Low Power Wide Area Networks (lpwan): Technology Review And Experimental Study on Mobility Effect

LPWAN FOR UAVS

Deploying an LPWAN network using UAVs is an interesting topic which can help serve various application areas. UAVs offer an inherent attribute of being able to vary its altitude and move in a three dimensional space compared to other land moving vehicles. A LPWAN network deployed using UAV can serve carious applications like:

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  Search and rescue.
  
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  Surveillance of area which might inaccessible to man.
  
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  Use of UAVs to track weather conditions like storm or chasing a tornado to track its
  

path.

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  UAVs can also serve as an aerial base station extending the range of LPWAN network.
  

Even with such promising use cases of deploying an LPWAN network using

UAVs, there are technical challenges that need to be addressed:

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  Air to Ground communication : It is known that the communication medium used for wireless signal propagation does have an effect on network performance. It is also know that air to ground communication is more susceptible to blockage. As we can see from our results that concrete structures have an effect on LPWAN communication, it is important to consider the effect of same on air to ground communication [35].
  
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  Deployment in 3-D space : Since UAVs are able to adjust their height along with their linear velocity, it adds an extra degree of freedom to its motion. A LPWAN network deployed using UAVs needs to be done while considering the effect of altitude along with velocity in 3D space as our results show that mobility does have a huge impact on network performance in 2D space [35].
  

4. GENERAL GUIDELINES

Some of the general guidelines to improve network performance under mobility conditions are:

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  Spreading Factor : Use higher spreading factor wherever possible. A higher spreading factor helps to improve communication range [10].
  
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  Gateway Positioning : In outdoor environment, placing a gateway as high as possible helps to decrease network interference from its surroundings.
  
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  Data Packet design : It is very important to only transmit the data that is needed and leave the junk data out as our results show that the size of the data packet has a big impact on end to end delay and packet loss rate in case of mobility.
  
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  Antenna : Using a more powerful antenna and also adjusting it at a specific angle helps to increase network performance and range. It was seen that the range of LL RXR 27 module increased when we replaces the trace antenna with ANT-916 antenna tuned for 915 MHz with a maximum gain of 1.9 dBi or less. Adjusting antenna at certain angle also helps to improve the network performance
  

8.