Overview
ISO 22738:2020 - Intelligent transport systems - Localized communications - Optical camera communication - specifies Optical Camera Communication (OCC) as an access technology for localized communications in Intelligent Transport Systems (ITS). The standard defines the ITS‑OCC communication interface (CI) and the adaptations required to make IEEE 802.15.7:2018 OCC functionality compatible with ITS station and hybrid communications architectures (ISO 21217 and ISO 21218). ISO 22738:2020 covers physical (PHY) and medium access control (MAC) aspects, management entities, conformance and test methods, plus normative annexes (parameters, MI‑COMMAND/REQUESTs, ASN.1 definitions).
Key topics and technical requirements
- ITS‑OCC CI and profile: Defines an OCC profile of IEEE 802.15.7 tailored for Cooperative ITS (C‑ITS) and localized communications.
- PHY & MAC architecture: Maps IEEE 802.15.7 PHY/MAC to the ITS station access layer; requires support for PHY mode IV (intended for discrete light sources).
- Modulation & link considerations: Addresses modulation schemes and MAC frame formats; abbreviations in the standard include OOK, M‑FSK, PSK variants, VPPM/VPWM and rolling‑shutter methods.
- Dimming and flicker mitigation: Specifies dimming methods and measures to mitigate perceptible flicker in vehicle and roadside LED signaling (see Annex F).
- Management and adaptation: Details Communication Adaptation Layer (CAL) and Management Adaptation Entity (MAE) requirements per ISO 21218 and ISO 24102‑3.
- Interoperability & conformance: Adds/deviates from IEEE 802.15.7 to ensure compatibility with ITS station architectures; includes conformance clauses and test methods (Annexes and normative references).
- Safety note: Recognizes limitations - OCC links can be interrupted or blocked due to shadowing, which is important for safety‑related services.
Practical applications and users
- Use cases
- Broadcast of ITS messages from traffic lights, street lights and traffic signs to vehicles (one‑to‑many).
- Vehicle‑to‑vehicle and vehicle‑to‑roadside information exchange using LED transmitters and camera receivers (visible or near‑IR).
- C‑ITS, urban ITS (U‑ITS), and ADAS applications that augment RF communications with optical localized links.
- Who should use this standard
- Vehicle OEMs and Tier‑1 suppliers integrating OCC transmitters/receivers.
- ITS infrastructure manufacturers (traffic lights, signage, street lighting).
- System integrators, test laboratories and compliance engineers.
- Standards implementers and researchers working on hybrid communications for ITS.
Related standards
- IEEE 802.15.7:2018 (Optical Wireless Communication - basis for OCC)
- ISO 21217 (ITS station & communications architecture)
- ISO 21218 (Hybrid communications - access technology support)
- ISO 24102‑3, ISO 17419, ISO/IEC 8825‑2 (referenced for MAE, IDs and ASN.1 encoding)
ISO 22738:2020 is essential for deploying OCC in ITS ecosystems - enabling camera/LED based localized communications that complement radio solutions while clarifying interoperability, management and test requirements.