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144 From smart grid to internet of energy

TABLE 4.5 Some characteristics of the ITU G.9903 G3-PLC standard

Frequency ARIB (from 154.7 to 403.1 kHz)
bands
FCC-1 (from 154.6875 to 487.5 kHz)
FCC-1.a (from 154.6875 to 262.5 kHz)
FCC-1.b (from 304.687 to 487.5 kHz)
CENELEC A (from 35.938 to 90.625 kHz)
Mapping DBPSK, DQPSK, or D8PSK mapping scheme based OFDM (BPSK,
scheme QPSK, 8-PSK or 16-QAM may be optionally utilized)
Data rate Maximum 300 Kbps
Data link layer IEEE 802.15.4 based MAC sublayer and IETF RFC 4944 based
adaptation sublayer
Channel CSMA/CA with a random back-off time
access
Convergence IPv6 6LoWPAN
layer
Security EAP-PSK, AES-128 key and CCM encryption

4.4.2.1 PHY layer
ITU G.9903 standard based systems can be arranged to support the FCC, CEN-
ELEC, ARIB bands in the frequency range between 10 and 490 kHz. Several
PHY parameters of this standard for these bands are listed in the Table 4.6.Even
though the differential modulation schemes are specified in the G3-PLC, differ-
ential encoding is preferred in the time direction. In addition, 16-ary QAM
scheme can be optionally employed in the standard. The FEC of the standard
is based on the combination of convolutional codes (CC) with ½ rate and RS
code with (255,239) code length. Either four-times or six-times repetition is also
exploited in robust transmission mode (called ROBO mode). Data rates of PHY
layer may typically change from 4 to 200 Kbps [82].
The block diagram of PHY layer transmitter is illustrated in Fig. 4.7. The
standard has three different operation modes that are called normal, robust
and super robust modes. The super robust mode is defined for extremely
destructive channel environments. As mentioned before, the two-dimensional
interleaver is employed to protect systems against burst errors that may be
occurred by time and frequency dependent noises. Different modulation
schemes and optional coherent modulation techniques such as BPSK, QPSK,
8PSK and 16QAM can be selected as mapping method in this standard. In addi-
tion, there is an opportunity to deactivate subcarriers with low SNR for improv-
ing total transmission reliability.