Nokia wireless rooftop networking can be qualitatively distinguished by its mesh mode of operation. This simply means that every node acts as an IP router (digital radio modem and Air OS) for the whole network, what is known as
multipoint to multipoint in the lingo. Thus problems such as the need for lie of sight between a main access point and distnce limitations within any given footprint are obviated.
The Nokia system operates off 'Airheads'(!) that have a fixed or wireless connection to the rest of the network, and each of which can accomodate up to 40 connctions. The network actually improves as it grows as the number of routers increases the distance and power required of the transmission contracts.
These problems can also be overcome in 802.11 networks by use of the peer to peer mode (some
software will probably help)and the construction of diy antennas - which have been used to cover distances up to twelve miles - but for the moment at least are less reliable.
The other advantage to 802.11b is that there are alr4eady many nodes in existence, particularly in the anglophone world such as New York, SF, Seattle and London. Furthermore the basic equipment is very cheap, with cards available for $70 and a linksys access point/bridge costing only $100.
