Uplink Data Plane Management for Quality of Service Data Transmission

Abstract

Embodiments of an apparatus and method for uplink data plane management are disclosed. In one example, a method for handover continuity may include buffering data packets at a user equipment based on a triggering event. The data packets may be mapped to a first quality of service flow and associated with a first radio resource at a source network node. The method may further include identifying a second quality of service flow associated with a second radio resource at a target network node. The method may further include remapping from the first quality of service flow to the second quality of service flow. The method may further include sending the buffered data packets from the user equipment to the target network node based on the remapping.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 006,418, filed on April 7, 2020, entitled "5G HANDOVER UE UPLINK DATA PLANE MANAGEMENT SCHEME FOR LOSSLESS QOS DATA TRANSFER", the entire content of which is incorporated herein by reference. Background Art

[0003] Embodiments of the present disclosure relate to apparatuses and methods for wireless communication.

[0004] Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, and broadcasting. In wireless communication, there may be a transfer of a wireless device from one access node to another. For example, a wireless device running one or more applications may switch from a source access node to a target access node. The terms "handover" and "handoff" and their various forms may be used interchangeably to refer to such a transfer. Summary of the Invention

[0005] Embodiments of apparatuses and methods for uplink data plane management are disclosed herein.

[0006] In one example, a method for handover continuity may include caching data packets at a user equipment based on a trigger event. The data packets may be mapped to a first quality - of - service flow and associated with a first radio resource at a source network node. The method may further include identifying a second quality - of - service flow associated with a second radio resource at a target network node. The method may further include remapping from the first quality - of - service flow to the second quality - of - service flow. The method may further include sending the cached data packets from the user equipment to the target network node based on the remapping.

[0007] In another example, a device (e.g., a user equipment) for switching continuity may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code may be configured to, by means of the at least one processor, cause the device to cache data packets at the user equipment at least based on a triggering event. The data packets may be mapped to a first quality of service flow and associated with a first radio resource at a source network node. The at least one memory and the computer program code may also be configured to, by means of the at least one processor, cause the device to at least identify a second quality of service flow associated with a second radio resource at a target network node. The at least one memory and the computer program code may be further configured to, by means of the at least one processor, cause the device to at least remap from the first quality of service flow to the second quality of service flow. The at least one memory and the computer program code may also be configured to, by means of the at least one processor, cause the device to at least send the cached data packets from the user equipment to the target network node based on the remapping.

[0008] In yet another example, a non-volatile computer-readable medium encoded with instructions, when executed in the hardware of a user equipment, causes the user equipment to perform a process for switching continuity. The process may include caching data packets at the user equipment based on a triggering event. The data packets may be mapped to a first quality of service flow and associated with a first radio resource at a source network node. The process may also include identifying a second quality of service flow associated with a second radio resource at a target network node. The process may also include remapping from the first quality of service flow to the second quality of service flow. The process may also include sending the cached data packets from the user equipment to the target network node based on the remapping. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings incorporated herein and forming a part of the specification illustrate embodiments of the present disclosure and, together with the specification, further serve to explain the principles of the present disclosure and enable a person skilled in the relevant art to implement and use the present disclosure.

[0010] Figure 1 Shows an overview of a 5G base station and network connection in which some embodiments of the present disclosure may be implemented.

[0011] Figure 2 Shows a method according to some embodiments of the present disclosure.

[0012] Figure 3 Shows an uplink data plane management method for lossless quality of service (QoS) data transmission according to some embodiments of the present disclosure.

[0013] Figure 4 Further description of the uplink data plane management method according to some embodiments of the present disclosure is provided.

[0014] Figure 5 A flowchart of some embodiments of the present disclosure is shown.

[0015] Figure 6 A block diagram of a device including a baseband chip, a radio frequency chip, and a host chip according to some embodiments of the present disclosure is shown.

[0016] Figure 7 An example node in which some aspects of the present disclosure can be implemented according to some embodiments of the present disclosure is shown.

[0017] Figure 8 An example wireless network in which some aspects of the present disclosure can be implemented according to some embodiments of the present disclosure is shown.

[0018] Embodiments of the present disclosure will be described below with reference to the accompanying drawings. Detailed Description of the Invention

[0019] Although specific configurations and arrangements are discussed, it should be understood that these discussions are for illustrative purposes only. Those skilled in the relevant art will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the present disclosure. It will be apparent to those skilled in the relevant art that the present disclosure can also be used in various other applications.

[0020] It should be noted that the phrases "an embodiment", "embodiment", "example embodiment", "some embodiments", "certain embodiments", etc. mentioned in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but not necessarily every embodiment includes such specific features, structures, or characteristics. In addition, these phrases do not necessarily refer to the same embodiment. Further, when a specific feature, structure, or characteristic is described as being related to an embodiment, those skilled in the relevant art can implement such feature, structure, or characteristic in combination with other embodiments whether or not it is explicitly described.

[0021] Generally speaking, terms can be understood at least in part from their use in the context. For example, the term "one or more" used herein can be used to describe any feature, structure, or characteristic in a singular sense or can be used to describe a combination of features, structures, or characteristics in a plural sense, at least in part depending on the context. Similarly, the terms "a", "an", or "the" can also be understood to express singular usage or plural usage, at least in part depending on the context. In addition, the term "based on" can also be understood, at least in part depending on the context, not necessarily to express a set of exclusive factors, but to allow the existence of additional factors that are not necessarily explicitly described.

[0022] Aspects of a wireless communication system will now be described with reference to various apparatuses and methods. These apparatuses and methods will be described in detail below and illustrated in the accompanying drawings by various blocks, modules, units, components, circuits, steps, operations, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using electronic hardware, firmware, computer software, or any combination thereof. Whether these elements are implemented as hardware, firmware, or software depends on the particular application and the design constraints imposed on the overall system.

