In addition, the sampling rate for the receiver needs to be about 100 times the data rate. Therefore, for this hypothetical system, the sampling rate would also need to be 600 mega-samples per second. All users in a CDMA system use the same frequency band. Each signal is spread out and layered on top of each other and overlaid using code spreading in the same time slot. The transmitted signal is recovered by using the PN code.
Data transmitted by other users looks like white noise and drops out during the reception phase.
Any narrowband noise is dispersed during the de-spreading of the data signal. The advantage of CMDA is the fact that the amount of bandwidth required is now shared over several users. However, in systems where there are multiple transmitters and receivers, proper power management is needed to ensure that one user does not overpower other users in the same spectrum. These power management issues are mainly confined to CMDA architectures. Let's look at an example.