ISBN-13: 9781503290297 / Angielski / Miękka / 2014 / 94 str.
ISBN-13: 9781503290297 / Angielski / Miękka / 2014 / 94 str.
The National Aeronautics and Space Administration (NASA) is investigating alternative technologies to facilitate building communication networks for future Spaceports and Ranges. This reports documents an investigation conducted from October 2002 through September 2003 of an emerging communication technology known as Ultra Wideband (UWB) communication. Contained in this report is an overview of UWB communication technology, a survey of UWB equipment vendors, and complete details of the theoretical and experimental research that was performed during this emerging communication technology investigation. The summary conclusion of this report is that UWB communication holds great promise for augmenting future Spaceport and Range communication networks through enhancing short-range, high speed, wireless communication. This enhancement is accomplished through simultaneously integrating position-aware functions with traditional communication functions. UWB technology achieves this dual-function integration through using short impulses instead of the continuous waveforms common to most wireless systems. Because short impulses are used, UWB communication links are inherently immune to most multi-path interference, and also achieve better instantaneous spectrum re-use among users. UWB modulation also provides a Low-Probability-of-Detection (LPD) waveform with selectable security. UWB systems can therefore provide fade resistant, high speed data links wherever the presence of easily detectable wireless transmissions must be avoided, such as in specialized tactical situations. Despite the many theoretical advantages that exist for UWB modulation, much anxiety commonly arises with UWB emissions because of their ultra wide bandwidths. This characteristic especially causes concern vis-a-vis possible deleterious effects to narrowband legacy systems that typically operate at low link margins, such as GPS navigation systems, which often operate with link margins of only 1 or 2 dB. Though this concern has been addressed previously in Federal regulations through the inclusion of spectral emission mask requirements for UWB emissions, not all of the technical concerns have been settled. This report further researches some of these interference concerns by investigating UWB interference to, and UWB susceptibilities from, legacy wireless systems. The summary recommendation of this report is that UWB technology appears to hold many of the key advantages needed to tackle a number of wireless systems requirements needed in the future, provided it can co-exist successfully with both legacy narrowband wireless systems, and with other UWB wireless systems. Based on the demonstrated performance seen during testing, there is ample reason to believe that UWB wireless systems will be able to coexist with most legacy wireless systems. This report is a first step in understanding and assessing UWB's applicability for supporting the communication needs of future Spaceports and Ranges."