Simplified passive cross modulation detection and elimination method and system

Abstract

The invention discloses a simplified passive cross modulation detection and elimination method and system, and belongs to the field of mobile communication.The simplified passive cross modulation detection and elimination method comprises the steps that passive cross modulation signals are detected, when the passive cross modulation signals exist, the power of sending signals and the power of receiving signals are calculated, and the carrier frequency band of the sending signals is detected; and then component construction and component frequency shifting are carried out on the passive intermodulation signal, and a gain value between a sending signal and a receiving signal is calculated, so that elimination of the passive intermodulation signal is completed, and the technical problem that in the prior art, a passive intermodulation signal elimination module is normally open, so that system power consumption is too large is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of mobile communications, and in particular relates to a simplified passive intermodulation detection and elimination method and system. Background Art

[0002] Passive intermodulation (PIM), abbreviated as PIM for Passive Intermodulation, is distortion caused by passive components, such as third-order and fifth-order intermodulation. These distortions often exist in passive components such as antennas, couplers, and other related hardware. In FDD systems, these distortions significantly increase the noise floor of the RX receiver, significantly reducing RX sensitivity. Therefore, a method is needed to identify this passive intermodulation and then use appropriate methods to eliminate it, thereby improving RX sensitivity. Furthermore, commonly used PIM elimination methods often require matrix inversion to calculate distortion coefficients, but this calculation consumes a significant amount of resources due to the matrix inversion operation. Therefore, a PIM elimination method with a lower computational effort is needed. PS stands for Power Saving, and PIMC stands for Passive InterModulation Cancel.

[0003] Existing technologies don't include any PIM detection solutions, requiring the PIMC module to be constantly powered on, which consumes significant power. Furthermore, existing technologies require matrix inversion operations, which consume significant software and hardware resources. Therefore, a simplified, low-power passive intermodulation detection and elimination method is needed. Summary of the Invention

[0004] In view of the problem of excessive system consumption in the prior art, the present invention proposes a simplified passive intermodulation detection and elimination method, comprising the following steps: S1: Detect whether there is a passive intermodulation signal; S2: construct the components of the passive intermodulation signal; S3: Transmit the passive intermodulation signal component of the transmitted signal to the frequency point corresponding to the received signal; S4: Calculate the delay between the sending signal and the receiving signal; S5: Calculate the gain between the transmitted signal and the received signal; S6: Calculate the value of the received signal after eliminating the passive intermodulation signal, thereby completing the elimination of the passive intermodulation signal.

[0005] Preferably, step S1 also includes the following process: A1: First calculate the power of the transmitted signal; A2: Calculate the power of the received signal again; A3: Finally, determine whether the carrier frequency band of the transmitted signal will cause the passive intermodulation signal component to fall within the received signal, and complete the detection of the passive intermodulation signal.

[0006] Preferably, in the A1 process, the power calculation method of the transmitted signal is as follows: Let the transmitted signal be TX(n), where n represents the transmitted data at the nth moment, and RX(n) represents the received signal. Then the power of the transmitted signal is: where N represents the total sampling time, real represents taking the real part, and imag represents taking the imaginary part; If where thr1 represents threshold 1, then Otherwise .

[0007] Preferably, in the A2 process, the power calculation method of the received signal is as follows: Let the power of the received signal be RXP, then there is: If where thr2 represents threshold 2, then Otherwise .

[0008] Preferably, the judgment method in the A3 process is as follows: Let the carrier frequencies of the transmitted signal be from low to high as , … , where T represents the number of transmitted carriers, and the bandwidth of the tth (0 < t < T + 1) carrier is BW; the transmitted frequency band of the transmitted signal is to , and the received frequency band of the received signal is to ; If Or Then Otherwise If , , If both are 1, it means that a passive intermodulation signal is detected and counted into the passive intermodulation modulation module. Otherwise, it is considered that no passive intermodulation signal is detected and the passive intermodulation modulation module is turned off. entp represents the judgment result of the transmit power, enrp represents the detection result of the receive power, and enft represents the final judgment result of the transmit carrier.

[0009] Preferably, the process of constructing the components of the passive intermodulation signal in step S2 is as follows: let the components of the input signal be , then we have: in Indicates the amplitude value of the signal.

