Today over 110 million machines talk to one another without human intervention and most analysts predict that within the next 10 years, there will be more connected machines than the six billion people now walking the planet.
The millions of already connected machines perform a variety of different tasks, ranging from car sensors that enable pay-as-you-drive auto insurance to remote monitoring of industrial equipment to agricultural nodes that control irrigation based on the soil's dryness. This category of technology is typically called machine-to-machine (M2M) communications and represents significant new value involving dozens of industries, such as eliminating service costs with remote access, more efficient energy utilization through real-time monitoring, and creating new revenue streams by selling differentiated services.
The value of connected devices is growing every month, so let's explore what it takes to build an M2M system (Figure 1). (There are plenty of excellent case studies of M2M systems that use wired connectivity, from dial-up to dedicated T-1 lines. For the purposes of this article, we'll focus mostly on wireless communications, specifically on cellular communications. Today, many organizations are switching to cellular because of its increasing ubiquity, global standardization, and the fact that you can place a connected device almost anywhere, without requiring a local wired infrastructure.) You will need to consider the following five questions when developing your design:
What is your application and how much data will it collect ?
These answers factor into data transmission cost and, in many cases, the device's battery life. If you are using an Ethernet connection, the amount of data plays largely no role in communication cost because most plans offer unlimited usage. However, cellular and satellite communications are still metered (ignore what you read about all-you-can-eat plans from your cellular carriers—these are for consumers, not machines). You will want to optimize your application to collect only the data that is important by selecting which data to collect and what communication protocol to use. For example, TCP is great, but it can increase your bandwidth requirements. UDP can result in some packet loss, which may be acceptable to you in return for its lower total data transmission. If your device is in the field and not connected to a permanent power source, then battery life becomes an important consideration; the more often the device sends data or powers up or down, the more energy is needed. The key is to find the right balance that fulfills your data transmission requirements while meeting your business requirements—that unique mix of cost and device performance needs. For example, if your device is designed to send location information from a moving vehicle, you may need to send data every couple of minutes. If the vehicle in question is a piece of construction equipment, chances are that its location doesn't change that frequently and data need only be sent once a day or once a week.
Are your devices in a fixed or mobile environment ?
Answering this question will help you decide the right communication type. If you are capturing information from an automobile, for example, you are largely limited to cellular and satellite communication channels. If you are networking a building, you can collect data throughout the building using a ZigBee or other wireless mesh network, then use cellular or Ethernet as a backhaul to send the information to your central server for analysis.
The choice of communication channel depends on many factors, including the range over which communications must take place, the mobility that the machines require, and the availability of infrastructure resources. Both wired and wireless communications technologies are used to enable this connectivity and frequently compete for the same applications.
The easiest wireless connections to implement are those that are standards-based wireless, such as WiFi, Bluetooth, or ZigBee—these all have many modem providers and don't require the involvement of a network service provider. However, these wireless channels are short-range systems, operating over ranges from a few meters to less than a hundred meters. Applications that use one of these options thus tend to be confined to a relatively small geographic range, such as a factory or warehouse, although they may be mobile within that range.
Companies across a variety of industrial sectors are adopting Global System for Mobile Communication (GSM) cellular technology and using M2M communications to enhance their productivity, operational efficiency, and customer service. This growth is primarily driven by the widespread popularity of GSM within the M2M community. GSM has a clear and accelerated path forward—evolving from GSM to GPRS (with typical data rates of 50 Kbps up to 160 Kbps) to EDGE (typically 150 Kbps up to 400 Kbps) to UMTS and HSDPA (typically 250 Kbps, up to 480 Kbps)—and offers benefits such as mobility, ubiquity, and global standardization. More than 3 billion people currently use GSM technology in almost every country around the world, making it a low-risk choice. For fixed devices, using cellular wireless technology for data transportation can often turn out to be faster and cheaper than wired options because it doesn't require local infrastructure to connect the equipment to a centralized control. Moreover, the 'always on' feature of a cellular connection, key to efficient remote monitoring, is several times faster than dial-up for transmitting data and (unlike dial-up) doesn't have to create a new connection every time.
Is your deployment global, national, or regional ?
Are you a global company that will be implementing a global M2M system? Or are you focused on a small, regional deployment? Your answer helps you determine the kinds of technology partners you will choose, particularly if you are using cellular as a communication channel. In the cellular world, each country has a different set of mobile operators. Integration with a mobile operator is not a trivial task—the business terms, device certification requirements, and technical configurations vary across each one. So if you perfect your deployment for one operator in one country you'll require a new effort in the next country. There is no economy of scale. If you anticipate a multinational deployment, look for global service providers focused on the M2M space to make it easier for you to scale globally.
For smaller, regional deployments you may be best served by working with a local VAR. These specialists can provide you the expertise you need—configuring your device for the network, passing carrier certification, providing basic reporting—to get your deployment up and running smoothly. A good place to start is to search for VARs that distribute your chosen module (the modem inside the device). Web sties for some of the leading module manufacturers, such as Cinterion, Wavecom, Telit, Sierra Wireless, Enfora, SIMCom Wireless Solutions, and Motorola, all list their distributors.
How will you manufacture, distribute, and provision your devices ?
Will you build everything at a factory or put the devices together at the point of installation? Where will you complete your tests? Who will be responsible for activating the devices once they are in the field? If you aren't planning to take care of all these steps in-house, you will need a communication partner who supports your process. Connecting 1000 machines in one country is a management challenge. This complexity can grow and can be troublesome when you expand to 500,000 machines across dozens of countries.
Technical support, provisioning controls, billing, and reporting are just some of the operational issues you will need to consider when designing your solution. Fortunately, many of the M2M-focused service providers are now offering Internet-based software that provides insight into every aspect of device performance and gives you the ability to take immediate action.
Provisioning tends to be discounted very early on, but proves to be one of the most costly operational processes in any M2M system. In an effort to eliminate dead-on-arrival devices, you will want to perform end-to-end tests on every device before it reaches the end customer. If you're using a cellular communication system, this has cost implications because the device requires an active SIM to perform the test; you could end up paying for service while the device is sitting in the distribution chain. It is important to look for a service provider that understands and supports your testing and provisioning processes. Some service providers are now offering automated provisioning that eliminates many of the manual efforts.
What is the environment of the device ?
Is your communication modem going into an extreme environment, where it will experience tremendous heat, vibration, and excessive dirt? If so, you will likely need a design that eliminates vulnerable parts, such as a plastic SIM card (assuming that you're using cellular communication).
The SIM in a GSM device was designed with the expectation that the device and the service subscription are separate and, consequently, the SIM is removable. Moreover, the life of a SIM in a phone is relatively short—a couple of years on average. In M2M applications, however, it is common to expect a device and SIM lifetime of ten years or more, without the SIM ever being removed. In many cases, that lifetime may be spent in a harsh environment. SIMs made of traditional materials are not suited to these requirements. One solution is to use embedded SIM technology; rather than using a SIM encased in plastic and placed in a holder, the embedded SIM has common form factors (such as QFN 44) and is simply another chip soldered on the circuit board of the module (modem). Instead of expending manual effort to break a SIM from its plastic holder and place it in a device, a device manufacturer can use industrial pick-and-place machines to incorporate the SIM into it. All of this leads to lower costs and fewer mistakes because the completed device can go directly from assembly to test without manual intervention.
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