The TWIN consortium was set up following a public seminar which presented the findings of the ERWIN (5650) exploratory action. ERWIN investigated potential architectures for a multimedia train communication system comprising the ground segment, several types of wireless links between a mobile and the ground, and the onboard segment.
TWIN will concentrate on the wireless segment, specifically on the radio transmission link, and will investigate the interconnection of mobile subnetworks to fixed networks through this transmission medium.
The term "mobile subnetwork" designates a mobile platform carrying users of data, voice and possibly video services communicating with the outside world through access points that are concentrated onto a single radio mobile interface node. "Fixed network" means an immobile communication network with multiple access points.
The objective of the project is to study connectionless dynamic TDMA 900 MHz band radio communication which:
- Focuses on multimedia communication capabilities; mixes control command data with passenger-oriented data; and ensures the ordered and timely communication of safety-critical and time-critical data under normal and degraded transmission capacity conditions through the definition of efficient protocols with predictable behaviour.
- Is oriented towards the services offered at the LLC layer (logical link control), the MAC layer (medium access control), manages the frame structure of the physical layer of the radio segment, and relies on an existing modulation scheme similar to the one used in GSM. TWIN will ensure that the services and interfaces will also be applicable to the forthcoming short-range microwave communication segment.
- Can be adapted to future modulation schemes with a higher throughput that can support communications for high-speed trains (ie speeds over 250 km/h). To this end a partial simulation of the physical layer will be carried out. The resulting technology will be validated through simulation programs.
TWIN will liaise with other relevant European projects, especially with the UIC (Union Internationale des Chemins de Fer) group and the Euroradio project, on user requirements and safety considerations.
The phase 1 demonstrator will consist of a load simulator and an LLC prototype implementation representing a radio mobile interface node, an analyser for this node, and a simulator representing the fixed base-station.
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