Method, base station, terminal, system and medium for maintaining data compression continuity

Abstract

The present disclosure provides a method, base station, terminal, system and medium for maintaining data compression continuity, relating to the technical field of communication. The method comprises: a base station control plane entity instructing a base station user plane entity to configure or modify UDC configuration information of a bearer and notifying a terminal of a UDC applicable area; when the terminal is configured to enter an RRC inactive state and maintain UDC continuity, reserving suspended UDC configuration information, performing uplink compression on small data packets sent in the UDC applicable area, and sending the compressed small data packets and an RRC connection recovery request message to the terminal to request a base station for recovery; and the base station control plane entity instructing the base station user plane entity to determine a recovery mode of uplink data compression after receiving a context recovery request message of the base station for recovery and determining that the uplink data compression is applicable, so that the base station user plane entity decompresses the small data packets based on the reserved UDC configuration information. The present disclosure supports maintaining the continuity of uplink data compression when the terminal transmits small data packets in an RRC inactive state.

Description

Technical Field

[0001] This disclosure relates to the field of communication technology, and in particular to a method, base station, terminal, system and medium for maintaining data compression continuity. Background Technology

[0002] Limited uplink resources have become a significant concern for networks. On one hand, an increasing number of mobile terminal users are becoming content producers, exacerbating the demand for uplink resources; on the other hand, the growth in downlink traffic also leads to a corresponding increase in uplink traffic. While downlink carrier aggregation has been widely deployed, uplink carrier aggregation deployment has not been scaled up due to limitations in terminal power consumption and cost, further exacerbating the asymmetry between uplink and downlink resources.

[0003] In a typical TDD network with a high uplink / downlink ratio, the uplink can easily become a bottleneck when executing services with large uplink data volumes. Therefore, uplink enhancement is of paramount importance for TDD networks.

[0004] Meanwhile, limited uplink coverage is also a significant issue. On the one hand, as uplink traffic increases, uplink interference levels will continue to worsen. On the other hand, the size of SIP signaling during the voice service establishment phase may reach 2KB, which can lead to RLC segmentation in environments with poor channel conditions, thereby increasing voice service establishment latency or even causing voice service establishment failure.

[0005] To address the above issues, the UDC (Uplink Data Compression) scheme, as an important uplink enhancement technology, was proposed in 3GPP Rel-15 and has been standardized by 3GPP. The 3GPP UDC scheme is based on the RFC1951 DEFLATE data compression algorithm. According to the conclusions of the 3GPP RAN2#116bis meeting in January 2022, the UDC scheme is supported in 5G SA mode, and each terminal only supports two bearers configured in UDC mode. Figure 1 As shown, the UDC header and data portion are located after the SDAP header. The transmitting-side PDCP entity supports UDC compression, which occurs after packet numbering and before integrity protection or encryption. The receiving-side PDCP entity supports UDC decompression, which occurs after reordering and duplicate detection. When the RRC layer instructs the PDCP entity to re-establish, the UE needs to reset the UDC compression buffer to all zeros and pre-populate the configured dictionary into the compression buffer.

[0006] In 5G networks, UEs can reduce terminal power consumption and decrease signaling interactions between the terminal and the core network by entering an inactive state (RRC inactive state), thereby improving terminal access latency. However, as... Figure 2 As shown, in schemes prior to Rel-17, if a terminal needs to transmit small data packets, it still needs to go through the RRC recovery process to first establish the control plane before transmitting and receiving data packets. Clearly, this approach does not significantly improve access latency, and it also causes the terminal to return to an inactive state after transmitting one or more data packets. For periodic small data packet transmissions, this still increases the amount of signaling interaction between the terminal and the network. To address these issues, 3GPP conducted research on Small Data Transmission (SDT) in Rel-17, aiming to reduce access latency when the terminal transmits small data packets in an inactive state. Currently, the standard supports both RACH-based and ConfiguredGrant-based packet transmission.

[0007] The Rel-16 standard refines the process for a terminal to transition from an RRC inactive state to a connected state in a control plane and user plane separation architecture. Figure 3 This illustrates the signaling process by which a terminal transitions from a connected state to an RRC inactive state. Figure 3 As can be seen, during the triggering process, the PDCP-related entities of the base station user plane entity CU-UP need to perform a suspension operation, delete the relevant data cache, and delete the F1-U related connection with the base station detached entity DU. Furthermore, data processing for receiving or sending to the DU for that user will cease. For the DU, the relevant user context also needs to be deleted. Currently, the Rel-17 standard does not support uplink packet compression during small packet transmission.

[0008] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0009] This disclosure provides a method, base station, terminal, system, and medium for maintaining data compression continuity, which at least to some extent overcomes the technical problem that related technologies do not support maintaining uplink compression continuity when a terminal transmits small data packets in an RRC inactive state.

[0010] According to one aspect of this disclosure, a method for maintaining data compression continuity is provided, the method comprising: a first base station control plane entity instructing a first base station user plane entity to configure or modify uplink data compression UDC configuration information of a bearer via a bearer context establishment request or bearer context modification request message; when a terminal enters an RRC inactive state, instructing the first base station user plane entity on the UDC bearers that need to be suspended, and notifying the terminal of one or more pre-configured UDC application areas of the bearers via an air interface message; the first base station control plane entity configuring the terminal to maintain UDC continuity when the terminal enters an RRC inactive state, so that when the terminal is in an RRC inactive state, the terminal retains the suspended UDC bearers. The first base station's control plane entity receives the context recovery request message from the second base station. Upon receiving the context recovery request message from the second base station, it determines that the SDT is within the pre-configured uplink data compression application area and instructs the first base station's user plane entity on the uplink data compression recovery method. This enables the first base station's user plane entity to decompress the small data packets sent by the terminal based on the reserved UDC configuration information. When a small data packet needs to be sent within the pre-configured UDC application area, the reserved UDC configuration information is used to perform uplink compression.

[0011] In some embodiments, the method further includes: a first base station control plane entity sending a first data bearer (DRB) list to a first base station user plane entity via a first bearer context establishment request message or a first bearer context modification request message to request the establishment or modification of UDC configuration information included in the PDCP configuration; wherein, when the first base station is an LTE air interface, the first DRB establishment list adopts the DRB To Setup List in E-UTRAN mode; when the first base station is an NR air interface, the first DRB list adopts the DRB To Setup List included in the PDU Session Resource To Setup Modification List in NR mode.

[0012] In some embodiments, the sum of the number of uplink data compression bearers to be configured for the base station user plane entity and the number of currently activated uplink data compression bearers does not exceed a preset UDC bearer limit value, and the number of currently activated uplink data compression bearers is the number of uplink data compression bearers that have been activated but not released.

[0013] In some embodiments, the first bearer context establishment request message includes a first bearer list to be established, the first bearer list including one or more DRB bearer configuration information; the first bearer context modification request message includes a first bearer list to be established and / or a second bearer list to be modified, the first bearer list including one or more DRB bearer configuration information, the second bearer list including one or more DRB bearer configuration information, a bearer to be closed for a UDC, and a bearer to be released for a UDC.

[0014] In some embodiments, each DRB bearer configuration information includes at least the following information: 1) DRB identifier, which is an integer value; 2) SDT bearer type indication information, an enumeration type, where a value of "yes" indicates that the bearer is an SDT bearer, supporting small packet compression when the terminal is in an inactive RRC state; 3) PDCP configuration information, which includes at least the following information: PDCP re-establishment indication information, an enumeration type, where a value of "yes" indicates that the PDCP entity of the DRB needs to be rebuilt, and PDCP re-establishment information is carried only when the UDC configuration of the DRB needs to be deleted; 4) UDC configuration information, which includes at least the following information: ① UDC decompression buffer size, an enumeration type, where a value of "yes" includes at least one of the following: 2048 bytes, 4096 bytes, and 8912 bytes; ② Dictionary information, an enumeration type, where a value of "yes" includes at least one of the following: SIP-SID dictionary, custom dictionary; ③ UDC continuity indication information: an enumeration type, where a value of "yes" indicates that the PDCP entity can continue or restart the uplink data compression function during the PDCP reconstruction process.

[0015] In some embodiments, the method further includes: if, after receiving a first bearer context establishment request message from a first base station control plane entity, the first base station user plane entity finds that the UDC configuration is included in the PDCP configuration carried in the first bearer context modification request message, and the first base station user plane supports UDC configuration, then it configures the uplink data compression function of the corresponding DRB bearer using relevant parameters and returns a first bearer context establishment response message to the first base station control plane entity; if, after receiving a first bearer context modification request message from a first base station control plane entity, the first base station user plane entity finds that the UDC configuration is included in the PDCP configuration carried in the first bearer context modification request message, and the first base station user plane supports UDC configuration, then it configures the uplink data compression function of the corresponding DRB bearer using relevant parameters and returns a first bearer context modification response message to the first base station control plane entity.

[0016] In some embodiments, the method further includes: a first base station user plane entity performing bearer configuration through the following steps: checking whether the bearer configuration information of each DRB identifier in the list of bearers to be released carries UDC configuration information; if it carries UDC configuration information, then releasing the bearer corresponding to the DRB identifier; checking whether the PDCP configuration information in the bearer configuration information of each bearer in the list of bearers to be modified carries UDC configuration information; if the first base station user plane entity supports UDC capability, then configuring uplink data compression function for the bearer; if the number of configured uplink data compression bearers exceeds a preset UDC bearer upper limit, then determining that the bearer modification has failed, generating a failure reason value, the failure reason value being used to indicate that the number of UDC bearers exceeds the preset UDC bearer upper limit or that the PDCP bearer configuration cannot be supported; if the configuration information of any bearer with configured UDC function carries PDC configuration information... If the DCP re-establishment instruction information is received, all data, decompression cache, and dictionary information in the bearer are cleared. The dictionary information and decompression cache are reconfigured according to the carried UDC configuration information. If no dictionary is configured in the dictionary information, the UDC decompression cache size is set to 0; if a dictionary is configured in the dictionary information, the UDC decompression cache size is configured according to the dictionary information. The PDCP configuration information of each bearer in the requested bearer list is checked to see if it carries UDC configuration information. If the first base station user plane entity supports UDC capability, uplink data compression function is configured for the bearer. If the number of configured uplink data compression bearers exceeds the preset UDC bearer limit, the bearer establishment is determined to have failed, and a failure reason value is generated. The failure reason value is used to indicate that the number of UDC bearers exceeds the preset UDC bearer limit or that the PDCP bearer configuration cannot support it.

[0017] In some embodiments, the first bearer context establishment response message or the first bearer context modification response message includes: a bearer configuration success information list or a bearer configuration failure information list; the bearer configuration success information list is used to indicate one or more data bearers that have been successfully configured in the bearer list to be established or modified; the bearer configuration failure information list is used to indicate one or more data bearers that cannot be configured in the bearer list to be established or modified.

[0018] In some embodiments, the bearer configuration success information list includes: identifiers of one or more data bearers that have been successfully configured; the bearer configuration failure information list includes: identifiers of one or more data bearers that cannot be configured and the failure reason for each data bearer, the failure reason including: the number of UDC bearers exceeds the preset UDC bearer limit or the PDCP bearer configuration cannot be supported.

