This page describes FDMA versus TDMA versus CDMA provides a difference between FDMA, TDMA and CDMA technologies. This post also describes multiple access techniques to make use of common resources by multiple users or subscribers.
FDMA:
- FDMA stands for frequency division multiple access, Here all entire band of frequencies is divided into multiple RF channel. Each carrier is allocated to different users.
- Segment the frequency band into disjoint subbands.
- Every terminal has its own frequency uninterrupted.
- Filtering in the frequency domain.
- FDMA is simple. established, robust.
- FDMA is inflexible, frequencies are a scarce resource
- Cell capacity is limited.
- FDMA is a hard handoff.
- Power efficiency reduced.
TDMA:
- TDMA stands for time division multiple access, here entire bandwidth is shared among different subscribers at fixed predetermined or dynamically assigned time slots.
- Segments sending time into disjoint time slots demand driven or it would be fixed patterns.
- All terminal are active for short periods of time of the same frequency.
- Synchronization in the time domain.
- TDMA is established fully digital, flexible.
- TDMA is guard space needed, synchronization difficult.
- Cell capacity is limited.
- TDMA is a hard handoff.
- When we are using TDMA full power efficiency is possible.
CDMA:
- TDMA stands for time division multiple access, here entire bandwidth is shared among different subscribers at fixed predetermined or dynamically assigned time slots.
- Spread the using orthogonal codes.
- All terminals can be active at the same place and also at the same moment uninterrupted.
- Signal speration for code puls special receivers.
- CDMA is flexible, less frequency needed soft handover.
- CDMA is a complex receiver, need more complicated power control for senders.
- No absolute limit on channel capacity but, it is interference limited for a system.
- CDMA IS soft handoff.
- When we are using CDMA full power efficiency is possible.