Interference signal center frequency calculation method for 5G base station receiver intermodulation test

Abstract

The invention discloses an interference signal center frequency calculation method for a 5G base station receiver intermodulation test, and belongs to the technical field of test. The method provided by the invention has the characteristics of symbolization and formulation, has good universality, and can meet the requirements of center frequencies of CW interference signals, NR interference signals and NR narrowband interference signals in a 5G base station receiver intermodulation test scene specified in a 3GPP (3rd Generation Partnership Project) protocol; along with continuous evolution of a 3GPP protocol and continuous development of a communication technology, the method also has good expandability for new receiver intermodulation test scenes and requirements which may occur in the future; according to the method, the calculation process of the interference signal center frequency is expressed in a unified mode, the calculation process is simplified, the processes of manual corresponding table searching and manual calculation are avoided, the test efficiency is improved, and development and production efficiency of related products can be enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of testing technology, and in particular relates to a method for calculating the center frequency of an interference signal for intermodulation testing of a 5G base station receiver. Background Art

[0002] In 5G base station receiver intermodulation testing, third-order and higher-order mixing of two interfering radio frequency (RF) signals can generate interference signals in the frequency band of the desired channel. Intermodulation response suppression is a measure of the ability of a receiver to receive a desired signal at its specified channel frequency at the antenna port in the presence of two interfering signals with a specific frequency relationship to the desired signal. The purpose of receiver intermodulation testing is to verify the ability of a base station receiver to suppress its nonlinear intermodulation products, which are generated by two high-power interfering signals. The two interfering signals are a continuous wave (CW) signal and an NR signal, and the interfering signal frequency has a specific relationship with the desired signal frequency. Studying the calculation method of the interference signal center frequency is of great significance for correctly generating the interference signal required for the test, and it also has significant guiding significance for the development of test case functions for 5G NR base stations.

[0003] The existing solution only calculates the center frequency of the interference signal for the specific base station channel bandwidth scenario described in the 3GPP protocol, and does not provide a calculation method for general test scenarios. Although the center frequency of CW interference signals and NR interference signals can be calculated, it is limited to the interference signal bandwidth combination specified in the 3GPP protocol. With the development of technology and the evolution of protocols, if user-defined or non-standard interference signals or expected signal bandwidth combinations appear, the existing solution needs to formulate a calculation method for the new scenario before it can be put into use.

[0004] On the other hand, the existing solution combines the provisions of the 3GPP protocol. During the intermodulation test of the 5G base station receiver, it is necessary to first find the corresponding table in the protocol according to the expected signal bandwidth and the interference signal type, and then obtain the center frequency of the specific interference signal by manual calculation. If the expected signal bandwidth or the interference signal type changes, it is necessary to re-find the corresponding row in the table, and then manually calculate to obtain the new interference signal center frequency.

[0005] Disadvantages of existing technology

[0006] The 3GPP protocol specification for 5G base station receiver intermodulation characteristic testing will gradually evolve and add new test cases. At the same time, the efficiency of 5G base station receiver intermodulation testing will have a certain impact on the development and production progress of related products. Comprehensive analysis of existing solutions found that the current interference signal center frequency calculation solution for 5G base station receiver intermodulation testing has the following deficiencies:

[0007] 1. There is a lack of center frequency calculation methods for common test scenarios, and it is impossible to iterate and adapt to changing test scenarios in a timely manner.

[0008] 2. It relies on a lot of manual search and manual calculation processes, lacks a unified calculation method, and the testing efficiency is low.

[0009] The above shortcomings not only affect the effectiveness of coping with protocol evolution and technological development, but also limit the improvement of related product research and development and production efficiency. Summary of the invention

[0010] In view of the above-mentioned technical problems existing in the prior art, the present invention proposes a method for calculating the center frequency of an interference signal for intermodulation testing of a 5G base station receiver. The method has a reasonable design, overcomes the shortcomings of the prior art, and has good effects.