[0019] In some embodiments, the method further includes: after receiving a first bearer context establishment response message or a first bearer context modification response message from a first base station user plane entity, the first base station control plane entity determines the configuration result of the bearer to be established or modified in the first base station user plane entity; the first base station control plane entity generates a first RRC reconfiguration message to be sent to the terminal based on the configuration result, and sends the established or modified bearer configuration information to the terminal through the first RRC reconfiguration message, wherein the bearer configuration information carried in the first RRC reconfiguration message includes: UDC configuration information, and the bearer in the configuration result has a mapping relationship with the bearer in the first RRC reconfiguration message; for a bearer that needs to be added and configured as a UDC, the DRB identifier of the bearer is placed in the DRB establishment list in the RRC message; for a bearer that needs to be modified and configured as a UDC, the DRB identifier of the bearer is placed in the DRB release list and the DRB establishment list in the RRC message, and it is ensured that the sum of the number of bearers configured as UDC by the terminal after RRC reconfiguration and the number of currently active uplink data compression bearers does not exceed a preset UDC bearer upper limit value, wherein the number of currently active uplink data compression bearers is the number of uplink data compression bearers that have been activated and not released.

[0020] In some embodiments, the first RRC reconfiguration message includes at least the following information: 1) DRB release list, including one or more DRB identifiers whose UDC configuration information needs to be deleted; 2) DRB creation and modification list, including one or more DRB configuration information, each DRB configuration information including at least the following information: ① DRB identifier; ② UDC decompression cache size, enumeration type, with values ​​including at least one of the following: 2048 bytes, 4096 bytes, and 8912 bytes; ③ Dictionary information: enumeration type, with values ​​including at least one of the following: SIP-SID dictionary, custom dictionary.

[0021] In some embodiments, after the first base station control plane entity sends the successfully established or modified bearer configuration information to the terminal via a first RRC reconfiguration message, the method further includes: the terminal performing UDC configuration and reconfiguration through the following steps: for each DRB identifier in the DRB release list, delete all configuration information of the corresponding DRB, and record the number of UDC bearers to be released as T1; for each bearer in the DRB establishment or modification list that requires UDC configuration, configure the UDC decompression cache size and dictionary information, set all initial information in the cache to 0, and record the number of UDC bearers to be established as T2; If the number of UDC bearers established by the recording terminal before receiving the first RRC reconfiguration message is T0, and the value of T0-T1+T2 does not exceed the preset UDC bearer limit or no established DRB identifier is added or modified directly without being released, the UDC configuration of the bearer is determined to be successful, and the first RRC reconfiguration confirmation message is generated; if the value of T0-T1+T2 exceeds the preset UDC bearer limit or an established DRB identifier is added or modified directly without being released, the UDC configuration of the bearer is determined to be failed, and the first RRC reconfiguration failure message is generated.

[0022] In some embodiments, the method further includes: a first base station control plane entity determining the small data packet transmission bearer that needs to be suspended when the terminal enters an inactive state, and instructing the first base station user plane entity to trigger the bearer suspension process through a second bearer context modification request message, wherein the second bearer context modification request message contains at least the following information: bearer suspension indication information: an enumeration type, the values ​​of which include at least: bearer suspension, bearer resumption, and small data packet transmission resumption.

[0023] In some embodiments, the method further includes: after receiving the second bearer context modification request message, the first base station user plane entity suspends all bearers according to the suspension indication carried in the bearer suspension indication information. For bearers with configured UDC, the pre-configured decompression cache and dictionary information are maintained during the suspension period, and no clearing or resetting operation is performed on the UDC decompression cache and dictionary. The second bearer context modification response message is generated and sent to the first base station control plane entity.

[0024] In some embodiments, the method further includes: after receiving the second bearer context modification response message, the first base station control plane entity determines the uplink data compression applicable area of ​​the terminal according to the pre-configuration information, generates a second RRC reconfiguration message to be sent to the terminal, the second RRC reconfiguration message being used to instruct the terminal to maintain the uplink compression capability of the small data packet transmission bearer when entering the RRC inactive state.

[0025] In some embodiments, the second RRC reconfiguration message includes: suspended configuration information; the suspended configuration information includes at least the following information: an SDT bearer list, including one or more SDT bearer identifiers, each SDT bearer identifier being an integer value; and uplink data compression continuity indication information, an enumeration type, with a value of cell or radio access network notification area RNA.

[0026] In some embodiments, the method further includes: after receiving the second RRC reconfiguration message, the terminal configures relevant bearers according to the following process and sends a second RRC reconfiguration confirmation message back to the first base station: if the second RRC reconfiguration message contains suspended configuration information, then it is further determined whether the suspended configuration information contains an SDT bearer list; if the suspended configuration information contains an SDT bearer list, then the corresponding DRB identifier is saved, and it is determined that the bearer with the corresponding DRB identifier supports the terminal in transmitting small data packets when the RRC is not active; it is determined whether the suspended configuration information contains an uplink data compression continuity indication. Information: If the suspension configuration information includes uplink data compression continuity indication information, then all bearers that support SDT state and are configured with UDC will maintain the uplink data compression configuration when sending small data packets, continue to maintain the configured decompression cache and dictionary information, and save the configured uplink data compression applicable area; if the suspension configuration information does not include uplink data compression continuity indication information, then all bearers that support SDT state and are configured with UDC will not use uplink data compression to send small data packets when the terminal is inactive, and will clear the configured decompression cache and dictionary information.

[0027] In some embodiments, the method further includes: if the suspend configuration information does not contain an SDT bearer list, then determining that the bearer with the corresponding DRB identifier does not support the transmission of small data packets when the terminal is in RRC non-active state.

[0028] In some embodiments, the method further includes: when the terminal's SDT carries uplink data packets to be sent, caching the uplink data packets to be sent in the application layer, instructing the access layer to check whether the currently camped cell is within the pre-configured uplink data compression applicable area; if the access layer finds that the currently camped cell is within the pre-configured uplink data compression applicable area, the access layer instructs the application layer to compress the uplink data, sends the uplink data packets cached by the application layer to the terminal's PDCP layer, and according to the pre-configured dictionary information, sends the uplink data packets cached by the application layer to the compression cache to complete data compression, and then sends them to the terminal's MAC layer; when the data volume of the uplink data packets reaches a preset data volume threshold, triggering subsequent transmission operations; if the access layer finds that the currently camped cell is not within the pre-configured uplink data compression applicable area, the application layer notifies the access layer of the uplink data packets to be sent, and the access layer does not perform uplink data compression operations when sending the uplink data packets.

[0029] In some embodiments, the second base station is different from the first base station, and the method further includes: after receiving the RRC connection recovery request message and uplink data packet sent by the terminal, if the second base station finds that there is no user context information of the terminal, it caches the received uplink data packet at the MAC layer of the second base station and sends a user context acquisition request message to the control plane entity of the first base station, wherein the user context acquisition request message includes the cell identifier, downlink channel address and SDT indication information currently in which the terminal is camped.

[0030] In some embodiments, the user context acquisition request message further includes: SDT auxiliary information, which includes: one or more transmissions.

[0031] In some embodiments, the method further includes: a first base station control plane entity checking whether the cell currently camped by the terminal is within a pre-configured uplink data compression applicable area; if the first base station control plane entity finds that the cell currently camped by the terminal is within the pre-configured uplink data compression applicable area, it determines to configure the UDC transmission bearer to continue using the existing compression buffer and dictionary information for uplink data decompression operation, and returns a partial user context transfer request message to the second base station; if the first base station control plane entity finds that the cell currently camped by the terminal is not within the pre-configured uplink data compression applicable area, it sends a user context acquisition response message to the second base station.

[0032] In some embodiments, the partial user context transfer request message includes: 1) an identifier assigned to the user by the second base station on the base station interface; 2) an identifier assigned to the user by the first base station on the base station interface; 3) an SDT bearer establishment list, including: one or more SDT bearer lists, each SDT bearer list including: ① a DRB list; ② uplink user plane address information on the inter-base station interface; ③ RLC bearer configuration information of the DRB; ④ QoS information of the DRB; ⑤ RLC mode; ⑥ SN length of the RLC; ⑦ slice configuration information.

[0033] In some embodiments, the user context acquisition response message includes: 1) an identifier assigned to the user by the second base station on the base station interface; 2) an identifier assigned to the user by the first base station on the base station interface; 3) a DRB identifier list, containing one or more DRB configuration information, each DRB configuration information containing the following information: ① logical channel identifier, which is an integer value; ② RLC layer configuration information; ③ MAC layer configuration information; ④ PDCP layer configuration information.

[0034] In some embodiments, the method further includes: if the second base station receives a partial user context transfer request message, it returns a partial user context transfer response message, wherein the partial user context transfer response message contains an SDT data forwarding DRB identifier list, the SDT data forwarding DRB identifier list includes: one or more DRB configuration information, each DRB configuration information containing the following information: ① DRB identifier; ② UDC indication information, an enumeration type, where a value of "yes" indicates that the DRB is configured as a UDC; ③ Logical channel identifier, which takes the value of an integer value; ④ Downlink user plane address information of the inter-base station interface.

[0035] In some embodiments, the method further includes: after receiving a partial user context transfer request message, the first base station control plane entity sends a third bearer context modification request message to the first base station user plane entity. The third bearer context modification request message is used to request the resumption of data reception. The third bearer context modification request message contains the following information: 1) bearer suspension indication information, an enumeration type, with values ​​including at least: bearer suspension, bearer resumption, and small packet transmission resumption; 2) downlink channel address, including: IP address and port address; 3) UDC continuity indication information: a boolean type, with a value of "yes" indicating that all bearers configured as SDT bearers and configured with UDC have resumed uplink data compression continuity maintenance function.

[0036] In some embodiments, the method further includes: after receiving a third bearer context modification request message, the first base station user plane entity restores the small data packet transmission bearer of the terminal according to the small data packet transmission recovery indication information; when the value of the UDC continuity indication information is yes, it determines whether the bearer recovery of the configured UDC adopts the pre-configured cache information and dictionary information according to the second bearer configuration information; if not, it clears the pre-configured cache information and dictionary information; the first base station user plane entity allocates address information for receiving uplink data for each bearer.

[0037] In some embodiments, the method further includes: a first base station user plane entity sending a third bearer context modification response message to a first base station control plane entity to notify the first base station control plane entity that the bearer configuration has been completed.

[0038] In some embodiments, the third bearer context modification response message includes the following information: 1) a list of successfully configured bearers, including the identifiers of one or more SDT bearers; 2) the receive address information of the uplink bearer, including: IP address and port address.

[0039] In some embodiments, the method further includes: after receiving a third bearer context modification response message, the first base station control plane entity sends the uplink bearer's receive address information to the second base station through a context acquisition response message; when the first base station and the second base station are the same base station, the first base station control plane entity sends the uplink bearer's receive address information to the first base station separation entity.

[0040] In some embodiments, the method further includes: after receiving a third bearer context modification response message, the second base station sends the cached uplink data to the user plane entity of the first base station according to the receive address information of the uplink bearer.

