The main DIFFERENCE between the two is the multiplexing technique they use for the WIRELESS communication between the MOBILE Station and BASE Station. CDMA uses different orthogonal (i.e. non-overlapping) codes for multiple users such that any number of users can COMMUNICATE with each other without any interference by others (due to orthogonality). On the other hand, GSM uses narrowband TDMA as the channel access scheme in which multiple users are assigned different time slots in which they can use the entire bandwidth available. It can allow eight calls on the same frequency simultaneously.

The main difference between the two is the multiplexing technique they use for the wireless communication between the Mobile Station and Base Station. CDMA uses different orthogonal (i.e. non-overlapping) codes for multiple users such that any number of users can communicate with each other without any interference by others (due to orthogonality). On the other hand, GSM uses narrowband TDMA as the channel access scheme in which multiple users are assigned different time slots in which they can use the entire bandwidth available. It can allow eight calls on the same frequency simultaneously.