Can B-L072Z-LRWAN1 Build A Lora Network?

[New.Fish]

The  B-L072Z-LRWAN1 has two examples: ClassA and PingPong. ClassA requires a Multitech Gateway which is expensive, PingPong only for two nodes.

If I have 3 to 10 long range nodes, plan to do star network, One node is master and others are slave, can I use B-L072Z-LRWAN1 to build a private Lora network?

[T J]

Yes

everyone receives every packet.

[Tesla DeLorean]

With the right setting and a LoS everyone in a dozen KM

[New.Fish]

1. Everyone receives every packet ==>Use the PingPong example or ClassA example?
2. Would you please explain a little more details for "with right setting".

[T J]

all of your boards would have ot be set to the same channel...

did you get the Ping Pong working ?

Ping Pong is peer to peer, likely to be the right code..

I only used the Ping Pong, I only needed point to point.

Not sure about the ClassA, I never used it.

@Community member​ is an expert in LoRa.

[Tesla DeLorean]

I wouldn't say I'm expert, I know what I'm doing.

The Ping-Pong example just bounces packets back and forth in the air. You can modify it so one is a transmitter, or beacon, and have the other as a receiver, everything tuned to the same setting will be able to see the beaconing device.

Right settings, you can control the bandwidth and spreading factor, these will impact the distance packets can be reliably transmitted and decoded. 31 kbps packets I can get several KM, on the more conservative settings I can get out 12-14 KM

[ARana.2]

@Community member​ 

Hello There. I have tested the Ping Pong example and it's working fine for two device.

Now I want to modify the code in such a way that one become master and always in listening mode.

and the slave send messages to the master. but i want to use more channels of region. as on single channel i will not be able to received data of 14 devices.

is it possible to set multiple channels using time slice mechanism. e.g. for some amount of time master listen on one channel then moving on other channel? all the slave are transmitting on different fixed channel of particular band.

Thanks,

Ankit Rana

[Tesla DeLorean]

One should certainly be able to change frequency when starting a new RX operation. It's one of the fields in the radio structures.

LoRa moves through frequency and time, so messages starting at slightly different times don't tread on each other. The SX1276 isn't going to be able listen across multiple bands concurrently, whereas the SX130x parts can.

Also if you have time synchronization, for example via GPS/GNSS, your devices can send within their own time slot. This will obviously depend on the size/volume of data you're trying to move.

The Timeout mechanism includes the entire message receipt, this could probably be fixed so that it turns off the timeout once the message starts.

[ARana.2]

hello @Community member​ 

Thanks for your reply,

I have made one MASTER and one SLAVE using B-L072Z-LRWAN1 ST board.

I'm using Lora PhY layer to establish peer to peer network.

I have modified Ping_Pong example.

Task: I'm trying to achieve communication between MASTER and multiple SLAVE (typically 14 slaves) in INDIA region. MASTER first start listening on initial channel (for example CH_1) and then switching between all 7 channels of IND865 band. Each slave is sending data on fixed channel to master. (each slave is having particular wake-up time)

Problem: while switching to different channel in run time on master using setchannel function . device not adapting new channel.

see below image:

--> Initial channel on master is CH1 after that master is switching between CH0 and CH1, slave is having fixed CH0 and sending IMG on 10 seconds interval.

in this case master is not receiving any data from slave.

 

--> But if i modify slave channel to CH1, and initial MASTER channel is CH1.

then master is able to receive data from slave even if switching between CH0 and CH1.

 

--> So master is listening on initial channel only, if I change value run time it is not set on device.

Is it possible to change channel on run time? I have tried few things by pausing and resuming the ping_pong process.

[Tesla DeLorean]

I'm pretty sure it can change channel, the radio likely needs to be in the RF_IDLE mode, or you might need to use the fast hop mode. You don't want too change frequency mid-packet.

Using Rx Continuous mode?