Channel quality assessment method for narrowband system and narrowband receiver

Abstract

The present application discloses a channel quality assessment method for a narrowband system and a narrowband receiver to select a frequency point with better channel quality. The operating frequency band of the narrowband system is divided into n frequency points, respectively referred to as the 1st, 2nd, ..., nth frequency points of the broadband frequency band. The method includes: when the narrowband receiver hops between the n frequency points, after the narrowband receiver hops to the i-th frequency point, calculating the power of the useful signal at the i-th frequency point and the power of the interference signal at the 1st, 2nd, ..., nth frequency points received by the narrowband receiver, where i = 1, 2, ..., n; after the narrowband receiver hops to the 1st, 2nd, ..., nth frequency point, performing a smoothing operation on the total power of the interference signal at the i-th frequency point; calculating the ratio of the power of the useful signal at the i-th frequency point to the smoothed power of the interference signal at the i-th frequency point to obtain a signal-to-interference-plus-noise ratio (SIN / INR) at the i-th frequency point, and evaluating the channel quality of the i-th frequency point based on the SIN / INR.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communications, and more particularly to a channel quality assessment method for a narrowband system and a narrowband receiver. Background Art

[0002] The 2.4 GHz band is a globally used ISM (Industrial, Scientific, and Medical) frequency band. It's a free frequency band. Wi-Fi (Wireless Fidelity), microwave ovens, Bluetooth, and other devices all operate in the 2.4 GHz band, making it very crowded. When narrowband and broadband systems (narrowband systems, such as Bluetooth, and broadband systems, such as Wi-Fi, are used interchangeably; narrowband is the term relative to broadband. Starting from World Telecommunication Day 2010, May 17, 2010, all frequencies less than 4 Mbps are considered narrowband, and only 4 Mbps or higher are considered broadband) coexist, some frequencies in the 2.4 GHz band are occupied by broadband systems, causing narrowband systems to consistently fail on these frequencies. To ensure communication quality, narrowband systems must avoid frequencies occupied by broadband systems and select frequencies with better channel quality. Accurate channel quality assessment is essential to selecting frequencies with better channel quality. Summary of the Invention

[0003] In view of this, the present invention provides a channel quality assessment method for a narrowband system and a narrowband receiver, so as to select a frequency point with better channel quality.

[0004] A channel quality assessment method for a narrowband system, wherein the operating frequency band of the narrowband system is divided into n frequency points, which are respectively referred to as the first, second, ..., nth frequency points of the broadband frequency band, where n ≥ 2, the method comprising:

[0005] During the process of the narrowband receiver frequency hopping between the n frequency points, after the narrowband receiver frequency hops to the i-th frequency point, calculating the power of the useful signal at the i-th frequency point and the power of the interference signals at the 1st, 2nd, ..., nth frequency points received by the narrowband receiver, where i = 1, 2, ..., n;

[0006] After the narrowband receiver frequency hops to the 1st, 2nd, ..., nth frequency points, all the above calculations to be performed are completed, a smoothing operation is performed on the total power of the interference signal at the i-th frequency point to obtain the smoothed power of the interference signal at the i-th frequency point;

[0007] The signal-to-interference-plus-noise ratio (SINR) of the i-th frequency point is calculated by calculating the ratio of the power of the useful signal at the i-th frequency point to the smoothed power of the interference signal at the i-th frequency point. This ratio is used to evaluate the channel quality of the i-th frequency point.

[0008] Optionally, after the narrowband receiver frequency hops to the i-th frequency point, the i-th frequency point is the operating frequency point, and the remaining n-1 frequency points are adjacent channel frequency points; correspondingly, after the narrowband receiver frequency hops to the i-th frequency point, calculating the power of the useful signal at the i-th frequency point and the power of the interference signals at the 1st, 2nd, ..., nth frequency points received by the narrowband receiver includes:

[0009] After the narrowband receiver hops to the i-th frequency point, the first analog-to-digital converter is used to sample the signal entering the narrowband receiver, and the sampled signal is converted into a time / frequency domain to obtain received signals at multiple frequency points including the n frequency points; and the power of the received signals at the multiple frequency points is calculated;

[0010] Calculating the noise floor of the narrowband receiver according to the power of the received signals at the multiple frequency points;

[0011] Sampling the useful signal at the operating frequency point using a second analog-to-digital converter, and calculating the power of the useful signal at the operating frequency point based on the sampling;

[0012] Calculate the power of the interference signal at the operating frequency and the power of the interference signal at each adjacent channel frequency;

[0013] The power of the interference signal at the working frequency is equal to the difference between the power of the received signal at the working frequency and a preset power, and the preset power is equal to the sum of the power of the useful signal at the working frequency and the background noise;

[0014] The power of the interference signal at the adjacent channel frequency point is equal to the difference between the power of the received signal at the adjacent channel frequency point and the background noise.

