【71-75】cdma for cellular systems can be described as follows.as with fdma，ech cell is allocatedafrequency（71），which is split into two parts，half for reverse（mobile unit to base station）and halffor（72）（basestation to mobile unit）.for full-duplex（73）.a mobile unit uses both reverse andforwardchannels.transmission is in the form of direct-sequence spread（74），which uses a chipping codetoincreasethe data rate of the transmission，resulting in an increated signal bandwidth.multiple accessisprovidedby assigning（75）chipping codes to multiple users，so that the receiver can recover the transmissionofan individual unit from multiple transmission.
