Page 6 - May2016

PAVING THE WAY FOR DECT’S SUCCESS
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Paving the way for DECT’s success
It’s the 20th Anniversary of DECT World this year. A good time, then, for DECT Forum exec Daniel Hartnett to catch up with the "godfather of DECT", Dag Akerberg (seen on the left in the picture above, with colleagues Rupert Goddings (Ollivetti) and Günter Kleindl (Siemens)) at his home in Gothenburg.
DH: Dag, as a relatively new arrival in the world of DECT, can I ask you on behalf of all of our readers and the industry at large to cast your mind back to the very beginning of DECT. How did it come into existence and what was your role was in it?
DA: Back in the early 80s, the telephone market was totally dominated by wired telephone sets connected to the public telephone network. Ericsson, one of the world’s leading manufacturers of telephone systems, also manufactured the wired telephone. At the beginning of the 1980s, Ericsson’s customers from around the world asked for delivery of the novel, single-channel analog 47 MHz cordless phones, now emerging in Japan and the US.
At that time, I was Technical Manager of the Ericsson on-site wireless paging division,
which was tasked to study whether Ericsson should start developing cordless phones. Ericsson had had mobile radio systems for years, with analog mobile telephone systems (NMT) and wireless paging systems in production. My study concluded that Ericsson would not be able to compete with low-cost Japanese imports of these simple analog phones. But I understood that cordless phones had come to stay.
Ericsson had a healthy, large-PABX market with integrated wireless pagers. The pager was the wireless bell in the pocket. We saw that the next step would be to have the whole telephone in the pocket. But to serve 10-1000 PABX customers with cordless phones, single line analog phones would not do. You would need a sophisticated pico-cell system that at the same time was low cost and easy to plan and install.
So in 1982 I was tasked to design such a system together with a colleague, Bengt Persson. We designed an MC/TDMA/TDD (multi-channel/ time-division-multiple- access/time-division duplex) system with dynamic channel selection. This enabled very cost-effective, multi-channel base stations and handsets, and made all radio channel planning obsolete.
It was automatic. This was an absolute requirement for preserving the individual radio link quality and system capacity, in an environment of totally uncoordinated, unlicensed system installations. We patented the concept, and put it in a drawer, because the Ericsson management did not allow us to invest in it at that time.
In the mid-80s, when the UK launched their CT2 system, we brushed the dust from our TDMA/TDD concept. We called the system
DECT Today - The Success Story Continues · www.dect.org