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en.wikipedia.org/wiki/High-Speed_Downlink_Packet_Access

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Posted by crouse

en.wikipedia.org/wiki/High-Speed_Downlink_Packet_Access

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Posted by crouse

In CDMA all the users use the same frequency and transmit at the same time.But they use different codes(a psuedo random PN sequence of +/-1) which have very less correlation.The code is multiplied by the data symbol and this increases the band width.For the intended receiver who multiplies the correct PN sequence the original symbol transmitted can be obtained.The data transmitted by others appears as noise which adds in power due to the incorrect multiplication of PN code.The ratio of this coded band width to the band width of the original symbol is called the processing gain (G).
Processing gain is nothing but the band width expansion taken place.

Let Eb/N0(min) be needed for a given probability of error p.

Then maximum number of users N (approximate) is given by N=G/(Eb/N0)min

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Posted by Mannai_Murali

The maximum no of simultaneous users using a channel in CDMA is given by the term pole capacity which is a hypothetical figure as it is never to be achieved.The actual no should be given by the term loading factor (fraction of pole capacity)....It should lie between 50% and 75%

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Posted by avanindrakumar