@strypey >Is the limit the number of connections, or the level of packet throughput?
It's both.

The greater the number of connections, the more connections the available bandwidth needs to be subdivided between and the more interference mitigations need to be applied (i.e. "delays" between "packets" need to be increased).


One example of the issue of too many clients is how the range of UMTS base stations would reduce the more clients that were connected (although later encoding schemes don't face this exact same limitation).

CDMA is analogous to a room full of pairs of people speaking different languages (with each pair rejecting languages that they don't understand as noise) - if too many pairs keep entering the room, every pair needs to move closer and closer to be able to hear the other.