Managing calculations for a delay critical buffer volume

Abstract

A method, system and apparatus are disclosed. A method implemented in a user equipment, UE, configured to communicate with a network node, includes: receiving a configuration for a buffer volume calculation; and reporting, to the network node, a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level.

Description

[0001] MANAGING CALCULATIONS FOR A DELAY CRITICAL BUFFER VOLUME

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to wireless communications, and in particular, to managing delay critical buffer volume.

[0004] BACKGROUND

[0005] The Third Generation Partnership Project (3 GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile user equipments (UE), as well as communication between network nodes and between WDs. The 3 GPP is also developing standards for Sixth Generation (6G) wireless communication networks.

[0006] 5G is the fifth generation of mobile communications, addressing a wide range of use cases from enhanced mobile broadband (eMBB) to ultra-reliable low-latency communications (URLLC) to massive machine type communications (mMTC). 5G includes the New Radio (NR) access stratum interface and the 5G Core Network (5GC). The NR physical and higher layers are reusing parts of the LTE specification, and to that add needed components when motivated by new use cases.

[0007] Low-latency high-rate applications such as extended Reality (XR) and cloud gaming are important in 5G era. XR may refer to all real- and- virtual combined environments and human-machine interactions generated by computer technology and wearables. It is an umbrella term for different types of realities including Virtual reality (VR), Augmented reality (AR), Mixed reality (MR), and the areas interpolated among them. The levels of virtuality range from partially sensory inputs to fully immersive VR.

[0008] Low-latency high-rate XR applications

[0009] The low-latency applications like XR and cloud gaming may require bounded latency, not necessarily ultra-low latency. The end-to-end latency budget may be in the range of 20-80 ms, which may need to be distributed over several components including application processing latency, transport latency, radio link latency, etc. For these applications, short transmission time intervals (TTIs) or mini-slots targeting ultra-low latency may not be effective. FIG. 1 shows an example of frame latency measured over radio access network (RAN), excluding application & core network latencies. The lines in FIG. 1 represent the variation in frame latency over time for three different users (i.e., each line corresponds to a user). With respect to these lines and understanding the significance of the figure, it matters little which user corresponds to which line, only that the lines represent different users. It can be seen that there exist frame latency spikes in RAN. The sources for the latency spikes may include queuing delay, time-varying radio environments, time-varying frame sizes, among others. Tools that can help to remove latency spikes are beneficial to enable better 5G support for this type of traffic.

[0010] The latency spike occurs due to instantaneous shortage of radio resources or inefficient radio resource allocation in response to varying frame size.

[0011] In addition to bounded latency requirements, the applications like XR and cloud gaming may also require high rate transmission. This can be seen from the large frame sizes originated from this type of traffic. The typical frame sizes may range from, e.g., tens of kilobytes to hundreds of kilobytes. The frame arrival rates may be, e.g., 60 or 120 frames per second (fps). As a concrete example, a frame size of 100 kilobytes and a frame arrival rate of 120 fps can lead to a rate requirement of 95.8 Mbps.

[0012] A large video frame may be fragmented into smaller IP packets and transmitted as several transport blocks (TBs) over several TTIs in RAN. FIG. 2 shows an example of the cumulative distribution functions of the number of transport blocks required to deliver a video frame with size ranging from 20 KB to 300 KB. For example, FIG. 2 shows that for delivering the frames with a size of 200 KB each, the median number of needed TBs is 5.

[0013] The characteristics of XR traffic arrival are quite distinct from typical webbrowsing and VoIP traffic as shown in FIG. 3. In FIG. 3, the height (Y axis) of the bars represents the relative size of the data generated for XR, VoIP and Web browsing over time (X-axis), respectively. It may be expected that the arrival time may be quasi-periodic and largely predictable as VoIP. However, its data size may be an order of magnitude larger than VoIP, as discussed above. In addition, similar to web-browsing, the data size may be different at every application PDU arrival instance due to dynamics of contents and human motion.

[0014] As mentioned above, many XR applications may generate traffic periodically with a variable size. When the application packet enters the internet, the initial packet may be transmitted into a single PDU in the network or may be segmented several PDUs. One application packet could, for instance, correspond to one or several IP packets.

[0015] IP packets will arrive to the Packet Data Convergence Protocol (PDCP) layer, i.e., PDCP Service Data Units (SDUs), and the PDCP layer will create PDCP Protocol Data Units (PDUs) and will deliver then to lower layers. When an Internet Protocol (IP) packet arrives to PDCP, the PDCP layer starts a PDCP discard timer. When this timer expires, the PDCP discards the PDCP SDU as well as the corresponding PDCP Data PDU. If the PDCP PDU was delivered to lower layers, PDCP indicates the discard to lower layers. Lower layers, e.g., Radio Link Control (RLC) will discard the PDCP PDUs (RLC SDU) if these RLC SDU or any segment of the RLC SDU has not yet been transmitted to lower layers.

