scope:

Recommendation ITU-T G.9903 contains the physical layer (PHY) and data link layer (DLL) specification for the G3-PLC narrowband orthogonal frequency division multiplexing (OFDM) power line communication transceivers, for communications via alternating current and direct current electric power lines over frequencies below 500 kHz. This Recommendation supports indoor and outdoor communications over low-voltage lines, medium-voltage lines, through transformer low-voltage to medium-voltage and through transformer medium-voltage to low-voltage power lines in both urban and long-distance rural communications. This Recommendation addresses grid to utility meter applications, advanced metering infrastructure (AMI), and other "Smart Grid" applications such as the charging of electric vehicles, home automation, and home area networking (HAN) communications scenarios.

This Recommendation supports coexistence with other narrowband PLC technologies via frequency division and via the preamble-based coexistence mechanism specified in clause 10 of [IEEE 1901.2].

This Recommendation does not contain the control parameters that determine spectral content, power spectral density (PSD) mask requirements and the set of tools and procedures to support the reduction and measurement of the transmit PSD; all of which are detailed in Recommendation [ITU-T G.9901].

Amendment 1 covers Cenelec A, Cenelec B, ARIB and FCC bandplans. It adds the G3-PLC Hybrid PLC & RF Profile as new Annex H.

Amendment 1 also includes:

- A correction and clarification about MAC sequence number management to avoid duplicate frames also needed for the good implementation of the hybrid profile.

- The addition of phase differential information in the Path-Discovery messages, allowing for the determination of the phase connection for all devices in the path directly.

- Test vectors for cryptographic building blocks specific to the G3-PLC Hybrid PLC & RF Profile (Appendix III).

Corrigendum 1 includes:

- Corrections and clarifications to better define the Cenelec B bandplan.

- Corrections and clarifications related to the POS table and neighbour table entry creation and update rules.

- Corrections and clarifications on preamble length.

- Corrections and clarifications on the processing of reserved bits.

- Corrections and clarifications to warn implementers and end-users on the issues with the setting of some attribute which value shall be consistent throughout the PAN and be chosen within a certain range for good operation of the network.

- Corrections and clarifications of the routing protocol, including transmission of unicast RREQs, RERR error codes and related behaviour, consideration of the destination address set in unicast packet routing, avoidance of duplicate forwarding of RREQ messages and duplicate generation of RREP messages.

- Corrections and clarifications on the behaviour when the broadcast log table is full.

- Corrections and clarifications related to EIFS definition.

- Corrections and clarifications on CSMA channel access failures which shall not reset the TMR TTL timer.

- Corrections and clarifications to allow UDP checksum eliding.

- Corrections and clarifications on filtering rules of LowPAN bootstrap protocol messages prior to being processed.

- Corrections and clarifications on the rekeying feature in the hybrid profile.

- Corrections and clarifications on blacklist removal conditions in the hybrid profile.

- Corrections and clarifications on hybrid profile enhanced acknowledgement generation rules.

- Corrections and clarifications on the definition of RF weak links.

- Corrections and clarifications on FCH ACK and NACK frame formats.

- Corrections and clarifications on Information Elements extensions to ensure backwards compatibility.

- Corrections and clarifications to remove unsused macNackCount.

- Corrections and clarifications to change macAckWaitDuration into a constant.

- Corrections and clarifications to add a PhaseDifferential parameter to the MCPSDATA. indication primitive.

- Corrections and clarifications regarding the rekeying procedure including error handling.

- Corrections and clarifications fixing data rate computation inconsistencies.

- Corrections and clarifications on Information Element endianness.

Amendment 2 covers Cenelec A, Cenelec B, ARIB and FCC bandplans. It adds new mechanisms to improve efficiency of broadcast transmissions (for both data traffic and LOADng RREQ routing messages) and extends the G3-PLC Hybrid PLC & RF Profile with new operating frequency bands, an RF transmit power adaptation mechanism, frequency hopping and a last gasp feature (consisting in an alerting mechanism in case a power outage is experienced by a device in the network). FCC sub-banding is also added as a new feature.

Amendment 2 also includes several additional improvements:

- Increase of the possible number of MAC frame transmission retries.

- Reset of the tone-map to a value where all tones are active in case of fallback to ROBO modulation (in general after a transmission failure).

- New default values and valid value ranges for different attributes.

- Routing table entry TTL refresh in case of transmission over the hybrid profile backup medium.

- Possibility to export the EAP-PSK Master Session Key to upper layers.

- Addition of an attribute to disable the PLC lower layers.

- Periodic probing feature to perform channel estimation over both PLC and RF media.

- Behaviour of the protocol stack using specific out-of-range values of attributes for debugging purposes (Appendix IV) .

- Last gasp feature implementation guidelines and application layer considerations (Appendix V).