Patent ID: 9025577
Filing Date: 2015-05-05
Classification: H04B,H04L,H04W

Abstract:
1. A wireless base station, comprising one or more controllers that: determine at least a part within any downlink subframe as a first resource for periodically transmitting downlink user data to a wireless terminal, and determine at least a part of an uplink part within a switch subframe or a part of an uplink subframe as a second resource for said wireless terminal to periodically transmit a first sounding reference signal; notify said wireless terminal of determined said second resource; estimate a state of a transmission path to said wireless terminal based on a second sounding reference signal included in uplink user data received from said wireless terminal after determination of said first resource and until reception of said first sounding reference signal from said wireless terminal, and estimate a state of a transmission path to said wireless terminal based on said first sounding reference signal after reception of said first sounding reference signal; and form directivity of a plurality of antennas based on estimated said state of the transmission path, and transmit said downlink user data through said first resource.