[0016] As discussed above, an application PDU, e.g., a video frame, is divided into multiple IP packets. All these IP packets which belong to one video frame can be defined as PDU Set.

[0017] 3 GPP Rel-18 agreements on XR features

[0018] In, e.g., 3GPP Technical Specification Group Service and System Aspects (TSG SA) Work Group 2 (WG2) (SA2) it has been identified that PDU sets could be assigned with a PDU Set Importance indicator. This parameter can be used to identify the importance of a PDU Set within a QoS flow. RAN may use it for PDU Set level packet discarding in presence of congestion.

[0019] PDU Set has been defined by, e.g., 3GPP Technical Reference (TR) 23.700-60. A PDU Set may be composed of one or more PDUs carrying the payload of one unit of information generated at the application level (e.g., a frame or video slice for XRM Services, as used in, e.g., 3GPP TR 26.926). In some implementations, all PDUs in a PDU Set may be needed by the application layer to use the corresponding unit of information. In other implementations, the application layer can still recover parts all or of the information unit when some PDUs are missing.

[0020] 3GPP has agreed on having a “PDU Set Importance” (PSI) indicator which indicates a certain importance level for the said PDU Set. The importance level of the PDU Sets indicates how useful the PDU Set is for the application, the assumption is that low importance PDU Sets can be down prioritized, or even discarded, in favor of more reliable delivery of higher importance PDU Sets. In 3 GPP Release 18 (Rell8) XR Work Item (WI), new solutions for Uplink (UL) Public Service Identity (PSI) based discarding was introduced. The solution introduced is completely depending the UE to do the identification of the PSI levels of the PDU Sets, and it determines what is a low or high importance PDU Set, and then applies the behavior configured by the network on each of the PDU Set depending on their identified importance. No information about the PDU Sets is delivered to the network.

[0021] Furthermore, a new delay and buffer reporting enhancements were introduced in Rel-18: Delay Status Reporting (DSR). The DSR is a new Medium Access Control Control Element (MAC CE), with separate handling from the legacy Buffer Status Report (BSR). The format for the DSR is as shown in FIG. 4.

[0022] The fields in the DSR MAC CE are defined as follows:

[0023] LCGi: This field indicates the presence of delay information (i.e., the Remaining Time and Buffer Size fields) for the LCG i. The LCGi field set to 1 indicates that the delay information for the LCG i is reported. The LCGi field set to 0 indicates that the delay information for the LCG i is not reported;

[0024] Remaining Time: This field indicates the shortest remaining value of PDCP discardTimer (described in, e.g., clause 7.3 in 3GPP Technical Specification (TS) 38.323) among all PDCP SDUs buffered for an LCG, at the time of the first symbol of the first PUSCH transmission that includes this DSR MAC CE. The length of this field is 6 bits. The value r in this field indicates a remaining time within the range of (r, r + 1] msec.

[0025] BT: This field is present only if the corresponding LCG is configured with cidditioncdBSR-Table Allowed otherwise, this field is reserved. If present, the BT field set to 1 indicates that the buffer sizes specified in Table 6.1.3.1-x (from the 3GPP TS) are used to set the value of the Buffer Size field, while the BT field set to 0 indicates that the buffer sizes specified in Table 6.1.3.1-2 (from the 3GPP TS) are used instead.

[0026] Buffer Size: The Buffer Size field indicates the total amount of delay- critical UL data for an LCG according to the data volume calculation procedure specified in, e.g., clause 5.5 in 3GPP TS 38.322 and clause 5.6 in 3GPP TS 38.323 for the associated RLC and PDCP entities, respectively, after the MAC PDU has been built. If the corresponding LCG is configured with additionalBSR-TableAllowed and the amount of delay-critical UL data for an LCG is within the buffer sizes specified in Table 6.1.3.1-x, the MAC entity shall use the buffer sizes specified in Table 6.1.3.1-x to set the value of this field; otherwise, the MAC entity shall use Table 6.1.3.1-2 instead. This field is indicated in number of bytes. The length of this field is 8 bits.

[0027] The Remaining Time, the BT, and the Buffer Size fields for an LCG may be reported in two consecutive octets. These three fields for different LCGs may be included in a DSR MAC CE in ascending order based on theLCGi.

[0028] For the purpose of the delay critical buffer volume reporting in the DSR, the delay criticial PDCP SDU is specified by, e.g., 3GPP Change Request (CR) R2-2313697 as the following:

[0029] Delay-critical PDCP SDU: if pdu-SetDiscard is not configured, a PDCP SDU for which the remaining time till discardTimer expiry is less than the remainingTimeThreshold. If pdu-SetDiscard is configured, a PDCP SDU belonging to a PDU Set of which at least one PDCP SDU has the remaining time till discardTimer expiry less than the remainingTimeThreshold.

