Waterfilling is known as solution to the rate maximization problem with sum-power constraint in a multi-channel communication environment. It has been extended to the iterative waterfilling (IWF) algorithm for multi-channel interference scenarios, where each link repeatedly adapts its power allocation according to the waterfilling solution. A less known fact is that the solution to sum-power minimization with minimum rate constraint also is a waterfilling solution, yet with different water level. Similar to conventional, rate-maximizing waterfilling, an iterative power minimization waterfilling (P-IWF) algorithm can be defined. In this poster, we present basic properties of this new type of waterfilling. The key result is that P-IWF can be interpreted as fixed point algorithm of a multi-channel, standard interference function. From this, convergence properties can directly be deduced.
