Wideband versus narrowband
A tough competitor in the Paris trials was Alcatel/SEL with the CD900 system, developed in Stuttgart. This was a solution based on high data transfer rates and great bandwidth, “a very good solution” in Maseng’s opinion. “That’s why there was such a lot of discussion of wideband versus narrowband. Elab’s solution could handle both but our Viterbi modem had problems coping with too high a data transfer rate. But that problem was only due to the hardware we were using; in principle our solution could handle any data transfer rate.”
For Alcatel/SEL, with its powerful political support, the Paris results were of course a dramatic setback. Beijer says: “Their systems were technologically very competent but they never asked, for instance, what economic outcome a system would have for the operators.”
For one thing, wideband TDMA was more suitable for large cities but uneconomical for use in sparsely populated areas. Here there was a clear demarcation line between the Nordic countries and the others. In Scandinavia coverage for the entire population was taken for granted, while in France and German it was not a high priority.
"ONLY FOR LARGE CITIES"
Thomas Haug describes taking part in the meetings of a group called GAP (Groupe d’Analyse et de Prévision), a working group established in the EEC to make forecasts about the development of telecommunications. “Some of the participants from the commercial side of the French telecom agency obviously regarded mobile telephony as an urban phenomenon. All that was needed was a system that covered the large cities. They did not discuss the technical details but that was obviously the attitude that colored their approach to the wideband issue.”
“So of course the opinions expressed by the Nordic participants were not welcome, nor the approach of Klaus Spindler, for instance, my German GSM colleague, who was also at the meetings. There are a lot of large cities in Germany and France – but large areas of both countries are sparsely populated as well.”
The wideband concept also caused problems in allocating frequencies. The maximum bandwidth available was 2 x 25 MHz and in many countries 2 x 10 MHz was already occupied by analog systems such as NMT 900 and TACS.
Beijer recalls: “That left 2 x 15 MHz at the most for GSM. The Franco-German wideband candidates had a minimum allocation granularity of 2 x 6 MHz, which could be trimmed to 2 x 5 MHz. So there were only three allocation modules to play with. Limitations like those give you no reasonable chance of being able to cope with migration from analog systems to GSM and at the same time manage spectrum allocations for new operators.”
The Danes proposed not allowing the granularity of spectrum allocations to exceed 1 MHz. This was not accepted, however, “even though a lot of people probably understood that it would be a reasonable policy. Personally speaking, I believe that several of the members of the Franco-German GSM group had already realized during discussions before the Paris trials that they were on the losing side,” Beijer says.
Author: Svenolof Karlsson & Anders Lugn
"Maybe we won because we could play more than the others," Says Torleiv Maseng, test winner in Paris.