[0030] When a UE reports a DSR while simultaneously is configured to discard “low Importance” PDU Sets when the “discardTimerForLowImportance” expires, the buffer volume calculation for “delay critical data” does not include the data volume of the low importance PDU Sets. This poses a problem for the network node scheduler when deciding the size of the grant. For example, a UE may have 8000 bytes of delay critical data and 2000 bytes of low importance data. Suppose also that the low importance PDU Set data arrived before the delay critical data. When the UE reports a DSR, the buffer size field will indicate 8000 bytes. In this situation the network node will lack knowledge of the buffer volume of the un-important data, i.e., it doesn’t know how much low importance data is in the buffer nor does it know that this data is first in queue to be scheduled. In this situation the network node may schedule a grant for the 8000 bytes of delay critical data, however the UE will fill the grant with 2000 bytes of low important data and 6000 bytes of delay critical data. In this situation the scheduling is sub-optimal, since it is un-intentionally prioritizes low importance data.

[0031] A related problem is that the ‘remaining time’ field reported in the DSR is only based on the legacy discardTimer value. If low importance data is included in the delay critical data reported in the DSR, the reported remaining time may be misleading and solutions for this may warranted. SUMMARY

[0032] Some embodiments advantageously provide methods, systems, and apparatuses for managing delay critical buffer volume.

[0033] Described herein are solutions to address the reported delay critical data problem, including:

[0034] • Introduce new rules and definitions regarding what constitutes delay critical data when low PSI discarding is configured.

[0035] • Introduce network control of when low PSI data is included in the delay critical data volume calculation.

[0036] • Introduce functionality of the R-bit in the DSR format.

[0037] When reported delay critical data includes low importance data solutions for how to calculate the related remaining time is also described in some embodiments.

[0038] In some embodiments:

[0039] • The definition of “delay critical data” is re-defined to also include the low Importance data volume when “discardTimerForLowImportance” is configured.

[0040] • PSI PDU Set may always be first in queue when data is selected to fill the UL grant.

[0041] • The ability for the network to configure a UE is introduced, including whether to also include low Importance data volume in the DSR buffer volume calculation when “discardTimerForLowImportance” is configured.

[0042] • R-bit in DSR can be used to indicate the inclusion of low importance bits and low importance bits is first in queue.

[0043] • R-bit signals that high importance are first in queue

[0044] • If Low PSI is first in queue, then low PSI data volume may be included in the delay critical data volume calculation.

[0045] In some embodiments, when data with low importance / PSI is included in the delay critical data reported in the DSR, the remaining time may be adjusted according to different options:

[0046] • When data with low importance / PSI levels is included in the DSR buffer volume calculation, the ‘discardTimerForLowImportance’ is also considered when determining the ‘remaining time’ field. • Make it possible for network to configure whether ‘discardTimerForLowImportance’ should be considered when determining the ‘remaining time’ field.

[0047] • Add conditions when the ‘discardTimerForLowImportance’ should be considered when determining the ‘remaining time’ field, e.g., only when a PDU Set with low importance / PSI levels are first in the queue.

[0048] • Add reporting in the DSR which timer the remaining time value is based on.

[0049] According to one aspect of the present disclosure, a method implemented in a UE configured to communicate with a network node is provided. The method comprises: receiving a configuration for a buffer volume calculation; and reporting, to the network node, a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level.

[0050] According to one or more embodiments of this aspect, the method further comprises receiving an uplink, UL, grant from the network node in response to the reporting of the size of the buffer volume.

[0051] According to one or more embodiments of this aspect, the first priority level is associated with a first Protocol Data Unit Set Importance, PSI, value and the second priority level is associated with a second PSI value lower than the first PSI value.

[0052] According to one or more embodiments of this aspect, the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a next uplink, UL, grant.

[0053] According to one or more embodiments of this aspect, the second data is associated with a discard timer.

[0054] According to one or more embodiments of this aspect: the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer.

[0055] According to another aspect of the present disclosure, a user equipment configured to communicate with a network node is provided. UE is configured to: receive a configuration for a buffer volume calculation; and report, to the network node, a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level.

[0056] According to one or more embodiments of this aspect, the UE is further configured to receive a UL grant from the network node in response to the reporting of the size of the buffer volume.

[0057] According to one or more embodiments of this aspect, the first priority level is associated with a first PSI value and the second priority level is associated with a second PSI value lower than the first PSI value.

[0058] According to one or more embodiments of this aspect, the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a UL grant.

[0059] According to one or more embodiments of this aspect, the second data is associated with a discard timer.

