User-capacity maximization in synchronous CDMA subject to RMS-bandlimited signature waveforms

We consider the symbol-synchronous code-division multiple-access (CDMA) channel equipped with either a multiuser linear receiver or a multiuser decision-feedback receiver. The network, or user, capacity is defined to be the number of users that can be supported with available resources, such that every user achieves a certain quality of service (QoS). In this paper, the QoS threshold is given as a signal-to-interference ratio and the bandwidth is given as the root mean squared bandwidth of the received power spectral density of the users´ transmitted waveforms. Given the QoS threshold and constraints on bandwidth and the sum of the users´ received powers, we maximize user capacity for both the linear and decision-feedback receivers by optimally and jointly designing the users´ signature waveforms and power-control polices.