Channel access method, system and device for cross-medium communication and medium

Abstract

The invention relates to the technical field of cross-medium communication, and discloses a channel access method, system and equipment for cross-medium communication and a medium, and the method comprises the following steps: a physical layer supports selection of multiple modulation modes to adapt to signal diffusion characteristics under different medium conditions; a request sending window mechanism is introduced into a data link layer, communication time slots are divided in combination with a time slot ALOHA protocol, efficient channel access and conflict management are achieved, and the conflict probability caused by propagation delay is reduced; a forward error correction coding mechanism is adopted in a transmission control layer, so that a receiving end can correct bit errors or erasure states without retransmission. Through collaborative design of a physical layer, a data link layer and a transmission control layer, the method provided by the invention effectively improves the stability, reliability and transmission efficiency of a cross-medium communication system in a complex and changeable environment.

Description

Technical Field

[0001] The present invention relates to the field of cross-media communication technology, and in particular to a channel access method, system, device and medium for cross-media communication. Background Art

[0002] With the rapid development of 6G wireless network technology, global universal access, ultra-high-speed connectivity, and low-latency communications have become core goals of future network development. Against this backdrop, new application scenarios such as air-to-water, air-to-underground, and air-to-in-body communications are gaining attention and becoming a key driver for expanding wireless communications into a wider range of fields. However, due to the significant differences in electromagnetic properties between different media (such as air, water, soil, and biological tissue), signals propagating across these media face severe attenuation, delay, and interference, posing significant challenges to the stability and reliability of communication systems.

[0003] Traditional wireless communication systems are primarily designed for air channels, assuming high signal propagation speeds, stable path loss, and relatively simple multipath effects. However, in a multi-medium environment, signals can encounter problems such as a sudden drop in propagation speed, increased energy absorption, and a dramatic increase in path loss when crossing interfaces between different media. These issues are particularly pronounced in media with high dielectric constants or high absorptivity. Furthermore, reflection, refraction, and scattering between different media exacerbate channel fluctuations, further increasing the instability of communication links.

[0004] From a physical layer perspective, existing cross-media communication technologies often use modulation methods with strong interference resistance, such as Chirp Spread Spectrum (CSS), to improve signal penetration and robustness in complex environments. However, these methods are still insufficient when faced with AM broadcast band interference, inter-symbol interference caused by mechanical vibration, and high-erasure rate channels. In particular, they struggle to maintain stable data transmission quality in low signal-to-noise ratio conditions. Furthermore, traditional narrowband modulation methods perform poorly in high-attenuation environments, and the conventional additive white Gaussian noise channel model is no longer applicable. Actual channels are more like harsh environments with high bit error rates and high packet loss rates.

[0005] At the data link layer, traditional carrier-sense multiple access mechanisms (such as CSMA / CA) struggle to operate effectively due to significant differences in signal propagation speeds across different media. Uncertainty in propagation delay prevents nodes from timely detecting the transmission activity of other nodes, leading to the hidden node problem and numerous collisions. Furthermore, multipath effects at media interfaces further exacerbate the unpredictability of channel states, reducing the effectiveness of random backoff mechanisms and impairing overall network throughput.

[0006] High bit error rates and unstable feedback paths at the transmission control layer severely limit the effectiveness of automatic repeat request mechanisms. Frequent retransmissions not only waste limited channel resources but can also cause link congestion and accumulated delays, ultimately impacting the efficiency of the entire communication system. Furthermore, the highly dynamic and uncertain nature of cross-media environments, such as changes in underwater salinity, fluctuations in soil moisture, and real-time variations in human tissue parameters, can cause rapid evolution of channel conditions, requiring communication protocols to possess stronger adaptability.

[0007] In summary, current cross-media communication systems face many technical bottlenecks at the physical layer, link layer, and transport layer. There is an urgent need for an adaptive communication protocol system that can adapt to complex and changing environments to achieve efficient, reliable, and stable cross-media data transmission. Summary of the Invention

[0008] In view of the above existing problems, the present invention is proposed.

