WIRELESS communication technology offers organizations an array of potential benefits. And these benefits are showing up in all institutional and commercial facilities, from education and health care to commercial office, retail and hospitality.
But the technology is moving ahead at such a rapid clip — as are user needs and expectations for the technology — that maintenance and engineering managers making decisions on new applications face the tough challenge of determining the most cost-effective system for their departments’ needs.
The Center for Wireless Communications at the University of California, San Diego — www-cwc.ucsd.edu — has taken as its mission the creation “of a multi-disciplinary research and education environment conducive to the early identification of high-impact wireless communications opportunities.” The center’s research involves five key areas:
DIGITALLY CONTROLLED TRANSMITTERS. Next-generation cellular telephones will feature such advances as: full-screen, real-time video; web browsing; and a range of downloadable applications. These features will require much more power from batteries than do existing phones. This project’s goal is to reduce battery drain and increase battery life by developing new power amplifiers. Power amplifiers are electronic circuits that transmit the signal to the antenna of the cellular telephone.
Today, more than 90 percent of the power used to send a signal is wasted in the form of heat that stays inside the phone. Reducing this waste would increase the “talk time” of phones and dramatically improve the adoption of next-generation wireless services.
MIMO WIRELESS COMMUNICATIONS. One future goal of wireless systems is broadband access and services that are available seamlessly and virtually everywhere. Users will continue to demand this level of use because of the convenience, flexibility and enhanced productivity.
On the technical side, the trend is toward higher data rates, with a continued need for higher-quality services. New-generation systems are likely to support higher mobility, as well as bit rates greater than 5 Mbits/second. Broadband wireless local-loop systems also are likely to support rates of 2-155 Mbits/second.
But the goal of achieving these high data rates in band-limited radio channels is limited by multipath and fading. In light of these challenges, multiple input, multiple output (MIMO) wireless systems have many attractive and unique features, including array gain, interference suppression and avoidance capability, diversity gain and spatial multiplexing, all of which hold tremendous promise in addressing the enhanced link reliability, as well as high data rates that are required for future systems.
To maximize the benefits of MIMO systems, the center is researching issues such as channel estimation and equalization, space-time coding, and networking issues using multiple antennas to provide versatile, enhanced-capacity wireless systems.
