Spectrum sharing LTE-advanced small cell systems

Cellular systems are designed such that a certain amount of radio spectrum is allocated for their exclusive use to ensure that interference within these systems is tightly controlled. For competitive reasons, spectrum is divided between operators despite the resulting inefficiency in the overall spectrum utilization. For systems with relatively large cells and significant number of users per cell the loss in efficiency is modest. However, losses can become very large as cells become smaller. This paper presents a cooperative spectrum access framework that enables spectrum sharing between small cells that are being deployed by different operators. Primary spectrum owning operators broadcast their spectrum occupancy information to allow small cells of other operators to access their spectrum as secondary users. LTE-Advanced systems employing small cells are considered. Simulations show that the proposed spectrum access framework enables small cells to achieve substantial performance gains without affecting the primary spectrum owning operator even when the small cell deployment density varies significantly between operators.