This International Standard determines the air interface options applicable to CALM using third generation (3G) cellular networks. In particular, this International Standard specifies protocols and parameters that 3G systems shall include to support prolonged, long-range, high data rate wireless communication links in ITS environments where heterogeneous handovers or media independent handovers (MIH) are either necessary to maintain the link, or desirable, as determined by media selection policies. This International Standard provides protocols and parameters for long range, medium speed wireless communications in the ITS sector using third generation cellular communications. Wherever practicable, this International Standard has been developed by reference to suitable extant Standards, adopted by selection. Required regional variations are provided. Specifically, for this International Standard, extant 3G systems, as defined by various international and national Standards, are adopted by reference. Application specific upper layers are not included in this Standard, but will be driven by application standards (which may not be technology specific).