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LoRaWAN® Regional Parameters RP002-1.0.4 ©2022 LoRa Alliance ® Page 92 of 101 The authors reserve the right to change specifications without notice. Gaussian filter BT = 1,0 DC-Free Encoding Whitening Encoding Table 105: FSK physical layer settings 1868 To avoid a non-uniform power distribution signal with the FSK modulation, a data whitening 1869 DC-free data mechanism is used as shown in the above table. 1870 4.3 LR-FHSS Description 1871 LR-FHSS modulation is only used on the uplink. 1872 4.3.1 LR-FHSS Physical Layer Description 1873 LR-FHSS is a fast frequency hopping spread spectrum (FHSS) modulation with bit rates 1874 ranging from 162bits/s to 325bits/s. 1875 When a device transmits a packet using LR-FHSS on a given channel, the packet content is 1876 modulated across several pseudo-random frequencies that spans the interval: 1877 = ± /2 1878 For FCC 47 CFR Part 15 compliance, the end-device frequency hops across 60 physical 1879 channels on a 25.4 kHz frequency grid. 1880 For ETSI based countries, the end-device frequency hops across 35 or 86 physical channels 1881 on a 3.9 kHz frequency grid. 1882 All physical channels are statistically used equally. 1883 The transmission starts on a random frequency inside the interval, and the following frequency 1884 hopping pattern is also randomly selected and announced in the LR-FHSS packet physical 1885 header. The transmission carrier frequency changes every 102.4 msec for each payload 1886 fragment, and 233.472 msec for each PHY header. 1887 The instantaneous LR-FHSS modulation bandwidth is 488 Hz. Therefore, a single LR-FHSS 1888 channel actually corresponds to many physical frequency channels. 1889 The LR-FHSS frequency hopping bandwidth is region-specific. 1890 The LR-FHSS physical layer is described in the following table: 1891 1892 LR-FHSS Frequency Hopping BW (all hops) LR- FHSS BW of a single hop Minimum Separation Between LR- FHSS Hopping Channels (grid) Number of Physical Channels Usable for Frequency Hopping Per End-Device Transmission Number of Physical Channels Available for Frequency Hopping Coding Rate Physical Bit Rate 137 kHz 488 Hz 3.9 kHz 35 280 (8x35) 1/3 162bits/s 2/3 325bits/s 336 kHz 488 Hz 3.9 kHz 86 688 (8x86) 1/3 162bits/s 2/3 325bits/s 1.523 MHz 488 Hz 25.4 kHz 60 3120 (52x60) 1/3 162bits/s 2/3 325bits/s Table 106: LR-FHSS physical layer description 1893 1894