[0015] Optionally, when an upsampling multiple k of the first analog-to-digital converter is greater than or equal to n, sampling the signal input to the narrowband receiver using the first analog-to-digital converter and performing time / frequency domain conversion on the sampled signal to obtain received signals at multiple frequency points including the n frequency points includes: sampling the signal input to the narrowband receiver using the first analog-to-digital converter once, performing time / frequency domain conversion on the sampled signal to obtain received signals at k frequency points including the n frequency points;

[0016] Correspondingly, the calculation of the noise floor of the narrowband receiver based on the power of the received signals of the multiple frequency points includes: averaging the m numbers of the smallest values ​​of the power of the received signals of the k frequency points, and taking the average value as the noise floor of the narrowband receiver, <m<k。

[0017] Optionally, performing time / frequency domain conversion on the sampled signal includes: performing time / frequency domain conversion on the sampled signal using a fast Fourier transform (FFT) method.

[0018] Optionally, m=n / 2.

[0019] Optionally, k is the minimum upsampling multiple within the range of greater than or equal to n.

[0020] Optionally, sampling the useful signal at the operating frequency point using the second analog-to-digital converter and calculating the power of the useful signal at the operating frequency point based on the sampling includes:

[0021] A second analog-to-digital converter is used to sample the useful signal of the operating frequency, and a synchronization module is used to perform correlation operation on the local synchronization reference signal and the received signal of the operating frequency to obtain x related signals, where x is the code length of the synchronization reference signal and x>0; when the maximum value among the powers of the x related signals is greater than the synchronization threshold value, the maximum value is used as the power of the useful signal of the operating frequency.

[0022] Optionally, after the narrowband receiver frequency hops to the i-th frequency point, the method further includes: counting a block error rate at the i-th frequency point;

[0023] The aforementioned evaluating the channel quality of the i-th frequency point based on this is replaced by: comprehensively evaluating the channel quality of the i-th frequency point based on the signal to interference plus noise ratio and the block error rate of the i-th frequency point.

[0024] A narrowband receiver comprises: a processor and a memory; the processor is used to run a program stored in the memory, and when the program is run, the program executes any one of the narrowband system channel quality assessment methods disclosed above.

[0025] Optionally, the narrowband receiver is a Bluetooth receiver.

[0026] As can be seen from the above technical solution, the present invention calculates the signal-to-interference-and-noise ratios of multiple frequency points on the narrowband receiver side, evaluates the channel quality of the frequency points based on the signal-to-interference-and-noise ratios, and thus selects the frequency point with better channel quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A flow chart of a channel quality assessment method for a narrowband system disclosed in an embodiment of the present invention;

[0029] Figure 2 A flowchart of a method disclosed in an embodiment of the present invention for calculating the power of interference signals at the 1st, 2nd, ..., nth frequency points and the power of a useful signal at the i-th frequency point received by the narrowband receiver after the narrowband receiver frequency hops to the i-th frequency point;

[0030] Figure 3 A flow chart of a channel quality assessment method for a narrowband system disclosed in an embodiment of the present invention;

[0031] Figure 4 The figure is a schematic diagram of the structure of a narrowband receiver disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] For the purpose of reference and clarity, the technical terms, abbreviations or acronyms used below are summarized as follows:

[0033] ADC: Analog to Digital Converter, analog to digital converter;

[0034] RSSI: ReceivedSignalStrengthIndication, received signal strength indication;

[0035] LNA: Low Noise Amplifier, low noise amplifier;

[0036] TIA: Trans-Impedance Amplifier, transimpedance amplifier;

[0037] FFT: FastFourierTransform, fast Fourier transform;

[0038] SINR: Signal to Interference plus Noise Ratio, signal to interference plus noise ratio, referred to as signal to interference and noise ratio; SINR refers to the ratio of the strength of the received useful signal to the strength of the received interference signal (noise and interference), which can be simply understood as "signal to noise ratio";

[0039] CRC, or Cyclic Redundancy Check, is a fast algorithm that generates a short, fixed-number checksum based on data such as network packets or computer files. It is primarily used to detect or check errors that may occur after data transmission or storage. CRC uses the principles of division and remainder to implement error detection, and has the advantages of clear principles and simple implementation.

