Methods, appatatus, and computer programs

Abstract

The present application is concerned with combining two different types of reference signals 502, 504, when performing channel estimation 500 at a UE. For example, CSI-RS and DMRS may be combined. A channel estimator receives quasi co-location (QCL) configuration information (2, Fig. 4). This includes an identification of at least one QCL-type and the set of resource elements (RE) over which a QCL relationship of that type applies. This could be achieved using a QC vector 506 or (QCL matrix) which indicates QCL-type per RE. The reference signals may each be superimposed pilots (SIP), superimposed on a downlink data channel which is to be estimated. For example the superimposed reference signals could be SI-CSI-RS and SI-DMRS. [Fig. 5 with abstract]