Joint Signal Design and Power Control for CDMA with Decision-Feedback Receivers and Asymmetric QoS Constraints

摘要

A synchronous code-division multiple-access (CDMA) channel is considered for which power control is available. Each of the users is assigned a quality-of-service (QoS) threshold that is measured in terms of a signal-to-interference ratio (SIR), and to cover the situation of multiple classes of users, these are allowed to be unequal to each other. The receiver is taken to be of the nonlinear decision-feedback type in which the users are successively detected. When the users' signature sequences and their received powers are fixed, such a decision-feedback receiver can be designed to be user-wise SIR maximizing. Given a constraint on the total power (i. e., the sum of the users' received powers), we minimize the required processing gain over all sets of signature sequences and power-control policies that allow the users to meet their respective QoS constraints. Conversely, this can be viewed as fixing the processing gain and then minimizing the required total power over all sets of signature sequences and power-control polices that deliver the required QoS constraints.