Reverse-Link Rate Control Algorithms with Fairness Guarantees for CDMA Systems

We propose a set of distributed rate control algorithms for the reverse-link of CDMA systems using a pricing mechanism. In the derivation, we assume that the base station broadcasts a real-valued feedback in order to control the reverse activity level. In addition, we assume that the access terminals are able to transmit data at any rate within a finite range, and that the transmission power is a linear function of the transmission rate. For a specific utility function, we show that the proposed algorithm achieves social optimality, satisfies an interference power constraint, and exhibits desirable short- and long-term fairness behaviors. We then modify this algorithm so that it can be applied to the case when the transmission power is a convex function of the transmission rate. Next, we consider the case that the feedback parameter is a single reverse activity bit, and the underlying rates are elements of a discrete set of admissible rates. This scenario is similar to that of the IS-856 standard. We further modify our algorithms so that they can be applied to this system setup, and verify the performance using numerical simulations. It is demonstrated that our algorithms exhibit short- and long-term fairness behavior for this realistic scenario.