5.6 Creation / Modification of a Channel (NewChannelReq,

1. NewChannelAns, DlChannelReq, DlChannelAns)

19

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The authors reserve the right to change specifications without notice.

LoRaWAN Specification

1. The NewChannelReq command can be used to either modify the parameters of an existing
2. bidirectional channel or to create a new one. The command sets the center frequency of the
3. new channel and the range of uplink data rates usable on this channel:

4

5 The channel index (ChIndex) is the index of the channel being created or modified.

1. Depending on the region and frequency band used, the LoRaWAN specification imposes
2. default channels which must be common to all devices and cannot be modified by the
3. NewChannelReq command (cf. Chapter 6). If the number of default channels is**N, the
4. default channels go from 0 to N-1, and the acceptable range for ChIndex is N to 15. A
5. device must be able to handle at least 16 different channel definitions. In certain region the
6. device may have to store more than 16 channel definitions.

12

1. The frequency (Freq) field is a 24 bits unsigned integer. The actual channel frequency in Hz
2. is 100 x Freq whereby values representing frequencies below 100 MHz are reserved for
3. future use. This allows setting the frequency of a channel anywhere between 100 MHz to
4. 1.67 GHz in 100 Hz steps. A Freq value of 0 disables the channel. The end-device has to
5. check that the frequency is actually allowed by its radio hardware and return an error
6. otherwise.

19

1. The data-rate range (DrRange) field specifies the uplink data-rate range allowed for this
2. channel. The field is split in two 4-bit indexes:

22

1. Following the convention defined in Section 5.2 the minimum data rate (MinDR) subfield
2. designate the lowest uplink data rate allowed on this channel. For example 0 designates
3. DR0 / 125 kHz. Similarly, the maximum data rate (MaxDR) designates the highest uplink
4. data rate. For example, DrRange = 0x77 means that only 50 kbps GFSK is allowed on a
5. channel and DrRange = 0x50 means that DR0 / 125 kHz to DR5 / 125 kHz are supported.

28 The newly defined or modified channel is enabled and can immediately be used for

1. communication. The RX1 downlink frequency is set equal to the uplink frequency.
2. The end-device acknowledges the reception of a NewChannelReq by sending back a

34 The status (Status) bits have the following meaning:

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The authors reserve the right to change specifications without notice.

1. If either of those 2 bits equals 0, the command did not succeed and the new channel has not
2. been created.

4

5 The DlChannelReq command allows the network to associate a different downlink 6 frequency to the RX1 slot. This command is applicable for all the geographic regions

1. supporting the NewChannelReq command (for example EU and China, but not for US or
2. Australia as described in the LoRaWAN Regional Parameters document [PARAMS]).
3. The command sets the center frequency used for the downlink RX1 slot, as follows:

10

11

1. The channel index (ChIndex) is the index of the channel whose downlink frequency is
2. modified
3. The frequency (Freq) field is a 24 bits unsigned integer. The actual downlink frequency in Hz
4. is 100 x Freq whereby values representing frequencies below 100 MHz are reserved for
5. future use. The end-device has to check that the frequency is actually allowed by its radio
6. hardware and return an error otherwise.

18 The end-device acknowledges the reception of a DlChannelReq by sending back a

1. DlChannelAns command. The DlChannelAns command shall be added in the FOpt field of
2. all uplinks until a downlink packet is received by the end-device. This guarantees that even
3. in presence of uplink packet loss, the network is always aware of the downlink frequencies
4. used by the end-device.
5. The payload of this message contains the following information:

24

25 The status (Status) bits have the following meaning:

©2016 LoRa™ Alliance Page 29 of 70

The authors reserve the right to change specifications without notice.

LoRaWAN Specification

1 Table 10: DlChannelAns status bits signification

2