Devices and methods for QOS flow management for networked control systems

Abstract

A UE (110) for communication via a base station (120) in a mobile network (100) is disclosed. The UE (110) is configured to implement a Packet Data Convergence Protocol, PDCP, entity, wherein the PDCP entity comprises at least two different transmission buffers and wherein the PDCP entity is configured to assign a plurality of packets associated with one or more data flows to the at least two different transmission buffers. The PDCP entity of the UE (110) allows for a more efficient packet management and thereby allows increasing the performance within a mobile network (100), for instance, a mobile network implementing a networked control system.

Description

[0001] DEVICES AND METHODS FOR QOS FLOW MANAGEMENT FOR NETWORKED CONTROL SYSTEMS

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to wireless communications. More specifically, the present disclosure relates to devices and methods for QoS flow management in a mobile network, in particular for Networked Control Systems based on a 3GPP mobile network.

[0004] BACKGROUND

[0005] Network control systems (NCSs) are control applications that are closed over a mobile communication network. Such applications are commonly found in industrial scenarios. Some prominent examples are process automation, smart factory, remotely controlled robots, or UAVs. An NCS consists of a plant, a sensor, a controller and an actuator. The controller’s goal is to drive the plant’s state, i.e., system state, to a desired value through the control inputs. The system state is frequently measured by one or multiple sensors, e.g., temperature sensor, position sensor. The actuator is the component applying the controller’s input to the plant, thereby, has the ability to manipulate the system state. A common example of an actuator is a servo motor, which can change the position of a robot.

[0006] In industrial applications, such NCSs, the communication services provided by the mobile network have a significant impact on the resulting control performance. For instance, if a controller that is operating remotely does not have up-to-date information about the system state, or similarly, if an actuator applies inaccurate control input due to high delay or packet loss on the controller-to-actuator link, the control performance drops, leading to the instability of the system. Usually, the data traffic in NCSs may be generated in a time-triggered or an event-triggered manner. Time-triggered means that the data source periodically generates and transmits a new data packet in constant time intervals, e.g., every 10 milliseconds. Event-triggered means that the data source transmits only if an “event” has occurred. For instance, a sensor measurement is transmitted only if the change in the system state is larger than a pre-defined threshold.

[0007] In NCSs, some packets are more important than others for the sake of control system’s performance, which is a property not generalizable for all types of applications (e.g. for a file transfer, each byte of the data is equally important to reproduce the file on the other side of the network). For instance, consider the sensor-to-controller link. Here, the benefit of transmitting a fresh sensor measurement is higher than transmitting an outdated one. Additionally, some sensor measurements carry more important or critical information than others in order to achieve a better (application) performance or to maintain the system stability, which calls for a differentiated treatment of data packets within the underlying (user plane) communication stack, e.g., 5G RAN.

[0008] SUMMARY

[0009] It is an objective of the present disclosure to provide improved devices and methods devices and methods for QoS flow management for Networked Control Systems based on a mobile network.

[0010] The foregoing and other objectives are achieved by the subject matter of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

[0011] According to a first aspect a user equipment, UE, for communication via a base station in a mobile network is provided. The UE is configured to implement a Packet Data Convergence Protocol, PDCP, entity, wherein the PDCP entity comprises at least two different transmission buffers for storing packets to be transmitted to the base station and wherein the PDCP entity is configured to assign a plurality of packets, in particular PDCP SDUs, associated with one or more, in particular at least two different data flows, e.g. QoS flows to the at least two different transmission buffers. Thus, the PDCP entity of the UE according to the first aspect allows for a more efficient packet management and thereby allows increasing the performance within a mobile network, for instance, a mobile network implementing a networked control system. More specifically, network resources may be utilized more efficiently by prioritizing more important packets over less important ones. In return, application performance is improved. Moreover, data staleness due to congestion may be prevented or at least mitigated, by discarding outdated packets, motivated by the nature of real-time networked control applications.

[0012] In a further possible implementation form, the UE is configured to implement a protocol stack comprising a PDCP layer, wherein the PDCP entity is implemented in the PDCP layer. This allows to implement the PDCP layer within a protocol stack ofthe UE.

[0013] In a further possible implementation form, each of the plurality of packets comprises a Quality of Service, QoS, Flow Identifier, QFI, and wherein the PDCP entity is configured to assign each of the plurality of packets associated with the one or more, in particular at least two different data flows, e.g. QoS flows to the at least two different transmission buffers based on the QFI of each packet. This allows for an efficient distribution of the plurality of packets.

[0014] In a further possible implementation form, when assigning a respective packet to the respective transmission buffer, the PDCP entity is configured to discard and / or reorder one or more further packets previously assigned to the transmission buffer and waiting to be transmitted. Thus, network resources may be utilized more efficiently by prioritizing more important packets over less important ones. Moreover, energy may be saved by discarding outdated packets that lose validity / relevance during service / over time.

