A method for feeding back data from the PDCP layer on the gNB side to the UPF

Abstract

The present invention discloses a method for feeding back data to UPF based on the PDCP layer on the gNB side, including: downlink data polling mechanism: on the UPF side, the lowest bit of the first byte in the DL PDU Session continer is set as the indication flag of polling; downlink data delivery status reporting mechanism: the gNB side uses the first two bytes of the three bytes of padding in the UL PDU Session continer as the average value of the difference between the Discard timer value corresponding to the first N data packets in the current pending data in the remaining receiving buffer of the feedback PDCP and the retention time of the PDCP layer, and uses the lowest bit in the first byte of the UL PDU Session continer to determine whether to carry the flag of this value. The present invention is aimed at the scenario where a QoS flow is served by multiple SDAPs. By obtaining the processing capacity and data transmission status of each base station, the UPF can better utilize the advantages of multi-base station collaboration to plan the data transmission path to ensure service quality and maximize resource utilization.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and in particular to a method for feeding back data to UPF based on the PDCP layer on the gNB side. Background Art

[0002] In order to further improve the data transmission rate and meet the millisecond-level low latency requirements, the 5G wireless network adopts a control plane and user plane separation architecture. Figure 1 As shown, 5GC (5 GenerationCore), as Figure 2 As shown in the figure, signaling is transmitted through the N2 interface, and data is transmitted between the base station and 5GC through N3.

[0003] The data is transmitted between UPF and CU_UP on the gNB side. Figure 3 The transmission and processing flow is as follows: During uplink transmission, the gNB side adds a PDU Session continer as shown in Figure 4 And GTPU header. When transmitting downlink, UPF adds PDU Session continer to the data. Figure 3 and GTPU header, and then transmit the data to the CU_UP side of the gNB through the corresponding tunnel. After receiving the data on this side, if the Discard timer is configured, the Discard timer will be started at this time. The function of this timer is to determine whether the received message can be processed normally, so as to decide whether to discard it. Due to the CU_UP processing speed, RLC buffer size and processing speed, air interface resources, and link transmission speed limitations, or the link is abnormal and not successfully released. If UPF transmits data to CU_UP with a large flow, due to the limitations of the above factors, the received data may not be processed in time, so the corresponding message Discard timer will time out and the message will be discarded.

[0004] If this situation continues, it will cause serious packet loss on the PDCP side. If there is no feedback to the core network, firstly, the transmission data will be lost, and a large amount of transmission resources will be occupied. This will cause a waste of resources. Secondly, the data loss will seriously affect the user experience. What's more, it may cause the base station to not operate normally, causing greater losses.

[0005] In addition, for the scenario where a QoS flow is served by multiple SDAPs, that is, when the same terminal performs corresponding services, and one UPF corresponds to the scenario where multiple base stations collaborate, if the UPF can know the processing capacity and data transmission status of each base station, it can better utilize the advantages of multi-base station collaboration to plan the data transmission path to ensure service quality and avoid the above situation and waste of resources. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for feeding back data from the PDCP layer on the gNB side to the UPF; to avoid the serious packet loss or abnormal release at the PDCP layer caused by the UPF sending large traffic data, but the UPF is still transmitting data to the CU, occupying transmission resources. At the same time, in a scenario where a QoS flow is served by multiple SDAPs, the UPF can make corresponding dynamic adjustments to the transmission of the QoS flow based on the feedback from each base station to achieve a more reasonable planning of related transmission, equipment and other resources; and at the same time ensure the quality of service.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A method for feeding back data from the PDCP layer on the gNB side to the UPF, including a downlink data polling mechanism and a downlink data delivery status reporting mechanism;

[0009] The downlink data polling mechanism is specifically as follows:

[0010] Step 101: On the UPF side, the least significant bit of the first byte in the DL PDU Session continer is set as the polling indication flag;

[0011] Step 102: When the UPF performs the sending process, a polling timer is started on the UPF side, and whether to set the indication flag is determined according to whether the polling timer times out; and whether there is data to be transmitted at this time. If there is data to be transmitted, the processed indication flag is sent together with the data; if there is no data to be transmitted, the processed polling indication is sent alone;

[0012] Step 103: When the gNB performs reception processing, when the GTPU entity on the gNB side successfully transmits a downlink data, the DL PDU Session continer is parsed. If the indication flag is present, the PDCP is informed to obtain the average value of the difference between the Discard timer value corresponding to the first N data currently to be processed in the receiving buffer and the retention time of the PDCP layer, and then give a corresponding response to the UPF;