[0009] Therefore, the present invention provides a channel access method, system, device and medium for cross-media communication to solve the problem that existing cross-media communication technology is sensitive to signal attenuation and propagation delay at the physical level, the data link layer has difficulty in handling uncertainty conflicts caused by multipath effects, and the transmission control layer is inefficient due to high bit error rate and unstable feedback mechanism. These problems jointly restrict the stability and reliability of the communication system.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0011] In a first aspect, the present invention provides a channel access method for cross-medium communication, comprising:

[0012] A linear frequency modulation spread spectrum modulation technique is adopted at the physical layer, a first symbol type is defined by controlling the rise, fall and sweep time of the linear frequency modulation, and a modulated signal is generated;

[0013] Performing a first operation on the modulated signal at the receiving end to determine the starting position of the data packet, and performing a second operation on subsequent symbols to obtain a demodulated symbol state;

[0014] Introducing the request-to-send window mechanism at the data link layer and combining it with the slotted ALOHA protocol to divide communication time slots, thus achieving efficient channel access and conflict management.

[0015] A forward error correction coding mechanism is adopted in the transmission control layer to enable the receiving end to correct bit errors or erasure states without the need for retransmission.

[0016] As a preferred solution of the channel access method for cross-medium communication described in the present invention, the first symbol type includes long up-chirp, short up-chirp and short down-chirp.

[0017] As a preferred solution of the channel access method for cross-medium communication according to the present invention, the step of obtaining the demodulated symbol state includes:

[0018] performing an operation on an input signal using the long up-chirp, and determining a starting position of the data packet when a correlation peak exceeds a first threshold;

[0019] Calculate the short upper chirp and the short lower chirp one by one on subsequent symbols to obtain a first peak value and a second peak value;

[0020] If the first peak value exceeds the second peak value and the first peak value is greater than a second threshold, the symbol state is bit 1; if the second peak value exceeds the first peak value and the second peak value is greater than a second threshold, the symbol state is bit 0;

[0021] If none of the conditions are met, the symbol is erased due to strong interference or noise.

[0022] The beneficial effect of this preferred technical solution is: supporting multiple modulation mode selections to adapt to signal diffusion characteristics under different medium conditions.

[0023] As a preferred solution of the channel access method for cross-media communication described in the present invention, the cross-media channel is modeled as a binary erasure channel, and the transmitted bits are correctly received or erased with a first probability.

[0024] As a preferred solution of the channel access method for cross-media communication described in the present invention, in which: in the cross-media communication system, the node is equipped with a dual front-end module, including an acoustic signal front-end and an electromagnetic wave signal front-end, and during cross-media communication, the acoustic signal or the electromagnetic wave signal is selected for data transmission according to the propagation characteristics of the medium.

[0025] As a preferred solution of the channel access method for cross-media communication according to the present invention, the processing of the data link layer includes:

[0026] A request-to-send window mechanism is introduced. Before transmitting data, a node broadcasts a request-to-send signal. When surrounding nodes receive the request-to-send signal, they are informed that the channel will be occupied.

[0027] The communication time is divided into uniform time slots in combination with the slotted ALOHA protocol. A node only sends the request to send signal at the beginning of a time slot. If it detects the request to send signal sent by other nodes, it will try to transmit again after delaying a random number of time slots to reduce the probability of collision.

[0028] The beneficial effect of this preferred technical solution is that the probability of conflict caused by propagation delay is reduced by introducing a request to send (RTS) mechanism and centralized time slot synchronous access.

[0029] As a preferred solution of the channel access method for cross-media communication according to the present invention, the processing of the transmission control layer includes:

[0030] Perform polarization transformation on multiple channels to divide the channels into high-reliability channels and low-reliability channels;

[0031] The transmitting end performs polar code encoding on the data, maps the information bits to the high-reliability channel, and fills the low-reliability channel with fixed frozen bits;

[0032] Based on the characteristics of binary erasure channels, a polarization-coded redundant structure is embedded in the transmitted data packets.

