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288 From smart grid to internet of energy

FIG. 7.9 Comparison of LPWAN, cellular and IEEE 802.15.4 technologies.

cities, industrial monitoring and metering applications. The improvement of
LoRa is being maintained in two essential layers with particular techniques that
Chirp Spread Spectrum (CSS) modulation technique for PHY and LoRaWAN
protocol for MAC layer. In its current state, minimum transmission bandwidth
of LoRa is 125 kHz and that supports 157 dB coupling loss at its maximum. The
CSS is being improved to increase immunity to interference [54, 55].
The key features and comparisons of leading LPWAN technologies; LoRa,
Sigfox, LTE-M, and NB-IoT, have been listed in Table 7.3. Sigfox UNB is
another emerging technology supporting low-power end devices used in smart
meters and home appliances. It provides a cellular technology approach oper-
ating in sub-GHz band with Binary Phase Shift Keying (BPSK) and differential
BPSK (D-BPSK) modulations at 868 and 902 MHz frequencies. Sigfox pro-
vides up to 400 channels by dividing the frequency spectrum into 100 Hz,
and coverage area is extended up to 10 km in urban area while it reaches up
to 50 km in rural areas. Besides LoRa and Sigfox that both operate in unlicensed
spectrums and sub-GHz, 3GPP has started IoT MTC study in 2009. The first
user equipment (UE) of IoT technology has been introduced by 3GPP as
LTE-M in Release 12. The proposed technology is later defined as NB-IoT that
operates 200 kHz carrier in Release 13. NB-IoT uses OFDMA modulation for
downlink, single-carrier frequency division multiple-access (SC-FDMA) for
uplink, rate matching, interleaving, and enhanced channel coding methods.
Despite of LTE-M, NB-IoT only supports tail-biting convolution coding in
the downlink, eliminating turbo-decoding requirement at the UE [54, 55].
The IoE infrastructure associating IoT and smart grid demands is shown in
Fig. 7.10. The applications include smart home automation system based on