Differentiate between CDMA and FDMA ?

a.) CDMA and FDMA 

CDMA

- Same frequency is used by every user and simultaneous transmission occurs
- Every narrowband signal is multiplied by wideband spreading signal, usually known as codeword
- Every user has a separate pseudo-codeword, i.e., orthogonal to others
- Only the desired codeword is detected by the receivers and others appear as noise
- It is mandatory for the receivers to know about the transmitter’s codeword

FDMA

- When the channel is not in use, it sits simply idle
- Bandwidth of Channel is relatively narrow (30 KHz), known as narrowband system
- Little or no equalization is needed for spreading symbol time
- Analog links are suitable for FDMA
- Framing or synchronization bits are not needed for continuous transmission
- Tight filtering is needed to minimize interference
- Combined with FDD for duplexing