[0033] The receiving end recovers the original data with bit erasure or bit errors through the polarization decoding process.

[0034] The beneficial effect of this preferred technical solution is that it adopts a flexible forward error correction coding mechanism, taking polar codes as an example, which can improve the data recovery success rate even in a high erasure and high bit error rate environment.

[0035] In a second aspect, the present invention provides a channel access system for cross-medium communication, comprising:

[0036] A linear frequency modulation spread spectrum module is configured to employ linear frequency modulation spread spectrum modulation technology at the physical layer, define a first symbol type by controlling the rise, fall, and sweep times of the linear frequency modulation, and generate a modulated signal; perform a first operation on the modulated signal at the receiving end to determine the starting position of the data packet, and perform a second operation on subsequent symbols to obtain a demodulated symbol state;

[0037] The media access control module is used to introduce a request-to-send window mechanism at the data link layer and divide communication time slots in combination with the slotted ALOHA protocol to achieve efficient channel access and conflict management;

[0038] The polar code encoding module is configured to employ a forward error correction coding mechanism in the transmission control layer to enable the receiving end to correct bit errors or erasure states without the need for retransmission.

[0039] In a third aspect, the present invention provides an electronic device comprising a memory and a processor; the memory is used to store computer-executable instructions, and the processor implements the steps of a channel access method for cross-media communication when executing the computer-executable instructions.

[0040] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of a channel access method for cross-media communication.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] ① This invention effectively improves signal interference resistance by introducing an adaptive protocol based on technologies such as linear frequency modulation spread spectrum (CSS), particularly enabling a low bit error rate (BER) in cross-media communications. Experimental results demonstrate that CSS offers stronger interference resistance under low signal-to-noise ratio (SNR) conditions compared to traditional ASK and FSK modulation techniques, significantly improving communication stability and reliability and ensuring efficient data transmission.

[0043] ② Compared with existing cross-media communication technologies, the present invention exhibits superior communication performance in a variety of media, especially in fresh water, sea water, soil and other media, where the communication depth and range are superior to traditional technologies. This makes the system widely applicable in Internet of Things applications and meets the needs of sensor networks for long-distance and stable transmission.

[0044] ③ This invention introduces the CSMA / CA and RTS mechanisms at the data link layer, combined with the slotted ALOHA protocol, to achieve more efficient channel access and conflict management. This improved channel access control method allows multiple nodes to avoid channel conflicts in complex environments, reducing packet loss and improving network throughput and reliability. In particular, in multi-node environments, the system's successful transmission rate is significantly improved, ensuring smooth cross-media communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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.

[0046] Figure 1 This is a logical diagram of the overall process of a channel access method for cross-media communication according to an embodiment of the present invention.

[0047] Figure 2A schematic diagram of data link layer media access control of a channel access method for cross-media communication according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0049] Example 1, with reference to Figure 1 As an embodiment of the present invention, a channel access method for cross-media communication is provided, such as Figure 1 The specific steps shown include:

[0050] S100: Using linear frequency modulation spread spectrum modulation technology at the physical layer, defining a first symbol type by controlling the rise, fall, and sweep times of the linear frequency modulation, and generating a modulated signal; performing a first operation on the modulated signal at the receiving end to determine the starting position of the data packet, and performing a second operation on subsequent symbols to obtain a demodulated symbol state;

[0051] S200: Introducing the request-to-send window mechanism at the data link layer and combining it with the slotted ALOHA protocol to divide communication time slots, achieving efficient channel access and conflict management;

[0052] S300: A forward error correction coding mechanism is used in the transmission control layer to enable the receiving end to correct bit errors or erasure states without retransmission.

