Video transmission method and system

Abstract

The invention relates to the field of video transmission, in particular to a video transmission method and system, and the method comprises the steps: adjusting mobile equipment in a preset range into a phased frequency band cross space connection structure, so as to reduce the mutual interference between the mobile equipment in each stage; the mobile device in the middle stage is used as a relay device, and the number of receiving links and the number of sending links are distributed according to the ratio of the receiving total code rate to the sending total code rate of the mobile device in the stage so as to achieve optimization of the transmission efficiency between the relay device and the center device; meanwhile, the width of the connection links is adjusted according to the number of the connection links of the mobile equipment, and the space connection structure of the mobile equipment is readjusted according to the relation between the transmission rate of the mobile equipment and the video stream code rate.

Description

Technical Field

[0001] The present invention relates to the field of video transmission, and in particular to a video transmission method and system. Background Art

[0002] With the development and popularization of mobile smart devices and mobile communication technologies, mobile terminal direct communication D2D and V2V technologies are widely regarded as one of the key technologies in the next generation of communication systems, especially in the fields of Internet of Vehicles and Internet of Things. Due to the mobile nature of the equipment, wireless transmission should be given priority; although the power and stability of the current vehicle-mounted and object-mounted wireless transmission modules have been greatly improved, the short distance of the direct link is always avoided, so it is considered to connect these wireless transmission modules to each other through relay forwarding and amplification. Although there is currently also video transmission through broadcasting, due to the large video resources, there are also problems such as large frequency band occupancy, large resource consumption and poor video quality, so it is still considered to establish a point-to-point transmission method. The present invention adjusts the spatial layout structure of mobile devices into a frequency band cross structure through a preset method to reduce mutual interference between relay devices at each stage; and allocates the number of receiving links and the number of sending links according to the ratio of the total receiving code rate to the total sending code rate of the relay devices at each stage to optimize the transmission efficiency between the relay devices and the main device; and adjusts the communication channel width of the connection link according to the number of connection links of the relay devices; and calculates the relationship between the transmission rate and the video stream code rate to readjust the connection layout mode of the relay devices. Summary of the invention

[0003] (1) Technical issues to be solved

[0004] The purpose of the present invention is to provide a video transmission method and system to solve the current video acquisition and sharing problems of mobile devices such as Internet of Vehicles and Internet of Things.

[0005] (2) Technical solution

[0006] To achieve the above object, the present invention provides a video transmission method, the method comprising:

[0007] S1. The multi-path wireless connection function of the mobile device is turned on and allows access and access, so that the mobile device can wirelessly connect to multiple other devices or be connected by multiple other devices, and the receiving links and transmitting links of the mobile device are not less than the preset number respectively;

[0008] S2. Mobile devices preferentially connect to other devices that are closer to each other. The central device obtains the mutual connection status and connection distance between the mobile devices to obtain the spatial layout structure between the mobile devices and adjusts the spatial layout structure to a phased frequency band cross structure through a preset method.

[0009] S3, dividing the wireless transmission frequency band into three sub-bands, fixing the wireless transmission frequency band of the mobile device in the same stage to any one of the above three sub-bands, and making the transmission frequency bands of the mobile devices in adjacent stages different from each other; when the stage mobile device receives the video stream signal, adjusting the received signal to the transmission frequency within the allocated frequency band and forwarding and amplifying it;

[0010] S4. Allocate the link quantity and link width of mobile devices at different stages according to a preset channel allocation method, and automatically stagger the channel frequencies of mobile devices at the same stage in space according to a wireless transmission protocol;

[0011] S5. When the central device receives video stream signals from other mobile devices or sends video stream signals to other mobile devices through the above method, it detects the total bit rate and total transmission rate of the video stream transmitted by the mobile devices in each stage according to the preset time interval, and readjusts the spatial layout structure of the mobile devices in each stage according to the relationship between the total bit rate and the total transmission rate.

[0012] Furthermore, the method further includes: the layout of the phased frequency band cross structure is as follows: assuming that the maximum connection distance between mobile devices is M, and the distance between mobile devices in adjacent stages is d ij , where i is different stages, j is different equipment in the same stage, and d ij ≤M; the mobile devices at different stages are adjusted according to the distribution situation and present as irregular surrounding bands centered on the central device; the one closest to the central device is the first stage, and the frequency band of stage i is r i , then the frequency band allocation method is: i =mod(i,3).

[0013] Further, the method also includes: the way of allocating the link quantity and link width of mobile devices at different stages according to the preset channel allocation method is: obtaining the total bit rate of video stream data received by the mobile device at the stage and the total bit rate of video stream data sent by the mobile device at the stage, calculating the average number of receiving links and the average number of sending links according to the ratio between the total receiving bit rate and the total sending bit rate as the number of receiving links and the number of sending links of the mobile device at the stage respectively, and allocating the connection link width according to the number of connection links, and the calculation formula of the average number of receiving links of the mobile device at the stage is:

[0014]

[0015] The formula for calculating the average number of transmission links is:

[0016]

[0017] Where T ij is the number of receiving links of the mobile device in the stage, Sij is the number of sending links, TV ij is the receiving transmission rate, SV ij is the sending transmission rate, is the average number of receiving links of the mobile device in the stage, is the average number of sending links, is the average receiving transmission rate, is the average transmission rate, P ij is the total power of data transmission by the mobile device in the stage and P ij =∑ j (S ij ×SV ij )+∑ j (T ij ×TV ij ); The sum of the number of receiving links and the number of sending links is less than or equal to the upper threshold A of the number of other devices that the mobile device can effectively connect to, that is, T ij +S ij ≤A.

