ITR: Generalized Ultrawideband for High Speed Networking

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Wireless networks are being successfully deployed at an exponential rate in public, enterprise and scientific networking environments. Such networks support roaming and dynamic environments, are easier and often cheaper to deploy than their wired counterparts and offer flexible configurations that can simply be modified. Several efforts are currently under way to develop high-speed wireless technology for wireless personal area networks (WPANs), wireless local area networks (WLANs) and storage area networks (SANs). This project is studying the theoretical underpinnings as well as the implementation challenges associated with two wireless high-speed networking technologies based on ultrawideband (UWB) communications. The first system is suitable for very high-speed networking applications where processing power consumption is less of an issue, such as storage area networks and home networks. The second system is an excellent match for power constrained consumer electronic devices in a WPAN, such as the scenarios envisioned by the IEEE 802.15.3a standardization effort in which the project team is actively participating. The project is making progress towards a demonstration of the latter technology in a wireless personal area network video-streaming scenario.In 2002, the FCC released the 3.1 GHz to 10.6 GHz band for UWB communications operating under part 15 of the FCC regulations. UWB communication systems use signals with a fractional bandwidth that is larger than 25% of the center frequency, or more than 1.5 GHz. Prior research established that UWB communication systems offer several potential advantages, including higher reliability, lower power consumption and ability to provide fine ranging information. Most importantly, they support overlaid communications, a key to addressing spectral congestion.The project recently produced a unified view of UWB schemes. ThisUnified view has led to novel UWB schemes with enhanced spectral efficiency. It has also simplified the design and generation of UWB pulse trains using broadband signal generation techniques. The resulting generalized UWB schemes rely on well-known baseband modulation schemes with existing economical chip level implementations, and adaptive agile spreading approaches that detect and avoid narrowband systems. They inherit the advantages of both UWB communications and those of the underlying baseband modulation scheme. The project pays particular attention to implementation issues, focusing on trade-offs between cost and complexity ofimplementation, and spectral efficiency and maximal achievable bit rates. For example, it examines novel one bit novel analog-to-digital and digital-to-analog conversion structures that are well matched to the baseband modulation schemes that the project focuses on, and the high bit rates envisioned in the applications of generalized UWB. These structures are finding applicability beyond the ongoing work.