[0060] According to one or more embodiments of this aspect, the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer.

[0061] According to another aspect of the present disclosure, a method implemented in a network node configured to communicate with a UE is provided. The method comprises: determining a configuration for a buffer volume calculation; and transmitting the configuration for the buffer volume calculation, the configuration for the buffer volume calculation being configured to cause the UE to report a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level.

[0062] According to one or more embodiments of this aspect, the method further comprises configuring the UE with a UL grant in response to the reporting of the size of the buffer volume.

[0063] According to one or more embodiments of this aspect, the first priority level is associated with a first PSI value and the second priority level is associated with a second PSI value lower than the first PSI value. According to one or more embodiments of this aspect, the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a next UL grant.

[0064] According to one or more embodiments of this aspect, the second data is associated with a discard timer.

[0065] According to one or more embodiments of this aspect: the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer.

[0066] According to another aspect of the present disclosure, a network node configured to communicate with a UE is provided. The network node is configured to: determine a configuration for a buffer volume calculation; and transmit the configuration for the buffer volume calculation, the configuration for the buffer volume calculation being configured to cause the UE to report a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level.

[0067] According to one or more embodiments of this aspect, the network node is further configured to configure the UE with a UL grant in response to the reporting of the size of the buffer volume.

[0068] According to one or more embodiments of this aspect, the first priority level is associated with a first PSI value and the second priority level is associated with a second PSI value lower than the first PSI value.

[0069] According to one or more embodiments of this aspect, the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a next UL grant.

[0070] According to one or more embodiments of this aspect, the second data is associated with a discard timer.

[0071] According to one or more embodiments of this aspect, the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

[0073] FIG. 1 is a graph of an example of frame latency measured over RAN (excluding application and CN latencies);

[0074] FIG. 2 is a graph of an example of the cumulative distribution functions of the number of transport blocks required to deliver a video frame with size ranging from 20 KB to 300 KB;

[0075] FIG. 3 is a graph of XR traffic characteristics compared to VoIP and Webbrowsing;

[0076] FIG. 4 is a diagram of a format for DSR;

[0077] FIG. 5 is a schematic diagram of an example network architecture illustrating a communication system according to the principles in the present disclosure;

[0078] FIG. 6 is a block diagram of a network node in communication with with a user equipment over an at least partially wireless connection according to some embodiments of the present disclosure;

[0079] FIG. 7 is a flowchart of an example process in a network node according to some embodiments of the present disclosure;

[0080] FIG. 8 is a flowchart of an example process in a user equipment according to some embodiments of the present disclosure;

[0081] FIG. 9 is another flowchart of another example process in a network node according to some embodiments of the present disclosure; and

[0082] FIG. 10 is another flowchart of another example process in a user equipment according to some embodiments of the present disclosure.

[0083] DETAILED DESCRIPTION

[0084] Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to managing delay critical buffer volume. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.

[0085] As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0086] In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

[0087] In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and / or wireless connections.

[0088] The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multistandard radio (MSR) radio node such as MSR BS, multi-cell / multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a user equipment (UE) such as a wireless device (WD) or a radio network node.

[0089] In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The UE herein can be any type of wireless device capable of communicating with a network node or another UE over radio signals, such as a wireless device (WD). The UE may also be a radio communication device, target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine communication (M2M), low-cost and / or low-complexity UE, a sensor equipped with UE, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (loT) device, or a Narrowband loT (NB-IOT) device, etc.

[0090] Also, in some embodiments the generic term “radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell / multicast Coordination Entity (MCE), IAB node, relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

[0091] Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and / or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

[0092] In some embodiments, the general description elements in the form of “one of A and B” corresponds to A or B. In some embodiments, at least one of A and B corresponds to A, B or AB, or to one or more of A and B, or one or both of A and B . In some embodiments, at least one of A, B and C corresponds to one or more of A, B and C, and / or A, B, C or a combination thereof. Note further, that functions described herein as being performed by a user equipment or a network node may be distributed over a plurality of user equipments and / or network nodes. In other words, it is contemplated that the functions of the network node and user equipment described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

[0093] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0094] Some embodiments provide for managing delay critical buffer volume.

[0095] Referring again to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 5 a schematic diagram of a communication system 10, according to an embodiment, such as a 3GPP-type cellular network that may support standards such as LTE and / or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first user equipment (UE) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second UE 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of UEs 22a, 22b (collectively referred to as user equipments 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding network node 16. Note that although only two UEs 22 and three network nodes 16 are shown for convenience, the communication system may include many more UEs 22 and network nodes 16.

[0096] Also, it is contemplated that a UE 22 can be in simultaneous communication and / or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a UE 22 can have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, UE 22 can be in communication with an eNB for LTE / E-UTRAN and a gNB for NR / NG-RAN.

