ISO 21215:2018

Overview

ISO 21215:2018 - Intelligent transport systems - Localized communications - ITS‑M5 specifies a communication interface (CI) called ITS‑M5 for localized, short‑range vehicle communications in the 5 GHz microwave bands. ITS‑M5 is based on IEEE Std 802.11™ (wireless LAN) with defined additions and deviations to make IEEE 802.11‑based devices compatible with the ITS station and communication architecture (ISO 21217). The standard targets cooperative ITS and urban ITS use cases and describes the protocol stack, management interfaces, procedures, conformance and test methods for ITS‑M5 implementations.

Key technical topics and requirements

• IEEE 802.11 compliance with ITS-specific amendments: ITS‑M5 requires conformance to IEEE Std 802.11‑2016 with specified restrictions and extensions to operate in the ITS context (including support for OCB / 802.11p modes).
• 5 GHz localized communications: The “M5” name denotes microwave operation in the 5 GHz range (regional allocations such as 5 855–5 925 MHz are referenced via ETSI harmonized standards).
• Protocol stack: Defines PHY (OFDM-based for ITS‑M5) and MAC/LLC layers plus a communication adaptation sub‑layer to interface with ITS station services.
• MI‑SAP / IN‑SAP support: Specifies how the ITS‑M5 CI provides the IN‑SAP (ITS access) and uses the MI‑SAP and SI‑SAP service primitives defined in ISO 24102‑3 and ISO 21218.
• Hybrid communications & OCB: Supports hybrid communications architectures and operation outside the context of a BSS (OCB / 802.11p) for vehicular direct communications.
• Optional path and flow management: Supports path/flow management per ISO 24102‑6 (optional) with related MI‑COMMAND and MI‑REQUEST primitives.
• Management, procedures and conformance: Includes CI management adaptation entity, procedures (transmit/receive, MAC address handling, prioritization), normative annexes (parameters, MI commands/requests, ASN.1 definitions), and test/PICS proforma for conformance.

Practical applications and who uses this standard

• Vehicle OEMs and Tier‑1s: Integrate ITS‑M5 radios in onboard units for V2V and V2I safety messages.
• Roadside unit (RSU) manufacturers: Build infrastructure units compliant with ITS station architecture and regional radio rules.
• ITS integrators and system architects: Design hybrid ITS solutions combining ITS‑M5 with cellular and other access technologies.
• Test labs and certification bodies: Use the conformance and test method clauses and PICS proforma to evaluate implementations.
• Regulators and planners: Reference ITS‑M5 when harmonizing local 5 GHz allocations and ITS deployment policies.

Related standards

• ISO 21217 (ITS station architecture)
• ISO 21218 (Hybrid communications - access technology support)
• ISO 24102‑3 / ISO 24102‑6 (MI‑SAP, path & flow management)
• IEEE Std 802.11‑2016 (base WLAN)
• ETSI EN 302 571 / EN 301 893 (regional 5 GHz radio rules)

Keywords: ISO 21215:2018, ITS‑M5, intelligent transport systems, localized communications, IEEE 802.11, 802.11p, 5 GHz, V2V, V2I, ITS station.