[0040] BLER: Block Error Rate, block error rate; BLER refers to the ratio of erroneous blocks to the total number of blocks received by the digital circuit, that is, the block error rate.

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not 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 efforts are within the scope of protection of the present invention.

[0042] See also Figure 1 The embodiment of the present invention discloses a channel quality assessment method for a narrowband system. The operating frequency band of the narrowband system is divided into n frequency points, which are respectively referred to as the first, second, ..., nth frequency points of the broadband frequency band, where n≥2. The method includes the following steps S01 to S04:

[0043] Step S01: During the frequency hopping process of the narrowband receiver among the n frequency points, after the narrowband receiver hops to the i-th frequency point, the power of the interference signals at the 1st, 2nd, ..., nth frequency points received by the narrowband receiver and the power of the useful signal at the i-th frequency point are calculated, where i = 1, 2, ..., n; then the process proceeds to step S02.

[0044] Specifically, the narrowband system uses frequency hopping technology to achieve spread spectrum communication. Frequency hopping technology is a communication method in which the carrier frequency of the wireless transmission signal between the transmitting and receiving devices is discretely changed according to a predetermined algorithm or rule. It can be seen that during the communication process, the transmitting and receiving devices will synchronously jump between the n frequency points. Taking Bluetooth 5.0 Classic Bluetooth (i.e., Bluetooth Core Specification Version 5.0) as an example of a narrowband system: the operating frequency band used by Bluetooth 5.0 Classic Bluetooth for Bluetooth data transmission is 2402MHz to 2480MHz within the 2.4G frequency band. Bluetooth 5.0 Classic Bluetooth has one frequency point for every 1MHz bandwidth, corresponding to a total of 79 frequency points. During the communication process, the Bluetooth 5.0 Classic Bluetooth transmitting and receiving devices will synchronously jump between the 79 frequency points of 2402MHz to 2480MHz.

[0045] When the receiver in a narrowband system, i.e., the narrowband receiver, operates at the i-th frequency point, the narrowband receiver will receive the useful signal (a narrowband signal) from the i-th frequency point. At the same time, interference signals will be generated at the 1st, 2nd, ..., nth frequency points of the broadband frequency band. The power of the useful signal from the i-th frequency point and the power of the interference signals from the 1st, 2nd, ..., nth frequency points of the broadband frequency band are related to the channel quality of the i-th frequency point, so it is necessary to accurately calculate the power of these signals.

[0046] Among them, see Figure 2 The specific implementation process of step S01 can be further divided into the following steps S011 to S014:

[0047] Step S011: After the narrowband receiver hops to the i-th frequency point, the first ADC is used to sample the signal entering the narrowband receiver, and the sampled signal is converted into the time / frequency domain to obtain received signals at multiple frequency points including the n frequency points; the power of the received signals at the multiple frequency points is calculated; and then the process proceeds to step S012.

[0048] Specifically, step S011 is a wideband RSSI calculation process. After a full-bandwidth signal transmitted from a narrowband transmitter to a narrowband receiver is processed by an LNA, a TIA, a filter circuit, and the like, the narrowband receiver samples the processed signal using a first ADC. The sampled signal is then converted from the time domain to the frequency domain to obtain received signals at multiple frequency points. The multiple frequency points can fully cover the n frequency points. In the frequency domain, the power of a frequency point signal represents the strength of the frequency point signal.

[0049] The method of converting the time domain to the frequency domain is, for example, FFT, but is not limited thereto.

[0050] The upsampling factor k of the first ADC (if the upsampling factor of the first ADC is k, the sampling rate of the first ADC is k*1 MHz) is reasonably selected according to the number of frequency points n of the narrowband receiver. The upsampling factor k is preferably greater than or equal to the lowest sampling rate within the range of n. This is because: when the narrowband receiver operates at the i-th frequency point, the i-th frequency point is the operating frequency point, and the remaining n-1 frequency points are adjacent channel frequencies. Subsequent calculations require the received signal of the operating frequency point of the narrowband receiver and the received signals of the n-1 adjacent channel frequencies; the first ADC performs sampling with the operating frequency point of the narrowband receiver as the center, and the first ADC performs sampling once (i.e., the number of sampling times is 1). After the time / frequency domain conversion, k frequency points of received signals will be obtained. When k ≥ n, these k frequency points are sufficient to fully cover the n frequency points of the narrowband receiver at one time. That is to say, from the sampling number of the first ADC, when k ≥ n, the first ADC only undergoes one sampling to obtain the k frequency points of received signals, which are sufficient to cover the n frequency points of received signals of the narrowband receiver. If an ADC with a larger upsampling multiple k is used, although the sampling of the received signals of the n frequency points can be completed with only one sampling, it is more cost-effective. If an ADC with an upsampling multiple k less than n is used, multiple frequency hopping and multiple sampling are required to sample all the received signals of the n frequency points, which is less efficient.