[0023] The techniques described in this disclosure can be used in various wireless communication networks, such as code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and other networks. The terms "network" and "system" are often used interchangeably. CDMA networks can implement radio access technologies (RATs), such as Universal Terrestrial Radio Access (UTRA) and CDMA 2000, etc. TDMA networks can implement RATs, such as Global System for Mobile Communications (GSM). OFDMA networks can implement RATs, such as Long Term Evolution (LTE) or New Radio (NR). The techniques and systems described in this disclosure can be used in the wireless networks and RATs mentioned above, as well as other wireless networks and RATs.

[0024] In a fifth generation (5G) cellular wireless modem, a user equipment (UE) can be connected to a network including various network nodes, including radio access nodes, such as a base station (BS) or a next generation node B (gNB). When the user equipment moves or for other reasons, the user equipment can switch from being connected to a source BS or gNB to being connected to a target BS or gNB through a process called handover. The user equipment can also be connected or switched to a fourth generation (4G) base station. Various access nodes of a 5G radio access network (RAN) can be connected to a user plane function (UPF), which bears the data plane connection for a protocol data unit (PDU) session.

[0025] The user equipment may move in the network and / or the wireless network conditions may change, for example, due to the presence of additional devices or other factors in the area. Therefore, the user equipment can perform measurements periodically or irregularly and may trigger handover conditions on the network (NW). The access and mobility management function (AMF) in the network can trigger handover processing at the source and target BSs or other access nodes.

[0026] If a handover occurs between 5G base stations, the unsent downlink (DL) data can be cached at the source BS and forwarded to the target BS. Once the handover is successfully completed, this cached DL data can be sent to the UE to ensure the continuity of DL data.

[0027] Figure 1 Based on the 3rd Generation Partnership Project (3GPP) Technical Specification (TS) 38.300, version 15 of which is incorporated herein by reference. Figure 1 Shows an overview of a 5G base station and network connection in which some embodiments of the present disclosure can be implemented. As described below, although 5G networks are use case examples for certain embodiments, various embodiments can be applied to heterogeneous networks and non-3GPP networks.

[0028] Figure 1 Shows that a user equipment 110 can be connected to a gNB 120, the gNB 120 can be connected to 5G Core (5GC) network elements (such as AMF and UPF 130) through an interface labeled NG, and connected to other access nodes in the Next Generation Radio Access Network (NG-RAN) through an interface labeled Xn, such as multiple other gNBs or Next Generation Enhanced Node B (ng-eNB). These interfaces can be local interfaces or remote interfaces. For example, two gNBs may be co-located in a single rack-mounted system, and the Xn interface between them may be implemented through a backplane. Alternatively, two gNBs can be located in different locations, and the Xn interface between them can be implemented through a microwave link, an optical fiber link, etc.

[0029] In the NG-RAN, a gNB or ng-eNB can be responsible for inter-cell radio resource management (RRM), radio bearer (RB) control, connection mobility control, radio access control, measurement configuration and provision, and dynamic resource allocation (also known as scheduling).

[0030] In contrast, in the 5GC network, the AMF can be responsible for network access layer (NAS) security and idle state mobility handling. The Session Management Function (SMF) (not explicitly shown in Figure 1 but can be co-located with the AMF and UPF) can be responsible for user equipment Internet Protocol (IP) address allocation and PDU session control. The UPF can be responsible for mobility anchoring and PDU processing. The UPF can also be connected to the Internet or other data networks (not shown).

[0031] The above describes downlink (DL) data processing. Generally, if the same set of radio bearers is configured at the target base station as at the source base station, then the target resumes uplink (UL) handover data for the corresponding radio bearer.

[0032] If the target RB is different from the source BS, then generally there is no direct UL QoS flow data transmission from the source Quality of Service (QoS) flow to the target QoS flow.

[0033] In this case, the Packet Data Convergence Protocol (PDCP) layer at the user equipment can be re-established, and all source data (i.e., data being transmitted to the source node) can be refreshed. Otherwise, for a lossless handover, unacknowledged and unsent data from all QoS flows may queue up to be sent to the target BS on default RBs.

[0034] One challenge faced by 5G UL handover of the UE is how to ensure lossless and seamless handover of UL packets from the source base station to the target BS and distinguish QoS flow priorities. In past methods, if the target BS reconfigures the UE's resources with completely different RBs, UL data from the source BS may be lost during the handover to the target BS. In addition, in the case where the mapping of QoS to Data Radio Bearer (DRB) at the target base station does not match the configuration of the source base station, disordered data may be transmitted to the target base station. Also, when switching from the source base station to the target base station, the differentiated service of UL QoS flows may be lost. Additionally, during the handover process, UL low-latency packet transmission may fail and experience high latency. Moreover, high-throughput continuous data transmission may lose data continuity. Furthermore, there may be invalid user equipment handover UL data transmission, resulting in increased UE PDCP layer reconstruction and setup as well as UE power consumption.

[0035] Some embodiments of the present disclosure provide a 5G UL method at the user equipment for optimizing uplink handover data transmission from a source base station to a target base station with multiple QoS flows. When switching from 5G to 4G, or even to a non-3GPP base station carrying QoS flows, some embodiments of the method can ensure lossless and seamless uplink data continuity. Lossless and seamless uplink data continuity can be beneficial for ultra-reliable low-latency communication (URLLC) as well as high-throughput applications.

[0036] Some embodiments impose flow control on incoming uplink data sources, cache all current QoS flow data, reconfigure the target resources, and remap the cached QoS flow data to new target QoS-DRB resources. Once the handover execution is complete, the cached data can be sent out, and flow control on the incoming UL data sources can be lifted for the corresponding QoS flows.

[0037] Figure 2 A method according to some embodiments of the present disclosure is shown. Figure 2 An overview of some principles and aspects of specific embodiments can be provided, and these principles and aspects will be described in more detail below.

[0038] As Figure 2As shown, the method may include, at 210, a triggering event occurring. The triggering event may be a handover trigger. In other words, the user equipment or other device may detect the occurrence of the triggering event and may thus cause the user equipment to attempt and / or perform a handover. The handover may be referred to as from a source node to a target node, for example, from a source base station or a source access point such as a BS or a gNB to a target base station or a target access point. From the perspective of the user equipment, the triggering event may be the receipt of a radio resource reconfiguration message that may instruct the user equipment to hand over from a source access node to a target access node.