[0015] In a further possible implementation form, the PDCP entity is configured to receive PDCP configuration information, wherein for each of the one or more data flows the PDCP entity is configured to discard and / or reorder the one or more further packets previously assigned to the respective transmission buffer based on the PDCP configuration information. This allows for an efficient control and configuration of the PDCP entity of the UE according to the first aspect.

[0016] In a further possible implementation form, the PDCP entity is configured to discard and / or reorder the one or more further packets previously assigned to the respective transmission buffer and waiting to be transmitted based on an importance indication associated with each packet of a data flow. Thus, network resources may be utilized more efficiently by prioritizing more important packets over less important ones.

[0017] In a further possible implementation form, the PDCP entity is configured to receive for each packet of the one or more data flows an IP, RTP, and / or Ethernet header, wherein the PDCP entity is configured to extract the importance indication associated with each packet of a data flow from the IP, RTP, and / or Ethernet header of the packet. This allows to efficiently provide the importance indication associated with each packet to the PDCP entity.

[0018] In a further possible implementation form, the importance indication associated with each packet of a data flow is provided by a UE application associated with the data flow or is based on a packet importance map obtained from an application function of the mobile network, wherein the application function is associated with the data flow. This allows to efficiently provide the importance indication associated with each packet to the PDCP entity of the UE according to the first aspect. As will be appreciated, an application function may be associated with a plurality of data flows. In a further possible implementation form, the UE is configured to receive a RRCReconfiguration message from the base station and to implement the PDCP entity in accordance with information contained in the RRCReconfiguration message. In other words, the RRCReconfiguration message may contain and / or indicate one or more configuration parameters for operating the PDCP entity. Thus, the configuration of the PDCP entity of the UE according to the first aspect may be seamlessly integrated into existing mobile networks.

[0019] In a further possible implementation form, the information is contained in a field of a pdcp-Config information element of the RRCReconfiguration message. Thus, the configuration of the PDCP entity may be seamlessly integrated into existing mobile networks.

[0020] According to a second aspect a method is provided for operating a user equipment, UE, for communication via a base station in a mobile network. The method according to the second aspect comprises a step of implementing a Packet Data Convergence Protocol, PDCP, entity, wherein the PDCP entity comprises at least two different transmission buffers for storing packets to be transmitted to the base station and wherein the PDCP entity is configured to assign a plurality of packets, in particular PDCP SDUs, associated with at least two different data flows, e.g. QoS flows to the at least two different transmission buffers.

[0021] The method according to the second aspect can be performed by the UE according to the first aspect. Thus, further features of the method according to the second aspect result directly from the functionality of the UE according to the first aspect as well as its different implementation forms described above and below.

[0022] According to a third aspect a base station for communication with a user equipment, UE, in the mobile network is provided. The base station is configured to implement a Packet Data Convergence Protocol, PDCP, entity, wherein the PDCP entity comprises at least two different transmission buffers for storing packets to be transmitted to the UE and wherein the PDCP entity is configured to assign a plurality of packets, in particular PDCP SDUs, associated with one or more, in particular at least two different data flows, e.g. QoS flows to the at least two different transmission buffers. Thus, the PDCP entity of the base station according to the third aspect allows for a more efficient packet management and thereby allows increasing the performance within a mobile network, for instance, a mobile network implementing a networked control system. More specifically, network resources may be utilized more efficiently by prioritizing more important packets over less important ones. In return, application performance is improved. Moreover, data staleness due to congestion may be prevented or at least mitigated, by discarding outdated packets, motivated by the nature of real-time networked control applications.

[0023] In a further possible implementation form, the base station is configured to implement a protocol stack comprising a PDCP layer and wherein the PDCP entity is implemented in the PDCP layer. This allows to implement the PDCP layer within a protocol stack of the base station.

[0024] In a further possible implementation form, each of the plurality of packets comprises a Quality of Service, QoS, Flow Identifier, QFI, and wherein the PDCP entity is configured to assign each of the plurality of packets associated with the one or more, in particular at least two different data flows to the at least two different transmission buffers based on the QFI of each packet. This allows for an efficient distribution of the plurality of packets.

[0025] In a further possible implementation form, when assigning a respective packet to the respective transmission buffer, the PDCP entity is configured to discard and / or reorder one or more further packets previously assigned to the transmission buffer and waiting to be transmitted. Thus, network resources may be utilized more efficiently by prioritizing more important packets over less important ones. Moreover, energy may be saved by discarding outdated packets that lose validity / relevance during service / over time. In a further possible implementation form, the PDCP entity is configured to receive PDCP configuration information and wherein for each of the one or more data flows the PDCP entity is configured to discard and / or reorder the one or more further packets previously assigned to the transmission buffer based on the PDCP configuration information. This allows for an efficient control and configuration of the PDCP entity of the base station according to the third aspect.

[0026] In a further possible implementation form, the PDCP entity is configured to discard and / or reorder the one or more further packets previously assigned to the transmission buffer and waiting to be transmitted based on an importance indication associated with each packet of a data flow. Thus, network resources may be utilized more efficiently by prioritizing more important packets over less important ones.

