Power and data rate assignment for maximal weighted throughput: a dual-class 3G CDMA scenario

Relevant to the uplink of a VSG-CDMA system, a technique part of 3G standards, this work investigates power and data rate allocations that maximize the network weighted throughput. Each terminal has one of 2 possible weights, which admit various practical interpretations. Earlier works of ours tell us that at least one terminal should operate at the highest available data rate, and that terminals not operating at this rate should operate at the same signal-to-interference ratio (SIR). This value is determined by the physical layer through the function that gives, in terms of the received SIR, the probability that a data packet is received correctly. In this work, we provide a more specific description of the optimal allocations. The key to the solution is an intersection point between an "X-shaped" graph arising from optimally conditions, and a "U-shaped" graph arising from the feasibility condition on power ratios. Our analysis is based on classical optimization theory, and should accommodate a wide variety of physical layer configurations.