Monday, September 7, 2009

TDMA & CDMA

TDMA
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According to TDMA in each signaling station Bandwidth is used in different time slots.In TDMA technology When a particular signaling station is using a certain timeslot say T1 it cannot be used by another signalling station T1 can be only used by the latter after first station is used.In satellite technology and For GSM mobiles mainlt TDMA technology is used .

CDMA
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For CDMa signalling station (mobile tower) there is no limitation for timeslot and bandwidth.It can transmit signals at any time at any frequency.For each station it have its own unique chip-code sequnce with binary logic 0 and 1 .For each clock chipcode will change .Chipcode sequence of paricular station will not be repeated for another station.Signals are secure in this technology.This is also known as Spread spectrum Multiple acess.For CDMA main parts are CDMA decoder & encoder .In CDMA logic 1 is respresented as +1 and logic 0 is represented as -1.

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