ding playback for coaching, or viewing the re-creation of an event Automating the home environment, such as keyless locks and rooms that adjust light, temperature, and music sound levels Automatically adjusting camera focus and motion-tracking for matching digital effects in motion pictures Chapter 15 WMANs, WLANs, and WPANs Creating automotive collision detection systems and suspension systems that respond to road conditions Performing medical imaging, similar to x-ray and CAT scans Performing through-wall imaging for detecting people or objects in law- enforcement or rescue applications The Future of UWB Proponents of UWB see a future in which UWB technology will reach ubiquity in LANs and PANs. In addition, UWB has the potential to penetrate WAN markets by using ad hoc or managed mesh networks and to eventually make competing tech- nologies such as W-CDMA and GPRS obsolete. UWB could become the dominant technology in WPANs, WLANs, and WWANs. However, a limiting factor to UWB's dominance in the worldwide WAN is unification of global wireless spectrum allo- cation standards. The greatest challenges UWB faces are regulatory issues and deadlocked UWB standards disputes in the IEEE. Some have raised doubts about the future of UWB. Some industry observers suggest that regulations in Europe will be substantially more restrictive than those applied by the FCC. Japan is likely to be even more conservative. Stiff regulations would limit UWB to a smaller slice of spectrum and reduce its speed and range. It would then have more trouble competing against faster versions of Wi-Fi. In addi- tion, IEEE 802. lln is expected to be established by 2007, offering a theoretical limit of 110Mbps to 200Mbps. Accounting for overhead, the resulting throughput will be some 45Mbps. Although UWB can support 480Mbps at short ranges, it would drop off with distance-particularly if the regulations limit the spectrum it can use. By the time it goes across a room, the data rate of UWB could be more like that of 802.11n. However, UWB vendors cl