CDMA stems from military anti-jamming system and CDMA signal occupies the entire frequency band. Therefore, for same bandwidth, capacity of CDMA system is 4 – 5 times of that of GSM system, greatly lowering network blocking, so connectivity is naturally higher. CDMA adopts soft cut off technology, that is to say, cut the mobile phone from the original base station only when it is transferred to the other base station’s exclusive coverage area. In this way, mobile phone will not drop call and continuous communication is ensured. Through applying wideband carrier frequency transmission and advanced power control technique, CDMA overcomes decline of signal path and avoid unstable signal phenomenon; it also uses error correction coding channel to make users keep stable call even in the magnetic suspension train with the speed per hour as high as 430km.