Wireless signal transmission method and system for borehole television

Abstract

The invention provides a wireless signal transmission method and system for a borehole television, and belongs to the technical field of underground signal transmission. Comprising the following steps that a plurality of drill rods and drill bits are arranged on a drilling machine, the drill rods are sequentially connected, the drill rod located at the head end is fixedly connected with the drill bits, and the drill rod located at the tail end is rotationally connected with the drilling machine; acquiring a hole wall image of a horizontal excavation section in the rock mass, and converting the hole wall image into a data packet; a network transmission relay station is arranged in each drill rod; the different network transmission relay stations are in communication connection with each other until all the data packets arrive at the tail end network transmission relay station, and the tail end network transmission relay station sends the data packets to the host at the drilling machinery; wherein the network transmission relay station at the non-tail end enables the data packet at the current position to selectively skip one or more adjacent network transmission relay stations to realize parallel transmission; and the total delay of the data packet passing through the plurality of network transmission relay stations is minimum.

Description

Technical Field

[0001] This invention relates to the field of underground signal transmission technology, and in particular to a wireless signal transmission method and system for borehole television. Background Technology

[0002] The principle of a borehole television system is to use CCD optical devices in downhole equipment to continuously display borehole wall images in a 360° omnidirectional manner. An image processing system then stitches, records, and saves the acquired borehole wall images, presenting them in 2D or 3D form to create a developed borehole wall diagram or a columnar section. For vertical boreholes, images of the borehole wall are typically obtained by lowering the wired cable under gravity within the already excavated vertical hole. However, this gravity-based method is not suitable for horizontal boreholes, such as those drilled ahead of the tunnel face.

[0003] Therefore, a wireless signal transmission method and system for borehole television is proposed. By setting up a camera device and a data acquisition terminal at the horizontally moving drill bit, the image data at the drill bit is transmitted outward in real time via wireless transmission, which is very necessary to meet the real-time transmission requirements for borehole wall imaging analysis in the horizontal direction. Summary of the Invention

[0004] In view of this, the present invention proposes a wireless signal transmission method and system for borehole television that is suitable for imaging the inner surface of horizontal borehole walls and meets the low latency requirements for data transmission.

[0005] On one hand, the present invention provides a wireless signal transmission method for hole-punch television, comprising the following steps: Several drill rods and drill bits are configured on the drilling machinery. The drill rods are connected in sequence. The drill rod at the first end is fixedly connected to the drill bit, and the drill rod at the last end is rotatably connected to the drilling machinery. Several cameras are circumferentially mounted on the side of the drill bit to acquire borehole wall images of the horizontally excavated sections inside the rock mass; a data acquisition terminal is installed inside the drill bit, which is connected to the several cameras; the data acquisition terminal converts the borehole wall images acquired by each camera into data packets. Several drill pipes are equipped with network transmission relay stations; the data acquisition terminal is connected to the first-end network transmission relay station, and different network transmission relay stations are connected to each other until all data packets reach the last-end network transmission relay station, which then sends the data packets to the host machine at the drilling machinery. Among them, non-terminal network transmission relay stations enable data packets at the current location to selectively skip one or more adjacent network transmission relay stations, achieving parallel transmission; through optimization, the total delay of data packets from the first network transmission relay station to the last network transmission relay station is minimized.

[0006] Based on the above technical solution, preferably, the network transmission relay station has a preset transmission sequence and a waiting sequence. The transmission objects received by the network transmission relay station are sequentially filled into the transmission sequence. When the transmission sequence is full, the transmission objects are moved to the waiting sequence; when the number of transmission objects in the waiting sequence reaches a certain threshold... W current Greater than the set threshold W th At this time, the current network transmission relay station enables parallel transmission, sending the transmission objects in the waiting sequence in parallel, with each transmission object according to a jump step size. k Transmission is carried out across at least one adjacent network transmission relay station.

[0007] Preferably, the transmitted object is a data packet or a data fragment; when the size of the data packet exceeds the ideal fragment size, the current network transmission relay station automatically fragments the data packet into several data fragments; when the size of the data packet does not exceed the ideal fragment size, the data packet does not need to be fragmented.

[0008] Further preferred, waiting for a set threshold W th It is based on the maximum capacity of the transmission sequence. Q max The average time required for each network relay station to process one transmission object T proc Average arrival interval of transmitted objects and safety margin factor l Calculated.

