A medium range wireless transmission method

Abstract

The application discloses a kind of medium distance wireless transmission methods, comprising the following steps: S1: terminal equipment sends connection request frame by main control frequency band, contains equipment ID and signal strength RSSI value;S2: gateway receives request, and channel quality index is calculated based on RSSI value, and based on result dynamic distribution to auxiliary frequency band;S3: main control frequency band adopts FSK modulation transmission control instruction, and auxiliary frequency band adopts QPSK-OFDM modulation transmission data packet;S4: when data transmission, channel parameter is collected once every 10ms, if packet loss rate>5%, then auxiliary frequency band is switched to π / 4-DQPSK modulation transmission.The beneficial effects of the present application are: based on RSSI value calculation channel quality index, and based on result dynamic distribution to auxiliary frequency band or main control frequency band, cleverly adopt double-band collaborative transmission mechanism, through real-time monitoring channel quality dynamic switching modulation mode, improve the reliability of data packet transmission.

Description

Technical Field

[0001] This invention relates to the field of Internet of Things (IoT) technology, and in particular to a medium-range wireless transmission method. Background Technology

[0002] Existing single-band mid-range wireless transmission has the following main drawbacks: First, single-band transmission is limited by the available spectrum bandwidth, which cannot meet the large-scale data transmission needs of modern power systems. Traditional wireless communication technologies often exhibit problems such as insufficient bandwidth and high transmission latency when facing large-scale data transmission. This bandwidth limitation is particularly evident in scenarios that require the transmission of video or large amounts of sensor data. Second, in complex electromagnetic environments, single-band devices are susceptible to co-channel interference. For example, the 2.4GHz band has Bluetooth, WiFi, and other short-range wireless technologies, while household microwave ovens are also within this band. This results in a large number of users, and the compatibility and coexistence between devices need to be addressed. The 433MHz band is subject to interference from walkie-talkies, vehicle-mounted communication equipment, etc., and since it operates on a single frequency point, it cannot effectively resist multipath effects caused by obstruction, resulting in unreliable communication. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a medium-range wireless transmission method.

[0004] The objective of this invention is achieved through the following technical solution: a medium-range wireless transmission method, comprising the following steps:

[0005] S1: The terminal device sends a connection request frame through the main control frequency band, which includes the device ID and the RSSI signal strength value;

[0006] S2: After receiving the request, the gateway calculates the channel quality index based on the RSSI value. And dynamically allocate them to auxiliary frequency bands based on the results;

[0007] S3: The main control frequency band uses FSK modulation to transmit control commands, and the auxiliary frequency band uses QPSK-OFDM modulation to transmit data packets;

[0008] S4: During data transmission, channel parameters are collected every 10ms. If the packet loss rate is >5%, the auxiliary frequency band is switched to π / 4-DQPSK modulation transmission.

[0009] Preferably, in step S2, the channel quality index is calculated. It also includes the following steps:

[0010] S21: Filter the input RSSI value to obtain... ;

[0011] S22: Calculate path loss.

[0012] ;

[0013] in, For reference distance, This refers to the actual distance between the terminal and the gateway. For path loss at reference distance, This is the path loss index. The random variable caused by shadow fading follows a normal distribution. , The standard deviation of shadow fading.

[0014] S23: Calculate the environmental compensation value.

[0015] ;

[0016] in, This is the weather compensation value. This is the obstacle compensation value;

[0017] S24: Calculate the channel quality index ,

[0018] ;

[0019] ;

[0020] ;

[0021] in, The average packet loss rate over the past 60 seconds

[0022] Preferably, in step S2, when When, the link fails; when When the link quality level is poor, it is allocated to the main control frequency band; when When the link quality level is medium, it is allocated to the auxiliary frequency band; when When the link quality level is good, it is allocated to the auxiliary frequency band; when At that time, the link quality level was excellent, and it was allocated to the auxiliary frequency band.

