The development of intelligent transport systems (ITS) generates an increasing demand for data exchanges between different types of sensors, transport users and the data centres responsible for collecting, analysing and processing data and then disseminating this data to transport service users. Furthermore, there is an increasingly urgent need for access to relevant real-time information and for interaction between users and vehicles and their immediate environment, notably to ensure transport safety.
These exchanges are now possible thanks to the availability of broadband communications systems and networks which are accessible almost anywhere, anytime. They will be even more widely available in the future with new communication technologies allowing interaction between vehicles and between vehicles and the transport infrastructure.
The communication systems currently used for ITS, present the following characteristics:
- conventional means of transmission by telephone cables or fibre optics are used to connect sensors installed in the transport infrastructure (for example, electromagnetic loops or cameras). Where this is not possible, the cost of laying cables can be very high and it may therefore be better to replace them with wireless means of transmission with connections either to the mobile telephone network (General Packet Radio Service (GPRS): the data transmission standard for second generation mobile phone networks (http://www.3gpp.org/-technologies-)]] or 3G  contracts with an operator) which itself is connected to the internet network making it possible to exchange with traffic data centres, or to private radio transmitters.
- Depending on the wireless transmission technology required, dedicated radio waves can offer short-range links of up to approximately 1000 m (radio solutions using license-exempt bandwidths at 433 MHz, 870 MHz, 2.4 GHz or 5.4GHz) or longer range links of up to 10 km (licensed radio-relay systems or WiFi links  license-exempt directives at 5.4 GHz).
- The operators of transport infrastructures are generally equipped with a dedicated radio network for communicating with their personnel, notably when engaged in emergency response (using ) - in France, the 40 MHz band is reserved for the national highways agency). These networks can be used for automatic data exchange with traffic management centres. The marketing of digital technologies such as ( ) will reinforce the effectiveness of data exchange services.
- Increasingly, both mobile users and their vehicles are equipped with a mobile terminal (or vehicle-integrated communications units), connected to a mobile phone network and have a contract including unlimited internet access.
- Bandwidths vary according to the means of transmission (from several kilobytes/second to several megabytes/second). These bandwidths are not usually guaranteed by telecommunications operators and often cannot be accessed at all in the event of network saturation (in crisis situations for example). This is why transport infrastructure operators prefer to use transmission solutions with guarantee bandwidth and availability to connect their equipment in the field.
- ITS communication protocols are now primarily based on Internet Protocol (IP) and ethernet, the standard protocols for IT networks and the internet.
- Communications links and their constituent components must be protected against security breaches from a variety of sources: internet, intranet, operator networks or networks in the field. This is particularly important for signalling equipment (variable message signs, barriers etc.) and their control systems, to avoid unwanted control commands, and for video surveillance systems, to avoid the uncontrolled posting of video sequences on the internet. This is also the case, to a lesser extent, for other pieces of equipment in order to avoid denial-of-service attacks.
 3G: which corresponds to the data transmission standard for third generation mobile phone networks
 Private Mobile Radiocommunications networks
 Digital Mobile Radio (ETSI standard for digital PMR systems)
Near Field Communication (NFC) technology is a specific mode of very short range (several centimetres) wireless data transmission, developed as part of a wider range of technologies - radio-frequency identification (RFID).
This technology, initially based on contactless RFID, is increasingly widely deployed on mobile telephones. NFC allows users on the move to access services such as payment, smart ticketing or data exchange via their telephone.
This technology is likely to develop rapidly in the short term. Although the NFC frequency (13.56 MHz) is not the same as the Bluetooth (2.4 GHz) and WiFi (2.4 GHz and 5 GHz) frequencies, chip manufacturers have innovated and offered mobile phone manufacturers a reliable solution to allow Bluetooth, WiFi and NFC applications to be used on the same device.
The principle is simple: Two devices can communicate by simply being brought into close proximity. This instantly triggers a wireless interface which automatically configures a network connection.
The operating distance is between 0 - 20 centimetres. The interest of this very short distance is to secure NFC data exchange as the connection is broken as soon as the devices are no longer in contact.
There are two NFC operating modes:
- Active mode: The two devices generate a radio field to create a connection,
- Passive mode: Only the initiating device generates a radio field and the passive chipset uses the initiating device’s energy to transmit data. In passive mode the chipset does not need a power supply, which simplifies its installation in all types of systems.
The risks related to NFC use are mainly due to the device used: Mobile telephones. Like computers, when they connect to the internet these devices are exposed to attacks from viruses, worms or Trojan horses.
What are the possible applications of NFC?
NFC technology forms the basis for new mobile services, for example contactless mobile payment applications.
Other possible uses include authentication, with NFC mobile telephones acting as a key or badge to access restricted areas.
In the transport sector, NFC can be used to facilitate numerous operations. At the last International Motor Show, Orange and Valeo presented a car sharing solution using NFC technology. This solution makes it possible to securely transfer a key by mobile telephone so the user can access (open/start up) a pre-ordered vehicle.
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The wealth of possibilities for ITS development have lead international standardisation bodies (ISO/IEC, ETSI) to define a communication architecture for ITS  and to specify communications protocols to facilitate data exchanges between the different stations (fixed or mobile) that make up intelligent transport systems. These standards will structure the future of technological developments for future ITS communications systems.
Under this architecture, communications centres (traffic data centres, infrastructure sensors, users, vehicles) can be permanently connected to the ITS system via several simultaneous links established using different means of transmission: Ethernet type links using cables, radio links at 2.4 GHz (WiFi, Bluetooth ) at 5.4 GHz (WiFi), at 5.8 GHz ( ), at 60 GHz, infra-red links, links to mobile telephone networks (2G, 3G, 4G).
 Dedicated Short Range Communications (DSRC): Standardised short-range radio transmission technology for the road transport sector, mainly used for electronic toll collection (http://www.etsi.org/website/Technol...)
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More information can be found on the MEDDTL Skills and Innovation Cluster on Satellite Applications and Telecommunications website
Two other websites may be of interest:
- The ETSI website (European Telecommunications Standards Institute) on intelligent transport systems
- The ISO website on the communications access for land mobiles concept