@Hung -- Interesting. Isn't ANT mostly a star topology consisting of HUB and SENSOR? Sure the hubs can be linked together to form a tree or mesh, but I don't know if routing protocols are available. If not, it means application still has to take care of the inter-hub communication. Could you give more information on this?
@Ling:
You are right. I wasn't very correct to say that ANT protocol support mesh network directly, however it's pretty straight forward to implement an ANT node to relay data, which is necessary to create a "practical" mesh network.
For instance node A can setup a broadcast channel, node B can setup a receive channel and a broadcast channel, and node C can setup a receive channel. The synchronization, power management and pairing between A and B, B and C is fully handled by ANT.
However the application in each node will need to setup individual channels, and specifically node B will need to take the receive channel data from node A and write the data to its broadcast channel (this is very easy to do). Data on a broadcast channel can then be received by anyone on the same network.
The challenge here will be to inform node B that it should start to look for node A, if node C cannot receive data from node A directly.
However this might not be very difficult. For instance node C can by default be setup to try to receive data from node A, if no data is received within reasonable time node C can instead setup a broadcast channel to request anyone nearby to try to search for node A.
This can then be received by node B that by default has a receive channel open, then node B will setup a second receive channel to search for node A, once node B acquire node A, it can inform node C that it has found node A by sending data on the reverse channel back to node C. Since all channels are bidirectional this is straight forward.
Each node can setup up to 8 ANT channels, which can be a combination of receiver and broadcaster channels.
Unfortunately, at this moment, we don't have an example or app note for the implementation.
@Hung: Thanks for the detailed explaination. I browsed the pdf you linked above and noticed it actually refers ANT's mesh as "static mesh" and "practical mesh".
I came to BLE from ZigBee, so I tend to equate mesh with self-forming, self-healing network with AODV style routing. My mistake :) .
I am working on a project requiring a small scale of mesh on top of ANT+.
Number of nodes is limited to 64 right now.
Most of the nodes are stationary, but self-forming and self-healing is still required but seconds of time delay for these to happen is OK.
May not be a whole year, but I will definitely call 8 months is lucky!
