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  • Self-Organizing Telephone Networks

Phones with Brains

Siemens is developing telephone systems that work without central switching. The phones communicate with one another independently — via the Internet.

F ranz Kneissl picks up the receiver and punches in a phone number. A phone next to him rings, and the answering machine switches. “One, two, testing,” says Kneissl, who is in charge of Micro Business Products at Siemens Com in Munich. Kneissl has just es- tablished a telephone connection over a dis- tance of 50 centimeters — a feat that few people would consider sensational. Neverthe- less, his demonstration marks a premiere. The two telephones aren’t connected via a tele- phone system; they’re linked using a LAN (Lo- cal Area Network), a technology normally used to network computers. Telephoning over Internet connections — the Voice over Internet Protocol (VoIP) — has been around for quite a while. What’s new, is that the wires on Kneissl’s lab table terminate in the jack for a LAN. The two phones are so smart that they can communicate with each other directly without a switching system.

In terms of business voice communication needs, the Siemens innovation is a paradigm shift. Calls have always been handled by cen- tral telephone systems linking phones in a star pattern, or via a central computer for VoIP calls over the Internet. In both cases, “dumb” phones do little more than convert sounds

into electrical signals, and vice versa. Func- tions such as three-party conference calling and call forwarding are organized by the cen- tral exchange.

According to Kneissl, the telephones of to- morrow will be different. They’ll organize themselves. That’s old hat on the Internet. Music file-sharing services, for example, don’t use a central computer — the data is on users’ personal computers, which exchange music files with one another. But Siemens is trans- ferring this principle — the technical term is peer-to-peer (P2P) — to telephones. The sys- tem needs a gateway (which Siemens offers) only when switching from a company’s inter- nal network to the public network. And even if this fails, company employees can continue to call one another. If a phone is out of serv- ice, another one automatically takes over the function of the answering machine.

This innovation from Siemens Com Enter- prise Systems, which is being tested in labs in Witten and Beeston, England, is appealing be- cause it’s a pure software solution. The sys- tem uses conventional VoIP phones. The dif- ference is in the software, which imbues the phone with intelligence and an identity. Via a telephone’s plug-in connection, the program


Internet / VoIP provider

DSL modem

Fax, etc.

searches the local network for other phones and automatically allocates the next free number to the first phone. The configuration is saved in the P2P network, which maintains the allocation of the numbers even if a phone isn’t working. No electrical outlet is needed as power is fed in via the LAN cable.

Only the software has changed, so the phones won’t cost more than comparable models. And by eliminating the costs of a switching system or a VoIP server, the system becomes even cheaper. That’s good news, particularly for small firms that can simply plug in their phones to their existing LAN. For now, the number of phones is limited to 30, for purely practical reasons. More users would mean the end of the cost savings over the conventional, centrally controlled solution.

And Kneissl has even bigger plans for P2P telephony — for example, with cordless WLAN phones. These could set up ad-hoc wireless communications networks with other WLAN devices or serve as access nodes for laptops. The technology will get really in- teresting when the music file sharing concept is taken to its logical conclusion. The phones could exchange contacts from the numbers stored in memory, for example. And video te- lephony, which has often generated great in- terest without taking off, could have another shot at success. With fast LAN networks, im- ages are transmitted without flickering, and there is a direct connection between two phones, without detours.

Public switched telephone network

Just plug it in. In a P2P network, devices organize themselves. Gate- ways provide con- tact with external users.


Telephone terminals



Gateway to external users


P2P WLAN mobile phones

Analog phone, cordless phone

What works for a company, can also func- tion for the public. Internet access providers looking to get into the telephony business could avoid the costs of expensive computing centers. The gateways that transfer data be- tween company and public networks could function as public relay stations. To get there, however, will require the development of improved algorithms for searching and data synchronization to serve larger numbers of users. Put it all together and the Internet, with P 2 P t e l e p h o n y , c o u l d o n e d a y b e c o m e a v i r t u a l , B e r n d M ü l l e r global telephone system.

High-Speed Internet for the Inuit

Greenland will have high-speed Internet and mobile communications this year. Technicians from Siemens and Tele Greenland braved atrocious weather to deliver the equipment.