[0041] In some embodiments, the method further includes: the first base station user plane entity completing the uplink data decompression operation based on pre-configured cache information and dictionary information, and completing the cache information and dictionary information update operation.

[0042] According to another aspect of this disclosure, a base station is also provided, comprising: a base station control plane entity and a base station user plane entity; wherein, the base station control plane entity is configured to instruct a first base station user plane entity to configure or modify uplink data compression UDC configuration information of a bearer via a bearer context establishment request or bearer context modification request message; when a terminal enters an RRC inactive state, it instructs the first base station user plane entity to suspend the UDC bearer, and notifies the terminal of one or more pre-configured UDC applicable areas of the bearer via an air interface message; the base station user plane entity is configured to configure or modify uplink data compression UDC configuration information of a bearer, and obtain the UDC bearer to be suspended when the terminal enters an RRC inactive state; when the terminal is in an RRC inactive state, the terminal retains... The suspended UDC carries UDC configuration information. When the terminal has a small data packet to send within the pre-configured UDC applicable area, the small data packet to be sent is compressed uplink using the reserved UDC configuration information. The compressed small data packet is then sent to the second base station along with the RRC connection recovery request message. The second base station is the base station from which the terminal requests RRC connection recovery. The base station control plane entity is also used to determine, after receiving the context recovery request message from the second base station, that the SDT bearer is within the pre-configured uplink data compression applicable area and instruct the first base station user plane entity on the uplink data compression recovery method. The first base station user plane entity is also used to decompress the small data packet sent by the terminal based on the reserved UDC configuration information.

[0043] According to another aspect of this disclosure, a terminal is also provided, comprising: an uplink data compression configuration information acquisition module and an uplink small data packet compression continuity maintenance module; wherein, the uplink data compression configuration information acquisition module is used to acquire one or more pre-configured UDC applicable areas of a bearer notified by a first base station control plane entity via an air interface message; the first base station control plane entity instructs a first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer via a bearer context establishment request or bearer context modification request message; the uplink small data packet compression continuity maintenance module is used to retain the UDC configuration information of the suspended UDC bearer when the terminal is in an RRC inactive state, and to maintain the uplink small data packet compression continuity maintenance module when the terminal is in an RRC inactive state. When a small data packet carried by the SDT within the pre-configured UDC application area needs to be sent, the small data packet to be sent is uplink compressed using the reserved UDC configuration information. The compressed small data packet is then sent to the second base station along with the RRC connection recovery request message. The second base station is the base station from which the terminal requests RRC connection recovery. The first base station user plane entity is also used to determine, after receiving the context recovery request message from the second base station, that the SDT is carried within the pre-configured uplink data compression application area, and instruct the first base station user plane entity on the recovery method of uplink data compression, so that the first base station user plane entity decompresses the small data packet sent by the terminal based on the reserved UDC configuration information.

[0044] According to another aspect of this disclosure, a communication system is also provided, comprising: a terminal, a first base station on which the terminal is currently camped, and a second base station for which the terminal requests RRC connection restoration; the first base station comprises: a first base station control plane entity and a first base station user plane entity; wherein, the terminal is configured to obtain one or more pre-configured UDC applicable areas of the bearers notified by the first base station control plane entity via air interface messages, and when the terminal has small data packets to be sent on the small data packet SDT bearer within the pre-configured UDC applicable area, it performs uplink compression on the small data packets to be sent using reserved UDC configuration information, and sends the compressed small data packets together with the RRC connection restoration request message to the second base station, the second base station being the base station for which the terminal requests RRC connection restoration; the first base station user plane entity is configured or modified for the bearers. The first base station control plane entity is used to instruct the first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer through a bearer context establishment request or bearer context modification request message, and to instruct the first base station user plane entity to suspend the UDC bearer when the terminal enters the RRC inactive state, and to notify the terminal of the UDC application area of ​​one or more bearers pre-configured through an air interface message; the first base station control plane entity is also used to determine that the SDT bearer is in the pre-configured uplink data compression application area after receiving the context recovery request message of the second base station, and to instruct the first base station user plane entity on the uplink data compression recovery method; the first base station user plane entity is also used to decompress small data packets sent by the terminal based on the retained UDC configuration information.

[0045] According to another aspect of this disclosure, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the method for maintaining data compression continuity as described in any of the preceding claims.

[0046] The methods, base stations, terminals, systems, and media for maintaining data compression continuity provided in the embodiments of this disclosure support uplink data compression continuity during small data packet transmission when the terminal is in an RRC inactive state in scenarios where the base station control plane and user plane are separated. This ensures that data packets can be sent quickly with minimal uplink control plane latency, while maintaining consistency in understanding the user data transmission process after the control plane and user plane are separated. It also supports using smaller data packets to improve coverage even when uplink data compression is used in an RRC inactive state, thereby improving the user experience.

[0047] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0048] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0049] Figure 1 This diagram illustrates a UDC data format in the relevant technology.

[0050] Figure 2 This diagram illustrates an RRC connection recovery process in Rel-16, a related technology.

[0051] Figure 3 This diagram illustrates the process by which a terminal transitions from an RRC connected state to an RRC inactive state in the related art.

[0052] Figure 4 This diagram illustrates an application system according to an embodiment of the present disclosure.

[0053] Figure 5 This diagram illustrates a method for maintaining data compression continuity according to an embodiment of the present disclosure.

[0054] Figure 6 This illustration shows a flowchart of a UDC configuration and modification process according to an embodiment of the present disclosure;

[0055] Figure 7 This diagram illustrates the process of a terminal transitioning from an RRC connected state to an RRC inactive state in an embodiment of this disclosure.

[0056] Figure 8 This diagram illustrates the process of a terminal transitioning from an RRC inactive state to an RRC connected state in an embodiment of this disclosure.

[0057] Figure 9 This diagram illustrates a base station according to an embodiment of the present disclosure;

[0058] Figure 10 This diagram illustrates a terminal according to an embodiment of the present disclosure;

[0059] Figure 11 This diagram illustrates a communication system according to an embodiment of the present disclosure;

[0060] Figure 12 A schematic diagram of a computer-readable storage medium according to an embodiment of the present disclosure is shown. Detailed Implementation

[0061] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0062] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0063] To facilitate understanding, before introducing the embodiments of this disclosure, the following explanations are provided for several terms involved in the embodiments of this disclosure:

[0064] 3GPP: 3rd Generation Partnership Project;

[0065] NR: New Radio;

[0066] gNB: The Next Generation NodeB;

[0067] RRC: Radio Resource Control;

[0068] CP: Control Plane;

[0069] UP: User Plane;

[0070] CU: Centralized Unit;

[0071] DU: Distributed Unit;

[0072] SDT: Small Data Transmission;

[0073] UDC: Uplink Data Compression;

[0074] RACH: Random Access Channel;

[0075] DRB: Data Radio Bearer, or simply data bearer;

[0076] SRB: Signaling Radio Bearer, or simply signaling bearer;

[0077] MAC: Medium Access Control;

[0078] RLC: Radio Link Control;

[0079] PDCP: Packet Data Convergence Protocol.

[0080] The specific implementation methods of the embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0081] Figure 4 A schematic diagram of an exemplary application system architecture is shown, illustrating an application of the method for maintaining data compression continuity as described in the embodiments of this disclosure. Figure 4 As shown, the system architecture includes a terminal 100, a network 200, and a network-side device 300.

[0082] Network 200 is a medium used to provide a communication link between terminal 100 and network-side device 300, and can be a wired network or a wireless network.

[0083] Optionally, the aforementioned wireless or wired networks use standard communication technologies and / or protocols. The network is typically the Internet, but can also be any network, including but not limited to Local Area Networks (LANs), Metropolitan Area Networks (MANs), Wide Area Networks (WANs), mobile, wired or wireless networks, private networks, or any combination of virtual private networks. In some embodiments, technologies and / or formats including Hyper Text Markup Language (HTML), Extensible Markup Language (XML), etc., are used to represent data exchanged over the network. Furthermore, conventional encryption technologies such as Secure Socket Layer (SSL), Transport Layer Security (TLS), Virtual Private Networks (VPNs), and Internet Protocol Security (IPsec) can be used to encrypt all or some links. In other embodiments, custom and / or dedicated data communication technologies can be used to replace or supplement the aforementioned data communication technologies.

[0084] Optionally, the terminal in this embodiment may also be referred to as UE (User Equipment). In specific implementation, the terminal may be a mobile phone, tablet computer, laptop computer, personal digital assistant (PDA), mobile internet device (MID), wearable device, or vehicle-mounted device, etc. It should be noted that the specific type of terminal is not limited in the embodiments of the present invention.

[0085] The network-side device 300 can be a base station, relay, or access point, etc. The base station can be a 5G or later version base station (e.g., 5G NR NB), or a base station in other communication systems (e.g., eNB base station). It should be noted that the specific type of network-side device is not limited in this embodiment of the disclosure.

[0086] Those skilled in the art will know that Figure 4The number of terminals, networks, and network-side devices shown is merely illustrative; any number of terminals, networks, and network-side devices can be included as needed. This disclosure does not limit the scope of the embodiments.

[0087] Under the above system architecture, this disclosure provides a method for maintaining data compression continuity, which can be executed by any electronic device with computing capabilities. In some embodiments, the method for maintaining data compression continuity provided in this disclosure can be implemented by the terminal and network-side devices in the above system architecture through interaction.

[0088] Figure 5 This diagram illustrates a method for maintaining data compression continuity according to an embodiment of the present disclosure, such as... Figure 5 As shown, the method for maintaining data compression continuity provided in this embodiment includes the following steps:

[0089] S502, the first base station control plane entity instructs the first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer through a bearer context establishment request or bearer context modification request message. When the terminal enters the RRC inactive state, it instructs the first base station user plane entity to suspend the UDC bearer and notifies the terminal of one or more bearer pre-configured UDC applicable areas through an air interface message.

[0090] S504, the first base station control plane entity configures the terminal to maintain UDC continuity when the terminal enters the RRC inactive state, so that when the terminal is in the RRC inactive state, the terminal retains the UDC configuration information carried by the suspended UDC, and when there is a small data packet to be sent in the small data packet SDT carried in the pre-configured UDC applicable area, the retained UDC configuration information is used to perform uplink compression operation on the small data packet to be sent, and the compressed small data packet is sent to the second base station together with the RRC connection restoration request message. The second base station is the base station from which the terminal requests the RRC connection restoration.

[0091] S506, after receiving the context recovery request message from the second base station, the first base station control plane entity determines that the SDT bearer is within the pre-configured uplink data compression applicable area, instructs the first base station user plane entity on the uplink data compression recovery method, so that the first base station user plane entity performs decompression operation on the small data packets sent by the terminal based on the retained UDC configuration information.

[0092] Figure 6 This illustration shows a flowchart of a UDC configuration and modification process according to an embodiment of the present disclosure, such as... Figure 6As shown, the base station control plane entity can instruct the first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer through a bearer context establishment request or bearer context modification request message.

