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Differentiate between CDMA, TDMA and FDMA.

written 7.1 years ago by teamques10 ★ 70k

•   modified 7.1 years ago

Subject : Mobile Communication

Topic : Cellular Communication System

Difficulty : Medium

mobile communication

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written 7.1 years ago by teamques10 ★ 70k

Approach	TDMA	FDMA	CDMA
Idea	Segments sending time into disjoint time slots demand driven or fixed patterns.	Segment the frequency band into disjoint subbands	Spread the spectrum using orthogonal codes.
Terminals	All terminals are active for short periods of time on same frequency.	Every terminal has its own frequency uninterrupted	All terminals can be active at the same place at the same moment uninterrupted.
Signal separation	Synchronization in time domain	Filtering in the frequency domain.	Code plus special receivers.
Transmission scheme	Discontinuous	Continuous	Continuous
Cell capacity	Limited	Limited	No absolute limit on channel capacity but it is an interference limited system
Advantages	Established fully digital, flexible	Simple, established, robust	Flexible, less frequency planning needed, soft handover
Disadvantages	Guard space needed (multipath propagation), synchronization difficult	Inflexible, frequencies are scarce resource	Complex receivers, needs more complicated power control for senders

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