[0013] The downlink data delivery status reporting mechanism is specifically as follows:

[0014] Step 201: The gNB uses the first two bytes of the three bytes of padding in the UL PDU Session continer as the average value of the difference between the Discard timer value corresponding to the first N data in the current pending data in the feedback PDCP remaining receive buffer and the retention time of the PDCP layer, and uses the least significant bit in the first byte of the UL PDU Session continer as the flag bit to determine whether to carry this value;

[0015] Step 202: On the gNB side, after the PDCP and GTPU are established, the GTPU sets the least significant bit of the first byte of the UL PDU Sessioncontiner to indicate the existence of the Buffer pending data dead time size for PDCP field, and informs the UPF side of the value of the Discard timer of the PDCP.

[0016] Step 203: During normal transmission, the GTPU parses the lowest bit of the first byte of the UL PDU Session continer. If it is "1", it indicates that the Buffer pending data dead time size for PDCP field exists, and sends a feedback report carrying the average value of the difference between the Discard timer value corresponding to the first N data currently to be processed in the buffer and the retention time of the PDCP layer to the UPF side; if it is "0", it means that the Buffer pending data dead time size for PDCP field does not exist and no feedback is provided.

[0017] Furthermore, when the indication flag is "1", it indicates that there is a polling indication; when the indication flag is "0", it indicates that there is no polling indication.

[0018] Further, judging whether to set the indication flag bit according to whether the polling timer has timed out is specifically: if the polling timer has timed out, setting the indication flag bit; if the polling timer has not timed out, not processing the indication flag bit.

[0019] Furthermore, if the value of the Discard timer is infinite, the value fed back to the UPF side is 0xffff.

[0020] Furthermore, the feedback report of the downlink data delivery status reporting mechanism also includes an active triggering mode, so that the corresponding position is filled and the corresponding indication bit is set to send feedback according to the average value of the Discard timer value corresponding to the first N data in the current pending data in the receiving buffer of the remaining receiving buffer on the gNB side and the retention time difference of the PDCP layer.

[0021] Furthermore, the transmission of the feedback report includes independent transmission and transmission by carrying data.

[0022] Beneficial effects of the present invention: The present invention adopts feedback from the gNB side to the UPF side based on the PDU Session continer. In the scenario of multi-base station collaboration, that is, a scenario where a QoS flow is served by multiple SDAPs, that is, a scenario where one UPF corresponds to multiple base stations, the UPF can dynamically adjust the transmission path and plan resources according to the feedback from each base station to ensure service quality and maximize resource utilization; at the same time, for the scenario of a single base station, it can implement flow control on the UPF side, avoiding PDCP packet loss on the gNB side or abnormal situations on the gNB side in scenarios with large traffic and weak base station processing capabilities, affecting service quality and reducing unnecessary data transmission and resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0024] Figure 1 This is a diagram showing the separation of the control plane and user plane in a 5G base station.

[0025] Figure 2 This is a diagram showing the separation of the control plane and user plane in the core network.

[0026] Figure 3 Schematic diagram of the interface between UPF and gNB.

[0027] Figure 4 This is a diagram of the downlink PDU Session continer format specified by the protocol.

[0028] Figure 5 This is a diagram of the uplink PDU Session continer format specified by the protocol.

[0029] Figure 6This is a schematic diagram of the designed downlink DL PDU Session continer format.

[0030] Figure 7 This is a schematic diagram of the designed uplink UL PDU Session continer format.

[0031] Figure 8 Flowchart of the data sending and receiving process for UPF.

[0032] Fig. 9 This is the GTPU entity processing flow chart on the gNB side. DETAILED DESCRIPTION

[0033] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0034] 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.

[0035] In this embodiment, if Figure 1 As shown, a method for feeding back data from the PDCP layer on the gNB side to the UPF includes a new downlink data polling mechanism and a new downlink data delivery status report;

[0036] A new downlink data polling mechanism: When sending downlink data, the UPF side uses the lowest bit of the first byte in the DL PDUSession continer as an indicator of the average value of the difference between the Discard timer value corresponding to the first N data currently to be processed in the PDCP layer receiving buffer and the retention time of the PDCP layer.

