Wired Won't Go Down Without A FIght

electronic design
http://electronicdesign.com/Articles/ArticleID/19068/19068.html
06-19-08, by Louis E. Frenzel

The trend toward a wireless world will forge on, but don�t expect to see the demise of wires. We could even see some new wires, virtually all of which will be glass or plastic rather than copper.

The well-entrenched plain-old telephone systems (POTS) or public switched telephone network (PSTN) aren�t going away. Major phone carriers AT&T and Verizon, as well as smaller carriers, will continue to maintain these systems despite the declining number of wired subscribers. They won�t go away, and in many cases, they will still support advanced services like DSL broadband lines.

Most new wiring will be fiber. Just look at the growth of Internet Protocol TV (IPTV). The only medium really fast enough to handle high-definition video, compressed or not, is fiber. That�s why wiring for IPTV services like AT&T�s U-verse system and Verizon�s FiOS system consists of passive optical networks (PONs).

Most home networks will maintain a wired instead of a wireless medium. Video is the justification. IPTV providers have selected wired media for their IPTV systems simply because wireless continues to be spotty and less reliable. While data rates of 802.11n Wi-Fi and Ultra-Wideband (UWB) are fast enough, the range is short and data rates decrease with range and problematic environments.

To ensure that all customers get reliable connectivity in the home without service calls, Verizon selected the MoCA home-networking solution, which uses the installed base of cable TV coax as the medium. AT&T went with the HomePNA wired system using the coax cable as well as the installed telephone wiring. No wireless. UWB and 60-GHz WirelessHD systems will serve in short-range connections, while wired systems, including ac powerline systems, will provide the most reliable solution without the truck rolls.

In very high-speed systems, wired is still faster than wireless. The highest data speeds are achieved over fiber. Data rates exceeding 100 Mbits/s are easy to attain. This is still hard to do in wireless over any distance with full reliability. Keep in mind that the radio carrier must be higher than the data rate by a factor of 10 or more.

Name one wireless system that can achieve 1 Gbit/s. Few exist, and those that do operate in the millimeter wave (>30 GHz) or optical bands over short distances. Progress continues in wireless, but if speed is uber-critical, fiber is where it is at. That said, fiber is the only choice for 100 Gbits/s. Such an extreme data rate has already been achieved over many kilometers of fiber. As new and better optical modulation methods and dispersion compensation solutions emerge, speeds exceeding 100 Gbits/s will become easier.

These fiber systems will be our new Internet backbones and, eventually, other wide-area network (WAN) and metro-area network (MAN) solutions. Already, the IEEE Ethernet group is working on a 100-Gbit/s version for local-area networks (LANs) and MANs. A wireless version simply is not in the cards.