[0053] It should be noted that existing cross-media communication technologies are sensitive to signal attenuation and propagation delay at the physical layer. The data link layer struggles to handle uncertain conflicts caused by multipath effects, while the transmission control layer suffers from inefficiency due to high bit error rates and unstable feedback mechanisms. These issues collectively limit the stability and reliability of the communication system. Steps S100 to S300, by introducing an adaptive protocol based on technologies such as linear frequency modulation spread spectrum, effectively enhance the signal's anti-interference capability, particularly maintaining a low bit error rate in cross-media communication. Experimental results demonstrate that CSS offers stronger anti-interference capabilities under low signal-to-noise ratio (SNR) conditions than traditional ASK and FSK modulation techniques, significantly improving communication stability and reliability and ensuring efficient data transmission. Compared to existing cross-media communication technologies, the present invention demonstrates superior communication performance in a variety of media, particularly in freshwater, seawater, and soil, where the communication depth and range surpass those of conventional technologies. This makes the system widely applicable in IoT applications and meets the requirements of sensor networks for long-distance, stable transmission. Furthermore, this invention introduces the CSMA / CA and RTS mechanisms at the data link layer, combined with the slotted ALOHA protocol, to achieve more efficient channel access and conflict management. This improved channel access control method allows multiple nodes to avoid channel conflicts in complex environments, reducing packet loss and improving network throughput and reliability. In multi-node environments, the system's successful transmission rate is significantly improved, ensuring smooth cross-media communication.

[0054] Example 2, reference Figure 2 Based on the previous embodiment, this embodiment provides a specific implementation of a channel access method for cross-media communication to illustrate the technical means used in this method.

[0055] In an optional embodiment, a suitable modulation mode is selected according to the application scenario, including but not limited to linear frequency modulation spread spectrum, adaptive modulation and coding spread spectrum, ASK, FSK, etc.

[0056] In the embodiment of the present application, the specific design of the physical layer is described by taking linear frequency modulation spread spectrum modulation technology (CSS) as an example. Due to its unique characteristics, CSS can achieve a longer communication distance and has anti-interference ability. In CSS modulation, the transmitted signal is extended to a wider bandwidth through a frequency sweep called linear frequency modulation. Up-chirp, down-chirp and their scanning time are used here to describe the characteristics of CSS. Assuming that f1 and f2 are the starting frequency and the ending frequency respectively, the time domain functions of up-chirp and down-chirp can be expressed as:

[0057]

[0058] Among them, 0≤t≤T, is the rate at which the frequency increases (or decreases), and T is the time required to sweep from f1 to f2.

[0059] Specifically, the first symbol type is defined by controlling the rise, fall and scan time of the chirp, including: long up chirp (eg 4ms), short up chirp (eg 1ms) and short down chirp (eg 1ms).

[0060] It should be noted that, unlike the method of long-distance radio by manipulating the initial linear frequency modulation frequency, this embodiment utilizes the characteristics of the piezoelectric mechanical antenna and adopts simple rising and falling linear frequency modulation, thereby reducing the inter-symbol interference caused by frequent frequency mutations, while ensuring the robustness of communication through smooth frequency changes within a single symbol.

[0061] In this embodiment of the present application, the step of obtaining the demodulated symbol state includes:

[0062] operating the input signal using a long up-linear frequency modulation, and determining the starting position of the data packet when a correlation peak exceeds a first threshold;

[0063] Operate the subsequent symbols one by one with the short up-line frequency modulation and the short down-line frequency modulation to obtain the first peak value C up and the second peak C down ;

[0064] If the first peak C up Exceeding the second peak C down , and the first peak C up is greater than the second threshold, the symbol state is bit 1; if the second peak C down Exceeding the first peak C up , and the second peak C down is greater than the second threshold, the symbol state is bit 0;

[0065] If none of the conditions are met, the symbol is erased due to strong interference or noise.

