Difference between TDMA FDMA CDMA

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.









Popular Posts