Wireless Technology Survey
Apr 15 '00
Wireless Technology Survey
Warning! The following opinion is a survey about wireless technologies that are available today and are likely to be available in the near term. This opinion will not directly help you pick a phone. It will help you understand some of the differences amongst the various wireless voice and wireless data technologies that are available and becoming available. This opinion is primarily a look at the competing technologies for wireless data.
Analog vs Cellular
Generally, people have heard that there is a difference between analog and digital cellular phone networks. The distinction between something that is analog and digital is a fairly common idea to different types of electronics, not to mention clocks. Remember when you had to wind your wristwatch (kids – ask your parents what I’m talking about)? That was an analog clock – it provided a constant stream of data as the clock unwound, pushing the hands around the clock face. Digital technology wraps information into individual packets that are pieced one at a time. In the best digital technologies, these packets arrive so quickly that you perceive them as being continuous.
Physical Transport Protocols
So wireless phones can work over either analog or digital technologies. The point I want to make here is that in a wireless network, there is an underlying physical transportation method that can be controlled using either an analog or digital protocol. This is analogous to the wired phone system’s protocol for pushing information along wires and optical fiber. In the wireless world, we have electromagnetic waves traveling through airspace or even through walls, unconstrained, in general, by direction. In the wired world, we have electricity or light traveling along predefined cables. Both systems need to have a protocol for controlling moving information from one place to the next.
For phones, this is something like the POTS (Plain Old Telephone System, really). For the Internet or a local office wired data network, the physical transport protocol will be something like Ethernet, or ATM. In the wireless world, these different physical transport protocols are generally lumped together into 1st Generation, 2nd Generation, 2.5 Generation, and 3rd Generation. 1G primarily refers to analog technologies and, in particular, to voice traffic and Cellular Switched Data (CSD). 2G refers to a set of common digital technologies: TDMA, GSM, and CDMA.
2G -- Digital Technologies
All of the 2G and later technologies are digital technologies. It’s common knowledge that the United States is behind in terms of rolling out wireless technologies to customers. The world leader is Japan, followed by Europe. Japan has the advantage of a relatively small area, so that it costs less to install the wireless infrastructure necessary to reach the entire country. In the United States, for instance, competing wireless networks have struggled to get coverage across the entire country. Japan and Europe both have the advantage over the United States in that they decided to leapfrog the costs of upgrading their wired infrastructure by jumping directly to wireless voice AND data networks, so there is a much greater demand for the data applications in Japan and Europe that drive the development of new wireless technologies. It’s also worth noting that Japan and other parts of the far east, notably Hong Kong and Singapore, are well-known for being early adopters of technology. These places are at least two to three years ahead of the United States in terms of wireless data applications that are available. It’s also worth noting, however, that the United States, while behind in the deployment of wireless networks, is at the forefront of developing the technologies for those wireless networks.
Keep in mind that about 78% of the planet has never even made a phone call, much less ordered something over the Internet, or read their email on a cell-phone. Wireless technologies are big business and countries in Africa, South America, and Asia are increasing their wireless phone and data users at a very fast rate. We will continue to see an explosion in new wireless technologies for years to come.
2G technologies around the world
Japan uses CDMA technology. Europe uses GSM technology. The United States has a majority of TDMA networks, but actually sees all three technologies in use. TDMA stands for Time Division Multiple Access. TDMA allows multiple users’ data to coexist by carefully timing transmissions, interleaving the data from each user in a repeating pattern. GSM also uses a variation of this time-division algorithm. CDMA stands for Code Division Multiple Access. CDMA provides a larger number of users’ data to coexist than time-division methods by applying a code that identifies each individual user and then spreading all of the users’ information across a number of different frequencies.CDMA is also newer than TDMA and GSM and provides faster connection speeds. These technologies generally have transfer rates ranging from 9.6 kbps to 19.2 Kbps, though the newest installations get as high as 64 Kbps for TDMA and 84 Kbps for CDMA.
What's coming next?
In the future, the TDMA and GSM physical transport protocols will give way to technologies like GPRS (General Packet Radio Service) and the even faster EDGE (Enhanced Data GSM Environment). These technologies run in the range 115 to 171 Kbps and up to 384 kbps, respectively. GPRS will be much easier to provide, as it will, in general, run on the existing infrastructure. EDGE’s distribution is in some doubt, as it will be much more expensive to install and the difference between GPRS and EDGE may look inconsequential by the time carriers are able to install it. These are the 2.5G technologies. GPRS will probably be deployed by the end of 2000 in Europe. When it gets installed in the US is difficult to judge. It depends greatly on what US carriers decide about both consolidating services and changing technologies.
For 3G technologies, we’ll see CDMA give way to W-CDMA (Wideband-CDMA), providing 2Mbs speeds. Japan should have this by the middle of 2001. That would be a wireless technology as fast as the best cable modems. European operators are expected to move to TD-CDMA (Time-Division-CDMA) and reach similar speeds sometime in 2002-3. Who knows what will happen in the US. There’s a dark horse in the picture as well. It’s possible that in a few short years, the entire world will have access to 10 Mbps low earth orbit (LEO) satellites. Bill Gates, for instance, has been selling Microsoft stock and investing in a company that will launch such satellites. There's some doubt, mind you, about whether this company, Teledisc, will succeed.
What about data?