[0093] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: a first base station control plane entity sends a first data bearer DRB list to a first base station user plane entity through a first bearer context establishment request message or a first bearer context modification request message to request the establishment or modification of UDC configuration information included in the PDCP configuration; wherein, when the first base station is an LTE air interface, the first DRB establishment list adopts the DRB To Setup List in E-UTRAN mode; when the first base station is an NR air interface, the first DRB list adopts the DRB To Setup List included in the PDUSESESSION Resource To Setup Modification List in NR mode.

[0094] In some embodiments, the sum of the number of uplink data compressed bearers to be configured for the base station user plane entity and the number of currently activated uplink data compressed bearers does not exceed a preset UDC bearer limit value, and the number of currently activated uplink data compressed bearers is the number of uplink data compressed bearers that have been activated but not released.

[0095] In some embodiments, the first bearer context establishment request message includes a first bearer list to be established, the first bearer list containing one or more DRB bearer configuration information; the first bearer context modification request message includes a first bearer list to be established and / or a second bearer list to be modified, the first bearer list containing one or more DRB bearer configuration information, the second bearer list containing one or more DRB bearer configuration information, a bearer to be closed for a UDC, and a bearer to be released for a UDC.

[0096] In some embodiments, each DRB bearer configuration information includes at least the following information: 1) DRB identifier, which is an integer value; 2) SDT bearer type indication information, an enumeration type, where a value of "yes" indicates that the bearer is an SDT bearer, supporting small packet compression when the terminal is in an inactive RRC state; 3) PDCP configuration information, which includes at least the following information: PDCP re-establishment indication information, an enumeration type, where a value of "yes" indicates that the PDCP entity of the DRB needs to be rebuilt, and PDCP re-establishment information is carried only when the DRB's UDC configuration needs to be deleted; 4) UDC configuration information, which includes at least the following information: ① UDC decompression buffer size, an enumeration type, where a value of "yes" includes at least one of the following: 2048 bytes, 4096 bytes, and 8912 bytes; ② Dictionary information, an enumeration type, where a value of "yes" includes at least one of the following: SIP-SID dictionary, custom dictionary; ③ UDC continuity indication information: an enumeration type, where a value of "yes" indicates that the PDCP entity can continue or restart the uplink data compression function during the PDCP reconstruction process.

[0097] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: if, after receiving a first bearer context establishment request message from a first base station control plane entity, the first base station user plane entity finds that the UDC configuration is included in the PDCP configuration carried in the first bearer context modification request message, and the first base station user plane supports UDC configuration, then it configures the uplink data compression function of the corresponding DRB bearer using relevant parameters and returns a first bearer context establishment response message to the first base station control plane entity; if, after receiving a first bearer context modification request message from a first base station control plane entity, the first base station user plane entity finds that the UDC configuration is included in the PDCP configuration carried in the first bearer context modification request message, and the first base station user plane supports UDC configuration, then it configures the uplink data compression function of the corresponding DRB bearer using relevant parameters and returns a first bearer context modification response message to the first base station control plane entity.

[0098] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: The first base station user plane entity performs bearer configuration through the following steps: checking whether the bearer configuration information of each DRB identifier in the list of bearers to be released carries UDC configuration information; if it carries UDC configuration information, then releasing the bearer corresponding to the DRB identifier; checking whether the PDCP configuration information in the bearer configuration information of each bearer in the list of bearers to be modified carries UDC configuration information; if the first base station user plane entity supports UDC capability, then configuring uplink data compression function for the bearer; if the number of configured uplink data compression bearers exceeds the preset UDC bearer upper limit, then determining that the bearer modification has failed, generating a failure reason value, the failure reason value being used to indicate that the number of UDC bearers exceeds the preset UDC bearer upper limit or that the PDCP bearer configuration cannot be supported; if any bearer with configured UDC function... If the configuration information of the bearer carries PDCP re-establishment indication information, then all data, decompression cache, and dictionary information in that bearer are cleared. The dictionary information and decompression cache are reconfigured according to the carried UDC configuration information. Specifically, if no dictionary is configured in the dictionary information, the UDC decompression cache size is set to 0; if a dictionary is configured in the dictionary information, the UDC decompression cache size is configured according to the dictionary information. Check whether the PDCP configuration information in the bearer configuration information of each bearer in the list of requested bearers carries UDC configuration information. If the first base station user plane entity supports UDC capability, then uplink data compression function is configured for that bearer. If the number of configured uplink data compression bearers exceeds the preset UDC bearer limit, then the bearer establishment is determined to have failed, and a failure reason value is generated. The failure reason value is used to indicate that the number of UDC bearers exceeds the preset UDC bearer limit or that the PDCP bearer configuration cannot support it.

[0099] In some embodiments, the first bearer context establishment response message or the first bearer context modification response message includes: a bearer configuration success information list or a bearer configuration failure information list; the bearer configuration success information list is used to indicate one or more data bearers that have been successfully configured in the requested bearer list; the bearer configuration failure information list is used to indicate one or more data bearers that cannot be configured in the requested bearer list.

[0100] In some embodiments, the bearer configuration success information list includes: identifiers of one or more data bearers that have been successfully configured; the bearer configuration failure information list includes: identifiers of one or more data bearers that cannot be configured and the failure reason for each data bearer, including: the number of UDC bearers exceeds the preset UDC bearer limit or the PDCP bearer configuration cannot be supported.

[0101] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: after receiving a first bearer context establishment response message or a first bearer context modification response message from a first base station user plane entity, the first base station control plane entity determines the configuration result of the bearer to be established or modified in the first base station user plane entity; the first base station control plane entity generates a first RRC reconfiguration message to be sent to the terminal based on the configuration result, and sends the established or modified bearer configuration information to the terminal through the first RRC reconfiguration message, wherein the bearer configuration information carried in the first RRC reconfiguration message includes: UDC configuration information, configuration The bearers in the configuration result have a mapping relationship with the bearers in the first RRC reconfiguration message; for bearers that need to be added and configured as UDCs, the DRB identifier of the bearer is placed in the DRB establishment list in the RRC message; for bearers that need to be modified and configured as UDCs, the DRB identifier of the bearer is placed in the DRB release list and DRB establishment list in the RRC message, and it is ensured that the sum of the number of UDC bearers configured by the terminal after RRC reconfiguration and the number of currently active uplink data compression bearers does not exceed the preset UDC bearer limit value, and the number of currently active uplink data compression bearers is the number of uplink data compression bearers that have been activated and not released.

[0102] In some embodiments, the first RRC reconfiguration message includes at least the following information: 1) DRB release list, including one or more DRB identifiers whose UDC configuration information needs to be deleted; 2) DRB creation and modification list, including one or more DRB configuration information, each DRB configuration information including at least the following information: ① DRB identifier; ② UDC decompression cache size, enumeration type, with values ​​including at least one of the following: 2048 bytes, 4096 bytes, and 8912 bytes; ③ Dictionary information: enumeration type, with values ​​including at least one of the following: SIP-SID dictionary, custom dictionary.

[0103] In some embodiments, after the first base station control plane entity sends the successfully established or modified bearer configuration information to the terminal via the first RRC reconfiguration message, the method for maintaining data compression continuity provided in this embodiment further includes the following steps: the terminal performs UDC configuration and reconfiguration through the following steps: for each DRB identifier in the DRB release list, delete all configuration information of the corresponding DRB, and record the number of UDC bearers to be released as T1; for each bearer in the DRB establishment or modification list that needs to be configured with UDC, configure the UDC decompression cache size and dictionary information, set all initial information in the cache to 0, and record the number of UDC bearers to be established. The number of DC bearers is T2; the number of UDC bearers established by the terminal before receiving the first RRC reconfiguration message is T0. When the value of T0-T1+T2 does not exceed the preset UDC bearer limit or no established DRB identifier is added or modified directly without release, the UDC configuration of the bearer is determined to be successful, and the first RRC reconfiguration confirmation message is generated. When the value of T0-T1+T2 exceeds the preset UDC bearer limit or an established DRB identifier is added or modified directly without release, the UDC configuration of the bearer is determined to be unsuccessful, and the first RRC reconfiguration failure message is generated.

[0104] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: a first base station control plane entity determines the small data packet transmission bearer that needs to be suspended when the terminal enters the inactive state, and instructs the first base station user plane entity to trigger the bearer suspension process through a second bearer context modification request message, wherein the second bearer context modification request message contains at least the following information: bearer suspension indication information: enumeration type, the value of which includes at least: bearer suspension, bearer resumption and small data packet transmission resumption.

[0105] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: after receiving the second bearer context modification request message, the first base station user plane entity suspends all bearers according to the suspension indication carried in the bearer suspension indication information. For bearers with configured UDC, the pre-configured decompression cache and dictionary information are maintained during the suspension period, and no clearing or resetting operation is performed on the UDC decompression cache and dictionary. The second bearer context modification response message is generated and sent to the first base station control plane entity.

[0106] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: after receiving the second bearer context modification response message, the first base station control plane entity determines the uplink data compression applicable area of ​​the terminal according to the pre-configuration information, generates a second RRC reconfiguration message to be sent to the terminal, and the second RRC reconfiguration message is used to instruct the terminal to maintain the uplink compression capability of the small data packet transmission bearer when it enters the RRC inactive state.

[0107] In some embodiments, the second RRC reconfiguration message includes: suspended configuration information; the suspended configuration information includes at least the following information: an SDT bearer list, including one or more SDT bearer identifiers, each SDT bearer identifier being an integer value; and uplink data compression continuity indication information, an enumeration type, with a value of cell or radio access network notification area RNA.

[0108] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: After receiving the second RRC reconfiguration message, the terminal configures the relevant bearers according to the following process and sends a second RRC reconfiguration confirmation message back to the first base station: If the second RRC reconfiguration message contains suspended configuration information, it further determines whether the suspended configuration information contains an SDT bearer list; if the suspended configuration information contains an SDT bearer list, it saves the corresponding DRB identifier and determines that the bearer with the corresponding DRB identifier supports the terminal in transmitting small data packets when the RRC is not active; it determines whether the suspended configuration information contains... Uplink data compression continuity indication information; if the suspension configuration information includes uplink data compression continuity indication information, then all bearers that support SDT state and are configured with UDC will maintain the uplink data compression configuration when sending small data packets, continue to maintain the configured decompression cache and dictionary information, and save the configured uplink data compression applicable area; if the suspension configuration information does not include uplink data compression continuity indication information, then all bearers that support SDT state and are configured with UDC will not use uplink data compression to send small data packets when the terminal is inactive, and will clear the configured decompression cache and dictionary information.

[0109] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: if the suspend configuration information does not contain an SDT bearer list, then it is determined that the bearer with the corresponding DRB identifier does not support the transmission of small data packets when the terminal is in RRC non-active state.