[0097] A network node 16 is configured to include a configuration unit 32, which is configured to perform one or more network node 16 functions described herein, including functions related to managing delay critical buffer volume. A user equipment 22 is configured to include a reporting unit 34, which is configured to perform one or more user equipment 22 functions described herein, including functions related to managing delay critical buffer volume.

[0098] Example implementations, in accordance with an embodiment, of the UE 22 and network node 16 will now be described with reference to FIG. 6.

[0099] The communication system 10 includes a network node 16 provided in a communication system 10 and including hardware 58 enabling it to communicate with the UE 22. The hardware 58 may include a communication interface 60 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 10, as well as a radio interface 62 for setting up and maintaining at least a wireless connection 64 with a UE 22 located in a coverage area 18 served by the network node 16. The radio interface 62 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers.

[0100] In the embodiment shown, the hardware 58 of the network node 16 further includes processing circuitry 68. The processing circuitry 68 may include a processor 70 and a memory 72. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 68 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 70 may be configured to access (e.g., write to and / or read from) the memory 72, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0101] Thus, the network node 16 further has software 74 stored internally in, for example, memory 72, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 74 may be executable by the processing circuitry 68. The processing circuitry 68 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by network node 16. Processor 70 corresponds to one or more processors 70 for performing network node 16 functions described herein. The memory 72 is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 74 may include instructions that, when executed by the processor 70 and / or processing circuitry 68, causes the processor 70 and / or processing circuitry 68 to perform the processes described herein with respect to network node 16. For example, processing circuitry 68 of the network node 16 may include configuration unit 32 configured to perform one or more network node 16 functions described herein, including functions related to managing delay critical buffer volume.

[0102] The communication system 10 further includes the UE 22 already referred to. The UE 22 may have hardware 80 that may include a radio interface 82 configured to set up and maintain a wireless connection 64 with a network node 16 serving a coverage area 18 in which the UE 22 is currently located. The radio interface 82 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers.

[0103] The hardware 80 of the UE 22 further includes processing circuitry 84. The processing circuitry 84 may include a processor 86 and memory 88. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 84 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 86 may be configured to access (e.g., write to and / or read from) memory 88, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0104] Thus, the UE 22 may further comprise software 90, which is stored in, for example, memory 88 at the UE 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the UE 22. The software 90 may be executable by the processing circuitry 84. The software 90 may include a client application 92. The client application 92 may be operable to provide a service to a human or non-human user via the UE 22. The client application 92 may interact with the user to generate the user data that it provides.

[0105] The processing circuitry 84 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by UE 22. The processor 86 corresponds to one or more processors 86 for performing UE 22 functions described herein. The UE 22 includes memory 88 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 90 and / or the client application 92 may include instructions that, when executed by the processor 86 and / or processing circuitry 84, causes the processor 86 and / or processing circuitry 84 to perform the processes described herein with respect to UE 22. For example, the processing circuitry 84 of the user equipment 22 may include a reporting unit 34 configured to perform one or more UE 22 functions described herein, including functions related to managing delay critical buffer volume.

[0106] In some embodiments, the inner workings of the network node 16 and UE 22 may be as shown in FIG. 6 and independently, the surrounding network topology may be that of FIG. 5.

[0107] In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve.

[0108] Although FIGS. 5 and 6 show various “units” such as configuration unit 32, and reporting unit 34 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

[0109] FIG. 7 is a flowchart of an example process in a network node 16 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of network node 16 such as by one or more of processing circuitry 68 (including the configuration unit 32), processor 70, radio interface 62 and / or communication interface 60. Network node 16 is configured to determine (Block S 116) a configuration for a buffer volume calculation, the configuration indicating whether to include Protocol Data Unit Set Importance, PSI, data in the buffer volume calculation. Network node 16 is configured to configure (Block SI 18) the UE 22 based on the determined configuration.

[0110] In some embodiments, the configuration includes an indication of whether to include the PSI data in a calculation of delay critical data.

[0111] In some embodiments, the configuration includes an indication of which of a plurality of timers to use in a Delay Status Reporting, DSR, report.

[0112] FIG. 8 is a flowchart of an example process in a user equipment 22 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of user equipment 22 such as by one or more of processing circuitry 84 (including the reporting unit 34), processor 86, radio interface 82 and / or communication interface 60. User equipment 22 is configured to receive (Block S120) a configuration for a buffer volume calculation, the configuration indicating whether to include Protocol Data Unit Set Importance, PSI, data in the buffer volume calculation. User equipment 22 is configured to communicate (Block S122) with the network node based on the determined configuration.

[0113] In some embodiments, the configuration includes an indication of whether to include the PSI data in a calculation of delay critical data.

