Patent ID: 11894898
Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 7:
8. A method in a wireless device, WD, the method comprising:
receiving a signal from a network node, the signal having N channel state information reference signals, CSI-RS, resources transmitted by a four-antenna dual polarization antenna array of a radio of the network node, the signal generated by the network node by applying N incremented phase rotations to one of the four antennas to produce N channel state information reference signal, CSI-RS, resources, N being an integer greater than 1, the N incremented phase rotations being obtained by multiplying a precoder codebook by a diagonal matrix whose diagonal elements are equal to one, except for one diagonal element corresponding to one of the four antennas and being equal to exp(j2πn/N), where n is an integer from zero to N−1;
determining a CSI-RS resource of the N CSI-RS resources resulting in a highest spectrum efficiency of all the N CSI-RS resources; and
transmitting to the network node a CSI resource indicator, CRI, indicating the determined CSI-RS resulting in the highest spectrum efficiency of all the N CSI-RS resources.