So far, I’ve primarily discussed the physical transport protocol that enables phones to send and receive information. This is sufficient for voice communication, but for passing around data, there needs to be a data protocol layered on top of the physical transport. In the Internet world, this is equivalent to the way that TCP/IP or Netware allows computers to actually understand each other while Ethernet or Token Ring allows computers to physically send information to each other. Why do I care about data being passed to my phone? Phones are just for talking, right? Not anymore. Imagine combining your phone book with your phone so that you could look up someone and press a button to call him or her. Likewise, imagine capturing the phone number of anyone calling you directly into a database. Ranging farther afield, what if you could check stock quotes, make travel arrangements, get directions, be notified of sales as you walk through a mall, carry around digital cash that you used to pay for everything from parking tolls to sodas to, well, anything. Many of these applications exist right now in Japan, Europe and, to a lesser extent, in the US.
Then there are the corporate uses. Delivery drivers and repairmen already use propriety systems for capturing information to a database immediately. When your phone and your personal digital assistant merge together, you gain the ability to instantly reach your corporate database whenever you need to. Forgot to bring the slide you need for a presentation? No problem! Use your wireless device to grab it from work. Then use your wireless device to ‘beam’ it directly to the projector.
So we want to be able to move data around wirelessly. The 1G analog voice system, CSD, allows users to turn their phone into a modem for their computers. By connecting the phone to a computer, the computer can dial-up a service, like AOL or any other ISP. Analog networks can now also make always-on data connections using the Cellular Digital Packet Data (CDPD) protocol. OmniSky, for instance, offers an email service for Palm V users who’ve been equipped with an analog wireless modem, using CDPD.
The wireless Internet to come
It’s important to note that the wireless world has not converged in terms of standards at this point the way the wired world has. In the wired world we have the Internet, which, in general, allows any computer in the world to communicate with any other computer. This works, in part, because just about everyone has adopted the IP protocol which provides a consistent way for computers to communicate, regardless of what types of wires are used to send the data from one computer to the next. This also works because, on the Internet, web servers and web browsers have become standard for providing and receiving information. Note that there are still plenty of proprietary data services in the wired world. AOL, for instance, provides content that’s only reachable if you’re signed into the AOL network. Plenty of corporate data systems are non-Internet enabled and only work if you’re signed into the company’s wired network.
The OmniSky service mentioned above uses CDPD over an analog network. This is not a universally adopted standard. There are many methods that have been developed to provide methods of wireless data delivery. These include:
Short Message Service (SMS): Built on top of GSM, TDMA, or CDMA. This provides one-way or two-way connections. It’s like text paging, providing about 160 characters. In Europe, this technology has really taken off with two to three billion messages sent every month.
Mobitex and RD-LAP: These are data-only networks that combine the physical and data transport protocols into one proprietary system and then build further proprietary systems for data delivery. The Blackberry messaging service, which provides email and calendar services and is receiving rave reviews, runs on either Mobitex or RD-LAP. The Palm VII wireless connection runs on the Bell South Mobitex network.
Phone.com: This company created the concept of a micro-browser. Similar to a web browser, the micro-browser resides on a wireless device and allows one to access a variety of data services. Phone.com also created HDML (similar to HTML) for encapsulating concept in a standard way across wireless servers. Phone.com licenses the software necessary to create and serve content, so this is not an open standard, though it is certainly a step towards consistent data delivery methods.
There is a huge movement, however, to consolidate wireless communications around a universal standard.
Who's setting the standard?
To that end, thousands of companies came together to form the WAP (Wireless Application Protocol) forum. The WAP standard encompasses WML (Wireless Markup Language) and all of the protocols involved in serving data in a secure way over wireless networks. Furthermore, the WAP forum allows for communication between wireless networks and the Internet and is working with other standards committees to converge the wired and wireless worlds. In the next few years, the distinction between the wired and wireless data world will fade as devices in either realm will contact the same servers for information. The data will have to be displayed differently depending on the device which receives it. This is not a simple task, but the WAP forum is working on standards that help reduce the complexity involved in developing content for all of the different types of wired and wireless browsers that might receive it.
Pico Nets!
When we discuss wireless data services, however, we should not limit the discussion to the concept of client/server computing. Some of the most exciting advances will come from the concept of pico-networks, designed for communication between two wireless-enabled objects that are in close proximity. Imagine that there’s no wire between your cellular phone and an earpiece. Nokia has released just such a device that uses the new Bluetooth standard. Imagine that you take your computing environment with you wherever you go with a small device that knows how to receive input from a wireless-keyboard, knows how to print information to a wireless-printer, and uses something like the Apple Airport to connect to the Internet. The office of the future might have a monitor, keyboard, and mouse that look like a laptop of today, but communicate entirely with the information stored in the wireless device that you keep at your belt or in your pocket.
Let’s get really wacky. Imagine that we could print circuits into paper and embed them into food packaging. A microwave could use a small magnetic field to generate a small voltage in the paper-printed circuit and then receive the instructions for cooking the food. Sound crazy? The paper circuits are being printed today. It’s just a matter of building the microwave – or building the washer which tells you how to wash your clothes – or building the automatic readers which will take away a lot of the error in inventory management. These things are coming, and they’re coming fast.
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Epinions.com ID:
arenson9
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Member: Andrew Arenson
Reviews written: 3
Trusted by: 2 members
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