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9.1. How Is UWB Networking Different?In many ways, the networking protocols that should be used for UWB networks are similar to those appropriate for other wireless networks. However, the properties of the UWB physical channel necessitate some changes, especially in data link layer protocols. Further, to optimize performance the design of the data link and network layer protocols should account for the characteristics of UWB physical links, and likely applications and deployment scenarios for UWB networks. For directly connected nodes, the basic requirements and objectives for the data link layer protocols do not change with the introduction of UWB technology, namely, ensuring reliable communications across a link, minimizing the likelihood of channel contention, providing flow control, and supplying basic addressing information. However, in the context of data link layer protocols, notions of a channel, methods for detecting transmission activity by other nodes, and self-interference are all affected by the choice of link parameters, including modulation schemes. The specific schemes used for these protocols in a UWB network must reflect the unique properties of UWB communications links. The fundamental requirements of the network layer also do not change for UWB. UWB networks will likely often be ad hoc in nature. The mechanisms to best meet the requirements of the network layer for wireless ad hoc networks are a focus of current research and are certainly not well understood for UWB, which is a nascent networking technology. There are opportunities to leverage both radio link characteristics, using cross-layer design, and application requirements to optimize network layer protocols. For example, UWB devices in an ad hoc network may self-organize themselves into hierarchical clusters in ways that consider mutual interference, power conservation, and application connectivity requirements. |
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