The choice of data processing location should be motivated by the following criteria: Energy, Cost, Amount of data, and Availability of data. The objective is to choose the most relevant solution for you by taking into consideration the issues of each of these criteria.
1- Energy optimization
Processing and sending data has strong impacts on energy consumption at all levels. In the case of IoT, the product is often powered by batteries or a limited energy source (solar panels…). The energy cost can therefore have a strong impact on the product design.
2- The cost of sending the data
a) At the level of the choice of the communication technology
Choice according to the amount of data
The amount of data to be sent via the communication medium is an important factor. A triptych exists and is composed of the quantity of data, a few bytes to tens of mega bytes and even more, the distance with the receiver, a few meters to several kilometers and the cost of the means of communication, level of electronic components and price of the data during its mobility.
In the IoT, there are 3 different ways to transport data :
- Wired link : RJ45, CAN, …
- Wireless over a short distance, less than 100 meters: Bluetooth, Zigbee, WiFi, …
- Wireless over long distance : LPWAN, GSM, Satellite, …
In the case of wireless networks, if the amount of data is small (from a dozen bytes for Sigfox to a few hundred or even a thousand bytes for LoraWan), an LPWA type network is sufficient. These types of networks have the particularity of consuming little energy and having a very low cost per data, less than 1 to 2 euros per year and per object.
If the amount of data becomes more important, the passage by operated networks (2/3/4G, NB-IoT, LTEM integrating a physical or dematerialized SIM card) becomes mandatory. This leads to higher costs for the electronic card (modem and battery to manage power calls) and more expensive subscriptions that are proportional to the amount of data sent, ranging from 2 to 10 euros per year and per object.
Choice according to the available energy
he energy to send this data is also to be taken into account, the International Energy Agency estimated in 2014, that 80% of the energy consumed by a communicating object is for its connectivity (source: https://www.iea.org/reports/more-data-less-energy).
The choice of the type of connectivity according to the main criteria
3- Quantity of data to process
In the case where the implemented communication link does not allow to send a large amount of data or it is not desirable to send a large amount of raw data (security and/or confidentiality of the data), the majority of the processing must be done locally: it is the Edge computing.
Storing the data locally and processing it involves additional costs in terms of electronics :
- Integration of non volatile memory (FLASH, SD-card…) for storage
- Resource for data processing: computing power (more powerful MCU) and volatile memory (RAM) to process this amount of data.
4- Data availability
The availability of data is a key element in accessing information to monitor the fleet. Some data must be available immediately (e.g. acceleration data for an ABS) while other data may be available without immediacy (e.g. location of a container carrier).
This availability is influenced by :
- Latency induced by data processing
- The latency of the communication link
- The reliability of the communication link (denial of service, white zone…)
- The location of the data storage
5- Security and confidentiality
The sensitivity and security of the data must be considered from the beginning of the project. A security audit must be planned throughout the design and also throughout the life of the product.
- Compliance with the RGPD data protection regulation
- The balance between the importance of the business data and the level of security to be implemented to protect it
- The willingness or not to be able to evolve this security over time (remote update)
The definition of the organization of the various actors for the role in the circulation, processing and service, are also a major element to be taken into account from the reflection on the creation of the product and the data flow. That is to say, the orchestration that must be put in place between the actors, so that the ownership of the data is never compromised.
ETSI has defined in a document, the rules to be respected and the uses to be implemented in order to satisfy the security of connected objects and the data collected, this document is the EN 303 645 V2.1.1 (2020-06) (CYBER; Cyber Security for Consumer Internet of Things: Baseline Requirements – v2.1.1)
6- Remote product fleet management
The management of the whole fleet allows to manage the maintenance of the products, to act in case of security problems on a product or a set of products.
A positive ecological impact is evident. It allows not to discard products that could evolve, in terms of functionalities and/or security, via remote updates. This management imposes to have a well dimensioned bidirectional communication link at the time of the design, i.e. to foresee the evolutivity of the product in a possible cost/evolution balance.