Facilitating application performance observability in a radio access network

Abstract

Embodiments include methods for a transmitting node configured to operate in a radio access network (RAN). Such methods include receiving a plurality of sets of protocol data units (PDUs) generated by an application and transmitting the plurality of sets of PDUs to a receiving node in the RAN. Such methods include sending, to the receiving node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application. The application observability information is based on at least one of the following determined by the transmitting node for each PDU set: a first time, T1, when a first-received PDU of the PDU set was received by the transmitting node from the application; and a second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

Description

[0001] FACILITATING APPLICATION PERFORMANCE OBSERVABILITY IN A RADIO ACCESS NETWORK TECHNICAL FIELD

[0002] The present disclosure relates generally to wireless networks, and more specifically to techniques for monitoring whether data communications between nodes in a radio access network (RAN) meets performance requirements of an application that generates the data.

[0003] BACKGROUND

[0004] The fifth generation (5G) of cellular mobile systems - also referred to as New Radio (NR) - is being standardized within the Third-Generation Partnership Project (3 GPP). 5G / NR is developed for maximum flexibility to support multiple and substantially different use cases. These include enhanced mobile broadband (eMBB), machine type communications (MTC), ultra-reliable low latency communications (URLLC), side-link device-to-device (D2D), and several other use cases. 5G / NR was introduced in 3GPP Release 15 (Rel-15) and continues to evolve through subsequent releases.

[0005] In the context of communication protocol layers, the term “service data unit” (or SDU) refers to a unit of data that a protocol layer receives from a next-higher layer in the protocol stack. In contrast, the term “protocol data unit” (or PDU) refers to a unit of data that a protocol layer generates and sends to a next-lower layer in the protocol stack. In other words, a PDU generated by layer N may be identical to an SDU of layer N-l. Given this relationship, the terms PDU and SDU may be used interchangeably in the following disclosure, but the above distinctions should be kept in mind.

[0006] 5G and early-generation mobile systems generally have carried data traffic on a “best effort” basis, even though each generation has included various quality-of-service (QoS) solutions intended to provide differentiated and / or prioritized handling of various data traffic. While such solutions provide certain level of data traffic differentiation, their overall efficacy is questionable. Many data applications or services generate PDUs / SDUs that are larger than a size of a single Internet Protocol (IP) packet. This requires an application PDU to be segmented into multiple IP packets for transmission, which may even traverse different paths in the network.

[0007] In some cases, multiple IP packets that contain a single PDU may be carried over specific network slices and may get differentiated treatment compared to other traffic. However, this handling is typically based on individual IP packets and not the underlying application PDU, because mobile networks conventionally are unable to identify and mark application PDUs for differentiated QoS handling. Instead, mobile networks make independent handling decisions for individual IP packets, as well as monitoring and observing individual IP packets.Extended Reality (XR) and cloud gaming are important media applications for 5G and subsequent-generation networks. XR is an umbrella term that refers to all real-and-virtual combined environments and human-machine interactions generated by computer technology and wearables. It includes exemplary forms such as Augmented Reality (AR), Mixed Reality (MR), and Virtual Reality (VR), as well as various other types that span or sit between these examples. In the following, the term “XR” also refers to cloud gaming and related applications. In general, XR services require relatively high throughput (e.g., bit rates) and a latency that is relatively low and bounded, compared to certain other services.

[0008] 3GPP Rel-17 included a study item on XR for NR, with the main objectives being to identify the traffic model for each application of interest, the evaluation methodology and the key performance indicators of interest for relevant deployment scenarios, and to carry out performance evaluations to investigate possible standardization enhancements in follow-up Rel-18 work items.

[0009] This study determined that some XR applications may generate large PDUs that need to be segmented into multiple IP packets. To address this need, 3GPP Rel-18 specified a “PDU set” as “one or more PDUs carrying the payload of one unit of information generated at the application level (e.g., frame(s) or video slice(s) for XR services), as defined in 3GPP TS 23.501.” 3GPP Rel-18 also specified related QoS parameters including PDU Set Delay Budget (PSDB) and PDU Set Error Rate (PSER). While these were specified with XR services in mind, they are applicable to any service. Given this new information, a network can make more holistic PDU scheduling decisions and monitor delivery performance for application SDUs, as well as IP packets associated with individual application SDUs.

