1. GSM structure limits the number of users at certain QOS while CDMA system allows graceful degradation of QOS with increase in number of users within the cell
2. GSM works on hexagonal cell structure where each adjacent cell are having different frequency for operation and each cell can communicate with a maximum of fix number of mobile
users while CDMA there is not strict cell structure and every mobile user uses the entire freqency band.
3. GSM cells are relatively small in size and power efficient for mobile users while CDMA cells are big in size can accomodate more number of users but they are not as power efficient as GSM cells.
3. Hacking a GSM system is relatively easy than CDMA. CDMA is secure in this term
4. GSM system is popular in commercial application where QOS is more important while CDMA is popular for millitary and scientific experiments where data security and other issues are important. There days CDMA system is getting more popular due to no hard limit on number of users