[0027] In a further possible implementation form, the PDCP entity is configured to receive for each packet of the one or more data flows an IP, RTP, and / or Ethernet header and wherein the PDCP entity is configured to extract the importance indication associated with each packet of a data flow from the IP, RTP, and / or Ethernet header of the packet. This allows to efficiently provide the importance indication associated with each packet to the PDCP entity of the base station according to the third aspect.

[0028] In a further possible implementation form, the importance indication associated with each packet of a data flow is based on a packet importance map obtained from an application function of the mobile network, wherein the application function is associated with the data flow. This allows to efficiently provide the importance indication associated with each packet to the PDCP entity of the base station according to the third aspect.

[0029] According to a fourth aspect a method is provided for operating a base station for communication with a user equipment, UE, in the mobile network. The method according to the fourth aspect comprises a step of implementing a Packet Data Convergence Protocol, PDCP, entity, wherein the PDCP entity comprises at least two different transmission buffers for storing packets to be transmitted to the UE and wherein the PDCP entity is configured to assign a plurality of packets, in particular PDCP SDUs, associated with one or more, in particular at least two different data flows, e.g. QoS flows to the at least two different transmission buffers.

[0030] The method according to the fourth aspect can be performed by the base station according to the third aspect. Thus, further features of the method according to the fourth aspect result directly from the functionality of the base station according to the third aspect as well as its different implementation forms described above and below.

[0031] According to a fifth aspect, a computer program product is provided, comprising a computer-readable storage medium for storing a program code which causes a computer or a processor to perform the method according to the second aspect, or the method according to the fourth aspect, when the program code is executed by the computer or the processor.

[0032] Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the following, embodiments of the present disclosure are described in more detail with reference to the attached figures and drawings, in which:

[0034] Fig. 1 shows a schematic diagram illustrating a mobile telecommunication system comprising a UE according to an embodiment and a base station according to an embodiment for communication with a data network;

[0035] Figs. 2a and 2b are schematic diagrams illustrating packet management issues encountered with a conventional UE and a conventional base station;

[0036] Fig. 3a is a schematic diagram illustrating a PDCP entity implemented by a UE or base station according to an embodiment for efficient packet management;

[0037] Fig 3b is a schematic diagram illustrating a PDCP entity implemented by a UE according to an embodiment for efficient packet management;

[0038] Fig. 4a is a signalling diagram illustrating the provisioning of a PDCP entity configuration from a network to a UE according to an embodiment;

[0039] Fig. 4b is a signalling diagram illustrating the provisioning of a PDCP entity configuration from abase station to a UE according to an embodiment;

[0040] Fig. 5 is a schematic diagram illustrating interactions between a UE according to an embodiment, a base station according to an embodiment and network functions of a core network of a mobile network;

[0041] Fig. 6a is a signalling diagram illustrating the interaction between an AMF and a base station according to an embodiment for PDU session resource setup;

[0042] Fig. 6b is a signalling diagram illustrating the interaction between an AMF and a base station according to an embodiment for PDU session resource modification;

[0043] Figs. 7a, 7b, and 7c are schematic diagrams illustrating different PDU types used by a UE and / or a base station according to an embodiment for efficient packet management;

[0044] Fig. 8 is a flow diagram illustrating a method for operating a UE according to an embodiment; and

[0045] Fig. 9 is a flow diagram illustrating a method for operating a base station according to an embodiment.

[0046] In the following, identical reference signs refer to identical or at least functionally equivalent features.

[0047] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] In the following description, reference is made to the accompanying figures, which form part of the disclosure, and which show, by way of illustration, specific aspects of embodiments of the present disclosure or specific aspects in which embodiments of the present disclosure may be used. It is understood that embodiments of the present disclosure may be used in other aspects and comprise structural or logical changes not depicted in the figures. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

[0049] For instance, it is to be understood that a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if one or a plurality of specific method steps are described, a corresponding device may include one or a plurality of units, e.g. functional units, to perform the described one or plurality of method steps (e.g. one unit performing the one or plurality of steps, or a plurality of units each performing one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures. Moreover, if a specific apparatus is described based on one or a plurality of units, e.g. functional units, a corresponding method may include one step to perform the functionality of the one or plurality of units (e.g. one step performing the functionality of the one or plurality of units, or a plurality of steps each performing the functionality of one or more of the plurality of units), even if such one or plurality of steps are not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary embodiments and / or aspects described herein may be combined with each other, unless specifically noted otherwise.

[0050] Figure 1 shows a schematic diagram illustrating a mobile telecommunication system 100 comprising at least one user equipment, UE, 110 according to an embodiment, at least one base station 120 according to an embodiment. In an embodiment, the mobile telecommunication system 100 comprises or is a 3rd Generation Partnership Project (3GPP) mobile telecommunication system, which may further comprise or be connected with a user plane function (UPF) 160 for communicating with an application server 180 of a data network 170. The system illustrated in figure 1 may be a sensor application sending sensor data packets from a sensor 117 of the UE to a remote monitor or controller 180 in an industrial setting.

