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Differentiate between CDMA, TDMA and FDMA.
written 5.2 years ago by | • modified 5.2 years ago |
Subject : Mobile Communication
Topic : Cellular Communication System
Difficulty : Medium
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written 5.2 years ago by | • modified 5.2 years ago |
Subject : Mobile Communication
Topic : Cellular Communication System
Difficulty : Medium
written 5.2 years ago by |
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 |