[0009] A further preferred method is to send the transmission objects in the waiting sequence in parallel, with each transmission object sent according to a jump step size. k Transmission across at least one adjacent network relay station is defined as marking each network relay station from the drill bit to the host as... RS i = RS 1. RS 2、…、 RS N , N The number of drill pipes. i ∈ N The transmission objects in the waiting sequence, including several data fragments obtained by fragmenting the same data packet and several data packets that do not need to be fragmented, are subjected to multi-channel parallel transmission and allocated to [various channels]. P For each parallel transmission channel, considering fragmentation time overhead, routing decision delay, necessary delay of effective processing stations, parallel hop delay, and excess queuing delay, construct the total transmission delay. T total The model.

[0010] Furthermore, the number of parallel transmission channels is preferred. P It is based on the received signal strength of the current network transmission relay station. RSSI Length of a single drill pipe section L Channel gain coefficient Length attenuation factor and normalized signal quality Decide.

[0011] Furthermore, the optimization aims to minimize the total delay of data packets from the first network relay station to the last network relay station. This optimization includes: 1) adaptive adjustment of the threshold for the ideal fragment size; and 2) setting the total transmission delay. T total 3) Given channel capacity limit.

[0012] Furthermore, the header of the transmission objects sent in parallel includes the following fields: The transmission object source field A1 is used to record the camera number and reception timestamp corresponding to the transmission object source; The fragmentation flag A2 for the transmitted object is set to 1 if the size of the transmitted object exceeds the ideal fragment size, and fragmentation is required; otherwise, the fragmentation flag A2 in the packet header is set to 0. The total number of fragments for the transmitted object is A3. When the fragmentation flag A2 of the transmitted object is set to 1, the number of fragments required for the transmitted object is determined. Enter the number of shards required. m , S The size of the data packet; The fragment sequence number A4 of the currently transmitted object is filled in based on the total number of fragments A3 of the transmitted object and the sequence number of the current fragment. The value range of the sequence number of the current fragment is 1, 2, 3, ... m ; The current transmission object's planned jump step size A5 is used to record the number of adjacent network transmission relay stations that the current transmission object plans to skip during the next transmission along the drill pipe. The routing information A6 of the network relay stations through which the current transmission object passes is used to sequentially record the route of the current transmission object from the first network relay station. RS 1 The markers of each network transmission relay station actually reached during the process of reaching the current network transmission relay station; The checksum field A7 is used to reserve check information. After the transmitted object arrives at the target network relay station for the next transmission, the reserved check information is verified. If the verification is successful, the target network relay station's mark is added, and the reserved check information is updated.

[0013] A further preferred approach is to reserve verification information based on the subscripts of the markers of each network transmission relay station to which the transmitted object actually arrives, combined with the video content, the feature identifiers of the network transmission relay stations, and the reserved verification code.

[0014] On the other hand, the present invention also provides a wireless signal transmission system for hole-punch television, comprising: The drilling machinery has several drill rods and drill bits mounted on it. The drill rods are connected in sequence, with the first drill rod fixedly connected to the drill bit and the last drill rod rotatably connected to the drilling machinery. The borehole wall image acquisition unit is located at the drill bit and is used to acquire borehole wall images of the horizontally excavated section inside the rock mass and convert the borehole wall images into data packets. Several network transmission relay stations are sequentially set on several drill pipes. Different network transmission relay stations are interconnected. The network transmission relay station at the beginning is also connected to the borehole wall image acquisition unit to acquire data packets. The data packets are transmitted to the end network transmission relay station along the axial extension direction of the drill pipe. The end network transmission relay station sends the data packets to the host at the drilling machinery. The non-end network transmission relay stations selectively skip one or more adjacent network transmission relay stations to achieve parallel transmission of the acquired data packets, thus minimizing the total delay of the data packets passing through several network transmission relay stations.

