EN 12795:2003

This European Standard: - defines the Data Link Layer of DSRC; - is positioned with respect to other related standards by the layers defined in OSI Basic Reference Model [EN ISO/IEC 7498-1] as adopted for DSRC; - supports broadcast and half-duplex transmission modes; - supports a variety of fixed equipment configurations. It supports configurations where one fixed equipment communicates with one mobile equipment unit, as well as configurations where one fixed equipment can communicate with several mobile equipment units; - takes into account that the mobile equipment communicates with the fixed equipment while passing through a limited communication zone; - defines neither any specific configuration nor the layout of the communication zone; - does not define to what extent different instances of fixed equipment, operating in the vicinity of each other, need to be synchronised with each other; - defines parameters to be used in negotiation procedures taking place between fixed equipment and mobile equipment. By defining two distinct sublayers, namely the medium access control sublayer and the logical link control sublayer, this standard defines: a) medium access control procedures for the shared physical medium; b) addressing rules and conventions; c) data flow control procedures; d) acknowledgement procedures; e) error control procedures; f) services provided to application layer. The MAC sublayer is specific to the DSRC. The LLC services offered are unacknowledged and acknowledged connectionless services based on [ISO/IEC 8802-2].