Your M2M application needs long-range communications capability ...
... the data your device gathers needs to be sent to a system or person or other machine ...
... you need to reach out and control and manage a device from far away ...
Thus, you are ready to proceed with selecting the network and services for this long-range communication requirement.
The overwhelmingly logical choice for a wide-area network (WAN) for M2M applicationsparticularly if the device is truly physically mobileis Cellular Wireless Data services (from Aeris, of course!)
Now, you need to pick a cellular radio and select a wireless data service!
And the Questions Arise
But the available cellular technology choices are quite confusing! Naturally, many questions crop up:
- Which cellular technology should I select?
- What are the 2G and 3G data speeds?
- All the carriers are talking 4G nowshould I start using 4G?
- If I pick a 2G or 3G technology, what is its longevity?
- And so on ...
Unfortunately, there aren't any simple and easy answers! My initial response to the question Which G is Right for M2M? is simply:
This may seem like a non-answer, but it actually isn't!
Indeed, the choice does truly depend on a number of factors. The rest of this postand other ones to followdiscusses these factors and is intended to help you to make the best decision on the cellular technology to use for an M2M application deployment.
Let's start with discussions and information to set the context.
M2M Devices Are Different
What Do Handsets Have?
The cellular handset is simplerelatively speaking, of course!compared to M2M devices. Most handsets fall into a few general categories, and the majority of handsets are either basic cellular phones (for making voice calls and sending text messages) or smart phones (for sending and receiving datae-mail and web surfingin addition to voice calls and text messages).
Smart phones are often used as devices for accessing the Interneteither to web sites using a browser, or via laptop and notebook applications that use the handset as a tethered connectivity device.
Most handsets have much in common:
While some handsets have keyboards, others make do with special multiple-key-press character entry (for example, to enter text for SMS messages).
- Keypads for dialing phone numbers.
- LCD screens for basic phone and smart phone use.
- Rechargeable batteries.
- Very similar physical dimensions (well ... there are some exceptions, of course!).
- Simple QWERTY keyboards (for more than just number entry).
M2M Devices are Unique
M2M devices, on the other hand, are usually very unique. With the exception of a few self-contained cellular modem products (for example, from MultiTech Systems), every M2M device is designed from scratch for a specific purpose.
An M2M device generally contains (as needed ... depending on the specific application):
- A cellular radio unit, called a Module, from Telit, Sierra Wireless and others.
- A processor that runs the program (firmware) for the M2M application.
- Volatile and non-volatile memory for the firmware and data gathering storage.
- Sensors for the specific data gathering functionality.
- Analog-to-Digital and Digital-to-Analog converters.
- Global Positioning System (GPS) chips for determining location.
- Power conditioner circuits (for example, for electrically noisy vehicle environments).
- Battery, if required.
- Cellular and GPS antenna and power connectors.
The look and feel of the M2M devices are often quite differentsome are as small as a handset, others may be comparable to a tiny notebook and yet others are larger than a bulky laptop case.
Often, devices installed in physically mobile applications may require special construction for vibration and environmental issues. Boards and components may be encased in sealing material to avoid shock and vibration effects. Temperature ranges for normal operation may need to be wider than standard handsets, etc.
M2M Applications Are Different
Traditional Handset Applications
Let's review the traditional wireless data applications for which Carriers provide service:
- Handsets for text messaging, e-mail, surfing the web and a few business applications.
- Laptops and notebooks with wireless data cards for the same purpose.
Of course, I am not considering other applications (games, tools, etc.) on Android and iPhone handsets that are not related to wireless data messaging per se.
Varied M2M Applications
These are just a few examples of M2M applications that differ from handset uses:
- Tracking trucks on highways for location and dispatch reasons.
- Logging driver logs into central locations.
- Checking cargo loads in trailers and reporting when they are loaded and ready for pickup.
- Reporting automobile theft and tracking them when stolen.
- Sending an Automatic Crash Notification (ACN) when an air-bag deploys.
- Sending fire and burgler alarms for residences and businesses to monitoring stations.
- Transmitting blood pressure readings to a Doctor's office.
- Reading an electric or gas or water meter remotely.
- Reporting a jammed irrigation system to send out repair technicians.
- Reporting failed heating and air-conditioning equipment in commercial buildings.
Usually, the data is sent from machines (M2M devices) to other machines (host systems, databases, etc.) without human intervention.
In these various M2M applications, the firmware in the device is very differentthe program code, frequency of data transmissions, quantity of data sent each session, alarm conditions, information encoding methods, retry algorithms on failures, etc. are usually not the same from device to device.
Network Coverage Needs Are Not The Same
Users Don't Actually Roam Much
Carriers have enabled their users to roam freely and make voice and data calls throughout their coverage areas, as well as in other carrier markets through roaming agreements. This makes it possible for business users and travelers to receive cellular service even when away from their home market.
