Power control and diversity for the downlink of CDMA systems
Ali A. Jalali, Paul G. Mermelstein · 2002
The authors study the capacity of a CDMA-based microcellular wireless system in the base to portable (downlink) direction. Narrowband CDMA with system bandwidth of 1.25 MHz is considered. Coherent reception using a pilot signal, BPSK modulation with 1/2 convolution codes, and power control are considered. Capacity of the downlink is evaluated as a function of multipath diversity, path loss exponent, and power control strategies. Both slow and fast power control on the downlink are considered. With slow power control, the capacity is severely limited. It is observed that fast power control significantly improves the capacity of the downlink. Finally, the effect of path loss exponent on the downlink capacity is illustrated.