Simultaneous operation of multiple collocated radios and the scanning problem

Simultaneous operation of multiple collocated radios refers to the capability of a wireless device to operate at the same time into several modes, standards and frequencies. For instance, most of the mobile phones are able and try to operate in multiple modes. Each wireless communication unit is called a radio interface. The software defined radio technology facilitates the integration and simultaneous operation of several radio interfaces in the same hardware device. Simultaneous operation produces interference and hardware conflicts, which can be addressed using a turn-based model. Each radio interface operates periodically for an interval of time. In this paper, the focus is on one radio interface that operates periodically for a short interval of time. The radio interface scans channels to uncover beacons periodically sent by transmitters. The goal of the scanning activity is to uncover the beacons within the shortest possible time. We call this the scanning problem. We model and compare four strategies to solve the scanning problem: sequential scanning, sliding-window scanning, pseudo-concurrent scanning and truly-concurrent scanning.