[0010] Preferably, in step S3, the process of the passive intermodulation signal and the received signal corresponding to each other is as follows: Where exp represents the exponential operation of the natural logarithm, Represents pi 3.1415926… an infinite non-repeating decimal.

[0011] Preferably, in step S4, the delay value calculation process between the sending signal and the receiving signal is as follows: Where conv represents convolution calculation, and arg represents the independent variable; Then Align with the received signal to get the delay result. The signal after the passive intermodulation signal is frequency-shifted, ; In step S5, the gain value calculation process between the transmitted signal and the received signal is as follows: , gain is the gain between the received signal and the transmitted signal.

[0012] Preferably, in step S6, the numerical calculation process of the received signal after the passive intermodulation signal is eliminated is as follows: Let the result after RX eliminates PIM be , that is, the result after completing the elimination of the passive intermodulation signal is as follows: .

[0013] A simplified passive intermodulation detection and elimination system includes the following modules: a passive intermodulation signal detection module, a signal component construction module, a signal component frequency shifting module, a delay numerical calculation module, a gain numerical calculation module, and a passive intermodulation elimination module; Passive intermodulation signal detection module: first calculate the power of the transmitted signal, then calculate the power of the received signal, Finally, it is detected whether the carrier frequency band of the transmitted signal will cause the passive intermodulation signal component to fall into the received signal, thereby completing the detection of the passive intermodulation signal; Signal component construction module: constructs the components of the received passive intermodulation signal; Signal component frequency shifting module: transfers the passive intermodulation signal component of the transmitted signal to the frequency point corresponding to the received signal; Delay value calculation module: calculates the delay value between the sending signal and the receiving signal; Gain value calculation module: calculates the gain value between the transmitted signal and the received signal; Passive intermodulation elimination module: calculates the value of the received signal after the passive intermodulation signal is eliminated, thereby completing the elimination of the passive intermodulation signal.

[0014] Compared with the prior art, the technical solution of the present invention has the following advantages / benefits: 1. The present invention detects the passive intermodulation signal and determines whether to turn on the passive intermodulation signal elimination module based on the detection result. Compared with the prior art passive intermodulation signal elimination module that is always turned on, it saves a lot of system resources and reduces system power consumption.

[0015] 2. The present invention obtains distortion coefficients by constructing components of passive intermodulation signals, without the need for matrix inversion, thereby reducing resource overhead in the passive intermodulation signal elimination step.

[0016] 3. The present invention completes the calculation of the distortion coefficient by calculating the gain value, eliminates the coefficient update process, reduces the matrix inversion process, greatly reduces the resources consumed by the system, and enhances the energy efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 The present invention is a simplified passive intermodulation detection and elimination method flow chart.

[0019] Figure 2 It is a schematic diagram of a simplified passive intermodulation detection and elimination system of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0021] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it may not be further defined or explained in subsequent drawings.

[0022] Example 1: Passive intermodulation is abbreviated as PIM in English, which is a distortion from passive components, such as third-order intermodulation, fifth-order intermodulation, etc. PIM often exists in passive components, such as antennas, couplers and other related hardware. These distortions will cause the noise floor of the receiver receiving the signal in the FDD system to increase significantly, resulting in a significant reduction in the sensitivity of the received signal. In addition, there are various distortions in various passive components, and it is necessary to use appropriate methods to eliminate this passive intermodulation and improve the sensitivity of the received signal. In addition, the elimination methods commonly used in the prior art often involve matrix inversion to calculate the distortion coefficient, but this calculation often consumes a lot of resources due to the matrix inversion operation. Therefore, it is necessary to consider a passive intermodulation elimination method that can reduce the amount of calculation and identify passive intermodulation signals. The present invention provides a simplified passive intermodulation detection and elimination method, comprising the following steps: S1: Detect whether there is a passive intermodulation signal; S2: When a passive intermodulation signal is detected in step S1, components of the passive intermodulation signal are constructed; S3: Transmit the passive intermodulation signal component of the transmitted signal to the frequency point corresponding to the received signal; S4: Calculate the delay between the sending signal and the receiving signal; S5: Calculate the gain between the transmitted signal and the received signal; S6: Calculate the value of the received signal after eliminating the passive intermodulation signal, thereby completing the elimination of the passive intermodulation signal.