[0010] SUMMARY

[0011] Even so, the RAN in 5G networks only monitors / tracks IP packets, which have a “weak” relation to the application or service itself due to segmentation of large application SDUs into multiple IP packets (as discussed above) and combination of multiple small application SDUs into a single IP packet. As such, there may be many scenarios were network QoS performance at IP packet level does not match with application-level QoS or quality-of-experience (QoE) performance. Some solutions are needed.

[0012] An object of embodiments of the present disclosure is to improve observability of application performance in a RAN, such as by providing, enabling, and / or facilitating solutions to exemplary problems summarized above and described in more detail below.

[0013] Some embodiments include methods (e.g., procedures) for transmitting node configured to operate in a RAN.These exemplary methods include receiving a plurality of sets of PDUs generated by an application for transmission to a receiving node in the RAN. These exemplary methods also include transmitting the plurality of sets of PDUs to the receiving node. These exemplary methods also include sending, to the receiving node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application. The application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality:

[0014] • a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; and

[0015] • a second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

[0016] In some embodiments, the transmitting node determines Tl but not T2 for each PDU set of the plurality of PDU sets, and the application observability information includes a representation of Tl determined for each PDU set. These embodiments correspond to embodiments in which the receiving node determines T2 and other application observability information, as summarized below. In some of these embodiments, for each PDU set, the representation of Tl is included in a header of a protocol service data unit (SDU) that carries at least a portion of one or more PDUs of the PDU set.

[0017] In other embodiments, the transmitting node determines Tl and T2 for each PDU set of the plurality of PDU sets and these exemplary methods also include, for each PDU set, determining whether a difference, T2-T1, meets a PSDB requirement for the application. In some of these embodiments, these exemplary methods also include, when it is determined for a PDU set that T2-T1 does not meet the PSDB requirement, determining a portion of the PDU set whose transmission by the transmitting node met the PSDB requirement.

[0018] In some of these embodiments, these exemplary methods also include the following operations:

[0019] • estimating a PDU set error rate (PSER) based on a ratio of the following: how many PDU sets of the plurality for which T2-T1 was determined not to meet the PSDB requirement, to a total number of PDU sets of the plurality; and

[0020] • determining whether the estimated PSER meets a PSER requirement for the application.

[0021] In some of these embodiments, the application observability information sent to the receiving node includes one or more of the following:

[0022] • for each of the PDU sets, an indication of whether the difference, T2-T1, determined for the PDU set met the PSDB requirement for the application;

[0023] • one or more statistics for the differences, T2-T1, determined for the plurality of PDU sets;• one or more statistics related to how many PDUs of each PDU set met the PSDB;

[0024] • an estimated PDU set error rate (PSER) for the plurality of PDU sets; and

[0025] • an indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.

[0026] In other embodiments, the transmitting node may receive one or more of the above-listed application observability information from the receiving node, in accordance with receiving node embodiments summarized below.

[0027] Other embodiments include exemplary methods (e.g., procedures) for a receiving node configured to operate in a RAN. These embodiments are generally complementary to transmitting embodiments summarized above.

[0028] These exemplary methods include receiving, from a transmitting node in the RAN, a plurality of sets of PDUs generated by an application. These exemplary methods also include receiving, from the transmitting node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application. The received application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality:

[0029] • a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; and

[0030] • a second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

[0031] In some embodiments, the received application observability information includes a representation of Tl determined by the transmitting node. In some of these embodiments, for each PDU set, the representation of Tl is included in a header of a protocol service data unit (SDU) that carries at least a portion of one or more PDUs of the PDU set. In some of these embodiments, the exemplary method also includes the following operations:

[0032] • for each PDU set, determining the second time, T2, when a last-transmitted PDU of the PDU set was received by the receiving node; and

[0033] • for each PDU set, determining whether a difference, T2-T1, meets a PSDB requirement for the application.

[0034] In some variants of these embodiments, these exemplary methods also include, when it is determined that T2-T1 for a PDU set does not meet the PSDB requirement, determining a portion of the PDU set whose reception by the receiving node met the PSDB requirement. In some variants of these embodiments, these exemplary methods also includes the following operations:• estimating a PDU set error rate (PSER) based on a ratio of the following: how many PDU sets of the plurality for which T2-T1 was determined not to meet the PSDB requirement, to a total number of PDU sets of the plurality; and

[0035] • determining whether the estimated PSER meets a PSER requirement for the application.

