US 11,876,552 B2
Method for mitigating passive intermodulation and an apparatus therefor
Fanggang Wang, Beijing (CN); Haiying Cao, Beijing (CN); Yu Liu, Beijing (CN); Peng Liu, Beijing (CN); Vijay Venkateswaran, Västerås (SE); and Bo Ai, Beijing (CN)
Assigned to TELEFONAKTIEBOLAGET LM ERICSSON (PUBL), Stockholm (SE)
Appl. No. 17/794,232
Filed by Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
PCT Filed Feb. 4, 2020, PCT No. PCT/CN2020/074267
§ 371(c)(1), (2) Date Jul. 20, 2022,
PCT Pub. No. WO2021/155493, PCT Pub. Date Aug. 12, 2021.
Prior Publication US 2023/0071619 A1, Mar. 9, 2023
Int. Cl. H04B 1/525 (2015.01); H04L 1/00 (2006.01)
CPC H04B 1/525 (2013.01) [H04L 1/0054 (2013.01); H04L 1/0061 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for mitigating passive intermodulation, PIM, in a first network node, wherein said PIM is caused by radio signals transmitted from at least an adjacent network node, the method being performed by a control device, the method comprising the steps:
i) receiving at least an uplink, UL, radio signal comprising disturbance and desired signals and down-converting the received UL radio signal to a UL baseband signal, wherein the received UL baseband signal comprises detected information bits;
ii) applying a cyclic redundancy check, CRC, on the detected information bits of the received UL baseband signal, wherein
iii) in response to determining by the CRC that the UL baseband signal is detected correctly, directly output the detected information bits, and,
iv) in response to determining by the CRC that the UL baseband signal is incorrectly detected, determining a residual signal of the received UL baseband signal;
v) applying a blind signal identification scheme on the residual signal of the UL baseband signal to obtain an estimate for a modeled PIM signal; and
vi) subtracting the estimated modelled PIM signal from the received UL baseband signal as in step i) and updating the received UL baseband signal in an iterative process until CRC is detected correctly or until number of iterations exceeds a predetermined threshold.