Ad hoc networks demonstrated to date operate on pre-assigned portions of the spectrum, which limits their connectivity and the efficiency with which the available spectrum is used. Ad hoc networks are assumed to work independently of the Internet and attach to it only through a few access points. Furthermore, wireless routers are considered to be different from Internet routers, and routing in ad hoc networks today is independent of spectrum management or the availability of wired links.
The SWAN (Spectrum-Agile Wireless Available Networking) project addresses the above limitations by enabling wireless spectrum utilization in far more efficient ways than it is possible today, and by making wireless links an integral part of the Internet. The expected results in SWAN include:
(a) Wireless Available Networking: SWAN will develop an architecture and protocols that transform the concept of ad hoc networking into wireless available networking, such that Internet routers use radio links opportunistically, in much the same way as wired links are used today by routers.
(b) SMASH (Statistical Multiplexing of Available Spectrum Heuristics): SWAN will develop algorithms, protocols, and etiquettes for the dynamic sharing of the available spectrum based on the statistics of information flows. This way, routers determine in a distributed fashion which portion of the spectrum they can use.
(c) Policy-based Routing: SWAN will develop the first policy-based routing protocols for wireless enabled networks, with which routers manage the topology and paths of wired and wireless portions of the Internet based on administrative, quality-of-service, and spectrum-utilization policies.
