**4.1 Safety**

454 Wireless Communications and Networks – Recent Advances

The Communications Access for Land Mobiles (CALM) framework is an ISO TC204 initiative that specifies a common architecture, network protocols and communication interface definitions for wired and wireless communications using various access technologies including cellular 2nd generation, cellular 3rd generation, satellite, infra-red, 5 GHz micro-wave, 60 GHz millimetre-wave, and mobile wireless broadband (CALM, 2007). These and other access technologies that can be incorporated are designed to provide broadcast, unicast and multicast communications between mobile stations, between mobile

The CALM concept is therefore developed to provide a layered solution that enables continuous or quasi continuous communications between vehicles and the infrastructure, or between vehicles, using such (multiple) wireless telecommunications media that are available in any particular location, and have the ability to migrate to a different available media where required. Media selection is at the discretion of user determined parameters.

different ITS applications have different requirements, therefore it is impossible to use a

 *Vehicle-to-Infrastructure*: Multipoint communication parameters are automatically negotiated and subsequent communication may be initiated by either roadside or

*Infrastructure-to-Infrastructure*: The communication system may also be used to link

 *Vehicle-to-Vehicle*: A low latency peer-to-peer network with the capability to carry safety related data such as collision avoidance and other vehicle-vehicle services such as ad-

At a high level, on the one side there are multiple services possibly operating simultaneously all requesting communications services, whereas on the other side there is a possibility of multiple communications media opportunities in the vehicle to handle the transaction. In the middle CALM is located managing quasi continuous communications using the available media, to satisfy the needs of one or multiple applications. It is important

Finally, it is important to highlight that the specifications and standards of CALM are not a physical piece of equipment. While CALM may indeed operate through a "box" designed to achieve its tasks, it is actually a set of protocols, procedures and management actions. The

Together with the evolution of vehicular networks numerous novel ITS applications have emerged. Typical examples of co-operative applications include remote diagnostics,

to understand that the vehicle may be maintaining multiple simultaneous sessions.

**3.2.3 Communications Access for Land Mobiles** 

and fixed stations and between fixed stations in the ITS sector.

The motivations behind this standardization effort are the following:

different countries use different ITS media,

hoc networks linking multiple vehicles.

implementation is actually a commercial decision.

vehicle.

**4. Applications** 

single carrier to support all types of applications.

The following communication types are supported by CALM:

fixed points where traditional cabling is undesirable.

One of the main goals of transport authorities is the minimization of traffic accidents and the increase of road safety. The exploitation of wireless technologies will be a significant asset towards this direction as it has been obvious from the results of the SAFESPOT project (SAFESPOT, 2006-2010). Examples of co-operative safety related applications will be given below.
