Strategies for distributed QoS support in radio spectrum sharing

Spectrum sharing in unlicensed bands is expected to become an increasingly significant research problem. With the proliferation of IEEE 802.11 wireless local area networks, and with other future radio systems using the unlicensed bands, spectral coexistence of dissimilar radio systems will have to be addressed. Coexistence can be achieved with the help of spectrum etiquette, or alternatively by implementing new communication protocols and defining common spectrum coordination channels. We investigate how two independent wireless networks may share spectrum without direct coordination and information exchange. We start by illustrating our previously introduced stage-based game model of such scenarios. The application of game models allows us to analyze the problem as a player competition; within radio resource sharing games, payoff-maximizing players represent wireless networks. Decisions that players repeatedly have to make are about when, and how often, to attempt medium access. We use an established notation to describe multi-stage strategies that determine a player´s decision-making. Should radio networks cooperate or should competing radio networks ignore the presence of other radio networks? What is the expected outcome in a repeated interaction? The paper shows that traffic requirements imposed by services and applications determine the selected strategies, which pursue cooperation or ignore other radio systems.