Service aspects of M2M communications

As M2M switches to GPRS, selecting the right service is the key says Mike Collen of Acte Components.

As M2M switches to GPRS, selecting the right service is the key says Mike Collen of Acte Components.

One of the most appealing ways of adding wireless connectivity to a machine, device or sensor is to use the public cellular networks.

The approach has many advantages, not least that cellular coverage is now more or less ubiquitous, allowing the mobile device to work anywhere.

Moreover, the networks are inherently interconnected with the wider communications infrastructure: this gives equal freedom of location for the central site (or peer machines) as for the mobile device.

Cellular networks are built for carrier class reliability and provide low cost-per-bit.

On a practical level, such implementations are also easily devised and realised.

Vendors such as Siemens provide ready type-approved GSM/GPRS modules that can be integrated into any appliance, often via a high level interface.

Not only does this ease the designer's task, it averts the possibility of system changes that could require costly and time consuming re-approval.

Most modules now also include multiband facilities, to allow roaming and the selection of least-cost network options, and to provide a hardware platform that can be used with products deployed anywhere in the world.

GPRS M2M services are now taking over from SMS-based systems, as designers realise the advantages of moving to IP-based infrastructures.

Not only do such always-on systems produce further reductions in cost-perbit, they also allow the use of established networking techniques - for instance in security, verification and encryption - that have been proven in use on the Internet and worldwide web.

Device manufacturers, however, have often struggled to make practical use of the long list of benefits of cellular, and GPRS in particular, largely because the overall communications function is not just about the device.

Many facilities need to be overlaid on the base network in a technically complicated process that requires a great deal of software development.

In particular, the network needs to be secure and resistant to malware and spam: not least because unwanted incoming communications cost money in a pay-per-bit environment.

Just like any other form of communication, M2M also requires an appropriate billing system, and a billing structure that makes economic sense for the network operator, service provider, device manufacturer and end customer.

Sometimes the system also needs to interface with the PSTN, and perhaps most importantly of all, must work smoothly with the end customer's existing IT infrastructure.

This means that the device manufacturer needs to partner with both a subsystem manufacturer that can provide the right hardware modules and embedded software support and with a service provider which understands M2M requirements.

Alternatively it may be possible to find a "ready made" partnership that can offer a virtually turnkey communications solution.

At Acte Components, for instance, we have recognised this need and partnered with service provider Wireless Logic.

This provides the customer with a solution at the device level, and a complete layer of functionality sitting on top of the cellular network.

Wireless Logic effectively offers airtime services via its ManageNet product.

The device developer receives ready-activated SIMs that are added to the device at the point of assembly, reducing overall costs.

The SIM includes a static IP address for better security and reliability, and ease of development and configuration.

To protect against network outages, ManageNet has its own private kilostreams operating across the mobile networks' GPRS gateway support nodes (GGSNs).

If one network goes down, the other will automatically step in.

Wireless Logic also maintains VPN tunnels and private leased lines allowing a secure private service to be up and running within 48 hours of its activation.

Authentication, private communication via VPN and leased line, and triple DES III encryption all act together to keep customer data secure.

ManageNet also has its own data centre which enables core communication without the use of public networks, and allows the establishment of a route per SIM or per customer as soon as the GPRS connection is established to the application server.

Billing is one of the most important benefits of using a one-stop M2M service.

Without facilities such as direct billing to the end customer, revenue sharing, and advanced, flexible tariff definition, it can be difficult to devise a profitable business model for all concerned.

The billing system must also be scaleable, since M2M often involves networks with tens of thousands of nodes.

Branded airtime contracts, credit checking, provisioning and bill collection (via invoice or direct debit) are all elements that must be considered.

From a hardware point of view, developers need to check that the modules they choose are type approved.

Siemens modules supplied by Acte, for instance, meet all of the requirements laid down by the R and TTE, FCC, IC, UL, GCF and PTCRB.

Attaining type, board and operator approval is a time-consuming, costly and unpredictable business, so any changes to the communications module are to be avoided.

GPRS offers the best option yet for M2M communications via an IP-based backbone: a fact that developers have clearly discovered if we are to judge from the rapidly expanding number of high-volume implementations using the technology.

With 40 billion potential candidates for networking, it's a market that looks set to be around for some time to come.

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