[0023] Since the passive intermodulation signals mainly eliminated in this patent come from the PIM components leaked from the TX antenna coupler into the RX received signals, it is necessary to detect the power of the TX.

[0024] In step S1, the following processes are also included: A1: First, calculate the power of the transmitted signal; A2: Then, calculate the power of the received signal; A3: Finally, determine whether the carrier frequency band of the transmitted signal will cause passive intermodulation signal components to fall into the received signal, and complete the detection of passive intermodulation signals.

[0025] In process A1, the power calculation method of the transmitted signal is as follows: Let the transmitted signal be TX(n), where n represents the transmitted data at the nth moment, and RX(n) represents the received signal. Then the power of the transmitted signal is: where N represents the total sampling time, real represents taking the real part, and imag represents taking the imaginary part; If where thr1 represents threshold 1, then Otherwise .

[0026] In process A2, the power calculation method of the received signal is as follows: Let the power of the received signal be RXP, then there is: If where thr2 represents threshold 2, then Otherwise .

[0027] The judgment method in process A3 is as follows: Let the carrier frequencies of the transmitted signal be from low to high as , … , where T represents the number of transmitted carriers, and the bandwidth of the tth (0 < t < T + 1) carrier is BW; the transmitted frequency band of the transmitted signal is to , and the received frequency band of the received signal is ​​​​​ or So otherwise if , , If both are 1, it means that a passive intermodulation signal is detected and counted into the passive intermodulation modulation module. Otherwise, it is considered that no passive intermodulation signal is detected and the passive intermodulation modulation module is turned off. entp represents the judgment result of the transmit power, enrp represents the detection result of the receive power, and enft represents the final judgment result of the transmit carrier.

[0028] Step S2 constructs the components of the passive intermodulation signal as follows: Let the components of the input signal be , then we have: in Indicates the amplitude value of the signal.

[0029] In step S3, the process of the passive intermodulation signal corresponding to the received signal is as follows: Where exp represents the exponential operation of the natural logarithm, Represents pi 3.1415926… an infinite non-repeating decimal.

[0030] In step S4, the delay between the transmitted signal and the received signal is calculated as follows: Where conv represents convolution calculation, and arg represents the independent variable; Then Align with the received signal to get the delay result. The signal after the passive intermodulation signal is frequency-shifted, ; In step S5, the gain value calculation process between the transmitted signal and the received signal is as follows: , gain is the gain between the received signal and the transmitted signal.

[0031] Preferably, in step S6, the numerical calculation process of the received signal after the passive intermodulation signal is eliminated is as follows: Let the result after RX eliminates PIM be , that is, the result after completing the elimination of the passive intermodulation signal is as follows: .

[0032] Example 2: like Figure 2 As shown, the present invention also provides a simplified passive intermodulation detection and elimination system, comprising the following modules: a passive intermodulation signal detection module, a signal component construction module, a signal component frequency shifting module, a delay numerical calculation module, a gain numerical calculation module, and a passive intermodulation elimination module; Passive intermodulation signal detection module: first calculate the power of the transmitted signal, then calculate the power of the received signal, Finally, it is detected whether the carrier frequency band of the transmitted signal will cause the passive intermodulation signal component to fall into the received signal, thereby completing the detection of the passive intermodulation signal; Signal component construction module: constructs the components of the received passive intermodulation signal; Signal component frequency shifting module: transfers the passive intermodulation signal component of the transmitted signal to the frequency point corresponding to the received signal; Delay value calculation module: calculates the delay value between the sending signal and the receiving signal; Gain value calculation module: calculates the gain value between the transmitted signal and the received signal; Passive intermodulation elimination module: calculates the value of the received signal after the passive intermodulation signal is eliminated, thereby completing the elimination of the passive intermodulation signal.

[0033] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A simplified passive intermodulation detection and elimination method, characterized in that: The following steps are involved: S1: Detect whether there is passive intermodulation signal; S2: construct the components of the passive intermodulation signal; S3: Transmit the passive intermodulation signal component in the transmit signal to the frequency point corresponding to the receive signal; S4: Calculate the delay between the sending signal and the receiving signal; S5: Calculate the gain between the transmitted signal and the received signal; S6: Calculate the value of the received signal after eliminating the passive intermodulation signal, thereby completing the elimination of the passive intermodulation signal.

