A 3G radio is rapidly becoming standard equipment on embedded devices. 3G technology offers much faster download and upload speeds compared to older cellular technologies and, for the first time, allows for simultaneous data and voice transmission. With these and other benefits, more OEMs are finding 3G radios make their devices much more capable and powerful.

Just as there are infinite applications for 3G technology, there are infinite ways to deploy it. Having so many options seems like it would make deployment easier, but it actually raises complexity. This article will walk you through key decisions to help you best integrate 3G technology with your existing hardware and software.

What is 3G?
The term 3G simply refers to the third generation of wireless telecommunications standards, including mobile voice and video calls and data transfer. There are several standards; however the most common are the CDMA standards known as CDMA2000 which includes CDMA2000 1xRTT, 1xEV-DO, 1xEV-DO Rev. A, 1xEV-DO Rev B, and the GSM standards known as WCDMA which includes UMTS, HSDPA, HSUPA, and HSPA+.

The most noticeable advance in the third-generation technology is speed. (See Figure 1 below. Comparison of data upload speed by network type.) Data throughput speeds are much improved. Download speeds of up to 14.4 Mbit/s are possible and capable of upload speeds up to 8 Mbit/s.

Figure 1. Comparison of data upload speed by network type.

Of course, performance varies substantially from device to device and even network-to-network. Generally 3G has come to indicate speeds of between 384kbits/s and 10Mbits/s.
To get a better understanding of how wireless technology has improved, let's look at its growth through a consumer application. With 2G wireless technology, it could take as much as 40 minutes to download one three-minute MP3 file. With 2.5G technology, the download time for that file may drop to just nine minutes. With 3G technology, the download time drops to as little as 11 seconds.

That's a dramatic increase in speed, though one of the biggest advances in 3G is that, it's possible to send voice and data simultaneously over the same wireless connection. This advance opens the door for many new potential applications.
Potential 3G applications

The uses for 3G technology are limitless, but here are a few common applications helped by its capabilities and capacity.
Handheld terminals. Handheld data collection and inventory devices are commonly used by factory, warehouse and field workers. These employees often also have to carry a two-way radio or cell phone to contact dispatch or other staff.
3G technology, which allows for simultaneous voice communication and data transfer, allows you to combine both of those devices. Doing so could potentially increase worker productivity and lower device and communications costs.

Device requirements vary by application, but include an audio codec supporting approximately 12.2 K/bps for voice. You also need to consider how much data the workers will need to send. Simple inventory tracking devices may require relatively little data capacity.
Other field workers may need to transmit or download photos. Plan to provide appropriate bandwidth to meet their needs.

Kiosks. Video kiosks provide dynamic information and services and are increasingly in use in more public places. For example, a Kiosk can help generate interest in activities at tourist attractions. Adding video conferencing capabilities could help even more. Tourists who need help could get one-on-one assistance without the need for individual staffing at each kiosk location.
Adding a 3G radio to the kiosk could enable this assistance. Video conferencing requires 30 fps QVA high-quality video stream for download and 15+ fps VGA high-quality video stream for upload (limited by upload speed).

Surveillance systems. Surveillance systems can also receive a major upgrade using 3G wireless technology. Real-time video improves performance of video surveillance by providing a continuous monitor of activity. Using 3G connectivity, the camera system will have sufficient band width for video and yet be protected from being disabled by severing a network cable. This application requires live streaming real-time video up to 15+ fps with QVGA or better resolution.

Do you need 3G?
Is 3G worth the investment for your particular project? If you need simultaneous voice and data transmission " earlier technology supports only one or the other at a time " and relatively fast data speeds, the answer is "yes." There is no one particular "best way" to add 3G capabilities to a device. There are far too many options for there to be one recommended path. There are three different types of 3G radio form factors, all with unique benefits and design considerations.

Software integration isn't straightforward either. It's highly variable based on your radio selection and how you will use 3G in your application. And there are dozens of wireless service providers with two different network types. The choice among these is largely affected by where you will use the device.
Finding the "best" approach for your device involves understanding your needs and goals and carefully evaluating your choices at each major decision point in the design process. Here are five steps you can follow to maximize your success integrating 3G into your device:

Step 1: Ask the right questions in the requirements phase
There are a few key questions you'll need to consider during the requirements phase.
1. What cellular networks will be available for your device?. Different radio technologies are supported in different areas of the world. About 85% of the cellular systems in North America use CDMA.
GSM is the international standard used in much of Europe, Australia, Asia and Africa. Different parts of the world may also use different frequencies for their radio bands. Your answer to this question will help you define which radio standard your device needs to support and what radio you will choose.
2. What are the projected annual shipments of your device?. Your projected shipments will influence how embedded your radio will be in your device. The three common cellular design implementations are air cards, embedded chipsets, and embedded radio modules. The choice is a trade-off consideration between development cost, unit cost, time to market and risks.
An embedded radio chipset will be designed into your circuit-board and typically licensed from a company like Qualcomm. An embedded mini-module is an off-the-shelf wireless module with pre-integrated, pre-tested system software. An air card or dongle is a free-standing radio that plugs into your device externally through a USB interface.

If your device is expected to ship in high-volume over 100,000 units, you should consider an embedded on-board radio chipset. The R&D investment, as well as radio certification costs required to embed a radio are high, but these radios require the least space and have the lowest unit cost.
For low-volume projects of less than 1000 units, an air card or dongle radio is often a good choice. R&D and certification costs are minimal " in some cases, it's practically plug-and-play " but individually these radios need the most space and cost the most.

For production rates of up to 20,000 to perhaps 100,000 units, embedded radio modules are ideal. The embedded module is an enclosed device with the radio chip set sans antenna. The radio modules are certified and interface over USB using a PCI Express interface forma factor.
The modules can be easily integrated into a device while allowing flexibility in antenna placement. The benefits of the radio module include allows for small form factor designs, certification at the module level reduces certification costs and risks, and moderate design efforts for software and hardware.

The modules I/O can include data, audio, and GPS support making the modules ideal for feature rich devices. Do keep in mind that if you need to use the 3G radio for voice calls, an external radio is not a good choice " even for low-volume projects. A large amount of custom work is needed in order to route the voice paths onto external radios.
3. What is the lifespan of your device?.Be aware that just because you don't need the high-speed capability of 3G now, you may need it in the future. Consider the data plan cost over the entire life of the device.
Older technology (2G, 2.5G) may not maintain its cost advantage over the lifespan of the device if network operators offer incentives to move traffic onto the newer 3G infrastructure. Additionally, network operators may phase out older technologies.
 

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