[0114] In some embodiments, the configuration includes an indication of which of a plurality of timers to use in a Delay Status Reporting, DSR, report.

[0115] FIG. 9 is a flowchart of another example process in a network node 16 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of network node 16 such as by one or more of processing circuitry 68 (including the configuration unit 32), processor 70, radio interface 62 and / or communication interface 60. Network node 16 is configured to determine a configuration for a buffer volume calculation (Block S124). Network node 16 is configured to transmit the configuration for the buffer volume calculation, the configuration for the buffer volume calculation being configured to cause the UE 22 to report a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level (Block S126).

[0116] In some embodiments, the network node 16 is further configured to configure the UE 22 with a UL grant in response to the reporting of the size of the buffer volume. In some embodiments, the first priority level is associated with a first PSI value and the second priority level is associated with a second PSI value lower than the first PSI value.

[0117] In some embodiments, the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a next UL grant.

[0118] In some embodiments, the second data is associated with a discard timer.

[0119] In some embodiments, the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer.

[0120] FIG. 10 is a flowchart of another example process in a user equipment 22 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of user equipment 22 such as by one or more of processing circuitry 84 (including the reporting unit 34), processor 86, radio interface 82 and / or communication interface 60. User equipment 22 is configured to receive a configuration for a buffer volume calculation (Block S128). UE is configured to report, to the network node 16, a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level (Block S130).

[0121] In some embodiments, the UE 22 is further configured to receive a UL grant from the network node 16 in response to the reporting of the size of the buffer volume.

[0122] In some embodiments, the first priority level is associated with a first PSI value and the second priority level is associated with a second PSI value lower than the first PSI value.

[0123] In some embodiments, the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a UL grant.

[0124] In some embodiments, the second data is associated with a discard timer.

[0125] In some embodiments, the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer. In some embodiments, the UE 22 is further configured to receive a UL grant from the network node 16 in response to the reporting of the size of the buffer volume.

[0126] In some embodiments, the first priority level is associated with a first PSI value and the second priority level is associated with a second PSI value lower than the first PSI value.

[0127] In some embodiments, the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a UL grant.

[0128] In some embodiments, the second data is associated with a discard timer.

[0129] In some embodiments, the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer.

[0130] Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for managing delay critical buffer volume. One or more UE 22 functions described below may be performed by one or more of processing circuitry 84, processor 86, reporting unit 34, etc. One or more network node 16 functions described below may be performed by one or more of processing circuitry 68, processor 70, configuration unit 32, etc.

[0131] In an example embodiment, a solution to the problems described above is to only allow the low PSI data in the buffer volume calculation for delay-critical data when the Low PSI data is first in the queue in any of the logical channel(s) that is expected to be scheduled on the next UL grant. This way the network node 16 scheduler can confidently assign a grant in the size of the delay critical data understanding that all delay-critical data, regardless of whether it includes low PSI data, will be scheduled.

[0132] In another embodiment, the definition for delay-critical data can be updated to also account for Low PSI data. For example, the following definition can be used:

[0133] Delay-critical PDCP SDU: if pdu-SetDiscard is not configured, a PDCP SDU for which the remaining time till discardTimer or discardTimerForLowImportance, expiry is less than the remainingTimeThreshold. If pdu-SetDiscard is configured, a PDCP SDU belonging to a PDU Set of which at least one PDCP SDU has the remaining time till discardTimer or discardTimerForLowImportance expiry less than the remainingTimeThreshold.

[0134] With such definition in place, the reported buffer volume of delay critical data may always include low PSI data when discardTimerForLowImportance is configured.

[0135] In yet another embodiment, the network may configure the UE 22 to either include low PSI data in the delay-critical buffer volume calculation or exclude the low PSI data. When low PSI data is included, it would follow the definition as described above.

[0136] In another embodiment, the R-bit in the DSR can be used to take on various meanings to inform the network when the R-bit is set. A few examples are listed below:

[0137] • The R-bit indicated there is low PSI data first in queue.

[0138] • The R-bit indicates that delay-critical data is first in queue.

[0139] • The R-bit indicates only high PSI data is included in the delay-critical buffer volume calculation or only low PSI data is included.

[0140] • The R-bit indicates only high PSI data is included in the delay-critical buffer volume calculation but there is more data which associated discard timer is below the remainingTimeThreshold.

[0141] • The R-bit indicates the buffer report includes all PDCP PDUs regardless of their PSI which associated discard timer expiration value is below the remainingTimeThreshold.

[0142] • The R-bit indicated whether the relative volume of low-importance data and delay critical data exceeds a threshold. E.g. the R-bit is set to 1 if low importance data is above X% of delay critical data volume.

