The Dynamic Capacity in the Forward Link of CDMA Systems With Correlated BS Powers

The forward-link capacity of a power-controlled code-division-multiple-access (CDMA) system was commonly obtained by assuming equal base-station (BS) power throughout the system and neglecting the correlation and interaction among BS powers, which is rarely true in real CDMA systems. We propose an iteratively analytical process to determine the dynamic capacity in CDMA systems with unequal BS power by considering the correlation and interaction among BS powers. Simulation results show that the Erlang capacity is significantly different by modeling the BS power as a random variate instead of a constant value. We also show that correlation among BS powers can be up to 0.13, and the reduction in Erlang capacity can be up to 30%. To efficiently evaluate the dynamic Erlang capacity and correlation among BS powers, a closed-form expression of the capacity in terms of certain outage and blocking probabilities is obtained by using the distribution of the BS power.