[0039] After the handover trigger at 210, at 220, the user equipment may buffer and store data packets for all QoS flows. The buffering and storing of data packets may be performed using data packets associated with the corresponding quality of service flow identifiers. At 225, the user equipment may also perform flow control on all incoming data packets. The flow control may be implemented on a per-QoS flow basis. Applying the flow control may involve sending a flow control ON message from the baseband chip of the user equipment to the applications and / or host of the user equipment.

[0040] As the handover proceeds, the user equipment may identify new QoS flows and associated radio bearers and cell configurations at 230. The new QoS may be provided by the target node. For example, as part of the handover process, the target node may indicate the QoS flows available or to be available to the user equipment.

[0041] Identifying a second QoS flow associated with a second radio resource at the target network node may include mapping the data radio bearer at the target node to a second QoS flow that matches or approximates the first QoS flow. The data radio bearer may be the same as or different from the data radio bearer at the source node.

[0042] At 240, the user equipment may remap the QoS flows used at the source node to the QoS at the target node. Along with the remapping of the QoS flows, the user equipment may also remap the corresponding radio bearers, cell configurations, and any other necessary or desired parameters. The current QoS flows, i.e., the QoS flows of the source node, may be made to match the QoS flows of the target node as closely as possible.

[0043] At 250, the handover may be considered complete. At this time, the user equipment may synchronize with the target node. Thus, at 260, the user equipment may resume the transmission of the data buffered and / or stored at 220. In addition, once the data buffer level drops below a threshold, the user equipment may resume the IP flow data for a given QoS flow. Until at 265, the flow control is lifted, the user equipment may continue the QoS for each QoS flow to manage the buffered data and any new incoming UL data. The lifting of the flow control at 265 may be based on determining that the data buffer level is at or below a threshold (not shown).

[0044] Some embodiments of the present disclosure, by way of example, relate to caching and suspending all QoS flows during a handover. After a handover is triggered, packets of all QoS flows can be cached and stored. The handover trigger event is shown at 210 in Figure 2 , where the caching and storing of the packets is shown at 220 in Figure 2 . As shown at 225 in Figure 2 , flow control can be applied to the incoming packet source.

[0045] In another example, some embodiments of the present disclosure relate to remapping source data to a new target QoS flow and radio bearer. This remapping is shown at 240 in Figure 2 . Using the new target QoS flow (which can be identified at 230 in Figure 2 ) and the corresponding radio bearer and cell configuration, the current QoS flow can be remapped to the new resource set directly or through a close match.

[0046] In yet another example, some embodiments of the present disclosure relate to resuming data traffic at the target base station with QoS priority. Once the handover is complete and the user equipment is synchronized to the new target base station, the cached data can be resumed at the new base station with QoS priority. Figure 2 The completion of the handover is shown at 250 in Figure 2 , and the resumption of the transmission is shown at 260 in Figure 2 . In some embodiments, flow control can be provided at the uplink data source on a per-QoS flow basis, and the IP flow data of the QoS flow can be resumed after the data cache level drops below a threshold.

[0047] Figure 3 shows an uplink data plane management method for lossless QoS data transmission according to some embodiments of the present disclosure. As shown in Figure 3 , the user equipment 110 (which can be the same as the user equipment 110 in Figure 1 ) can initially be connected to the source base station 120 (which can be the gnB 120 in Figure 1 ), and a handover to the target base station 310 (which can be any gNB or ng-eNB shown in Figure 1 ) can be triggered. In this example, both base stations 120 and 310 are served by a common UPF or gateway 130 (which can be the same AMF / UPF shown in Figure 1 ).

[0048] Thus, the user equipment 110 can be connected to the source base station 120 in the network, the source base station 120 is connected to the target base station 310, and both base stations 120 and 310 can be connected to a common 5G UPF 130. The interfaces between base stations 120 and 310 and the UPF 130 can be as Figure 1 shown. In an alternative, the source base station 120 and the target base station 310 can also be connected through a non-5G network user plane gateway ( Figure 3 the UPF / gateway 130 in), where the user equipment 110 can be connected to the final end-to-end connection through multiple PDU sessions, hosting applications with different quality of service differentiated services. One such configuration can be if the source base station 120 is switching to a 4G, 3G, 2G or non-3GPP network, the data connection can be enabled through a common data server gateway.

[0049] On the baseband chip of the user equipment 110, the incoming PDU data can first be mapped to a QoS flow through the mapping of IP flow to QoS flow, and this mapping can be configured through NAS traffic filtering rules for each PDU session setting. IP header tuple information (e.g., source IP address, destination IP address, source IP port, destination IP port, IP service type, etc.) can be filtered through a set of rules that determine the QoS flow identifier (QFI) for each IP flow. Multiple IP flows can be mapped to one QoS flow.

[0050] Once the QoS flow is determined, a QoS-to-DRB flow mapping table can be used to look up the appropriate DRB for the QoS flow. The QoS-to-DRB flow mapping table can be configured through service data adaptation protocol (SDAP) configuration during the initial radio resource control (RRC) connection establishment and reconfiguration of the user equipment. Each DRB can include one or more QoS flows, each with a different QoS profile. The DRB can be served through the corresponding logical channel (LC), and this logical channel can be scheduled through the media access control (MAC) uplink logical channel priority (LCP) scheduling mechanism for transmission on the uplink, giving priority to low-latency, high-priority QoS flows in higher-priority DRBs.

[0051] In Figure 3 , three applications Appl, App2, and App3 are shown as having corresponding PDU sessions, PDU1, PDU2, and PDU3. In this example, and for illustration only, App1 and App3 are shown as being mapped to three QoS flows, while App2 is shown as being mapped to two QoS flows.

[0052] As an example, when the target base station 310 has a stronger measurement value than the source base station 120, a handover can be triggered according to the handover criteria at the network. The source base station 120 can communicate with the target base station 310 to forward the UE baseband context information of the source base station, as well as the DL cached data of the UE. The source base station 120 can trigger an RRC reconfiguration message to the user equipment 110 to start performing the handover.

