Each user in a CDMA system uses a different code to modulate their signal.
Choosing the codes used to modulate the signal is very important in the performance of CDMA systems.
This leads to a general requirement in any asynchronous CDMA system to approximately match the various signal power levels as seen at the receiver.
In a CDMA system, the same frequency can be used in every cell, because channelization is done using the pseudo-random codes.
Since adjacent cells use the same frequencies, CDMA systems have the ability to perform soft hand offs.
In contrast, CDMA systems use the soft hand off, which is undetectable and provides a more reliable and higher quality signal.
In CDMA systems, a physical channel corresponds to a particular spreading code, hence the name (Received signal code power).
The research addressed fundamental issues in mobility due to switching, signaling and effects of power control and coding in CDMA systems.
The near-far problem is particularly difficult in CDMA systems, where transmitters share transmission frequencies and transmission time.
In CDMA systems and similar cellular phone-like networks, the problem is commonly solved by dynamic output power adjustment of the transmitters.