ARMmbed
/
mbed-os
mirror of https://github.com/ARMmbed/mbed-os.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Copy edit FSB_Usage.txt 

Copy edit for active voice, consistent tense and precise language.
pull/7806/head
Amanda Butler 2018-08-27 10:06:21 -05:00 committed by GitHub
parent 5cca2f2e76
commit a779e6f3c2
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 29 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
features/lorawan/FSB_Usage.txt
View File

@ -1,52 +1,52 @@
Frequency sub-bands in US915/AU915:
US915/AU915 PHYs define channel structures which can support up-to 72 channels for upstream.
First 64 channels (0-63), occupy 125 kHz and the last 8 channels (64-71) occupy 500 kHz.
US915/AU915 PHYs define channel structures that can support up to 72 channels for upstream.
The first 64 channels (0-63), occupy 125 kHz and the last 8 channels (64-71) occupy 500 kHz.
However, most of the base stations available in the market support 8 or 16 channels.
Network acquisition can become costly if the device have no prior knowledge of active channel plan and it enables
Network acquisition can become costly if the device has no prior knowledge of the active channel plan and it enables
all 72 channels to begin with.
LoRaWAN 1.0.2 Regional parameters specification refers to a strategy of probing a set of nine channels (8 + 1) for
joining process. According to that strategy the device is supposed to alternatively select a channel from a set of
8, 125 kHz channels and a 500 kHz channel.
For example send a join request alternatively on a randomly selected channel from a set of 0-7 channels and
channel 64 which is the first 500 kHz channel.
The LoRaWAN 1.0.2 Regional parameters specification refers to a strategy of probing a set of nine channels (8 + 1) for
the joining process. According to that strategy, the device alternatively selects a channel from a set of
8 125 kHz channels and a 500 kHz channel.
For example, send a join request alternatively on a randomly selected channel from a set of 0-7 channels and
channel 64, which is the first 500 kHz channel.
Once the device has joined the network (in case of OTAA) or have sent the first uplink (in case of ABP), the network
may send a LinkAdrReq mac command to set the channel mask to be used. Please note that these PHY layers do not
support CFList so LinkAdrReq is the way the network tells you what channel plan to use.
Once the device has joined the network (in case of OTAA) or has sent the first uplink (in the case of ABP), the network
may send a LinkAdrReq MAC command to set the channel mask to be used. Please note that these PHY layers do not
support CFList, so LinkAdrReq is the way the network tells you what channel plan to use.
Mbed LoRaWAN stack can be configured to use a particular frequency sub-band (FSB) which means that we don't have to
probe all sets of channels. "fsb-mask" in lorawan/mbed_lib.json is the parameter which can be used to tell the
system which FSB or a set of FSBs to use. By default the "fsb-mask" is set to "{0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0x00FF}"
that means all channels are active, i.e., 64 125 kHz channels and 8 500 kHz channels are active. If the user wishes
to use a custom FSB, he/she needs to set appropriate mask as the value of "fsb-mask". For example:
If the user wishes to use the first FSB, i.e., first 8 125 kHz channels (0-7) and the first 500 kHz channel:
You can configure the Mbed LoRaWAN stack to use a particular frequency sub-band (FSB), which means that you don't have to
probe all sets of channels. "fsb-mask" in lorawan/mbed_lib.json is the parameter that you can use to tell the
system which FSB or set of FSBs to use. By default, the "fsb-mask" is set to "{0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0x00FF}".
That means all channels are active. In other words, 64 125 kHz channels and 8 500 kHz channels are active. If you wish
to use a custom FSB, you need to set an appropriate mask as the value of "fsb-mask". For example, if you wish to use the
first FSB, in other words, the first 8 125 kHz channels (0-7) and the first 500 kHz channel:
"fsb-mask" = "{0x00FF, 0x0000, 0x0000, 0x0000, 0x0001}"
Similarly, if the user wishes to use second FSB, i.e., 2nd set of 8 125 kHz channels (8-15) and the 2nd 500 kHz
Similarly, if you wish to use the second FSB, in other words, the second set of 8 125 kHz channels (8-15) and the 2nd 500 kHz
channel:
"fsb-mask" = "{0xFF00, 0x0000, 0x0000, 0x0000, 0x0002}"
You can also combine FSBs if your base station supports more than 8 channels. For example:
"fsb-mask" = "{0x00FF, 0x0000, 0x0000, 0xFF00, 0x0081}"
will mean use channels 0-7(125 kHz) + channel 64 (500 KHz) and channels 56-63 (125 kHz) + channel 71 (500 kHz).
means use channels 0-7(125 kHz) + channel 64 (500 KHz) and channels 56-63 (125 kHz) + channel 71 (500 kHz).
Please note that for Certification requirements, you need to alternate between 125 kHz and 500 kHz channels and that's
why before joining you should not set a mask that enables only 500 kHz or only 125 kHz channels.
Please note that for Certification requirements, you need to alternate between 125 kHz and 500 kHz channels, so before joining,
do not set a mask that enables only 500 kHz or only 125 kHz channels.
Frequency sub-bands in CN470 PHY:
There are 96 channels in total defined in LoRaPHYCN470 class as per LoRaWAN Regional Specification. These 96 channels
The LoRaPHYCN470 class defines 96 channels in total, as per the LoRaWAN Regional Specification. These 96 channels
are 125 kHz wide each and can be subdivided into 6 sub-bands containing 16 channels each.
"fsb-mask-china" is the parameter defined in lorawan/mbed_lib.json which can be used to enforce an FSB. It is defined
as a c-style array and the first element of the array corresponds to first 8 channels (0-7) and so on. By default all
96 channels are enabled but there may be base stations who do not support all 96 channels and hence network acquisition
"fsb-mask-china" is the parameter that lorawan/mbed_lib.json defines. It can be used to enforce an FSB. It is defined
as a C-style array, and the first element of the array corresponds to first 8 channels (0-7) and so on. By default, all
96 channels are enabled, but there may be base stations that do not support all 96 channels. Therefore, network acquisition
can become cumbersome if the device hops on random channels. The probability of finding a correct channel for a base station
who support 8 channels would be 1/12.
that supports 8 channels would be 1/12.
For example, say your base station supports 16 channels (channels 0-15), you would set the "fsb-mask-china" as:
For example, if your base station supports 16 channels (channels 0-15), set the "fsb-mask-china" as:
"fsb-mask-china" = "{0xFFFF, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}"
Yet another example, say your base station supports 8 channels (channels 0-7), you would set the "fsb-mask-china" as:
Similarly, if your base station supports 8 channels (channels 0-7), set the "fsb-mask-china" as:
"fsb-mask-china" = "{0x00FF, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}"