[0051] Taking the narrowband receiver as an example of the classic Bluetooth receiver in Bluetooth 5.0, its operating frequency band is 2402MHz to 2480MHz, with a total of 79 frequency points corresponding to one frequency point per 1MHz bandwidth. Among the ADCs with sampling rates of 64MHz, 128MHz, and 256MHz, the ADC with a sampling rate of 128MHz is preferably selected as the first ADC. The ADC with a sampling rate of 128MHz samples centered on the operating frequency points of the narrowband receiver. When the narrowband receiver operates at the 2440MHz frequency point, the received signals of 128 frequency points obtained through ADC sampling and time / frequency domain conversion are the received signals of the frequency points from 2377MHz to 2504MHz. The received signals of the frequency points from 2402MHz to 2480MHz are extracted for subsequent calculations; when the narrowband receiver operates at the 2441MHz frequency point, the received signals of 128 frequency points obtained through ADC sampling and time / frequency domain conversion are 2378MHz to 2505MHz;...; and so on. When the narrowband receiver operates at the 2480MHz frequency point, the received signals of 128 frequency points obtained through ADC sampling and time / frequency domain conversion are 2417MHz to 2544MHz (the received signals of the frequency points outside the range of 2402Mhz to 2480MHz do not need to be recorded).

[0052] Step S012: Calculate the noise floor of the narrowband receiver according to the power of the received signals of the multiple frequency points; then proceed to step S013.

[0053] Specifically, when the upsampling multiple k of the first ADC is ≥ n, the powers of the received signals of the k frequency points obtained are P1, P2,..., P k , then calculating the noise floor of the narrowband receiver according to the power of the received signals of the multiple frequency points includes: averaging the m smallest numbers among the values of P1, P2,..., P k , and taking the average value as the noise floor of the narrowband receiver, where 0 < m < k. The embodiment of the present invention recommends setting m = k / 2, but is not limited thereto.

[0054] If the upsampling multiple k of the first ADC is < n, then take the average of the m smallest numbers among the powers of the received signals of the k frequency points obtained after any one sampling, and take the average value as the noise floor of the narrowband receiver.

[0055] Step S013: Sample the useful signal of the operating frequency point with the second ADC, and calculate the power of the useful signal of the operating frequency point; then proceed to step S014.

[0056] Specifically, a second ADC is used to sample the useful signal of the working frequency, and a synchronization module is used to perform a correlation operation on the local synchronization reference signal and the received signal of the working frequency to obtain x related signals, where x is the code length of the synchronization reference signal and x>0; when the maximum value of the power of the x related signals is greater than the synchronization threshold value (that is, when synchronization is met), the maximum value is used as the power of the useful signal of the working frequency, so that the power of the useful signal of the working frequency obtained in this way is relatively accurate.

[0057] Step S014: Calculate the power of the interference signal at the working frequency and the power of the interference signal at each adjacent frequency. The calculation formula is as follows:

[0058] The power of the interference signal at the working frequency = the power of the received signal at the working frequency - the power of the useful signal at the working frequency - the noise floor;

[0059] The power of the interference signal at the adjacent channel frequency point=the power of the received signal at the adjacent channel frequency point-the noise floor.

[0060] Step S02: After all calculations to be performed after the narrowband receiver hops to the 1st, 2nd, ..., nth frequency points are completed, a smoothing operation is performed on the total power of the interference signal at the i-th frequency point to obtain the smoothed power of the interference signal at the i-th frequency point; then step S03 is entered.

[0061] Specifically, smoothing is exponential smoothing. Its basic concept is that the predicted value is a weighted sum of previous observations, with different data weights assigned differently: new data is given a larger weight, while older data is given a smaller weight. The power of the interference signal at the i-th frequency obtained through smoothing is more accurate.

[0062] Step S03: Calculate the ratio of the power of the useful signal at the i-th frequency point to the smoothed power of the interference signal at the i-th frequency point to obtain the SINR at the i-th frequency point; then proceed to step S04.

