What type of network technology to choose for specific application: BLE Mesh, Zigbee Mesh or Thread?

[N_Eugene]

Hello,

Our company is kicking off a project (while we are at the very beginning stage) where multiple nodes (up to 1K) should be connected within a mutual network. I wanted ask whether anyone can give an advice of which Mesh protocol technologies (Zigbee, BLE, Thread …) or their combination might fit the following specification:
• All devices (nodes) are battery powered only (except the coordinator/main controller)
• All devices will have the same functionality
• The network is closed and secured. No communication with devices that are outside of the family.
• The network should work in two modes:
a) Devices preset - might be initiated once every few days
b) Devices synchronization - will be initiated several times a day with very short command; for this mode the lag time should be as short as possible.
• No internet connection
• Messages will be transferred to all devices (nodes) simultaneously from coordinator/initiator unit.
• Working space is a big hall
• The maximum distance between coordinator/initiator and farthest device (node) is ~40m
• The maximum number of nodes is up to 1000 devices.
We will have to make a decision about the final h/w structure and I would appreciate any suggestion from your side.

Best Regards,
Eugene

[Susheel Nuguru]

Hi N_Eugene

I am thinking out loud here, just to help you out. 

• All devices (nodes) are battery powered only (except the coordinator/main controller)

 I guess this BLE Mesh is not in the scope if you have battery powered limitation on most of the nodes. Most BLE Mesh/Thread/Zigbee nodes (except the special sleepy nodes) need their receiver to be on most of the time and thus not very battery friendly.

Since 

• The maximum distance between coordinator/initiator and farthest device (node) is ~40m

1000 devices within a 40m radius seems to be very dense in terms of BLE. I am guessing the connections between one node and a few others close to it does not seem to be a problem. It should be possible that you can design something using BLE (not mesh) and make an application that simulates a mesh node. The challenge in this design would be do synchronize the sleep and wakeup times of the nodes, but if you manage to make them sleep for most of the time and spend very little time waking up, syncing their internal timers (anchor points) and do what transfer needs to be done etc. This is very much doable with just BLE, since this is best choice if you have a high priority on most nodes needed to be battery powered.

[N_Eugene]

Hi Susheel,

Thank you very much for such a quick response. Frankly, I have not thought this way though. It means that I will have to design my proprietary Mesh using BLE protocol. This Is your verdict, right?

One more question: I have checked the maximum distance requirement once again and it might be increased up to ~60m (not 40m). Can this change your suggestion?    

Best Regards,

 Eugene

[Susheel Nuguru]

N_Eugene said:

Thank you very much for such a quick response. Frankly, I have not thought this way though. It means that I will have to design my proprietary Mesh using BLE protocol. This Is your verdict, right?

 Yes, I think the fact that you said that most of the nodes will have to be battery powered except oontroller, narrowed down the meaningful options we have. The other Mesh technologies are not so power friendly when you take the overall network power requirements into consideration.

 

N_Eugene said:

One more question: I have checked the maximum distance requirement once again and it might be increased up to ~60m (not 40m). Can this change your suggestion? 

Using 1000 nodes in a big hall with a radius of 60 meters should still have reasonable number of failsafe connection between two nodes. So yes, i think this is a feasible option. 

[N_Eugene]

Susheel,

From your permission, I would like to ask a few more questions.

1. If in any case I would like to deploy standard ZigBee or BLE meshes, what is the maximum number of nodes that would be acceptable (from your stand point) with the above requirements?

2. Since the active mode of the mesh, where the communication between nodes might be established, occurs once in a few hours (short packets), might ZigBee's router or BLE relay be in the sleep mode? If so, this might dramatically reduce the power consumption of this unit.

Thank you for your support,

Eugene

[Susheel Nuguru]

Sorry for late response, many of us were on holidays and happy new year :)

N_Eugene said:

1. If in any case I would like to deploy standard ZigBee or BLE meshes, what is the maximum number of nodes that would be acceptable (from your stand point) with the above requirements?

 It is not possible to have all low powered nodes in Zigbee and BLE mesh. All low power nodes need to have a friend/coordinator node that have their radio-enabled all the time which is not a low power operation.

N_Eugene said:

2. Since the active mode of the mesh, where the communication between nodes might be established, occurs once in a few hours (short packets), might ZigBee's router or BLE relay be in the sleep mode? If so, this might dramatically reduce the power consumption of this unit.

 The cannot be in sleep mode while being a part of the network. If the routers sleep and wakeup, they need to rejoin the network which could be a time consuming process. But if you want the nodes to sleep for hours and wakeup and transmit data for few minutes, then rejoining the network might be a feasible option for your design. The only issue with rejoining networks, is that the network might look different than the network before sleep,