Search

EP-4187996-B1 - PASSIVE INTER-MODULATION SOURCE POSITIONING METHOD AND APPARATUS

EP4187996B1EP 4187996 B1EP4187996 B1EP 4187996B1EP-4187996-B1

Inventors

  • YANG, ZHI
  • HUO, QIANG
  • WANG, Jinglun
  • CHEN, XI
  • ZOU, ZHIQIANG

Dates

Publication Date
20260506
Application Date
20210604

Claims (12)

  1. A passive intermodulation, PIM, source positioning method, wherein the method comprises: sequentially performing (S310), by a network device, a scanning process on each of a plurality of scanning spots by using the following steps: sending a plurality of downlink signals with different frequencies for a first scanning spot by using a transmit antenna, and receiving an uplink PIM signal for the first scanning spot by using a receive antenna, wherein the first scanning spot is any one of the plurality of scanning spots, and the uplink PIM signal is generated by excitation by any at least two of the plurality of downlink signals, wherein the network device divides a spatial area in which scanning is to be performed to detect a PIM source into I grids, where each grid is represented by one scanning spot, and I is a positive integer, indicating a quantity of scanning spots; and determining (S310), by the network device, the PIM source from the plurality of scanning spots based on uplink PIM signals respectively corresponding to the plurality of scanning spots, wherein before sending, by the network device, the plurality of downlink signals for the first scanning spot by using the transmit antenna, the method further comprises: performing, by the network device, precoding processing on at least one of the plurality of downlink signals based on at least one precoding matrix of the first scanning spot, wherein the precoding matrix of the first scanning spot comprises any one of the following: a complex conjugate matrix of a first electric field matrix of the first scanning spot, and/or a normalized matrix of the complex conjugate matrix of the first electric field matrix of the first scanning spot; a complex conjugate matrix of at least one spatial component of the first electric field matrix of the first scanning spot, and/or a normalized matrix of the complex conjugate matrix of the at least one spatial component of the first electric field matrix of the first scanning spot; and a complex conjugate matrix of at least one eigenvector obtained through singular value decomposition, SVD, by the first electric field matrix of the first scanning spot, wherein the first electric field matrix of the first scanning spot is obtained based on an antenna electromagnetic field model and a downlink configuration parameter.
  2. The method according to claim 1, wherein the determining, by the network device, a PIM source from the plurality of scanning spots based on uplink PIM signals respectively corresponding to the plurality of scanning spots comprises: determining, by the network device by using the following steps, first power values respectively corresponding to the plurality of scanning spots: determining, based on a sum of receive powers of a plurality of receive antennas in each scanning process on the first scanning spot, an uplink PIM signal receive power corresponding to the at least one precoding matrix; and determining, based on the uplink PIM signal receive power obtained in at least one scanning process on the first scanning spot, a first power value corresponding to the first scanning spot; determining, by the network device from the plurality of scanning spots, at least one target scanning spot whose first power value meets a first condition; and determining, by the network device, the target scanning spot as the PIM source.
  3. The method according to claim 2, wherein the first power value is: a maximum value of the uplink PIM signal receive power corresponding to the at least one scanning process on the first scanning spot; or an average value of the uplink PIM signal receive power corresponding to the at least one scanning process on the first scanning spot.
  4. The method according to claim 1, wherein there are a plurality of receive antennas, and the determining, by the network device, a PIM source from the plurality of scanning spots based on uplink PIM signals respectively corresponding to the plurality of scanning spots comprises: determining, by the network device by using the following steps, first power values respectively corresponding to the plurality of scanning spots: performing, in each scanning process on the first scanning spot based on a weight matrix of the first scanning spot, weighted summation processing on uplink PIM signals received by the plurality of receive antennas, to obtain a first signal, and determining a power of the first signal; and determining, based on the power of the first signal obtained in at least one scanning process on the first scanning spot, a first power value corresponding to the first scanning spot; determining, by the network device from the plurality of scanning spots, at least one target scanning spot whose first power value meets a first condition; and determining, by the network device, the target scanning spot as the PIM source.
  5. The method according to claim 4, wherein a weight matrix of the first scanning spot comprises any one of the following: a complex conjugate matrix of a second electric field matrix of the first scanning spot, and/or a normalized matrix of the complex conjugate matrix of the second electric field matrix of the first scanning spot; a complex conjugate matrix of at least one spatial component of the second electric field matrix of the first scanning spot, and/or a normalized matrix of the complex conjugate matrix of the at least one spatial component of the second electric field matrix of the first scanning spot; and a complex conjugate matrix of at least one eigenvector obtained through singular value decomposition, SVD, by the second electric field matrix of the first scanning spot, wherein the second electric field matrix of the first scanning spot is obtained based on an antenna electromagnetic field model and an uplink configuration parameter.
  6. The method according to claim 4 or 5, wherein the first power value is: a maximum power of the first signal corresponding to the at least one scanning process on the first scanning spot; or an average power of the first signal corresponding to the at least one scanning process on the first scanning spot.
  7. The method according to any one of claims 2 to 6, wherein each scanning spot corresponds to one first power value, and the first condition comprises: the first power value is a maximum value, and the first power value is greater than or equal to a set first threshold; and/or the first power value belongs to a first area in a power distribution image, wherein the power distribution image is obtained based on the first power values of the plurality of scanning spots, and the first area is an area whose power value is greater than the first threshold.