[0066] It should be noted that the setting of the first and second thresholds requires a comprehensive consideration of the noise environment, signal characteristics, and system performance requirements. The first threshold is typically set based on a comparison between the preamble (long chirp) and the noise. By measuring the statistical characteristics of the background noise and multiplying it by a safety factor (e.g., 3 to 5 times the noise standard deviation), this ensures reliable detection of the packet start position even under low signal-to-noise ratios while avoiding false alarms. Alternatively, the first threshold can be set proportionally based on the theoretical correlation peak of the preamble to adapt to different channel conditions.

[0067] It should be noted that the setting of the second threshold focuses more on the demodulation reliability at the symbol level. Generally, the correlation peak distribution of short up / down linear frequency modulation signals in the absence of interference is measured experimentally, and an appropriate ratio is selected as the threshold so that it can distinguish between bit 1 and bit 0 and tolerate certain channel fluctuations. This threshold is usually lower than the first threshold to reflect the correlation gain difference of the short frequency modulation signal.

[0068] In the embodiment of the present application, the first operation step is: at the receiving end, the signal is cross-correlated with a known long chirp, the degree of match between the two is calculated, and a correlation result sequence is generated. By scanning the sequence, it is detected whether the correlation peak exceeds a preset first threshold. If it does, the peak position is determined to be the starting position of the data packet; if it does not exceed the threshold, the search window is continuously slid until a peak that meets the conditions is found, thereby determining the start of the data packet;

[0069] In this embodiment of the present application, the second operation involves processing each subsequent symbol segment after determining the starting position of the data packet. Each symbol segment is cross-correlated with the short upper chirp and the short lower chirp, yielding two peak values. The magnitude of these two peak values ​​is then compared and combined with a second threshold to determine the value.

[0070] In the embodiment of the present application, the cross-medium channel is modeled as a binary erasure channel, and the transmitted bit is received correctly or erased with a first probability;

[0071] Specifically, assuming the sender sends a bit (0 or 1), the receiver either receives the bit correctly or receives a message of "bit not received" (i.e., "erasure") with a certain error probability p, thereby providing support for subsequent error correction coding.

[0072] It should be noted that the first probability is a dynamic variable that is strongly related to the medium environment and modulation parameters. Its technical essence lies in converting complex cross-medium channel problems into quantifiable erasure probabilities through the BEC model, thereby supporting the design of error correction mechanisms such as polarization codes. The specific value can be dynamically determined based on the actual cross-medium channel characteristics.

[0073] It should be noted that step S100 above effectively improves the signal's anti-interference capability and transmission stability in a cross-media environment. At the receiving end, the starting position of the data packet is detected, and the symbols are accurately decoded using correlation operations using short up / down chirp templates, enabling the system to maintain reliable communication quality even under low signal-to-noise ratio conditions. This physical layer solution is specifically optimized for high-attenuation media such as water and soil. It reduces inter-symbol interference through smooth frequency variations, providing a robust basic transmission guarantee for cross-media communications.

[0074] In the embodiment of the present application, the above step S200 introduces a request-to-send window mechanism at the data link layer, and divides the communication time slots in combination with the slotted ALOHA protocol to achieve efficient channel access and conflict management, including:

[0075] Specifically, the nodes in the cross-medium communication system are equipped with dual front-end modules, including an acoustic signal front-end and an electromagnetic wave signal front-end. During cross-medium communication, acoustic wave signals or electromagnetic wave signals are selected for data transmission based on the propagation characteristics of the medium.

[0076] It should be noted that in the proposed cross-media communication system, nodes are usually equipped with dual front-end modules that can support two different types of signal transmission, namely acoustic signals (such as ultrasound) and electromagnetic wave signals (such as medium-frequency electromagnetic waves). The acoustic front-end is suitable for communication in high-latency, high-absorption media (such as water, soil, and biological tissue), while the electromagnetic front-end is mainly used for high-speed communication in low-latency media (such as air). By introducing a dual front-end design, it is possible to flexibly respond to changes in different channel characteristics in a cross-media environment, and select the most suitable signal type for data transmission for media with different propagation speeds and loss characteristics.

