Channel activity detection method and device based on nonlinear chirp spread spectrum signal, and medium

Abstract

The invention discloses a channel activity detection method and device based on a nonlinear chirp spread spectrum signal and a medium, and the method comprises the steps: designing a beacon of a global channel occupancy matrix based on gateway information, and periodically transmitting the beacon to a node; designing a channel occupation matrix based on terminal node historical channel access information; combining the global channel occupancy matrix and the channel occupancy matrix at the node in an element weighted sum mode to obtain a transmission channel information joint matrix; an access control strategy based on a distributed frame spacing mechanism and a random back-off mechanism is designed at a node, transmission parameters are reasonably selected by using a joint matrix, and collision-free transmission of multi-node data is carried out. According to the invention, the information combination between the gateway and the terminal node is utilized, the node information collision is effectively avoided, the energy consumption of the network is saved, and the implementation method is simple and clear and has practical value.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communication, and particularly relates to a channel activity detection method, device and medium based on non-linear chirp spread spectrum signals. Background Art

[0002] With the wide application of Internet of Things technology in fields such as industrial monitoring, smart agriculture, and smart grid, wireless communication systems need to achieve efficient channel access and resource management in high-density node deployment and strong electromagnetic interference environments. Traditional linear chirp spread spectrum (CSS) technology has been widely used in low-power wide-area networks (LPWANs) due to its advantages of anti-multipath interference and high spectrum utilization. However, it still faces the following key problems in practical applications: 1) Insufficient channel bit error rate and sensitivity The spectrum structure of linear chirp signals is fixed, and its anti-multipath interference ability depends on the spreading gain. However, in complex electromagnetic environments (such as multipath reflection, Rayleigh fading), the time-frequency offset caused by signal superposition will significantly reduce the signal-to-noise ratio (SNR), thereby increasing the bit error rate. Traditional channel sensing methods based on energy detection or matched filtering are difficult to accurately distinguish weak signals from noise, resulting in a high probability of channel misjudgment.

[0003] 2) Poor dynamic channel adaptability The frequency modulation slope of linear chirp signals is fixed and cannot flexibly adapt to dynamic channel changes (such as fast fading or multipath delay spread). In the scenario of multi-node shared channels, traditional methods need to sacrifice detection time or increase the sampling rate to improve accuracy, which conflicts with the low-power requirements of Internet of Things devices.

[0004] 3) Low multi-node cooperation efficiency Existing multi-node channel access protocols (such as ALOHA, CSMA) rely on single-point channel state sensing and lack an inter-node cooperation mechanism, resulting in increased channel competition and further deterioration of system throughput and reliability.

[0005] The innovation of the present invention lies in proposing a channel activity detection method, device and medium based on non-linear chirp spread spectrum signals. By introducing a non-linear frequency modulation term (such as quadratic frequency modulation) to expand the time-frequency characteristics of the signal, the channel resolution and anti-interference ability are significantly improved, thereby reducing the bit error rate and optimizing the channel sensing efficiency. At the same time, combined with a distributed node cooperation mechanism, real-time sharing and joint detection of dynamic channel states are realized, providing reliable communication guarantees for high-density Internet of Things networks. Summary of the Invention

[0006] The present invention proposes a channel activity detection method, device and medium based on non - linear chirp spread - spectrum signals. The present invention can effectively reduce the collision probability and save the energy consumption of devices. The present invention uses the Distributed Inter - Frame Space (DIFS) mechanism in the Distributed Coordination Function (DCF), and uses a fixed number of Channel Activity Detectors (CADs) to complete the time slots of each Distributed Inter - Frame Space mechanism. In order to effectively meet the requirements of low collision and low energy consumption, the present invention adds an adaptive mechanism for the terminal to dynamically select a suitable CH / SF combination for transmission. At the same time, the present invention also proposes a method for analyzing the global view of the gateway to minimize access collisions and energy consumption.