[0036] In some variants of these embodiments, these exemplary methods also include sending one or more of the following application observability information to the transmitting node:

[0037] • for each of the PDU sets, an indication of whether the difference, T2-T1, determined for the PDU set met the PSDB requirement for the application;

[0038] • one or more statistics for the differences, T2-T1, determined for the plurality of PDU sets;

[0039] • one or more statistics related to how many PDUs of each PDU set met the PSDB;

[0040] • an estimated PSER for the plurality of PDU sets; and

[0041] • an indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.

[0042] In other embodiments, the receiving node may receive one or more of the above-listed application observability information from the transmitting node, in accordance with transmitting node embodiments summarized above.

[0043] In some embodiments, the transmitting node is a UE and the receiving node is a RAN node. In other embodiments, the transmitting node is a RAN node and the receiving node is a UE.

[0044] Other embodiments include transmitting nodes (e.g., UEs, RAN nodes) and receiving nodes (e.g., UEs, RAN nodes) configured to perform operations corresponding to any of the exemplary methods described herein. Other embodiments include non-transitory, computer-readable media storing program instructions that, when executed by processing circuitry, configure such transmitting or receiving nodes to perform operations corresponding to any of the exemplary methods described herein.

[0045] These and other embodiments described herein may provide various benefits and / or advantages. For example, embodiments may facilitate accurate monitoring and observation of application level QoE / QoS in a RAN. Given this accurate information about application level QoE / QoS, network operators may more easily establish and comply with service level agreements (SLAs) for a wider range of services and applications, especially those having service level latency requirements. As a more specific example, embodiments may facilitate delivery of XR services via RANs.

[0046] These and other objects, features, and advantages of embodiments of the present disclosure will become apparent upon reading the following Detailed Description in view of the Drawings briefly described below.BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figures 1-2 illustrate two high-level views of an exemplary 5G / NR network architecture. Figure 3 shows an exemplary configuration of NR user plane (UP) and control plane (CP) protocol stacks.

[0048] Figure 4 illustrates a comparison of various characteristics or requirements between XR and other 5G applications.

[0049] Figure 5 shows two exemplary PDU sets generated by an application over a period of time. Figure 6 illustrates how QoE deviates from QoS as packet error rate (PER) increases. Figure 7 shows a simplified block diagram of a system according to some embodiments of the present disclosure.

[0050] Figure 8 shows a flow diagram of an exemplary method for a transmitting node, according to various embodiments of the present disclosure.

[0051] Figure 9 shows a flow diagram of an exemplary method for a receiving node, according to various embodiments of the present disclosure.

[0052] Figure 10 shows a communication system according to various embodiments of the present disclosure.

[0053] Figure 11 shows a UE according to various embodiments of the present disclosure.

[0054] Figure 12 shows a network node according to various embodiments of the present disclosure.

[0055] Figure 13 is a block diagram of a virtualization environment in which functions implemented by some embodiments of the present disclosure may be virtualized.

[0056] DETAILED DESCRIPTION

[0057] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0058] In general, all terms used herein are to be interpreted according to their ordinary meaning to a person of ordinary skill in the relevant technical field, unless a different meaning is expressly defined and / or implied from the context of use. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise or clearly implied from the context of use. The operations of any methods and / or procedures disclosed herein do not have to be performed in the exact order disclosed, unless an operation is explicitly describedas following or preceding another operation and / or where it is implicit that an operation must follow or precede another operation. Any feature of any embodiment disclosed herein can apply to any other disclosed embodiment, as appropriate. Likewise, any advantage of any embodiment described herein can apply to any other disclosed embodiment, as appropriate.

[0059] Furthermore, the following terms are used throughout the description given below:

[0060] • Radio Access Node: As used herein, a “radio access node” (or equivalently “radio network node,” “radio access network node,” or “RAN node”) can be any node in a radio access network (RAN) that operates to wirelessly transmit and / or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g, gNB in a 3GPP 5G / NR network or an enhanced or eNB in a 3GPP LTE network), base station distributed components (e.g., CU and DU), a high-power or macro base station, a low-power base station (e.g., micro, pi co, femto, or home base station, or the like), an integrated access backhaul (IAB) node, a transmission point (TP), a transmission reception point (TRP), a remote radio unit (RRU or RRH), and a relay node.

