Downlink data transmission method, device, storage medium and electronic device

Abstract

An embodiment of the present invention provides a downlink data transmission method, apparatus, storage medium, and electronic device. The method includes: determining a transmission delay, where the transmission delay includes the sum of an optical fiber transmission delay and a downlink processing delay from a Media Access Control (MAC) egress to the air interface; determining a frame start time of the MAC egress according to the transmission delay; and transmitting downlink data according to the frame start time. By means of the present invention, the problems of large cache and low downlink download throughput in the related art during delay compensation are solved, and the effect of compensating for the optical fiber transmission delay is achieved.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of communications, and more particularly, to a downlink data transmission method, apparatus, storage medium, and electronic device. Background Art

[0002] When deploying radio access network devices in engineering, the baseband processing unit (BBU) and the active antenna unit (AAU) / remote radio unit (RRU) are usually deployed separately. The BBU is placed in a high-density communication machine room environment and is connected to the AAU placed on the iron tower or the RRU under the iron tower through fiber optic remote connection. To avoid uplink and downlink channel interference between cells, the air interface transceiver clocks of wireless cellular networking need to be aligned. Here, the transceiver clock refers to the time when the signal is sent or received from the AAU / RRU. In the downlink direction, when networking with different fiber lengths, in order to align the data sent from all AAUs / RRUs at the air interface, compensation needs to be performed according to the maximum fiber length, that is, data is sent from the BBU according to the maximum possible transmission delay.

[0003] A common method for downlink fiber length compensation is to insert a fiber delay compensation cache in the link after downlink bit-level processing, so that the sum of the transmission delay of the data on the fiber and the residence delay in the cache remains unchanged. However, this method brings two problems: (1) In the long-distance and multi-antenna scenarios, the cache required for compensation is very large. Whether the compensation cache is placed in the BBU, or in the AAU / RRU, or a part is placed in the BBU and a part in the AAU / RRU, it will affect the cache overhead of the BBU or AAU / RRU, resulting in an increase in hardware cost and power consumption; (2) In the long-distance scenario, it will also compress the processing time of each component in the baseband, especially the bit-level processing time of the PHY layer, directly affecting the bit-level Turbo / Ldpc / Polar coding throughput and reducing the downlink download throughput of the terminal.

[0004] It can be seen that in the related art, there are problems of large cache and low downlink download throughput during delay compensation.

[0005] In view of the above problems in the related art, no effective solution has been proposed yet. Summary of the Invention

[0006] Embodiments of the present invention provide a downlink data transmission method, apparatus, storage medium, and electronic device, so as to at least solve the problems of large cache and low downlink download throughput in the related art during delay compensation.

[0007] According to an embodiment of the present invention, a downlink data transmission method is provided, including: determining a transmission delay, where the transmission delay includes the sum of an optical fiber transmission delay and a downlink processing delay from a Media Access Control (MAC) egress to the air interface; determining a frame starting time of the MAC egress according to the transmission delay; and transmitting downlink data according to the frame starting time.

[0008] According to another embodiment of the present invention, a downlink data transmission device is provided, including: a first determination module configured to determine a transmission delay, where the transmission delay includes the sum of an optical fiber transmission delay and a downlink processing delay from a Media Access Control (MAC) egress to the air interface; a second determination module configured to determine a frame starting time of the MAC egress according to the transmission delay; and a transmission module configured to transmit downlink data according to the frame starting time.

[0009] According to still another embodiment of the present invention, a computer-readable storage medium is further provided, where a computer program is stored in the computer-readable storage medium, and the computer program is configured to execute the steps in any one of the above method embodiments when running.

[0010] According to still another embodiment of the present invention, an electronic device is further provided, including a memory and a processor, where a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0011] Through the present invention, after determining the sum of the optical fiber transmission delay and the downlink processing delay from a Media Access Control (MAC) egress to the air interface, the frame starting time of the MAC egress is determined according to the transmission delay, and downlink data is transmitted according to the frame starting time. By adjusting the frame starting time of the MAC egress, optical fiber transmission delay compensation can be completed. Therefore, the problems of large cache and low downlink download throughput in the related art during delay compensation can be solved, and the effect of compensating for the optical fiber transmission delay can be achieved. [[ID=I3]] Description of the Drawings

[0012] Figure 1 is a flowchart of a downlink data transmission method according to an embodiment of the present invention;

[0013] Figure 2 is a flowchart of a delay compensation principle according to an exemplary embodiment of the present invention;

[0014] Figure 3 is a schematic diagram of downlink optical fiber delay compensation according to a specific embodiment of the present invention;

[0015] Figure 4 is a structural block diagram of a downlink data transmission device according to an embodiment of the present invention. Detailed Embodiments

[0016] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0017] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence.

