Difference Between SDMA , TDMA , FDMA and CDMA in Tabular form.

SDMA : Space-division multiple access
TDMA : Time-division multiple access
FDMA : Frequency-division multiple access
CDMA : Code-division multiple access

ApproachSDMATDMAFDMACDMA
IdeaSegment spaced into cells or sectors.Segments sending time into disjoint time slots demand driven or fixed patterns.Segment the frequency band into disjoint subbandsSpread the spectrum using orthogonal codes.
TerminalsOnly one terminal can be active in one cell or one sector.All terminals are active for short periods of time on same frequency.Every terminal has its own frequency uninterruptedAll terminals can be active at the same place at the same moment uninterrupted.
Signal separationCell structure, directed antennasSynchronization in time domainFiltering in the frequency domain.Code plus special receivers.
Transmission schemeContinuousDiscontinuousContinuousContinuous
Cell capacityDepends on cell areaLimitedLimitedNo absolute limit on channel capacity but it is an interference limited system
AdvantagesVery simple, increases capacity perEstablished fully digital, flexibleSimple, established, robustFlexible, less frequency planning needed, soft handover
DisadvantagesInflexible, antennas typically fixedGuard space needed (multipath propagation), synchronization difficultInflexible, frequencies are scarce resourceComplex receivers, needs more complicated power control for senders
CommentOnly in combination with TDMA, FDMA or CDMA usefulStandards in fixed networks, together with FDMA or SDMA used in many mobile networksTypically combined with TDMA and SDMAStill faces some problems, higher complexity, lowered expectations, will be integrated with TDMA or FDMA
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One thought on “Difference Between SDMA ,TDMA , FDMA , CDMA

  • 19/08/2018 at 6:46 am
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    It works really well for me

    Reply

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