[0061] • Core Network Node: As used herein, a “core network node” is any type of node in a core network. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a serving gateway (SGW), aPDN Gateway (P-GW), a Policy and Charging Rules Function (PCRF), an access and mobility management function (AMF), a session management function (SMF), a user plane function (UPF), a Charging Function (CHF), a Policy Control Function (PCF), an Authentication Server Function (AUSF), a location management function (LMF), or the like.

[0062] • Wireless Device: As used herein, a “wireless device” (or “WD” for short) is any type of device that is capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other wireless devices. Communicating wirelessly can involve transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information through air. Unless otherwise noted, the term “wireless device” is used interchangeably herein with the term “user equipment” (or “UE” for short), with both of these terms having a different meaning than the term “network node”.

[0063] • Radio Node: As used herein, a “radio node” can be either a “radio access node” (or equivalent term) or a “wireless device.”

[0064] • Network Node: As used herein, a “network node” is any node that is either part of the radio access network (e.g, a radio access node or equivalent term) or of the core network (e.g., a core network node discussed above) of a cellular communications network. Functionally, a network node is equipment capable, configured, arranged, and / or operable tocommunicate directly or indirectly with a wireless device and / or with other network nodes or equipment in the cellular communications network, to enable and / or provide wireless access to the wireless device, and / or to perform other functions (e.g., administration) in the cellular communications network.

[0065] • Node: As used herein, the term “node” (without prefix) can be any type of node that can in or with a wireless network (including RAN and / or core network), including a radio access node (or equivalent term), core network node, or wireless device. However, the term “node” may be limited to a particular type (e.g., radio access node, IAB node) based on its specific characteristics in any given context.

[0066] The above definitions are not meant to be exclusive. In other words, various ones of the above terms may be explained and / or described elsewhere in the present disclosure using the same or similar terminology. Nevertheless, to the extent that such other explanations and / or descriptions conflict with the above definitions, the above definitions should control.

[0067] Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system and can be applied to any communication system that may benefit from them.

[0068] Figure 1 illustrates a high-level view of an exemplary 5G network architecture, consisting of a Next Generation Radio Access Network (NG-RAN, 199) and a 5G Core (5GC, 198). The NG-RAN can include one or more gNodeB’s (gNBs) connected to the 5GC via one or more NG interfaces, such as gNBs (100, 150) connected via respective interfaces (102, 152). More specifically, the gNBs can be connected to one or more Access and Mobility Management Functions (AMFs) in the 5GC via respective NG-C interfaces and to one or more User Plane Functions (UPFs) in 5GC via respective NG-U interfaces. The 5GC can include various other network functions (NFs), such as Session Management Function(s) (SMF).

[0069] In addition, the gNBs can be connected to each other via one or more Xn interfaces, such as Xn interface (140) between gNBs (100, 150). The radio technology for the NG-RAN is often referred to as “New Radio” (NR). With respect to the NR interface to user equipment (UEs), each of the gNBs can support frequency division duplexing (FDD), time division duplexing (TDD), or a combination thereof. Each of the gNBs can serve a geographic coverage area including one or more cells.

[0070] In addition, NR networks also provide coverage via “beams.” In general, a downlink (DL, i.e., network to UE) “beam” is a coverage area of a network-transmitted reference signal (RS) that may be measured or monitored by a UE. In NR, for example, DL RS can include any of the following: synchronization signal / PBCH block (SSB), channel state information RS (CSI-RS),tertiary reference signals (or any other sync signal), positioning RS (PRS), demodulation RS (DMRS), phase-tracking reference signals (PTRS), and positioning reference signals (PRS). In general, SSB is available to all UEs regardless of the state of their connection with the RAN, while other RS are associated with specific UEs that have a network connection.

[0071] NG RAN logical nodes (e.g., gNB 100) may include a Central Unit (CU or gNB-CU, e.g., 110) and one or more Distributed Units (DU or gNB-DU, e.g., 120, 130). CUs are logical nodes that host higher-layer protocols and perform various gNB functions such controlling the operation of DUs. DUs are decentralized logical nodes that host lower layer protocols and can include, depending on the functional split option, various subsets of the gNB functions. Each CU and DU can include various circuitry needed to perform their respective functions, including processing circuitry, communication interface circuitry (e.g., transceivers), and power supply circuitry.

