Last modified by Xiaoling on 2024/08/16 11:25
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1 -XWiki.Xiaoling
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 +
13 13  = 2.  Analyze at the software side =
14 14  
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 AT+TXP=0 is always has the maximum output, but 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 (% 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.
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 +
27 27  [[image:image-20221006185826-1.png]]
28 28  
29 29  
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30 30  [[image:image-20221006185826-2.png]]
31 31  
32 32  
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.
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.
34 34  
35 35  
36 -End node actually value when TXP=0 and DR=0
37 +**End node actually value when TXP=0 and DR=0**
37 37  
38 38  (% border="1.5" cellspacing="4" style="background-color:#ffffcc; color:black; width:1002px" %)
39 39  |(% 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" %)**AS923**|(% style="width:400px" %)14dBm|(% style="width:362px" %)SF=12|(% style="width:102px" %)125Khz
45 45  
46 46  
47 -
48 48  == 2.2  Adaptive Data Rate (ADR) and set max distance ==
49 49  
50 50  
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73 73  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.
74 74  
75 75  
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 +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)
77 77  
78 78  
79 79  [[image:image-20221006185826-3.png]]
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85 85  
86 86  Below are the settings for longest distance transmission. ( will reduce battery life)
87 87  
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.
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.
91 91  
92 92  
93 93  
94 -= 3.  Installation Guidelines =
94 += 3.  Analyze at the hardware side =
95 95  
96 +== 3.1  Check if the antenna path is good ~-~- For LSn50v2 series end node ==
96 96  
97 -== 3.1  Check the use environment ==
98 98  
99 +a) Open Enclosure and Check if the antenna connection to module is good.
99 99  
101 +b) check if the connector match.
102 +
103 +
104 +[[image:image-20221016081725-1.png||height="426" width="706"]]
105 +
106 +
107 +
108 += 4.  Installation Guidelines =
109 +
110 +== 4.1  Check the use environment ==
111 +
112 +
100 100  First , User should notice: Radio link quality and performances are highly dependent of the environment.
101 101  
102 102  (% style="color:blue" %)**Better performances can be reached with:**
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106 106  * No high level radio interferes in the ISM band you use.
107 107  * At least 1 meter above the ground.
108 108  
109 -
110 -
111 111  (% style="color:blue" %)**Radio performances are degraded with:**
112 112  
113 113  * Obstacles: buildings, trees...
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117 117  
118 118  
119 119  
120 -== 3.2  Improve the Antenna ==
131 +== 4.2  Improve the Antenna ==
121 121  
122 122  
123 123  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.
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124 124  
125 125  
126 126  
127 -= 4.  Some real-world case =
138 += 5.  Some real-world case =
128 128  
140 +== 5.1  Server reason cause end node has problem on Join. ==
129 129  
130 -== 4.1  Server reason cause end node has problem on Join. ==
131 131  
132 -
133 133  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.
134 134  
135 135  
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143 143  
144 144  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]]
145 145  
156 +
157 +== 5.2 Chirpstack Default settings to 64 channels which cause Signal Poor. ==
158 +
159 +
160 +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.
161 +
162 +
163 +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.
164 +
165 +
166 +Above issue was confirmed and solved after set the ChirpStack support channels to sub-band2. See below for photos during debug.
167 +
168 +[[image:image-20221031233628-2.png]]
169 +
170 +
171 +[[image:image-20221031233759-3.png]]
172 +
173 +
174 +
175 +
176 +
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