[0018] Furthermore, the method further includes: the manner of allocating the connection link width according to the number of connection links is: the channel width in the current wireless communication standard protocol is fixed, and the mobile device bundles multiple adjacent or non-adjacent channels together through channel bundling to adjust the link width and increase the bandwidth and video stream transmission rate; according to the connection link width W ij The calculation formula for the width of the connection link, which is in inverse proportion to the number of connection links n, is:

[0019] W ij =F(n)=ω1×e ―α·n +b1;

[0020] Among them, ω1 is a coefficient obtained by the maximum likelihood estimation method, α is a constant obtained by the maximum likelihood estimation method, b1 is a bias obtained by the maximum likelihood estimation method, and the independent variable link number n is the average number of receiving links or the average number of sending links obtained by the above method, that is, or And the total link width of the mobile devices in the same stage is also within the frequency band width allocated in that stage, that is, ∑ j W ij ∈r i .

[0021] Furthermore, the method further comprises: the way of re-adjusting the spatial layout structure according to the relationship between the total bit rate and the total transmission rate is: obtaining the distance d between the mobile devices in the adjacent stages ij , the bit rate of the video stream transmitted by the mobile device is B ij, according to the positive proportional relationship between link transmission rate and link width and the need to exclude link isolation width, the link transmission rate function is constructed as:

[0022]

[0023] Where ω2 is the coefficient obtained by maximum likelihood estimation, R ij is the signal-to-noise ratio of the link, f is the average frequency of the link signal, and substituting into the link width formula yields:

[0024]

[0025] When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is greater than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is shortened according to a preset ratio. When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is less than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is increased according to a preset ratio. The calculation method is:

[0026]

[0027] in is the average distance between mobile devices in adjacent stages after replanning, is the average distance between mobile devices in adjacent stages before replanning, ω3 is the preset safety proportional coefficient and ω3<1.

[0028] Based on the same inventive concept, on the other hand, the present invention further provides a video transmission system, the system comprising a wireless connection module, a connection adjustment module, a signal forwarding module, a channel sub-allocation module 1, a channel sub-allocation module 2 and a transmission detection module; the wireless connection module is connected to the connection adjustment module, the signal forwarding module is connected to the transmission detection module, and the channel sub-allocation module 1 is connected to the channel sub-allocation module 2;

[0029] A wireless connection module, wherein the multi-path wireless connection function of the mobile device is turned on and allows access and access, so that the mobile device can wirelessly connect to multiple other devices or be connected by multiple other devices, and the receiving links and transmitting links of the mobile device are not less than a preset number respectively;

[0030] A connection adjustment module is used for mobile devices to preferentially connect to other devices that are closer. The central device obtains the mutual connection status and connection distance between the mobile devices to obtain the spatial layout structure between the mobile devices and adjusts the spatial layout structure to a phased frequency band cross structure through a preset method.

[0031] The signal forwarding module is used to divide the wireless transmission frequency band into three sub-bands, fix the wireless transmission frequency band of the mobile device in the same stage to any one of the above three sub-bands, and the transmission frequency bands of the mobile devices in adjacent stages are different from each other; when the stage mobile device receives the video stream signal, the received signal is adjusted to the transmission frequency within the allocated frequency band and forwarded and amplified;

[0032] The channel sub-allocation modules 1 and 2 are used to allocate the link quantity and link width of mobile devices at different stages according to a preset channel allocation method, and the channel frequencies of mobile devices at the same stage are automatically staggered in space according to the wireless transmission protocol;

[0033] The transmission detection module is used to detect the total bit rate and total transmission rate of the video stream transmitted by the mobile devices in each stage according to the preset time interval when the central device receives the video stream signal of other mobile devices or sends the video stream signal to other mobile devices through the above method, and readjust the spatial layout structure of the mobile devices in each stage according to the relationship between the total bit rate and the total transmission rate.

[0034] Furthermore, the system further comprises: a connection adjustment module, which is used for the layout of the phased frequency band cross structure: assuming that the maximum connection distance between mobile devices is M, and the distance between mobile devices in adjacent stages is d ij , where i is different stages, j is different equipment in the same stage, and d ij ≤M; the mobile devices at different stages are adjusted according to the distribution situation and present as irregular surrounding bands centered on the central device; the one closest to the central device is the first stage, and the frequency band of stage i is r i , then the frequency band allocation method is: i =mod(i,3).

