Patent ID: 9408086
Filing Date: 2016-08-02
CPC Classification: H04B,H04L,H04W

Claim Text:
1. A channel state information feedback method of a mobile station in a massive Multiple-Input Multiple Output (MIMO) system, the method comprising: receiving N beams from a base station: estimating a channel vector comprising N, which is a non-negative integer value, channel coefficients of each N beams transmitted from the base station; comparing result values of a function having an input of the N channel coefficients to each other; selecting an index of a beam formed with a maximum value of the result values; selecting indices of beams, when result values of the beams are greater than or equal to a threshold value multiplied by the maximum value of the result value and a difference between phases of the channel coefficient of the beams and a phase of the beam formed with the maximum value of the result values is less than or equal to a phase threshold value: generating an active beam index set including the selected indices of beams; estimating channel state information on the active beam index set; and feeding back the channel state information and the active beam index set to the base station, and wherein the N beams are generated based on N beamforming vectors of size M by the base station, and the size M is associated with a number of transmit antennas of the base station.