[0072] A gNB-CU connects to one or more gNB-DUs over respective Fl logical interfaces (e.g., 122 and 132 shown in Figure 1). However, a gNB-DU can be connected to only a single gNB-CU. The gNB-CU and its connected gNB-DU(s) are only visible to other gNBs and the 5GC as a gNB. In other words, the Fl interface is not visible beyond gNB-CU.

[0073] Figure 2 shows another high-level view of an exemplary 5G network architecture, including an NG-RAN (299) and a 5GC (298). As shown in the figure, the NG-RAN can include gNBs (e.g, 210a,b) and ng-eNBs (e.g, 220a, b) that are interconnected with each other via respective Xn interfaces. An ng-eNB is similar to a fourth generation (4G) Long-Term Evolution (LTE) eNB, except that it supports the Xn and NG interfaces rather than corresponding X2 and SI interfaces.

[0074] The gNBs and ng-eNBs are also connected via the NG interfaces to the 5GC, more specifically to AMFs e.g. , 230a, b) via respective NG-C interfaces and to UPFs (e.g. , 240a,b) via respective NG-U interfaces. Moreover, the AMFs can communicate with one or more policy control functions (PCFs, e.g., 250a, b) and network exposure functions (NEFs, e.g., 260a, b).

[0075] Each of the gNBs can support the NR radio interface including frequency division duplexing (FDD), time division duplexing (TDD), or a combination thereof. Each of ng-eNBs can support the 4G / LTE radio interface. Each of the gNBs and ng-eNBs can serve a geographic coverage area including one or more cells (e.g., 211a-b and 221a-b). Depending on the cell in which it is located, UEs (e.g., 205) can communicate with the gNB or ng-eNB serving that cell via the NR or LTE radio interface, respectively. Although Figure 2 shows gNBs and ng-eNBs separately, it is also possible that a single NG-RAN node provides both LTE and NR functionality.

[0076] 5G / NR technology shares many similarities with fourth-generation LTE. For example, NR uses CP-OFDM (Cyclic Prefix Orthogonal Frequency Division Multiplexing) in the DL and both CP-OFDM and DFT-spread OFDM (DFT-S-OFDM) in the UL. As another example, in the timedomain, NR DL and UL physical resources are organized into equal-sized 1-ms subframes. A subframe is further divided into multiple slots of equal duration, with each slot including multiple OFDM-based symbols. An NR slot can include 14 OFDM symbols for normal cyclic prefix and 12 symbols for extended cyclic prefix. A resource block (RB) consists of a group of 12 contiguous OFDM subcarriers for a duration of a 12- or 14-symbol slot. A resource element (RE) corresponds to one OFDM subcarrier during one OFDM symbol interval.

[0077] Figure 3 shows exemplary NR user plane (UP) and control plane (CP) protocol stacks between a UE (310), a gNB (320), and an AMF (330), such as those shown in Figures 1-2. The Physical (PHY), Medium Access Control (MAC), Radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP) layers between the UE and the gNB are common to UP and CP. The PDCP layer provides ciphering / deciphering, integrity protection, sequence numbering, reordering, and duplicate detection for both CP and UP. In addition, PDCP provides header compression and retransmission for UP data.

[0078] On the UP side, Internet protocol (IP) packets arrive to PDCP as service data units (SDUs), and PDCP creates protocol data units (PDUs) to deliver to RLC. The Service Data Adaptation Protocol (SDAP) layer handles quality-of-service (QoS) including mapping between QoS flows and Data Radio Bearers (DRBs) and marking QoS flow identifiers (QFI) in UL and DL packets.

[0079] When each IP packet arrives, PDCP starts a discard timer. When this timer expires, PDCP discards the associated SDU and the corresponding PDU. If the PDU was delivered to RLC, PDCP also indicates the discard to RLC. The RLC layer transfers PDCP PDUs to the MAC through logical channels (LCH). RLC provides error detection / correction, concatenation, segmentation / reassembly, sequence numbering, reordering of data transferred to / from the upper layers. If RLC receives a discard indication from associated with a PDCP PDU, it will discard the corresponding RLC SDU (or any segment thereof) if it has not been sent to lower layers.

