A method for measuring background noise of a communication channel

Abstract

The application discloses a method for measuring background noise of a communication channel, which comprises the following steps: switching a communication device from a first frequency point to a second frequency point in a short interframe interval after the communication device sends data, the first frequency point being a frequency point used by the communication device in an original transceiving process, and the second frequency point being a frequency point for which background noise is to be tested; opening a receiving channel of the communication device to sample signals; switching the frequency point of the communication device back to the first frequency point after the sampling is completed, and continuing the original transceiving process; and calculating the energy of the sampled signals as background noise. The application utilizes the characteristics of wireless communication to switch the frequency point of the communication device to the frequency point for which background noise is to be tested at a suitable time to collect background noise signals, the communication channel is in an idle state during the collection, and pure background noise can be easily detected, so that the reliability is high. Moreover, the method of the application completes the switching of the frequency and the collection of the signals in a short time, does not affect current communication, and is practical.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, and specifically relates to a method for measuring background noise in a communication channel. Background Technology

[0002] Signal-to-noise ratio (SNR) refers to the ratio of signal to noise in an electronic device or system. The presence of noise in a communication channel affects communication reliability. Various types of noise exist in communication channels, with background noise being one of them. Background noise is an irregular, extraneous signal not present in the original signal and does not change with the original signal. According to the definition of SNR, when there is no other noise in the communication channel except for background noise, the magnitude of the background noise can be calculated by inversely from the magnitude of the received signal and the SNR, thus evaluating the communication channel. While this method of calculating noise is intuitive, it requires a received signal and a known SNR. Calculating the SNR requires estimation in the frequency domain using Fourier transform, which is computationally intensive. Therefore, this method of calculating background noise in a communication channel based on the definition of SNR is not very practical. Summary of the Invention

[0003] The purpose of this invention is to provide a simple and effective method for measuring background noise in communication channels.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for measuring background noise in a communication channel includes the following steps:

[0006] S1. Within a short frame interval after the communication device transmits data, switch the communication device from the first frequency point to the second frequency point. The first frequency point is the frequency point used by the communication device in the original transmission and reception process, and the second frequency point is the frequency point where the background noise is to be tested.

[0007] S2. Open the receiving channel of the communication device to sample the signal;

[0008] S3. After sampling is complete, switch the frequency of the communication device back to the first frequency and continue the original transmission and reception process.

[0009] S4. Calculate the energy of the sampled signal as background noise.

[0010] Optionally, in the method for measuring background noise of the communication channel as described above, if there are multiple samplings during the short inter-frame interval, the energy of each sampled data is calculated, and the minimum value among all the calculated energy of the sampled data is taken as the background noise.

[0011] In the communication channel background noise measurement method described above, optionally, in step S4, before calculating the signal energy, the validity of the sampling result is determined:

[0012] a. If the first frequency point and the second frequency point are different, the energy of the signal can be directly calculated as the background noise based on the sampled data;

[0013] b. When the first frequency point and the second frequency point are the same, if the communication device sends an acknowledgment frame, or if the communication device sends a data frame and receives an acknowledgment frame within a set time, the background noise can be directly calculated based on the sampled data; otherwise, the sampled data is considered to be interfered with and unreliable, and is discarded.

[0014] Optionally, in step b, when the first frequency point and the second frequency point are the same, and the communication device sends an acknowledgment frame, or the communication device sends a data frame and receives an acknowledgment frame within a set time, the signal is sampled only once within the short frame interval.

[0015] As can be seen from the above technical solutions, the present invention utilizes the characteristics of wireless communication to switch the frequency of the communication device to the frequency of the background noise to be tested at an appropriate time to collect the background noise signal. During the collection period, the communication channel is in an idle state and will not be interfered with by other communication devices. It is relatively easy to detect simple background noise, with high reliability. Moreover, the method of the present invention completes the frequency switching and signal collection in a short time without affecting the current communication, and has good practicality. Attached Figure Description

[0016] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart illustrating the workflow of the CSMA / CA mechanism;

[0018] Figure 2 This is a flowchart of the method of the present invention.