G reenland has a raw climate and relies on boats and helicopters for transportation. Almost 85 percent of the world’s largest island is covered by an ice cap one kilometer thick. In summer, only the coastal areas in the west and south and some eastern areas are free of ice — and they are sparsely populated.

That’s why the island’s 57,000 inhabitants, who are almost all Inuit, need a first-class com- munications network. However, there are few underground copper cables connecting com- munities. A 1,500-kilometer directional radio system built in the early 1990s links the cen- trally located city of Uummannaq with Nanor- talik in the south via the capital city of Nuuk. Transmission towers fitted with parabolic dishes stand at 70-kilometer intervals along the link. And the Intelsat satellite provides the nodes at Aasiaat and Qaqortoq as well as Tele Greenland’s central network in Nuuk with transmission rates of 32 megabits per second (Mbit/s) for reception and 10 Mbit/s for trans- mission, which all users share simultaneously.

The satellites are also used for mobile com- munications, which were available at only 16 locations until recently. Residents also had on- line access at 56 kilobits per second (kbit/s) via modem and a copper cable connecting the ra- dio link base station and the users’ homes. “But that’s much too slow if you want to compare prices and quality on the Internet before order- ing a new snow plow, or for bringing online lessons to remote villages,” complains Ellen K.

Frederiksen, the prinicipal of the school in Qas- siarsuk, a village in the south with 110 inhabi- tants and 16 students. Frederiksen is eagerly awaiting the arrival of faster Internet access. There’s demand for e-mail and chat rooms, but also for better educational and career opportu- nities, medical care via telemedicine, e-busi- ness — and simply having mobile phones to make life safer for fisherman. Shrimp, cod and halibut are Greenland’s only exports.

During the short summer of 2005, techni- cians from Siemens and Tele Greenland brought in tons of equipment via ship to 46 re- mote communities — braving all weather con- ditions. Their cargo also included a crane and an off-road vehicle that can climb 45-degree grades. That’s how the ADSL-equipment and GSM base stations were delivered to well-insu- lated trailers that formerly contained only a bed, table and kitchen for maintenance techni- cians. To ensure the technology would be pro- tected from the cold and overheating at tem- peratures ranging from -20 to +20 degrees Celsius, systems for regulating heat exchange were also brought in. And GSM antennas were mounted on the directional radio link towers. “Now, all villages with 70 or more inhabitants have GSM reception and GPRS for data serv- ices. And from December 2005 every Green- lander will have a high-speed Internet connec- tion of up to 512 kbit/s,” says Frank Gabriel, head of technology at Tele Greenland. Gabriel ordered all the equipment from Siemens in

Denmark. The 43-year-old Dane was sure the new ADSL2+ transmission standard was the right choice, with its transmission rates of up to 25 Mbit/s and long range. At present, Gabriel can offer only 512 kbit/s for reception and 256 kbit/s for transmission, because the di- rectional radio link’s capacity is limited to 2 Mbit/s. If the link is further extended in 2006, Gabriel intends to use ADSL2+ to also offer tel- evision reception, high-speed Internet and te- lephony — all from a single source. But cost was the deciding factor, he says: “The equip- ment is less expensive than normal commer- cial DSL equipment, and it uses less electricity.”

Communities in the north and east of Greenland will have to cope without direc- tional radio links. To make full use of the costly satellite capacity, Siemens is supplying base stations that weigh only 2.7 kilograms each — the smallest in the world. The base stations are Internet-based and each one can simultane- ously handle seven telephone calls. Only the calls’ signalling is still done via satellite. The ba- sis here is a special switching technology called “local switching.” “This makes it possible to transfer calls directly from mobile phone to mobile phone, without a detour to the satel- lite,” explains Bjarne Roed, head of Communi- cations at Siemens Denmark. Local switching also eliminates those annoying voice delays via satellite. What’s more, the Inuit residents in the s p a r s e l y p o p u l a t e d n o r t h w i l l p a y l e s s f o r t h e i r N i k o l a W o h l l a i b mobile phone calls.

Linked to the rest of the world: Even in the most remote regions of Greenland, the lat- est wireless technology is helping to make life more manageable (photos above).

Pictures of the Future | Fall 2005


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