Fast Computation of Waterfilling Algorithms

The ever-increasing growth of the wireless applications and services reaffirms the\ud importance of the effective usage of radio resources. Waterfilling plays a crucial role\ud in effective use of resources, by optimizing power allocation to various available resources.\ud The term `waterfilling' was first introduced by Shannon and popularized\ud by Gallager to describe the `optimal transmit (power) mask as a function of the\ud channel and noise characteristics'. Waterfilling is hugely relevant, even today, as\ud various `versions' keep propping up in `almost' all fields of communications and signal\ud processing like Cognitive Radio, MIMO (Multiple-Input and Multiple-Output),\ud mmWave, OFDM (Orthogonal Frequency Division Multiplexing), OFDMA (Orthogonal\ud Frequency Division Multiple Access), DSL (Digital Subscriber Line), etc to name\ud a few