[0063] Step S04: Evaluate the channel quality of the i-th frequency point according to the SINR of the i-th frequency point.

[0064] As can be seen from the above description, the embodiment of the present invention calculates the signal to interference plus noise ratios (SINRs) of multiple frequency points at the narrowband receiver side, evaluates the channel quality of the frequency points based on the SINRs, and thus selects a frequency point with better channel quality.

[0065] Optionally, based on any of the above disclosed embodiments, the embodiment of the present invention may also introduce BLER, and then comprehensively evaluate the channel quality by combining SINR and BLER. The corresponding narrowband system channel quality evaluation method is as follows: Figure 3As shown, the operating frequency band of the narrowband system is divided into n frequency points, which are respectively referred to as the 1st, 2nd, ..., nth frequency points of the broadband frequency band, where n≥2. The method includes the following steps S21 to S24:

[0066] Step S21: During the process of the narrowband receiver hopping between the n frequency points, after the narrowband receiver hops to the i-th frequency point, the power of the interference signals at the 1st, 2nd, ..., nth frequency points and the power of the useful signal at the i-th frequency point received by the narrowband receiver are calculated, and the BLER at the i-th frequency point is counted, where i = 1, 2, ..., n; then the process proceeds to step S22.

[0067] Step S22: After all calculations to be performed after the narrowband receiver hops to the 1st, 2nd, ..., nth frequency points are completed, a smoothing operation is performed on the total power of the interference signal at the i-th frequency point to obtain the smoothed power of the interference signal at the i-th frequency point; then step S23 is entered.

[0068] Step S23: Calculate the ratio of the power of the useful signal at the i-th frequency point to the smoothed power of the interference signal at the i-th frequency point to obtain the SINR at the i-th frequency point; then proceed to step S24.

[0069] Step S24: The SINR and BLER of the i-th frequency point are integrated to evaluate the channel quality of the i-th frequency point.

[0070] Specifically, after the narrowband receiver hops to the i-th frequency point, the CRC of the data packet received by the narrowband receiver is decoded to obtain a CRC value. CRC = 0 indicates correct reception, and CRC = 1 indicates erroneous reception. A block error occurs when the CRC value of the erroneously received packet is 1. The interference situation of the corresponding frequency point is indirectly obtained by counting the BLER. The larger the BLER, the greater the degree of interference. Using only BLER or SINR to evaluate channel quality is prone to misjudgment. Therefore, an embodiment of the present invention combines the two to determine the channel quality of the operating frequency point. If the SINR of the operating frequency point is greater than a first preset value and the BLER of the operating frequency point is less than a second preset value, the frequency point is determined to be available.

[0071] In addition, the embodiment of the present invention also discloses a narrowband receiver, such as Figure 4 As shown, it includes: a processor and a memory;

[0072] The processor is configured to run a program stored in the memory, and when the program is run, any one of the narrowband system channel quality assessment methods disclosed above is executed.

[0073] Optionally, the narrowband receiver is a Bluetooth receiver, but is not limited to this.

[0074] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Reference will be made to the description of the methods disclosed in the embodiments for similar or identical parts. The narrowband receiver disclosed in the embodiments is described briefly because it corresponds to the methods disclosed in the embodiments. For relevant details, refer to the description of the methods.

[0075] The terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish between similar objects and are not necessarily used to describe a specific order or precedence. Furthermore, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, product, or apparatus comprising a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, product, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a" does not preclude the presence of additional identical elements in the process, method, product, or apparatus comprising the element.

[0076] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0077] As for the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple. For relevant parts, please refer to the partial description of the method embodiment. The device embodiment described above is only illustrative, in which the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without expending creative work.

[0078] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present invention. Therefore, the embodiments of the present invention are not limited to the embodiments shown herein, but are intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A channel quality assessment method for a narrowband system, wherein the operating frequency band of the narrowband system is divided into n frequency points, respectively referred to as the first, second, ..., nth frequency points of the broadband frequency band, where n ≥ 2, characterized in that: The method comprises: During the process of the narrowband receiver frequency hopping between the n frequency points, after the narrowband receiver frequency hops to the i-th frequency point, calculating the power of the useful signal at the i-th frequency point and the power of the interference signals at the 1st, 2nd, ..., nth frequency points received by the narrowband receiver, where i = 1, 2, ..., n; After the narrowband receiver frequency hops to the 1st, 2nd, ..., nth frequency points, all the above calculations to be performed are completed, a smoothing operation is performed on the total power of the interference signal at the i-th frequency point to obtain the smoothed power of the interference signal at the i-th frequency point; The signal-to-interference-plus-noise ratio (SINR) of the i-th frequency point is calculated by calculating the ratio of the power of the useful signal at the i-th frequency point to the smoothed power of the interference signal at the i-th frequency point. This ratio is used to evaluate the channel quality of the i-th frequency point.

