The objective of the new RDS-TMC service, is to broadcast Traffic and Travel Information (TTI) messages on VHF/FM broadcast transmissions using RDS. The TTI messages are digitally coded in such a way, that they are language-independent. The coding also permits receivers to filter messages to the user, allowing only those messages that are relevant to the user’s journey, to be presented.
Thus, it will be possible for a tourist or freight vehicle driver to travel from, say, London to Rome, through Belgium, Germany, Switzerland, France and Italy, obtaining all the useful traffic and travel information via RDS-TMC, in his own language. The information will be decoded using a smart card that could be acquired in London, and will contain the location codes for roads on the Trans European Road Network in each country.
But for this objective to be achieved, a large number of harmonized administrative arrangements have to be agreed among the countries concerned. Many projects are now undertaking the final implementation planning stages of the introduction of RDS-TMC. The EPISODE Project, (see associated site for more detail), funded by the European Commission, DG XIII, is working on the broadcast sector issues raised by the introduction of RDS-TMC services.
At the TMC-Now! Conference held by the EBU and the EPISODE Project on 19th and 20th March, Simon Parnall, BBC R&D gave an invited presentation on the need for protocols to permit "TMC messages" to be delivered on transmission technologies other than RDS. He accepted that RDS-TMC should go ahead and this has subsequently been further supported by a meeting of Public Broadcasters. Nevertheless it seems most timely that a new protocol is developed for the future. The Public Broadcasters agree and are in the process of establishing the most appropriate structure for a new Project Group with the suggested name of the Transport Programme Experts Group. Transport has been chosen to cover all possible modes and is used as a wide definition word.
The idea of TPEG will allow the generation of messages without the need for a "smart card" to carry location codes in a receiver and it will be designed so that various delivery technologies can carry the same message, without further compression. However low bandwidth delivery technologies, such as RDS, will be able to use Serial Adaptation Layers to compress this information to carry similar data.
TPEG will be developed over the coming months and this article should be seen as an historic reference to the work now needed. In the short to medium term, the Public Broadcasters support the TPEG activity to achieve a suitable protocol for DAB and expect many other useful proposals to come from the TPEG Project.
The TPEG presentation, in Powerpoint format, can be downloaded by clicking here.