So far we’ve talked about the telecommunications responsibility – how telecommunication can empower a smart city and its residents. In this section, we highlight how connectivity acts as an enabler of smart cities.
Connect all devices with a citywide, multi-service communications system(s). This universal target deserves additional discussion as it applies to telecommunications.
Earlier we discussed the importance of high-speed access and citywide wireless. For connectivity purposes – for connecting sensors, switches and devices – it is not strictly necessary to have either one. In theory, connectivity can be accomplished with low-speed wireline technology. Many electric power utilities, for instance, use low-speed powerline technology to talk to their smart meters and sensors.
Regardless of the telecommunications technology you choose for device connectivity, strive to make it a “multi-service” network. That is, try to use it for a variety of purposes across different city departments. If each department stands up its own special-purpose network, your city will spend far more than needed. What’s more, it will have a harder time
managing and maintaining all those disparate networks. And a harder time passing data back and forth between departments. In fact, the services architecture layer should be abstracted from the underlying access network technologies. This enables the network to be continually upgraded with less disruption of the service layer
The clear trend worldwide is to move away from slow, single-purpose communications to fast, multi-service networks. This implies that you may be able to achieve device connectivity by using a high-capacity network that is already in place – be it cellular/mobile 3G or 4G-LTE, WiFi or other solutions like RF mesh, though data rates vary dramatically. You should identify which technology makes the most sense for your city according to your performance and cost requirements, and your circumstances.
If you are approaching device connectivity for the first time, then your technical team must take a hard look at two aspects: bandwidth and latency. Bandwidth is the amount of data that can flow through at one time (just as the width of a pipe determines how much water can flow through). Latency is the time lag to get data back and forth. A network can be high bandwidth (lots of data at the same time) but also high latency (a slow roundtrip). Or vice versa.
Your technical team must carefully determine your bandwidth and latency requirements. For instance, a network for monitoring street lights
may be able to get by with high latency (a slow roundtrip). After all, it doesn’t really matter if a light turns on or off a few seconds late. But a network for monitoring electric power substations may need very low latency (a fast roundtrip). That network must be able to send and receive signals very rapidly so it can prevent a small outage from cascading to a big blackout.
Whatever your current requirements, try to leave headroom for future growth. At the very least, make sure that the products you choose are “future-friendly” – are capable of expansion when the time comes. In the early days of the smart grid, for instance, some pioneering utilities selected underpowered connectivity solutions in the hopes of saving money. But they spent more money in the long run. Many of them had to go back and upgrade their initial network a few years later. Others had to put in a new system parallel to the old one to get enough capacity. If you build it, they will come, so build in as much extra capacity as your budget allows.