[0080] MAC provides mapping between LCHs and PHY transport channels, LCH prioritization, multiplexing into or demultiplexing from transport blocks (TBs), hybrid ARQ (HARQ) error correction, and dynamic scheduling (in gNB). PHY provides transport channel services to MAC and handles transfer over the NR radio interface, e.g., via modulation, coding, antenna mapping, and beam forming.

[0081] On the CP side, the non-access stratum (NAS) layer between UE and AMF handles UE / gNB authentication, mobility management, and security control. RRC sits below NAS in the UE but terminates in the gNB rather than the AMF. RRC controls communications between UE and gNB at the radio interface as well as the mobility of a UE between cells in the NG-RAN. RRC also broadcasts system information (SI) and performs establishment, configuration, maintenance, and release of DRBs and Signaling Radio Bearers (SRBs) and used by UEs. Additionally, RRCcontrols addition, modification, and release of carrier aggregation (CA) and dual-connectivity (DC) configurations for UEs, and performs various security functions such as key management.

[0082] After a LIE is powered ON it will be in the RRCJ1DLE state until an RRC connection is established with the network, at which time the UE will transition to RRC CONNECTED state (e.g, where data transfer can occur). The UE returns to RRC TDLE after the connection with the network is released. In RRCJODLE state, the UE’s radio is active on a discontinuous reception (DRX) schedule configured by upper layers. During DRX active periods (also referred to as “DRX On durations”), an RRC IDLE UE receives SI broadcast in the cell where the UE is camping, performs measurements of neighbor cells to support cell reselection, and monitors a paging channel on PDCCH for pages from 5GC via gNB. An NR UE in RRC IDLE state is not known to the gNB serving the cell where the UE is camping. However, NR RRC includes an RRC_INACTIVE state in which a UE is known (e.g., via UE context) by the serving gNB. RRC INACTIVE has some properties similar to a “suspended” condition used in LTE.

[0083] 5G / NR is designed to support applications demanding high rate and low latency in line with the requirements for supporting XR and cloud gaming applications. 3GPP Rel-17 includes a study item (SI) on XR Evaluations for NR. The main objectives were to identify traffic model for each application of interest, identify evaluation methodology and key performance indicators for relevant deployment scenarios, and carry out performance evaluations to investigate possible standardization enhancements in follow-up Rel-18 work items.

[0084] Figure 4 illustrates a high-level comparison of various characteristics requirements for XR and other 5G applications. In particular, Figure 4 shows a comparison of latency, reliability, and data rate requirements for URLLC, streaming, and XR. While URLLC services have extreme requirements of 1-ms latency and of ICT5, XR services can have relaxed requirements of 5-10 ms latency and IO reliability. However, XR services can require a much higher bit rate than either URLLC or streaming, (e.g., due to codec inefficiency). XR traffic can also be very dynamic, e.g., due to eye / viewport tracking.

[0085] XR requires bounded latency but not necessarily ultra-low latency. However, the end-to-end latency (or packet delay) budget (e.g., 20-80 ms) must 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 may not be effective.

[0086] In general, XR traffic is relatively periodic in arrival time but average data rate requirement and dominant transmission direction (e.g., UL or DL) is dependent on the particular XR-related service. Table 1 below gives an exemplary characterization of XR services by data rate (or throughput) requirements and dominant transmission direction.Table 1.

[0087]

[0088] The Rel-17 study determined that XR applications may generate large PDUs that need to be segmented into multiple IP packets and transmitted as several transport blocks (TBs) during multiple transmit time intervals (TTIs) in the RAN. For example, video frame sizes may range from tens to hundreds of kilobytes (kB). As a more specific example, a median number of five (5) TBs are needed to deliver a 200-kB video frame but for ~5% of 200-kB video frames, 15 or more TBs are needed.

[0089] To address this need, 3GPP Rel-18 specified a “PDU set” as “one or more PDUs carrying the payload of one unit of information generated at the application level (e.g., frame(s) or video slice(s) for XR Services), as defined in 3GPP TS 23.501.” Figure 5 shows two exemplary PDU sets generated by an application over a period of time, with each PDU set including five (5) PDUs. For example, the two PDU sets in Figure 5 may contain respective video frames generated by an XR service or application.