[0053] According to some embodiments of the present disclosure, upon receiving the RRC reconfiguration message, UE UL handover data plane management can be initiated. First, the baseband chip of the user equipment 110 can hang up each incoming data source from the application processor (AP) / host chip, and can cache all the unacknowledged and unsent QoS data in each QoS flow. The user equipment 110 can then reconfigure the target resources according to the received information, including QoS flows, radio bearers, mapping of QoS to DRB, cell configuration, and target cell Id and access information. Next, the user equipment 110 can forward the cached data from the source QoS flow to the target QoS flow by running the QoS to DRB mapping of the target base station. Finally, after synchronizing with the target base station 310, the user equipment 110 can resume the QoS flow data transmission and PDU session to the target base station 310. The QoS priority of the handover data packets can be preserved and processed with differentiated services.

[0054] Figure 4 Further illustration of the uplink data plane management method according to some embodiments of the present disclosure is provided. The host chip 410 and the baseband chip 420 can be part of the user equipment 110. As Figure 4 shown, multiple applications running on the host chip 410, designated as Appl, App2, and App3, and corresponding to PDU1, PDU2, and PDU3 respectively, can generate IP flows and provide them to the baseband chip 420 through the IP interface of the baseband chip 420. The baseband chip 420 can perform the mapping of the IP flow to the QoS flow and can provide the flow control on and off commands to the host chip 410.

[0055] The baseband chip 420 can identify the source configuration and determine the mapping between the QoS flow and the DRB for the source base station. For IP data packets that are being processed but not yet sent or confirmed, the baseband chip 420 can cache these packets and track the QFI corresponding to each DRB. In this example, DRB1, DRB2, and DRB3 exist on the source base station side. QFI1, QFI2, and QFI3, each of which has some unsent data and some unconfirmed data, are mapped to DRB1. QFI4 and QFI5, each of which has some unsent data and some unconfirmed data, are mapped to DRB2. QFI6, QFI7, and QFI8, each of which has some unsent data and some unconfirmed data, are mapped to DRB3. These DRBs can be further associated with various logical channels and can be performed in the radio link control (RLC), MAC, and PHY layers.

[0056] The baseband chip 420 can also identify the target configuration and determine the mapping between the QoS flow and the DRB for the target base station. Two examples, Case A and Case B, are shown, and this is specified in this way only for convenience and not to express order or priority. In the example of Case A, DRB4 (default radio bearer) is mapped to QFI1 and all unmapped high-priority data packets. DRB5 is mapped to QFI2, QFI3, and QFI4. DRB6 is mapped to QFI5 and QFI6. DRB7 is mapped to QFI7 and QFI8.

[0057] As shown in this example, four DRBs in the target correspond to three DRBs in the source. Other mappings are also possible. In Case B, there are only two queues corresponding to high priority and normal priority. In either Case A or Case B, the processing can proceed to the mapping of the logical channel and be passed through the protocol stack to the RLC, MAC, and PHY layers.

[0058] Figure 5 The sequential flow of some embodiments of the present disclosure is shown. As Figure 5 shown at the top, the baseband chip 420 of the user equipment 110 can initially be connected to the source base station 120 (these can be the same as the user equipment 110 and the source base station 120 mentioned above). Figure 3 Next, a handover trigger may occur. As described above, this handover can be based on measurement results or any other criteria. Therefore, the network can send an RRC reconfiguration message to the baseband chip 420 of the user equipment 110. From the perspective of the baseband chip 420 of the user equipment 110, receiving the RRC reconfiguration message can be a trigger to perform a handover.

[0059] In some embodiments, the baseband chip 420 of the user equipment 110 may immediately suspend all data transmissions on the source DRB resources. The baseband chip 420 of the user equipment 110 may enable flow control of the host chip 410 of the user equipment 110 by sending a flow control enable message to the host chip 410 to suspend all IP flows.

[0060] All uplink QoS flow data may be cached, including unacknowledged and unsent data in each QoS flow. Meanwhile, the source base station 120 may transmit any incoming DL data for the baseband chip 420 of the user equipment 110 to the target base station 310. The target base station 310 may perform DL data caching on this data. Other handover processes may also be performed at this time.

[0061] The baseband chip 420 of the user equipment 110 may send a PDCP end marker control PDU for each QoS flow to notify the source base station 120 that the baseband chip 420 of the user equipment 110 stops the QoS-to-DRB mapping of each QoS flow at this source BS 120.

[0062] The baseband chip 420 of the user equipment 110 may also reconfigure the QoS flows to the target resources. In particular, for each QoS flow, the baseband chip 420 may identify the possible corresponding radio bearers, cell configurations, etc. More specifically, upon receiving the RRC reconfiguration, the baseband chip 420 may reconfigure a new set of target QoS-to-DRB mappings, new target DRB resources, cell configurations, and logical channels.

[0063] The RRC Reconfigure (reconfiguration) message sent according to 3GPP TS 38.311 may provide target information, which includes the target cell ID, radio bearer configuration (which may be the same DRB resources as those of the source base station 120 or a different set of DRB resources from the source base station 120), cell group configuration (which may specify resources for carrier aggregation and component carriers), QoS-to-data radio bearer mapping (even if the DRB resource pipeline remains consistent with the source, the QoS-to-DRB mapping may be different), security parameters (broadly including, for example, encryption and integrity algorithms and encryption and integrity keys), the cell radio network temporary identifier (C-RNTI) at the target, random access channel (RACH) resources, such as pre-allocated preambles for physical random access channel (PRACH) access to the target cell, and the system information of the target cell. From the network perspective, if the UL data source terminates at the same UPF or PDU, the QoS flows of the PDU session may remain unchanged but may be routed through different DRBs in the target base station network.

[0064] Once the baseband chip 420 of the user equipment 110 has reconfigured the QoS flow to the target resource, the baseband chip 420 can forward the UL buffered data to the target resource. For example, in some embodiments, the baseband chip 420 can remap the source QoS data flow to the target resource. For example, the baseband chip 420 can re-run the mapping of the target QoS flow to the DRB to determine new target RBs / resources for each QoS flow data. For each QoS flow, unacknowledged data packets can be queued first, followed by unsent data packets.