[0037] A new downlink data polling mechanism means that when the GTPU entity on the gNB side receives downlink data, it parses the PDUSession continer. If the polling flag exists at this time, it notifies the PDCP to promptly feedback to the UPF the average value of the difference between the Discard timer value corresponding to the first N data in the current pending data in the PDCP layer receiving buffer and the retention time of the PDCP layer. After receiving the feedback, the UPF side records it. Under the coordination of multiple base stations, the UPF distributes the data to be forwarded in a certain proportion according to the status of each base station based on the recorded feedback of each base station and the strength of the remaining processing capacity of each base station, thereby better realizing the dynamic adjustment of data transmission. If it is a single base station scenario, a dynamic adjustment method is adopted to plan data transmission based on the feedback from the base station.

[0038] A new downlink data delivery status report: The PDCP side uses the first two bytes of the three bytes reserved in the UL PDU Session continer as the average value of the difference between the Discard timer value corresponding to the first N data currently to be processed in the PDCP layer receiving buffer and the retention time of the PDCP layer, and uses the lowest bit of the first byte as the identification bit to determine whether to carry the difference;

[0039] Among them, a new downlink data delivery status report means that the gNB side needs to report the Discard timer value set by PDCP to the UPF side at the beginning of its establishment. At this time, the lowest bit of the first byte in the UL PDU Session continer is set, and the first two bytes of the reserved three bytes carry the Discard timer value of the PDCP layer on the gNB side. If the size is set to infinity, the PDCP layer feedback size is 0xffff.

[0040] Furthermore, the new downlink data delivery status report refers to the normal transmission on the gNB side after establishment, in which case the lowest bit of the first byte in the UL PDU Session continer is set, and the first two bytes of the reserved three bytes carry the average value of the difference between the Discard timer value corresponding to the first N data currently to be processed in the PDCP receiving buffer on the gNB side and the retention time of the PDCP layer.

[0041] Furthermore, the new downlink data delivery status report refers to the normal transmission on the gNB side after establishment. At this time, the lowest position of the first byte in the UL PDU Session continer is set to zero, which indicates no feedback and the corresponding feedback field does not exist.

[0042] Furthermore, the new downlink data delivery status report means that the gNB side can actively trigger feedback, or trigger feedback after receiving the trigger condition on the UPF side, thereby filling in the corresponding position and setting the corresponding indication bit to send feedback according to the average value of the Discard timer value corresponding to the first N data currently to be processed in the receiving buffer of the remaining receiving buffer on the gNB side and the retention time difference of the PDCP layer.

[0043] Furthermore, the new downlink data submission status report means that the gNB side feedback report can carry data transmission or can be transmitted separately, so as to ensure timely feedback without wasting transmission resources.

[0044] In this embodiment, Figure 6 and Figure 7 As shown, the designed downlink and uplink PDU Session continer formats;

[0045] The DL PDU Session continer format designed in this embodiment is as follows Figure 6 As shown, the processing flow is as follows Figure 8 The specific steps include:

[0046] Step 1: The UPF side starts a polling timer and determines whether to set the lowest bit of the first byte in the DL PDUSession continer according to whether the timer has timed out. Figure 6 Report polling bit in the . A "1" bit indicates that there is a polling indication, while a "0" bit indicates that there is no polling indication. In addition, it is determined whether there is data to be transmitted at this time. If there is data to be transmitted, the data is carried, otherwise it is sent separately.

[0047] Step 2: When the GTPU entity on the gNB side successfully transmits a downlink data, it parses the DL PDU Sessioncontiner. If the indication flag is present, it informs the PDCP. The PDCP obtains the average value of the difference between the Discard timer value corresponding to the first N data currently to be processed in the receiving buffer and the retention time of the PDCP layer, and then gives a corresponding response to the UPF (the value of N depends on the situation. It is recommended to take a value between 10 and 100. Too much will affect the timeliness of feedback, and too little will not be able to rule out inaccurate feedback caused by abnormal data packets. Note: The N mentioned later is the same as the N here).

[0048] The downlink data receiving side sends a status report as follows: Figure 7 As shown, the processing flow is as follows Fig. 9 The specific steps include:

[0049] Step 1: On the gNB side, after PDCP and GTPU are established, GTPU sets Buffer data status Ind to "1" through UL PDU Session continer to indicate that the Buffer pending data dead time size for PDCP field exists. The Discard timer value of PDCP is notified to the UPF side, but if the Discard timer value is infinite, the feedback value is 0xffff.