[0015] The present invention provides a wireless signal transmission method and system for borehole television, which has the following advantages compared with the prior art: (1) This scheme adopts a dual queue structure. When the transmission sequence is full and the waiting sequence exceeds the preset threshold, a certain number of adjacent network transmission relay stations are selectively skipped. When the current network transmission relay station is congested due to the long transmission queue, multi-channel parallel transmission is realized, reducing the overall transmission delay and improving the real-time performance of video data transmission. (2) The ideal fragment size can be adaptively adjusted, thereby reducing invalid or meaningless allocation overhead and helping to shorten the overall delay of the transmitted object; (3) The number of parallel channels takes into account the influence of received signal strength and the length of a single drill pipe, and selectively adopts single-channel or multi-channel parallel transmission; (4) The header of the transmitted object is set with a complete transmission path trace and an update mechanism based on the path trace and video content hash value to build an anti-tampering verification chain. Moreover, the transmission path is traceable and the fault trajectory can be accurately located and investigated, thus improving the operation and maintenance efficiency. Attached Figure Description

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

[0017] Figure 1 This is a flowchart illustrating the steps of a wireless signal transmission method and system for borehole television according to the present invention. Figure 2 This is a hardware schematic diagram of a wireless signal transmission method and system for borehole television according to the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] For horizontally oriented holes, such as boreholes drilled ahead of the tunnel face, the conventional gravity-based lowering method is not applicable. For example... Figure 1 As shown, in one aspect, the present invention provides a wireless signal transmission method for hole-punch television, comprising the following steps: S1: Several drill rods and drill bits are configured on the drilling machinery. The drill rods are connected in sequence. The drill rod at the first end is fixedly connected to the drill bit, and the drill rod at the last end is rotatably connected to the drilling machinery. S2: Several cameras are circumferentially arranged on the side of the drill bit to acquire borehole wall images of the horizontal excavation section inside the rock mass; a data acquisition terminal is installed inside the drill bit, and the data acquisition terminal is connected to several cameras; the data acquisition terminal converts the borehole wall images acquired by each camera into data packets. S3: Several drill pipes are equipped with network transmission relay stations; the data acquisition terminal is connected to the first-end network transmission relay station, and different network transmission relay stations are connected to each other until all data packets reach the last-end network transmission relay station, which then sends the data packets to the host machine at the drilling machinery; the data packets are transmitted axially through multiple network transmission relay stations. Among them, non-terminal network transmission relay stations allow data packets at the current location to selectively skip one or more adjacent network transmission relay stations, enabling parallel transmission; through optimization, the total delay of data packets from the first network transmission relay station to the last network transmission relay station is minimized, so as to meet the reliable transmission of high-speed, high-definition burst data.

[0020] The reason for implementing parallel transmission of objects is that the processing capacity of network relay stations is limited. If chained sequential transmission were used, the processing and waiting times would be very long. In this embodiment, a transmission sequence and a waiting sequence are preset within the network relay station. Transmission objects received by the current network relay station are sequentially filled into the transmission sequence. When the transmission sequence is full, the transmission objects are moved to the waiting sequence; when the number of transmission objects in the waiting sequence reaches a certain threshold... W current Greater than the set threshold W th At this time, the current network transmission relay station enables parallel transmission, sending the transmission objects in the waiting sequence in parallel, with each transmission object according to a jump step size. k Transmission is carried out across at least one adjacent network transmission relay station.

[0021] Based on the order in which they arrive at the network relay station, transmission objects that can be processed quickly enter the transmission sequence directly. When the transmission sequence is full, subsequent transmission objects arriving at the current network relay station enter the waiting sequence and are ordered according to their arrival time. If the waiting sequence is too long, it will require a significant amount of waiting time; therefore, a waiting threshold is set. W th Assess whether the length of the docking is tolerable, once the number of objects to be transmitted in the waiting sequence is reached. W currentt Greater than the set threshold W th If the target network is not waiting for processing by the currently queued network relay station, the transmission target will immediately be activated. Instead, it will skip one or more adjacent network relay stations, reach the target network relay station, and bypass the nearest network relay station to avoid localized long-term network congestion.

[0022] In this embodiment, the transmission object is a data packet that does not need to be fragmented or a data fragment obtained after data packet fragmentation; the size of the data packet... S Exceeding the ideal fragment size S th At this time, the current network transmission relay station automatically fragments the data packet into several data fragments; the size of the data packet... S No more than the ideal fragment size S th At this time, data packets do not need to be fragmented.