[0077] It should be noted that cross-media communications in this setting present significant differences in propagation speeds. For example, acoustic signals propagate much slower than electromagnetic waves through media. This necessitates careful attention to collision detection and media access issues caused by propagation delays during data link layer design. This challenge is particularly acute in high-latency environments such as underwater and soil. Therefore, in protocol design, using ultrasonic and electromagnetic waves as examples, we systematically analyze the adaptation of media access control mechanisms at varying propagation rates and propose a unified, scalable channel access method.

[0078] In traditional data link layer mechanisms, media access control protocols (such as ALOHA and CSMA / CA) are usually used to coordinate the access of multiple nodes to shared wireless channels to reduce conflicts. However, in a medium environment with slow propagation speed, carrier sensing is prone to failure. Figure 2 As shown in Figure (b), when node B begins transmitting, due to propagation delay, node A fails to detect that the channel is occupied within its listening window, misjudging it as idle, leading to a collision. This type of collision caused by propagation delay is difficult to completely resolve even by extending the listening window, and is particularly severe when the time difference between nodes initiating collision detection is less than the propagation delay.

[0079] In the embodiment of the present application, the processing of the data link layer specifically includes:

[0080] The request-to-send window mechanism is introduced. Before transmitting data, a node broadcasts a request-to-send signal. When the surrounding nodes receive the request-to-send signal, they know that the channel will be occupied. Figure 2 (c) This mechanism effectively reduces the incidence of concurrent conflicts;

[0081] Combined with the slotted ALOHA protocol, the communication time is divided into uniform time slots, such as Figure 2 The node shown in (d) only sends a request to send signal at the beginning of a time slot. If it detects a request to send signal sent by other nodes, it will delay for a random number of time slots and try to transmit again to reduce the probability of collision.

[0082] In an optional embodiment, due to the high propagation speed of electromagnetic wave channels, the conventional CSMA / CA mechanism is still applicable, allowing nodes to perceive the channel status in real time and appropriately schedule transmissions. Therefore, based on the different physical channel characteristics, a variety of access strategies such as ALOHA, RTS / CTS, and CSMA / CA are flexibly adopted to ensure efficient and low-contention data transmission in both acoustic wave-dominated media environments and those dominated by electromagnetic wave propagation. This significantly improves the adaptability and overall performance of cross-media communication systems in complex and changing environments.

[0083] It should be noted that step S200 above effectively addresses channel conflicts caused by propagation delays in cross-media communications by introducing a request-to-send window mechanism and combining it with the slotted ALOHA protocol. This mechanism requires nodes to send an RTS signal before transmission and coordinates multi-node access by allocating unified time slots, significantly reducing the probability of conflicts in high-latency media such as acoustic waves. Furthermore, the CSMA / CA mechanism is still used for electromagnetic wave communications, enabling adaptive optimization for different media characteristics, thereby improving the reliability and throughput of the overall communication system.

[0084] In the embodiment of the present application, the above step S300 adopts a forward error correction coding mechanism in the transmission control layer to enable the receiving end to correct bit errors or erasure states without retransmission, including:

[0085] Perform polarization transformation on multiple channels to divide the channels into high-reliability channels and low-reliability channels;

[0086] The transmitter encodes the data with polar codes, maps the information bits to high-reliability channels, and fills fixed frozen bits in low-reliability channels.

[0087] Based on the characteristics of binary erasure channels, a polarization-coded redundant structure is embedded in the transmitted data packets.

[0088] The receiving end recovers the original data with bit erasure or bit errors through the polarization decoding process.

[0089] It should be noted that in cross-media communication environments, even with the introduction of various robustness enhancement mechanisms at the physical and data link layers, data packets may still be damaged by environmental noise, medium discontinuities, or partial channel collisions. To further enhance communication reliability, the Forward Error Correction (FEC) mechanism is introduced at the transmission control layer, enabling the receiver to correct a certain degree of bit errors or erasures without requiring retransmission.

