US 12,308,911 B2
Signal precoding
Fredrik Athley, Västra Frölunda (SE); Xinlin Zhang, Västra Frölunda (SE); and Mattias Frenne, Uppsala (SE)
Assigned to TELEFONAKTIEBOLAGET LM ERICSSON (PUBL), Stockholm (SE)
Appl. No. 18/270,446
Filed by Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
PCT Filed Nov. 18, 2021, PCT No. PCT/EP2021/082194
§ 371(c)(1), (2) Date Jun. 29, 2023,
PCT Pub. No. WO2022/144128, PCT Pub. Date Jul. 7, 2022.
Claims priority of provisional application 63/131,888, filed on Dec. 30, 2020.
Prior Publication US 2024/0063854 A1, Feb. 22, 2024
Int. Cl. H04B 7/0456 (2017.01); H04B 7/06 (2006.01)
CPC H04B 7/0456 (2013.01) [H04B 7/0626 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method for precoding a signal, the method comprising:
determining, based on uplink (UL) measurements, a spatial domain (SD) precoding vector and a frequency domain (FD) precoding vector for a downlink (DL) transmission of the signal;
applying the FD precoding vector to the signal over subcarriers for carrying the signal, thus producing a modified signal; and
producing a precoded signal (y) for transmission by applying the SD precoding vector to the modified signal to produce the precoded signal (y) for transmission, wherein the SD precoding vector is common for all said subcarriers in one symbol, wherein
applying the FD precoding vector to the signal comprises:
generating the conjugate of the FD precoding vector; and
calculating r=f*⊙r, where f* is the conjugate of the FD precoding vector, ⊙ denotes element-wise multiplication, r is the signal, and r is the modified signal, and
producing the precoded signal (y) for transmission comprises calculating: y=brT, where rT is the transpose of the modified signal, and b is the SD precoding vector, and
the method further comprises transmitting the precoded signal (y) using multiple antenna ports.