Patent ID: 8923203

Claim:
A method of operating a network element in a wireless communications network, the method comprising: identifying, by at least a network element, a channel state information reference signal (CSI-RS) that is orthogonal to CSI-RSs transmitted by each of a first network cell and a set of neighbor cells that interfere with the first network cell, wherein the first network cell is a macro cell and has a coverage containing a coverage of a second network cell, wherein the network element is associated with the second network cell; and transmitting, by the network element, the identified CSI-RS, wherein the set of interfering neighbor cells is a subset of a CSI-RS network cell group, and the CSI-RS transmitted by the network element is the same as a CSI-RS transmitted by a network cell that is a member of the CSI-RS network cell group, but not a member of the set of interfering neighbor cells.