Overview
ISO/IEC 21228:2019 defines a coexistence mechanism for broadband powerline communication (PLC) technologies. The standard specifies a coexistence protocol (CP) that enables multiple, non‑interoperable high‑speed PLC systems to share the same powerline medium without causing harmful interference. It extends existing inter-system protocols to accommodate another in‑home system while preserving backward compatibility with IEEE Std 1901 ISP behavior.
Key topics and technical requirements
- Coexistence protocol (CP): Shares time‑domain and frequency‑domain resources between different broadband PLC systems. The CP is largely aligned with the IEEE 1901 inter‑system protocol (ISP) and ITU‑T G.9972 coexistence concepts.
- Resource sharing methods: Two primary multiplexing strategies are used:
- Time Domain Multiplex (TDM) - extended TDM resource allocation to support up to four non‑interoperable systems on the same powerline.
- Frequency Domain Multiplex (FDM) - alternative method for splitting spectral resources among systems.
- Extended TDM schemes:
- Utilizing TDM resources of an absent in‑home system (IH-A assumes the allocation of the first absent system in a fixed order IH‑W, IH‑O, IH‑G).
- Utilizing TDM resources of an access system when no access or absent in‑home systems exist.
- Compatibility and detection rules:
- IH‑A transmits ISP signals with a different periodicity (8×T) versus standard systems (4×T) so it can detect newly connected systems and relinquish resources accordingly.
- IH‑A uses phase vectors corresponding to the first absent in‑home system as specified in IEEE 1901 tables for synchronization.
Applications and practical value
- Prevents harmful interference in environments where multiple broadband PLC standards coexist (e.g., mixed deployments of IEEE 1901, ITU‑T G.hn, ISO/IEC 12139‑1).
- Enables reliable home networking and in‑premises broadband services over existing powerline infrastructure when devices from different standards operate nearby.
- Useful for system designers and implementers who need to ensure interoperability at the coexistence layer without changing underlying PHY/MAC implementations.
Who should use this standard
- PLC equipment manufacturers implementing multi‑standard coexistence.
- Network architects and integrators deploying in‑home or access PLC solutions.
- Standards developers and test laboratories validating coexistence behavior.
- Regulators and certification bodies assessing coexistence mitigation in shared powerline environments.
Related standards
- IEEE Std 1901-2010 (ISP and TDM/FDM coexistence)
- ISO/IEC 12139‑1 (High‑speed PLC MAC/PHY)
- ITU‑T G.9960 / G.9961 (G.hn family)
- ITU‑T G.9972:2010 (Coexistence mechanism for wireline home networking)
Keywords: ISO/IEC 21228:2019, coexistence mechanism, broadband powerline communication, PLC coexistence, time domain multiplex, frequency domain multiplex, IEEE 1901, G.hn, ISP, CP.