[0090] 3GPP Rel-18 also specified related QoS parameters including PDU set Delay Budget (PSDB) and PDU set Error Rate (PSER). While these were specified with XR services in mind, they are applicable to any service. Given this new information, a 5G network can make more holistic PDU scheduling decisions and monitor delivery performance for application SDUs, as well as IP packets associated with individual application SDUs.

[0091] Even so, the NG-RAN only monitors / tracks IP packets, which have a “weak” relation to the application or service itself due to segmentation of large application SDUs into multiple IP packets (as discussed above) and combination of multiple small application SDUs into a single IP packet. As such, there may be many scenarios were network QoS performance at IP packet level does not match with application-level QoS or quality-of-experience (QoE) performance.

[0092] Consider the following example. An application generates PDUs with a certain periodicity. Each application PDU is further segmented into 100 IP packets. A QoS of 1 % PER at the IP packet level is required, meaning that one of every 100 IP packets may be dropped, not delivered, or delivered too late. In contrast, the application-level quality of experience (QoE) requirement is 1% PSER, meaning that one of every 100 application PDUs may be dropped, not delivered, or delivered too late.

[0093] Figure 6 illustrates how QoE deviates from QoS as the PER increases toward the 1% requirement. When PER is very low, PSER is also very low since it is still rare to have an error inevery 100 IP packets. As PER increases, PSER increases even more quickly since it is more likely that at least one of every 100 IP packets constituting an application PDU will be lost. In fact, as PER approaches 1%, PSER approaches 100% since at least one of every 100 IP packets constituting an application PDU is likely to be lost. As this example shows, meeting IP packetlevel QoS requirements does not guarantee meeting application-level QoE requirements.

[0094] Accordingly, embodiments of the present disclosure provide flexible and efficient techniques for monitoring and observation of application level QoE / QoS in a RAN. In some embodiments, a transmitting node performs all required measurements and observation procedures. In other embodiments, the transmitting node adds information in protocol headers that is used by the receiving node to complete required measurement and - when the receiving node is a UE - report the measurement results to the RAN.

[0095] Embodiments can provide various benefits and / or advantages. For example, embodiments may facilitate accurate monitoring and observation of application level QoE / QoS in a RAN. Given this accurate information about application level QoE / QoS, network operators may more easily establish and comply with service level agreements (SLAs) for a wider range of services and applications, especially those having service level latency requirements. As a more specific example, embodiments may facilitate delivery of XR services via RANs.

[0096] In various embodiments described below, It is assumed that UPF in the 5GC sends PDU set information to the RAN. This PDU set information may include QoS flow identifier, PDU set sequence number (SN), PDU SN within a PDU set, indicator of end PDU of a PDU set, PDU set importance indicator, and / or PDU set size (e.g., in bytes or kilobytes).

[0097] Figure 7 shows a simplified block diagram of a communication system according to some embodiments of the present disclosure. The communication system shown in Figure 7 includes a transmitting node (710) and a receiving node (720). An application (e.g., client) in the transmitting node generates application PDU sets and transmit them to a corresponding application (e.g., server) in the receiving node, via compatible protocol stacks in the respective nodes. For example, one or more of the protocol stacks shown in Figure 3 may be used for this purposes.

[0098] In some variants, one or both of the applications may be external to the nodes in which they are shown in Figure 7. For example, if the transmitting node is a UE and the receiving node is a RAN node, the application may be internal to the transmitting node but external to the receiving node, such as in an AF coupled to the RAN node via a core network. As another example, if the transmitting node is a RAN node and the receiving node is a UE, the application may be internal to the receiving node but external to the transmitting node, such as in an AF coupled to the RAN node via a core network. The applications are shown within the respective nodes in Figure 7 only for simplicity and convenience.Each of the transmitting and receiving nodes includes an Analysis block interposed between the application and the protocol stack. Each Analysis block performs operations in accordance with various embodiments described below, including sending / receiving various information to / from the other Analysis block via the compatible protocol stacks in the two nodes. This exchanged information may be referred to as “application observability information” with specific embodiments described in more detail below.

