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Version 13.1 by Edwin Chen on 2022/10/31 23:35
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Edwin Chen 8.1 1 **Table of Contents:**
Edwin Chen 6.1 2
Edwin Chen 8.1 3 {{toc/}}
Edwin Chen 6.1 4
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Xiaoling 10.2 7 = 1.  OverView =
Edwin Chen 5.1 8
Xiaoling 10.2 9
Edwin Chen 5.1 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.
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Xiaoling 10.2 14 = 2.  Analyze at the software side =
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Xiaoling 10.2 16 == 2.1  LoRa parameters that effect distance ==
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Edwin Chen 5.1 19 Some settings in End Node will affect the transfer distance. They are:
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Xiaoling 10.4 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.
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Xiaoling 10.2 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.
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25 Below is the TXPower and DR table of EU868 Frequency band as reference.
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Xiaoling 10.4 27
Edwin Chen 5.1 28 [[image:image-20221006185826-1.png]]
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Xiaoling 10.2 30
Edwin Chen 5.1 31 [[image:image-20221006185826-2.png]]
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Xiaoling 10.4 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.
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Xiaoling 10.4 37 **End node actually value when TXP=0 and DR=0**
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Xiaoling 10.2 39 (% border="1.5" cellspacing="4" style="background-color:#ffffcc; color:black; width:1002px" %)
40 |(% style="width:134px" %)**Frequency band**|(% style="width:400px" %)**Output Power in LoRa Module (consider 2dB antenna)**|(% style="width:362px" %)(((
41 **Spreading Factor(Higher SF can transmit further)**
42 )))|(% style="width:102px" %)**Band Width**
43 |(% style="width:134px" %)**EU868**|(% style="width:400px" %)14dBm|(% style="width:362px" %)SF=12|(% style="width:102px" %)125Khz
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 |(% style="width:134px" %)**AS923**|(% style="width:400px" %)14dBm|(% style="width:362px" %)SF=12|(% style="width:102px" %)125Khz
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Xiaoling 12.2 48
Xiaoling 10.2 49 == 2.2  Adaptive Data Rate (ADR) and set max distance ==
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Xiaoling 10.2 52 **ADR** is the feature that Server will ask End Node to adjust the TXP and DR according to some rules in the server. This is for the purpose of Network Management and Optimize End Node battery life-time.
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Xiaoling 10.2 55 By default, ADR is turn on((% style="color:#037691" %)**AT+ADR=1**) (%%)so End node ADR feature is enable.
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Xiaoling 10.2 58 (% style="color:blue" %)**Normally, user can set the max distance by setting:**
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Xiaoling 10.2 60 (% style="color:#037691" %)**AT+ADR=0**
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Xiaoling 10.2 62 (% style="color:#037691" %)**AT+DR=0**
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Xiaoling 10.2 64 (% style="color:#037691" %)**AT+TXP=0**
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Edwin Chen 5.1 67 This can be downlink via the LoRaWAN downlink command, see [[this link>>url:http://wiki.dragino.com/xwiki/bin/view/Main/End%20Device%20AT%20Commands%20and%20Downlink%20Command/#H8.2UseDownlinkCommandtosetafixuplinkDR]] for reference.
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Xiaoling 10.2 71 == 2.3  Check for short distance problem ==
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Edwin Chen 5.1 74 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.
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Xiaoling 10.5 77 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)
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Edwin Chen 5.1 80 [[image:image-20221006185826-3.png]]
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Xiaoling 10.2 84 == 2.4  Best software settings for the longest distance ==
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Edwin Chen 10.1 87 Below are the settings for longest distance transmission. ( will reduce battery life)
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Xiaoling 10.6 89 * (% style="color:#037691" %)**AT+ADR=0**     (%%)~/~/  Disable ADR
90 * (% style="color:#037691" %)**AT+DR=  0**     (%%)~/~/  Use the smallest DR
91 * (% style="color:#037691" %)**AT+TXP=0**    (%%) ~/~/  Use max power.
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Edwin Chen 12.1 96 = 3.  Analyze at the hardware side =
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Edwin Chen 12.1 98 == 3.1  Check if the antenna path is good ~-~- For LSn50v2 series end node ==
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Xiaoling 12.2 100
Edwin Chen 12.1 101 a) Open Enclosure and Check if the antenna connection to module is good.
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Edwin Chen 12.1 103 b) check if the connector match.
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Edwin Chen 12.1 106 [[image:image-20221016081725-1.png||height="426" width="706"]]
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Edwin Chen 12.1 110 = 4.  Installation Guidelines =
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112 == 4.1  Check the use environment ==
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Edwin Chen 9.1 115 First , User should notice: Radio link quality and performances are highly dependent of the environment.
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Xiaoling 10.2 117 (% style="color:blue" %)**Better performances can be reached with:**
Edwin Chen 9.1 118
119 * Outdoor environment.
120 * No obstacles.
121 * No high level radio interferes in the ISM band you use.
122 * At least 1 meter above the ground.
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Xiaoling 10.2 124 (% style="color:blue" %)**Radio performances are degraded with:**
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Edwin Chen 9.1 126 * Obstacles: buildings, trees...
127 * Inner buildings environments.
128 * High ISM band usage by other technologies.
129 * Radio communication are usually killed with bad topographic conditions. It is usually not possible to communicate through a hill, even very small.
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Edwin Chen 12.1 134 == 4.2  Improve the Antenna ==
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Edwin Chen 9.1 137 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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Edwin Chen 12.1 141 = 5.  Some real-world case =
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Edwin Chen 12.1 143 == 5.1  Server reason cause end node has problem on Join. ==
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Edwin Chen 5.1 146 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.
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149 Below is the output log in gateway side ( SSH Access to Gateway and Check Station log)
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152 [[image:image-20221006185826-4.png]]
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155 The fix of this issue is to set the output power to a high value even server ask to send out 0dBm.
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Xiaoling 10.2 157 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]]
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