The importance of testing M2M devices

Normally any communicating M2M device starts with a modem/module from manufacturers like Cinterion, Sierra Wireless, Telit or Ericsson. These modems have all been type approved according to tests specified by 2G (GSM) or 3G (UMTS) standards, just like any mobile phone in the market.

So far so good, but in the case of M2M these modems are then built into products (e.g electricity meters, vehicles, credit card terminals etc), so additional hardware and software is added to make a complete product. On top of that some sort of central system or service application is normally needed to retrieve, handle and store data from the products.

Because of the additional complexity in a M2M applications potential problems can occur.  Below are a few examples:

- The modem is type approved, but not the complete product including system software with complete functionality – problems are discovered too late after commercial launch begins
- We did some field testing with 10-20 units and everything worked fine, but when our solution grew to thousands of units we did not understand what was needed for them to  co-exist and behave in a controlled manner in the mobile networks

In order to avoid unpredicted cost (re-visits of already deployed products or re-calling of products) it is imperative to test and validate key traffic and signaling behaviour in a test lab environment where different mobile networks can be simulated in a controlled manner, thereby allowing test situations that are hard or impossible to simulate in real life.

Customer products can be tested to dig deeper and determine things like:

• At what received signal strength does the product loose connection to the network?
• If connection to the mobile data network (GPRS) is temporarily lost, does the product re-connect as it should?
• Do handovers between cell sites or networks work correctly without lost service or data?
• How much data is used for a unique transaction, how much data is consumed for overhead signaling in a specific scenario?
• Does the connected unit handle network error codes in a correct manner?

These are just some examples of things not so easy (or even impossible) to test when connected to a live network. Tests like these have proven to be successful when developing and securing end to end communication functionality as well as and choice of aerial/antenna for optimized and cost-effective installation and operation.

Telenor Connexion encourages all our partners and customers to spend a couple of days performing tests like these in our test environment. After all, a couple of days of testing is a small effort compared to a scenario of having to re-call a multitude of deployed products.

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