[0007] The object of the present invention is achieved by the following technical solutions: A channel activity detection method based on non - linear chirp spread - spectrum signals, comprising the following steps: Step 1, at the gateway, define a non - linear chirp beacon for the global channel occupancy matrix, and the node extracts the time - frequency features through matched filtering and periodically sends them to the network nodes; Step 2, at the terminal node, update the local channel occupancy matrix based on historical detection data, correct the false detection probability using the cross - correlation of non - linear chirps, and define a channel occupancy matrix reflecting the congestion degree of the channel / spreading factor; Step 3, at the terminal node, combine the global channel occupancy matrix and the channel occupancy matrix by the element weighted sum method to obtain a joint matrix that fully reflects the transmission channel information; Step 4, each node is based on the access control strategy of the Distributed Inter - Frame Space mechanism, and designs a fixed number of channel activity detectors to complete the time slot detection of each Distributed Inter - Frame Space mechanism; perform channel activity detection on the time slots of the Distributed Inter - Frame Space mechanism. When the detection results are all idle, randomly generate a back - off number and enter the random back - off mechanism stage; in the random back - off mechanism stage, detect the channel availability through the channel activity detector, and gradually decrease the value of the back - off number. When the final back - off number is 0, the node normally transmits data; Step 5, for the nodes applying for access in the same stage, adjust the channel / spreading factor according to the joint matrix obtained in Step 3, and finally complete the access control of multiple nodes according to Step 4, and finally realize channel activity detection.

[0008] Further, in Step 1, the global channel occupancy matrix is a matrix with the size of the number of channels × the number of spreading factors, where each matrix element represents the competition level under the given channel / spreading factor condition; the global channel occupancy matrix is transmitted through a predefined feedback channel using a time - division - multiplexed beacon, and the beacon needs to contain the ID of the gateway sending the beacon to handle the situation where a node receives overlapping coverage from two or more gateways.

[0009] Furthermore, in step 2, the channel occupancy matrix is a matrix with the size of the number of channels × the number of spreading factors, where each matrix element represents the historical utilization rate under the given channel / spreading factor condition; the channel occupancy matrix utilizes the information of the failed distributed inter-frame mechanism and the random backoff operation to achieve indirect channel detection; each node maintains historical information about the congestion degree of the past detected channel / spreading factor combinations; the channel occupancy matrix is updated by the channel occupancy adaptive algorithm after each failed channel activity detection. The channel occupancy adaptive algorithm collects the information of each failed channel activity detection, judges the congestion state information data set, and adjusts and updates the congestion state information data set at an appropriate ratio according to the proportion of the number of times of channel occupancy detected by the channel activity in the total number of detections.

[0010] Furthermore, in step 3, the process of combining the global channel occupancy matrix and the channel occupancy matrix adopts the weighted sum of the matrix elements of the two matrices.

[0011] Furthermore, in step 4, for each node, when all channel activity detectors in a time slot of a distributed inter-frame interval mechanism report as idle, a random backoff number is generated and the node enters the random backoff mechanism stage; in the random backoff mechanism stage, when the channel activity detector of the node reports the channel as idle each time, the backoff number is decremented by 1; the node continuously checks the availability of the channel. If the channel is occupied, the node is reset to the distributed inter-frame interval mechanism state. In this case, the node needs to wait for an idle channel again and resume the countdown of the backoff number; finally, when the backoff number is decremented to zero, the node starts to transmit data normally.

[0012] Furthermore, in step 5, during a certain node performing step 4, if another node senses that the channel is busy according to the combined matrix in step 3, it will reselect a better channel / spreading factor channel, continue to detect according to the process of step 4. If the detection is successful, it will send normally; otherwise, it will update the combined matrix and then select again.

[0013] The present invention also provides a channel activity detection device based on a non-linear chirp spread spectrum signal, including one or more processors for implementing a channel activity detection method based on a non-linear chirp spread spectrum signal as described above.

[0014] The present invention also provides a readable storage medium, on which a program is stored. When the program is executed by a processor, it implements a channel activity detection method based on a non-linear chirp spread spectrum signal as described above.

[0015] The present invention has the following advantages compared with the prior art: 1. The present invention effectively avoids channel conflicts by using the Distributed Inter-Frame Space (DIFS) mechanism and the Back-Off (BO) mechanism, improving the Packet Reception Rate (PRR) and network throughput. Compared with the traditional ALOHA protocol, it can maintain a PRR of up to 90% when communication demands increase, and brings a 1.5-fold improvement in throughput.

