collision during transmmison

can any1 help me to solve tis problem? thank you very much

let say i have 3transmitters, and only 1 receiver. how can i control it to avoid data collision when transmmision occur.

Your question is kind of vague.
Define your application & scenario first.

Still, If your transmitters are transmitting at same time & same frequency.
you can modulate your signal at transmitter side.
There should be specific signature for perticular transmitter.

If you have transmitters rather than transceivers, they can't avoid collisions at all. At best, they can minimize there likelihood.

thanks for replied...

ya.. i m using same frequency and same time also. let say if i want to search this topic. which words i should "search" and any others recommendation?

the actual situation is like below:

i have some sensors from different locations, so each location require to transmit signal which is received by sensors. and signals are collected by a receiver.

Time multiplex is the only way. Because the transmitters most likely don't have an absolute time, you need to make the
duty cycles low and possibly use pseudo random variation of transmission time. Low duty cycle would be required by SRD
regulations for this kind of application anyway.

I expect, the individual sensors are using unique IDs.

Read about Alohanet. This problem has been solved many times over. Good luck.