Location Based Joint Spectrum Sensing and Radio Resource Allocation in Cognitive Radio Enabled LTE-U Systems

To support high speed transmission and traffic offloading from cellular networks, LTE-unlicensed (LTE-U) standard was proposed by 3GPP to enable cellular data transmission in unlicensed band. The primary challenge of LTE-U is to successfully coexist with the incumbent systems (e.g., WiFi networks) in the unlicensed bands, while still maintaining the quality-of-service (QoS) for LTE-A users. This paper proposes a new framework for implementing LTE-U standard based on deployed LTE-A infrastructure and cognitive radio (CR) technology to sense radio environment and construct a spectrum map, based on which the LTE-U system can perform joint power and channel allocation to maximize the overall system throughput. We introduce a spectrum map construction scheme and evaluate the Cramer-Rao bound of the scheme. It is shown that the original NP-hard joint power and channel allocation problem can be transformed into a linear programming problem for its solution. Simulation results verify that the proposed LTE-U scheme helps improve system throughput via access collision avoidance.