Facing the challenge of meeting ever-increasing demand for wireless data, theindustry is striving to exploit large swaths of spectrum which anyone can usefor free without having to obtain a license. Major standards bodies arecurrently considering a proposal to retool and deploy Long Term Evolution (LTE)technologies in unlicensed bands below 6 GHz. This paper studies thefundamental questions of whether and how the unlicensed spectrum can be sharedby intrinsically strategic operators without suffering from the tragedy of thecommons. A class of general utility functions is considered. The spectrumsharing problem is formulated as a repeated game over a sequence of time slots.It is first shown that a simple static sharing scheme allows a given set ofoperators to reach a subgame perfect Nash equilibrium for mutually beneficialsharing. The question of how many operators will choose to enter the market isalso addressed by studying an entry game. A sharing scheme which allows dynamicspectrum borrowing and lending between operators is then proposed to addresstime-varying traffic and proved to achieve perfect Bayesian equilibrium.Numerical results show that the proposed dynamic sharing scheme outperformsstatic sharing, which in turn achieves much higher revenue than uncoordinatedfull-spectrum sharing. Implications of the results to the standardization anddeployment of LTE in unlicensed bands (LTE-U) are also discussed.
展开▼
