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Sounds a little bit like CDMA. My professor in college didn't make it obvious why CDMA is any better than just assigning one carrier frequency to each transmitt

Sounds a little bit like CDMA. My professor in college didn't make it obvious why CDMA is any better than just assigning one carrier frequency to each transmitter. [1] The Wikipedia page for OFDM [2] says something like, if there's interference or attenuation affecting one frequency, it's better to spread that out instead of completely losing one channel. Which kinda makes sense, and would make more sense if I'd ever done RF work. I'd love to do SDR as a hobby some day. [1] The explanation in the book was something like, "See with 100 frequencies, you can create 100 chips and each user gets 1 chip, so you can support 100 users" which sounded pointless to me. [2] https://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing https://en.wikipedia.org/wiki/Orthogonal_frequency-division_...

aidenn0 2y ago
Any spread-spectrum technology has advantages when there is fading only some frequencies (a normal thing to happen in cities with these large surfaces that reflect RF called "buildings"). CDMA has an added advantage that the bit-error-rate is inversely proportional to the number of people communicating. With just giving everybody a single channel (or timeslot for TDMA), you either have enough or you don't. When you give everybody their own code, then you end up with either a small number of very high quality channels (few people communicating) or a large number of much lower quality channels (many people communicating). This was seen as advantageous when cell networks were rapidly growing. I don't think it's used much for terrestrial anymore, but it is still used in satellites.