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Communications access for land mobiles (CALM)〔http://www.isotc204wg16.org/concept〕 is an initiative by the ISO TC 204/Working Group 16 to define a set of wireless communication protocols and air interfaces for a variety of communication scenarios spanning multiple modes of communications and multiple methods of transmissions in Intelligent Transportation System (ITS). The CALM architecture is based on an IPv6 convergence layer that decouples applications from the communication infrastructure. A standardized set of air interface protocols is provided for the best use of resources available for short, medium and long-range, safety critical communications, using one or more of several media, with multipoint (mesh) transfer. Since 2007 CALM stands for Communication Access for Land Mobile, before that year, CALM stood for Communications, Air-interface, Long and Medium range. ==Communication Modes== CALM enables the following communication modes: * Vehicle-to-Infrastructure (V2I): communication initiated by either roadside or vehicle (e.g. petrol forecourt or toll booth) * Vehicle-to-Vehicle (V2V): peer to peer ad hoc networking amongst fast moving objects following the idea of MANET's/VANET's. * Infrastructure-to-Infrastructure (I2I): point-to-point connection where conventional cabling is undesirable (e.g. using lamp posts or street signs to relay signals) Methods of transmission used by CALM may be based on one or more of the following communication media: * Infrared * GSM (2G, 3G cellular telephone communication technology) * DSRC 5.8-5.9 GHz (legacy systems) * Various evolutions of the IEEE 802.11 standard including WAVE (IEEE P1609.3/D23), M5 (ISO 21215) * WiMAX, IEEE 802.16e * MM-wave (63 GHz) * Satellite * Bluetooth * RFID The CALM architecture provides an abstraction layer for vehicle applications, managing communication for multiple concurrent sessions spanning all communications modes, and all methods of transmission. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Communications, Air-interface, Long and Medium range」の詳細全文を読む スポンサード リンク
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