How to receive data simultaneously on a RF module from multiple transmitters?

[aandavan]

In amy project i am using an RF module(433.92MHz both Tx and Rx). I have to continuously receive data from different transmitter(same frequency) at a time. Is it possible to receive data simulatneously from multiple transmitter. I am not able to receive data from more than one transmitter. Help me please.....

 

[RF-OM]

Re: Rf design problem

You need to separate the signals. For simple RF system it may be frequency division (FD) or time division (TD). More complex cases may include phase synchronization, code division or different combinations of signal parameters variations.

 

[aandavan]

Re: Rf design problem

For testing purpose i have used two transmitter and a single receiver. But i am not able to receive data from both the transmitter.

 

[RF-OM]

Re: Rf design problem

Your case requires multichannel radio link. May be you can add additional receiver(s) in order to receive different signals simultaneously on the same frequency, but in such case you will have the coexistence problem when transmitters creates mutual interference. RF system design with radio links budget must be done carefully in this case. If transmitters are separated and located under different azimuts, directed antennas may help.

 

[aandavan]

Re: Rf design problem

Do u have any specification for multi channel RF transmitters and receivers. If you have send me please

 

[the_risk_master]

Re: Rf design problem

I suggest you implement some coding on your transmitters, (e.g the first 5-bits are id codes) to identify incoming signals whether it came from what transmitter or channel (multiplexing is critical) otherwise your transmitter may experience capture effect

 

[pico]

Rf design problem

I confirmed that in your case, you are not able to receive data from more than one transmitter. Because it will be interfered each others.

 

[biff44]

Re: Rf design problem

The easiest thing to do, like mentioned above, is to time division multiplex the transmitters. There are many ways to do it, but one way is to listen for a break, and then transmit to the others. The receiving systems are programmed to shut up when they hear another one transmitting. In the old days, there were token-ring protocols developed for such a thing, for instance.

 

[aandavan]

Re: Rf design problem

HI the_risk_master,
can u help me by providing some sample code. I tried by changing the address of two transmitter and i have transmitted data, but the problem is it received the data from only one transmitter. Help me please..

 

[the_risk_master]

Re: Rf design problem

Ask you this; what modulation technique are you using?

 

[aandavan]

Re: Rf design problem

amplitude modulation

 

[the_risk_master]

Re: Rf design problem

AM is difficult for your case.

but I can suggest my past project:

AM-FM (dual modulation) transmitter , you'll need another demod for receiver

We'll use the FM mod for the data to be transmitted and received

the AM will carry the ID codes for the transmitters (I know it is not practical, and is expensive to do this, but this is just one of my weirdest experiments in RF)

the receiver has to demux the received signals

got my idea anyway?

I 'll send some of my diagrams if you don't get it