[0143] When any of above methods allowing low importance data to be included in the buffer volume calculation is applied, the UE 22 may also report remaining time related to a PDU belonging to a PDU set with low importance data especially when the low importance data is first in the queue. This would allow a network (e.g., via a network node 16) to decide the best timing to allocate resource considering the urgency of both low and high importance data. One way, in some embodiments, is changing the definition of remaining time considering PDCP discardTimerForLowImportance. An example of new definition of remaining time when discardTimerForLowImportance is configured can be:

[0144] Remaining Time: This field indicates the shortest remaining value of PDCP discardTimer or PDCP discardTimerForLowImportance (described in, e.g., clause 7.3 of 3GPP TS 38.323) among all PDCP SDUs buffered for an LCG, at the time of the first symbol of the first PUSCH transmission that includes this DSR MAC CE. The length of this field may be, e.g., 6 bits. The value r in this field indicates a remaining time within the range of (r, r + 1] msec.

[0145] In an example scenario, where the delay critical data volume also includes Tow importance data,’ it can be up to network configuration to decide if one timer or both timers are to be considered when updating the ‘remaining time’ field in the DSR. If both timers are considered, then the ‘remaining time’ could take on the shortest value of the two.

[0146] In another embodiment, further conditions could be applied by the network (e.g., via a network node 16) as to when to apply different timers. In one such example, the network could configure the UE 22 to only use the ‘discardTimerForLowImportance’ in the ‘remaining time’ field when low importance data is first in the buffer queue, i.e., no data of higher importance data will be transmitted before the low importance data. The selection of timer for reporting could also be depending on the UL scheduling method used (e.g., Logical Channel Prioritization (LCP) mechanism), so that if the UL scheduling is using PSI in the scheduling decision and high importance data may be transmitted first (independent on the packets placing in the buffer queue) the remaining time may be calculated based on the corresponding discard timer of the first to be transmitted packets.

[0147] In yet another embodiment, the DSR is updated with an indication of which timer is used. This could be coupled to the R-bit so that instead of the R bit being used for reporting the inclusion of low importance data in the delay critical data the R bit indicates which timer is used. The decision of which timer to be used can still be depending on configured conditions, e.g., which place the low importance data has in the buffer queue. Example Embodiments:

[0148] Example AL A network node 16 configured to communicate with a user equipment (UE) 22, the network node 16 configured to, and / or comprising a radio interface and / or comprising processing circuitry configured to: determine a configuration for a buffer volume calculation, the configuration indicating whether to include Protocol Data Unit Set Importance, PSI, data in the buffer volume calculation; and configure the UE 22 based on the determined configuration.

[0149] Example A2. The network node 16 of Example Al, wherein the configuration includes an indication of whether to include the PSI data in a calculation of delay critical data. Example A3. The network node 16 of Example Al, wherein the configuration includes an indication of which of a plurality of timers to use in a Delay Status Reporting, DSR, report.

[0150] Example Bl. A method implemented in a network node 16, the method comprising: determining a configuration for a buffer volume calculation, the configuration indicating whether to include Protocol Data Unit Set Importance, PSI, data in the buffer volume calculation; and configuring the UE 22 based on the determined configuration.

[0151] Example B2. The method of Example Bl, wherein the configuration includes an indication of whether to include the PSI data in a calculation of delay critical data.

[0152] Example B3. The method of Example Bl, wherein the configuration includes an indication of which of a plurality of timers to use in a Delay Status Reporting, DSR, report.

[0153] Example Cl. A user equipment (UE) 22 configured to communicate with a network node 16, the UE 22 configured to, and / or comprising a radio interface and / or processing circuitry configured to: receive a configuration for a buffer volume calculation, the configuration indicating whether to include Protocol Data Unit Set Importance, PSI, data in the buffer volume calculation; and communicate with the network node 16 based on the determined configuration.

[0154] Example C2. The UE 22 of Example Cl, wherein the configuration includes an indication of whether to include the PSI data in a calculation of delay critical data.

[0155] Example C3. The UE 22 of Example Cl, wherein the configuration includes an indication of which of a plurality of timers to use in a Delay Status Reporting, DSR, report.

[0156] Example DI. A method implemented in a user equipment (UE) 22, the method comprising: receiving a configuration for a buffer volume calculation, the configuration indicating whether to include Protocol Data Unit Set Importance, PSI, data in the buffer volume calculation; and communicating with the network node 16 based on the determined configuration.

[0157] Example D2. The method of Example DI, wherein the configuration includes an indication of whether to include the PSI data in a calculation of delay critical data.