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings. In the detailed description of the embodiments of the present invention, for ease of explanation, the drawings illustrating the device structure will be partially enlarged without adhering to the general scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of the present invention. It should be noted that the drawings are in a simplified form and use non-precise scales, solely for the purpose of conveniently and clearly illustrating the embodiments of the present invention. Additionally, in the description of this application, terms such as "first" and "second" are used only to distinguish descriptions and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Terms such as "positive," "negative," "bottom," "upper," and "lower" indicate orientation or positional relationships based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Wireless communication is a communication method that utilizes the property that electromagnetic waves can propagate in free space to exchange information. Because electromagnetic waves do not require a medium to propagate, wireless communication, compared to wired communication, does not require the installation of communication lines, making it simpler to implement and leading to its increasingly widespread application in recent years.

[0023] According to the 802.11 protocol, wireless communication devices often employ CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) when accessing the channel to reduce the probability of data transmission collisions between devices. For example... Figure 1 As shown, the communication flow of the CSMA / CA mechanism is as follows:

[0024] When communication device 1 needs to send a data frame, it first checks whether the communication channel is idle. If the length of the idle time of the communication channel reaches the length of the Distributed Inter-Frame Space (DIFS), then communication device 1 starts sending data.

[0025] When communication device 2 receives a data frame from communication device 1, it first waits for a frame interval time, and then sends an acknowledgment frame (ACK) for the data frame received from communication device 1. The frame interval time that communication device 2 waits for is called the Short Inter-Frame Space (SIFS).

[0026] If communication device 1 does not receive an acknowledgment frame within a specified time after sending data, it will resend the data until an acknowledgment frame is received, or until the number of failed transmissions reaches a threshold, at which point it will abandon the transmission.

[0027] The length of the frame interval (SIFS) that communication device 2 waits for after receiving a data frame is less than the length of the distributed inter-frame interval (DIFS). As can be seen from the above process, when there is no collision on the communication channel, no communication device will send a signal again during the frame interval after communication device 1 sends data; at this time, the communication channel is in an idle state. Based on these characteristics of the communication channel, this invention uses the frame interval after a communication device sends data to measure the background noise of the communication channel. Since no communication device is sending a signal during this time, it is not affected by current communication, and the measured signal can be considered as the background noise of the communication channel.

[0028] Figure 2 The flowchart of the method of the present invention is as follows: Figure 2 As shown, the steps of the method for measuring background noise in a communication channel according to the present invention are as follows:

[0029] S1. Within the short inter-frame interval after the communication device transmits data, the communication device transmitting data is switched from the first frequency point f0 to the second frequency point f1. The first frequency point f0 is the frequency point used by the communication device transmitting data in the original transmission and reception process, and the second frequency point f1 is the frequency point where the background noise is to be tested. The communication device can have multiple available communication frequencies. Taking 802.11ah as an example, the available frequency bands of the communication device using the 802.11ah protocol are divided into 2MHz channels. The available frequencies include 864MHz and 866MHz. The communication device can communicate on the communication channels corresponding to these two frequencies. When you want to test a certain communication channel, you can switch the frequency point of the communication device to the corresponding frequency point.

[0030] S2. Open the receiving channel of the communication device to sample the signal;

[0031] S3. After sampling is complete, switch the frequency of the communication device back to the original frequency and continue the original transmission and reception process.

[0032] S4. Calculate the energy of the sampled signal as background noise.

[0033] For example, the communication device was originally transmitting and receiving data on frequency point f0. After the communication device transmits data, within the SIFS after transmitting the data, the frequency point of the communication device is switched to the frequency point where the background noise is to be tested, such as frequency point f1, to collect the background noise signal. After the collection is completed, the frequency point of the communication device is switched back to the original frequency point f0 and the original transmission and reception process continues.

[0034] In step S2, when sampling the signal within SIFS, multiple samplings may be performed by the ADC chip, resulting in multiple data segments. Once a segment of ADC data is collected, its energy can be calculated as background noise. Sampling once within SIFS yields one data segment. When multiple samplings result in more than one data segment, the energy of each segment can be calculated separately. The minimum energy among all calculated data segments is then taken as the background noise.

[0035] In step S4, the method for calculating the signal energy based on the ADC data is known. Below is a commonly used formula for calculating signal energy. In the formula, P represents the energy of the signal, (I0,Q0), (I1,Q1), ..., (I N Q N ) represent N data points obtained from a single sampling (a data segment consists of N data points), I i Q i Let C be the i-th data point during the i-th sampling, and K be the conversion gain of the sampling chip. gain This represents the gain of the RF front end. The above formula is only an example to illustrate how signal energy is calculated. There are other methods in the prior art for calculating signal energy. Signal energy calculation is a mature technology and is not an innovation of this invention, so it will not be elaborated here.

