I am working on TI CC2530dk , using Contiki OS. I need two nodes to send the same signal at the same time to the sink. in order that the signals can be added at the receiver. How can I make the time synchronization between the sending nodes in case of applying real time testbed not simulation.
As far as I understand the problem, you would like to send the signals at approx. the same time, not exactly the same time. Exactly the same time could be a real challenge! Approx. the same time can be implemented relatively easy in two ways:
1.The receiver synchronises the senders by sending one packet with its own timestamp. The senders receive this packet and update their own time, then use normal timers and absolute time to schedule the sending of the signals.
2. The senders synchronise between each other. Let us assume that both have some sleeping schedules and that we do not know exactly when they will wake up. Once one of the wakes up, it starts sending periodically preambles with its own timestamp. It does that for a long time, such that it is guaranteed that the other one would wake up. When this happens, the second sender receives the preambles, updates its own timestamp and answers to the first sender . Here we have several possibilities of how to schedule the signals - the second sender could answer when it has scheduled the signal and the first one could take over the schedule. Or, they somehow differently agree on a schedule.
I would rather go for the first version, since it is simpler and will better syncronize the senders (they will receive the packet from the third node simultaneously).
thanks Anna. I have found this time synchronization mechanism in Contiki, my problem now how to use the mechanism in my contiki source code and then program the node
- Badges
- Science topic
- Similar topics
- Theoretical Physics
- Time