[0110] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: when the terminal's SDT carries uplink data packets to be sent, the uplink data packets to be sent are cached in the application layer, and the access layer is instructed to check whether the currently camped cell is within the pre-configured uplink data compression applicable area; if the access layer finds that the currently camped cell is within the pre-configured uplink data compression applicable area, the access layer instructs the application layer to compress the uplink data, sends the uplink data packets cached in the application layer to the terminal's PDCP layer, and according to the pre-configured dictionary information, sends the uplink data packets cached in the application layer to the compression cache to complete data compression, and then sends them to the terminal's MAC layer; when the data volume of the uplink data packets reaches a preset data volume threshold, subsequent transmission operations are triggered; if the access layer finds that the currently camped cell is not within the pre-configured uplink data compression applicable area, the application layer notifies the access layer of the uplink data packets to be sent, and the access layer does not perform uplink data compression operations when sending uplink data packets.

[0111] In some embodiments, the second base station differs from the first base station, and the method further includes: after receiving the RRC connection recovery request message and uplink data packet sent by the terminal, if the second base station finds that there is no user context information of the terminal, it caches the received uplink data packet at the MAC layer of the second base station and sends a user context acquisition request message to the control plane entity of the first base station. The user context acquisition request message contains the cell identifier, downlink channel address and SDT indication information currently in which the terminal is camped.

[0112] In some embodiments, the user context acquisition request message further includes: SDT auxiliary information, which includes: one or more transmissions.

[0113] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: a first base station control plane entity checks whether the cell where the terminal is currently camped is within a pre-configured uplink data compression applicable area; if the first base station control plane entity finds that the cell where the terminal is currently camped is within a pre-configured uplink data compression applicable area, it determines that the UDC transmission bearer should continue to use the existing compression cache and dictionary information for uplink data decompression operation, and returns a partial user context transfer request message to the second base station; if the first base station control plane entity finds that the cell where the terminal is currently camped is not within a pre-configured uplink data compression applicable area, it sends a user context acquisition response message to the second base station.

[0114] In some embodiments, a partial user context transfer request message includes: 1) an identifier assigned to the user by the second base station on the base station interface; 2) an identifier assigned to the user by the first base station on the base station interface; 3) an SDT bearer establishment list, including: one or more SDT bearer lists, each SDT bearer list including: ① a DRB list; ② uplink user plane address information on the inter-base station interface; ③ RLC bearer configuration information of the DRB; ④ QoS information of the DRB; ⑤ RLC mode; ⑥ SN length of the RLC; ⑦ slice configuration information.

[0115] In some embodiments, the user context acquisition response message includes: 1) an identifier assigned to the user by the second base station on the base station interface; 2) an identifier assigned to the user by the first base station on the base station interface; 3) a DRB identifier list, containing one or more DRB configuration information, each DRB configuration information containing the following information: ① logical channel identifier, which is an integer value; ② RLC layer configuration information; ③ MAC layer configuration information; ④ PDCP layer configuration information.

[0116] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: if the second base station receives a partial user context transfer request message, it returns a partial user context transfer response message. The partial user context transfer response message contains an SDT data forwarding DRB identifier list, which includes one or more DRB configuration information. Each DRB configuration information includes the following information: ① DRB identifier; ② UDC indication information, an enumeration type, where a value of "yes" indicates that the DRB is configured as a UDC; ③ Logical channel identifier, which takes the value of an integer; ④ Downlink user plane address information of the inter-base station interface.

[0117] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: After receiving a partial user context transfer request message, the first base station control plane entity sends a third bearer context modification request message to the first base station user plane entity. The third bearer context modification request message is used to request the resumption of data reception. The third bearer context modification request message contains the following information: 1) bearer suspension indication information, an enumeration type, with values ​​including at least: bearer suspension, bearer resumption, and small packet transmission resumption; 2) downlink channel address, including: IP address and port address; 3) UDC continuity indication information: a boolean type, with a value of "yes" indicating that all bearers configured as SDT bearers and configured with UDC have resumed uplink data compression continuity maintenance function.

[0118] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: after receiving a third bearer context modification request message, the first base station user plane entity restores the terminal's small data packet transmission bearer according to the small data packet transmission recovery indication information. When the value of the UDC continuity indication information is yes, it determines whether the bearer recovery of the configured UDC uses pre-configured cache information and dictionary information according to the second bearer configuration information; if not, it clears the pre-configured cache information and dictionary information; the first base station user plane entity allocates address information for receiving uplink data for each bearer.

[0119] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: a first base station user plane entity sends a third bearer context modification response message to a first base station control plane entity to notify the first base station control plane entity that the bearer configuration has been completed.

[0120] In some embodiments, the third bearer context modification response message includes the following information: 1) a list of successfully configured bearers, including the identifiers of one or more SDT bearers; 2) the receive address information of the uplink bearer, including the IP address and port address.

[0121] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: after receiving the third bearer context modification response message, the first base station control plane entity sends the uplink bearer's receive address information to the second base station through the context acquisition response message. When the first base station and the second base station are the same base station, the first base station control plane entity sends the uplink bearer's receive address information to the first base station separation entity.

[0122] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: after receiving a third bearer context modification response message, the second base station sends the cached uplink data to the user plane entity of the first base station according to the receive address information of the uplink bearer.

[0123] In some embodiments, the method for maintaining data compression continuity provided in this disclosure further includes the following steps: the first base station user plane entity completes the decompression operation of uplink data according to the pre-configured cache information and dictionary information, and completes the update operation of the cache information and dictionary information.

[0124] The following two specific embodiments illustrate the user plane configuration method for supporting low-latency services provided in this disclosure:

[0125] Example 1: In a control plane CP / user plane UP separated base station scenario, the gNB-CU-CP modifies the UDC configuration of a bearer through the E1 interface message "Bearer ContextModification procedure". DRB1 already has a UDC configuration. The gNB-CU-CP deletes the UDC configuration of DRB1 and configures UDC capabilities for the newly established bearers DRB2 and DRB3. Subsequently, the gNB-CU-CP updates the corresponding bearer's UDC configuration information for the UE via an RRC reconfiguration message.

[0126] The first base station control plane entity (gNB-CU-CP1) sends the first bearer configuration information to the first base station user plane configuration entity by placing it in the first DRB establishment list through a first bearer establishment request or a Bearer Context Modification Request. The total number of uplink data compression bearers activated and the number of activated uplink data compression bearers minus the number of released uplink data compression bearers configured through the first bearer establishment or modification request message shall not exceed the first configured number. The Bearer Context Modification Request includes the following information:

[0127] ●DRB to Setup List;

[0128] ●DRB to Modify List;

[0129] The information contained in the DRB to Setup List for DRB2 and DRB3 is as follows:

[0130] For DRB2:

[0131] ●DRB sign: 2;

[0132] ●SDT Bearer Type Indicator: Yes;

[0133] ●UDC configuration information includes the following:

[0134] ■ Cache size: 2048 bytes;

[0135] ■ Dictionary information: SIP-DIP;

[0136] For DRB3:

[0137] ●DRB label: 3;

[0138] ●SDT Bearer Type Indicator: Yes;

[0139] ●UDC configuration information includes the following:

[0140] ■ Cache size: 2048 bytes;

[0141] ■ Dictionary information: SIP-DIP;

[0142] The DRB to Modify List includes the following for DRB1:

[0143] ●DRB label: 3;

[0144] ●SDT Bearer Type Indicator: Yes;

[0145] ●PDCP re-establishment information: Yes;

[0146] 1) After receiving the Bearer Context ModificationRequest, the first base station user plane entity (gNB-CU-UP1) processes it in the following order:

[0147] ● Check the list of released bearers; if it is empty, do not perform the operation.

[0148] ● Check the DRB to Modify List. If the DRB1 bearer is configured with a re-establishment instruction and previously configured with UDC information, clear all data in the bearer, as well as the decompression cache and dictionary information.

[0149] ● Check the DRB to Setup List. The PDCP configuration information in both DRB1 and DRB2 carries UDC configuration. If the first base station user plane entity (gNB-CU-UP1) supports UDC capability, then the bearer is configured for uplink data compression. The decompression cache information is configured according to the dictionary information, and a Bearer Context ModificationResponse message is generated.

[0150] 2) The first base station user plane entity (gNB-CU-UP1) generates a Bearer ContextModification Response message based on the UDC configuration. The Bearer Context Modification Response message includes the following:

[0151] ●DRB1;

[0152] ●DRB2;

[0153] ●DRB3;

[0154] 3) After receiving the Bearer Context ModificationResponse message, the first base station control plane entity (gNB-CU-CP1) determines the configuration result carried in the first base station user plane entity (gNB-CU-UP1) and sends the bearer configuration information to the terminal via an RRC reconfiguration message. The RRC reconfiguration message includes the following:

[0155] ●First DRB Release List: DRB1

[0156] ●DRB1 configuration information:

[0157] ■DRB1

[0158] ●DRB2 configuration information:

[0159] ■DRB2

[0160] ■UDC compressed cache size: 2048

[0161] ■ Dictionary Information: SIP-SDP Dictionary

[0162] ●DRB3 configuration information:

[0163] ■DRB3

[0164] ■UDC compressed cache size: 2048

[0165] ■ Dictionary Information: SIP-SDP Dictionary

[0166] Example 2: In a CP / UP separated base station scenario, after the UE enters the RRC inactive state, it moves from the second base station (gNB1) to the second base station (gNB2). The UDC available area configured on the network side is the RNA range, and the second base station (gNB2) belongs to the RNA range. Both DRB1 and DRB2 are configured with UDC continuity.

[0167] 1) The first base station control plane entity (gNB-CU-CP1) triggers the SDT bearer to enter a suspended state and indicates the bearer suspension process through the BearerContext Modification Request message, wherein the Bearer ContextModification Request message includes, but is not limited to, the following:

[0168] ● Carrying suspension indication information: Suspend

[0169] 2) After receiving the Bearer Context ModificationRequest message, the first base station user plane entity (gNB-CU-UP1) suspends all bearers according to the suspension indication carried in the bearer suspension indication information. At the same time, for bearers configured with UDC, their decompressor cache and dictionary configuration information need to be maintained during the suspension period without any clearing or resetting to 0. The first base station user plane entity (gNB-CU-UP1) generates a Bearer Context Modification Response message and sends it to the first base station control plane entity (gNB-CU-CP1).

[0170] 3) After receiving the Bearer Context ModificationResponse message, the first base station control plane entity (gNB-CU-CP1) determines the applicable scope of the terminal's UDC bearer based on the first pre-configuration information and generates a second RRC message to be sent to the terminal to instruct the terminal to maintain the uplink compression capability of the SDT bearer when entering the inactive state. The second RRC message includes, but is not limited to, the following information:

[0171] ●Suspend configuration information, including the following:

[0172] ■SDT Bearer List: DRB1 and DRB2

[0173] ■Uplink data compression continuity indication information: RNA

[0174] 4) After receiving the RRC reconfiguration message, the terminal configures the relevant bearers according to the following process and sends an RRC reconfiguration completion message for these bearers back to the first base station:

[0175] If the suspension configuration information is included, it is further determined whether the SDT bearer list is included. If the SDT bearer list is included, the corresponding DRB identifier is saved and these bearers are determined to support the transmission of small data packets when the terminal is inactive. It is further determined whether the uplink data compression continuity indication information is included. If the uplink data compression continuity indication information is included, all bearers that support the SDT state and are configured with UDC are configured to use uplink compression when sending small data packets, and the dictionary and compression cache are not deleted and are retained, and the UDC applicable scope is saved. Otherwise, these bearers do not support the transmission of small data packets in the idle state.

