srnet:
The LoRa devices can report the signal strength\SNR of the last received packet, so if the packets are tagged with the transmitter ID you can work out a crude triangulation from two seperate receivers, but you will still get the variation in RSSI due to reflections etc.
That is what i intend to do. LoRa uses DevAddR and Network addr, whose combination will always be unique.
LoRa is advertised or said to be, as a protocol which is resistent to Multipath propagation because of adaptive data rates.
While i understand multipath propagation can no way be nullified and must always exist. So I want to test how true this statement can be, or for that subject matter what are the scenarios that it can be resistent to Multipath propagation.
badritripathy92:
LoRa is advertised or said to be, as a protocol which is resistent to Multipath propagation because of adaptive data rates.
While i understand multipath propagation can no way be nullified and must always exist. So I want to test how true this statement can be, or for that subject matter what are the scenarios that it can be resistent to Multipath propagation.
That one is easy. Phase effects due to a delay are frequency dependent. No mystery there - it's communications theory 101.
badritripathy92:
LoRa uses DevAddR and Network addr, whose combination will always be unique.
LoRa is advertised or said to be, as a protocol which is resistent to Multipath propagation because of adaptive data rates.
Your miss understanding what LoRa is.
LoRa is a low level communication method, in the sense that AM or FM are. Although from the outside a LoRa device is entirely packet based, you cannot get inside what its doing to code or encode data.
There may well be systems that use LoRa for adding 'DevAddR and Network addr' functions but LoRa itself has no concept of this.
In a similar way it is possible to use LoRa for 'adaptive data rate' systems, but LoRa itself has no mechanism to implement this, thats up to the programmer.
LoRa is a low level communication method, in the sense that AM or FM are. Although from the outside a LoRa device is entirely packet based, you cannot get inside what its doing to code or encode data.
There may well be systems that use LoRa for adding 'DevAddR and Network addr' functions but LoRa itself has no concept of this.
In a similar way it is possible to use LoRa for 'adaptive data rate' systems, but LoRa itself has no mechanism to implement this, thats up to the programmer.
Yes, Thank you. i agree with everything that you have said. I was talking about LoRa protocol in general. I am aware the LoRa modulation is CSS modulation. As for ADR, i can always implement it as long as i stick to LoRa EU-constraints for power duty cycle.
allanhurst:
Still believe you can use RSSI for rangefinding?
Allan.
ps. As I remember the ETSI specs, the working dynamic range of a mobile phone receiver is > 80dB
that's > 100,000,000 :1.
Impressive, eh?
Well the link budget of LoRa is higher than 4G, so that may be a plus. And yes are right, DF or range finding over long range with varried terrain similar to what mobile reciever operates in, makes no sense. the maths c/B(Speed of light by bandwidth) for resoluting signals prove it as bandwidth for LoRa is 125 Khz, which is far too low.
But may be with Direct LOS and a range of 50ms or little more. The DF results can be reliable.
badritripathy92:
I was talking about LoRa protocol in general. As for ADR, i can always implement it as long as i stick to LoRa EU-constraints for power duty cycle.
LoRa is not a protocol.
There are no specific 'LoRa EU-constraints for power duty cycle'
There are EU-constraints for power duty cycle that apply to all types of RF transmission.
Well the link budget of LoRa is higher than 4G, so that may be a plus. And yes are right, DF or range finding over long range with varried terrain similar to what mobile reciever operates in, makes no sense. the maths c/B(Speed of light by bandwidth) for resoluting signals prove it as bandwidth for LoRa is 125 Khz, which is far too low.
But may be with Direct LOS and a range of 50ms or little more. The DF results can be reliable.
Duh.
Directional antennas may get you somewhere. RSSI wil not. And the signalling protocol and bandwidth is irrelevant.