IEEE 802.15.4 (ZigBee). There will be cases where one technology will be preferred over the other, depending on the application type, environment, sensor node technology, and network configuration requirements. Therefore, there is a clear need to analyze different technologies with respect to each other in order to be able to decide which one would be more suitable for a given application, with certain constraints and requirements. [PERSON] et al. [21; 22] numerically addressed the issue of the lifetime of a WSN to compare Bluetooth and ZigBee in a particular application. This was the first study to compare such technologies in the context of WSNs. The authors used the EMORANS scenario as a framework for the comparison. EMORANS defines the test conditions for wireless communications, as follows:  
* The geometry of a square layout of a side is set to \(100\) m.
* A node density of either \(100\) or \(500\) nodes is used with a uniform distribution over the square. * A sink is required for periodically collecting the measurements performed over the sensed area by nodes. * The initial battery charge is set to \(1\) Joule to facilitate shorter simulations. The channel model loss in logarithmic scale should be \(k_{0}+k_{1}ln(d)+s\), where \(d\) is the distance, \(k_{0}=40\) dB, \(k_{1}=13.03\) (obtained through experimental measurements made in the field in a rural environment), and s is a Gaussian random variable, with a mean of zero and a standard deviation of \(\sigma\), modeling channel fluctuations. The capture packet model used states that a packet is correctly received in case the loss is smaller than a given threshold, Lm, which depends on the technology used. * The three definitions of network lifetime are as follows, where a round is the time elapsed between two consecutive measurements:
* The interval of time (measured in rounds) from the first transmission in the wireless network to the point when the percentage of nodes with remaining energy drops to zero. * The average percentage of nodes that remain reachable within the network over a specified time window. * The average percentage of reports sent from nodes to the sink over a defined time window. If in any of these definitions, the lifetime falls below a specific threshold, which is set according to the type of application, the quality of the lifetime is considered low. The first definition takes into account only energy consumption issues, whereas the second takes into account both energy consumption and connectivity issues. The third definition refers to energy consumption, connectivity, and MAC failures. In Figure 2, a comparison of Bluetooth and IEEE802.15.4 is provided, considering two networks composed of 500 and 100 nodes. Figure 2 shows the rounds at which the number of reports arriving at the sink from the nodes started to fall below a certain percentage (a threshold), indicated on the x-axis. ZigBee exhibited a longer lifetime compared to Bluetooth, supporting up to 80 nodes. However, beyond 80 nodes, the lifetime of ZigBee is not shown because in the first round, more than 10% of packets in the 100-node case were lost. The choice of technology depends on the application requirements. If, in fact, one considers a network composed of 100 nodes and an application that requires that the sink receives 100% or 90% of the packets, one would choose Bluetooth because IEEE802.15.4 cannot attain these percentages. In the case where the application can tolerate a loss of more than 10% of the packets, IEEE802.15.4 is better because it establishes a more energy-efficient network. [PERSON] and [PERSON] (2018) presented a comparison of the major characteristics of the two main protocols for short-range terrestrial communications: WiFi and Bluetooth.