2. The channel quality assessment method for a narrowband system according to claim 1, wherein: When the narrowband receiver frequency hops to the i-th frequency point, the i-th frequency point is the operating frequency point, and the remaining n-1 frequency points are adjacent channel frequency points; correspondingly, when the narrowband receiver frequency hops to the i-th frequency point, calculating the power of the useful signal at the i-th frequency point and the power of the interference signals at the 1st, 2nd, ..., nth frequency points received by the narrowband receiver includes: After the narrowband receiver hops to the i-th frequency point, the first analog-to-digital converter is used to sample the signal entering the narrowband receiver, and the sampled signal is converted into a time / frequency domain to obtain received signals at multiple frequency points including the n frequency points; and the power of the received signals at the multiple frequency points is calculated; Calculating the noise floor of the narrowband receiver according to the power of the received signals at the multiple frequency points; Sampling the useful signal at the operating frequency point using a second analog-to-digital converter, and calculating the power of the useful signal at the operating frequency point based on the sampling; Calculate the power of the interference signal at the operating frequency and the power of the interference signal at each adjacent channel frequency; The power of the interference signal at the working frequency is equal to the difference between the power of the received signal at the working frequency and a preset power, and the preset power is equal to the sum of the power of the useful signal at the working frequency and the background noise; The power of the interference signal at the adjacent channel frequency point is equal to the difference between the power of the received signal at the adjacent channel frequency point and the background noise.

3. The channel quality assessment method for a narrowband system according to claim 2, wherein: When the upsampling multiple k of the first analog-to-digital converter is greater than or equal to n, sampling the signal input to the narrowband receiver using the first analog-to-digital converter and performing time / frequency domain conversion on the sampled signal to obtain received signals at multiple frequency points including the n frequency points includes: sampling the signal input to the narrowband receiver using the first analog-to-digital converter once, performing time / frequency domain conversion on the sampled signal to obtain received signals at k frequency points including the n frequency points; Correspondingly, the calculation of the noise floor of the narrowband receiver based on the power of the received signals of the multiple frequency points includes: averaging the m numbers of the smallest values ​​of the power of the received signals of the k frequency points, and taking the average value as the noise floor of the narrowband receiver, <m<k。 4. The narrowband system channel quality assessment method according to claim 2 or 3, characterized in that: The time / frequency domain conversion of the sampled signal includes: using a fast Fourier transform (FFT) method to perform time / frequency domain conversion on the sampled signal.

5. The channel quality assessment method for a narrowband system according to claim 3, wherein: m=n / 2.

6. The channel quality assessment method for a narrowband system according to claim 3, wherein: k is the minimum upsampling multiple within the range of greater than or equal to n.

7. The channel quality assessment method for a narrowband system according to claim 2 or 3, characterized in that: The sampling of the useful signal at the operating frequency point by the second analog-to-digital converter and calculation of the power of the useful signal at the operating frequency point based on the sampling comprises: A second analog-to-digital converter is used to sample the useful signal of the operating frequency, and a synchronization module is used to perform correlation operation on the local synchronization reference signal and the received signal of the operating frequency to obtain x related signals, where x is the code length of the synchronization reference signal and x>0; when the maximum value among the powers of the x related signals is greater than the synchronization threshold value, the maximum value is used as the power of the useful signal of the operating frequency.

8. The channel quality assessment method for a narrowband system according to claim 1, wherein: When the narrowband receiver hops to the i-th frequency point, the method further includes: counting the block error rate at the i-th frequency point; The aforementioned evaluating the channel quality of the i-th frequency point based on this is replaced by: comprehensively evaluating the channel quality of the i-th frequency point based on the signal to interference plus noise ratio and the block error rate of the i-th frequency point.

9. A narrowband receiver, characterized in that: include: processor and memory; The processor is configured to run the program stored in the memory, and the program, when running, executes the channel quality assessment method for a narrowband system according to any one of claims 1 to 8.

10. The narrowband receiver according to claim 9, characterized in that The narrowband receiver is a Bluetooth receiver.

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