Patent ID: 9130615
Filing Date: 2015-09-08
Classification: H04B,H04L

Abstract:
1. A method of transmitting pilot reference signals utilized by a receiver for channel estimation in a Multiple-Input Multiple-Output (MIMO) communication system in which a transmitter utilizes a plurality of transmit antennas, the method comprising the steps of: spacing the plurality of transmit antennas such that spacing between adjacent antennas provides a spatial correlation coefficient greater than a threshold level; selecting by the transmitter, a selected subset of the plurality of transmit antennas for transmitting the pilot reference signals; and transmitting the pilot reference signals only from the selected subset of transmit antennas through a propagation environment to a receiver; wherein the selecting step includes selecting transmit antennas at an interval in the spatial domain depending on scattering characteristics of the propagation environment, wherein the interval between selected transmit antennas is greater than adjacent antennas, but still provides a density of transmitted pilot signals sufficient to enable the receiver to interpolate the channel over those antennas that do not transmit pilot reference signals.