[0051] As illustrated in figure 1, the UE 110 may comprise a processing circuitry, e.g. one or more processors 111 and a communication interface 113. The processing circuitry 111 may be implemented in hardware and / or software. The hardware may comprise digital circuitry, or both analog and digital circuitry. Digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), or one or more general- purpose processors. Moreover, the UE 110 may comprise a memory 115 configured to store executable program code which, when executed by the processing circuitry 111, causes the UE 110 to perform the functions and operations described herein.

[0052] Likewise, the base station 120 may comprise a processing circuitry, e.g. one or more processors 121 and a communication interface 123. The processing circuitry 121 may be implemented in hardware and / or software. The hardware may comprise digital circuitry, or both analog and digital circuitry. Digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), or one or more general- purpose processors. Moreover, the base station 120 may comprise a memory 125 configured to store executable program code which, when executed by the processing circuitry 121, causes the base station 120 to perform the functions and operations described herein.

[0053] As illustrated in figure 1, the UE 110, in particular the processing circuitry 111 thereof may implement a protocol stack comprising a SDAP layer 11 la, a PDCP layer 11 lb, a RLC layer 111c, a MAC layer 11 Id and a PHY layer 11 le. Likewise, the base station 120, e.g. gNB 120, in particular the processing circuitry 121 thereof may implement a protocol stack comprising a SDAP layer 121a, a PDCP layer 121b, a RLC layer 121c, a MAC layer 12 Id and a PHY layer 12 le. As will be appreciated, sensor data packets from the sensor 117 of the UE 110 are transmitted via the uplink Uu interface to the serving base station 120, e.g. gNB 120 while traversing the user plane protocol stack of the RAN. Before describing detailed embodiments of the UE 110, and the base station 120, in the following some technical background as well as terminology will be introduced making use of one or more of the following abbreviations and / or acronyms:

[0054] PDCP Packet Data Convergence Protocol

[0055] NCS Networked Control System

[0056] 5GS 5G System

[0057] XRM Extended Reality and Media

[0058] PDU Protocol Data Unit

[0059] RLC Radio Link Control

[0060] RRC Radio Resource Control

[0061] QoS Quality of Service

[0062] SDU Service Data Unit

[0063] RAN Radio Access Network

[0064] QFI QoS Flow Identifier gNB gNodeB (5G Base Station)

[0065] NAS Non-Access Stratum

[0066] AMF Access and Mobility Management Function

[0067] SMF Session Management Function

[0068] PCF Policy Control Function

[0069] AF Application Function

[0070] DRB Data Radio Bearer

[0071] IE Information Element

[0072] TSC Time Sensitive Communications

[0073] TSCAI TSC Assistance Information

[0074] TSCTSF TSC Time Synchronization Function

[0075] 3GPP 3rd Generation Partnership Project

[0076] AN Access Network

[0077] CN Core Network

[0078] DL Downlink

[0079] UL Uplink

[0080] UE User Equipment

[0081] As already described above, the mobile telecommunication system 100 shown in figure 1 may be based on or comprise a 3GPP mobile telecommunication system 100, for instance a 5G mobile network 100. As will be appreciated, a conventional 5G mobile network does not actively apply differentiated treatment of PDCP PDUs based on their importance. This means, that a conventional 5G mobile network provides only a passive discarding mechanism based on PDU set importance to reduce network congestion time (when it occurs), by dropping less important frames (e.g., B- or P-frames). However, not considering the importance actively (i.e., not only in congestion) leads to an inefficient utilization of the network, computation and energy resources due to the transmission of unimportant and / or outdated information, although they are not useful for the receiver, as further illustrated by the examples shown in figures 2a and 2b.

[0082] Figure 2a illustrates an example of a PDCP PDU (on the transmitter side) that consists of a header 31 and two consecutive measurements 30a, 30b of the same sensor, i.e., sensor data for from a time n and sensor data from a time n-1. However, it is a common assumption in networked control that if a more recent information about a remotely monitored process (e.g., position) is available, the older information becomes obsolete and is simply discarded by the receiving application, thus, wasting communication resources.

[0083] Figure 2b illustrates a further example where a source has some very urgent and / or critical information to send to the destination, e.g., a sensor-to-controller IP packet 30c. As conventionally the importance handling is not done actively, in particular not in the PDCP layer, the important packet 30c will have to wait until the previous PDUs 30a, b are served that are still waiting in the transmission buffer.

[0084] As will be appreciated, for both the examples illustrated in figures 2a and 2b the radio resources have been used inefficiently due to the transmission of either redundant or less important packets. Consequently, in a conventional system the application performance (control performance) may deteriorate and more frequent system failures may occur due to wrong prioritization of packets. In addition, the received information may arrive with high staleness due to the time spent in the transmission queue, i.e., when a control input or sensor measurement arrives at the receiving application, it is already outdated and is not useful and / or inaccurate.

