Abstract
Power control is an important topic in direct-sequence code division multiple access (DS-CDMA) cellular mobile radio systems, to achieve higher communication link quality and better system capacity under fading, noise, and interference. In order to track a desired signal-to-interference-plus-noise ratio (SINR) under transmission delay, multiple access interference (MAI), channel fading and noise, a robust state feedback control via a desired pole (eigenvalue) placement and an L1 optimal prediction is proposed for the power tracking control of CDMA systems. The L1 predictor is to predict the tracking error to compensate the effect of round-trip delay, such that the peak of prediction error due to the uncertainties of channel fading, interference, and noise is as small as possible. Then the optimal L1 predictor design problem is transformed to a suboptimal prediction problem by minimizing the upper bound of L1 norm of tracking error of dynamic system and solving the eigenvalue problem (EVP) under some linear matrix inequality (LMI) constraints. The Matlab LMI toolbox can be applied to efficiently solve the EVP via convex optimization to achieve a SINR tracking design via L1 optimal prediction scheme.