外文翻译超宽带技术的短期或中期范围内的无线通信Word下载.docx

1、 外文文献原文Ultra-Wideband Technology for Short-or Medium-Range Wireless Communications Jeff Foerster, Intel Architecture Labs, Intel Corp Evan Green, Intel Architecture Labs, Intel Corp Srinivasa Somayazulu, Intel Architecture Labs, Intel Corp David Leeper, Intel Connected Products Division, Intel CorpI

2、ndex words: UWB, wireless, communications, LAN, PAN ABSTRACT Ultra-Wideband UWB technology is loosely defined as any wireless transmission scheme that occupies a bandwidth of more than 25% of a center frequency, or more than 1.5GHzThe Federal Communications Commission FCC is currently working on set

3、ting emissions limits that would allow UWB communication systems to be deployed on an unlicensed basis following the Part 15.209 rules for radiated emissions of intentional radiators, the same rules governing the radiated emissions from home computers, for example. This rule change would allow UWB-e

4、nabled devices to overlay existing narrowband systems, which is currently not allowed, and result in a much more efficient use of the available spectrumDevices could, in essence, fill in the unused portions of the frequency spectrum in any particular locationThese recent developments by the FCC give

5、 Intel a unique opportunity to develop equipment that could potentially take advantage of the vast amount of usable spectrum that exists in the wireless space, and that could provide an engine to drive the future high-rate applications that are being conceived throughout this industry Intel? Archite

6、cture Labs IAL is currently researching UWB technology in order to better understand its benefits, limitations, and technical challenges when used for high-rate communicationsThis paper introduces the reader to this technology, from potential applications to regulatory hurdles, to possible implement

7、ations and future challenges.INTRODUCTION Ultra-Wideband UWB technology has been around since the 1980s, but it has been mainly used for radar-based applications until now see 1 and the references therein, because of the wideband nature of the signal that results in very accurate timing information.

8、 However, due to recent developments in high-speed switching technology, UWB is becoming more attractive for lowcost consumer communications applications as detailed in the “Implementation Advantages” section of this paper. Intel Architecture Labs IAL is currently working on an internally funded res

9、earch project whose intent is to further explore the potential benefits and future challenges for extending UWB technology into the high-rate communications arena Although the term Ultra-Wideband UWB is not very descriptive, it does help to separate this technology from more traditional “narrowband”

10、 systems as well as newer “wideband” systems typically referred to in the literature describing the future 3G cellular technology. There are two main differences between UWB and other “narrowband” or “wideband” systems. First, the bandwidth of UWB systems, as defined by the Federal Communications Co

11、mmission FCC in 2, is more than 25% of a center frequency or more than 1.5GHzClearly, this bandwidth is much greater than the bandwidth used by any current technology for communication. Second, UWB is typically implemented in a carrierless fashion. Conventional “narrowband” and “wideband” systems us

12、e Radio Frequency RF carriers to move the signal in the frequency domain from baseband to the actual carrier frequency where the system is allowed to operate. Conversely, UWB implementations can directly modulate an “impulse” that has a very sharp rise and fall time, thus resulting in a waveform tha

13、t occupies several GHz of bandwidthAlthough there are other methods for generating a UWB waveform using a chirped signal, for example, in this paper, we focus on the impulse-based UWB waveform. but, first, a breakdown of how this paper is organized.WIRELESS ALTERNATIVES In order to understand where

14、UWB fits in with the current trends in wireless communications, we need to consider the general problem that communications systems try to solve. Specifically, if wireless were an ideal medium, we could use it to send.1. a lot of data,2. very far,3. very fast,4. for many users,5. all at once.Unfortu

15、nately, it is impossible to achieve all five attributes simultaneously for systems supporting unique, private, two-way communication streams; one or more have to be given up if the others are to do well. Original wireless systems were built to bridge large distances in order to link two parties toge

16、ther. However, recent history of radio shows a clear trend toward improving on the other four attributes at the expense of distanceCellular telephony is the most obvious example, covering distances of 30 kilometers to as little as 300 metersShorter distances allow for spectrum reuse, thereby serving more users, and the systems are practical because they are supported by an underlying wired infrastructure