[0090] In an optional embodiment, the adopted forward error correction coding scheme is flexible, and different types of coding methods can be selected according to actual channel conditions, including but not limited to polar codes, low-density parity-check codes, or convolutional codes.

[0091] In the embodiment of the present application, polarization code is used as an example for encoding. Polarization code is a forward error correction coding method designed based on channel polarization theory. It can work close to the Shannon limit in a binary erasure channel environment and is particularly suitable for the cross-media communication channel environment modeled in this embodiment. By performing polarization transformation on multiple independent channels, they are divided into two categories: high reliability and low reliability. During the encoding process, information bits are mapped to high-reliability channels, while low-reliability channels are filled with fixed frozen bits. By embedding the redundant structure of polarization coding in the data packet, even in the presence of bit erasure or bit error, the receiving end can restore the original data through the polarization decoding process, thereby significantly improving the data integrity and system transmission success rate in complex cross-media environments.

[0092] It should be noted that step S300, by employing a forward error correction (FEC) coding mechanism, can significantly improve data transmission reliability in high-erasure, high-bit-error-rate (BER) environments of cross-media communications. The receiving end can directly correct bit errors or erasure states without relying on retransmissions, effectively addressing the inefficiency of traditional ARQ mechanisms caused by unstable feedback paths. Experiments have shown that this solution is particularly suitable for binary erasure channel environments. By leveraging the redundant structure of polar codes and the polarization characteristics of the channel, it can maintain a high data recovery success rate even under dynamically changing media conditions, thereby reducing system latency and improving overall transmission efficiency.

[0093] Embodiment 3: This embodiment provides a channel access system for cross-medium communication, including:

[0094] A linear frequency modulation spread spectrum module is configured to employ linear frequency modulation spread spectrum modulation technology at the physical layer, define a first symbol type by controlling the rise, fall, and sweep times of the linear frequency modulation, and generate a modulated signal; perform a first operation on the modulated signal at the receiving end to determine the starting position of the data packet, and perform a second operation on subsequent symbols to obtain a demodulated symbol state;

[0095] The media access control module is used to introduce a request-to-send window mechanism at the data link layer and divide communication time slots in combination with the slotted ALOHA protocol to achieve efficient channel access and conflict management;

[0096] The polar code encoding module is used to implement the forward error correction coding mechanism in the transmission control layer, so that the receiving end can correct bit errors or erasure states without retransmission.

[0097] It should be noted that the technical solution of the channel access system for cross-media communication and the technical solution of the channel access method for cross-media communication mentioned above belong to the same concept. For the details not described in detail in the technical solution of the channel access system for cross-media communication in this embodiment, please refer to the description of the technical solution of the channel access method for cross-media communication mentioned above.

[0098] The above-mentioned unit modules can be embedded in or independent of the processor in the electronic device in the form of hardware, or can be stored in the memory of the electronic device in the form of software, so that the processor can call and execute the corresponding operations of the above-mentioned modules.

[0099] This embodiment also provides an electronic device, which includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the electronic device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a channel access method for cross-media communication is implemented. The display screen of the electronic device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the electronic device can be a touch layer covering the display screen, or a button, trackball or touchpad provided on the electronic device housing, or an external keyboard, touchpad or mouse.

[0100] This embodiment further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method proposed in the above embodiment is implemented.

[0101] The storage medium proposed in this embodiment and the method proposed in the above embodiment belong to the same inventive concept. For technical details not fully described in this embodiment, please refer to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0102] Through the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented with the help of software and necessary general-purpose hardware, and of course it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for enabling an electronic device (which can be a personal computer, server, or network device, etc.) to execute the method of the embodiment of the present invention.

[0103] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0104] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0105] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A channel access method for cross-medium communication, characterized in that: include: A linear frequency modulation spread spectrum modulation technique is adopted at the physical layer, a first symbol type is defined by controlling the rise, fall and sweep time of the linear frequency modulation, and a modulated signal is generated; Performing a first operation on the modulated signal at the receiving end to determine the starting position of the data packet, and performing a second operation on subsequent symbols to obtain a demodulated symbol state; Introducing the request-to-send window mechanism at the data link layer and combining it with the slotted ALOHA protocol to divide communication time slots, thus achieving efficient channel access and conflict management. A forward error correction coding mechanism is adopted in the transmission control layer to enable the receiving end to correct bit errors or erasure states without the need for retransmission.

