US 11,706,054 B2
Methods, distributed base station system, remote radio unit and base band unit system for handling uplink signals
Yezi Huang, Täby (SE); Miguel Berg, Sollentuna (SE); and Chenguang Lu, Sollentuna (SE)
Assigned to Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
Appl. No. 17/608,601
Filed by Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
PCT Filed May 3, 2019, PCT No. PCT/SE2019/050395
§ 371(c)(1), (2) Date Nov. 3, 2021,
PCT Pub. No. WO2020/226538, PCT Pub. Date Nov. 12, 2020.
Prior Publication US 2022/0217018 A1, Jul. 7, 2022
Int. Cl. H04L 25/02 (2006.01); H04B 17/345 (2015.01); H04B 7/06 (2006.01)
CPC H04L 25/0224 (2013.01) [H04B 7/0617 (2013.01); H04B 17/345 (2015.01); H04L 25/021 (2013.01); H04L 25/0204 (2013.01); H04L 25/0242 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method performed by a Remote Radio Unit, RRU, of a distributed base station system of a wireless communication network, the distributed base station system further comprising a Base Band Unit, BBU, connected to the RRU over a fronthaul link, the RRU being connected to N antennas, the method comprising:
obtaining uplink signals y as received at the N antennas from a number of UEs wirelessly connected to the RRU, the uplink signals comprising K user-layer signals overlaid with J interference signals and noise;
obtaining a channel estimation matrix Ĥ of wireless communication channels H between the number UEs and the N antennas from reference signals yref,l as received at the N antennas from the number of UEs;
determining an interference covariance estimation matrix R based on the obtained channel estimation matrix Ĥ and on other channel information different from the channel estimation matrix;
sending information on the channel estimation matrix Ĥ and on the interference covariance estimation matrix R over the fronthaul link to the BBU;
determining intermediate signals y, based on the uplink signals y, the channel estimation matrix Ĥ and the interference covariance estimation matrix R, the intermediate signals having K+L components, where (K+L) is smaller than N, and L is larger than zero and L is a number of fronthaul streams transported via the fronthaul link additional to K, and
sending to the BBU over the fronthaul link, the determined intermediate signals y.