Dynamic spectrum management in wireless networks [Guest Editorial]

With the spectrum scarcity and underutilization of certain allocated bands, dynamic spectrum management (DSM) appears as an attractive solution. Novel techniques and technologies are needed to provide the necessary intelligence and adaptation for spectrum sharing and cooperation of multiple wireless networks. Under the so-called cognitive radio approach, environmentaware unlicensed wireless devices can share the spectrum with other licensed networks without degrading their performance and introducing unmanageable interference on the nodes of other networks. There are two ways for coexisting multiple networks to utilize the spectrum. First, the primary network, as the owner of the spectrum, makes a decision to share the spectrum with the secondary network based on a mutual agreement. Alternatively, the secondary network may access the spectrum opportunistically. The recent advances in a multiplicity of technologies involved, ranging from adaptive signal processing and spectral estimation techniques to power control and cooperative communications, have rendered this coexistence feasible. While some initial steps toward the implementation of DSM concepts have already been taken, there are still challenges that need to be tackled before their full potential can be achieved. This Special Issue aims to bring together certain recent work in the area of DSM and cognitive networks.