[0065] As described above, there may be at least two different scenarios, which for convenience are labeled as Scenario A and Scenario B. In Scenario A, the target base station 310 can be a 5G base station. In this case, newly configured DRB and LC resources can be provided for the same QoS flow at the target. Thus, data packets can be routed to this exact QoS flow and DRB.

[0066] If there is no matching QoS configuration for the QoS flow, the QoS flow profile can be used to determine whether high-priority low-latency (LL) data packets need to be placed in the high-priority default QoS flow queue, and this data will be sent first with the highest priority when the target MAC UL scheduling algorithm is triggered for UL transmission.

[0067] In Scenario B, the target base station 310 can be 4G, 3G, 2G, or other non-3GPP. If there is no equivalent / matching QoS configuration for the QoS flow, the QoS flow profile can be used to determine whether high-priority LL data packets need to be placed in the high-priority default QoS flow queue, where the data will be sent first with the highest priority. The remaining data packets can be queued in a separate default non-high-priority queue, where the QoS profile score can be used to determine the transmission priority.

[0068] The baseband chip 420 of the user equipment 110 can use the pre-allocated PRACH preamble given in the RRC reconfiguration message to trigger a contention-free random access (CFRA) procedure in accordance with 3GPP standards (including random access request and response) to perform handover. Once the CFRA is successful, it can be considered that the baseband chip 420 of the user equipment 110 has been synchronized and connected to the target base station.

[0069] The baseband chip 420 of the user equipment 110 can then perform PDCP reconstruction. The baseband chip 420 can use a grant request to trigger UL data transmission for unacknowledged QoS data, unsent buffered QoS data, and new UL QoS data.

[0070] In some embodiments, the source handover data can be sent according to the LC priority of each QoS flow in each RB. Each QoS flow can transmit data packets in the following order: unacknowledged data packets from the source, and then unsent data packets from the source.

[0071] In each QoS flow queue, once the QoS flow buffer level is below the threshold, the flow control of the host chip 410 of the user equipment 110 can be triggered to be closed. The mapping of the QoS flow to the IP flow can be looked up to retrieve the list of IP flows corresponding to a given QoS flow.

[0072] Then, the flow control can be released for each IP flow in the list of IP flows corresponding to the QoS flows whose cached data is reduced to the threshold. Subsequently, the new application data of these incoming IP flows from the host chip 410 of the user equipment 110 can be queued in the corresponding QoS flow queues to be sent after the existing source data is pushed out.

[0073] Therefore, some embodiments allow the user equipment to effectively perform 5G UL handover with lossless, seamless, in-order, and optimized QoS flow data transmission with differentiated services, and can enhance UE performance, especially for ultra-reliable low-latency communication (URLLC) applications.

[0074] Some embodiments can have various benefits and / or advantages. For example, some embodiments can be implemented practically and directly in the software running on the user equipment hardware. When a handover occurs from the source base station to the target base station, some embodiments can ensure lossless UL data transmission. When a handover occurs from the source base station to the target base station, some embodiments also provide differentiated services with optimized QoS priorities for each UL QoS flow. In addition, some embodiments can provide improved user equipment handover performance with UL data continuity. Further, in some embodiments, even if the matching QoS flow or DRB at the target is not differentiated by the target BS resources, the low-latency QoS flow can be preferentially used for UL delivery at the target. In addition, some embodiments can prevent data loss by allowing the flow control of the source data to be suspended before the handover. Some embodiments can also use the mapping of the QoS flow to the source IP flow on a per-QoS-flow basis to recover the new data after the handover to accelerate the QoS data recovery. Some embodiments can also eliminate UL data cache overflow and data loss at the user equipment during the handover. In addition, some embodiments can eliminate out-of-order data delivery for each QoS flow with the best-matched target radio bearer and cell configuration during the handover. Further, some embodiments can provide general and optimized uplink data transmission when a handover occurs from 5G to 4G or a non-3GPP base station.

[0075] Various modifications of some embodiments are feasible. For example, some embodiments can prioritize the data transmission of the highest QoS delay stream for application to an inter-RAT uplink handover data management scheme between 5G and 2G / 3G or non-3GPP systems without QoS configuration. Some embodiments can similarly be modified to allow non-3GPP, 4G / 3G / 2G to switch back to a QoS-enabled 5G system through optimized QoS flow transmission.

[0076] The software and hardware methods and systems disclosed herein, such as Figures 2 to 5 the methods shown, can be implemented by any suitable node in a wireless network. For example, Figure 6 and Figure 7 show the corresponding apparatuses 600 and 700, and Figure 8 shows an exemplary wireless network 800 according to some embodiments of the present disclosure, in which some aspects of the present disclosure can be implemented.

[0077] Figure 6 shows a block diagram of an apparatus 600 including a baseband chip 602, a radio frequency chip 604, and a host chip 606 according to some embodiments of the present disclosure. The apparatus 600 can be Figure 8 an example of any suitable node in the wireless network 800 in Figure 6 , such as a user equipment 802 or a network node 804. As Figure 7 shown, the apparatus 600 can include a baseband chip 602, a radio frequency chip 604, a host chip 606, and one or more antennas 610. In some embodiments, as described below with respect to Figures 2 - 5 , the baseband chip 602 is implemented by a processor 702 and a memory 704, and the radio frequency chip 604 is implemented by a processor 702, a memory 704, and a transceiver 706. In some embodiments, the baseband chip 602 can implement all or part of the method and generate and process Figure 4 the messages shown in Figure 4the host chip 410 therein. In addition to the on-chip memory (also referred to as "internal memory" or "local memory", such as registers, buffers, or caches) on each chip 602, 604, or 606, the device 600 may also include an external memory 608 (e.g., system memory or main memory), which may be shared by each chip 602, 604, or 606 via a system / main bus. Although in Figure 6 the baseband chip 602 is shown as a standalone SoC, it can be understood that, in one example, the baseband chip 602 and the radio frequency chip 604 may be integrated into one SoC; in another example, as described above, the baseband chip 602 and the host chip 606 may be integrated into one SoC; in yet another example, the baseband chip 602, the radio frequency chip 604, and the host chip 606 may be integrated into one SoC.

