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Last modified by Xiaoling on 2024/08/16 11:25
From version 19.1
edited by Edwin Chen
on 2022/11/30 10:22
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To version 10.2
edited by Xiaoling
on 2022/10/15 16:21
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1 -XWiki.Edwin
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10 10  In real-world deployment for LoRa, distance is a common topic. We always want to have the longest distance. This chapter shows some instructions for how to improve this.
11 11  
12 12  
13 -
14 14  = 2.  Analyze at the software side =
15 15  
15 +
16 16  == 2.1  LoRa parameters that effect distance ==
17 17  
18 18  
19 19  Some settings in End Node will affect the transfer distance. They are:
20 20  
21 -* (% style="color:blue" %)**TXPower: **(%%)This means the output power from End Node. There is a command [[AT+TXP>>url:http://wiki.dragino.com/xwiki/bin/view/Main/End%20Device%20AT%20Commands%20and%20Downlink%20Command/#H7.14TransmitPower]] can be used to set the output power. TXP parameters follow the LoRaWAN regional document (rp2-1.0.3-lorawan-regional-parameters.pdf). Set to (% style="color:#037691" %)**AT+TXP=0**(%%) is always has the maximum output, but (% style="color:#037691" %)**AT+TXP=0**(%%) has different value in different frequency bands.
21 +* (% style="color:blue" %)**TXPower: **(%%)This means the output power from End Node. There is a command [[AT+TXP>>url:http://wiki.dragino.com/xwiki/bin/view/Main/End%20Device%20AT%20Commands%20and%20Downlink%20Command/#H7.14TransmitPower]] can be used to set the output power. TXP parameters follow the LoRaWAN regional document (rp2-1.0.3-lorawan-regional-parameters.pdf). Set to AT+TXP=0 is always has the maximum output, but AT+TXP=0 has different value in different frequency bands.
22 22  
23 23  * (% style="color:blue" %)**Data Rate(DR): **(%%)This is a combination of Spreading Factor and Band Width. Lowest Data Rate (DR=0) always has the longest transmit distance in LoRaWAN protocol.
24 24  
25 25  Below is the TXPower and DR table of EU868 Frequency band as reference.
26 26  
27 -
28 28  [[image:image-20221006185826-1.png]]
29 29  
30 30  
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31 31  [[image:image-20221006185826-2.png]]
32 32  
33 33  
34 -Set (% style="color:#037691" %)**AT+TXP=0**(%%) **and** (% style="color:#037691" %)**AT+DR=0**(%%) will always has the longest transmit distance. But note that different frequency band has different TXP and DR coding according to LoRaWAN regional settings. Below is example for EU868, US915 and AS923 compare for example.
33 +Set AT+TXP=0 and AT+DR=0 will always has the longest transmit distance. But note that different frequency band has different TXP and DR coding according to LoRaWAN regional settings. Below is example for EU868, US915 and AS923 compare for example.
35 35  
36 36  
37 -**End node actually value when TXP=0 and DR=0**
36 +End node actually value when TXP=0 and DR=0
38 38  
39 39  (% border="1.5" cellspacing="4" style="background-color:#ffffcc; color:black; width:1002px" %)
40 40  |(% style="width:134px" %)**Frequency band**|(% style="width:400px" %)**Output Power in LoRa Module (consider 2dB antenna)**|(% style="width:362px" %)(((
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44 44  |(% style="width:134px" %)**US915**|(% style="width:400px" %)20 or 22 dBm (depends on max output of module)|(% style="width:362px" %)SF=10|(% style="width:102px" %)125Khz
45 45  |(% style="width:134px" %)**AS923**|(% style="width:400px" %)14dBm|(% style="width:362px" %)SF=12|(% style="width:102px" %)125Khz
46 46  
46 +
47 +
47 47  == 2.2  Adaptive Data Rate (ADR) and set max distance ==
48 48  
49 49  
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72 72  According to the above technology, if we have a problem on the distance, we can first check if the end node is trying to longest distance modulation already. We can see that from the LoRaWAN server. Below is an example from Chirpstack.
73 73  
74 74  
75 -We can see the traffic in gateway's page and know that the distance is SF12 / BW125. (note, server is not able to know Transmit Power settings from End Node)
76 +We can see the traffic in gateway’s page and know that the distance is SF12 / BW125. (note, server is not able to know Transmit Power settings from End Node)
76 76  
77 77  
78 78  [[image:image-20221006185826-3.png]]
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84 84  
85 85  Below are the settings for longest distance transmission. ( will reduce battery life)
86 86  
87 -* (% style="color:#037691" %)**AT+ADR=0**     (%%)~/~/  Disable ADR
88 -* (% style="color:#037691" %)**AT+DR=  0**     (%%)~/~/  Use the smallest DR
89 -* (% style="color:#037691" %)**AT+TXP=0**    (%%) ~/~/  Use max power.