[0011] In order to achieve the above object, the present invention adopts the following technical solution:

[0012] A method for calculating the center frequency of an interference signal for 5G base station receiver intermodulation testing comprises the following steps:

[0013] Step 1: Calculate the center frequency of the CW interference signal;

[0014] Step 2: Calculate the center frequency of the NR interference signal;

[0015] Step 3: Calculate the center frequency of the NR narrowband interference signal.

[0016] Preferably, in step 1, the CW interference signal is a frequency point in the frequency domain, and there is a frequency offset Δf1 between the CW interference signal and the edge of the center frequency band of the desired signal. The center frequency of the CW interference signal is recorded as f c,0 Represents; then its expression is:

[0017] f c,0 =f0+W / 2+Δf1;

[0018] Wherein, f0 is the center frequency of the desired signal, W is the channel bandwidth of the desired signal, and Δf1 is the frequency offset of the center frequency of the CW interference signal relative to the edge of the desired signal frequency band.

[0019] Preferably, in step 2, the NR interference signal has a certain bandwidth, and there is a frequency offset Δf2 between its center frequency and the edge of the desired signal band. According to the characteristics of the 5G NR frequency grid, the center frequency position of a subcarrier has a frequency offset of half a subcarrier relative to its starting position. When calculating the center frequency of the NR interference signal, half a subcarrier spacing is added to the center frequency of the CW interference signal, that is, S / 2; the center frequency of the NR interference signal is recorded as f c,1 ; then its expression is:

[0020] f c,1 =f0+W / 2+Δf2+S / 2;

[0021] Wherein, S is the subcarrier spacing of the NR interference signal; Δf2 is the frequency offset between the center frequency of the NR interference signal and the edge of the desired signal band.

[0022] Preferably, in step 3, the NR narrowband interference signal occupies only one RB, which is within the NR interference signal bandwidth, and there is a frequency offset Δf3 between the center frequency of the NR interference signal and the edge of the desired signal band.

[0023] The center frequency of the NR narrowband interference signal is the center frequency of the RB it occupies, specifically:

[0024] On the basis of the corresponding NR interference signal center frequency calculation formula, add the frequency value represented by half of the number of RBs. At the same time, since the narrowband signal center frequency is at the center of the RB, subtract the frequency value represented by half of the RB.

[0025] The center frequency of the NR narrowband interference signal is denoted as f c,1 ; then its expression is:

[0026] f c,1 =f0+W / 2+Δf3+S / 2+(N / 2-1 / 2)*S*12;

[0027] Wherein, N is the number of RBs of the interference signal; Δf3 is the frequency offset between the center frequency of the NR interference signal and the edge of the desired signal band.

[0028] Beneficial technical effects brought by the present invention:

[0029] 1. The present invention proposes a method for calculating the center frequency of interference signals for 5G base station receiver intermodulation testing. The method is symbolic and formulaic, has good versatility, and can meet the requirements of the center frequencies of CW interference signals, NR interference signals, and NR narrowband interference signals in the 5G base station receiver intermodulation test scenarios specified in the 3GPP protocol. With the continuous evolution of the 3GPP protocol and the continuous development of communication technology, the method also has good scalability for new receiver intermodulation test scenarios and requirements that may appear in the future.

[0030] 2. The interference signal center frequency calculation method for 5G base station receiver intermodulation test proposed in the present invention unifies the calculation process of the interference signal center frequency, simplifies the calculation process, avoids manual search for corresponding tables and manual calculations, improves test efficiency, and helps to enhance the development and production efficiency of related products. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the frequency domain position of the desired signal and the CW interference signal;

[0032] Figure 2 Schematic diagram of the frequency domain position of the desired signal and the NR interference signal;

[0033] Figure 3 Schematic diagram of the frequency domain positions of the desired signal, NR interference signal, and NR narrowband interference signal. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0035] The basic idea of ​​the technical solution of the present invention is to summarize and refine the general interference signal center frequency calculation method based on the 3GPP protocol description, and use a symbolic form to give a universal interference signal center frequency calculation formula applicable to different types of interference signals.