[0018] In this embodiment, a downlink data transmission method is provided. Figure 1 It is a flowchart of the downlink data transmission method according to an embodiment of the present invention, as Figure 1 shown, and the process includes the following steps:

[0019] Step S102, determine the transmission delay, where the transmission delay includes the sum of the optical fiber transmission delay and the downlink processing delay from the Medium Access Control (MAC) egress to the air interface;

[0020] Step S104, determine the frame start time of the MAC egress according to the transmission delay;

[0021] Step S106, transmit downlink data according to the frame start time.

[0022] In the above embodiment, the optical fiber transmission delay can be measured, and the measured optical fiber transmission delay plus the known downlink processing delay from the MAC egress to the air interface is used as the frame start time of the downlink MAC egress. That is, the downlink frame start time of the MAC egress can be adjusted according to the optical fiber length to complete downlink optical fiber delay compensation. Among them, the frame start time is the starting point for the MAC egress to start transmitting data, and downlink data can be transmitted at the frame start time. The optical fiber transmission delay can be measured by measuring the optical fiber length, then converting it into the transmission delay and reporting it to the MAC; it can also be measured by measuring the optical fiber length, dividing the optical fiber length by n km, rounding up, and then converting it into the transmission delay and reporting it to the MAC. The MAC adjusts the downlink frame start time of the MAC egress according to the measured optical fiber delay and the known link processing delay from the MAC egress to the optical interface.

[0023] Exemplarily, the execution subject of the above steps can be the MAC, or a data processing system including the BUU and AAU / RRU, etc., or other terminal devices with similar processing functions.

[0024] Through the present invention, after determining the sum of the optical fiber transmission delay and the downlink processing delay from the Medium Access Control (MAC) egress to the air interface, the frame start time of the MAC egress is determined according to the transmission delay, and downlink data is transmitted according to the frame start time. By adjusting the frame start time of the MAC egress, optical fiber transmission delay compensation can be completed. Therefore, the problems of large cache and low downlink download throughput existing in the related art can be solved, and the effect of compensating the optical fiber transmission delay can be achieved.

[0025] In an exemplary embodiment, determining the transmission delay includes one of the following: determining the transmission delay configured by a predetermined device; determining the optical fiber transmission delay and the downlink processing delay sent by a predetermined device, and determining the sum of the optical fiber transmission delay and the downlink processing delay as the transmission delay. In this embodiment, the transmission delay can be determined by a predetermined device and then sent to the MAC. Of course, it can also be that the optical fiber transmission delay and the downlink processing delay are determined by a predetermined device, and then the above two delays are sent to the MAC, and the MAC determines the above transmission delay by summing the above two delays. Among them, the predetermined device can be a software platform or other modules, that is, the predetermined device is a device that can determine the optical fiber transmission delay and the downlink processing delay.

[0026] In an exemplary embodiment, the optical fiber transmission delay includes one of the following: a first optical fiber transmission delay, where the first optical fiber transmission delay is the ratio of the optical fiber length to the data transmission speed in the optical fiber; a second optical fiber transmission delay, where the second optical fiber transmission delay is the optical fiber transmission delay determined based on the delay range in which the ratio of the optical fiber length to the data transmission speed in the optical fiber is located. In this embodiment, the optical fiber transmission delay can be determined by the ratio of the optical fiber length to the data transmission speed in the optical fiber. It can also be determined by the delay range in which the ratio of the optical fiber length to the data transmission speed in the optical fiber is located. For example, if the ratio of the optical fiber length to the data transmission speed in the optical fiber is 3.5 μm, then the first optical fiber transmission delay is 3.5 μm. And since 3.5 μm is between 0 - 5 μm, the second optical fiber transmission delay can be determined as 5 μm. Of course, the second optical fiber transmission delay can also be the delay obtained by rounding up the ratio of the optical fiber length to the data transmission speed in the optical fiber. For example, when the ratio of the optical fiber length to the data transmission speed in the optical fiber is 3.5 μm, the second optical fiber transmission delay can be the transmission delay obtained by rounding up 3.5 μm, that is, the second optical fiber transmission delay can be 4 μm.

