LoRa mesh vs BLE mesh?

[S.G.]

Hi!

I have been using LoRa for communication for my product. I'm looking into using BLE mesh.

I have a couple of hundred sensors, all 1-2m apart from each other. Here a mesh network would be great. LoRa is doing the job for 10 sensors, but I haven't tested the mesh capabilities.

Any suggestions on using BLE mesh vs LoRa mesh? What would the gateway situation be? My main priority is low-power.

The sensors are all outdoors, the gateway would be outdoors too.

[bjorn-spockeli]

Hi S.G.

If your priority is low-power, then you should be aware that while the Bluetooth Mesh does support battery powered nodes, you will need to have a set of "backbone" nodes that are powered. This si because the BLuetooth mesh is a flooding mesh, i.e. connection-less, and nodes will therefore need to keep their receivers on at all times to listen for messages to relay to other nodes. 

The Bluetooth Mesh does not define any gateway so you will have to connect a Bluetooth MEsh node to a device that has IP connectivity and perform the translation between mesh and IP, e.g. a smartphone or a Raspberry PI or similar. 

Best regards

Bjørn

[S.G.]

Hi, thanks for the reply!

How many backbone devices should there be for lets say 100 nodes? (the nodes are 1-2m apart)

Do you have some numbers for low-power with BLE mesh? What kind of consumption should I expect?

[bjorn-spockeli]

You should be able to get 50m range outdoors with line of sight between the nodes while transmitting at +4dBm. So I think somewhere between 10-20 should do, a bit dependent on the distribution of the nodes. 

The current consumption will be dependent on how often you transmit data. You can use our Online Power Profiler to estimate the average current consumption of a node that wakes up at a given interval and transmits the sensor data. A full mesh packet payload is 11bytes and sending one packet per 5 seconds gives you an average of 4.5uA while transmitting at +4dBm and using the DCDC. 

You can find with the calculator here: https://devzone.nordicsemi.com/nordic/power/

Bjørn

[awneil]

S.G. said:

LoRa mesh

Is that a thing?

While there do seem to be a few people talking about mesh using LoRa, it all seems to be proprietary - not  a standard thing?

Have you seen this:

https://devzone.nordicsemi.com/f/nordic-q-a/48449/ble-5-or-lora

S.G. said:

I have a couple of hundred sensors, all 1-2m apart from each other.

LoRa should be able to cope with that fine without the need for meshing.

S.G. said:

Here a mesh network would be great

Really?

Meshes add a great deal of complexity! If you can do without a mesh, then do it!

[awneil]

bjorn-spockeli said:

If your priority is low-power, then you should be aware that while the Bluetooth Mesh does support battery powered nodes, you will need to have a set of "backbone" nodes that are powered. This si because the BLuetooth mesh is a flooding mesh

So how does this compare to other meshes; eg, Zigbee and Thread ... ?

EDIT

Google found this comparison https://www.eetimes.com/author.asp?section_id=36&doc_id=1333265# - but it doesn't address power consumption.

Other comparisons seem similarly focussed.