Each Smart city needs a structured & tailored computing model to allow distributed processing of data with high level of scale, speed, resiliency and mobility required to efficiently & effectively deliver the value with the data being generated.
In smart city IoT infrastructure we see four-layered architecture
Street Layer: It comprises of devices and sensors that collect data and act. Here is a representative list:
- A magnetic sensor can detect a parking event by analyzing the changes in the surrounding magnetic field whenever a heavy metal object or car comes close
- Lighting controller to dim or bright lights based on the timer or ambient conditions
- Video camera along with video analytics can detect vehicle, faces and traffic conditions
Air quality sensors
- Device counter to give an estimation of a number of devices, rough idea of the number of vehicles or pedestrians.
One key aspect is to choose edge analytics so that there are minimal delays in receiving right data. Also, as communication channels many options are there – majorly cellular technology but LoRaWan is also growing.
City Layer: This is above street layer with router & switches. It aggregates all data collected by sensors. This layer needs to build around resiliency to ensure packet coming from sensors or gateway will always be successfully transferred to head-end station.
Data Centre Layer: Ultimately all collected data needs to be sent to the data center for processing and extracting meaningful data. Cloud model is the chief means of delivering storage, virtualization, adaptability and the analytics know-how that city governments require.
Service layer: The collected data should be visualized according to the specific needs of all consumer e.g. parking data, traffic information and congested roads, estimated travel time for public transport, waste management route, connected ambulance, street lighting, pollution level and smart grid.
Smart city security architecture
A serious concern of most smart cities and their citizens is data security. Sensors should have their own security protocol, data encryption, sensor authentication, authorization through pre-installed X.509 certificate and public key infrastructure (PKI). City layer which also acts as a network layer should have Firewall, VLAN & encryption. Integrating with the latest technology framework such as mTLS or OAuth 2.0 for device attestation and identity-based access a city solution will be able to ensure the overall integrity.
Reference: CISCO Press