[0027] In the above embodiment, when the optical fiber transmission delay includes the second optical fiber transmission delay, the flowchart of the delay compensation principle can be seen in the appendix Figure 2 , as Figure 2 shown, and this process includes:

[0028] Step S202, measure the actual delay of optical fiber transmission.

[0029] Step S204, round up the actual delay of optical fiber transmission to convert it into the optical fiber transmission delay.

[0030] Step S206, add the measured optical fiber transmission delay to the known downlink processing delay from the MAC exit to the air interface as the starting frame time of the downlink MAC exit.

[0031] In an exemplary embodiment, when the optical fiber transmission delay includes the second optical fiber transmission delay, the method further includes one of the following: caching the downlink data in transmission by using a first buffer disposed at the outlet of a baseband processing unit (BBU), and when the caching time reaches a first time, continuing to transmit the downlink data, where the first time is the difference between a first value and a second value, the first value is the value obtained by rounding up the ratio of the optical fiber length to the data transmission speed in the optical fiber, and the second value is the ratio of the optical fiber length to the data transmission speed in the optical fiber; caching the downlink data in transmission by using a second buffer disposed at the inlet of an active antenna unit (AAU) / remote radio unit (RRU), and when the caching time reaches a second time, continuing to transmit the downlink data, where the second time is the difference between a first value and a second value, the first value is the value obtained by rounding up the ratio of the optical fiber length to the data transmission speed in the optical fiber, and the second value is the ratio of the optical fiber length to the data transmission speed in the optical fiber; caching the downlink data in transmission by using a first buffer disposed at the outlet of a BBU, and when the caching time reaches a first time, continuing to transmit the downlink data, and caching the downlink data in transmission by using a second buffer disposed at the inlet of an AAU or an RRU, and when the caching time reaches a second time, continuing to transmit the downlink data, where the sum of the first time and the second time is the difference between a first value and a second value, the first value is the value obtained by rounding up the ratio of the optical fiber length to the data transmission speed in the optical fiber, and the second value is the ratio of the optical fiber length to the data transmission speed in the optical fiber. In this embodiment, a small buffer, i.e., the first buffer, can be added at the BBU outlet to cache n km of data; a small buffer, i.e., the second buffer, can also be added at the AAU / RRU inlet to cache n km of data; or, a small buffer can be added at both the BBU outlet and the AAU / RRU inlet, so that the sum of the delays of the data cached in the first buffer and the second buffer is the delay of n km. It should be noted that in this embodiment, the first value can be determined by rounding up the ratio of the optical fiber length to the data transmission speed in the optical fiber, or the first optical fiber length can be determined by rounding up the length of the optical fiber, and then the first value can be determined according to the ratio of the first optical fiber length to the data transmission speed in the optical fiber. For example, when the optical fiber length is 4.5 km, the first value is obtained by rounding up the value obtained by dividing the optical fiber length by the data transmission speed in the optical fiber, or the optical fiber length can be rounded up to 5 km, and the first value is obtained by dividing 5 km by the data transmission speed in the optical fiber.

[0032] In an exemplary embodiment, the interface between the BBU and the AAU / RRU supports at least one of the following protocols: eCPRI protocol, ORAN protocol, ROE protocol, CPRI protocol.

[0033] In an exemplary embodiment, when the time delay range of the ratio of the optical fiber length to the data transmission speed in the optical fiber is between a first time delay value and a second time delay value, the second optical fiber transmission time delay is the second time delay value, where the first time delay value is less than the second time delay value, and the first time delay value and the second time delay value are pre-determined time delay values. In this embodiment, when the time delay range of the ratio of the optical fiber length to the data transmission speed in the optical fiber is between a first time delay value and a second time delay value, the second optical fiber transmission time delay can be set to the second time delay value, where the first time delay value and the second time delay value can be artificially set values, and different first time delay values and second time delay values can be set according to different cells.

[0034] The following describes how to transmit downlink data in combination with specific embodiments:

[0035] Figure 3 is a schematic diagram of adjusting the downlink start frame time at the MAC egress according to the optical fiber length to complete the downlink optical fiber time delay compensation in the optical port splitting scenario according to a specific embodiment of the present invention, as Figure 3 shown, and the time delay compensation process includes:

[0036] Step S302: Adjust the start frame time of the downlink at the MAC egress according to the measured optical fiber transmission time delay and the known downlink link processing time delay from the MAC egress to the air interface.

[0037] Step S304: Perform PHY layer bit-level processing on the signal.

