When you’re deciding which Smart Cities IoT device to use, there are lots of important decisions to make —most importantly the mode of connectivity. Wi-Fi and cellular are two long-standing and popular IoT network protocols, more recently joined by LoRa (Long-Range, Low-Power) wireless networks, and of course there are advantages and disadvantages of each depending on the application.
For example, if a device requires constant, reliable service in a controlled, indoor, close-range environment, then Wi-Fi is the obvious choice. If a device is mission-critical, Wi-Fi connectivity isn’t going to be an option so cellular internet is the best wireless choice. But, if there is a large number of devices that are not mission-critical and operate in places indoors or outdoors where a signal often won’t reach, then LoRa is the best option.
One of the most important things to remember is that Smart Cities IoT applications do not typically produce a great deal of data, and that data is rarely mission-critical.
This article takes a closer look at the IoT device application communication mode debate and weighs the pros and cons of each.
Using cellular network connectivity
Devices that uses cellular internet connectivity connect directly to the wider Internet. Each device requires a paid SIM card and requires a dedicated electrical connection or has very limited battery life. Cellular communication is relatively expensive, but is ideal for situations when the data must reliably reach its destination.
Application suitability for cellular sensor networks
- Better privacy protection
- Public Wi-Fi can be insecure and data may not be encrypted. Private Wi-Fi is more likely to be secure. Cellular data is always encrypted, and therefore remains private. LoRa data is also encrypted and there is too little bandwidth for it to carry any voice, video or otherwise recognizable data.
- Wireless range
- While Wi-Fi’s capacity is limited to the range of the router and presence of physical obstructions, cellular internet connectivity has no set range and good building penetration. 4G building penetration is good, however 5G penetration is notoriously very poor. Devices can connect over cellular from anywhere there’s a viable cellular signal. LoRa is limited to the effective range of the gateway antenna, but signal penetration is excellent.
- No access to a router required
- Wi-Fi devices are tethered to the range of the access point or router and LoRa devices are tethered to the range of the gateway antenna (up to 5km in urban and 25km in rural areas). Cellular connectivity just need a viable cellular signal.
Cellular sensor pros and cons
PROS
- Ideal when an application must have a reliable network
- Data always encrypted
- Ubiquitous wireless range in urban areas
- 4G has reasonable signal penetration
CONS
- Expensive for a large number of devices
- Devices must be within range of cell service
- Devices must have dedicated power or very large battery
Using Wi-Fi network connectivity
Devices connect to the Internet through a wireless access point (WAP), usually located within the close proximity to the device, operating best in an open, indoor environment. Wi-Fi networks are typically designed specifically for an application and consist of multiple WAPs. Devices must be registered to the WAP and the network must be regularly managed and maintained for access security.
Application suitability for Wi-Fi sensor networks
- Secure, fast access to connect multiple devices in your private home
- While public Wi-Fi hotspots have a reputation for being unsecured, private Wi-Fi can be encrypted and thoroughly secure. To connect multiple devices in or very close to a private home, office or place of business such as a restaurant, Wi-Fi is the best and most affordable solution.
- Video and large data file streaming
- For IoT devices such as video security systems that need to transfer a high volume of data in real-time, Wi-Fi is currently the best option (although the emergence of 5G might change that in the near future).
Wi-Fi sensor pros and cons
PROS
- Unlimited data transfers,
- Secured in private settings,
- Good for video and other data-heavy IoT devices
CONS
- Requires a wireless access point or Wi-Fi router
- Limited range
- Security risks for devices using public hotspots
- Poor signal penetration
Using LoRa network connectivity
Devices connect to a gateway antenna within proximity of the sensor. The data is relayed from the gateway to the database via cellular or Ethernet backhaul.
Application suitability for LoRa sensor networks
- Secure, best-effort connections for large numbers of devices for multiple applications
- Large deployments of sensors for applications in smart buildings, geographically dispersed sensors in a fixed radius, or environmental applications should use LoRa.
- Battery life
- LoRa sensors can operate on solar power or on a button battery for several years which reduces maintenance costs and allows for long-term collection and analysis of ambient data.
LoRa sensor pros and cons
PROS
- Extremely low power consumption
- Secure encrypted data
- Excellent signal penetration
- Simple sensor installation
- Capable of two-way communications
- Only one gateway is needed to operate thousands of sensors
CONS
- Limited to low-bandwidth applications
- Range limited to gateway antenna radius which is dependent on geographical topology
- Best effort data collection