Node and method for generating beamformed for downlink communications

摘要

Example embodiments presented herein are directed towards an eNodeB, and method therein, for generating downlink communications in a multiple antenna system. The method comprises transmitting, to a number of user equipments, a plurality of reference signals, where each signal is beamformed in a distinct direction within at least one correlated domain (e.g., elevation and/or azimuth). The eNodeB receives at least one CSI report from a specific user equipment and determines a primary reference signal based on, for example, the at least one CSI report. The eNodeB may thereafter generate downlink communication signals for antenna element(s) and/or subelements of the multiple antenna system. The downlink communication signals are beamformed into a transmitting direction that aligns most closely with a beamforming direction of the at least one primary reference signal, as compared to any other beamforming direction of the reference signals.

主权项

1. A method, in an eNodeB, for generating downlink communications in a multiple antenna system, the eNodeB being comprised in a wireless communications network, the method comprising:
transmitting, to a plurality of user equipments, a plurality of Channel State Information (CSI) reference signals, each reference signal being beamformed into a distinct direction within at least one correlated domain of the multiple antenna system, wherein the at least one correlated domain is an elevation domain; receiving, from a specific user equipment, at least one Channel State Information (CSI) report for at least a subset of said plurality of CSI reference signals, wherein the CSI report comprises a Precoder Matrix Indicator, PMI, a Rank Indicator (RI) and at least one signal quality indicator (CQI); determining at least one candidate beamforming direction for the specific user equipment, wherein the at least one candidate beamforming direction is based, at least in part, on a signal quality assessment, which comprises a reference signal received power (RSRP), a reference signal received quality (RSRQ), and a received signal strength indicator (RSSI); determining, by the eNodeB, at least one primary reference signal among said plurality of reference signals based on the received at least one CSI report; and generating downlink communication signals for antenna element(s) and/or sub-elements of the multiple antenna system, wherein the downlink communication signals are beamformed into a transmitting direction that aligns most closely with a beamforming direction of the at least one primary reference signal determined by the eNodeB, as compared to any other beamforming direction of reference signals comprised in the subset of said plurality of CSI reference signals.