[0023] In this embodiment, the waiting time is set to a threshold. W th It is based on the maximum capacity of the transmission sequence. Q max The average time required for each network relay station to process one transmission object T proc Average arrival interval of transmitted objects and safety margin factor l The calculation results are as follows: The maximum capacity of transport sequences in a molecule. Q max The average time required for each network relay station to process one transmission object T proc The product of these two values ​​represents the time required to clear the transmission sequence, divided by the average arrival interval of the transmitted objects in the denominator. The obtained data represents the number of new transmission objects arriving at the current network relay station when the transmission sequence is cleared, by appropriately specifying a security margin factor. l It is generally recommended to wait until a threshold is set. W th This is more than twice the number of new transmission objects arriving at the current network transmission relay station when the transmission sequence is cleared.

[0024] Based on the foregoing, when the number of transmission objects in the waiting sequence... W current Greater than the set threshold W th At that time, the transmission objects in the waiting sequence are sent in parallel, with each transmission object according to the jump step size. k Transmission across at least one adjacent network relay station is defined as marking each network relay station from the drill bit to the host as... RS 1. RS 2、…、 RS N , N The number of drill pipes; the transmission objects in the waiting sequence, including several data fragments obtained by fragmenting the same data packet and several data packets that do not need to be fragmented, are performed on multi-channel parallel transmission and allocated toP For each parallel transmission channel, considering the time overhead of data fragmentation, routing decision delay, necessary delay of effective processing stations, parallel hop delay, and excess queuing delay, a total transmission delay model is constructed: ,in, For packet fragmentation identification; This is the time overhead for packet fragmentation; Delay for routing decisions; For floor operations, T t Transmission delay per unit distance D This refers to the standard spacing of the drill pipe. As a necessary delay for an effective processing station; For the data slice transmission delay, For the transmission delay of data packets that do not need to be fragmented; To extend the waiting time for those exceeding the quota, This refers to the average waiting time for data fragments or data packets that do not need to be fragmented when the transmission sequence is full.

[0025] For a single transmitted object, the total transmission delay is... T total In the model, the first term on the right side of the equals sign is the dedicated overhead of fragmentation. For data packets that do not need to be fragmented, the transmission delay does not include this term. The second term on the right side of the equals sign is the routing decision delay, which is used to determine the optimal hop step size, that is, the optimal result under the premise of minimizing the impact of signal attenuation of the transmitted object or the drill pipe distance on the transmission process. Molecular N -1 corresponds to N The denominator represents the number of equidistant signal transmission intervals between network transmission relay stations on the drill pipe. k The step size for each jump corresponds to one or more intervals. The third term on the right side of the equation represents the overall delay of the effective processing station, i.e., the data processing delay of the network transmission relay station that actually participates in the relay transmission of the transmitted object. The fourth term on the right side of the equation represents the parallel transmission delay, which is the delay after the fragmented data is fragmented into... P Data is transmitted through multiple parallel transmission channels, and the transmission delay of data slices is... Essentially, it involves multiple data slices moving along... P The transmission delay of parallel transmission channels in the drill pipe axial direction, and the transmission delay of data packets that do not need to be fragmented. Essentially, it represents the transmission delay of data packets that do not need to be fragmented along the drill pipe axis. For each parallel transmission channel, the number of adjacent network relay stations it traverses may not be exactly equal; the fifth term on the right side of the equation represents the queuing delay of the waiting sequence. The essence is the idle waiting time in the waiting sequence, that is, waiting to enter. PThe waiting time of each parallel transmission channel. The total transmission delay of all transmitted objects is calculated. T total This gives the total delay of data transmission for the current drilling task.

[0026] In this embodiment, the number of parallel transmission channels P It is based on the received signal strength of the current network transmission relay station. RSSI Length of a single drill pipe section L Channel gain coefficient Length attenuation factor and normalized signal quality Decide: ,in This represents the received signal strength of the current network transmission relay station. The lower and upper limits of the received signal strength; normalized signal quality. , ; The upper limit of the parallel transmission channel; the jump step size. k Parallel transmission channel P The quantities satisfy the following relationship: ,in Total bandwidth For the bandwidth of a single transmission channel, the jump step size k It is a positive integer. It can be set. These are -85dBm and -60dBm, respectively. Channel gain coefficient. and The total bandwidth is proportional to the channel gain coefficient. In this embodiment, the channel gain coefficient is given. The value range is [3, 5], and the length attenuation factor is... The given value is 0.05 / m. The meaning of the above conditional formula is: Located in a weak signal region. At that time, the number of parallel transmission channels is forced. P The value is 1, and single-channel transmission is used; in the signal transition region At that time, the received signal strength and the number of parallel transmission channels P The number of parallel transmission channels is directly proportional to the number of parallel transmission channels. P With the length of a single drill pipe L The length is inversely proportional; in the strong signal region At that time, the maximum number of parallel transmission channels is used. .

