5 Conclusion

Up to the moment when Vodafone presented the solution using its already existing GSM network with the extensions of ASCI, there were only two competitors in Europe: TETRA and Tetrapol, both of which have been developed to fulfill the special requirements of professional digital radio like public safety and security. The solution Vodafone presents has not the same functionality (e.g. long call setup time, limited group call, no gateway to analogue network), and there is no GSM ASCI network in the world that is used for public safety and security. TETRA and Tetrapol are used in several European countries. There are more experiences with such TETRA and Tetrapol networks whereas Vodafone only demonstrated the functionality within few cells. Nevertheless, the updating the software of Vodafone's network can take less time compared to building up a new TETRA or Tetrapol based network. Nevertheless, there is a major problem with the echeatage: What happens with the network if Vodafone goes bust? Vodafone has not satisfactorily tackled this problem yet. Taking this uncertainties of Vodafone's GSM ASCI network into account, it should only be chosen if the costs were much lower. But they are not.
TETRA and Tetrapol almost fulfill the requirements equally whereas Tetrapol is a bit behind: There are handover problems and no tactical addresses under development, but the handover problems will be solved in the upcoming Tetrapol standard Tetrapol 2004.IP. Additionally, TETRA was chosen as ETSI standard, not Tetrapol's predecessor TETRA-12. Moreover, a lot of suppliers provide TETRA end user devices and base stations whereas there are very few of them for Tetrapol. Generally, this should be an advantage for TETRA, but some compatibility problems occurred that did not happen using Tetrapol. Due to the fact that there are no standards for ISI within TETRA yet, it is difficult to connect TETRA networks. The suppliers of end user devices for TETRA provide special features which are unstandardized and only useable with devices made by the same supplier (e.g. dynamic encryption by Motorola). Standardization takes time and even standards can cause problems if they are not well particularized or not well put into practice. Some countries have chosen Tetrapol instead of TETRA. However, both TETRA and Tetrapol are equally suitable. Economic considerations must make the decision.
Regarding the costs that have been calculated in (GerpottWalter04), Tetrapol is the cheapest solution - mostly because there are fewer base station needed than for TETRA.
Coming to a conclusion, Tetrapol is favorable for a digital safety and security network in Germany.

Costs