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My question is regarding the location of GSM channel access methods TDMA/FDMA.

Here is an illustration how voice is processed before reaching the base station on a tower:

enter image description here

It is not mentioning the multiplexing(TDMA/FDMA) part.

I have two questions:

1) Where is the modulation carried out? On the Base Station or before?

2) Where is the multiplexing(TDMA/FDMA) occurs? On the Base Station or before?

(Is base station just composed of antennas for transmission or also includes any of those processes?)

user16307
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1 Answers1

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All of the things shown in green boxes are carried out on the mobile station. The final red arrow means "transmit from mobile antenna to base station".

Think about it: the entire point of the modulation is to be able to transmit!

pjc50
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  • Oh you are right thanks. But how abot TDMA FDMA multiplexing? Do they occur on the BS tower or some where else? – user16307 Apr 23 '15 at 09:37
  • Again, the multiplexing is for the purpose of transmission. It's the "radio burst multiplexing" box on the diagram. – pjc50 Apr 23 '15 at 09:54
  • So TDMA and FDMA happend inside the phone? But dont you need many users data multiplex? Im confused – user16307 Apr 23 '15 at 09:56
  • The phone transmits in its timeslot. Other phones transmit in different timeslots. The base station demultiplexes these. – pjc50 Apr 23 '15 at 10:30