This arrangement will only work if the frequency of transmissions from the
Outstations is low. The Outstations either transmit randomly, trusting that
the probability of a collision is so low that it will not occur (unlikely).
Or you equip each Outstation with a real-time clock and allocate each one a
transmission time.  Outstation 1 = First Second after each minute, Second
Outstation = Second Second after each minute ............

The practical way of doing it is to use transceivers at each Outstation and
the Base Station. Then using a bi-directional protocol such as Aloha.

Look up Aloha Protocol using Search Engines. However, here are two
references to get you started.

Pure Aloha Protocol
http://mars.mcs.kent.edu/ksuthesis/node19.html

Slotted Aloha Protocol
http://mars.mcs.kent.edu/ksuthesis/node20.html

Without two way transmission how will the Outstation know if its
transmission was successfully received without being corrupted by another
Outstation ?

Could you overcome it by transmitting the same data frame multiple times ?
How would the receiver know it was a retransmission if it successfully
received several of those transmissions? What does multiple transmissions do
to channel occupancy an the probability of sending a transmission from any
one Outstation without the transmission being corrupted by another
Outstation?

You can get some idea of what happens by doing some simple modelling using a
spreadsheet.

Regards

Chris


Jose S Samonte Jr Wrote:
Thank you so much. I really hope that you would help me. =)

I'm using sir a PIC16F877.
I'm using just a simple protocol for transmission; preamble, sync bytes,
data,
checksum. Baud date I'm using is 2400 bps. PIC speed is 4MHz.

What can you suggest sir in a multiple(16) transmitter/single receiver
system?
Would fixed delays/waiting time (w/c is different for each transmitter) do?
Or
would random delays be better?

Thank you so much.
Kindest regards. =)


P.S. I'm sorry if I resent this e-mail. I made a mistake with the Subject.
Sorry...=)


promero <promero@INSITEL.COM.CO> wrote:
Could you be more explicit? what kind of pic are you using?
Which protocol do your transmissions follow? How fast is your system
(microcontroller speed vs. communication speed)? What do you mean exactly by
"waiting time"?

"Jose S. Samonte Jr." wrote:

> Hello to everyone! =)
> I hope that any would help me with my problem on multiple
transmitter/single
> receiver system.
> How would I be able to compute for the waiting time for each transmitter
> if there are 16 transmitters for a single receiver?
> Thank you so much.
> Best regards.
>
> ____________________________________________________________________

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