Cross-layer carrier selection and power control for LTE-A uplink with Carrier Aggregation

Long Term Evolution-Advanced (LTE-A) standard with Carrier Aggregation (CA) is emerging as a promising technology for 4G mobile communication systems to fulfill tremendous growth of high-data-rate demand. However, in LTE-A systems with CA, the uplink Radio Resource Management (RRM) performance is greatly limited by the insufficient user transmission power and the infamous power offset effects. In this paper, we design a cross-layer carrier selection and power control strategy for LTE-A uplink with CA to improve the average user throughput, while dealing with the above limitations. Specifically, we first propose a novel estimation method to effectively predict the average bandwidth that a newly admitted user can obtain from each carrier. The time-variability of carrier load conditions is carefully taken into account. Then, an optimal carrier subset and power allocation values are determined for each arrived user to improve the average user throughput by solving a user-power-utilization maximization problem, with considering the user power constraints and offset effects. Extensive simulations validate the effectiveness of the estimation method and demonstrate that the proposed cross-layer strategy can achieve higher average user throughput compared with the existing approach.