[0078] In the uplink, the host chip 606 may generate raw data and send it to the baseband chip 602 for encoding, modulation, and mapping. As described above, the data from the host chip 606 may be associated with various IP flows. The baseband chip 602 may map those IP flows to QoS flows and perform the additional data plane management functions as described above. The baseband chip 602 may also access the raw data generated by the host chip 606 and stored in the external memory 608, e.g., using direct memory access (DMA). The baseband chip 602 may first encode (e.g., via source coding and / or channel coding) the raw data and modulate the encoded data using any suitable modulation technique, such as multi-phase pre-shared key (MPSK) modulation or quadrature amplitude modulation (QAM). The baseband chip 602 may perform any other functions, such as symbol or layer mapping, to convert the raw data into a signal that can be used to modulate a carrier frequency for transmission. In the uplink, the baseband chip 602 may send the modulated signal to the radio frequency chip 604. The radio frequency chip 604 may convert the modulated signal in digital form into an analog signal, i.e., a radio frequency signal, via a transmitter (Tx), and perform any suitable front-end radio frequency functions, such as filtering, upconversion, or sample rate conversion. The antenna 610 (e.g., an antenna array) may transmit the radio frequency signal provided by the transmitter of the radio frequency chip 604.

[0079] In the downlink, antenna 610 can receive radio frequency signals and transfer the radio frequency signals to the receiver (Rx) of radio frequency chip 604. The radio frequency chip 604 can perform any suitable front-end radio frequency functions, such as filtering, down-conversion, or sample rate conversion, and convert the radio frequency signals into low-frequency digital signals (baseband signals) that can be processed by the baseband chip 602. In the downlink, the baseband chip 602 can demodulate and decode the baseband signals to extract the original data that can be processed by the host chip 606. The baseband chip 602 can perform additional functions, such as error checking, demapping, channel estimation, descrambling, etc. The original data provided by the baseband chip 602 can be directly sent to the host chip 606 or stored in the external memory 608.

[0080] As Figure 7 shown, node 700 can include a processor 702, a memory 704, and a transceiver 706. These components are shown as being connected to each other via a bus 708, but other connection types are also allowed. When node 700 is a user equipment 802, additional components, such as a user interface (UI), sensors, etc., may also be included. Similarly, when node 700 is configured as a core network element 806, node 700 can be implemented as a blade in a server system. Other implementations are also possible.

[0081] The transceiver 706 can include any suitable device for transmitting and / or receiving data. Although only one transceiver 706 is shown for simplicity of illustration, node 700 can include one or more transceivers. Antenna 710 is shown as a possible communication mechanism for node 700. Multiple antennas and / or antenna arrays can be used. In addition, examples of node 700 can use wired technologies instead of (or in combination with) wireless technologies for communication. For example, network node 804 can communicate wirelessly with user equipment 802 and can communicate with core network element 806 via a wired connection (e.g., via an optical fiber cable or a coaxial cable). Other communication hardware, such as a network interface card (NIC), may also be included.

[0082] As Figure 7As shown, node 700 may include a processor 702. Although only one processor is shown, it is understood that multiple processors may be included. Processor 702 may include a microprocessor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described in this disclosure. Processor 702 may be a hardware device having one or more processing cores. Processor 702 may execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise, software should be broadly interpreted to represent instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, processes, functions, etc. Software may include computer instructions written in an interpreted language, a compiled language, or machine code. Under the broad category of software, other techniques indicating hardware are also allowed. Processor 702 may be a baseband chip, such as Figure 6 the baseband chip 602 in Figure 7 . Node 700 may also include other processors not shown, such as the central processing unit, graphics processor, etc. of the device. Processor 702 may include internal memory (also referred to as local memory,

[0083] not shown in Figure 7 ) that can be used as L2 data memory. Processor 702 may include a radio frequency chip. For example, the radio frequency chip may be integrated into the baseband chip or provided separately. Processor 702 may be configured to operate as a modem of node 700, or may be an element or component of a modem. Other arrangements and configurations are also allowed. Figure 6the external memory 608 therein. The memory 704 can be shared by the processor 702 and other components of the node 700, such as a graphics processor or a central processing unit (not shown).

[0084] As Figure 8 shown, the wireless network 800 can include a network of nodes such as, for example, a UE 802, a network node 804, and a core network element 806. The user equipment 802 can be any terminal device, such as a mobile phone, a desktop computer, a laptop computer, a tablet computer, a vehicle-mounted computer, a game console, a printer, a positioning device, a wearable electronic device, a smart sensor, or any other device capable of receiving, processing, and transmitting information, such as any member of a vehicle-to-everything (V2X) network, a trunked network, a smart grid node, or an Internet of Things (IoT) node. It can be understood that the user equipment 802 is shown as a mobile phone for illustration only and not for limitation.

[0085] The network node 804 can be a device that communicates with the user equipment 802, such as a wireless access point, a base station (BS), a Node B (NodeB), an evolved Node B (eNodeB or eNB), a next-generation Node B (gNodeB or gNB), a trunking master node, etc. The network node 804 can have a wired connection to the user equipment 802, a wireless connection to the user equipment 802, or any combination thereof. The network node 804 can be connected to the user equipment 802 through multiple connections, and the user equipment 802 can be connected to other access nodes in addition to the network node 804. The network node 804 can also be connected to other UEs. It can be understood that the network node 804 is shown as a wireless tower for illustration only and not as a limitation.

[0086] The core network element 806 can serve the network node 804 and the user equipment 802 to provide core network services. Examples of the core network element 806 can include a home subscriber server (HSS), a mobility management entity (MME), a serving gateway (SGW), or a packet data network gateway (PGW). These are examples of core network elements of an evolved packet core (EPC) system, which is the core network of an LTE system. Other core network elements can be used in LTE and other communication systems. In some embodiments, the core network element 806 includes an access and mobility management function (AMF) device, a session management function (SMF) device, or a user plane function (UPF) device of the core network of an NR system. It can be understood that the core network element 806 is shown as a set of rack-mounted servers for illustration and not for limitation.