[0036] Let the center frequency and channel bandwidth of the desired signal be f0 and W respectively, the center frequency of the interference signal be offset from the edge of the desired signal band by Δf, the subcarrier spacing of the NR interference signal be S, and the number of RBs of the interference signal be N. According to the 3GPP protocol, the frequency of the interference signal may be located above the frequency of the desired signal or below the frequency of the desired signal. The present invention uses a higher frequency interference signal as an example to explain the calculation method of the center frequency of interference signals of types such as CW, NR, and NR narrowband. The center frequency of the lower frequency interference signal is the mirror image of the center frequency of the higher frequency interference signal relative to the center frequency of the desired signal.

[0037] 1. Calculation of center frequency of CW interference signal

[0038] The CW interference signal is a frequency point in the frequency domain. According to the 3GPP protocol, there is a frequency offset between the CW interference signal and the edge of the center frequency band of the desired signal. This can be used to obtain the frequency domain positions of the desired signal and the CW interference signal. Figure 1 shown.

[0039] Figure 1 The frequency of the CW interference signal is f c,0 express.

[0040] from Figure 1 It can be seen that the center frequency of the CW interference signal is f c,0 =f0+W / 2+Δf.

[0041] 2. Calculation of the center frequency of the NR interference signal

[0042] The NR interference signal has a certain bandwidth, and its center frequency has a certain offset Δf from the edge of the desired signal band, such as Figure 2shown.

[0043] According to the characteristics of the 5G NR frequency grid, the center frequency position of a subcarrier has a frequency offset of half a subcarrier relative to its starting position. Therefore, when calculating the center frequency of the NR interference signal, it is necessary to add half a subcarrier spacing, that is, S / 2, on the basis of the center frequency of the CW interference signal.

[0044] The center frequency of the NR interference signal is denoted as f c,1 , then f c,1 =f0+W / 2+Δf+S / 2.

[0045] 3. NR narrowband interference signal center frequency calculation

[0046] The NR narrowband interference signal only occupies one RB, which is within the NR interference signal bandwidth, and the NR interference signal center frequency has a certain offset Δf from the edge of the desired signal band. The positions of the desired signal, NR interference signal, and NR narrowband interference signal in the frequency domain are shown in the figure. Figure 3 shown.

[0047] The center frequency of the NR narrowband interference signal is the center frequency of the RB it occupies and needs to be calculated separately. It can be calculated indirectly based on the center frequency of the NR interference signal and the number of RBs occupied by the NR interference signal.

[0048] Specifically, it is necessary to add the frequency value represented by half of the number of RBs to the corresponding NR interference signal center frequency calculation formula. At the same time, since the narrowband signal center frequency is at the center of the RB, the frequency value represented by half of the RB must be subtracted.

[0049] The center frequency of the NR narrowband interference signal is denoted as f c,1 .

[0050] Then f c,1 =f0+W / 2+Δf+S / 2+(N / 2-1 / 2)*S*12.

[0051] Key point and protection point 1CW interference signal center frequency calculation method

[0052] Based on the description of the CW interference signal required for receiver intermodulation testing in the 3GPP protocol, this patent summarizes and refines the frequency domain positions of the expected signal and the CW interference signal, and proposes a method for calculating the center frequency of the CW interference signal. This method is not only compatible with the requirements of the 3GPP protocol, but also, through symbolic and formulaic expressions, is suitable for new test scenarios proposed by future protocol evolution and technological development, and has good versatility and scalability.

[0053] Calculation method of center frequency of 2NR interference signal at key point and protection point

[0054] This patent is based on the description of receiver intermodulation test and NR interference signal in 3GPP protocol, and refines the relationship between the desired signal and the frequency domain position of NR interference signal. The relationship between the center frequency of NR interference signal and the center frequency of CW interference signal is obtained by analysis, and on this basis, a symbolic and formulated method for calculating the center frequency of NR interference signal is proposed. This method is not only suitable for the receiver intermodulation test scenarios specified in the existing 3GPP protocol, but also has good scalability for the test scenarios in the technical research process and user-defined.

