Introduction
The expansion of information services in the last decade has affected the way we live and work. At present, the Internet continues to grow faster than any other global infrastructure in history. Parallel to the Internet, we have witnessed a phenomenal growth in wireless communications. Third generation (3G) wireless systems are designed to bring wireless data connections to mobile users. However, economical and architectural considerations as well as data rates limited to 2 Mb/s, severely limit the ability of 3G to provide tetherless Internet connections to densely packed users such as in hotels or airports.
Short Range Wireless (SRW) is an alternative class of emerging technologies designed primarily for indoor use over very short distances. SRW is intended to provide fast (tens or hundreds of megabits per second) and low cost, cableless connections to the Internet. SRW features transmission powers of several microwatts up to milliwatts yielding a communication range between 10 and 100 meter. SRW will provide connectivity to portable devices such as laptops, PDAs, cell phones and others.
Short-range communications requirements lead to the emergence of a new category of networks referred to as personal area networks (PAN). Pan is designed for low power and low cost at the expense of range. New standards, such as Bluetooth and HomeRF, are being created to regulate short-range wireless communications. Ultra-wideband (UWB) is an emerging new technology that shows great potential for SRW applications. Unlike conventional wireless communications systems that are carrier-based, UWB-based communications is baseband. It uses a series of short pulses that spread the energy of the signal from near DC to a few GHz. Interest in this technology has been further heightened by the recent FCC announcement of notice of proposed rule-making concerning UWB usage, issued May 10, 2000. A ruling is expected shortly. In this brief article we review the basics of UWB and point out some of its promises as well as limitations.
Conclusion
UWB is an emerging technology, which exploits the spread spectrum concept to provide communications with very low power spectral densities. The proponents of UWB claim that it can function without interference with traditional communications systems. In addition to its application to SRW as mentioned in the introduction of this article, UWB has a wide variety of potential uses, from personal radar systems for detecting collisions to imaging devices that can see through walls. In this article we overviewed some of the basic features of UWB signals such as jam resistances and capacity. These and other fundamental issues need to be well understood before UWB can become a practical communications technology.
If you would like a copy of this article, which was published in NJCWT’s Winter 2002 Newsletter, please