To ensure the success of your IoT solution, careful consideration must be given to the data consumption for each endpoint. Elements such as battery life of the device, the capacity of CPU, the costs of transferring and storing the data must be carefully analysed.
The article aims to highlight the primary decision criteria for the allocation of the right data volume for each device involved in connectivity. Depending on your industry or business sector, the following factors affect the data consumption and transfer:
Type of device – Smart meters, Industrial equipment, Sensors, etc.
Sample rate – frequency of samples per second
Resolution – the data size in each sample
Signal conditioning – defines the (ir)regularity of initiation the data transmission based on different factors (time of the day, season, etc.)
Amount of local data storage – the size of the hard drive, keeping the processes, etc.
Power consumption requirements of the device - the battery life, accessibility of the device, etc.
For example, consider a smart sensor responsible for notifying the quality elements of water tanks in the rural areas with the deficit of drinking water:
Device – Water sensor that measures Temperature, pH, etc.
Sample rate – 10 kHz (2x of range 0 – 5 Hz)
Resolution – 16 bit (2 bytes)
The signal conditioning – each one hour
Amount of data: 20 kHz x 2 bytes = 40 kb/sec
The # of sensors 1000
Amount of data: (40 kB/sec x 1000 sensors) x 1 = 40 MB/hour
A rough calculation shows that each sensor must have in readiness at least 28,8 MB data volume. In addition to this amount, we must also consider a different type of additional small data requests initiated both by endpoint and the central system. The final approximate data volume for each device can be 30 MB.
Sometimes, especially at the early adoption stage of business, the usage pattern of the devices generating the data might not be equally distributed, and instead be followed with the different fluctuations. In this case, it would be expedient to start with the Pay as You Go pricing plan and monitor the data generation and transfer regularity.