Östen's curve

Mäkitalo officially became a member of the NMT group in 1974. He had been keeping track of what was being done before that, and had also taken part in some meetings, but now his thinking began to make a clear impact on the NMT project. He kept repeating how important it was not to be bound to any technology that would be obsolete before the system became operational. Mäkitalo illustrated this by drawing a curve (eventually known as “Östen’s curve,” after it was named by a Danish member of the NMT group, Søren Nielsen) demonstrating that, if one relied on continued development of computer circuits and similar advances, it would be possible to take several technological steps forward in the same process.

“At that time we had not yet heard about Moore’s law [which in its original version states that the number of transistors that can be fitted on to a chip grows exponentially and doubles every 18 months] but intuitively I had the same approach,” Mäkitalo recalls.

His approach, daring to rely on technology that did not yet exist, ran counter to established ways of thinking not only for Televerket but also for the suppliers. “At the meetings, we had to listen to people telling us how naive we were to base our system solution on microprocessors. It would be impossible to use them in terminals because of the current they demanded. And neither would they work in the temperature ranges that mobile terminals might be exposed to,” Mäkitalo says.


Another important point of departure for Mäkitalo, as previously mentioned, was small-cell technology: “I had noticed that mobile phone users rarely moved more than one or two kilometers during a normal call. This meant that in the large towns the system did not have to struggle with base stations that covered large areas. A radius of a couple of kilometers was enough. Then frequencies could be used more efficiently.”

Haug adds: “We soon realized that a small-cell system would offer major benefits, but would also involve major complications, in the signal system for instance. The NMT signal system undoubtedly became a lot more complicated than anything that had been used up to then in mobile telephony. It was not until we got confirmation that we could use the ‘intelligence’ in the microprocessors that we were really sure the small-cell system was realistic.

“It was also important that we never saw mobile phones as high-status gadgets for top businessmen and playboys. Perhaps they would not end up in everybody’s hands but whatever happened they were going to be very useful for a large group of businessmen, tradesmen and people whose work took them around a great deal.”

Today, Mäkitalo believes he and his colleagues would never have been allowed to get away with what they were doing if their bosses had known how big mobile telephony was going to become. “They would never have placed it in the hands of a bunch of fairly young engineers,” he says.

Author: Svenolof Karlsson & Anders Lugn

Testing of a central processor in a prototype lab

Testing of a central processor in a prototype lab

Testing of a central processor in a prototype lab

Testing of a central processor in a prototype lab



© Telefonaktiebolaget LM Ericsson and Centre for Business History

Contact info/About the site