In an attempt to solve the question of how best to carry broadband services with consistently good quality from the network to the user at less cost, Siemens has developed a wireless technology, Skyweb, that approaches the "last mile problem" from a new angle.
Claudio Santacesaria, one of 12 Inventors of the Year 2002 at Siemens, says the answer lies in using only one radio signal in the millimetre wave range. "In so doing, a master antenna provides signals from the backbone network to several terminal antennae in apartment blocks.
"Known as point-to-multipoint, the new technology can be installed fairly quickly in densely populated urban areas, where it would allow new providers to make broadband services available at up to 30Mbps without resorting to leased-lines."
Santacesaria says that when applied to base stations in wireless communication networks, this technology can slash the number of required receiving antennae, since a single master receiving antenna is sufficient to act as a collector for up to 128 terminal stations.
When questioned about his invention, Santacesaria says the technology is proprietary, "coming more from the local multipoint distribution service (LMDS) camp than the wireless LAN camp". LMDS is a digital wireless transmission system that works in the millimetre wave range - from 24GHz to 40GHz. It requires line of sight between the transmitter and receiving antenna, which can be from 4km to 10km apart, depending on weather conditions. LMDS provides bandwidth in the OC-1 to OC-12 range, considerably greater than other broadband wireless services.
Santacesaria says Siemens' reference in standard terms is IEEE 802.16 and ETSI BRAN Hiperaccess, "in which field we have been active and hope to be able to bring standard compliant products soon".
Because the technology operates in line of sight, interference is not as important as in the lower frequencies, he adds. Still, very complex deployments require taking interference into account.
Siemens' technology can be used as a feeder for GSM backhauls (transmitting to a point which is cheaper to transmit to than the destination, and then transmitting back there), supporting radio relaying of native ATM (asynchronous transfer mode), but it can also be used to provide access to SME and multi-tenant residential buildings.
Wireless is fraught with security issues. Santacesaria says a sign on procedure is implemented, and claims security is much higher than any WiFi product. This is true for another reason: there is no public protocol involved. "In the standard version, 3DES encryption of all the traffic will be supported."
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