[0027] Step S3 describes optimizing the process to minimize the total delay of data packets from the first network relay station to the last network relay station. The optimization process includes the following: 1) Adaptive adjustment of the threshold for the ideal fragment size: given a threshold for the ideal allocation size ,in This is the bandwidth utilization factor. For the bandwidth of a single transmission channel, For video frame period, The signal-to-noise ratio (SNR) is related to the received signal strength. Proportional; The calculation is performed to take the maximum value. The purpose of this constraint is to increase the threshold of the ideal allocation size and reduce the number of fragments when the bandwidth of a single transmission channel is high, and to decrease the threshold of the ideal allocation size and increase the number of fragments when the signal-to-noise ratio is low. Usually, once the number of fragments is determined, the fragmented data fragments are not further fragmented. The denominator in the formula represents the theoretical transmission capacity per unit bandwidth.

[0028] 2) Maximum allowed end-to-end latency: , This is the safety margin factor.

[0029] 3) Channel capacity limitations: ,in The maximum hardware transmission capacity is determined by the following: for example, the data processing capability of a DSP chip is 200Mbps and the bus bandwidth is 300Mbps. The lower limit of the data processing capability in the transmission link is selected as the maximum hardware transmission capacity. As an efficiency loss factor, considering the efficiency loss caused by failed retransmissions and data verification, the given efficiency loss factor is 0.15-0.25.

[0030] To verify the reliability of transmitted objects, the header of each transmitted object sent in parallel includes the following fields: The transmission object source field A1 is used to record the camera number and reception timestamp corresponding to the transmission object source; The fragmentation flag A2 for the transmitted object is set to 1 if the size of the transmitted object exceeds the ideal fragment size, and fragmentation is required; otherwise, the fragmentation flag A2 in the packet header is set to 0. The total number of fragments for the transmitted object is A3. When the fragmentation flag A2 of the transmitted object is set to 1, the number of fragments required for the transmitted object is determined. Enter the number of shards required. m , S The size of the data packet; The fragment sequence number A4 of the currently transmitted object is filled in based on the total number of fragments A3 of the transmitted object and the sequence number of the current fragment. The value range of the sequence number of the current fragment is 1, 2, 3, ... m ; The current transmission object's planned jump step size A5 is used to record the number of adjacent network transmission relay stations that the current transmission object plans to skip during the next transmission along the drill pipe. The routing information A6 of the network relay stations through which the current transmission object passes is used to sequentially record the route of the current transmission object from the first network relay station. RS 1 The markers of each network transmission relay station actually reached during the process of reaching the current network transmission relay station; The checksum field A7 is used to reserve check information. After the transmitted object arrives at the target network relay station for the next transmission, the reserved check information is verified. If the verification is successful, the target network relay station's mark is added, and the reserved check information is updated.

[0031] The reserved verification information in the verification code field A7 is generated based on the subscripts of the markers of each network transmission relay station that the transmitted object actually arrives at, combined with the video content, the feature identifiers of the network transmission relay stations, and the reserved verification code; let the subscript sequence of the markers of each network transmission relay station that the transmitted object actually arrives at be... path n =[1, ..., i -1, i , i +1, ..., n The initial value of the reserved verification information is... , key To reserve a verification code, The characteristic identifier of the first network transmission relay station to which the transmitted object actually arrives; for the first i The actual network transmission relay station that arrives, with reserved verification information as follows: ,in The actual arrival time of the transmitted object i The characteristic identifier of a network transmission relay station The actual arrival time of the transmitted object i The reserved verification information of the network transmission relay station, the actual arrival time of the transmitted object. i Path sequence of a network transmission relay station path i =[1, ..., i -1, i ], M The || operator is used to concatenate bytes to transfer the content of the object. For hash functions; the actual number of times the transmitted object arrives. i+ One network relay station verifies the reserved verification information. Upon successful verification, the updated reserved verification information is obtained as follows: ,in The actual arrival time of the transmitted object i+1 characteristic identifier for network transmission relay stations, The actual arrival time of the transmitted object i Path sequence of +1 network relay station path i =[1, ..., i -1, i , i +1].

