APPARATUS AND MEHOD FOR HIERARCHICAL CHANNEL SOUNDING AND CHANNEL STATE INFORMATION FEEDBACK IN MASSIVE MULTIPLE INPUT MULTIPLE OUTPLE SYSTEMS

摘要

PURPOSE: An apparatus for hierarchical channel sounding and channel state information (CSI) feedback in a massive multiple input multiple output (MIMO) system and a method thereof are provided to determine time, frequency and space processing technique for communication between a base station and at least one mobile station. CONSTITUTION: A mobile station (MS) receives at least one sector-level reference signal and a number of synchronous signals applied with different transmission space processing techniques, from at least one base station (602). The MS determines long-term CSI by using the synchronous signals and the sector-level reference signals. The MS determines at least one preferred slice in a sector for communication between the at least one base station and the MS, on the basis of the given CSI (603). The MS transmits a signal indicating the at least one preferred slice to the at least one base station. [Reference numerals] (601) Base station transmits multiple synchronous signals from multiple slices; (602) Mobile station receives multiple synchronous signals from multiple slices; (603) Mobile station determines at least one slice as a favorite one; (604) Mobile station provides the base station with a feedback indicating its determination of the at least one favorite slice; (605) Base station receives mobile station's feedback indicating mobile station's determination of the at least one favorite slice; (606) Base station and the mobile device have negotiations to select at least one actual slice to be activated for the base station and a CSI feedback code book for the base station is selected based on the base station's feedback and the selected at least one activated slice; (607) Base station receives a slice-level CSI-RS or a CRS; (608) Mobile station receives a slice-level CSI-RS or a CRS; (609) Mobile station transmits a CSI feedback at the selected slice using the selected CSI feedback code book; (610) Base station receives the mobile station's CSI feedback; (611) Base station transmits an scheduling approval and data packets regarding the mobile station's feedback; (612) Mobile station receives the scheduling approval and the data packets; (AA) Base station side action; (BB) Mobile station side action