[0035] Furthermore, the system further includes: a channel allocation submodule 1, which is used to allocate the link quantity and link width of mobile devices at different stages according to a preset channel allocation method in the following manner: the total bit rate of video stream data received by the mobile device at the stage and the total bit rate of video stream data sent by the mobile device at the stage are obtained, and the average number of receiving links and the average number of sending links are calculated according to the ratio between the total receiving bit rate and the total sending bit rate as the number of receiving links and the number of sending links of the mobile device at the stage respectively, and the connection link width is allocated according to the number of connection links. The calculation formula for the average number of receiving links of the mobile device at the stage is:

[0036]

[0037] The formula for calculating the average number of transmission links is:

[0038]

[0039] Where T ij is the number of receiving links of the mobile device in the stage, S ij is the number of sending links, TV ij is the receiving transmission rate, SV ij is the sending transmission rate, is the average number of receiving links of the mobile device in the stage, is the average number of sending links, is the average receiving transmission rate, is the average transmission rate, P ij is the total power of data transmission by the mobile device in the stage and P ij =∑ j (S ij ×SV ij )+∑ j (T ij ×TV ij ); The sum of the number of receiving links and the number of sending links is less than or equal to the upper threshold A of the number of other devices that the mobile device can effectively connect to, that is, T ij +S ij ≤A.

[0040] Furthermore, the system further comprises: a channel allocation submodule 2, which is used to allocate the connection link width according to the number of connection links in the following manner: the channel width is fixed in the current wireless communication standard protocol, and the mobile device bundles multiple adjacent or non-adjacent channels together through channel bundling to adjust the link width and increase the bandwidth and video stream transmission rate; according to the connection link width W ij The calculation formula for the width of the connection link, which is in inverse proportion to the number of connection links n, is:

[0041] W ij =F(n)=ω1×e ―α·n +b1;

[0042] Among them, ω1 is a coefficient obtained by the maximum likelihood estimation method, α is a constant obtained by the maximum likelihood estimation method, b1 is a bias obtained by the maximum likelihood estimation method, and the independent variable link number n is the average number of receiving links or the average number of sending links obtained by the above method, that is, or And the total link width of the mobile devices in the same stage is also within the frequency band width allocated in that stage, that is, ∑ j W ij ∈r i .

[0043] Furthermore, the system further comprises: a transmission detection module, which is used to readjust the spatial layout structure according to the relationship between the total bit rate and the total transmission rate by obtaining the distance d between the mobile devices in the adjacent stages. ij, the bit rate of the video stream transmitted by the mobile device is B ij , according to the positive proportional relationship between link transmission rate and link width and the need to exclude link isolation width, the link transmission rate function is constructed as:

[0044]

[0045] Where ω2 is the coefficient obtained by maximum likelihood estimation, R ij is the signal-to-noise ratio of the link, f is the average frequency of the link signal, and substituting into the link width formula yields:

[0046]

[0047] When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is greater than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is shortened according to a preset ratio. When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is less than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is increased according to a preset ratio. The calculation method is:

[0048]

[0049] in is the average distance between mobile devices in adjacent stages after replanning, is the average distance between mobile devices in adjacent stages before replanning, ω3 is the preset safety proportional coefficient and ω3<1.

[0050] (3) Beneficial effects

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] By adjusting multiple mobile devices to a phased frequency band cross-space connection structure, the video stream transmission frequency bands in different phases do not interfere with each other;

[0053] By using the mobile devices in the middle as relay devices to forward and amplify the received signals, the coverage of the entire connection network and the number of device connections can be expanded;

[0054] The number of connection links of the mobile device in the stage is calculated by calculating the total bit rate of the video stream data received by the mobile device in the stage and the total bit rate of the video stream data sent by the mobile device in the stage;

[0055] Dynamically allocate the link width of the connection by obtaining the number of links connected to the mobile device and the link width constraint, and calculate the link transmission rate according to the link width, link signal-to-noise ratio, average frequency of link signals, and interval distance;

[0056] By calculating and determining the total transmission rate of mobile devices and the total bit rate of transmitted video streams at each stage, the average value of the staged preset distance is replanned to give priority to video stream transmission of short-distance mobile devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a flow chart of a video transmission method according to Embodiment 1 of the present invention;

[0058] Figure 2 The figure is a schematic diagram of the composition of a video transmission system according to the first embodiment of the present invention. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] Before giving examples, it is necessary to explain the application scenarios of the present invention. The present invention is aimed at the current mobile terminal direct communication D2D, V2V and other technologies. Because the equipment has the characteristics of mobility, wireless transmission should be given priority; although the power and stability of the current vehicle-mounted and object-mounted wireless transmission modules have been greatly improved, the characteristic of short distance without direct link is always avoided. Therefore, it is considered to connect these wireless transmission modules to each other through relay forwarding and amplification. Although there is also video transmission by broadcasting, due to the large video resources, there are also problems such as large frequency band occupation, large resource consumption and poor video quality. Therefore, it is still considered to establish a point-to-point transmission method. The present invention adjusts the spatial layout structure of the mobile device to a frequency band cross structure through a preset method to reduce the mutual interference between the relay devices at each stage; and allocates the number of receiving links and the number of sending links according to the ratio of the total receiving bit rate to the total sending bit rate of the relay device at the stage to optimize the transmission efficiency between the relay device and the main device; and adjusts the connection link communication channel width according to the number of relay device connection links; and calculates the relationship between the transmission rate and the video stream bit rate to readjust the relay device connection layout method.

