ORIGINAL: dbcisco
ORIGINAL: dbspl
I'm not sure I follow this. There are 83 available channels in the 2.4Ghz band. Are you saying the data rate is reduced on just one of those channels, or the entire 2.4Ghz band? It would seem to make more sense if it were just 1 channel, but that also would leave you another 82 channels that would be uneffected.
The spread spektrum concept is that every .4 seconds the signal is transmitted over a different channel of at least 75 out of 83 channels available in a 30 second period.
Every 30 seconds the system has transmitted on at least 12 channels. As soon as you get 80 people flying (40 in the case of Spektrum) you are going to be sharing channels. As soon as you get 2 or more people flying you will have competition for those channels and that competition increases exponentially as the number of users increases. It also increase the amount of lag due to open channel searching and loss of data.
I think you are talking about frequency hopping here
Channel sharing (multiple users on a single carrier frequency with digital identification) is almost identical to the technology used in ethernet (WIFI and wired). Sharing the channel reduces the data through put for each user on the channel. This has been the bane of computer networking for years and it is always a problem, not a solution.
We are not talking about single frequency sharing here.
Lets look at what Wikiepia has to say about the generation of DSSS.
"Direct-sequence spread-spectrum transmissions multiply the data being transmitted by a "noise" signal. This noise signal is a pseudorandom sequence of 1 and −1 values, at a frequency much higher than that of the original signal, thereby spreading the energy of the original signal into a much wider band.
The resulting signal resembles white noise, like an audio recording of "static". However, this noise-like signal can be used to exactly reconstruct the original data at the receiving end, by multiplying it by the same pseudorandom sequence (because 1 × 1 = 1, and −1 × −1 = 1). This process, known as "de-spreading", mathematically constitutes a correlation of the transmitted PN sequence with the PN sequence that the receiver believes the transmitter is using."
Thus the data is spread over the frequency band of the channel in use.
Multi users can be accommodated by simply changing the seed for the PRN generator.