[0038] Step S306: Perform PHY layer symbol-level processing on the signal after bit-level processing.

[0039] Step S308: Downlink optical fiber compensation cache for n microseconds.

[0040] Step S310: Perform intermediate radio frequency processing on the signal after symbol-level processing and transmit it through the antenna.

[0041] It should be noted that after the PHY layer symbol-level processing, the signal after symbol-level processing can be transmitted at the interface between the BBU and the AAU / RRU. Alternatively, in the PHY layer symbol-level processing, a part of the symbol level can be processed by the BBU, and the remaining part of the symbol level can be processed by the AAU / RRU. In addition, after the PHY layer bit-level processing, the signal after bit-level processing can be transmitted at the interface between the BBU and the AAU / RRU. Of course, after the MAC processing, the signal after MAC processing can also be transmitted at the interface between the BBU and the AAU / RRU.

[0042] Among them, steps S302 - S306 can be executed by the baseband processing unit, and steps S308 - S310 can be executed by the post - radio frequency processing unit.

[0043] From the above steps, it can be seen that the optical fiber length only affects the starting frame time of the MAC egress for downlink. If the optical fiber is short, the starting frame time is late; if the optical fiber is long, the starting frame time is early. There is no need to add additional compensation buffers, and the processing time of each component in the downlink is not compressed.

[0044] Exemplarily, the foregoing downlink data transmission method can be applied to the optical fiber delay compensation in a wireless communication system. Then, the optical fiber delay compensation method for the wireless communication system may include the following steps:

[0045] First step, measure the actual delay of optical fiber transmission;

[0046] Second step, round up the actual delay of optical fiber transmission to convert it into the optical fiber transmission delay;

[0047] Third step, add the rounded - up optical fiber transmission delay to the known downlink processing delay from the MAC egress to the air interface as the starting frame time of the downlink MAC egress.

[0048] Exemplarily, the foregoing downlink data transmission method can also be applied to independently adjust the starting frame time of the MAC egress in each cell. Then, the optical fiber delay compensation method for the wireless communication system may include the following steps:

[0049] First step, measure the actual delay of optical fiber transmission in cell 1;

[0050] Second step, round up the measured actual delay of optical fiber transmission in cell 1 to convert it into the optical fiber transmission delay in cell 1;

[0051] Third step, add the rounded - up optical fiber transmission delay in cell 1 to the known downlink processing delay from the MAC egress in cell 1 to the air interface as the starting frame time of the downlink MAC egress in cell 1;

[0052] Fourth step, measure the actual delay of optical fiber transmission in cell 2;

[0053] Fifth step, round up the measured actual delay of optical fiber transmission in cell 2 to convert it into the optical fiber transmission delay in cell 2;

[0054] Sixth step, add the measured optical fiber transmission delay in cell 2 to the known downlink processing delay from the MAC egress in cell 2 to the air interface as the starting frame time of the downlink MAC egress in cell 2.

[0055] It should be noted that the optical fiber lengths of different cells may be different. Therefore, the optical fiber delays corresponding to different cells may also be different.

[0056] In the foregoing embodiments, fiber optic delay compensation is achieved by adjusting the frame start time at the MAC egress (the frame start time is later when the optical fiber is short, and earlier when the optical fiber is long). This can meet the requirements of different fiber optic delay compensations without increasing the hardware cost and power consumption of the radio remote unit, without increasing the hardware cost and power consumption of the baseband processing unit, without compressing the processing time of each component in the baseband, and especially without compressing the bit-level processing time of the PHY layer.

[0057] Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by means of software plus a necessary general hardware platform. Of course, it can also be implemented by hardware, but in many cases, the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disc) and includes several instructions to enable a terminal device (which can be a computer, a server, or a network device, etc.) to execute the methods described in various embodiments of the present invention.

[0058] In this embodiment, a downlink data transmission device is also provided. This device is used to implement the above embodiments and preferred implementation manners, and those that have been described will not be repeated. As used hereinafter, the term "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0059] Figure 4 is a structural block diagram of a downlink data transmission device according to an embodiment of the present invention. As Figure 4 shown, the device includes:

[0060] A first determination module 42, configured to determine a transmission delay, where the transmission delay includes the sum of the fiber optic transmission delay and the downlink processing delay from the media access control (MAC) egress to the air interface;

[0061] A second determination module 44, configured to determine the frame start time of the MAC egress according to the transmission delay;

[0062] A transmission module 46, configured to transmit downlink data according to the frame start time.

