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CDMA capacity

- an overview capacity improvements provided by the use of CDMA

CDMA tutorial includes:

    •  CDMA basics tutorial
    •  CDMA spread spectrum techniques
    •  CDMA orthogonal spreading codes
    •  CDMA near-far problem
    •  CDMA capacity

One of the major reasons for the choice of CDMA for the 3G cellular services as well as a number of other communications systems, was the fact that it gave a significant improvement in capacity.

In fact CDMA capacity has been the subject of many papers and much discussion. It is dependent upon many factors and as a result, the exact determination of the improvements in CDMA capacity have been largely down to practical experience.

Orginal CDMA capacity claims

One of the chief claims for CDMA is that it gives significant improvements in network capacity. Original hype for CDMA proposed some very significant improvements. Expectations by some of the proponents of CDMA technology were for some very significant improvements:

• 18 fold increase in capacity when compared to AMPS (1G technology used in USA)
• 6 fold increase in capacity when compared to US TDMA (2G technology used in USA) - similar increases were also claimed over GSM.

In reality the original expectations were not fulfilled although increases of a factor of about two were seen when compared to US TDMA and GSM. This in itself was a significant improvement.

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