Patent ID: 9300373
Filing Date: 2016-03-29
CPC Classification: H04B,H04L

Claim Text:
1. A method, in a first node of a wireless communication system, for transmitting data to a second node, the method comprising, for a first transmission time interval: determining that first channel state information corresponding to the second node is likely to be unreliable for the first transmission time interval; and, responsive to said determining that first channel state information is likely to be unreliable, transmitting data and demodulation reference symbols to the second node over multiple transmit antennas in each of a plurality of groups of time-frequency resources during the first transmission time interval, using a precoding vector applied to the data and the demodulation reference symbols for each group of time-frequency resources, wherein the precoding vectors vary randomly or pseudo-randomly from each group of time-frequency resources to the next frequency-adjacent group or groups, or from each group of time-frequency resources to the next time-adjacent group or groups, or both; and, for a second transmission time interval: determining that second channel state information corresponding to the second node is likely to be reliable for the second transmission time interval; and, responsive to said determining that second channel state information is likely to be reliable, transmitting data and demodulation reference symbols to the second node over multiple transmit antennas in each of a plurality of groups of time-frequency resources during the second transmission time interval, using one or more precoding vectors that are based on the second channel state information.