[0063] In an exemplary embodiment, the first determination module 42 includes one of the following: a first determination unit, configured to determine the transmission delay configured by a predetermined device; a second determination unit, configured to determine the fiber optic transmission delay and the downlink processing delay sent by a predetermined device, and determine the sum of the fiber optic transmission delay and the downlink processing delay as the transmission delay.

[0064] In an exemplary embodiment, the optical fiber transmission delay includes one of the following:

[0065] The first optical fiber transmission delay, where the first optical fiber transmission delay is the ratio of the optical fiber length to the data transmission speed in the optical fiber; the second optical fiber transmission delay, where the second optical fiber transmission delay is the optical fiber transmission delay determined based on the delay range where the ratio of the optical fiber length to the data transmission speed in the optical fiber is located.

[0066] In an exemplary embodiment, when the optical fiber transmission delay includes the second optical fiber transmission delay, the device can be used for one of the following: buffering the downlink data in transmission using a first buffer provided at the outlet of the baseband processing unit BBU, and when the buffering time reaches a first time, continuing to transmit the downlink data, where the first time is the difference between a first value and a second value, the first value is the value obtained by rounding up the ratio of the optical fiber length to the data transmission speed in the optical fiber, and the second value is the ratio of the optical fiber length to the data transmission speed in the optical fiber; buffering the downlink data in transmission using a second buffer provided at the inlet of the active antenna unit AAU / remote radio unit RRU, and when the buffering time reaches a second time, continuing to transmit the downlink data, where the second time is the difference between a first value and a second value, the first value is the value obtained by rounding up the ratio of the optical fiber length to the data transmission speed in the optical fiber, and the second value is the ratio of the optical fiber length to the data transmission speed in the optical fiber; buffering the downlink data in transmission using a first buffer provided at the outlet of the baseband processing unit BBU, and when the buffering time reaches a first time, continuing to transmit the downlink data, and buffering the downlink data in transmission using a second buffer provided at the inlet of the active antenna unit AAU or remote radio unit RRU, and when the buffering time reaches a second time, continuing to transmit the downlink data, where the sum of the first time and the second time is the difference between a first value and a second value, the first value is the value obtained by rounding up the ratio of the optical fiber length to the data transmission speed in the optical fiber, and the second value is the ratio of the optical fiber length to the data transmission speed in the optical fiber.

[0067] In an exemplary embodiment, the interface between the BBU and the AAU / RRU supports at least one of the following protocols: eCPRI protocol, ORAN protocol, ROE protocol, CPRI protocol.

[0068] In an exemplary embodiment, when the delay range where the ratio of the optical fiber length to the data transmission speed in the optical fiber is located is between a first delay value and a second delay value, the second optical fiber transmission delay is the second delay value, where the first delay value is less than the second delay value, and the first delay value and the second delay value are pre-determined delay values.

[0069] It should be noted that the above-mentioned various modules can be implemented by software or hardware. For the latter, it can be implemented in the following ways, but not limited thereto: the above-mentioned modules are all located in the same processor; or, the above-mentioned various modules are respectively located in different processors in any combination form.

[0070] An embodiment of the present invention also provides a computer-readable storage medium, in which a computer program is stored. Wherein, the computer program is configured to execute the steps in any one of the above method embodiments when running.

[0071] In an exemplary embodiment, the above computer-readable storage medium may include, but is not limited to: USB flash drive, read-only memory (ROM for short), random access memory (RAM for short), mobile hard disk, magnetic disk or optical disc and other various media that can store computer programs.

[0072] An embodiment of the present invention also provides an electronic device, including a memory and a processor. A computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0073] In an exemplary embodiment, the above electronic device may further include a transmission device and an input / output device. Wherein, the transmission device is connected to the above processor, and the input / output device is connected to the above processor.

[0074] Specific examples in this embodiment may refer to the examples described in the above embodiments and exemplary embodiments, and will not be repeated here.

[0075] Obviously, those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general-purpose computing device. They can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices. They can be implemented by program codes executable by the computing device. Thus, they can be stored in a storage device and executed by the computing device. And in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules respectively, or multiple modules or steps among them can be made into a single integrated circuit module to implement. In this way, the present invention is not limited to any specific combination of hardware and software.