[0050] Step 2. During normal transmission, the GTPU sets the Buffer size Ind in Buffer datastatus Ind to "1" through the UL PDU Session continer to indicate that the Buffer pending data dead timesize for PDCP field exists and carries the average value of the difference between the Discard timer value corresponding to the first N data in the buffer currently pending data and the retention time of the PDCP layer. The Buffer data status Ind is "0", indicating that there is no Buffer pending data dead time size for PDCP field.

[0051] Step 3: If PDCP detects serious packet loss or other phenomena that cause serious packet loss based on the Discard timer, feedback can be automatically triggered, and the feedback value is directly set to 0.

[0052] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0053] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0054] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes. It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0055] The above description is only a preferred embodiment of the present invention and is 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 substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention. It should be noted that similar numbers and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0056] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope described in the claims.

Claims

1. A method for feeding back data from the PDCP layer on the gNB side to the UPF, characterized in that: Including downlink data polling mechanism and downlink data delivery status reporting mechanism; The downlink data polling mechanism is specifically as follows: Step 101: On the UPF side, the least significant bit of the first byte in the DL PDU Session continer is set as the polling indication flag; Step 102: When the UPF performs the sending process, a polling timer is started on the UPF side, and whether to set the indication flag is determined according to whether the polling timer times out; and whether there is data to be transmitted at this time. If there is data to be transmitted, the processed indication flag is sent together with the data; if there is no data to be transmitted, a polling indication is sent alone; Step 103: When the gNB performs reception processing and the GTPU entity on the gNB side successfully transmits a downlink data, the DL PDUSession continer is parsed. If the indication flag is present, the PDCP is informed to obtain the average value of the difference between the Discard timer value corresponding to the first N data currently to be processed in the receiving buffer and the retention time of the PDCP layer, and then give a corresponding response to the UPF; The downlink data delivery status reporting mechanism is specifically as follows: Step 201: The gNB uses the first two bytes of the three bytes of padding in the UL PDU Session continer to carry the average value of the difference between the Discard timer value corresponding to the first N data in the current pending data in the PDCP remaining receive buffer and the retention time of the PDCP layer, and uses the least significant bit in the first byte of the UL PDU Session continer to determine whether to carry the flag of this value; Step 202: On the gNB side, after the PDCP and GTPU are established, the GTPU sets the least significant bit of the first byte of the UL PDU Session continer to indicate the existence of the Buffer pending data dead time size for PDCP field, and informs the UPF side of the value of the Discard timer of the PDCP. Step 203: During normal transmission, the GTPU parses the lowest bit of the first byte of the UL PDU Session continer. If it is "1", it indicates that the Buffer pending data dead time size for PDCP field exists, and sends a feedback report carrying the average value of the difference between the Discard timer value corresponding to the first N data currently to be processed in the buffer and the retention time of the PDCP layer to the UPF side; if it is "0", it indicates that the Buffer pending data dead time size for PDCP field does not exist and no feedback is provided.

2. According to claim 1, a method for feeding back data from the gNB side PDCP layer to the UPF is characterized in that: When the indication flag is "1", it indicates that there is a polling indication; when the indication flag is "0", it indicates that there is no polling indication.

3. According to claim 1, a method for feeding back data from the gNB side PDCP layer to the UPF is characterized in that: The determining whether to set the indication flag bit according to whether the polling timer has timed out specifically includes: if the polling timer has timed out, setting the indication flag bit; if the polling timer has not timed out, not processing the indication flag bit.

4. According to claim 1, a method for feeding back data from the gNB side PDCP layer to the UPF is characterized in that: If the Discard timer value is infinite, the value fed back to the UPF side is 0xffff.

5. According to claim 1, a method for feeding back data from the gNB side PDCP layer to the UPF is characterized in that: The feedback report of the downlink data delivery status reporting mechanism also includes an active trigger mode, so that the corresponding position is filled and the corresponding indication bit is set to send feedback according to the average value of the Discard timer value corresponding to the first N data currently to be processed in the remaining receiving buffer on the gNB side and the retention time difference of the PDCP layer.

6. According to claim 1, a method for feeding back data from the gNB side PDCP layer to the UPF is characterized in that: The transmission of the feedback report includes independent transmission and transmission by carrying data.

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