[0176] 5) When the terminal-side SDT carries data to be sent, the data is buffered at the application layer, and the access layer is instructed to check whether the currently camped cell is within the area range configured by the UDC. Since the second base station (gNB2) is within the area range, the access layer instructs the application layer that the data can be compressed, sends the uplink data packets buffered at the application layer to the terminal's PDCP layer, and sends them to the compression buffer according to the dictionary to complete the data compression before sending them to the terminal's MAC layer. When the data volume reaches the threshold, the subsequent transmission operation is triggered.

[0177] 6) After receiving the connection restoration request message and uplink data packet sent by the terminal, the second base station (gNB2) finds that there is no terminal context information. It then buffers the received uplink data packet and indicates the context acquisition request message to the second base station (gNB1)-CU-CP. The context acquisition request message includes the cell identifier and downlink channel address where the terminal is currently camped.

[0178] 7) When the first base station control plane entity (gNB-CU-CP1) discovers that the cell currently camped by the terminal is within the pre-configured range of the UDC continuity bearer, and determines that the UDC SDT bearer can continue to use the existing cache and dictionary for uplink decompression operations and the anchor point remains at the first base station, it notifies the second base station (gNB2) through a Partial UE Context Transfer request message. The connection response message includes the following:

[0179] ●DRB Identifier List: DRB1 and DRB2, each DRB includes the following information:

[0180] ■Logical channel identifier: Integer value;

[0181] ■RLC layer configuration information;

[0182] ■MAC layer configuration information;

[0183] ■PDCP layer configuration information;

[0184] 8) After receiving the connection recovery failure message, the first base station control plane entity (gNB-CU-CP1) sends a Bearer Context Modification Request message to restore data reception. The Bearer Context Modification Request message includes, but is not limited to, the following information:

[0185] ● Bearer suspension indication information: SDT resumed;

[0186] ●Downlink channel address information: including the IP address and port address for transmission;

[0187] ●UDC continuity indication: Yes;

[0188] 9) After receiving the UDC continuity indication message, the first base station user plane entity (gNB-CU-UP1) restores all SDT bearers of the terminal according to the SDT recovery indication. When the UDC continuity indication is yes, it determines whether the bearer configured with UDC is restored using the existing dictionary and cache information, and determines the receive address information of the uplink bearer.

[0189] 10) The first base station user plane entity (gNB-CU-UP1) notifies the first base station control plane entity (gNB-CU-CP1) that the bearer configuration has been completed via a Bearer Context Modification Response message. The Bearer Context Modification Response message includes, but is not limited to, the following:

[0190] ● Successfully configured bearer list: DRB1 and DRB2;

[0191] ● The receiving address information carried by the uplink.

[0192] 11) After receiving the BearerContext Modification Response message, the first base station control plane entity (gNB-CU-CP1) obtains the response information through the context and sends the uplink transmission address to the second base station (gNB2). If the first base station and the second base station (gNB2) are the same base station, the first base station control plane entity (gNB-CU-CP1) sends the uplink transmission address to the first base station separation entity.

[0193] 12) After receiving the Partial UE ContextTransfer ACK message, the second base station (gNB2) sends the cached uplink data to the user plane entity of the first base station (gNB-CU-UP1) according to the uplink bearer's receive address information.

[0194] 13) The first base station user plane entity (gNB-CU-UP1) completes the decompression operation of uplink data based on the dictionary and cache information, and completes the update operation of the dictionary and cache.

[0195] Figure 7 This illustrates the process of a terminal transitioning from an RRC connected state to an RRC inactive state. Figure 8 This illustrates the process of a terminal transitioning from an RRC inactive state to an RRC connected state.

[0196] Based on the same inventive concept, this disclosure also provides a base station, as described in the following embodiments. Since the principle by which this base station embodiment solves the problem is similar to that of the above method embodiments, the implementation of this base station embodiment can refer to the implementation of the above method embodiments, and repeated details will not be elaborated further.

[0197] Figure 9 This diagram illustrates a base station according to an embodiment of the present disclosure, such as... Figure 9 As shown, the base station 300 includes: a base station control plane entity 3001 and a base station user plane entity 3002;

[0198] Among them, the base station control plane entity 3001 is used to instruct the first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer through the bearer context establishment request or bearer context modification request message. When the terminal enters the RRC inactive state, it instructs the first base station user plane entity 3002 to suspend the UDC bearer and notifies one or more bearer pre-configured UDC applicable areas in the terminal through air interface messages.

[0199] The base station user plane entity 3002 is used to configure or modify the uplink data compression UDC configuration information of the bearer, and to obtain the UDC bearer that needs to be suspended when the terminal enters the RRC inactive state. When the terminal is in the RRC inactive state, the terminal retains the UDC configuration information of the suspended UDC bearer, and when the terminal has a small data packet to send in the pre-configured UDC applicable area on the small data packet SDT bearer, it uses the retained UDC configuration information to perform uplink compression operation on the small data packet to be sent, and sends the compressed small data packet together with the RRC connection recovery request message to the second base station. The second base station is the base station to which the terminal requests the RRC connection recovery. The base station control plane entity is also used to determine that the SDT bearer is in the pre-configured uplink data compression applicable area after receiving the context recovery request message from the second base station, and to instruct the first base station user plane entity on the uplink data compression recovery method. The first base station user plane entity 3002 is also used to decompress the small data packet sent by the terminal based on the retained UDC configuration information.

[0200] Based on the same inventive concept, this disclosure also provides a base station, as described in the following embodiments. Since the principle by which this base station embodiment solves the problem is similar to that of the above method embodiments, the implementation of this base station embodiment can refer to the implementation of the above method embodiments, and repeated details will not be elaborated further.

[0201] Figure 10 This illustration shows a terminal schematic diagram according to an embodiment of the present disclosure, such as... Figure 10 As shown, the terminal 100 includes: an uplink data compression configuration information acquisition module 1001 and an uplink small data packet compression continuity maintenance module 1002.

[0202] The uplink data compression configuration information acquisition module 1001 is used to acquire one or more pre-configured UDC applicable areas of the bearer notified by the first base station control plane entity through air interface messages; the first base station control plane entity instructs the first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer through a bearer context establishment request or bearer context modification request message; the uplink small data packet compression continuity maintenance module 1002 is used to retain the UDC configuration information of the suspended UDC bearer when the terminal is in the RRC inactive state, and to maintain the continuity of the small data packet SDT bearer when the terminal is in the pre-configured UDC applicable area. When a data packet needs to be sent, the reserved UDC configuration information is used to perform uplink compression on the small data packet to be sent. The compressed small data packet is then sent to the second base station along with the RRC connection recovery request message. The second base station is the base station from which the terminal requests the RRC connection recovery. The first base station user plane entity is also used to determine, after receiving the context recovery request message from the second base station, that the SDT bearer is within the pre-configured uplink data compression applicable area, and to instruct the first base station user plane entity on the uplink data compression recovery method, so that the first base station user plane entity decompresses the small data packet sent by the terminal based on the reserved UDC configuration information.

[0203] Based on the same inventive concept, this disclosure also provides a communication system, as described in the following embodiments. Since the principle by which this base station embodiment solves the problem is similar to that of the above method embodiments, the implementation of this base station embodiment can refer to the implementation of the above method embodiments, and repeated details will not be elaborated further.

[0204] Figure 11 A schematic diagram of a communication system according to an embodiment of this disclosure is shown, such as... Figure 11 As shown, the communication system includes: a terminal 100, a first base station 300A on which the terminal 100 is currently camped, and a second base station 300B on which the terminal requests the restoration of the RRC connection;

[0205] The first base station 300A includes a first base station control plane entity 3001A and a first base station user plane entity 3002A. The terminal is used to obtain one or more pre-configured UDC application areas for bearers from the first base station control plane entity 3002A via air interface messages. When the terminal has a small data packet to send within the pre-configured UDC application area on the small data packet SDT bearer, it performs uplink compression on the small data packet to be sent using the reserved UDC configuration information, and sends the compressed small data packet along with an RRC connection recovery request message to the second base station 300B. The second base station 300B is the base station from which the terminal requests RRC connection recovery. The first base station user plane entity 3002A is used to configure or modify the uplink data compression UDC configuration information of the bearer. The first base station control plane entity 3001A uses... The first base station control plane entity 3001A is configured to instruct the first base station user plane entity 3002A to configure or modify the uplink data compression UDC configuration information of the bearer through a bearer context establishment request or bearer context modification request message, and to instruct the first base station user plane entity 3002A to suspend the UDC bearer when the terminal enters the RRC inactive state, and to notify the terminal of the UDC application area of ​​one or more bearers pre-configured through an air interface message; the first base station control plane entity 3001A is also used to determine that the SDT bearer is in the pre-configured uplink data compression application area after receiving the context recovery request message of the second base station 300B, and to instruct the first base station user plane entity 3002A on the uplink data compression recovery method; the first base station user plane entity 3002A is also used to decompress small data packets sent by the terminal based on the retained UDC configuration information.

[0206] Based on the above description of the embodiments, those skilled in the art will readily understand that various aspects of this disclosure can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software aspects. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, terminal device, or network device, etc.) to execute the method according to the embodiments of this disclosure.

[0207] In exemplary embodiments of this disclosure, a computer-readable storage medium is also provided, which may be a readable signal medium or a readable storage medium. Figure 12 This illustration shows a schematic diagram of a computer-readable storage medium according to an embodiment of the present disclosure, such as... Figure 12As shown, the computer-readable storage medium 1200 stores a program product capable of implementing the methods described above. In some possible embodiments, various aspects of this disclosure may also be implemented as a program product comprising program code that, when run on a terminal, causes the terminal to perform the steps described in the "Exemplary Methods" section of this specification according to various exemplary embodiments of this disclosure.

[0208] More specific examples of computer-readable storage media in this disclosure may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0209] In this disclosure, a computer-readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium, capable of transmitting, propagating, or transmitting a program for use by or in connection with an instruction execution system, apparatus, or device.

[0210] Optionally, the program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0211] In practical implementation, program code for performing the operations of this disclosure can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0212] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0213] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0214] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, mobile terminal, or network device, etc.) to execute the methods according to the embodiments of this disclosure.

[0215] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A method for maintaining the continuity of data compression, characterized in that, include: The first base station control plane entity instructs the first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer through a bearer context establishment request or bearer context modification request message. When the terminal enters the radio resource control (RRC) inactive state, it instructs the first base station user plane entity on the UDC bearer that needs to be suspended and notifies the terminal of one or more bearer pre-configured UDC applicable areas through an air interface message. The first base station control plane entity configures the terminal to enter the RRC inactive state and maintains UDC continuity when the terminal enters the RRC inactive state. This is so that when the terminal is in the RRC inactive state, the terminal retains the UDC configuration information carried by the suspended UDC. When there is a small data packet to be sent in the small data packet SDT carried in the pre-configured UDC applicable area, the retained UDC configuration information is used to perform uplink compression operation on the small data packet to be sent. The compressed small data packet is sent to the second base station together with the RRC connection recovery request message. The second base station is the base station from which the terminal requests the RRC connection recovery. After receiving the context recovery request message from the second base station, the first base station control plane entity determines that the SDT bearer is within the pre-configured uplink data compression applicable area, and instructs the first base station user plane entity on the uplink data compression recovery method, so that the first base station user plane entity performs decompression operation on the small data packets sent by the terminal based on the retained UDC configuration information.

