Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
ISO 29281-2:2019 — Intelligent Transport Systems — Localized Communications — Legacy System Support
Supporting DSRC Legacy Systems in ITS Localized Communications Architecture
Introduction
ISO 29281-2:2019, developed by ISO/TC 204, specifies elements for supporting legacy DSRC (Dedicated Short Range Communication) systems within the ITS localized communications architecture. This second edition replaces ISO 29281-2:2013 and incorporates Amendment 1:2014. The standard ensures backward compatibility with existing ISO 15628 DSRC applications, such as electronic toll collection (ETC), while enabling migration to the modern ITS station architecture.
Legacy DSRC systems (5.8 GHz, per EN 12253 and ARIB standards) are widely deployed for toll collection worldwide. This standard provides a migration path to integrate them with the modern ITS-G5 and LTE-V2X ecosystem.
Architecture and Legacy Support Mechanisms
The standard specifies protocols and procedures located in various ITS station layers to support legacy communication interfaces (15628 legacy CIs). Key architectural components include the FSAP communication handler, legacy CI port agent, and the 15628 kernel emulator that enables legacy DSRC applications to run within the modern ITS station environment.
| Component | Function | Protocol Layer |
|---|---|---|
| FSAP communication handler | Manages Fast Service Announcement Protocol | Facilities layer |
| Legacy CI port agent | Manages communication between legacy CI and ITS-S | Access layer |
| 15628 Kernel emulator | Emulates ISO 15628 DSRC application layer | Facilities layer |
Engineering Design Insights
Communication Scenarios and Implementation
The standard defines implementation scenarios for: standalone 15628 legacy CI operation, and 15628 legacy applications via an ITS access technology suited for localized communications. CI classes are defined for registration and service operations of legacy applications. Basic primitive application functions handle the service operation phase. The architecture supports the coexistence of legacy and modern ITS applications on the same ITS station.
Conformance and Interoperability
Annex A provides normative ASN.1 definitions for data structures. Annex B specifies the 15628 legacy CI in detail. The informative Annex C provides comprehensive service guidelines for implementing 15628 legacy services. The standard references the ITS station architecture (ISO 21217), station management (ISO 24102 series), and the Fast Networking and Transport Protocol (ISO 29281-1).
This standard specifically addresses DSRC at 5.8 GHz (European backscatter and Japanese active transceiver technologies), not IEEE 802.11 OCB at 5.9 GHz which is referred to as DSRC in some regions but uses different protocols.
FAQs
Q1: What is a 15628 legacy CI?
A: A communication interface design that supports the ISO 15628 DSRC application layer, enabling legacy DSRC applications to operate within the modern ITS station architecture.
A: A communication interface design that supports the ISO 15628 DSRC application layer, enabling legacy DSRC applications to operate within the modern ITS station architecture.
Q2: Why is legacy system support important?
A: Millions of DSRC on-board units and roadside equipment are deployed globally for toll collection and access control. This standard protects that investment while enabling evolution to cooperative ITS.
A: Millions of DSRC on-board units and roadside equipment are deployed globally for toll collection and access control. This standard protects that investment while enabling evolution to cooperative ITS.
Q3: Can legacy and modern ITS applications run simultaneously?
A: Yes, the architecture supports co-existence. The same ITS station can run legacy DSRC applications alongside modern ITS-G5 or LTE-V2X applications.
A: Yes, the architecture supports co-existence. The same ITS station can run legacy DSRC applications alongside modern ITS-G5 or LTE-V2X applications.
Q4: What frequency bands are covered?
A: The legacy DSRC systems operate at 5.8 GHz, distinct from the 5.9 GHz ITS-G5 band. Both European (CEN EN 12253) and Japanese (ARIB STD-T75/T110) technologies are covered.
A: The legacy DSRC systems operate at 5.8 GHz, distinct from the 5.9 GHz ITS-G5 band. Both European (CEN EN 12253) and Japanese (ARIB STD-T75/T110) technologies are covered.
📥 Standard Documents Download
No download files available yet