2. A channel access method for cross-media communication according to claim 1, characterized in that: The first symbol type includes a long up chirp, a short up chirp, and a short down chirp.

3. A channel access method for cross-media communication according to claim 2, characterized in that: The acquiring of the demodulated symbol state comprises: performing an operation on an input signal using the long up-chirp, and determining a starting position of the data packet when a correlation peak exceeds a first threshold; Calculate the short upper chirp and the short lower chirp one by one on subsequent symbols to obtain a first peak value and a second peak value; If the first peak value exceeds the second peak value and the first peak value is greater than a second threshold, the symbol state is bit 1; if the second peak value exceeds the first peak value and the second peak value is greater than a second threshold, the symbol state is bit 0; If none of the conditions are met, the symbol is erased due to strong interference or noise.

4. A channel access method for cross-media communication according to claim 3, characterized in that: Modeling the cross-medium channel as a binary erasure channel, the transmitted bits are either received correctly or erased with a first probability.

5. A channel access method for cross-media communication according to claim 1, characterized in that: In the cross-media communication system, the node is equipped with dual front-end modules, including an acoustic signal front-end and an electromagnetic wave signal front-end. During cross-media communication, the acoustic signal or electromagnetic wave signal is selected for data transmission according to the propagation characteristics of the medium.

6. A channel access method for cross-media communication according to claim 5, characterized in that: The processing of the data link layer includes: A request-to-send window mechanism is introduced. Before transmitting data, a node broadcasts a request-to-send signal. When surrounding nodes receive the request-to-send signal, they are informed that the channel will be occupied. The communication time is divided into uniform time slots in combination with the slotted ALOHA protocol. A node only sends the request to send signal at the beginning of a time slot. If it detects the request to send signal sent by other nodes, it will try to transmit again after delaying a random number of time slots to reduce the probability of collision.

7. A channel access method for cross-media communication according to claim 1, characterized in that: The processing of the transmission control layer includes: Perform polarization transformation on multiple channels to divide the channels into high-reliability channels and low-reliability channels; The transmitting end performs polar code encoding on the data, maps the information bits to the high-reliability channel, and fills the low-reliability channel with fixed frozen bits; Based on the characteristics of binary erasure channels, a polarization-coded redundant structure is embedded in the transmitted data packets. The receiving end recovers the original data with bit erasure or bit errors through the polarization decoding process.

8. A channel access system for cross-media communication, applying the channel access method for cross-media communication according to any one of claims 1 to 7, characterized in that: include: A linear frequency modulation spread spectrum module is configured to employ linear frequency modulation spread spectrum modulation technology at the physical layer, define a first symbol type by controlling the rise, fall, and sweep times of the linear frequency modulation, and generate a modulated signal; perform a first operation on the modulated signal at the receiving end to determine the starting position of the data packet, and perform a second operation on subsequent symbols to obtain a demodulated symbol state; The media access control module is used to introduce a request-to-send window mechanism at the data link layer and divide communication time slots in combination with the slotted ALOHA protocol to achieve efficient channel access and conflict management; The polar code encoding module is configured to employ a forward error correction coding mechanism in the transmission control layer to enable the receiving end to correct bit errors or erasure states without the need for retransmission.

9. An electronic device comprising a memory and a processor, characterized in that: The memory is used to store computer-executable instructions, and the processor implements the steps of a channel access method for cross-media communication according to any one of claims 1 to 7 when executing the computer-executable instructions.

10. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that: When the computer executable instructions are executed by a processor, the steps of a channel access method for cross-media communication according to any one of claims 1 to 7 are implemented.

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