2. The method for maintaining data compression continuity according to claim 1, characterized in that, The method further includes: The first base station control plane entity sends the first data bearer DRB list to the first base station user plane entity through the first bearer context establishment request message or the first bearer context modification request message to request the establishment or modification of UDC configuration information contained in the PDCP configuration. Specifically, when the first base station is an LTE air interface, the first DRB establishment list adopts the DRB To SetupList in E-UTRAN mode; when the first base station is an NR air interface, the first DRB list adopts the DRB To Setup List included in the PDU Session Resource ToSetup Modification List in NR mode.

3. The method for maintaining data compression continuity according to claim 2, characterized in that, The sum of the number of uplink data compression bearers to be configured for the base station user plane entity and the number of currently activated uplink data compression bearers shall not exceed the preset UDC bearer limit value. The number of currently activated uplink data compression bearers is the number of uplink data compression bearers that have been activated but not released.

4. The method for maintaining data compression continuity according to claim 3, characterized in that, The first bearer context establishment request message contains a first bearer list to be established, and the first bearer list contains: one or more DRB bearer configuration information; The first bearer context modification request message contains a first bearer list to be established and / or a second bearer list to be modified. The first bearer list contains one or more DRB bearer configuration information, and the second bearer list contains: one or more DRB bearer configuration information, bearers of UDCs to be closed, and bearers of UDCs to be released.

5. The method for maintaining data compression continuity according to claim 3, characterized in that, Each DRB bearer configuration information should include at least the following information: 1) The DRB identifier is an integer value; 2) SDT bearer type indication information, enumerated types, when the value is yes, it indicates that the bearer is an SDT bearer, which supports small data packet compression when the terminal is in RRC inactive state; 3) PDCP configuration information, which includes at least the following information: PDCP Re-establishment Indication Information, an enumeration type. When the value is "Yes", it indicates that the PDCP entity of the DRB needs to be rebuilt. PDCP Re-establishment information is only carried when the UDC configuration of the DRB needs to be deleted. 4) UDC configuration information, which includes at least the following information: ① UDC decompression cache size, enumeration type, with values ​​including at least one of the following: 2048 bytes, 4096 bytes, and 8912 bytes; ② Dictionary information, enumeration type, with values ​​including at least one of the following: SIP-SID dictionary, custom dictionary; ③UDC continuity indication information: an enumeration type. When the value is yes, it indicates that the PDCP entity can continue or restart the uplink data compression function during the PDCP reconstruction process.

6. The method for maintaining data compression continuity according to claim 5, characterized in that, The method further includes: If, after receiving the first bearer context establishment request message from the first base station control plane entity, the first base station user plane entity finds that the UDC configuration is included in the PDCP configuration carried in the first bearer context modification request message, and the first base station user plane supports UDC configuration, then it configures the uplink data compression function of the corresponding DRB bearer using relevant parameters and returns the first bearer context establishment response message to the first base station control plane entity. If, after receiving a first bearer context modification request message from a first base station control plane entity, the first base station user plane entity finds that the UDC configuration is included in the PDCP configuration carried in the first bearer context modification request message, and the first base station user plane supports UDC configuration, then it configures the uplink data compression function of the corresponding DRB bearer using relevant parameters and returns a first bearer context modification response message to the first base station control plane entity.

7. The method for maintaining data compression continuity according to claim 6, characterized in that, The method further includes: The first base station user plane entity performs bearer configuration through the following steps: Check whether the bearer configuration information of each DRB identifier in the list of bearers to be released carries UDC configuration information. If it carries UDC configuration information, release the bearer corresponding to that DRB identifier. Check the list of bearers requested for modification. For each bearer, check if its PDCP configuration information includes UDC configuration information. If the first base station user plane entity supports UDC capability, configure uplink data compression for that bearer. If the number of configured uplink data compression bearers exceeds the preset UDC bearer limit, the bearer modification is determined to have failed, and a failure reason value is generated. This failure reason value indicates that the number of UDC bearers exceeds the preset UDC bearer limit or that the PDCP bearer configuration cannot support it. If any bearer with configured UDC function carries PDCP re-establishment indication information in its configuration information, clear all data, decompression cache, and dictionary information in that bearer. Reconfigure the dictionary information and decompression cache according to the carried UDC configuration information. If no dictionary is configured in the dictionary information, set the UDC decompression cache size to 0. If a dictionary is configured in the dictionary information, configure the UDC decompression cache size according to the dictionary information. Check whether the PDCP configuration information in the bearer configuration information of each bearer in the requested bearer list carries UDC configuration information. If the user plane entity of the first base station supports UDC capability, then configure uplink data compression function for the bearer. If the number of configured uplink data compression bearers exceeds the preset UDC bearer upper limit, then determine that the bearer establishment has failed and generate a failure reason value. The failure reason value is used to indicate that the number of UDC bearers exceeds the preset UDC bearer upper limit or that the PDCP bearer configuration cannot support it.

8. The method for maintaining data compression continuity according to claim 7, characterized in that, The first bearer context establishment response message or the first bearer context modification response message includes: a list of bearer configuration success information or a list of bearer configuration failure information; The bearer configuration success information list is used to indicate one or more data bearers that have been successfully configured in the list of bearers requested to be established or modified; The bearer configuration failure information list is used to indicate one or more data bearers that cannot be configured in the list of bearers requested to be established or modified.

9. The method for maintaining data compression continuity according to claim 8, characterized in that, The bearer configuration success information list includes: Identifiers for one or more successfully configured data bearers; The bearer configuration failure information list includes: the identifier of one or more data bearers that cannot be configured and the failure reason for each data bearer. The failure reasons include: the number of UDC bearers exceeds the preset UDC bearer limit or the PDCP bearer configuration cannot be supported.

10. The method for maintaining data compression continuity according to claim 7, characterized in that, The method further includes: After receiving a first bearer context establishment response message or a first bearer context modification response message from a first base station user plane entity, the first base station control plane entity determines the configuration result of the bearer to be established or modified in the first base station user plane entity. The first base station control plane entity generates a first RRC reconfiguration message to be sent to the terminal based on the configuration result, and sends the established or modified bearer configuration information to the terminal through the first RRC reconfiguration message. The bearer configuration information carried in the first RRC reconfiguration message includes: UDC configuration information. The bearer in the configuration result has a mapping relationship with the bearer in the first RRC reconfiguration message. For bearers that need to be added and configured as UDC, the DRB identifier of the bearer is placed in the DRB establishment list in the RRC message; For a bearer that needs to be modified and configured as a UDC, the DRB identifier of the bearer is placed in the DRB release list and DRB creation list in the RRC message. It is ensured that the sum of the number of bearers configured as UDC by the terminal after RRC reconfiguration and the number of currently active uplink data compression bearers does not exceed the preset UDC bearer limit value. The number of currently active uplink data compression bearers is the number of uplink data compression bearers that have been activated and not released.

11. The method for maintaining data compression continuity according to claim 10, characterized in that, The first RRC reconfiguration message contains at least the following information: 1) DRB release list, including: one or more DRB identifiers whose UDC configuration information needs to be deleted; 2) DRB creation and modification list, including: one or more DRB configuration information, each DRB configuration information containing at least the following information: ①DRB signage; ② UDC decompression cache size, enumeration type, with values ​​including at least one of the following: 2048 bytes, 4096 bytes, and 8912 bytes; ③ Dictionary information: an enumeration type, with values ​​including at least one of the following: SIP-SID dictionary, custom dictionary.

12. The method for maintaining data compression continuity according to claim 10, characterized in that, After the first base station control plane entity sends the successfully established or modified bearer configuration information to the terminal via the first RRC reconfiguration message, the method further includes: The terminal performs UDC configuration and reconfiguration through the following steps: For each DRB identifier in the DRB release list, delete all configuration information of the corresponding DRB, and record the number of UDC bearers to be released as T1; For each UDC bearer that needs to be configured in the DRB creation or modification list, configure the UDC decompression cache size and dictionary information, set all the initial information in the cache to 0, and record the number of UDC bearers that need to be created as T2. The number of UDC bearers established by the terminal before receiving the first RRC reconfiguration message is recorded as T0. If the value of T0-T1+T2 does not exceed the preset UDC bearer limit or no established DRB identifier is added or modified directly without being released, the UDC configuration of the bearer is determined to be successful, and the first RRC reconfiguration confirmation message is generated. If the value of T0-T1+T2 exceeds the preset UDC bearer limit or an established DRB identifier is added or modified directly without being released, the UDC configuration of the bearer is determined to be failed, and the first RRC reconfiguration failure message is generated.

13. The method for maintaining data compression continuity according to claim 1, characterized in that, The method further includes: The first base station control plane entity determines the small data packet transmission bearer that needs to be suspended when the terminal enters the inactive state, and instructs the first base station user plane entity to trigger the bearer suspension process through a second bearer context modification request message. The second bearer context modification request message contains at least the following information: Bearer suspension indication information: an enumeration type, with values ​​including at least: bearer suspension, bearer resumption, and small packet transmission resumption.

14. The method for maintaining data compression continuity according to claim 13, characterized in that, The method further includes: After receiving the second bearer context modification request message, the first base station user plane entity suspends all bearers according to the suspension indication carried in the bearer suspension indication information. For bearers with configured UDC, the pre-configured decompression cache and dictionary information are maintained during the suspension period. No clearing or resetting of the UDC decompression cache and dictionary is performed. The second bearer context modification response message is generated and sent to the first base station control plane entity.

15. The method for maintaining data compression continuity according to claim 14, characterized in that, The method further includes: After receiving the second bearer context modification response message, the first base station control plane entity determines the uplink data compression applicable area of ​​the terminal based on the pre-configuration information, and generates a second RRC reconfiguration message to be sent to the terminal. The second RRC reconfiguration message is used to instruct the terminal to maintain the uplink compression capability of the small data packet transmission bearer when it enters the RRC inactive state.

16. The method for maintaining data compression continuity according to claim 15, characterized in that, The second RRC reconfiguration message includes: suspended configuration information; The suspension configuration information includes at least the following information: The SDT bearer list includes one or more SDT bearer identifiers, each of which is an integer value. Uplink data compression continuity indication information, enumerated type, value is cell or radio access network notification area RNA.

