US 12,381,684 B2
SRS layer and port estimation for uplink and downlink transmission
Raghavendra Madanahally Ramakrishna, Bangalore (IN); Ronak Bharatkumar Lalwala, Bangalore (IN); Vijayakumar Yalamalli, Bangalore (IN); and Vihang Kamble, Surrey (GB)
Assigned to Rakuten Symphony, Inc., Tokyo (JP)
Filed by Rakuten Symphony, Inc., Tokyo (JP)
Filed on Mar. 27, 2023, as Appl. No. 18/126,626.
Prior Publication US 2024/0333453 A1, Oct. 3, 2024
Int. Cl. H04L 5/00 (2006.01); H04B 17/336 (2015.01)
CPC H04L 5/0051 (2013.01) [H04B 17/336 (2015.01)] 17 Claims
OG exemplary drawing
 
1. A method of selecting layers and ports for Multiple-Input-Multiple-Output (MIMO) beamforming, the method comprising:
receiving a plurality of Sounding Reference Signals (SRSs) transmitted by a plurality of SRS ports, wherein each of the plurality of SRSs corresponds with a SRS port of a User Equipment (UE);
measuring a Signal-to-Noise Ratio (SNR) for each of the plurality of SRS ports;
estimating a wideband channel port correlation matrix across the plurality of SRS ports;
setting a correlation threshold;
setting a SNR threshold; and
selecting one or more SRS ports from the plurality of SRS ports that satisfy a condition of being equal to or less than the correlation threshold and equal to or greater than the SNR threshold, wherein a number of layers is selected such that the layers correspond with a total number of SRS ports that satisfy the condition of being equal to or less than the correlation threshold and equal to or greater than the SNR threshold,
wherein selecting the one or more SRS ports comprises:
initializing a set of SRS ports by selecting the SRS port with the highest SNR;
determining if a correlation between the selected SRS port and each other SRS port of the plurality of SRS ports satisfies the condition of being equal to or less than the correlation threshold and equal to or greater than the SNR threshold;
selecting a next SRS port;
determining if the correlation between the next selected SRS port and each other SRS port of the plurality of SRS ports satisfies the condition of being equal to or less than the correlation threshold and equal to or greater than the SNR threshold;
repeating the selecting a next SRS port and the determining for each SRS port of the plurality of SRS ports until all SRS ports of the plurality of SRS ports are tested against the condition; and
updating the set of SRS ports with all SRS ports that satisfy the condition of being equal to or less than the correlation threshold and equal to or greater than the SNR threshold.