88 +* (% style="color:#037691" %)AT+ADR=0     (%%)~/~/  Disable ADR
89 +* (% style="color:#037691" %)AT+DR=  0     (%%)~/~/  Use the smallest DR
90 +* (% style="color:#037691" %)AT+TXP=0    (%%) ~/~/  Use max power.
90 90  
91 -= 3.  Analyze at the hardware side =
92 92  
93 -== 3.1  Check if the antenna path is good ~-~- For LSn50v2 series end node ==
94 94  
94 += 3.  Installation Guidelines =
95 95  
96 -a) Open Enclosure and Check if the antenna connection to module is good.
97 97  
98 -b) check if the connector match.
97 +== 3.1  Check the use environment ==
99 99  
100 100  
101 -[[image:image-20221016081725-1.png||height="426" width="706"]]
100 +First , User should notice: Radio link quality and performances are highly dependent of the environment.
102 102  
103 -
104 -
105 -= 4.  Installation Guidelines =
106 -
107 -== 4.1  Check the use environment ==
108 -
109 -
110 -First , User should notice: Radio link quality and performances are highly dependent of the environment.Even you have the same hardware and antenna, Different installation will result in different performance.
111 -
112 112  (% style="color:blue" %)**Better performances can be reached with:**
113 113  
114 114  * Outdoor environment.
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116 116  * No high level radio interferes in the ISM band you use.
117 117  * At least 1 meter above the ground.
118 118  
109 +
110 +
119 119  (% style="color:blue" %)**Radio performances are degraded with:**
120 120  
121 121  * Obstacles: buildings, trees...
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123 123  * High ISM band usage by other technologies.
124 124  * Radio communication are usually killed with bad topographic conditions. It is usually not possible to communicate through a hill, even very small.
125 125  
126 -== 4.2  Improve the Antenna ==
127 127  
128 128  
120 +== 3.2  Improve the Antenna ==
121 +
122 +
129 129  In some case, we have to install the device inside the chamber or next to a metal case. So the signal between the antenna and the receiver (gateway) is blocked by the metal. This will greatly reduce the signal. In such case, we can consider using antenna extend cable to extend the antenna to a better position.
130 130  
131 131  
132 132  
133 -= 5.  Some real-world case =
127 += 4.  Some real-world case =
134 134  
135 -== 5.1  Server reason cause end node has problem on Join. ==
136 136  
130 +== 4.1  Server reason cause end node has problem on Join. ==
137 137  
132 +
138 138  In one case, the customer is using AWS IoT Core and gateway to connect to AWS via Basic Station Connection, Frequency Band is AU915 sub-band 2. For some unknown reason, AWS always set downlink power to 0dBm, which cause the gateway only emit a very low power and lead to a short distance for sensor.
139 139  
140 140  
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148 148  
149 149  Reference Link:  [[http:~~/~~/wiki.dragino.com/xwiki/bin/view/Main/Change%20Gateway%20Power/#H1.A0Overview>>http://wiki.dragino.com/xwiki/bin/view/Main/Change%20Gateway%20Power/#H1.A0Overview]]
150 150  
151 -
152 -== 5.2 Chirpstack Default settings to 64 channels which cause Signal Poor. ==
153 -
154 -
155 -In this case, User use a Chirpstack LoRaWAN server with default settings. The Frequency Band is US915 and default settings of Chirpstack has all channels ( All sub-bands , total 72 channels) enable. User use a LDS03A and a LPS8N LoRaWAN gateway for the test.
156 -
157 -
158 -There is a strange issue: LDS03 has a very good RSSI ( RSSI=-40) during OTAA Join. But The LDS03A give a very poor RSSI after OTAA Join. After debug, it proves that the issue is with ChirpStack Frequency band settings. The ChirpStack server enables all 72 channels and the LDS03A will also use all channels after OTAA Join, but the LPS8N only can support 8 channels and set to Sub-Band2. When the LDS03A sends an uplink packet in the channel LPS8N doesn't support, because LDS03A is very close to LPS8N, LPS8N pick up this not support frequency and send to server. So in the platform we see a uplink packet with very poor RSSI.
159 -
160 -
161 -Above issue was confirmed and solved after set the ChirpStack support channels to sub-band2. See below for photos during debug.
162 -
163 -[[image:image-20221031233628-2.png]]
164 -
165 -
166 -[[image:image-20221031233759-3.png]]
167 -
168 -
169 -[[image:image-20221101000006-1.png||height="353" width="931"]]
170 -
171 -
172 -
173 -
174 174  
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