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Power line communication technologies in smart grids Chapter 4 145

TABLE 4.6 PHY layer parameters of the ITU G.9903 G3-PLC standard

Parameter CENELEC A/B FCC/ARIB
Sampling frequency (kHz) 400 1200
FFT size 256 256
Subcarrier spacing (kHz) 400/256 ¼ 1.5625 1200/256 ¼ 4.6875
Number of subcarriers 36 (CENELEC A) 72 (FCC)
16 (CENELEC B) 54 (ARIB)
Guard interval (samples/μs) 30 (CENELEC A) 30 (FCC)
75 (CENELEC B) 25 (ARIB)
Cyclic prefix (samples/μs) 22 (CENELEC A) 22 (FCC)
55 (CENELEC B) 18.33 (ARIB)
FCH modulation DBPSK BPSK
Interleaver Per Reed-Solomon Per Reed-Solomon
block block
Preamble length (ms) 6.080 2.027
FCH length (symbols) of the data 13 (CENELEC A) 12 (FCC)
frames
30 (CENELEC B) 16 (ARIB)
Max payload length (symbols) 252 511
FEC FCH (data frames) Super robust mode: convolutional code (with ½
rate and 7 constraint length) + repetition coding
by 6
FEC payload Normal mode: Reed-Solomon (with 255 block
length, 239 message length and 8 correctable
symbol errors) and convolutional code (with ½
rate and 7 constraint length)
Robust mode: Reed-Solomon (with 255 block
length, 245 message length and 8 correctable
symbol errors) and convolutional code (with ½ rate
and 7 constraint length) and repetition coding by 4

4.4.2.2 MAC sublayer
The MAC layer of the G3-PLC was developed in accordance with IEEE
802.15.4-2006, and 6LoWPAN is employed to enable IPv6 in the standard.
The channel access is achieved by means of CSMA/CA mechanism with a ran-
dom back-off time. The random back-off time structure assists to decrease col-
lision probability. If a node desires to transmit data frames, it has to wait for the