[0085] Embodiments disclosed herein address the issues mentioned above by providing the UE 110 and the base station 120 of figure 1 with a PDCP entity 140 allowing for a differentiated treatment of PDUs among as well as within QoS flows, as illustrated in figures 3a and 3b. More specifically, the UE 110 and the base station 120 are configured to implement a PDCP entity 140, wherein the PDCP entity 140 comprises or operates at least two different transmission buffers 142a, b and wherein the PDCP entity 140 is configured to assign a plurality of packets 130a-d (for instance, SDUs or PDUs 130a-d) associated with one or more data flows to the at least two different transmission buffers 142a, b. In other words, to differentiate among data, e.g. QoS flows (i.e., inter-flow), the PDCP entity 140 of the UE 110 and the base station 120 may maintain a separate transmission buffer 142a, b for each QoS flow. According to an embodiment, the PDCP entity 140 is further configured to separate the SDUs 130a- d of different QoS flows after identifying these by their QFI (as illustrated by the processing block 141 in figure 3a) and subsequently storing these in the corresponding transmission buffer 142a, b. In an embodiment, multiple QoS flows may be mapped to one PDCP entity 140.

[0086] To differentiate the PDUs 130a-d within the same QoS flow (i.e., intra-flow), the PDCP entity 140 according to an embodiment is further configured to actively discard any PDU already stored in the QoS flow’s transmission buffer 142a, b as well as reorder / prioritize them depending on their importance, as illustrated by the embodiment shown in figure 3b, where the PDU 130a is discarded because of the “freshed’ PDU 130c.

[0087] As this type of PDCP entity 140 is useful for certain applications including but not limited to NCSs, the implementation of the PDCP entity 140 described above is not the conventional default configuration. Therefore, according to an embodiment, the UE 110 and the base station 120 may be configured with configuration data to implement the PDCP entity 140 in the way disclosed herein via RRC signaling. According to an embodiment, the conventional RRCReconfiguration message may be modified to select and configure the PDCP entity 140 of the UE 110 and the base station 120, accordingly. In an embodiment, this may be achieved by a new field in the pdcp-Config information element, as will be described in more detail below.

[0088] As will be appreciated, the importance of PDUs 130a-d plays an important role for the operation of the PDCP entity 140 disclosed herein. According to an embodiment, the PDU importance may be marked or indicated, for instance, by an application layer of the UE 110 in a readable form by the PDCP entity 140 or may be communicated to the PDCP entity 140 in an offline manner. In an embodiment this second option may be implemented by a “PDU importance map”, which may be communicated by an application to the mobile network 100. Figure 4a shows a signalling diagram illustrating the configuration of the PDCP entity 140 according to an embodiment. In the embodiment shown in figure 4a the RRCReconfiguration message from the network 150 in step 401 contains the configuration data of the PDCP entity 140. In other words, the RRCReconfiguration message of step 401 contains the configuration data for the UE 110 to implement the PDCP entity 140 according to embodiments described above or below. In step 403 of figure 4a the UE 110 acknowledges the successful completion of an RRC connection reconfiguration in response to the RRCReconfiguration message. Figure 4b shows a more detailed embodiment of the signalling diagram of figure 4a. In figure 4b the RRCReconfiguration message with the configuration data is sent from the base station 120, e.g. gNB 120 to the UE 110. After establishing the data radio bearer in step 402 of figure 4b, the UE 110 acknowledges the successful completion of an RRC connection reconfiguration in response to the RRCReconfiguration message in step 403 of figure 4b.

[0089] As will be appreciated, in the embodiments shown in figures 4a and 4b the relevant part of the RRCReconfiguration message is the pdcp-Config information element (IE) with the following hierarchical structure:

[0090] -> RRCReconfiguration { RadioBearerConfig { drb-ToAddModList { pdcp-Config } } }

[0091] The RadioBearerConfig IE has two relevant IES within: sdap-Config and pdcp-Config.

[0092] The sdap-Config IE contains mappedQoS-FkrwsToAdd field which includes the QFI of the QoS flow. Based on this information a SDAP entity of the UE 110 knows how to map any PDU 130a-d from this QoS flow to this DRB, as a result to the PDCP entity 140 of this DRB.

[0093] The pdcp-Config is the IE containing the configuration information for the PDCP entity 140 of this DRB. Hence, a new field may be added in the pdcp-Config IE called tsc-PDUImportanceHandling, which is a binary variable, i.e., {true, false}, indicating that the PDCP entity 140 should activate differentiated treatment of PDUs 130a-d, as implemented by the embodiments disclosed herein.

