all- here are some notes from a friend who attended the IEEE meeting. i haven't had a chance to pick mark's brain on what the tone of the presentation was but there's some interesting stuff in there. > Attended IEEE Communication Society meeting in Denver. Presentation > was "Next Generation Wireless: Who Needs Base Stations?" Presented > by Dr. Tim Brown, University of Colorado at Boulder. > > The basic premise of his presentation was that cellular networks are > not well suited for high bandwidth services, and that ad-hoc 802.11 > WiFi networks were delaying the acceptance of 3G wireless. > > Some of the highlights: > > Economic challenge: > +What price for high quality, on demand, anywhere content...assume 1 > cent/kbps per minute > +Services cost: MPEG video at 1.2mbps=$12/min, or MP3 at > 128kpbs=$1.28/min > +This doesn't seem very affordable > > What can be done? > +Price=BW x bit-rate-price > +Reduce BW demand, Increase supply, or use an Alternate model > > The 3G challenge: > +Spectrum is expensive > +Base stations expensive > +Performance maybe only 2x of 2G cellular > +Handsets expensive > +Killer app is voice, 2G already does that well. > +So business proposition is uncertain > > The WiFi comparison > +Spectrum > +Base stations $200 > +Performance, proven multi megabit rates > +Handsets, many already own laptops w/wireless LAN cards > +2G is complimentary service > +Technology is already deployed > > Ad Hoc networks or community networks > +Cooperative wireless that emerges when wireless nodes are brought together > +Communication dynamic, has to adjust to people moving away > +Peer to peer, no one is in charge > +Capacity & coverage increase w/more users [i.e. more access points] > +Note, won't get coverage everywhere > +Security also an issue. > Where are these networks? > +Free nets in 50+ cities > example, Seattle; www.seattlewireless.net [showed map of several > hundred networks in downtown Seattle] > +Available in many airports, for like $8 day > +Neighborhood, Joltage franchise, joltage does billing; 100k nodes by 2005? > +Capacity is proportional to the number of base stations > FCC likes model, because they don't have to manage each little > piece of spectrum, no concern about companies not paying for > spectrum > > Technical issues [resource management, QOS, battery] > +Power issue, a 1 watt wireless lan card is a big percentage of > portable device > +Power & distance, power goes up with distance > +Routing in Ad Hoc networks > topo discovery > route choice > route maintenance > > Discussed Dynamic Source Routing, current status: > +power aware DSR design > +implemented in ns-simulator [open source simulator] > +implementing in laptop test bed using "click" > +Also showed simulation and experimental routing results. > > Conclusion: > +Wide area cellular networks are not well suited for high bandwidth services > +Wireless LAN networks complement wide area networks > +Can in-vision tri-mode handsets that can hand-off > +Ad hoc networks can expand coverage and capabilities of WLAN networks > +Routing layer has a role in conserving battery energy -- steve ulrich sulrich at botwerks.org PGP: 8D0B 0EE9 E700 A6CF ABA7 AE5F 4FD4 07C9 133B FAFC