[0061] like Figure 1 As shown, this embodiment provides a video transmission method, characterized in that the method includes:

[0062] S1. The multi-path wireless connection function of the mobile device is turned on and allows access and access, so that the mobile device can wirelessly connect to multiple other devices or be connected by multiple other devices, and the receiving links and transmitting links of the mobile device are not less than the preset number respectively;

[0063] S2. Mobile devices preferentially connect to other devices that are closer to each other. The central device obtains the mutual connection status and connection distance between the mobile devices to obtain the spatial layout structure between the mobile devices and adjusts the spatial layout structure to a phased frequency band cross structure through a preset method.

[0064] S3, dividing the wireless transmission frequency band into three sub-bands, fixing the wireless transmission frequency band of the mobile device in the same stage to any one of the above three sub-bands, and making the transmission frequency bands of the mobile devices in adjacent stages different from each other; when the stage mobile device receives the video stream signal, adjusting the received signal to the transmission frequency within the allocated frequency band and forwarding and amplifying it;

[0065] S4. Allocate the link quantity and link width of mobile devices at different stages according to a preset channel allocation method, and automatically stagger the channel frequencies of mobile devices at the same stage in space according to a wireless transmission protocol;

[0066] S5. When the central device receives video stream signals from other mobile devices or sends video stream signals to other mobile devices through the above method, it detects the total bit rate and total transmission rate of the video stream transmitted by the mobile devices in each stage according to the preset time interval, and readjusts the spatial layout structure of the mobile devices in each stage according to the relationship between the total bit rate and the total transmission rate.

[0067] For example, in an intelligent transportation system, multiple vehicles are equipped with multi-path wireless connection functions. These vehicles can discover and connect to other vehicles that are close to each other to form a dynamic inter-vehicle network. A central device similar to a central intelligent control system can obtain the interconnection status and distance information of all connected vehicles in real time, and then build a spatial layout structure of the inter-vehicle network. Each on-board mobile device has at least 2 receiving links and transmitting links respectively, so as to avoid interruption of video stream signal transmission in a certain direction due to failure of a single device, which helps to improve the stability and reliability of the overall communication. The central device adjusts this spatial layout structure to a frequency band cross structure according to a preset method to optimize the transmission efficiency and reliability of wireless signals. In the frequency band cross structure, different wireless transmission frequency bands are allocated to the mobile devices in the stage, such as transmission frequency band one, transmission frequency band two and transmission frequency band three. The transmission frequency of the mobile devices in the same stage can only be selected from one of the frequency bands, and the mobile devices in adjacent stages use different frequency bands to ensure that different stages do not interfere with each other. When the mobile device receives a wireless signal from another mobile device, it will adjust the received signal to the transmission frequency within the allocated frequency band and forward and amplify it to ensure that the video stream signal can be effectively transmitted. The central equipment will seamlessly stitch and integrate the received video signals in a panoramic manner, and after digital processing, transmit the processed video signals to other devices, so that each vehicle can obtain the real-time traffic conditions around the intersection and adjust the driving strategy in real time, thereby improving the efficiency and safety of the entire transportation system.

[0068] Furthermore, the method further includes: the layout of the phased frequency band cross structure is as follows: assuming that the maximum connection distance between mobile devices is M, and the distance between mobile devices in adjacent stages is d ij , where i is different stages, j is different equipment in the same stage, and d ij ≤M; the mobile devices at different stages are adjusted according to the distribution situation and present as irregular surrounding bands centered on the central device; the one closest to the central device is the first stage, and the frequency band of stage i is r i , then the frequency band allocation method is: i =mod(i,3).

[0069] Exemplarily, the frequency band allocation method of mobile devices in each stage adopts a cyclic allocation, for example, the first stage is allocated to frequency band one, the second stage is allocated to frequency band two, the third stage is allocated to frequency band three, the fourth stage is allocated to frequency band one, and so on. The second stage only accepts data signals from frequency band one and only sends data signals from frequency band two, the third stage only accepts data signals from frequency band two and only sends data signals from frequency band three, and the fourth stage only accepts data signals from frequency band three and only sends data signals from frequency band one. Because the fourth stage is far away from the first stage, when the data signal attenuates, it is ensured that the data signals of different stages in the irregular circular surround band do not interfere with each other.

[0070] Further, the method also includes: the way of allocating the link quantity and link width of mobile devices at different stages according to the preset channel allocation method is: obtaining the total bit rate of video stream data received by the mobile device at the stage and the total bit rate of video stream data sent by the mobile device at the stage, calculating the average number of receiving links and the average number of sending links according to the ratio between the total receiving bit rate and the total sending bit rate as the number of receiving links and the number of sending links of the mobile device at the stage respectively, and allocating the connection link width according to the number of connection links, and the calculation formula of the average number of receiving links of the mobile device at the stage is:

[0071]

[0072] The formula for calculating the average number of transmission links is:

[0073]

[0074] Where T ij is the number of receiving links of the mobile device in the stage, S ij is the number of sending links, TV ij is the receiving transmission rate, SV ij is the sending transmission rate, is the average number of receiving links of the mobile device in the stage, is the average number of sending links, is the average receiving transmission rate, is the average transmission rate, P ij is the total power of data transmission by the mobile device in the stage and P ij =∑ j (S ij ×SV ij )+∑ j (T ij ×TV ij ); The sum of the number of receiving links and the number of sending links is less than or equal to the upper threshold A of the number of other devices that the mobile device can effectively connect to, that is, T ij +S ij ≤A.