[0094] As in an embodiment the PDCP entity 140 is configured to keep a separate transmission buffer 142a, b for each flow served by the PDCP entity 140, each flow may configure the buffer capacity, i.e., BQFI. If the tsc-PDUImportanceHandling is set to true, the default buffer size may be one PDU. However, according to an embodiment the size of the transmission buffers 142a, b of the PDCP entity 140 may be configured in units of PDU per flow by means of a new field in the pdcp-Config provided as tuples of (QFI, BQFI). In an embodiment, the buffer capacity per QoS flow may be defined by an application function (AF) 155 associated with a corresponding application running on the UE 110.

[0095] As already described above, in an embodiment the PDU importance may be marked or indicated in an offline manner based on a “PDU importance map”, which may be communication by an application to the mobile network 100. To this end, as illustrated in the embodiment shown in figure 5, if the application wants to provide an offline importance map, which helps the transmitting PDCP entity 140 to determine the importance of a PDU depending on certain parameters, e.g., timestamp, sequence number, this may be done via the application function (AF) 155 and propagated from the 5G core network 150 to the 5G RAN 105. For downlink UP traffic, the tsc-PDUImportanceMap may be sent from the AMF 151 to the base station 120, e.g. gNB 120 using the NG-AP protocol between the AMF 151 and the gNB 120 over the N2 interface. For uplink UP traffic, in addition to the NG-AP (AMF to gNB), the tsc-PDUImportanceMap may be forwarded to the UE 110 by the base station, e.g. gNB 120. In an embodiment, this data may also be part of the pdcp-Config per QoS flow (similar to the buffer size per QoS flow).

[0096] In the following several options will be described for providing the PDU importance map from the AF 155 to the RAN 105. A first option, i.e. embodiment employs TSCAI UL and TSCAI DL for carrying the tsc-PDUImportanceMap. More specifically, in this embodiment the tsc-PDUImportanceMap is provided by the application via the 5GC 150 to the 5G RAN 105 based on the TSCAI. The TSCAI is providedby the AF 155 for each direction, i.e., UL andDL for the specified QoS flow to the TSCTSF 154. The TSCTSF 154 generates the TSC assistance container that carries the tsc-PDUImportanceMap, which is sent to the SMF 152 via the PCF 153. After the SMF 152 passes the TSCAI as SM related information to the AMF 151, the AMF 151 provides the TSCAI UL and TSCAI DL in the PDU SESSION RESOURCE SETUP REQUEST as a part of the NG-AP protocol both for UL and DL.

[0097] As will be appreciated, the previous option of using the TSCAI is one possible implementation for the distribution of the offline importance map. According to a further option, i.e. embodiment the tsc-PDUImportanceMap may be carried by a new information element between the AF 155 and the PCF 153 different from the TSCAI so that this new information element is not received / forwarded by the TSCTSF 154.

[0098] According to a third option, the tsc-PDUImportanceMap may be generated or modified by a network function within the core network 150, hence, not being received by the application server via the AF 155.

[0099] Figures 6a and 6b show signalling diagrams illustrating how the base station 120 may know that the tsc- PDUImportanceHandling should be activated for a given QoS flow. As the proposed importance handling by the PDCP entity 140 is related to the flow-specific QoS rules, this information may be communicated to the 5GS when the QoS flow is being installed, i.e., when the application makes a PDU session establishment / modification request to add this flow requesting this type of service by the PDCP entity 140. This may be done as a part of the NAS protocol specified in TS 24.501. When the core network 150 accepts this request, the AMF sends a PDU session resource setup request (already in NG-AP protocol specified in TS 38.413) via the N2 interface.

[0100] The PDU session resource setup / modification request (see 601 of figure 6a and 605 of figure 6b) received by the gNB 120 may contain the QFI of the QoS flow to be added and the authorized QoS rule. In an embodiment, an IE within the PDU session resource setup request 601 may contain information allowing the gNB 120 to deduct the necessity of a DRB with this new type of service that requires a PDU importance by the PDCP entity 140. If such a DRB exists, the gNB 120 may map the QFI to this DRB. If such a DRB does not exist, the gNB 120 may establish a new DRB and subsequently map the QFI to the new DRB. In either case, this may be done by the RadioBearerConfig IE via the RRC protocol. The RadioBearerConfig IE refers to the DRB that is being established or modified, hence contains the DRB-identity. As further illustrated in figures 6a and 6b, a respective response 603 and 607 may be send in response to the request 601, 605.

[0101] According to a first option, the mobile network 100 may deduct the establishment of the PDCP entity 140 from the provided 5QI value during the PDU session establishment or modification request. In other words, a new 5QI value, such as “5QI = XY”, may be introduced that corresponds to this type of QoS flow, i.e., a QoS flow that requires a differentiated treatment of PDUs within the same flow according to their importance as implemented by the PDCP entity 140. As an alternative, the provisioning of the tsc-PDUImportanceMap can be the initiator of the RRCReconfiguration with the modified pdcp-Config.

[0102] Figures 7a, 7b, and 7c are schematic diagrams illustrating different types of PDUs supported, for instance, by a 5G mobile network and used by the UE 110 and / or a base station 120 according to an embodiment for marking the importance of data packets. More specifically, figures 7a and 7b illustrate an IPv4 and an IPv6 header format as in an IP -type PDU session, while figure 7c illustrates the relevant part of an Ethernet frame (which contrary to the headers shown in figures 7a and 7b also includes a pay load).