2. A simplified passive intermodulation detection and elimination method according to claim 1, characterized in that: The S1 step also includes the following process: A1: First calculate the power of the transmitted signal; A2: Calculate the power of the received signal again; A3: Finally, determine whether the carrier frequency band of the transmitted signal will cause the passive intermodulation signal component to fall into the received signal, and complete the detection of the passive intermodulation signal.

3. A simplified passive intermodulation detection and elimination method according to claim 2, characterized in that: In the A1 process, the power calculation method of the transmitted signal is as follows: let the transmitted signal be TX(n), where n represents the transmitted data at the nth moment, and RX(n) represents the received signal, then the power of the transmitted signal is: Where N represents the total sampling time, real represents the Realistic department, imag represents Find the imaginary part; like Where thr1 represents threshold 1, then otherwise .

4. A simplified passive intermodulation detection and elimination method according to claim 3, characterized in that: In the A2 process, the power of the received signal is calculated as follows: Let the power of the received signal be RXP, then: if Where thr2 represents threshold 2, then otherwise 。 5. A simplified passive intermodulation detection and elimination method according to claim 4, characterized in that: The determination method in the A3 process is as follows: Let the carrier frequencies of the transmission signals be , , …, from low to high, where T represents the number of transmitted carriers, and the bandwidth of the t-th (0 < t < T + 1) carrier is BW; the transmission frequency band of the transmission signal is from to , and the received frequency band of the received signal is from to ; , … , where T represents the number of transmitted carriers, and the bandwidth of the t-th (0 < t < T + 1) carrier is BW; the transmission frequency band of the transmission signal is from to , and the received frequency band of the received signal is from to ; if or So otherwise if , , If both are 1, it means that no passive intermodulation signal is detected and the process goes to step S2; otherwise, the process ends directly. entp represents the determination result of the transmit power, enrp represents the detection result of the receive power, and enft represents the final determination result of the transmit carrier.

6. A simplified passive intermodulation detection and elimination method according to claim 5, characterized in that: The process of constructing the passive intermodulation signal component in step S2 is as follows: Let the component of the input signal be , then we have: in Indicates the amplitude value of the signal.

7. A simplified passive intermodulation detection and elimination method according to claim 6, characterized in that: In step S3, the process of the passive intermodulation signal corresponding to the received signal is as follows: Where exp represents the exponential operation of the natural logarithm, Represents pi 3.1415926… an infinite non-repeating decimal.

8. The simplified passive intermodulation detection and elimination method according to claim 7, characterized in that: In step S4, the delay value calculation process between the sending signal and the receiving signal is as follows: Where conv represents convolution calculation, and arg represents the independent variable; Then Align with the received signal to get the delay result. The signal after the passive intermodulation signal is frequency-shifted, ； In step S5, the gain value calculation process between the transmitted signal and the received signal is as follows: , gain is the gain between the received signal and the transmitted signal.

9. The simplified passive intermodulation detection and elimination method according to claim 8, characterized in that: In step S6, the numerical calculation process of the received signal after the passive intermodulation signal is eliminated is as follows: Let the result after RX eliminates PIM be , that is, the result after completing the elimination of the passive intermodulation signal is as follows: 。 10. A simplified passive intermodulation detection and cancellation system, characterized in that: It includes the following modules: passive intermodulation signal detection module, signal component construction module, signal component frequency shifting module, delay numerical calculation module, gain numerical calculation module, and passive intermodulation elimination module; Passive intermodulation signal detection module: first calculate the power of the transmitted signal, then calculate the power of the received signal, Finally, it is detected whether the carrier frequency band of the transmitted signal will cause the passive intermodulation signal component to fall into the received signal, thereby completing the detection of the passive intermodulation signal; Signal component construction module: constructs the components of the received passive intermodulation signal; Signal component frequency shifting module: transfers the passive intermodulation signal component of the transmitted signal to the frequency point corresponding to the received signal; Delay value calculation module: calculates the delay value between the sending signal and the receiving signal; Gain value calculation module: calculates the gain value between the transmitted signal and the received signal; Passive intermodulation elimination module: calculates the value of the received signal after the passive intermodulation signal is eliminated, thereby completing the elimination of the passive intermodulation signal.

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