[0023] Preferably, in step S3, the specific steps for transmitting control commands in the main control frequency band are as follows:

[0024] S31: Encapsulates instructions and converts digital signals into constant envelope analog signals;

[0025] S32: Perform Gaussian pulse shaping.

[0026] ;

[0027] ;

[0028] S33: After receiving the signal, the receiver performs delayed frequency discrimination and demodulation, and then performs clock synchronization.

[0029] Preferably, in step S33, the formula for delay-based frequency discrimination and demodulation is:

[0030] ;

[0031] in, This refers to the frequency discrimination sensitivity.

[0032] Preferably, in step S33, the specific steps for clock synchronization are as follows:

[0033] S33.1: Acquire signals at three time points.

[0034] ;

[0035] in, For bit period, For the first Each sampling time

[0036] Calculate the lead-lag voltage difference.

[0037] ;

[0038] Perform cumulative averaging.

[0039] ;

[0040] S33.2: Perform symbol verification.

[0041] ;

[0042] ;

[0043] S33.3: Update the phase of the sampling clock.

[0044] .

[0045] The present invention has the following advantages: The present invention calculates the channel quality index based on RSSI values. Based on the results, the frequency band is dynamically allocated to the auxiliary frequency band or the main control frequency band. The dual-band collaborative transmission mechanism is cleverly adopted, and the modulation mode is dynamically switched by real-time monitoring of channel quality, which improves the reliability of data packet transmission. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the process flow of a medium-range wireless transmission method. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0050] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0051] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0052] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0053] In this embodiment, as Figure 1 As shown, a mid-range wireless transmission method includes the following steps:

[0054] S1: The terminal device sends a connection request frame through the main control frequency band, which includes the device ID and the RSSI signal strength value;

[0055] S2: After receiving the request, the gateway calculates the channel quality index based on the RSSI value. And dynamically allocate them to auxiliary frequency bands based on the results;

[0056] S3: The main control frequency band uses FSK modulation to transmit control commands, and the auxiliary frequency band uses QPSK-OFDM modulation to transmit data packets;

[0057] S4: During data transmission, channel parameters are collected every 10ms. If the packet loss rate is >5%, the auxiliary frequency band is switched to π / 4-DQPSK modulation transmission. The channel quality index is calculated based on the RSSI value. Based on the results, the frequency band is dynamically allocated to the auxiliary frequency band or the main control frequency band. The dual-band collaborative transmission mechanism is cleverly adopted, and the modulation mode is dynamically switched by real-time monitoring of channel quality, which improves the reliability of data packet transmission.

[0058] Furthermore, in step S2, the channel quality index is calculated. It also includes the following steps:

[0059] S21: Filter the input RSSI value to obtain... Specifically, the main purpose of filtering the input RSSI value is to eliminate impulse noise.

[0060] S22: Calculate path loss.

[0061] ;

[0062] in, For reference distance, This refers to the actual distance between the terminal and the gateway. For path loss at reference distance, This is the path loss index. The random variable caused by shadow fading follows a normal distribution. , The standard deviation of shadow fading is given. Specifically, the path loss index is dynamically selected based on the environment; for example, it is 3.2 for urban areas and 2.7 for suburban areas. The typical value is 4.8 dB.

[0063] S23: Calculate the environmental compensation value.

[0064] ;

[0065] in, This is the weather compensation value. This is the obstacle compensation value;

[0066] S24: Calculate the channel quality index ,

[0067] ;

[0068] ;

[0069] ;

[0070] in, This represents the average packet loss rate over the past 60 seconds. Specifically, in step S23, the weather is sunny. The value is 0; the weather is rainy. The value is 2.3; the weather is snowy. The value is 4.1; the weather is foggy. The value is 1.2. When there is no obstruction, The value is 0; when the obstacle is metal, The value is 8.7; when the obstacle is concrete, The value is 6.2; when the obstacle is glass, It is 3.1.

