Congestion with many XBee Pros in close proximity to each other

Question

I've got about a 70 XBP24 (XBee Pro 802.15.4) units that I would like to deploy on some moving objects (think ATV's and horses).

They will be using the API to communicate to each other (this is many-to-many, but not using broadcasting - just simply 16 and 64 bit addressing in API mode).

Do I need to worry about collisions or congestion with this number of XBee's? Especially if they all get talking at once... If so, will packets just get dropped, or are errors returned if there is a collision?

Answer 1

It does not really matter the total number of node so much as it is the total amount of data being sent. As long as you do not exceed the streaming limit of 80kbps, you should be fine. With that said, if a data collision occurs, automatic retries should kick in. Otherwise you should get a response in the API status frame indicating if it was received or not. If it was not received, you may want to re-transmit the packet. But that is dependent on your software protocol if that is necessary or not.