[0075] Exemplarily, when the central device receives video stream signals transmitted by other mobile devices or transmits video stream signals to other mobile devices, the video stream data required to be transmitted by the mobile device close to the central device is larger than the video stream data required to be transmitted by the mobile device far from the central device. For example, in a fleet of autonomous vehicles, the central controller, i.e., the central device, is set in the middle, and the vehicles at both ends need to transmit real-time video information around the vehicle to the central device. Assuming that the vehicles at both ends are in the third stage, the third-stage vehicle only needs to transmit the third-stage video data to the second-stage vehicle, the second-stage vehicle needs to transmit the second and third-stage vehicle video data to the first-stage vehicle, and the first-stage vehicle needs to transmit the first, second, and third-stage vehicle video data to the central device. In order to improve transmission efficiency, the vehicles at each stage will dynamically adjust the number of receiving links and the number of sending links according to the size of the video stream to be transmitted and the difference in the transmission rate of the receiving link and the sending link.

[0076] Furthermore, the method further includes: the manner of allocating the connection link width according to the number of connection links is: the channel width in the current wireless communication standard protocol is fixed, and the mobile device bundles multiple adjacent or non-adjacent channels together through channel bundling to adjust the link width and increase the bandwidth and video stream transmission rate; according to the connection link width W ij The calculation formula for the width of the connection link, which is in inverse proportion to the number of connection links n, is:

[0077] W ij =F(n)=ω1×e ―α·n +b1;

[0078] Among them, ω1 is a coefficient obtained by the maximum likelihood estimation method, α is a constant obtained by the maximum likelihood estimation method, b1 is a bias obtained by the maximum likelihood estimation method, and the independent variable link number n is the average number of receiving links or the average number of sending links obtained by the above method, that is, or And the total link width of the mobile devices in the same stage is also within the frequency band width allocated in that stage, that is, ∑ j W ij ∈r i .

[0079] For example, in the scenario of narrow branch roads in the Internet of Vehicles, if the number of transmission links established between the mobile device at this location and the mobile devices at other stages or the central device is small, a larger link width is allocated to the transmission link according to the above functional relationship, thereby improving the overall performance of the Internet of Vehicles. In the scenario of main roads in the Internet of Vehicles, if the number of mobile devices far from the central device is large and the number of transmission links is large, a smaller link width is allocated to the transmission link according to the above functional relationship, and the spatial layout structure of the mobile device is adjusted when the transmission rate corresponding to the link width is less than the video stream bit rate.

[0080] Furthermore, the method further comprises: the way of re-adjusting the spatial layout structure according to the relationship between the total bit rate and the total transmission rate is: obtaining the distance d between the mobile devices in the adjacent stages ij , the bit rate of the video stream transmitted by the mobile device is B ij , according to the positive proportional relationship between link transmission rate and link width and the need to exclude link isolation width, the link transmission rate function is constructed as:

[0081]

[0082] Where ω2 is the coefficient obtained by maximum likelihood estimation, R ij is the signal-to-noise ratio of the link, f is the average frequency of the link signal, and substituting into the link width formula yields:

[0083]

[0084] When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is greater than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is shortened according to a preset ratio. When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is less than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is increased according to a preset ratio. The calculation method is:

[0085]

[0086] in is the average distance between mobile devices in adjacent stages after replanning, is the average distance between mobile devices in adjacent stages before replanning, ω3 is the preset safety proportional coefficient and ω3<1.

[0087] For example, in the Internet of Vehicles scenario, the central device needs to send video signals to multiple mobile devices. Five mobile devices in the first phase are connected to 20 mobile devices in the second phase within an interval of 200 meters. When it is detected that the average receiving rate of the second phase mobile devices is less than the video stream bit rate, the number of sending links of the first phase mobile devices is reduced, and the distance with the second phase mobile devices is shortened. The number of planned stages can be increased when appropriate. The spatial layout structure between mobile devices is readjusted to five mobile devices in the first phase connected to eight mobile devices in the second phase within an interval of 100 meters, and eight mobile devices in the second phase connected to 12 mobile devices in the third phase within an interval of 100 meters, to solve the problem of insufficient transmission rate of the receiving link and severe signal attenuation over long distances.

[0088] Based on the same inventive concept, Figure 2 As shown, this embodiment also provides a video transmission system, the system includes a wireless connection module, a connection adjustment module, a signal forwarding module, a channel sub-allocation module 1, a channel sub-allocation module 2 and a transmission detection module; the wireless connection module is connected to the connection adjustment module, the signal forwarding module is connected to the transmission detection module, and the channel sub-allocation module 1 is connected to the channel sub-allocation module 2;

[0089] A wireless connection module, wherein the multi-path wireless connection function of the mobile device is turned on and allows access and access, so that the mobile device can wirelessly connect to multiple other devices or be connected by multiple other devices, and the receiving links and transmitting links of the mobile device are not less than a preset number respectively;

[0090] A connection adjustment module is used for mobile devices to preferentially connect to other devices that are closer. The central device obtains the mutual connection status and connection distance between the mobile devices to obtain the spatial layout structure between the mobile devices and adjusts the spatial layout structure to a phased frequency band cross structure through a preset method.