[0055] Calculation method of center frequency of 3NR narrowband interference signal at key points and protection points

[0056] This patent combines the description of NR interference signal and NR narrowband signal in the receiver intermodulation test scenario of the 3GPP protocol, and summarizes the frequency domain position relationship between the desired signal, NR interference signal and NR narrowband interference signal. On this basis, the center frequency calculation method of the NR narrowband interference signal is obtained by analyzing the calculation formula of the center frequency of the NR interference signal. This method has the characteristics of symbolization and formulation. It not only complies with the provisions of the 3GPP protocol, but also can be used to calculate the center frequency of the NR narrowband interference signal when new test scenarios and test requirements emerge with the evolution of the protocol and the development of technology.

[0057] Key Points and Protection Points 4 Method for Calculating the Interference Signal Center Frequency for Receiver Intermodulation Testing

[0058] This patent analyzes the frequency domain position relationship between CW interference signals, NR interference signals, NR narrowband interference signals and the desired signal to obtain a formulaic and symbolic interference signal center frequency calculation method with good versatility and scalability. This method not only meets the interference signal generation requirements of the receiver intermodulation test in the 3GPP protocol, but can also be extended to new test scenarios where users define interference signal types during technical research.

[0059] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for calculating the center frequency of an interference signal for 5G base station receiver intermodulation testing, characterized in that: The steps include: Step 1: Calculate the center frequency of the CW interference signal; Step 2: Calculate the center frequency of the NR interference signal; Step 3: Calculate the center frequency of the NR narrowband interference signal.

2. The method for calculating the center frequency of interference signals for 5G base station receiver intermodulation testing according to claim 1, characterized in that: In step 1, the CW interference signal is a frequency point in the frequency domain. There is a frequency offset Δf1 between the CW interference signal and the edge of the center frequency band of the desired signal. The center frequency of the CW interference signal is recorded as f c,0 Represents; then its expression is: f c,0 =f0+W / 2+Δf1; Wherein, f0 is the center frequency of the desired signal, W is the channel bandwidth of the desired signal, and Δf1 is the frequency offset of the center frequency of the CW interference signal relative to the edge of the desired signal frequency band.

3. The method for calculating the center frequency of interference signals for 5G base station receiver intermodulation testing according to claim 1, characterized in that: In step 2, the NR interference signal has a certain bandwidth, and there is a frequency offset Δf2 between its center frequency and the edge of the desired signal band. According to the characteristics of the 5G NR frequency grid, the center frequency position of a subcarrier has a frequency offset of half a subcarrier relative to its starting position. When calculating the center frequency of the NR interference signal, half a subcarrier spacing is added to the center frequency of the CW interference signal, that is, S / 2; the center frequency of the NR interference signal is recorded as f c,1 ; then its expression is: f c,1 =f0+W / 2+Δf2+S / 2; Wherein, S is the subcarrier spacing of the NR interference signal; Δf2 is the frequency offset between the center frequency of the NR interference signal and the edge of the desired signal band.

4. The method for calculating the center frequency of interference signals for 5G base station receiver intermodulation testing according to claim 1, characterized in that: In step 3, the NR narrowband interference signal occupies only one RB, which is within the NR interference signal bandwidth, and there is a frequency offset Δf3 between the center frequency of the NR narrowband interference signal and the edge of the desired signal band. The center frequency of the NR narrowband interference signal is the center frequency of the RB it occupies, specifically: On the basis of the corresponding NR interference signal center frequency calculation formula, add the frequency value represented by half of the number of RBs. At the same time, since the NR narrowband signal center frequency is at the center of the RB, subtract the frequency value represented by half of the RB. The center frequency of the NR narrowband interference signal is denoted as f c,1 ; then its expression is: f c,1 =f0+W / 2+Δf3+S / 2+(N / 2-1 / 2)*S*12; Wherein, N is the number of RBs of the NR narrowband interference signal; Δf3 is the frequency offset between the center frequency of the NR narrowband interference signal and the edge of the desired signal band.

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