[0032] When the i After successful verification by +1 network transmission relay station, proceed to the next transmission step; if the first... i If the verification of +1 network transmission relay station fails, then the first... i +1 network relay station will send to the first i -1 network transmission relay station and the first i The network transmission relay station obtains again PCC i and PCC i-1 The reserved verification information is retrieved again for verification. If the verification passes, the reserved verification information is updated and the next transmission is performed; otherwise, the next transmission is performed. i If +1 network transmission relay station fails verification three times consecutively, then for the... i The network transmission relay station to the first i Adjust the path of +1 network transmission relay station, try to still use the current parallel transmission channel but reduce the number of network transmission relay stations crossed, or replace it with a parallel transmission channel with better received signal strength.

[0033] To avoid data loss due to accidents, for the same parallel transmission channel, a certain proportion of already sent transmission objects can be retransmitted. For example, the network relay station corresponding to the current parallel transmission channel can clear four transmission objects from its buffer after sending every five or more transmission objects, retaining only one as redundant data. Before sending the sixth transmission object, the redundant data is sent, and the header and content of the redundant data are exactly the same as one of the already sent transmission objects. This redundant transmission method greatly reduces the likelihood of retransmitted data needing to pass through all network relay stations without significantly increasing communication overhead.

[0034] On the other hand, the present invention also provides a wireless signal transmission system for borehole television, for implementing the above method, comprising: The drilling machinery has several drill rods and drill bits mounted on it. The drill rods are connected in sequence, with the first drill rod fixedly connected to the drill bit and the last drill rod rotatably connected to the drilling machinery. The borehole wall image acquisition unit is located at the drill bit and is used to acquire borehole wall images of the horizontally excavated section inside the rock mass and convert the borehole wall images into data packets. Several network transmission relay stations are sequentially set on several drill pipes. Different network transmission relay stations are interconnected. The network transmission relay station at the beginning is also connected to the borehole wall image acquisition unit to acquire data packets. The data packets are transmitted to the end network transmission relay station along the axial extension direction of the drill pipe. The end network transmission relay station sends the data packets to the host at the drilling machinery. The non-end network transmission relay stations selectively skip one or more adjacent network transmission relay stations to achieve parallel transmission of the acquired data packets, thus minimizing the total delay of the data packets passing through several network transmission relay stations.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 wireless signal transmission method for borehole television, characterized in that, Includes the following steps: Several drill rods and drill bits are configured on the drilling machinery. The drill rods are connected in sequence. The drill rod at the first end is fixedly connected to the drill bit, and the drill rod at the last end is rotatably connected to the drilling machinery. Several cameras are circumferentially mounted on the side of the drill bit to acquire borehole wall images of the horizontally excavated sections inside the rock mass; a data acquisition terminal is installed inside the drill bit, which is connected to the several cameras; the data acquisition terminal converts the borehole wall images acquired by each camera into data packets. Several drill pipes are equipped with network transmission relay stations; the data acquisition terminal is connected to the first-end network transmission relay station, and different network transmission relay stations are connected to each other until all data packets reach the last-end network transmission relay station, which then sends the data packets to the host machine at the drilling machinery. Among them, non-terminal network transmission relay stations enable data packets at the current location to selectively skip one or more adjacent network transmission relay stations, achieving parallel transmission; through optimization, the total delay of data packets from the first network transmission relay station to the last network transmission relay station is minimized.

2. The wireless signal transmission method for borehole television according to claim 1, characterized in that, The network transmission relay station has a preset transmission sequence and a waiting sequence. The transmission objects received by the network transmission relay station are filled into the transmission sequence in sequence. When the transmission sequence is full, the transmission objects are moved into the waiting sequence. When the number of transmission objects in the waiting sequence W current Greater than the set threshold W th At this time, the current network transmission relay station enables parallel transmission, sending the transmission objects in the waiting sequence in parallel, with each transmission object according to a jump step size. k Transmission is carried out across at least one adjacent network transmission relay station.

3. The wireless signal transmission method for borehole television according to claim 2, characterized in that, The transmitted object is a data packet or a data fragment; when the size of the data packet exceeds the ideal fragment size, the current network transmission relay station automatically fragments the data packet into several data fragments; when the size of the data packet does not exceed the ideal fragment size, the data packet does not need to be fragmented.

