A Generic Approach to QoS-Based Transceiver Optimization

We propose a generic framework for jointly optimizing the transmit power allocation and the adaptive receive strategies in a multiuser network with individual quality-of-service (QoS) requirements. The QoS is assumed to be a one-to-one mapping of the signal-to-interference-plus-noise ratio (SINR). The feasibility of certain target QoS depends on the mutual interference and on a given sum-power constraint. This coupling can be modeled by interference functions, which determine how the transmit powers cause interference to the individual users. We show fundamental properties, like continuity and feasibility for the most general case when the functions are defined by axioms. Additional properties are shown for the case when the interference functions are based on a parameter-dependent coupling matrix, which allows to apply techniques from the theory of nonnegative matrices. We derive a class of iterative algorithms, which exploit the matrix structure. The proposed iteration converges monotonically to the global optimum. Starting from the same initialization, it is better than the known fixed-point iteration. It achieves arbitrary QoS values within the QoS-feasible region.