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Power line communication technologies in smart grids Chapter 4 147

FIG. 4.8 Priority contention windows in ITU-T Rec. G.9903 (G3-PLC). (From Narrowband
orthogonal frequency division multiplexing power line communication transceivers for G3-PLC net-
works, ITU-T Rec. G.9903, August 2017. [Online] Available: http://www.itu.int/rec/T-REC-G.9903
(Fig. 9-4), with permission.)

addition, the packet originator looks forward to a certain time (macAckWait-
Duration) for the reception of an acknowledgement. In the lack of an acknowl-
edgement or the reception of an NACK, it is assumed that the transmission was
unsuccessful and retransmission process is performed in the appropriate conten-
tion period. The “macMaxFrameRetries” MAC parameter defines the maxi-
mum number of retransmissions.
Security and data protection structure of the G3-PLC is developed according
to the MAC security suite of IEEE 802.15.4 clause 7.6 that employs an encryp-
tion mechanism depending symmetric keys ensured by higher layers. All nodes
of a Personal Area Network (PAN) distributes a group master key (GMK) that is
employed to encrypt all MAC data messages in the event of security activated.
The GMK is shared with all nodes during the bootstrap process.

4.4.2.3 Adaptation layer
In the ITU G.9903 G3-PLC Standard, the 6LoWPAN has been selected to adapt
IPv6 into the PLC. It also combines the layer 2 routing, fragmentation, header
compression and security. Furthermore, it can supply a network protocol usage
for transport protocols such as TCP, UDP and ICMPv6.

4.4.3 ITU-T G.9904 PRIME standard

In 2009, PRIME (PoweRline Intelligent Metering Evolution) Alliance was
founded for the purpose of improving and employing open and standardized
solutions for smart metering and SG applications under the leadership of Span-
ish Iberdrola [86]. The PRIME Alliance aims to develop specifications for
OFDM based NB-PLC systems operating in the CENELEC-A band. The fun-
damental application area of the PRIME is the communications among the
smart meters located in the LV power lines and the base node that is generally
located on the data concentrators established in transformer stations. In 2012,
PRIME version 1.3.6 was standardized by ITU with title of ITU-T Rec.
G.9904 (PRIME) [83].