Spectrum load smoothing for optimized spectrum utilization - rationale and algorithm

This paper aims at the mitigation of the destructive, mutual interference of coexisting, quality of service supporting wireless networks in a spectrum efficient way. The application of "waterfilling" from the information theory on the medium access of resource sharing wireless networks enables a decentralized coordinated, opportunistic usage of the spectrum and is in the following referred to as spectrum load smoothing (SLS). In using SLS, the competing wireless networks aim simultaneously at an equal overall smoothed utilization of the spectrum. In observing the past usage of the radio resource the wireless networks interact and redistribute their allocations of the spectrum under consideration of their individual quality of service requirements. Due to the principle of SLS these allocations are redistributed to less utilized or unallocated quantities of the transmission medium. Thereby, the individual quality of service requirements of the coexisting networks are considered. Further, the SLS allows an optimized usage of the available spectrum: an operation in radio spectrum, which was originally licensed for other communication systems is facilitated, as the SLS implies a search for unused spectrum as well as a release if it is needed again. This paper introduces the rationale of SLS and outlines in detail the algorithm which enables a cognitive medium access for multiple devices in a shared spectrum.