Asynchronous Iterative Water-filling for Gaussian Frequency-Selective Interference Channels: A Unified Framework

In this paper we propose a unified framework, based on a new distributed algorithm to compute the Nash equilibrium point of the power allocation game in a frequency-selective multiuser interference channel. The proposed scheme is based on a totally asynchronous updating of the power allocation from the users, where some users may change their power allocation more frequently than others and, furthermore, they are allowed to use also outdated version of the interference. The proposed algorithm contains as special cases the well-known iterative water-filling algorithm, either sequential or simultaneous. Our main contribution is then to provide a unified set of sufficient conditions under which all these algorithms are guaranteed to convergence to the unique Nash equilibrium of the game. These conditions enlarge those existing in the literature for the convergence of the sequential iterative water-filling algorithm.