[0091] The signal forwarding module is used to divide the wireless transmission frequency band into three sub-bands, fix the wireless transmission frequency band of the mobile device in the same stage to any one of the above three sub-bands, and the transmission frequency bands of the mobile devices in adjacent stages are different from each other; when the stage mobile device receives the video stream signal, the received signal is adjusted to the transmission frequency within the allocated frequency band and forwarded and amplified;

[0092] The channel sub-allocation modules 1 and 2 are used to allocate the link quantity and link width of mobile devices at different stages according to a preset channel allocation method, and the channel frequencies of mobile devices at the same stage are automatically staggered in space according to the wireless transmission protocol;

[0093] The transmission detection module is used to detect the total bit rate and total transmission rate of the video stream transmitted by the mobile devices in each stage according to the preset time interval when the central device receives the video stream signal of other mobile devices or sends the video stream signal to other mobile devices through the above method, and readjust the spatial layout structure of the mobile devices in each stage according to the relationship between the total bit rate and the total transmission rate.

[0094] Furthermore, the system further comprises: a connection adjustment module, which is used for the layout of the phased frequency band cross structure: assuming that the maximum connection distance between mobile devices is M, and the distance between mobile devices in adjacent stages is d ij , where i is different stages, j is different equipment in the same stage, and d ij ≤M; the mobile devices at different stages are adjusted according to the distribution situation and present as irregular surrounding bands centered on the central device; the one closest to the central device is the first stage, and the frequency band of stage i is r i , then the frequency band allocation method is: i =mod(i,3).

[0095] Furthermore, the system further includes: a channel allocation submodule 1, which is used to allocate the link quantity and link width of mobile devices at different stages according to a preset channel allocation method in the following manner: the total bit rate of video stream data received by the mobile device at the stage and the total bit rate of video stream data sent by the mobile device at the stage are obtained, and the average number of receiving links and the average number of sending links are calculated according to the ratio between the total receiving bit rate and the total sending bit rate as the number of receiving links and the number of sending links of the mobile device at the stage respectively, and the connection link width is allocated according to the number of connection links. The calculation formula for the average number of receiving links of the mobile device at the stage is:

[0096]

[0097] The formula for calculating the average number of transmission links is:

[0098]

[0099] Where T ij is the number of receiving links of the mobile device in the stage, S ij is the number of sending links, TV ij is the receiving transmission rate, SV ij is the sending transmission rate, is the average number of receiving links of the mobile device in the stage, is the average number of sending links, is the average receiving transmission rate, is the average transmission rate, P ij is the total power of data transmission by the mobile device in the stage and P ij =∑j (S ij ×SV ij )+∑ j (T ij ×TV ij ); The sum of the number of receiving links and the number of sending links is less than or equal to the upper threshold A of the number of other devices that the mobile device can effectively connect to, that is, T ij +S ij ≤A.

[0100] Furthermore, the system further comprises: a channel allocation submodule 2, which is used to allocate the connection link width according to the number of connection links in the following manner: the channel width is fixed in the current wireless communication standard protocol, and the mobile device bundles multiple adjacent or non-adjacent channels together through channel bundling to adjust the link width and increase the bandwidth and video stream transmission rate; according to the connection link width W ij The calculation formula for the width of the connection link, which is in inverse proportion to the number of connection links n, is:

[0101] W ij =F(n)=ω1×e ―α·n +b1;

[0102] Among them, ω1 is a coefficient obtained by the maximum likelihood estimation method, α is a constant obtained by the maximum likelihood estimation method, b1 is a bias obtained by the maximum likelihood estimation method, and the independent variable link number n is the average number of receiving links or the average number of sending links obtained by the above method, that is, or And the total link width of the mobile devices in the same stage is also within the frequency band width allocated in that stage, that is, ∑ j W ij ∈r i .

[0103] Furthermore, the system further comprises: a transmission detection module, which is used to readjust the spatial layout structure according to the relationship between the total bit rate and the total transmission rate by obtaining the distance d between the mobile devices in the adjacent stages. ij , the bit rate of the video stream transmitted by the mobile device is B ij , according to the positive proportional relationship between link transmission rate and link width and the need to exclude link isolation width, the link transmission rate function is constructed as:

[0104]

[0105] Where ω2 is the coefficient obtained by maximum likelihood estimation, R ij is the signal-to-noise ratio of the link, f is the average frequency of the link signal, and substituting into the link width formula yields:

[0106]

[0107] When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is greater than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is shortened according to a preset ratio. When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is less than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is increased according to a preset ratio. The calculation method is:

[0108]

[0109] in is the average distance between mobile devices in adjacent stages after replanning, is the average distance between mobile devices in adjacent stages before replanning, ω3 is the preset safety proportional coefficient and ω3<1.