[0087] The core network element 806 can be connected to a large network such as the Internet 808 or another IP network to transmit packet data over any distance. In this way, data from the user equipment 802 can be transmitted to other UEs connected to other access points, including for example a computer 810 connected to the Internet 808 using a wired or wireless connection, or a tablet 812 wirelessly connected to the Internet 808 via a router 814. Thus, the computer 810 and the tablet 812 provide additional examples of possible UEs, and the router 814 provides an example of another possible access node.

[0088] A general example of a rack-mounted server is provided as an illustration of the core network element 806. However, there may be multiple elements in the core network, including a database server, such as the database 816, and a security and authentication server, such as the authentication server 818. For example, the database 816 can manage data related to user subscriptions to network services. A home location register (HLR) is an example of a standardized database of user information in a cellular network. Similarly, the authentication server 818 can handle the authentication of users, sessions, etc. In an NR system, an authentication server function (AUSF) device can be a specific entity that performs user equipment authentication. In some embodiments, a single server rack can handle multiple such functions, such that the connections between the core network element 806, the authentication server 818, and the database 816 can be local connections within a single rack.

[0089] Figure 8 Each element of can be considered a node of the wireless network 800. More details regarding possible implementations of the nodes are provided by way of example in the description of the node 700 above in Figure 7 The node 700 can be configured as Figure 8 the user equipment 802, the network node 804, or the core network element 806 in. Similarly, the node 700 can also be configured as Figure 8 the computer 810, the router 814, the tablet 812, the database 816, or the authentication server 818 in.

[0090] In various aspects of the present disclosure, the functions described in the present disclosure can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, these functions can be stored or encoded as instructions or code on a non-transitory computer-readable medium. The computer-readable medium includes computer storage media. The storage media can be a computing device (such as Figure 7any available medium accessible by the nodes 700) therein. By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, HDD such as magnetic disk storage or other magnetic storage devices, flash drives, SSDs or any other medium that can be used to carry or store the required program code in the form of instructions or data structures and accessible by a processing system (such as a mobile device or a computer). The disks and optical disks used in this disclosure include CDs, laser disks, optical disks, DVDs, and floppy disks, where disks generally reproduce data magnetically, while optical disks use lasers to reproduce data optically. Combinations of the above should also be included within the scope of computer-readable media.

[0091] According to one aspect of the present disclosure, a method for switching continuity may include caching data packets at a user equipment based on a triggering event. The data packets may be mapped to a first quality of service flow and associated with a first radio resource at a source network node. The method may further include identifying a second quality of service flow associated with a second radio resource at a target network node. The method may further include remapping from the first quality of service flow to the second quality of service flow. The method may further include sending the cached data packets from the user equipment to the target network node based on the remapping.

[0092] In some embodiments, the method may further include applying flow control to all data packets arriving at the baseband chip of the user equipment on a per quality of service flow basis. The applying of the flow control is in response to the triggering event.

[0093] In some embodiments, the method may further include releasing the flow control when the data cache including the cached data packets drops below a threshold.

[0094] In some embodiments, the releasing of the flow control may include selectively releasing the flow control on a per Internet protocol flow basis based on the association with the second quality of service flow.

[0095] In some embodiments, the data packets may be mapped to a first quality of service flow using an Internet protocol flow to quality of service flow mapping.

[0096] In some embodiments, the triggering event may be receiving a radio reconfiguration message indicating a handover.

[0097] In some embodiments, the identifying of the second quality of service flow associated with the second radio resource at the target network node may include mapping a data radio bearer at the target network node to a second quality of service flow that matches or approximates the first quality of service flow.

[0098] According to another aspect of the present disclosure, a device (e.g., a user equipment) for switching continuity may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code may be configured to, by the at least one processor, cause the device to cache data packets at the user equipment at least based on a triggering event. The data packets may be mapped to a first quality of service flow and associated with a first radio resource at a source network node. The at least one memory and the computer program code may further be configured to, by the at least one processor, cause the device to at least identify a second quality of service flow associated with a second radio resource at a target network node. The at least one memory and the computer program code may be further configured to, by the at least one processor, cause the device to at least remap from the first quality of service flow to the second quality of service flow. The at least one memory and the computer program code may also be configured to, by the at least one processor, cause the device to at least send the cached data packets from the user equipment to the target network node based on the remapping.

[0099] In some embodiments, the at least one memory and the computer program code may further be configured to, by the at least one processor, cause the device to at least apply flow control to all data packets arriving at a baseband chip of the user equipment on a per quality of service flow basis, wherein the applying of the flow control is in response to the triggering event.

[0100] In some embodiments, the at least one memory and the computer program code may further be configured to, by the at least one processor, cause the device to at least lift the flow control when a data cache including the buffered data packets drops below a threshold.

[0101] In some embodiments, the lifting of the flow control includes selectively lifting the flow control on a per Internet protocol flow basis based on an association with the second quality of service flow.

[0102] In some embodiments, the data packets are mapped to the first quality of service flow using a mapping from Internet protocol flows to quality of service flows.

[0103] In some embodiments, the triggering event may be a received radio reconfiguration message indicating a handover.

[0104] In some embodiments, the identifying of the second quality of service flow associated with the second radio resource at the target network node may include mapping a data radio bearer at the target network node to a second quality of service flow that matches or approximates the first quality of service flow.

[0105] In accordance with yet another aspect of the present disclosure, a non - volatile computer - readable medium encoded with instructions, when executed in the hardware of a user device, causes the user device to perform a process for handover continuity. The process may include caching data packets at the user device based on a trigger event. The data packets may be mapped to a first quality - of - service (QoS) flow and associated with a first radio resource at a source network node. The process may further include identifying a second QoS flow associated with a second radio resource at a target network node. The process may further include remapping from the first QoS flow to the second QoS flow. The process may further include sending the cached data packets from the user device to the target network node based on the remapping.

