Adaptive power/rate allocation for minimum mean transmission delay in CDMA networks

We derive the optimum power and rate allocation rule for CDMA downlink networks, which minimizes mean transmission delay of the simultaneous users experiencing different channel gains under total transmission power and the required SIR constraints. The amount of reduction in average mean transmission delay by the proposed optimum allocation rule against the equal rate and equal power allocation schemes is also derived for the case when each user undergoes independent shadowing and path loss. It is shown that the proposed allocation rule not only achieves the minimum mean transmission delay but also minimizes the probability of the data rate being less than a tolerable threshold, against the equal rate or equal power allocation schemes.