[0016] 2. Based on the unique star network topology characteristics of the non-linear chirp spread spectrum signal, the present invention collaborates nodes with the gateway. By the gateway regularly broadcasting global channel information and nodes combining local information to guide channel selection before transmission, the network performance is further improved, and a more balanced channel load selection is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flowchart of a channel activity detection method based on non-linear chirp spread spectrum signal of the present invention.

[0018] Figure 2 It is a schematic structural diagram of a channel activity detection device based on non-linear chirp spread spectrum signal of the present invention.

[0019] Figure 3 It is a working principle diagram of a simulation example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The technical solutions and effects of the present invention will be further described in detail with reference to the accompanying drawings below.

[0021] Before introducing the channel activity detection method based on non-linear chirp spread spectrum signal provided by the present invention, the concept of Channel Activity Detection (CAD) will be briefly introduced.

[0022] As a key technology of the Carrier Sense Multiple Access (CSMA) protocol, Channel Activity Detection (CAD) has always been one of the focuses of academic research. Existing LoRa node chips all have the function of CAD. By listening for 2 - 3 symbol lengths and using coherent demodulation signals to determine whether it is the data of the current coding and channel, thus determining whether the channel is occupied, it has the characteristics of low power consumption and low collision probability.

[0023] The above channel activity detection method is usually applied to LoRa ad-hoc or private networks. For networks transmitting non-linear chirp signals, traditional methods often use ALOHA random access, facing a series of challenges such as high collision probability and low transmission efficiency. To address the above challenges, the present invention proposes a channel activity detection method based on non-linear chirp spread spectrum signal by coordinating the information synchronization and fusion of terminal nodes and the gateway, using the Distributed Inter-Frame Space (DIFS) mechanism and the Back-Off (BO) mechanism. Please refer to Figure 1 , the implementation steps of the present invention are as follows: Step 1: At the gateway, design a beacon based on the overall channel utilization status of the channel occupancy matrix Ψ, and periodically send the beacon to network nodes.

[0024] Among them, the global channel occupancy matrix Ψ is a matrix of size N CH ×N SF where each matrix element Ψ CH,SF represents the competition level under a given channel / spreading factor (CH / SF) condition, and N CH and N SF represent the values of CH and SF respectively. The matrix Ψ can reflect the current occupancy of the channel. The matrix Ψ is transmitted through a predefined feedback channel using time-division transmission of the beacon. Considering that there is no strict clock synchronization between nodes and clock drift may cause nodes to fail to receive the beacon normally, the gateway needs to send the beacon multiple times continuously to increase the reception probability of the terminal node. The ID of the gateway needs to be included in the beacon to handle the situation where a node receives overlapping coverage from two or more gateways.

[0025] Step 2: At the terminal node, update the local channel occupancy matrix Γ based on historical detection data, correct the false detection probability using the cross-correlation of non-linear chirps, and define a channel occupancy matrix Γ that reflects the congestion level of the channel / spreading factor (CH / SF combination). The channel occupancy matrix Γ is a matrix of size N CH ×N SF where each element γ CH,SF represents the historical utilization rate under a given CH / SF condition. The matrix Γ utilizes the information of the failed distributed frame interval mechanism and random backoff operations to achieve indirect channel detection. Each node maintains historical information about the congestion degree of the CH / SF combinations detected in the past. The matrix Γ is updated at after each failed channel activity detection, where the dataset α of the congestion status information of the node is defined as the update ratio, CAD busy is the number of times the channel activity is detected to occupy the channel, and CAD total is the total number of detections. To ensure a high correlation of the recently sensed channel, set α = 0.85.

[0026] Step 3: At the terminal node, combine the global channel occupancy matrix Ψ and the channel occupancy matrix Γ using the element weighted sum method to obtain a joint matrix that fully reflects the transmission channel information. The joint matrix effectively utilizes the global view provided by the gateway while retaining the historical characteristics of the node itself.

