Gunnar Forsgren

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Kista, Stockholm, Sweden


Former Ericsson / Sony Ericsson development engineer.
30 years of engineering experience in telecom and mobile.
See LinkedIn: http://se.linkedin.com/in/gunnarforsgren

November 24, 2010

Mobimation Device Exchange - facilitating equipment communication over mobile 3G

Mobimation is developing Mobimation Device Exhange (MDE), a new proxy server software that hosts communication access to equipment that integrates Mobimation Enabler (ME), the Mobimation equipment access adapter.

The ME is a tiny micro controller module that can be integrated in all sorts of physical devices you come across in everyday life. The purpose is to allow human beings to be able to interact with that device from a mobile phone or web service in a way appropriate for that particular device.

Mobimation expects such ME´s to become a very popular way of breathing "intelligent life" into both existing equipment as well as for integration in new products in development.

"Intelligent life" here means giving equipment the ability to report status, allow configuration, interaction, remote as well as local access over a network. Lots of equipment exists that can today be operated and monitored only by direct physical attendance at the same place. "Dropping an ME" into the equipment can enable a whole new way of interacting at very low cost. More on this in the ME article.

To arrive at what the MDE does, this post first elaborates briefly on the subject of communication with equipment which uses mobile 3G networks for access.

Many cases of machine access involve a geographical location where mobile network access is required for cost effective deployment. The outside world may have a need to establish direct contact with the deployed equipment for further interaction.

Use of 3G mobile network mobile subscriptions and a corresponding 3G access router can be cost effective for rapidly bringing a system online without having to get involved with whatever fixed network access might be available at the location and the costs for getting connected that way.

One consideration is however important to look at.
Access in a mobile network occurs through APN´s which are essentially proxy servers that determines, as per mobile operator policies, how data access is allowed to occur. In case of some mobile operators these APN´s prevent external parties from initiating a network connection towards a party inside the mobile network. Same as if your friend runs a web server on a mobile phone and you find it difficult to be able to connect to it. End of story or what ?

No this can be worked out. A general way to work around this is to have the equipment itself initiate and maintain a connection to (analogous to "register itself on") an external server from where external parties can then establish further communication. Thus meaning the equipment is the initiating party and actively makes its service accessible on an external server.

You may compare this to how mobile phones users do things. There the user operates the phone in order to fetch web pages, send email, check out the latest Facebook posts, from within the mobile network.

The difference here is really that the initiatives of a phone user is represented by a programmed microcontroller with IO capabilities that determines what stuff to send and retrieve, representing functionality of the physical equipment it is part of.

The server external to the mobile network can either have as a role to put the equipment and a client in direct (synchronous) contact for direct command/response interaction (proxy server), or, can be any service that the equipment logs into and interacts with.

For example a simple dedicated service can be an "asynchronous remote data access location"
where the equipment dumps its data for later access by external parties in an on-demand way.
A variant is that the equipment simply logs in to an existing remote service on the Internet and interacts with whatever protocol is implemented.

In case of the proxy server, either the equipment assumes a role to stay connected relentlessly to this middleman server waiting for a request, or, is notified for example over SMS that its services is now requested and it should "come online". Such an on demand scheme can save power and resources on the equipment side for communication cases where a rapid initial response time is not required. In cases more than one client needs simultaneous direct access the equipment can spawn further connections with the proxy depending on its capabilities.

So what is Mobimation Device Exchange about ?
It implements a proxy server to which Mobimation Enabler (ME) adapters can connect and register availability. Clients that are interested in accessing a piece of equipment represented by an ME adapter go to the MDE server and looks it up. The client (for example a mobile phone application) can then establish a socket level communication with an ME where the subsequent traffic is relayed by the MDE proxy. This occurs in a two-step way. The client connects an announced access request port where the client authorizes itself. Upon granting access this service returns a reference to a service instance where that client can continue interaction with that ME. This way several clients can establish simultaneous sessions with the same ME unit. Several such sessions can be ongoing simultaneously between potentially thousands of clients and lots of ME adapters via the MDE server. The MDE thus becomes a central Internet access hub for communication between clients and ME equipped products. Mobimation Device Exchange is not limited for use in mobile network commectivity but for the sake of an uniform hub solution is applicable to use also with ME adapters that connect using a fixed (cable) network connection.

MDE can also be used by equipment that integrate ME as a hub to establish communication between ME´s (Machine to Machine) regardless of location.

MDE also manages support for paid access to select features in equipment such as vending machines, car wash stations or similar service facilities. Its placement in a fixed network environment have it meet sufficient security requirements for handling the exchange of payment tokens with payment services and access authorization for the particular ME adapter using a secure protocol.

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