4. The wireless signal transmission method for borehole television according to claim 3, characterized in that, Waiting to set threshold W th It is based on the maximum capacity of the transmission sequence. Q max The average time required for each network relay station to process one transmission object T proc Average arrival interval of transmitted objects and safety margin factor l Calculated.

5. The wireless signal transmission method for borehole television according to claim 3, characterized in that, The objects in the waiting sequence are sent in parallel, with each object sent according to a jump step size. k Transmission across at least one adjacent network relay station is defined as marking each network relay station from the drill bit to the host as... RS i = RS 1. RS 2、…、 RS N , N The number of drill pipes. i ∈ N ; The transmission objects in the waiting sequence, including several data fragments obtained by fragmenting the same data packet and several data packets that do not need to be fragmented, are subjected to multi-channel parallel transmission and allocated to [various channels / processes]. P For each parallel transmission channel, considering fragmentation time overhead, routing decision delay, necessary delay of effective processing stations, parallel hop delay, and excess queuing delay, construct the total transmission delay. T total The model.

6. The wireless signal transmission method for borehole television according to claim 5, characterized in that, Number of parallel transmission channels P It is based on the received signal strength of the current network transmission relay station. RSSI Length of a single drill pipe section L Channel gain coefficient Length attenuation factor and normalized signal quality Decide.

7. The wireless signal transmission method for borehole television according to claim 5, characterized in that, The optimization aims to minimize the total delay of data packets from the first network relay station to the last network relay station. The optimization includes the following: 1) Adaptive adjustment of the threshold for the ideal fragment size; 2) Set the total transmission delay T total 3) Given channel capacity limit.

8. The wireless signal transmission method for borehole television according to claim 7, characterized in that, The header of the transmission objects sent in parallel includes the following fields: The transmission object source field A1 is used to record the camera number and reception timestamp corresponding to the transmission object source; If the size of the transmitted object exceeds the ideal fragment size, fragmentation is required, and the transmitted object fragmentation flag A2 in the packet header is set to 1. If the size of the transmitted object does not exceed the ideal fragment size, fragmentation is not required, and the fragmentation flag A2 of the transmitted object in the packet header is set to 0; The total number of fragments for the transmitted object is A3. When the fragmentation flag A2 of the transmitted object is set to 1, the number of fragments required for the transmitted object is determined. Enter the number of shards required. m , S The size of the data packet; The fragment sequence number A4 of the currently transmitted object is filled in based on the total number of fragments A3 of the transmitted object and the sequence number of the current fragment. The value range of the sequence number of the current fragment is 1, 2, 3, ... m ; The current transmission object's planned jump step size A5 is used to record the number of adjacent network transmission relay stations that the current transmission object plans to skip during the next transmission along the drill pipe. The routing information A6 of the network relay stations through which the current transmission object passes is used to sequentially record the route of the current transmission object from the first network relay station. RS 1 The markers of each network transmission relay station actually reached during the process of reaching the current network transmission relay station; The checksum field A7 is used to reserve check information. After the transmitted object arrives at the target network relay station for the next transmission, the reserved check information is verified. If the verification is successful, the target network relay station's mark is added, and the reserved check information is updated.

9. A wireless signal transmission method for borehole television according to claim 8, characterized in that, The reserved verification information is generated based on the subscript of the marker of each network transmission relay station to which the transmitted object actually arrives, combined with the video content, the feature identifier of the network transmission relay station, and the reserved verification code.

10. A wireless signal transmission system for borehole television, used to implement the wireless signal transmission method for borehole television according to any one of claims 1-9, characterized in that, include: The drilling machinery has several drill rods and drill bits mounted on it. The drill rods are connected in sequence, with the first drill rod fixedly connected to the drill bit and the last drill rod rotatably connected to the drilling machinery. The borehole wall image acquisition unit is located at the drill bit and is used to acquire borehole wall images of the horizontally excavated section inside the rock mass and convert the borehole wall images into data packets. Several network transmission relay stations are sequentially set on several drill pipes. Different network transmission relay stations are interconnected. The network transmission relay station at the beginning is also connected to the borehole wall image acquisition unit to acquire data packets. The data packets are transmitted to the end network transmission relay station along the axial extension direction of the drill pipe. The end network transmission relay station sends the data packets to the host at the drilling machinery. The non-end network transmission relay stations selectively skip one or more adjacent network transmission relay stations to achieve parallel transmission of the acquired data packets, thus minimizing the total delay of the data packets passing through several network transmission relay stations.

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