Unified spatial diversity combining and power allocation schemes for CDMA systems

In a wireless system, fading effects can be classified into large-scale effects and small-scale effects. We use power control to compensate for large-scale fading and exploit spatial diversity to combat small-scale fading. We characterize the SIR and our results show that when each user's small-scale fading effects are independent across the antennas, there is a clear separation between the gains of power control and diversity combining, and the two gains are additive (in decibels). We then characterize the Pareto-optimal transmission power allocation.