Yet, most handset users do not actually roam outside their home marketor certainly not often enough for the roaming capability to be heavily used. For the vast majority of handset users, their phone registers in one market and stays registered in that market for long periodsdays to weeks to months (perhaps never leaving it!).
People with long commutes may traverse through only one one or two service boundaries (switching centers) a couple of times a day, when driving to and from work.
This is what allows smaller Carriers in the US to be remarkably successful, with deployments that cover markets sufficiently well for their customers to receive good coverage and good service.
But M2M Devices May Move a Lot
Unlike handset users, certain M2M devices may move from market to market quite often!
For example, a long-haul truck may drive through many markets in a single day ... operating on many switches, and, often, on more than one or two Carriers. The trucks may need to send and receive data in areas where smaller Carriers may not provide coverage, or where a small Carrier may not have a roaming agreement.
If the cellular technology used in that M2M device in that truck is not available in a particular market or region, then that truck is not able to send or receive data when in that area. It may need to buffer the data and wait till it is in coverage to send the information.
If the time that the truck is outside coverage is long, then the purpose and timeliness of the M2M application may be lost.
Coverage Matters for Distribution & Operation
Handsets are Only Sold in Covered Markets
In handset sales, where the service is usually sold to an individual user, it is generally possible to make a clear determination whether the user is in the Carrier's service area or not. Carriers open their stores and establish sales in their own coverage areastheir sales agents can determine whether a particular customer can clearly use their products and services. Their web sites query for the zip code of the potential customera relatively easy indicator of whether the sale is viable.
For example, it is possible that the customer may be in an area that is not yet covered with 4G service, and the sales agents will steer them to purchase a 3G handset ... for now!
M2M Distribution/Operation is Often Nation-wide
For M2M, the company selling the device and the application to their customers must ensure that it works where that the end-user customer expects it to operate.
For example, an application within a major citysuch as a towing company dispatch systemcan use 4G cellular technology if it is available (and desirable). But a long-haul trucking company simply cannot use 4G service today, since it is not available in the majority of the markets in which their trucks are deployed.
Furthermore, if a particular M2M application is sold nationally, the device must be shippable to all locations with an expectation that it will work after installationeven if it is a Fixed Application (i.e., one that is not physically mobile).
Handsets Are Turned Over Frequently
Not too surprisingly, the cellular industry has created an expectation that customers will replace their cellular handsets frequently.
This rapid turn-over fuels the rapid development of new technologies and new handsets. Handset manufacturers are always adding new features and capabilities that make their users splurge on the next new handset that is introducedthis phenomenon is not just limited to iPhone users, by the way!
Carriers and customers sign service contracts (for example, when subsidizing the cost of the handset) for two years typicallyat that point, most Carriers offer significant incentives to make the customers get a new handset and renew their contract.
Thus, if a Carrier wants to discontinue a technology and service, it is possible for them to transition their handset users in a relatively short periodcustomers can buy new devices at the stores or get shipped new units and begin using them immediately. Generally within one or two cycles of contracted service, most customers can transition to the new technologyany remaining customers can be offered further incentives to switch.
When CDMA cellular technology was first deployed, handsets were Dual-Mode: they operated in digital CDMA mode in markets where digital CDMA service was available, and in analog AMPS mode where CDMA was not available!
As the CDMA digital coverage improved, Carriers began selling CDMA-Only handsets and refusing to establish new AMPS service for old AMPS-Only handsets when they were brought inyears before the FCC-mandated AMPS Turndown date of February 18, 2008.
This allowed them to easily minimize the impact of the AMPS Turndown for their traditional handset customers!
But M2M Devices are Deployed for Years
M2M devices remain operational for yearsfar longer than traditional handsets. This is due to a number of reasons, of course ... some of which are:
- The devices are often not user-replaceablethey cannot be carried in to a store and changed out.
- They may be embedded inside other machineryrequiring a service call where a trained technician replaces the unit.
- The device cost is not subsidized by Carriersdevices must remain in service for costs (device, installation, operation, etc.) to be recovered and the application benefits to continue.
- No desire to replace with the next whizz-bang feature.
- Many devices are owned by a single customerit might be cost-prohibitive for them to replace all their units en-masse!
Aeris began offering M2M data services in 1997 and its first customer began deploying AMPS devices in late 1997 and continued installations of their AMPS product for many years ... before migrating to digital devices near the middle of the last decade.
It is interesting to note that most of the AMPS devices installed in those early years were operating completely normally through February 18, 2008 when the AMPS Turndown caused them to go off the airsuch ten-year device lifetimes are unheard of in traditional cellular handset markets.
Indeed, in a few markets where Carriers continued their AMPS service for about three to six months after that AMPS Turndown date, the AMPS-Only devices continued to operate normally till the final service removal.
This device longevity requirementquite different from handsetshas very specific implications for the technology selection for an M2M application deployment.
To Be Continued ...
Next week, I will cover more factors that impact the technology selection process.
Tune in next week ... same bat-time, same bat-channel!