Background information
I am trying to wirelessly transmit a maximum packet size of about 204 bits from multiple trancievers to a central "base station" which consists of a transmitter and reciever. Lets call them BaseTx and BaseRx.
I have based the manchester transmit and recieve routines on nigels wireless tutorials.
All transmitters, recievers etc use the same frequency of 433.92Mhz. I know how to send data from the base station, to a specific tranciever, or multiple trancievers, sending data from a tranciever to the base station is equally easy.
My question
What happens if two trancievers, try to send at the same time to the one basestation using the same frequency? I could use different frequencies for each tranciever but this is not practical as i may have up to 30 trancievers, although it will probably be about 4 or 5 to begin with.
One idea I thought of was making the base station send out a continuous signal, sychronizing all trancievers, so that, they all have a specific "time" in which to send their data, AKA, time division multiplexing (TDM), however, this means that I will need to use at least 2 different frequencies, one for sending data, one sent out by basestation for sychronizing.
Another idea is, if two trancievers try to transmit simultaneously, after transmission, they wait for a "achnowledgment" from basestation to say data was recieved successfully. If the base station recieved both signals simultaneously on the same frequency, the data recieved is therefore corrupted as it cant differentiate between the two. The basestation therefore doesnt reply, or sends an "error" signal back.
After the trancievers which transmitted simultaneously have been waiting for a certain time with no reply from the base station, they assume their data wasnt recieved properly, therefore, tranciever A will wait for 5 seconds, transmit its data, and tranciever B will wait 10 seconds then transmit its data, which, will hopefully ensure data is transmitted one at a time the nex time around.
What do you guys think about the last method? Would it work? Does anybody know any good way of dealing with multiple transmitters trying to send data one reciever when they accidently send simultaneously?
thank you
I am trying to wirelessly transmit a maximum packet size of about 204 bits from multiple trancievers to a central "base station" which consists of a transmitter and reciever. Lets call them BaseTx and BaseRx.
I have based the manchester transmit and recieve routines on nigels wireless tutorials.
All transmitters, recievers etc use the same frequency of 433.92Mhz. I know how to send data from the base station, to a specific tranciever, or multiple trancievers, sending data from a tranciever to the base station is equally easy.
My question
What happens if two trancievers, try to send at the same time to the one basestation using the same frequency? I could use different frequencies for each tranciever but this is not practical as i may have up to 30 trancievers, although it will probably be about 4 or 5 to begin with.
One idea I thought of was making the base station send out a continuous signal, sychronizing all trancievers, so that, they all have a specific "time" in which to send their data, AKA, time division multiplexing (TDM), however, this means that I will need to use at least 2 different frequencies, one for sending data, one sent out by basestation for sychronizing.
Another idea is, if two trancievers try to transmit simultaneously, after transmission, they wait for a "achnowledgment" from basestation to say data was recieved successfully. If the base station recieved both signals simultaneously on the same frequency, the data recieved is therefore corrupted as it cant differentiate between the two. The basestation therefore doesnt reply, or sends an "error" signal back.
After the trancievers which transmitted simultaneously have been waiting for a certain time with no reply from the base station, they assume their data wasnt recieved properly, therefore, tranciever A will wait for 5 seconds, transmit its data, and tranciever B will wait 10 seconds then transmit its data, which, will hopefully ensure data is transmitted one at a time the nex time around.
What do you guys think about the last method? Would it work? Does anybody know any good way of dealing with multiple transmitters trying to send data one reciever when they accidently send simultaneously?
thank you