[0071] Furthermore, in step S2, when When, the link fails; when When the link quality level is poor, it is allocated to the main control frequency band; when When the link quality level is medium, it is allocated to the auxiliary frequency band; when When the link quality level is good, it is allocated to the auxiliary frequency band; when At that time, the link quality level was excellent, and it was allocated to the auxiliary frequency band.

[0072] In this embodiment, the specific steps for transmitting control commands in the main control frequency band in step S3 are as follows:

[0073] S31: Encapsulates instructions and converts digital signals into constant envelope analog signals;

[0074] S32: Performs Gaussian pulse shaping, its main function is to compress signal bandwidth and suppress adjacent channel interference.

[0075] ;

[0076] ;

[0077] S33: After receiving the signal, the receiving end performs delayed frequency discrimination and demodulation, and then synchronizes the clock. Specifically, in step S33, the formula for delayed frequency discrimination and demodulation is:

[0078] ;

[0079] in, To improve frequency discrimination sensitivity, its main function is to convert frequency changes into voltage changes and recover the original bits. Further, in step S33, the main function of clock synchronization is to eliminate sampling clock offset and reduce the bit error rate. The specific steps of clock synchronization are as follows:

[0080] S33.1: Acquire signals at three time points.

[0081] ;

[0082] in, For bit period, For the first Each sampling time

[0083] Calculate the lead-lag voltage difference.

[0084] ;

[0085] Perform cumulative averaging.

[0086] ;

[0087] S33.2: Perform symbol verification.

[0088] ;

[0089] ;

[0090] S33.3: Update the phase of the sampling clock.

[0091] .

[0092] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A medium-range wireless transmission method, characterized in that: Includes the following steps: S1: The terminal device sends a connection request frame through the main control frequency band, which includes the device ID and the RSSI signal strength value; S2: After receiving the request, the gateway calculates the channel quality index based on the RSSI value. And dynamically allocate them to auxiliary frequency bands based on the results; S3: The main control frequency band uses FSK modulation to transmit control commands, and the auxiliary frequency band uses QPSK-OFDM modulation to transmit data packets; S4: During data transmission, channel parameters are collected every 10ms. If the packet loss rate is >5%, the auxiliary frequency band is switched to π / 4-DQPSK modulation transmission. In step S2, the channel quality index is calculated. It also includes the following steps: S21: Filter the input RSSI value to obtain... ; S22: Calculate path loss. ； in, For reference distance, This refers to the actual distance between the terminal and the gateway. For path loss at reference distance, This is the path loss index. The random variable caused by shadow fading follows a normal distribution. , The standard deviation of shadow fading. S23: Calculate the environmental compensation value. ； in, This is the weather compensation value. This is the obstacle compensation value; S24: Calculate the channel quality index , ； ； ； in, The average packet loss rate over the past 60 seconds; In step S2, when When, the link fails; when When the link quality level is poor, it is allocated to the main control frequency band; when When the link quality level is medium, it is allocated to the auxiliary frequency band; when When the link quality level is good, it is allocated to the auxiliary frequency band; when At that time, the link quality level is excellent, and it is allocated to the auxiliary frequency band; In step S3, the specific steps for transmitting control commands in the main control frequency band are as follows: S31: Encapsulates instructions and converts digital signals into constant envelope analog signals; S32: Perform Gaussian pulse shaping. ； ； S33: After receiving the signal, the receiver performs delayed frequency discrimination and demodulation, and then performs clock synchronization; In step S33, the formula for delay-based frequency discrimination and demodulation is: ； in, For frequency discrimination sensitivity; In step S33, the specific steps for clock synchronization are as follows: S33.1: Acquire signals at three time points. ； in, For bit period, For the first Each sampling time Calculate the lead-lag voltage difference. ； Perform cumulative averaging. ； S33.2: Perform symbol verification. ； ； S33.3: Update the phase of the sampling clock. 。

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