Effect of circular-cell approximation on the forward-link BER performance of a power-controlled CDMA system

The exact probability density function (PDF) for mobile distance from its own base station is derived for computing the forward-link performance of a Rayleigh-faded direct-sequence code-division multiple-access (DS-CDMA) cellular system with power control. Comparison with the commonly used 'circular-cell approximation' shows that the approximation gives more than 42% of error in the calculation of the variance of the mobile distance for a typical power control exponent of 4. Results also show that the previous approximation could under-estimate the forward-link capacity by more than 30%. Additionally, this newly derived PDF can also be used for arbitrary regular cell shapes by substituting their respective parameters.