[0106] In some embodiments, the process may further include applying flow control to all data packets arriving at the baseband chip of the user device on a per - QoS - flow basis, where the applying of flow control is in response to the trigger event.

[0107] In some embodiments, the process may further include releasing the flow control when a data cache including the buffered data packets drops below a threshold.

[0108] In some embodiments, the releasing of the flow control may include selectively releasing flow control on a per - Internet - protocol - flow basis based on the association with the second QoS flow.

[0109] In some embodiments, the data packets may be mapped to the first QoS flow using an Internet - protocol - flow - to - QoS - flow mapping.

[0110] In some embodiments, the trigger event may be the receipt of a radio reconfiguration message indicating a handover.

[0111] In some embodiments, the identifying of the second QoS flow associated with the second radio resource at the target network node may include mapping a data radio bearer at the target network node to a second QoS flow that matches or approximates the first QoS flow.

[0112] The above description of specific embodiments will disclose the general nature of the present disclosure. Others can easily modify and / or adapt these specific embodiments for various applications by applying knowledge within the scope of the art, without excessive experimentation and without departing from the general concept of the present disclosure. Therefore, based on the teachings and guidance presented herein, such modifications and adaptations are intended to be within the equivalent meaning and scope of the disclosed embodiments. It should be understood that the language or terms herein are for the purpose of description rather than limitation, such that the terms or language of this specification will be interpreted by those skilled in the art according to the teachings and guidance.

[0113] Embodiments of the present disclosure have been described above by means of functional blocks that implement specific functions and their relationships. For ease of description, the boundaries of these functional blocks are arbitrarily defined herein. Other boundaries may be defined as long as the specified functions and relationships are properly implemented.

[0114] The Summary of the Invention and Abstract sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the (one or more) inventors, and are thus not intended to limit the present disclosure and the appended claims in any way.

[0115] Various functional blocks, modules, and steps have been disclosed above. The particular arrangements provided are illustrative and not restrictive. Thus, the functional blocks, modules, and steps may be reordered or combined in a manner different from the examples provided above. Similarly, some embodiments include only a subset of the functional blocks, modules, and steps, and any such subset is permitted.

[0116] The breadth and scope of the present disclosure should not be limited by any of the above exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

1. A method for handover continuity, comprising: Caching data packets at a user equipment based on a triggering event, where the data packets are mapped to a first Quality of Service (QoS) flow and associated with a first radio resource at a source network node; Identifying a second QoS flow associated with a second radio resource at a target network node; Remapping from the first QoS flow to the second QoS flow; And Sending the cached data packets from the user equipment to the target network node based on the remapping, where the method further comprises: Applying flow control to all data packets arriving at a baseband chip of the user equipment on a per-QoS-flow basis, where the applying of the flow control is in response to the triggering event; and Releasing the flow control when a data cache including the cached data packets drops below a threshold; where the releasing of the flow control includes selectively releasing the flow control on a per-Internet Protocol (IP) flow basis based on the association with the second QoS flow.

2. The method according to claim 1, wherein The data packets are mapped to the first QoS flow using an IP flow to QoS flow mapping.

3. The method according to claim 1, wherein The triggering event includes receiving a radio reconfiguration message indicating a handover.

4. The method according to claim 1, wherein identifying the second QoS flow associated with the second radio resource at the target network node comprises mapping a data radio bearer at the target network node to a second QoS flow that matches or approximates the first QoS flow.

5. An apparatus for handover continuity, comprising: At least one processor; And At least one memory including computer program code, where the at least one memory and the computer program code are configured to, by the at least one processor, cause the apparatus to at least: Cache data packets at a user equipment based on a triggering event, where the data packets are mapped to a first QoS flow and associated with a first radio resource at a source network node; Identify a second QoS flow associated with a second radio resource at a target network node; Remap from the first QoS flow to the second QoS flow; And Send the cached data packets from the user equipment to the target network node based on the remapping, where the at least one memory and the computer program code are further configured to, by the at least one processor, cause the apparatus to at least: Apply flow control to all data packets arriving at a baseband chip of the user equipment on a per-QoS-flow basis, where the applying of the flow control is in response to the triggering event; And Release the flow control when a data cache including the cached data packets drops below a threshold, where the releasing of the flow control includes selectively releasing the flow control on a per-IP flow basis based on the association with the second QoS flow.

6. The device according to claim 5, wherein, The data packets are mapped to the first QoS flow using an IP flow to QoS flow mapping.

7. The apparatus according to claim 5, wherein, The triggering event includes receiving a radio reconfiguration message indicating a handover.

8. The apparatus according to claim 5, wherein identifying the second quality of service flow associated with the second radio resource at the target network node includes mapping the data radio bearer at the target network node to a second quality of service flow that matches or approximates the first quality of service flow.

9. A non - volatile computer - readable medium encoded with instructions that, when executed in the hardware of a user equipment, causes the user equipment to perform a process for handover continuity, the process comprising: Buffering data packets at the user equipment based on a trigger event, wherein the data packets are mapped to a first quality of service flow and are associated with a first radio resource at a source network node; Identifying a second quality of service flow associated with a second radio resource at a target network node; Remapping from the first quality of service flow to the second quality of service flow; And Sending the buffered data packets from the user equipment to the target network node based on the remapping, wherein the process further comprises: Applying flow control to all data packets arriving at the baseband chip of the user equipment on a per - quality - of - service - flow basis, wherein the applying of the flow control is in response to the trigger event; and Removing the flow control when the data buffer including the buffered data packets drops below a threshold, wherein removing the flow control includes selectively removing the flow control on a per - Internet - protocol - flow basis based on the association with the second quality of service flow.

10. The non-volatile computer-readable medium according to claim 9, wherein, The data packets are mapped to the first quality of service flow using a mapping from Internet - protocol flows to quality - of - service flows.

11. The non-volatile computer-readable medium according to claim 9, wherein, The trigger event includes receiving a radio reconfiguration message indicating a handover.

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