Why M2M devices don’t roam

Posted on by William Webb

Using cellphones has made us very familiar with the concept of home networks and roaming. The home network is the one owned by the operator with who we have a subscription. If we join a different network we are considered to be roaming and often pay a much higher tariff for the privilege. But such a concept need not and indeed should not apply to machine communications.

Take the example of a Japanese car manufacturer such as Honda. They might embed Weightless M2M chips within the engine management system of cars that they are building. These cars will leave Japan and be delivered all around the world. Even once delivered they may move from country to country, both when owners travel and when the car is sold on. Ideally they should locate a Weightless network wherever they happen to be and communicate seamlessly. The concept of a home network and roaming makes little sense in this case. The difference occurs because the billing relationship is with Honda which is a multi-national company and not with an individual spending most of their time in one country.

Of course there will be national networks and Honda will need to pay these for the traffic carried. Weightless has the concept of a service provider who has an agreement with multiple operators around the world and offers Honda and others a service across all these networks. The service provider becomes the “home” for the device. The Weightless devices – cars in this case – always connect to this service provider through partner national networks. In this case there is no roaming, just the network the device happens to be connected to. There are certain implications of this arrangement – for example security keys cannot be stored in the “home network” because there is no such thing. Instead they are stored at the service provider level in a secure manner that allows companies to change service providers should they wish.

This is yet another example of how a network designed for people is inappropriate for machines. This has been recognised to some degree by cellular operators, some of whom are working with Jasper Wireless to try to establish an approach that enables machine roaming. But, as we have observed, machines do not roam and so this approach will always be second best to a custom-designed network.

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5 Responses to Why M2M devices don’t roam

  1. A significant complexity in the GPRS and 3G standards applied to M2M is in the basestation registration. In a weightless world, there will be some machines which will never move and others which will be highly mobile, the Honda engine monitoring for example. How does weightless handle these two very different applications?

  2. avatar William Webb says:

    Weightless has been designed with this in mind from the start. It optionally tags stationary devices (either by being told they are stationary or deducing that they never move) and then deals with stationary and moving devices differently. For stationary devices it uses location knowledge to schedule commuications to them optimally taking into account local interference and so on. Moving devices have a different regime where they “hand themselves over” as in WiFi – ie they log onto a new cell when they believe it necessary. There are parameters to prevent excessive log-ons for fast moving terminals.
    I think we’ve done a pretty good job at exploiting both the fact that some machines don’t move and others don’t need seamless handover to both simplify things and reduce signalling traffic massively.
    Do feel free to ask more!
    William (CEO of the Weightless SIG)

  3. avatar Dawood says:

    any update regarding the news, that Honda might embed Weightless M2M chips within the engine management system of cars that they are building or any other automove application of Weigtless.

    • William Webb William Webb says:

      Unfortunately we cannot comment on any developments that the companies themselves have not chosen to yet make public. We anticipate announcements over then next few months and when they are made then we (Weightless SIG) will publicise them but until they are disclosed our hands are tied! Sorry.

      Reply by Weightless Marketing

  4. avatar Dawood says:

    Have any of your research team consider the role of TV white space access in future networks(such as deployment of telecom services in cloud).

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