Cdma vs Tdma

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  • Topic: Time division multiple access, Cellular network, GSM
  • Pages : 8 (2680 words )
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  • Published : March 2, 2013
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CDMA versus TDMA
Term Paper :DTEC 6810

Submitted by:
Sabareeshwar Natarajan.
Fall 2006
DTEC 6810
Commun

INDEX:
Introduction:.................................................................................................................... 2 Voice encoding: .............................................................................................................. 2 TDMA:............................................................................................................................ 3 Advantages of TDMA: ............................................................................................... 4 Disadvantages of TDMA: ........................................................................................... 4 CDMA: ........................................................................................................................... 5 Advantages of CDMA: ............................................................................................... 6 Disadvantages of CDMA:........................................................................................... 6 Spectrum efficiency of CDMA compared with TDMA: ................................................ 6 CDMA Vs TDMA in travel: ........................................................................................... 7 Differences between CDMA and TDMA ....................................................................... 8 Conclusion: ..................................................................................................................... 8

1

Introduction:
In today’s world cell phone have become the single greatest tool in day today life. It has become a necessity that business associates should be able to communicate on the go. That’s why it has become so important to make choices in choosing which handheld device one should go for. A handheld device is selected according to its features and benefits, like does it provide access to internet and email or does it look slick and more. An important question when designing and standardizing cellular systems is the selection of the multiple access schemes. There are three basic principles in multiple access, FDMA (Frequency Division Multiple Access), TDMA (Time Division Multiple Access), and CDMA (Code Division Multiple Access). All three principles allow multiple users to share the same physical channel. But the two competing technologies differ in the way user sharing the common resource. TDMA allows the users to share the same frequency channel by dividing the signal into different time slots. Each user takes turn in a round robin fashion for transmitting and receiving over the channel. CDMA uses a spread spectrum technology that is it spreads the information contained in a particular signal of interest over a much greater bandwidth than the original signal. In TDMA users can only transmit in their respective time slot. Unlike TDMA, in CDMA several users can transmit over the channel at the same time.

Voice encoding:
Transmission of digital audio has two different issues. First is the way in which the stream of bits is transferred from one end to the other this is where the two technologies (CDMA and TDMA) differ from each other. Second is the compression algorithms used to encode the original audio into as small stream of bits as possible. These encoders (vocoders) take advantage of the predictable elements in human speech.

2

Although each technology has chosen their own unique vocoders, it is not necessary that one transmission method should use only particular vocoders. Voice encoding schemes differ from each other slightly in the way it approaches problem. Because of that, certain types of human voice sound better with some vocoders than they do with others. Due to this reason it has lead some people to choose certain technology over the other. All of the vocoders try to minimize the battery consumption by keeping the transmission of unnecessary...
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