Advantages and disadvantages of CDMA

Advantages

• All users share the same frequency band at the same time, so spectrum use is efficient and capacity is high.
• Resistant to interference, jamming and multipath fading (RAKE receiver).
• Good security and privacy, since signals look like noise without the code.
• Soft handoff is possible, so fewer dropped calls.
• No strict frequency planning or time synchronisation of slots needed; graceful degradation when more users join.
• Lower power transmission is needed.

Disadvantages

• Near-far problem: a nearby strong transmitter swamps weak distant ones, so accurate power control is needed.
• Codes are only approximately orthogonal in practice, which causes multiple-access interference when users increase (self-interference limits capacity).
• Complex transmitters and receivers (code generation, synchronisation and power control), so costly.
• Needs wide bandwidth.
• Capacity is "soft" and falls as the noise level rises.