Overview
ISO 17515-1:2015 - "Intelligent transport systems (ITS) - Communications Access for Land Mobiles (CALM) - E-UTRAN - Part 1: General usage" - defines how the Evolved Universal Terrestrial Radio Access Network (E-UTRAN / LTE) can be used as an ITS access technology. The standard specifies the Communication Adaptation Layer (CAL) and the Management Adaptation Entity (MAE) for ITS station interfaces (per ISO 21218) and references ISO 25111 for session management. It adopts existing international and 3GPP practices wherever practicable to enable interoperable ITS station implementations using cellular networks.
Key topics and requirements
- Support for E-UTRAN access: Enables LTE/E-UTRAN as a CALM communication interface in an ITS station.
- Communication Adaptation Layer (CAL): Provides the IN‑SAP toward ITS-S networking and transport layers and must support UC-VCIs and Link‑ID construction as specified in ISO 21218.
- Management Adaptation Entity (MAE): Implements the MI‑SAP toward ITS station management and supports defined MI‑COMMANDs (e.g., CI state changes, connect/disconnect, UC‑VCI management) and MI‑REQUESTs for event reporting.
- CI state mapping: Maps ISO 21218 CI states (not‑existent, existent, registered, active, connected, etc.) to E‑UTRAN states (e.g., POWER_OFF, RRC_IDLE, RRC_CONNECTED) to standardize lifecycle and behavior.
- Connection procedures: Specifies when to invoke RRC connection and release procedures (see Annex A) based on CI state, I‑Parameter Connect values, and MI‑COMMANDs.
- I‑Parameter support and communication profiles: Mandates access to a set of CI I‑parameters (e.g., CommProfile, CIclass, CIaccessClass, MedType, Connect, DataRate, BlockLength, LogicalChannels) consistent with ETSI/TS 102 760‑1 and ISO 21218.
- Session establishment and termination: Follows ISO 25111 for user-controlled sessions and public network usage requirements.
Applications and who uses it
ISO 17515-1:2015 is intended for:
- ITS station implementers and embedded system developers who need to integrate LTE/E‑UTRAN as an ITS access technology.
- System integrators and OEMs in intelligent transport systems deploying cellular-based communications for traffic management, telemetry, or roadside infrastructure.
- Network operators and ITS service providers specifying access class, connection behavior and QoS-related parameters for ITS devices.
- Test laboratories and certification bodies validating CALM/E‑UTRAN conformance and interoperability.
Practical benefits include reliable, interoperable use of cellular LTE networks for ITS communications, standardized management of connection states, and a clear mapping to 3GPP RRC procedures.
Related standards
- ISO 21217: CALM architecture
- ISO 21218: Access technology support (CI definitions)
- ISO 24102‑3: ITS station management - Service access points
- ISO 25111: General requirements for using public networks (session management)
- 3GPP TS 36.331 (E‑UTRA RRC specification)
- ETSI/TS 102 760‑1 (CALM test/specification references)
Keywords: ISO 17515-1:2015, CALM, E-UTRAN, LTE, ITS station, Communication Adaptation Layer, Management Adaptation Entity, ISO 21218, ISO 25111.