[0158] Example D3. The method of Example DI, wherein the configuration includes an indication of which of a plurality of timers to use in a Delay Status Reporting, DSR, report. As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and / or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and / or functionality described herein may be performed by, and / or associated to, a corresponding module, which may be implemented in software and / or firmware and / or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

[0159] Some embodiments are described herein with reference to flowchart illustrations and / or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0160] These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0161] The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0162] It is to be understood that the functions / acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality / acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

[0163] Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0164] Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and / or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

[0165] Abbreviations that may be used in the preceding description include:

[0166] Abbreviation Explanation

[0167] BSR Buffer Status Report DRB Data Radio Bearer

[0168] DSR Delay Status Reporting

[0169] IP Internet Protocol

[0170] LCG Logical Channel Group

[0171] LCH Logical Channel

[0172] MAC CE Medium Access Control Control Element

[0173] MAC CE MAC Control Element

[0174] PDCP Packet Data Convergence Protocol

[0175] PDU Protocol Data Unit

[0176] PSI PDU Set Importance

[0177] QoS Quality of Service

[0178] RLC Radio Link Control

[0179] SDU Service Data Unit

[0180] UE User Equipment

[0181] It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

What is claimed is:

1. A method implemented in a user equipment, UE, (22) configured to communicate with a network node (16), the method comprising: receiving (S128) a configuration for a buffer volume calculation; and reporting (S130), to the network node (16), a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level.

2. The method of Claim 1, further comprising receiving an uplink, UL, grant from the network node (16) in response to the reporting of the size of the buffer volume.

3. The method of any one of Claims 1-2, wherein the first priority level is associated with a first Protocol Data Unit Set Importance, PSI, value and the second priority level is associated with a second PSI value lower than the first PSI value.

4. The method of any one of Claims 1-3, wherein the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a next uplink, UL, grant.

5. The method of any one of Claims 1-4, wherein the second data is associated with a discard timer.

6. The method of any one of Claims 1-5, wherein: the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer.

7. A user equipment, UE, (22) configured to communicate with a network node (16), the UE (22) comprising processing circuitry configured to: receive a configuration for a buffer volume calculation; andreport, to the network node (16), a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level.

8. The UE (22) of Claim 7, wherein the processing circuitry is further configured to receive an uplink, UL, grant from the network node (16) in response to the reporting of the size of the buffer volume.

9. The UE (22) of any one of Claims 7-8, wherein the first priority level is associated with a first Protocol Data Unit Set Importance, PSI, value and the second priority level is associated with a second PSI value lower than the first PSI value.

10. The UE (22) of any one of Claims 7-9, wherein the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a next uplink, UL, grant.

11. The UE (22) of any one of Claims 7-10, wherein the second data is associated with a discard timer.

12. The UE (22) of any one of Claims 7-11, wherein: the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer.

13. A method implemented in a network node (16) configured to communicate with a user equipment, UE, (22) the method comprising: determining (S124) a configuration for a buffer volume calculation; and transmitting (S126) the configuration for the buffer volume calculation, the configuration for the buffer volume calculation being configured to cause the UE (22) to report a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size ofsecond data having a second priority level, the second priority level being lower than the first priority level.

14. The method of Claim 13, further comprising configuring the UE (22) with an uplink, UL, grant in response to the reporting of the size of the buffer volume.

15. The method of any one of Claims 13-14, wherein the first priority level is associated with a first Protocol Data Unit Set Importance, PSI, value and the second priority level is associated with a second PSI value lower than the first PSI value.

16. The method of any one of Claims 13-15, wherein the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a next uplink, UL, grant.

17. The method of any one of Claims 13-16, wherein the second data is associated with a discard timer.

18. The method of any one of Claims 13-17, wherein: the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer.

19. A network node (16) configured to communicate with a user equipment, UE, (22) the network node (16) comprising processing circuitry configured to: determine a configuration for a buffer volume calculation; and transmit the configuration for the buffer volume calculation, the configuration for the buffer volume calculation being configured to cause the UE (22) to report a size of the buffer volume, the size of the buffer volume being calculated based on the configuration, a first size of first data having a first priority level, and a second size of second data having a second priority level, the second priority level being lower than the first priority level.

20. The network node (16) of Claim 19, wherein the processing circuitry is further configured to configure the UE (22) with an uplink, UL, grant in response to the reporting of the size of the buffer volume.

21. The network node (16) of any one of Claims 19-20, wherein the first priority level is associated with a first Protocol Data Unit Set Importance, PSI, value and the second priority level is associated with a second PSI value lower than the first PSI value.

22. The network node (16) of any one of Claims 19-21, wherein the second size of the second data is included in the size of the buffer volume when the second data is first in a queue of at least one logical channel expected to be scheduled on a next uplink, UL, grant.

23. The network node (16) of any one of Claims 19-22, wherein the second data is associated with a discard timer.

24. The network node (16) of any one of Claims 19-23, wherein: the first data is associated with a first timer, the second data is associated with a second timer; and the buffer volume is associated with a remaining time, the remaining time being based on one or both of the first timer and the second timer.

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