[0076] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A downlink data transmission method, characterized in that, Including: Determine the transmission delay, where the transmission delay includes the sum of the optical fiber transmission delay and the downlink processing delay from the Media Access Control (MAC) egress to the air interface; Determine the frame start time of the MAC egress according to the transmission delay; Transmit the downlink data according to the frame start time; Wherein, when the optical fiber transmission delay includes a second optical fiber transmission delay determined according to the delay range where the ratio of the optical fiber length to the data transmission speed in the optical fiber is located, the method further includes: caching the downlink data in transmission by using a first buffer and / or a second buffer, and after the caching time reaches a certain time, continuing to transmit the downlink data, where the first buffer is set at the egress of the Baseband Processing Unit (BBU), the second buffer is set at the ingress of the Active Antenna Unit (AAU) / Remote Radio Unit (RRU), the certain time is determined according to the difference between a first value and a second value, the first value is the value obtained by rounding up the ratio of the optical fiber length to the data transmission speed in the optical fiber, and the second value is the ratio of the optical fiber length to the data transmission speed in the optical fiber.

2. The method according to claim 1, characterized in that, Determining the transmission delay includes one of the following: Determine the transmission delay configured by a predetermined device; Determine the optical fiber transmission delay and the downlink processing delay sent by a predetermined device, and determine the sum of the optical fiber transmission delay and the downlink processing delay as the transmission delay.

3. The method according to claim 1, characterized in that, The optical fiber transmission delay further includes: A first optical fiber transmission delay, where the first optical fiber transmission delay is the ratio of the optical fiber length to the data transmission speed in the optical fiber.

4. The method according to claim 1 or 3, characterized in that Caching the downlink data in transmission by using a first buffer and / or a second buffer, and after the caching time reaches a certain time, continuing to transmit the downlink data includes one of the following: Caching the downlink data in transmission by using the first buffer, and when the caching time reaches a first time, continuing to transmit the downlink data, where the certain time includes the first time; Caching the downlink data in transmission by using the second buffer, and when the caching time reaches a second time, continuing to transmit the downlink data, where the certain time includes the second time; Caching the downlink data in transmission by using the first buffer, and when the caching time reaches a first time, continuing to transmit the downlink data, and caching the downlink data in transmission by using the second buffer, and when the caching time reaches a second time, continuing to transmit the downlink data, where the certain time includes the sum of the first time and the second time.

5. The method according to claim 1 or 4, characterized in that The interface between the BBU and the AAU / RRU supports at least one of the following protocols: eCPRI protocol, ORAN protocol, ROE protocol, CPRI protocol.

6. The method according to claim 1 or 3, characterized in that, When the delay range where the ratio of the optical fiber length to the data transmission speed in the optical fiber is located is between a first delay value and a second delay value, the second optical fiber transmission delay is the second delay value, where the first delay value is less than the second delay value, and the first delay value and the second delay value are predetermined delay values.

7. A downlink data transmission device, characterized in that, Including: A first determination module, configured to determine a transmission delay, where the transmission delay includes a sum of an optical fiber transmission delay and a downlink processing delay from a Media Access Control (MAC) egress to an air interface; A second determination module, configured to determine a frame start time of the MAC egress according to the transmission delay; A transmission module, configured to transmit downlink data according to the frame start time; Wherein, the apparatus is further configured to, when the optical fiber transmission delay includes a second optical fiber transmission delay determined according to a delay range where a ratio of an optical fiber length to a data transmission speed in the optical fiber is located, cache the downlink data in transmission by using a first cache and / or a second cache, and continue to transmit the downlink data after a caching time reaches a certain time, where the first cache is disposed at an egress of a Baseband Processing Unit (BBU), the second cache is disposed at an ingress of an Active Antenna Unit (AAU) / Remote Radio Unit (RRU), the certain time is determined according to a difference between a first value and a second value, the first value is a value obtained by rounding up a ratio of the optical fiber length to the data transmission speed in the optical fiber, and the second value is the ratio of the optical fiber length to the data transmission speed in the optical fiber.

8. The device according to claim 7, characterized in that, The first determination module includes one of the following: A first determination unit, configured to determine the transmission delay configured by a predetermined device; A second determination unit, configured to determine the optical fiber transmission delay and the downlink processing delay sent by a predetermined device, and determine a sum of the optical fiber transmission delay and the downlink processing delay as the transmission delay.

9. A computer-readable storage medium, characterized in that, A computer program is stored in the computer-readable storage medium, where the computer program is configured to execute the method described in any one of claims 1 to 6 when running.

10. An electronic device, comprising a memory and a processor, characterized in that, A computer program is stored in the memory, and the processor is configured to run the computer program to execute the method described in any one of claims 1 to 6.

Images