ACDEFGHIJKLMNOPQRSTUVWXYZAA
1
Formulas taken from AN1200.13 (LoRa Modem Designers Guide)
2
http://www.semtech.com/images/datasheet/LoraDesignGuide_STD.pdf
3
No warranty of correctness!
4
Please do not request write access; instead, save a copy of this sheet to allow for changing the input values (menu File » Make a copy, or File » Download as).
5
6
Input
7
Application payload size24 bytes
For LoRaWAN: maximum around 51 for low data rates (SF12), up to about 222 bytes for best conditions (SF7).
8
LoRaWAN header size13 bytes
For LoRaWAN: (at least) 13 bytes for header.
9
Explicit headeryes
Yes for LoRaWAN: this is the low-level header that indicates coding rate, payload length and payload CRC presence. In plain LoRa it can be left out if both sides have these parameters fixed.
10
Low DR optimizeauto
Auto for LoRaWAN: correct for clock drift at low data rates; auto = enable for SF11..12 on 125kHz only, yes = enable for all.
11
Coding rate4 / 5
4/5 - 4/8. This is the error correction coding. Higher values mean more overhead.
12
Preamble symbols8
8 for all regions defined in LoRaWAN 1.0, can be different using plain LoRa.
13
Bandwidth125kHz
Typically 125, sometimes 250 or 500
14
15
OutputSF6SF7SF8SF9SF10SF11SF12
spreading factor; higher means more range and better reception, but also more airtime
18
Tsym0.5121.0242.0484.0968.19216.38432.768ms
19
Tpreamble6.27212.54425.08850.176100.352200.704401.408ms
20
payloadSymbNb78685853485348
number of symbols
21
Tpayload39.93669.632118.784217.088393.216868.3521572.864ms
22
Tpacket46.20882.176143.872267.264493.5681069.0561974.272
ms total airtime to send the full packet
23
TTN Fair Access Policy365208112602815
average messages/day for maximum of 30 seconds airtime on The Things Network
24
15.28.74.72.51.20.6
average messages/hour when sending all day
25
26
Duty cycle
Time between packet subsequent starts in the same subband
27
0.10%46.20882.176143.872267.264493.5681069.0561974.272s
28
1%4.6218.21814.38726.72649.357106.906197.427s
29
10%0.4620.8221.4392.6734.93610.69119.743s
30
31
For discussion see:
https://forum.thethingsnetwork.org/t/spreadsheet-for-lora-airtime-calculation/1190
32
For duty cycle see:
https://www.thethingsnetwork.org/forum/t/duty-cycle-time-on-air/122/27
33
For fair access policy see:
https://forum.thethingsnetwork.org/t/limitations-data-rate-packet-size-30-seconds-day-fair-access-policy-nodes-per-gateway/1300
34
35
36
Covered operating duration per day (TTN)
37
Message interval:30 sec10950624033601800840450s
38
182.51045630147.5min
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102