Algorithm 2: Time interval assignment and operation algorithm for the coordinator.

Data: Time intervals TI for priorities are configured.

Input: Received message from the device D.

Output: Assigned time interval TI(P) for the device D.

1 ZigBee communication initiation of device D

2 if D not assigned with time interval then

3  send Offer message with available priorities to D at the time T

4  wait for Selection message from D with priority P

5  assign D with time interval TI(P) based on the time T

6 repeat

7  wait for data from D in time interval TI(P)

8  send Acknowledgement to D

9 until D communicates out of time interval TI(P)