  8. The method according to any one of claims 1 to 7, wherein after the determining, by the network device, a PIM source from the plurality of scanning spots, the method further comprises: performing, by the network device, the following steps for a second scanning spot that is in the plurality of scanning spots and that is determined as the PIM source: recording location information of the second scanning spot into a PIM source location set, and obtaining, based on the second scanning spot, downlink interference channel information from the transmit antenna to the PIM source and/or uplink interference channel information from the PIM source to the receive antenna.
  9. An apparatus, wherein the apparatus is configured to perform the method according to any one of claims 1 to 8.
  10. A computer readable storage medium comprising an instruction, wherein which, when executed by a computer device, cause the computer device to perform the method according to any one of claims 1 to 8.
  11. A computer program product, comprising an instruction, wherein which, when executed by a computer device, cause the computer device to perform the method according to any one of claims 1 to 8.
  12. A chip system including a processor coupled to a memory and the memory configured to store a program or instructions, wherein the program or the instructions, which, when being executed by the processor, enable the chip system to implement the method according to any one of claims 1 to 8.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS TECHNICAL FIELD This application relates to the field of wireless communications technologies, and in particular, to a passive inter-modulation source positioning method and an apparatus, a computer readable storage medium, a computer program product and a chip system. BACKGROUND With the development of wireless communication systems, bandwidth and a quantity of antennas are increasing, and passive intermodulation (Passive InterModulation, PIM) interference becomes an important factor that limits a system capacity. In a wireless communication system, passive inter-modulation refers to an inter-modulation effect caused by non-linearity of passive components, such as connectors, feeders, antennas, and filters, when the components work in a condition of high-power signals on a plurality of frequencies. When downlink transmit signals on two or more frequencies hit an inter-modulation source in an external environment, a PIM signal on a new frequency is generated and reflected back to a receive end of the system. If the frequency of the PIM signal falls within a receive frequency range of a receive antenna, the receive antenna receives the PIM signal. The PIM signal causes interference to an uplink received signal. Consequently, quality of the uplink received signal deteriorates, and a system capacity is reduced or an available frequency band range of the system is reduced. Passive inter-modulation is a common phenomenon in communication systems. A level of inter-modulation is related to a manufacturing process, materials, a structure design, and an installation method of components, and is difficult to control. In addition, passive inter-modulation has time validity. To be specific, after a passive component (such as a duplexer or an antenna) is installed and used, an internal structure of the passive component changes due to factors such as thermal expansion and contraction, surface air oxidation, contamination, and looseness. Consequently, inter-modulation indicators gradually deteriorate. Therefore, it is difficult to ensure the solution of the problem of inter-modulation of passive components in an engineering manner with limited costs by improving the manufacturing process and standardizing the installation method. Conventional PIM source positioning depends on an external device. However, due to a limitation of a working mechanism of the external device, an application scope is limited. For example, a solution of positioning a PIM source by using an external device in a near field scanning method is applicable only to a PIM source in an open structure, such as an antenna or a microstrip, and is not applicable to a PIM source in a closed structure, such as a cable or a cavity filter. For another example, a solution of positioning a PIM source by using a sound wave or ultrasonic wave scanning device in a vibration modulation method is applicable only to a mechanical PIM source (mechanical PIM source) such as a ferrite fragment or a metal fragment, and is not applicable to a non-mechanical PIM source such as a defective solder joint. For a specific PIM source, a sound wave frequency further needs to be tested, or a sound wave frequency needs to be traversed within a specific range. In addition, the external device may also become a new PIM source. Because the problem of passive inter-modulation is inevitable in communication systems, how to accurately, quickly, and cost-effectively find a passive inter-modulation source without relying on an external device is an urgent problem to be resolved. US 2018/359048 A1 discloses a method for link adaptation that accounts for passive intermodulation, PIM, at a network node of a wireless communication system, where the network node has a first transmitter configured to generate first transmissions at a set of transmission frequencies at at least one antenna and has a receiver configured to receive signals at a set of receive frequencies. The method includes: determining, based on at least one transmission frequency of the set of transmission frequencies at at least one antenna, a PIM power spectral density (PSD) versus the set of receive frequencies; and performing link adaptation based on the PIM PSD versus the set of receive frequencies. Performing the link adaptation includes choosing at least one transmission parameter of a second transmitter scheduled to transmit on a frequency among the set of receive frequencies. US2015/358144 A1 discloses a method for detecting intermodulation in broadband communication affecting receiver sensitivity. The method includes: transmitting, at a base station, a first signal at a first centre frequency and a second signal at a second centre frequency with a predetermined transmit power; capturing, at the base station, received signal at a reception frequency; obtaining, at the base station, a delay between the transmitted signal and a passive intermodulation caused received signal. SUMMARY The