[0036] Optionally, in step S4, before calculating the signal energy, there is a step to determine whether the sampling result is valid. This step is as follows:

[0037] a. If the first frequency point f0 and the second frequency point f1 are different, the energy of the signal can be directly calculated as the background noise based on the sampled data; when f0 and f1 are different, it means that the signal being measured is different from the current transmit and receive frequency, and the measurement will not be affected by the original communication channel.

[0038] b. When the first frequency point f0 and the second frequency point f1 are the same, if the communication device sends an acknowledgment frame, or sends a data frame and receives an acknowledgment frame within the set time, it indicates that there are no other interference signals in the communication channel (interference signals may prevent the generation of acknowledgment frames), and the sampled data is the true background noise, which can be directly calculated from the sampled data; otherwise (corresponding to other cases where f0 and f1 are on the same frequency and no acknowledgment frame is sent, or no acknowledgment frame is received after sending a data frame), the sampled data is considered to be interfered with, the data is unreliable, and it is discarded. To improve efficiency, when the first frequency point f0 and the second frequency point f1 are the same, if the communication device sends an acknowledgment frame, or sends a data frame and receives an acknowledgment frame within the set time, only one signal sampling is required within SIFS, instead of sampling multiple times and taking the minimum value of the signal energy from multiple samplings as the background noise.

[0039] By determining the validity of the sampling structure, potential collisions in wireless communication can be avoided, ensuring the reliability of background noise measurements. Once the background noise is obtained, its value can be used to evaluate the quality of the communication channel. Higher background noise indicates poorer channel quality, while lower noise indicates better quality. Channel selection is then based on the evaluation results. Furthermore, the sampled data can be analyzed, such as statistically analyzing the signal's time-domain characteristics (maximum, minimum, and average values), calculating the signal's energy, and performing FFT analysis to identify other frequency components. These analysis results are then used to evaluate the communication channel quality.

[0040] The aforementioned embodiments are illustrated using the timing of the 802.11ah standard as an example. However, the method of the present invention is not limited to communication networks using the 802.11ah timing; it can also be applied to wireless communication networks such as 802.11bgn and Bluetooth. By switching frequencies within SIFS, the signal is collected as background noise. After the collection is complete, the original frequency is switched back without affecting the current communication. The measurement method is simple and reliable, and the background noise measurement results can be used as a reference for channel quality detection and for the selection of communication channels. Moreover, it is not limited to the current communication channel (frequency) and has high practical value.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for measuring background noise in a communication channel, characterized in that, Includes the following steps: S1. Within a short frame interval after the communication device transmits data, switch the communication device from the first frequency point to the second frequency point. The first frequency point is the frequency point used by the communication device in the original transmission and reception process, and the second frequency point is the frequency point where the background noise is to be tested. S2. Open the receiving channel of the communication device to sample the signal; S3. After sampling is complete, switch the frequency of the communication device back to the first frequency and continue the original transmission and reception process. S4. Calculate the energy of the sampled signal as background noise.

2. The method for measuring background noise of a communication channel as described in claim 1, characterized in that: When sampling the signal within the short frame interval, if there are multiple samples, the energy of each sampled data is calculated separately, and the minimum value among all the calculated energy of the sampled data is taken as the background noise.

3. The method for measuring background noise of a communication channel as described in claim 1, characterized in that: In step S4, before calculating the signal energy, the validity of the sampling result is determined: a. If the first frequency point and the second frequency point are different, the energy of the signal can be directly calculated as the background noise based on the sampled data; b. When the first frequency point and the second frequency point are the same, if the communication device sends an acknowledgment frame, or if the communication device sends a data frame and receives an acknowledgment frame within a set time, the background noise can be directly calculated based on the sampled data; otherwise, the sampled data is considered to be interfered with and unreliable, and is discarded.

4. The method for measuring background noise of a communication channel as described in claim 3, characterized in that: In step b, when the first frequency point and the second frequency point are the same, and the communication device sends an acknowledgment frame, or the communication device sends a data frame and receives an acknowledgment frame within a set time, the signal is sampled only once within the short frame interval.

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