[0110] It should be noted that, regarding the system in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

Claims

1. A video transmission method, characterized in that: The method comprises: S1. The multi-path wireless connection function of the mobile device is turned on and allows access and access, so that the mobile device can wirelessly connect to multiple other devices or be connected by multiple other devices, and the receiving links and transmitting links of the mobile device are not less than the preset number respectively; S2. Mobile devices preferentially connect to other devices that are closer to each other. The central device obtains the mutual connection status and connection distance between the mobile devices to obtain the spatial layout structure between the mobile devices and adjusts the spatial layout structure to a phased frequency band cross structure through a preset method. S3, dividing the wireless transmission frequency band into three sub-bands, fixing the wireless transmission frequency band of the mobile device in the same stage to any one of the above three sub-bands, and making the transmission frequency bands of the mobile devices in adjacent stages different from each other; when the stage mobile device receives the video stream signal, adjusting the received signal to the transmission frequency within the allocated frequency band and forwarding and amplifying it; S4. Allocate the link quantity and link width of mobile devices at different stages according to a preset channel allocation method, and automatically stagger the channel frequencies of mobile devices at the same stage in space according to a wireless transmission protocol; S5. When the central device receives video stream signals from other mobile devices or sends video stream signals to other mobile devices through the above method, it detects the total bit rate and total transmission rate of the video stream transmitted by the mobile devices in each stage according to the preset time interval, and readjusts the spatial layout structure of the mobile devices in each stage according to the relationship between the total bit rate and the total transmission rate.

2. A video transmission method as claimed in claim 1, characterized in that: The layout of the phased frequency band cross structure is as follows: assuming that the maximum connection distance between mobile devices is M, and the distance between mobile devices in adjacent stages is d ij , where i is different stages, j is different equipment in the same stage, and d ij ≤M; the mobile devices at different stages are adjusted according to the distribution situation and present as irregular surrounding bands centered on the central device; the one closest to the central device is the first stage, and the frequency band of stage i is r i , then the frequency band allocation method is: i =mod(i,3).

3. A video transmission method as claimed in claim 1, characterized in that: The method of allocating the link quantity and link width of mobile devices at different stages according to the preset channel allocation method is as follows: the total bit rate of video stream data received by the mobile device at the stage and the total bit rate of video stream data sent by the mobile device at the stage are obtained, and the average number of receiving links and the average number of sending links are calculated according to the ratio between the total receiving bit rate and the total sending bit rate as the number of receiving links and the number of sending links of the mobile device at the stage, respectively, and the connection link width is allocated according to the number of connection links. The calculation formula of the average number of receiving links of the mobile device at the stage is: The formula for calculating the average number of transmission links is: Where T ij is the number of receiving links of the mobile device in the stage, S ij is the number of sending links, TV ij is the receiving transmission rate, SV ij is the sending transmission rate, is the average number of receiving links of the mobile device in the stage, is the average number of sending links, is the average receiving transmission rate, is the average transmission rate, P ij is the total power of data transmission by the mobile device in the stage and P ij =∑ j (s ij ×SV ij )+∑ j (T ij ×TV ij ); The sum of the number of receiving links and the number of sending links is less than or equal to the upper threshold A of the number of other devices that the mobile device can effectively connect to, that is, T ij +S ij ≤A.

4. A video transmission method as claimed in claim 3, characterized in that: The method of allocating the connection link width according to the number of connection links is as follows: in the current wireless communication standard protocol, the channel width is fixed, and the mobile device bundles multiple adjacent or non-adjacent channels together through channel bundling to adjust the link width and increase the bandwidth and video stream transmission rate; according to the connection link width W ij The calculation formula for the width of the connection link, which is in inverse proportion to the number of connection links n, is: IN ij =F(n)=ω1×e ―α·n +b1; Among them, ω1 is a coefficient obtained by the maximum likelihood estimation method, α is a constant obtained by the maximum likelihood estimation method, b1 is a bias obtained by the maximum likelihood estimation method, and the independent variable link number n is the average number of receiving links or the average number of sending links obtained by the above method, that is, or And the total link width of the mobile devices in the same stage is also within the frequency band width allocated in that stage, that is, ∑ j W ij ∈r i .

5. A video transmission method as claimed in claim 1, characterized in that: The method of re-adjusting the spatial layout structure according to the relationship between the total bit rate and the total transmission rate is as follows: obtaining the distance d between the mobile devices in the adjacent stages ij , the bit rate of the video stream transmitted by the mobile device is B ij , according to the positive proportional relationship between link transmission rate and link width and the need to exclude link isolation width, the link transmission rate function is constructed as: Where ω2 is the coefficient obtained by maximum likelihood estimation, R ij is the signal-to-noise ratio of the link, f is the average frequency of the link signal, and substituting into the link width formula yields: When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is greater than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is shortened according to a preset ratio. When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is less than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is increased according to a preset ratio. The calculation method is: in is the average distance between mobile devices in adjacent stages after replanning, is the average distance between mobile devices in adjacent stages before replanning, ω3 is the preset safety proportional coefficient and ω3<1.