[0027] For a node, there are CH / SFs for which channel activity detection has not been performed. In the Γ matrix, γ CH,SFSome elements of it remain empty and cannot correctly reflect the channel state. Compensating the local view at the node through the global channel view of the gateway can effectively eliminate the empty elements of the Γ matrix. In the process of merging the Ψ and Γ matrices, an element weighted sum strategy is adopted, where the weight of the elements in Γ is 0.7 and the weight of the elements in Ψ is 0.3. On the premise of retaining the historical information of the node itself, it can better reflect the combined state of all CH / SF in real time.

[0028] Step 4: Each node is based on the access control strategy of the Distributed Inter-Frame Space (DIFS) mechanism and designs a fixed number of Channel Activity Detectors (CADs) to complete the detection of each DIFS time slot. CAD detection is performed on the DIFS time slot. When the detection results are all idle, a random backoff number (N BO value) is generated and the node enters the random backoff mechanism stage (BO stage). In the BO stage, the channel availability is detected through CAD, and the value of N BO is changed. Finally, when N BO is 0, the node transmits data normally.

[0029] Among them, for a single terminal node, it is necessary to confirm the state of the CH / SF for each transmission. Only when it is in the idle state can it transmit. The confirmation process introduces the Distributed Inter-Frame Space (DIFS) mechanism, which is used to control the node to wait for a period of time interval before transmitting data. When the channel is detected to be idle within the time slot of the distributed inter-frame space mechanism, the node will enter the transmission state, otherwise it will continue to wait. When all CAD reports of a time slot of the distributed inter-frame space mechanism are idle, it enters the BO stage. In the random backoff mechanism stage, a random backoff value N BO is generated, and its value range is [4, 64]. Each time the node's CAD reports that the channel is idle, the value of N BO is decremented by 1. The randomized initial backoff value N BO reduces the possibility of collision of two or more frames. The node continuously checks the channel availability. If the channel is occupied, the node is reset to the DIFS state. In this case, the node needs to wait for an idle channel again and resume the countdown of N BO . Finally, when N BO is decremented to zero, the node starts to transmit data normally.

[0030] Step 5: For the nodes applying for access in the same stage, the CH / SF is adjusted according to the joint matrix λ obtained in Step 3. Finally, according to Step 4, the access control of multiple nodes is completed, and finally the CAD detection is realized.

[0031] Among them, considering the scenario where multiple terminal nodes select the same CH / SF, during step 4 at a single node, another node senses the channel state based on the channel information in step 3. When it is determined that the channel state is busy, a better-performing CH / SF channel in the combining matrix will be reselected and the detection will continue according to the process of step 4. If the detection is successful, it will be sent normally; otherwise, the combining matrix information will be updated and then selected again. From the perspective of the node, the number of CADs required for each transmission and the related time / energy consumption are reduced, avoiding channel collisions.

[0032] According to the above corresponding steps, the channel activity detection method based on the non-linear chirp spread spectrum signal can be completed.

[0033] On the one hand, the present invention adopts the distributed inter-frame space (DIFS) mechanism and the back-off (BO) mechanism, effectively solving the channel conflict problem. Compared with the traditional ALOHA protocol, the packet reception rate (PRR) and network throughput are improved. On the other hand, the present invention realizes the collaborative work between the node and the gateway. By the gateway regularly broadcasting the global channel information and combining with the local information of the node, it guides the channel selection before transmission, further improving the network performance and achieving a more balanced channel load selection.

[0034] See Figure 2 , a channel activity detection device based on the non-linear chirp spread spectrum signal provided by an embodiment of the present invention includes one or more processors for implementing a channel activity detection method based on the non-linear chirp spread spectrum signal in the above embodiment.

[0035] An embodiment of a channel activity detection device based on the non-linear chirp spread spectrum signal of the present invention can be applied to any device with data processing capabilities, and the any device with data processing capabilities can be a device or apparatus such as a computer. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. Taking software implementation as an example, as a logically meaningful device, it is formed by the processor of any device with data processing capabilities where it is located reading the corresponding computer program instructions in the non-volatile memory into the memory for operation. From the hardware level, as Figure 2 shown, it is a hardware structure diagram of any device with data processing capabilities where a channel activity detection device based on the non-linear chirp spread spectrum signal of the present invention is located. In addition to Figure 2 the shown processor, memory, network interface, and non-volatile memory, any device with data processing capabilities where the device in the embodiment is located usually also includes other hardware according to the actual functions of the any device with data processing capabilities, which will not be elaborated here.