[0103] For IPv4 packets the IPv4 header, as illustrated in figure 7a, is not encrypted so that the PDCP entity 140 may read the 6-bit DSCP field 701 of the IP packets. If the sending application is using this field to indicate the importance of the packets, the PDCP entity 140 may observe a changing DSCP field 701 throughout the flow duration. In case the application is not using the DSCP field 701 but sending IPv4 packets for this QoS flow, the DSCP field 701 would have an identical value between packets so that the PDCP entity 140 would not identify a packet as ‘more important’ than any other as the default behavior.

[0104] If the application is making use of the DSCP field 701, the PDCP entity 140 may place the arriving SDU just after the PDU that has a higher DSCP value within the transmission buffer 142a, b reserved for this QoS flow (QFI). In this way, the PDCP entity 140 may always be serving the most important packets first.

[0105] The same behavior above can be achieved for IPv6 packets, as illustrated in figure 7b, by using the six most-significant bits of the traffic class field 703a, which is the differentiated services field (DS field) used to classify packets. Alternatively, IPv6 packets have the 20-bit long “flow label” field 703b, which may be used in a similar way to mark PDU importance by the sending application.

[0106] If the PDU session is an Ethernet PDU session, the received PDCP SDU has a readable Ethernet header with an optional 802. IQ tag 705, as illustrated in figure 7c. According to an embodiment, the optional 802. IQ tag 705 may be utilized to mark the importance of Ethernet frames. If RTP is used for the traffic, then the extended header of RTP can be used to mark the importance of packets.

[0107] Figure 8 is a flow diagram illustrating a method 800 for operating a user equipment, UE, such as the UE 110 of figure 1, for communication via a base station, such as the base station 120 of figure 1, in a mobile network. The method 800 comprises a step 801 of implementing a PDCP entity 140, wherein the PDCP entity 140 comprises at least two different transmission buffers 142a, b and wherein the PDCP entity 140 is configured to assign a plurality of packets 130a-d associated with at least two different data flows to the at least two different transmission buffers 142a, b.

[0108] The method 800 can be performed by the UE 110 according to an embodiment. Thus, further features of the method 800 result directly from the functionality of the UE 110 as well as the different embodiments thereof described above and below.

[0109] Figure 9 is a flow diagram illustrating a method 900 for operating a base station, such as the base station 120 of figure 1, for communication with a UE 110 in a mobile network 100. The method 900 comprises a step 901 of implementing a PDCP entity 140, wherein the PDCP entity 140 comprises at least two different transmission buffers 142a, b and wherein the PDCP entity 140 is configured to assign a plurality of packets 130a-d associated with one or more data flows to the at least two different transmission buffers 142a,b.

[0110] The method 900 can be performed by the base station 120 according to an embodiment. Thus, further features of the method 900 result directly from the functionality of the base station 120 as well as the different embodiments thereof described above and below.

[0111] The person skilled in the art will understand that the "blocks" ("units") of the various figures (method and apparatus) represent or describe functionalities of embodiments of the present disclosure (rather than necessarily individual "units" in hardware or software) and thus describe equally functions or features of apparatus embodiments as well as method embodiments (unit = step).

[0112] In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the described embodiment of an apparatus is merely exemplary. For example, the unit division is merely a logical function division and may be another division in an actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented by using some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronic, mechanical, or other forms. The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

[0113] In addition, functional units in the embodiments of the disclosure may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units may be integrated into one unit.

Claims

CLAIMS1. A user equipment, UE, (110) for communication via abase station (120) in a mobile network (100), wherein the UE (110) is configured to: implement a Packet Data Convergence Protocol, PDCP, entity (140), wherein the PDCP entity (140) comprises at least two different transmission buffers (142a, b) and wherein the PDCP entity (140) is configured to assign a plurality of packets (130a-d) associated with one or more data flows to the at least two different transmission buffers (142a, b).

2. The UE (110) of claim 1, wherein the UE (110) is configured to implement a protocol stack comprising a PDCP layer (11 lb) and wherein the PDCP entity (140) is implemented in the PDCP layer (11 lb).

3. The UE (110) of claim 1 or 2, wherein each of the plurality of packets (130a-d) comprises a Quality of Service, QoS, Flow Identifier, QFI, and wherein the PDCP entity (140) is configured to assign each of the plurality of packets (130a-d) associated with the one or more data flows to the at least two different transmission buffers ( 142a, b) based on the QFI of each packet (130a-d).

4. The UE (110) of any one of the preceding claims, wherein, when assigning a respective packet (130a-d) to the respective transmission buffer (142a, b), the PDCP entity (140) is configured to discard and / or reorder one or more further packets (130a- d) previously assigned to the transmission buffer (142a, b).