6. A video transmission system, characterized in that: The system comprises a wireless connection module, a connection adjustment module, a signal forwarding module, a channel sub-allocation module 1, a channel sub-allocation module 2 and a transmission detection module; the wireless connection module is connected to the connection adjustment module, the signal forwarding module is connected to the transmission detection module, and the channel sub-allocation module 1 is connected to the channel sub-allocation module 2; A wireless connection module, wherein the multi-path wireless connection function of the mobile device is turned on and allows access and access, so that the mobile device can wirelessly connect to multiple other devices or be connected by multiple other devices, and the receiving links and transmitting links of the mobile device are not less than a preset number respectively; A connection adjustment module is used for mobile devices to preferentially connect to other devices that are closer. The central device obtains the mutual connection status and connection distance between the mobile devices to obtain the spatial layout structure between the mobile devices and adjusts the spatial layout structure to a phased frequency band cross structure through a preset method. The signal forwarding module is used to divide the wireless transmission frequency band into three sub-bands, fix the wireless transmission frequency band of the mobile device in the same stage to any one of the above three sub-bands, and the transmission frequency bands of the mobile devices in adjacent stages are different from each other; when the stage mobile device receives the video stream signal, the received signal is adjusted to the transmission frequency within the allocated frequency band and forwarded and amplified; The channel sub-allocation modules 1 and 2 are used to allocate the link quantity and link width of mobile devices at different stages according to a preset channel allocation method, and the channel frequencies of mobile devices at the same stage are automatically staggered in space according to the wireless transmission protocol; The transmission detection module is used to detect the total bit rate and total transmission rate of the video stream transmitted by the mobile devices in each stage according to the preset time interval when the central device receives the video stream signal of other mobile devices or sends the video stream signal to other mobile devices through the above method, and readjust the spatial layout structure of the mobile devices in each stage according to the relationship between the total bit rate and the total transmission rate.

7. A video transmission system as claimed in claim 6, characterized in that: The system also includes: a connection adjustment module, which is used for the layout of the phased frequency band cross structure: assuming that the maximum connection distance between mobile devices is M, and the distance between mobile devices in adjacent stages is d ij , where i is different stages, j is different equipment in the same stage, and d ij ≤M; the mobile devices at different stages are adjusted according to the distribution situation and present as irregular surrounding bands centered on the central device; the one closest to the central device is the first stage, and the frequency band of stage i is r i , then the frequency band allocation method is: i =mod(i,3).

8. A video transmission system as claimed in claim 6, characterized in that: The system further includes: a channel allocation submodule 1, which is used to allocate the link quantity and link width of mobile devices at different stages according to a preset channel allocation method in the following manner: the total bit rate of video stream data received by the mobile device at the stage and the total bit rate of video stream data sent by the mobile device at the stage are obtained, and the average number of receiving links and the average number of sending links are calculated according to the ratio between the total receiving bit rate and the total sending bit rate as the number of receiving links and the number of sending links of the mobile device at the stage respectively, and the connection link width is allocated according to the number of connection links, and the calculation formula of the average number of receiving links of the mobile device at the stage is: The formula for calculating the average number of transmission links is: Where T ij is the number of receiving links of the mobile device in the stage, S ij is the number of sending links, TV ij is the receiving transmission rate, SV ij is the sending transmission rate, is the average number of receiving links of the mobile device in the stage, is the average number of sending links, is the average receiving transmission rate, is the average transmission rate, P ij is the total power of data transmission by the mobile device in the stage and P ij =∑ j (S ij ×SV ij )+∑ j (T ij ×TV ij ); The sum of the number of receiving links and the number of sending links is less than or equal to the upper threshold A of the number of other devices that the mobile device can effectively connect to, that is, T ij +S ij ≤A.

9. A video transmission system as claimed in claim 7, characterized in that: The system further includes: a second channel allocation submodule, which is used to allocate the connection link width according to the number of connection links in the following manner: the channel width is fixed in the current wireless communication standard protocol, and the mobile device bundles multiple adjacent or non-adjacent channels together through channel bundling to adjust the link width and increase the bandwidth and video stream transmission rate; according to the connection link width W ij The calculation formula for the width of the connection link, which is in inverse proportion to the number of connection links n, is: IN ij =F(n)=ω1×e ―α·n +b1; Among them, ω1 is a coefficient obtained by the maximum likelihood estimation method, α is a constant obtained by the maximum likelihood estimation method, b1 is a bias obtained by the maximum likelihood estimation method, and the independent variable link number n is the average number of receiving links or the average number of sending links obtained by the above method, that is, or And the total link width of the mobile devices in the same stage is also within the frequency band width allocated in that stage, that is, ∑ j W ij ∈r i .

10. A video transmission system as claimed in claim 6, characterized in that: The system further comprises: a transmission detection module for re-adjusting the spatial layout structure according to the relationship between the total bit rate and the total transmission rate by: obtaining the distance d between the mobile devices in the adjacent stages ij , the bit rate of the video stream transmitted by the mobile device is B ij , according to the positive proportional relationship between link transmission rate and link width and the need to exclude link isolation width, the link transmission rate function is constructed as: Where ω2 is the coefficient obtained by maximum likelihood estimation, R ij is the signal-to-noise ratio of the link, f is the average frequency of the link signal, and substituting into the link width formula yields: When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is greater than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is shortened according to a preset ratio. When the central device detects that the total bit rate of the video stream sent by the mobile device at each stage is less than the total transmission rate of the mobile device, the average distance between the mobile device and the central device at each stage is increased according to a preset ratio. The calculation method is: in is the average distance between mobile devices in adjacent stages after replanning, is the average distance between mobile devices in adjacent stages before replanning, ω3 is the preset safety proportional coefficient and ω3<1.

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