[0036] The implementation processes of the functions and roles of each unit in the above device are specifically described in the implementation processes of the corresponding steps in the above method, and will not be elaborated here.

[0037] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered that the scope described in this specification.

[0038] The embodiments of the present invention also provide a readable storage medium, on which a program is stored. When the program is executed by a processor, it implements a method for detecting channel activity based on a non-linear chirp spread spectrum signal in the above embodiments.

[0039] The readable storage medium may be an internal storage unit of any device with data processing capabilities described in any of the foregoing embodiments, such as a hard disk or memory. The readable storage medium may also be an external storage device, such as a plug-in hard disk, a Smart Media Card (SMC), an SD card, a Flash Card, etc. equipped on the device. Further, the readable storage medium may also include both an internal storage unit of any device with data processing capabilities and an external storage device. The readable storage medium is used to store the computer program and other programs and data required by any device with data processing capabilities, and may also be used to temporarily store data that has been output or will be output.

[0040] The terms used in one or more embodiments of this specification are only for the purpose of describing specific embodiments, and are not intended to limit one or more embodiments of this specification. The singular forms "a", "the", and "said" used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0041] It should be understood that although the terms first, second, third, etc. may be used in one or more embodiments of this specification to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of this specification, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0042] The following further describes the effect of the method proposed by the present invention in combination with simulation examples.

[0043] Simulation example: As Figure 3 shown, here, the annotation will be illustrated by taking the channel detection process of two nodes and a gateway in the same network in the network topology as an example.

[0044] (1) Node A opens the transmission window, notifies the gateway of the data transmission requirement, and configures a series of parameters such as CH / SF.

[0045] (2) The gateway receives the transmission requirement from Node A and sends its own global channel occupancy matrix Ψ and its number information to Node A.

[0046] (3) Node A receives the information from the gateway, performs weighted update with its own local channel occupancy matrix Γ, and reconfigures the parameters. In this example, CH = 1 and SF = 7.

[0047] (4) Node A performs channel activity detection in the DIFS stage. When all CAD reports for a time slot of the distributed frame interval mechanism are idle, it enters the random backoff mechanism stage and generates a random backoff value N BO , in this example, N BO = 2.

[0048] (5) In the random backoff mechanism stage of Node A, each time the CAD reports that the channel is idle, the value of N BO decreases by 1. Finally, when N BO decreases to zero, Node A opens the transmission window and starts to normally transmit data to the gateway.

[0049] (6) Node B performs parameter configuration before receiving the information from the gateway. In this example, CH = 1 and SF = 7, and updates after receiving the gateway information. Since Node A selected CH = 1 and SF = 7 before Node B, the selected channel is busy at this time. Therefore, Node B reconfigures the parameters using the obtained channel information. In this example, CH = 2 and SF = 7.

[0050] (7) Node B performs channel activity detection in the DIFS stage. When all CAD reports for a time slot of the distributed frame interval mechanism are idle, it enters the random backoff mechanism stage and generates a random backoff value N BO , in this example, N BO = 3.

[0051] (8) In the random backoff mechanism stage of Node B, each time the CAD reports that the channel is idle, the value of N BO decreases by 1. Finally, when N BO decreases to zero, Node B opens the transmission window and starts to normally transmit data to the gateway.

[0052] The above example process constructs a topology on ns-3 and implements the entire process using a Python script. The experimental results show that, compared with the traditional ALOHA method, it can effectively reduce the collision probability of nodes, improve the network throughput while reducing the energy consumption of nodes.

