# Design, Deployment and Evolution of Heterogeneous Smart Public Lighting Systems
## 5 Network Architectures and Transmission Technologies
### Communication Technologies for Smart Lighting Infrastructures: Conclusions  
At the end of this section, some conclusion can be drawn concerning the choice of the communication technology best suited to public lighting scenarios.  
**Wired or wireless networks?** The first question that must be addressed is whether to rely on wired or wireless solutions. In the authors' opinion, wired networks, although currently adopted in many street lighting infrastructures, do not represent a reasonable choice when considered in the modern perspective of smart city and IoT scenarios. Such kind of networks, mainly implemented using PLC technologies, represent dedicated communication infrastructures, aimed at providing only the smart lighting service. Considering the ongoing evolution of urban environments, which will be more and more studded with smart object requiring connectivity to exchange data, the deployment of a city-wide network to support a single service is certainly, if nothing else, a missed opportunity. Contrarily, wireless networks are the key enablers for upcoming smart city and IoT applications. Their flexibility, widespread coverage and low deployment cost make them the only feasible choice to interconnect the multitude of smart devices that are being deployed in our cities.  
**Street lights as smart objects or connectivity providers?** Each streetlight of a smart lighting infrastructure might be, on the one hand, one of the many smart objects (sensors, meters,...) disseminated in the urban area, which require a wireless connection to operate, or, on the other hand, it could be itself part of a city-wide wireless network that provides connectivity to other objects.  
Undoubtedly, the former is the simplest solution. Under the coverage of a third-party wireless network (e.g., cellular or Sigfox), connecting a streetlight to the smart lighting infrastructure simply means to provide it with the proper radio interface and turn it on. It will immediately connect with the wireless network that is already in place. The main downsides of this choice are the need for a service subscription that covers all streetlights, with the corresponding fee to be paid to the network provider, and the impossibility to gain revenues from the smart lighting infrastructure, which remains a passive asset.  
On the other hand, turning the smart lighting infrastructure into a capillary, multifunctional, city-wide communications network, capable of relaying information, gathering data and delivering services to and from IoT devices, makes it a dynamic platform serving as backbone for smart city developments. In this case, the public light asset offers opportunities to deliver new services and  
Figure 4: Bluetooth/IEEE802.15.4 mesh-based smart lighting architecture.  
generate revenues, instead of just being a cost factor. However, this requires the installation of a private network (e.g., LoRa or mesh).  
The latter scenario is certainly the most challenging one, as it requires a higher commitment by the lighting infrastructure holders. They need to be fully involved in development path of the urban area in which they operate, as they play a key role in the process that turns a city into a smart city.  
To conclude this discussion, Table 1 provides a SWOT analysis (strengths, weakness, opportunities, threats) of the previously introduced communication technologies for smart lighting applications. Focusing the attention on wireless communication technologies, in the following section we will provide the design criteria of a smart lighting infrastructure.