Energy-efficient dynamic point selection and scheduling method for intra-cell CoMP in LTE-A

In this paper, we propose a novel dynamic point selection (DPS) and user scheduling method for improving the energy efficiency in distributed antenna systems without cell edge spectral efficiency degradation. When DPS is used, each user is served by a single transmission point that can be dynamically switched. The proposed method decreases the power consumption by switching off inactive radio frequency (RF) chains and additionally reduces the interference by a static inter-cell agreement on which transmission points are simultaneously active. The performance of the method is evaluated by computer simulations in a system that accurately models the LTE-Advanced (LTE-A) intra-cell coordinated multi-point scenario 4. Based on the performance simulations, the proposed method achieves a significant energy efficiency gain over closed-loop spatial multiplexing applied on localized or distributed transmitting antennas. In general, the proposed method performs well when the load-independent RF power consumption is high in the active mode and low in the sleep mode. When the proportion of the load-independent RF power consumption to the total load-independent power consumption exceeds a certain limit, which is 22 % in the case of ten users in the 3-sector layout, the proposed method brings always energy efficiency gain even when RF chain micro sleeping cannot be implemented. The usability of the method is not dependent on the traffic load. The same approach can be applied to any distributed antenna system.