[0053] The above is only the preferred embodiment of the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A channel activity detection method based on non - linear chirp spread - spectrum signals, characterized in that, It includes the following steps: Step 1: At the gateway, define a non-linear chirp beacon for the global channel occupancy matrix. Nodes extract time-frequency features through matched filtering and periodically send them to network nodes; Step 2: At the terminal node, update the local channel occupancy matrix based on historical detection data, correct the false detection probability using the cross-correlation of non-linear chirps, and define a channel occupancy matrix reflecting the congestion degree of the channel / spreading factor; Step 3: At the terminal node, combine the global channel occupancy matrix and the channel occupancy matrix using the element weighted sum method to obtain a joint matrix that fully reflects the transmission channel information; Step 4: Each node is based on the access control strategy of the distributed frame interval mechanism and designs a fixed number of channel activity detectors to complete the time slot detection of each distributed frame interval mechanism; Channel activity detection is performed on the time slots of the distributed frame interval mechanism. When the detection results are all idle, a random backoff number is randomly generated and enters the random backoff mechanism stage; In the random backoff mechanism stage, the channel availability is detected by the channel activity detector, and the value of the backoff number is changed by decreasing one by one. When the backoff number finally reaches 0, the node normally transmits data; Step 5: For nodes applying for access in the same stage, adjust the channel / spreading factor according to the joint matrix obtained in Step 3. Finally, according to Step 4, complete the access control of multiple nodes and finally realize channel activity detection.

2. The channel activity detection method based on non-linear chirp spread spectrum signals according to claim 1, wherein In Step 1, the global channel occupancy matrix is a matrix with the size of the number of channels × the number of spreading factors, where each matrix element represents the competition level under the given channel / spreading factor condition; The global channel occupancy matrix is transmitted through a predefined feedback channel using a time-division transmission beacon. The beacon needs to include the ID of the gateway sending the beacon to handle the situation where a node receives overlapping coverage from two or more gateways.

3. A channel activity detection method based on a non-linear chirp spread spectrum signal according to claim 1, characterized in that, In Step 2, the channel occupancy matrix is a matrix with the size of the number of channels × the number of spreading factors, where each matrix element represents the historical utilization rate under the given channel / spreading factor condition; The channel occupancy matrix uses the information of the failed distributed frame interval mechanism and random backoff operations to achieve indirect channel detection; Each node maintains historical information about the congestion degree of the past detected channel / spreading factor combinations; The channel occupancy matrix is updated with a channel occupancy adaptive algorithm after each failed channel activity detection. The channel occupancy adaptive algorithm judges the congestion state information dataset by collecting the information of each failed channel activity detection, and adjusts and updates the congestion state information dataset in an appropriate proportion according to the ratio of the number of times of channel occupancy detected by the channel activity detection to the total number of detections.

4. A channel activity detection method based on a non-linear chirp spread spectrum signal according to claim 1, characterized in that, In Step 3, the process of combining the global channel occupancy matrix and the channel occupancy matrix uses the weighted sum of the matrix elements of the two matrices.

5. A channel activity detection method based on a non-linear chirp spread spectrum signal according to claim 1, characterized in that In step 4, for each node, when all channel activity detectors of a time slot of a distributed frame interval mechanism report idle, a random backoff number is generated and the node enters the random backoff mechanism stage; in the random backoff mechanism stage, each time the channel activity detector of the node reports that the channel is idle, the backoff number is decremented by 1; the node continuously checks the availability of the channel. If the channel is occupied, the node is reset to the distributed frame interval mechanism state. In this case, the node needs to wait for an idle channel again and resume the countdown of the backoff number; finally, when the backoff number is decremented to zero, the node starts to transmit data normally.

6. The channel activity detection method based on non-linear chirp spread spectrum signals according to claim 1, characterized in that In step 5, during a certain node performing step 4, if another node senses that the channel is busy according to the joint matrix of step 3, it will reselect a better channel / spread factor channel and continue to detect according to the process of step 4. If the detection is successful, it will transmit normally; otherwise, it will update the joint matrix and then select again.

7. A channel activity detection device based on a non-linear chirp spread spectrum signal, characterized in that, Comprising one or more processors for implementing a channel activity detection method based on a non-linear chirp spread spectrum signal according to any one of claims 1-6.

8. A readable storage medium, characterized in that, Stored thereon is a program which, when executed by the processor, implements a channel activity detection method based on a non-linear chirp spread spectrum signal according to any one of claims 1-6.

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