17. The method for maintaining data compression continuity according to claim 15, characterized in that, The method further includes: After receiving the second RRC reconfiguration message, the terminal configures the relevant bearer according to the following procedure and sends a second RRC reconfiguration confirmation message back to the first base station: If the second RRC reconfiguration message contains suspended configuration information, then it is further determined whether the suspended configuration information contains the SDT bearer list; If the suspend configuration information contains an SDT bearer list, then the corresponding DRB identifier is saved, and the bearer of the corresponding DRB identifier is determined to support the transmission of small data packets by the terminal in the RRC non-active state. Determine whether the suspend configuration information contains uplink data compression continuity indication information; If the suspend configuration information includes uplink data compression continuity indication information, then all bearers that support SDT state and are configured with UDC will maintain the uplink data compression configuration when sending small data packets, continue to maintain the configured decompression cache and dictionary information, and save the configured uplink data compression applicable area. If the suspend configuration information does not include uplink data compression continuity indication information, then all bearers that support SDT state and are configured with UDC will not use uplink data compression to send small data packets when the terminal is inactive, and will clear the configured decompression cache and dictionary information.

18. The method for maintaining data compression continuity according to claim 17, characterized in that, The method further includes: If the suspend configuration information does not contain the SDT bearer list, it is determined that the bearer with the corresponding DRB identifier does not support the transmission of small data packets when the terminal is in the RRC non-active state.

19. The method for maintaining data compression continuity according to claim 1, characterized in that, The method further includes: When the terminal's SDT carries uplink data packets to be sent, it buffers the uplink data packets to be sent at the application layer and instructs the access layer to check whether the currently camped cell is within the pre-configured uplink data compression applicable area. If the access layer finds that the currently camped cell is within the pre-configured uplink data compression applicable area, the access layer instructs the application layer to compress the uplink data, sends the uplink data packets cached by the application layer to the terminal's PDCP layer, and sends the uplink data packets cached by the application layer to the compression buffer according to the pre-configured dictionary information to complete the data compression before sending them to the terminal's MAC layer. When the data volume of the uplink data packet reaches the preset data volume threshold, the subsequent transmission operation is triggered. If the access layer finds that the currently camped cell is not within the pre-configured uplink data compression applicable area, the application layer will notify the access layer of the uplink data packets to be sent, and the access layer will not perform uplink data compression operation when sending uplink data packets.

20. The method for maintaining data compression continuity according to claim 1, characterized in that, The second base station differs from the first base station, and the method further includes: After receiving the RRC connection recovery request message and uplink data packet sent by the terminal, if the second base station finds that there is no user context information of the terminal, it caches the received uplink data packet at the MAC layer of the second base station and sends a user context acquisition request message to the control plane entity of the first base station. The user context acquisition request message contains the cell identifier, downlink channel address and SDT indication information of the terminal currently camped.

21. The method for maintaining data compression continuity according to claim 20, characterized in that, The user context acquisition request message also includes: SDT auxiliary information, which includes: one or more transmissions.

22. The method for maintaining data compression continuity according to claim 20, characterized in that, The method further includes: The first base station control plane entity checks whether the cell where the terminal is currently camped is within the pre-configured uplink data compression applicable area; If the first base station control plane entity discovers that the cell where the terminal is currently camped is located within the pre-configured uplink data compression applicable area, it determines that the UDC transmission bearer will continue to use the existing compression buffer and dictionary information to perform uplink data decompression operations, and returns a partial user context transfer request message to the second base station. If the first base station control plane entity discovers that the cell where the terminal is currently camped is not within the pre-configured uplink data compression applicable area, it sends a user context acquisition response message to the second base station.

23. The method for maintaining data compression continuity according to claim 22, characterized in that, The partial user context transfer request message includes: 1) The identifier assigned to the user by the second base station on the base station interface; 2) The first base station assigns an identifier to the user on its base station interface; 3) SDT bearer establishment list, including: one or more SDT bearer lists, each SDT bearer list including: ①DRB list; ②Uplink user plane address information on the inter-base station interface; ③ RLC bearer configuration information of DRB; ④ DRB QoS information; ⑤ RLC mode; ⑥ The SN length of RLC; ⑦ Slice configuration information.

24. The method for maintaining data compression continuity according to claim 22, characterized in that, The user context retrieval response message includes: 1) The identifier assigned to the user by the second base station on the base station interface; 2) The first base station assigns an identifier to the user on its base station interface; 3) DRB identifier list, containing one or more DRB configuration information, each DRB configuration information containing the following information: ① Logical channel identifier, which is an integer value; ② RLC layer configuration information; ③MAC layer configuration information; ④PDCP layer configuration information.

25. The method for maintaining data compression continuity according to claim 22, characterized in that, The method further includes: If the second base station receives a partial user context transfer request message, it returns a partial user context transfer response message. This partial user context transfer response message contains a list of SDT data forwarding DRB identifiers. The list of SDT data forwarding DRB identifiers includes one or more DRB configuration information entries, each containing the following information: ①DRB signage; ②UDC indication information, an enumeration type. When the value is "yes", it indicates that the DRB is configured as UDC. ③ Logical channel identifier, which takes the value of an integer. ④ Downlink user plane address information of the inter-base station interface.

26. The method for maintaining data compression continuity according to claim 22, characterized in that, The method further includes: After receiving a partial user context transfer request message, the first base station control plane entity sends a third bearer context modification request message to the first base station user plane entity. The third bearer context modification request message is used to request the resumption of data reception, and the third bearer context modification request message contains the following information: 1) Bearer suspension indication information, enumeration type, with values ​​including at least: bearer suspension, bearer resumption, and small packet transmission resumption; 2) Downlink channel address, including: IP address and port address; 3) UDC continuity indication information: Boolean type. When the value is yes, it means that all bearers configured as SDT bearers and configured with UDC have resumed uplink data compression continuity maintenance function.

27. The method for maintaining data compression continuity according to claim 26, characterized in that, The method further includes: After receiving the third bearer context modification request message, the first base station user plane entity restores the terminal's small data packet transmission bearer according to the small data packet transmission recovery indication information. When the value of the UDC continuity indication information is yes, it determines whether the bearer recovery of the configured UDC should use the pre-configured cache information and dictionary information according to the second bearer configuration information; if not, it clears the pre-configured cache information and dictionary information. The first base station user plane entity assigns address information for receiving uplink data to each bearer.

28. The method for maintaining data compression continuity according to claim 27, characterized in that, The method further includes: The first base station user plane entity sends a third bearer context modification response message to the first base station control plane entity to notify the first base station control plane entity that the bearer configuration has been completed.

29. The method for maintaining data compression continuity according to claim 28, characterized in that, The third bearer context modification response message contains the following information: 1) A list of successfully configured bearers, including identifiers of one or more SDT bearers; 2) The receiving address information carried by the uplink includes: IP address and port address.

30. The method for maintaining data compression continuity according to claim 29, characterized in that, The method further includes: After receiving the third bearer context modification response message, the first base station control plane entity sends the uplink bearer's receive address information to the second base station through the context acquisition response message. When the first base station and the second base station are the same base station, the first base station control plane entity sends the uplink bearer's receive address information to the first base station separation entity.

31. The method for maintaining data compression continuity according to claim 30, characterized in that, The method further includes: After receiving the third bearer context modification response message, the second base station sends the cached uplink data to the user plane entity of the first base station according to the receive address information of the uplink bearer.

32. The method for maintaining data compression continuity according to claim 31, characterized in that, The method further includes: The first base station user plane entity completes the uplink data decompression operation based on the pre-configured cache information and dictionary information, and completes the cache information and dictionary information update operation.

33. A base station, characterized in that, include: Base station control plane entities and base station user plane entities; The base station control plane entity is used to instruct the first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer through a bearer context establishment request or bearer context modification request message. When the terminal enters the RRC inactive state, it instructs the first base station user plane entity to suspend the UDC bearer and notifies one or more bearer pre-configured UDC applicable areas in the terminal through an air interface message. The base station user plane entity is used to configure or modify the uplink data compression UDC configuration information of the bearer, and when the terminal enters the RRC inactive state, it obtains the UDC bearer that needs to be suspended; when the terminal is in the RRC inactive state, the terminal retains the UDC configuration information of the suspended UDC bearer, and when the terminal has a small data packet to send in the small data packet SDT bearer in the pre-configured UDC applicable area, it uses the retained UDC configuration information to perform uplink compression operation on the small data packet to be sent, and sends the compressed small data packet together with the RRC connection recovery request message to the second base station, which is the base station from which the terminal requests the RRC connection recovery; The base station control plane entity is also used to determine, after receiving the context recovery request message from the second base station, that the SDT bearer is within the pre-configured uplink data compression applicable area, and to instruct the first base station user plane entity on the recovery method of uplink data compression; the first base station user plane entity is also used to decompress small data packets sent by the terminal based on the retained UDC configuration information.

34. A terminal, characterized in that, include: Uplink data compression configuration information acquisition module and uplink small data packet compression continuity maintenance module; The uplink data compression configuration information acquisition module is used to acquire one or more pre-configured UDC application areas of the bearer notified by the first base station control plane entity through air interface messages; the first base station control plane entity instructs the first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer through a bearer context establishment request or bearer context modification request message. The uplink small data packet compression continuity maintenance module is used to retain the UDC configuration information of the suspended UDC when the terminal is in the RRC inactive state. When the terminal has a small data packet to send in the small data packet SDT within the pre-configured UDC applicable area, it uses the retained UDC configuration information to perform uplink compression operation on the small data packet to be sent, and sends the compressed small data packet together with the RRC connection recovery request message to the second base station. The second base station is the base station from which the terminal requests the RRC connection recovery. The first base station user plane entity is further configured to, upon receiving the context recovery request message from the second base station, determine that the SDT bearer is within the pre-configured uplink data compression applicable area, instruct the first base station user plane entity on the uplink data compression recovery method, and enable the first base station user plane entity to decompress the small data packets sent by the terminal based on the retained UDC configuration information.

35. A communication system, characterized in that, include: The terminal and the first base station where the terminal is currently camped, and the second base station to which the terminal requests the restoration of the RRC connection; The first base station includes: a first base station control plane entity and a first base station user plane entity; The terminal is used to obtain one or more pre-configured UDC applicable areas from the first base station control plane entity notification via air interface messages, and when the terminal has a small data packet to be sent in the pre-configured UDC applicable area, it uses the reserved UDC configuration information to perform uplink compression operation on the small data packet to be sent, and sends the compressed small data packet together with the RRC connection recovery request message to the second base station, which is the base station from which the terminal requests the RRC connection recovery. The first base station user plane entity is used to configure or modify the uplink data compression UDC configuration information carried. The first base station control plane entity is used to instruct the first base station user plane entity to configure or modify the uplink data compression UDC configuration information of the bearer through a bearer context establishment request or bearer context modification request message, and to instruct the first base station user plane entity to suspend the UDC bearer when the terminal enters the RRC inactive state, and to notify one or more bearer pre-configured UDC applicable areas in the terminal through an air interface message. The first base station control plane entity is further configured to, upon receiving the context recovery request message from the second base station, determine that the SDT bearer is within the pre-configured uplink data compression applicable area, and instruct the first base station user plane entity on the recovery method of uplink data compression; the first base station user plane entity is further configured to perform decompression operation on small data packets sent by the terminal based on the retained UDC configuration information.

36. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for maintaining data compression continuity as described in any one of claims 1 to 32.

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