5. The UE (110) of claim 4, wherein the PDCP entity (140) is configured to receive PDCP configuration information and wherein for each of the one or more data flows the PDCP entity (140) is configured to discard and / or reorder the one or more further packets previously assigned to the transmission buffer (142a,b) based on the PDCP configuration information.

6. The UE (110) of claim 4 or 5, wherein the PDCP entity (140) is configured to discard and / or reorder the one or more further packets (13 Oa-d) previously assigned to the transmission buffer ( 142a, b) based on an importance indication associated with each packet (130a-d) of a data flow.

7. The UE (110) of claim 6, wherein the PDCP entity (140) is configured to receive for each packet (130a-d) of the one ormore data flows a IP, RTP, and / or Ethernet header and wherein the PDCP entity (140) is configured to extract the importance indication associated with each packet (130a-d) of a data flow from the IP, RTP, and / or Ethernet header of the packet (130a- d).

8. The UE (110) of claim 6 or 7, wherein the importance indication associated with each packet (130a-d) of a data flow is provided by a UE application associated with the data flow or is based on a packet importance map obtained from an application function (155) of the mobile network (100), wherein the application function (155) is associated with the data flow.

9. The UE (110) of any one of the preceding claims, wherein the UE (110) is configured to receive a RRCReconfiguration message from the base station (120) and to implement the PDCP entity (140) in accordance with information contained in the RRCReconfiguration message.

10. The UE (110) of claim 9, wherein the information is contained in a field of a pdcp-Config information element of the RRCReconfiguration message.

11. A method (800) for operating a user equipment, UE, (110) for communication via a base station (120) in a mobile network (100), wherein the method (800) comprises: implementing (801) a Packet Data Convergence Protocol, PDCP, entity (140), wherein the PDCP entity (140) comprises at least two different transmission buffers (142a, b) and wherein the PDCP entity (140) is configured to assign a plurality of packets (130a-d) associated with at least two different data flows to the at least two different transmission buffers (142a, b).

12. A base station (120) for communication with a user equipment, UE, (110) in a mobile network (100), wherein the base station (120) is configured to: implement a Packet Data Convergence Protocol, PDCP, entity (140), wherein the PDCP entity (140) comprises at least two different transmission buffers (142a, b) and wherein the PDCP entity (140) is configured to assign a plurality of packets (130a-d) associated with one or more data flows to the at least two different transmission buffers (142a, b).

13. The base station (120) of claim 12, wherein the base station (120) is configured to implement a protocol stack comprising a PDCP layer (121b) and wherein the PDCP entity (140) is implemented in the PDCP layer (121b).

14. The base station (120) of claim 12 or 13, wherein each of the plurality of packets (130a-d) comprises a Quality of Service, QoS, Flow Identifier, QFI, and wherein the PDCP entity (140) is configured to assign each of the plurality of packets (13 Oa-d) associated with the one or more data flows to the at least two different transmission buffers ( 142a, b) based on the QFI of each packet (130a-d).

15. The base station (120) of any one of claims 12 to 14, wherein, when assigning a respective packet (130a-d) to the respective transmission buffer (142a, b), the PDCP entity (140) is configured to discard and / or reorder one or more further packets previously assigned to the transmission buffer (142a, b).

16. The base station (120) of claim 15, wherein the PDCP entity (140) is configured to receive PDCP configuration information and wherein for each of the one or more data flows the PDCP entity (140) is configured to discard and / or reorder the one or more further packets previously assigned to the transmission buffer (142a, b) based on the PDCP configuration information.

17. The base station (120) of claim 15 or 16, wherein the PDCP entity (140) is configured to discard and / or reorder the one or more further packets previously assigned to the transmission buffer (142a,b) based on an importance indication associated with each packet (130a-d) of a data flow.

18. The base station (120) of claim 17, wherein the PDCP entity (140) is configured to receive for each packet (130a-d) of the one or more data flows an IP, RTP, and / or Ethernet header and wherein the PDCP entity (140) is configured to extract the importance indication associated with each packet (130a-d) of a data flow from the IP, RTP, and / or Ethernet header of the packet (130a-d).

19. The base station (120) of claim 17 or 18, wherein the importance indication associated with each packet (130a-d) of a data flow is based on a packet importance map obtained from an application function (155) of the mobile network (100), wherein the application function (155) is associated with the data flow.

20. A method (900) for operating a base station (120) for communication with a user equipment, UE, (110) in a mobile network (100), wherein the method (900) comprises: implementing (901) a Packet Data Convergence Protocol, PDCP, entity (140), wherein the PDCP entity (140) comprises at least two different transmission buffers (142a, b) and wherein the PDCP entity (140) is configured to assign a plurality of packets (13 Oa-d) associated with one or more data flows to the at least two different transmission buffers(142a, b).

21. A computer program product comprising a computer-readable storage medium for storing program code which causes a computer or a processor to perform the method (800) of claim 11 or the method (900) of claim 20 when the program code is executed by the computer or the processor.

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