Issue link: https://read.uberflip.com/i/1428395
LoRaWAN ® L2 1.0.4 Specification © 2020 LoRa Alliance ® Page 30 of 90 The authors reserve the right to change specifications without notice. Size (octets) 1 2 1 LinkADRReq payload DataRate_TXPower ChMask Redundancy Table 17: LinkADRReq payload format 913 914 915 916 Bits [7:4] [3:0] DataRate_TXPower DataRate TXPower Table 18: DataRate_TXPower field format 917 918 919 The requested date rate (DataRate) and TX output power (TXPower) are region-specific 920 and encoded as indicated in the "LoRaWAN Regional Parameters" [RP002] document. The 921 TX output power indicated in the command is to be considered the maximum TX power at 922 which the end-device may operate. An end-device SHALL acknowledge the successful 923 receipt of a command that specifies a higher TX power than it is capable of using. In that case, 924 the end-device SHALL operate at its maximum possible power. An end-device will negatively 925 acknowledge a command that specifies a lower TX power than the end-device is capable of 926 using. In that case, the end-device SHALL operate at its previously configured TX power. The 927 value 0xF (decimal 15) of either DataRate or TXPower means that the end-device SHALL 928 ignore that field and keep the current parameter values. An end-device SHALL support a 929 minimum power control range, such that it can operate from its maximum TX power down to 930 the max (2dBm, maximum TX power – 14dB). It is RECOMMENDED that an end-device 931 supports a minimum TX power of +2dBm. 932 933 Note: In case of good RF conditions, the Network should slowly lower 934 an end-device's TX power and/or raise the end-device's data rate to 935 avoid making drastic changes that may strand the end-device. 936 937 The channel mask (ChMask) SHALL encode the channels usable for uplink access as follows 938 with bit 0 corresponding to the LSB: 939 940 Bits Usable channels 0 Channel 1 1 Channel 2 .. .. 15 Channel 16 Table 19: Channel mask format 941 942 943 If a bit in the ChMask field is set to 1, the corresponding channel SHOULD be used for uplink 944 transmissions if this channel allows the data rate currently used by the end-device. A bit set 945 to 0 means that the corresponding channel SHALL NOT be used. 946 947 Bits 7 [6:4] [3:0] Redundancy RFU ChMaskCntl NbTrans Table 20: Redundancy field format 948