Electronic Design

Communications> Overview

If It’s Wired, Cut The Cord

Wireless is currently the most active and fastest growing segment of the electronics industry. If you said 20 years ago that some form of radio would dominate the attention of the electronic industry, you would have been laughed out of the country. Yet that's exactly what we're seeing today. Wireless is clearly a force of its own because it improves our mobility, flexibility, and convenience, as well as lowers costs in most applications. Rediscovering wireless is the best thing to happen to electronics since the invention of the microprocessor.

Over the course of the past 160 years, we've managed to wire and rewire the world many times over with an incredible variety of communications services. But while the wiring won't stop, the shift is clearly to wireless. New LAN extensions are now going wireless. The cell phone is gradually taking over as the most used telephone appliance, and the growing number of hot spots lets us connect to the Internet wirelessly almost anywhere.

Soon we will have wireless Internet access at home in areas where cable and DSL lines still aren't available. Short-range wireless technologies such as Bluetooth, ZigBee, ultra wideband (UWB), and RFID are emerging in unexpected places. Wireless is simply everywhere.

Two other important technologies will drive the communications sector in the coming year-broadband and voice over Internet protocol (VoIP).

Cable TV continues to dominate the broadband Internet connection business over DSL by a two-to-one count. But DSL is on the rise as major carriers cut prices and roll out the service in more locales. Despite the growth in this sector, only 20% of U.S. homes possess a broadband connection. Most PC users still rely on their dial-up connection. And that's even improving thanks to new accelerator services that supply software to boost speeds from about 30% to as much as five times the previous speed. AOL, Earthlink, and other ISPs now offer this software free as part of the service or at a nominal extra cost.

Major areas of the U.S. still lack high-speed Internet access. In particular, small cities and rural areas are under-served and become negatively affected without such service. Furthermore, the likelihood of them getting cable or DSL is remote. But soon these areas may enjoy a new form of high-speed Internet access, either power-line or broadband wireless.

The FCC has been testing broadband over power lines (BPL), or power-line communications (PLC). The data is modulated onto a carrier and the resulting signal is put on ac power distribution lines for transmission to and from homes. Data rates in the 500-kbit/s to 3-Mbit/s range are possible. With the distribution lines already in place, it's expected that electrical power utilities can offer a broadband Internet connection for significantly less per month than current cable or DSL lines. The great concern is that the spectrum of the signal in the 2- to 80-MHz range will produce unwanted and unacceptable levels of interference to other radio services. While that has yet to be proven, it could be a knock out factor for this unique and potentially successful technology.

Another possible broadband connection will come from what's known as Broadband Wireless Access (BWA). The technology is based on the IEEE's 802.16 standards. You can actually call it a wireless metropolitan area network (WMAN). Such a point-to-multipoint technology uses the 2- to 11- and 10- to 66-GHz bands to connect homes and businesses to the Internet. One version employs standard cable-TV-type modulation like 64QAM to achieve speeds up to 30 Mbits/s in a 6-MHz bandwidth. Other versions use 20- or 25-MHz bandwidth to push data speeds to 155 Mbits/s.

An important new version, 802.16a, uses a version of orthogonal frequency division multiplexing (OFDM) to help overcome the multipath and interference problems in non-line-of-sight (NLOS) situations. The line-of-sight (LOS) issue has been the primary roadblock to adopting BWA for "last mile" access. A huge number of homes did not have straight LOS path to the tower because of trees, buildings, or other obstructions. The newer OFDM versions minimize this problem. Speeds to 70 Mbits/s up to 30 miles distance are possible.

While wireless Internet service providers (WISPs) that provide this last mile connectivity already exist, expect the number to expand as new equipment supporting the standard becomes available. This standard will also no doubt become a form of back-haul connection for existing and forthcoming Wi-Fi hot spots. It may even become cell-phone back haul, which today is still mostly wired. Clearly it's another win for wireless as it fully serves new purposes, as well as supports existing services. Look for chips and equipment beginning mid-2004.

Since its first demonstration with a PC sound card and software in 1995, VoIP was thought to be a good idea. It's the most inexpensive way to implement long-distance telephone calls because you're digitizing and compressing the voice and then packetizing it over the Internet. Now that all of the kinks have been hammered out for the hardware and the software, the technology is finally ready for prime time.

At the end of 2003, over 25% of all new enterprise telephone-equipment shipments were of the VoIP variety. And that number is expected to rise to over 50% by 2006. On top of that, many local cable TV companies now offer VoIP phones to replace the traditional POTS connections. About 80% of the 90 million homes with cable-TV access can now get some form of high-speed Internet access, which gives them VoIP capability. Cable companies like AT&T and Cox already offer the service, with Comcast, Time Warner, and others not far behind.

And that's not all. VoIP is likely to find further application in wireless networks. Think of a headset attached to a laptop with Wi-Fi WLAN connections that enables VoIP phone calls to be made from hot spots. Even some cell-phone manufacturers and carriers are considering the implication of packet-based phone calls on a cell phone. Wireless broadband will provide yet another link for VoIP.

Overall, 2004 should be the big growth year for VoIP. The promise of converged voice and data is finally being fulfilled. The big question is whether the FCC will regulate VoIP just like traditional telephone service, thus removing one of its main advantages. And, what will the traditional phone companies do? They're already hurting from years of the telecom downturn. Many carriers in areas where VoIP is implemented are already noticing a decline in service. Combining that with the potential shift to fully wireless home phones could set the stage for some big changes from the telecom sector in the near future. Most carriers will also offer VoIP to stay competitive, so this technology's future certainly remains bright.

Hide comments

Comments

  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Publish