[0099] In some embodiments, when the transmitting node receives a first PDU of a PDU set, the transmitting node records the reception or entry time (e.g., Tl) of this PDU. Note that “first PDU” does not necessarily mean the initial PDU in sequence for the PDU set, but rather the initially received PDU for the PDU set. The transmitting node may determine the last PDU of the PDU set using various PDU set information such as the indicator of end PDU, the PDU set size, PDU SN within PDU set, etc. When the last PDU of the PDU set is transmitted, the transmitting node records the transmission time (e.g., T2). If retransmissions are allowed, the transmitting node records the transmission time of the last retransmitted PDU of the PDU set (e.g., as T2).

[0100] In some variants, instead of recording the transmission time of the last PDU of the PDU set as T2, the transmitting node estimates T2 as the time of successful reception of the last PDU of the PDU set at the receiving node. The successful reception of the last PDU can be estimated by the transmitting node in various ways. For example, in DL, the transmitting node (gNB) will wait for HARQ ACK / NACK feedback from the UE and records T2 as the time it received a HARQ ACK for the last PDU of the PDU set. In UL, the transmitting node (UE) may record T2 as the time when a retransmission timer for the last PDU (e.g., cg-retransmissionTimer for a configured UL grant) expires or a duration after the last PDU is transmitted that is long enough to ensure any retransmission is sent.

[0101] In some of these embodiments, the transmitting node calculates (T2-T1) and compares it against the PSDB for the application. If PSDB is greater than or equal to (T2-T1), the transmitting node determines that the PDU set meets the application-level QoE. Otherwise, the transmitting node determines that the PDU set does not meet the application-level QoE, and counts the PDU set as part of the PSER (i.e., not correctly received).

[0102] In some variants, the transmitting node may count how many PDU sets do not meet PSDB for the application out of the total PDU sets sent by / for the application. In other words, the transmitting node can estimate PSER for the application based on actual PDU set traffic and PSDB. In this manner, the transmitting node can determine whether estimated PSER meets a QoE requirement for the application.

[0103] In some variants, if the transmitting node is the UE, the UE may report its results to the RAN (e.g., serving RAN node as receiving node) periodically, upon request, upon occurrence ofa reporting trigger event, or a combination thereof. In each report, the UE may include one or more of the following measurement results obtained over some measurement duration:

[0104] • Measured / estimated PSER;

[0105] • Minimum, maximum, and / or mean values for measured (T2-T1); and

[0106] • Portion of a PDU set that was successfully received (e.g., min, max, and / or mean values). In some variants, the measurement results may be provided per PDU set type, per PDU set importance level, or other granularity.

[0107] If the transmitting node is the UE, the RAN may configure these service observability operations performed by the UE. For example, the RAN may provide the relevant configuration parameters for the UE measurements and reporting, such as PSDB requirement, PSER target, measurements to report, measurement duration (e.g., for averaging and / or rate determinations), report trigger conditions, etc.

[0108] In other embodiments, when the transmitting node receives a first PDU of a PDU set, the transmitting node records the reception or entry time (e.g., Tl) of this PDU and adds T1 to one of the RAN protocol headers. Note that “first PDU” does not necessarily mean the initial PDU in sequence for the PDU set. Also, note that the information added to the header may be any time-related information that enables the transmitting and receiving nodes to identify actual time Tl with reasonable accuracy. For example, the time-related information may be a radio interface timing event such as a combination of hyperframe number (HFN), subframe number (SFN), slot number, and symbol number. When the receiving node receives the PDU that includes Tl in the protocol header, it stores the received Tl information.

[0109] For example, depending on the latency range expected to be measured, a few lower-order bits of the conventional 10-bit SFN could be added to the header. This may be suitable for immersive communication applications in XR, where expected latencies are below 50 ms. In such case, the three lowest-order bits of the SFN may provide sufficient range.

[0110] In some variants, the slot number may be added with a varying size depending on the subcarrier spacing (SCS) being used for communication between UE and RAN. For example, with 15-kHz SCS there are 10 slots per frame so four (4) bits may be used to indicate slot number. For 30-kHz SCS there are 20 slots per frame so five (5) bits may be used to indicate slot number. For 60-kHz SCS there are 40 slots per frame so six (6) bits may be used to indicate slot number. For 120-kHz SCS there are 80 slots per frame so seven (7) bits may be used to indicate slot number.

[0111] In some variants, the symbol number within a slot may be added to give further resolution. With 14 symbols per slot, four (4) bits may be added to indicate symbol number.

[0112] In some of these embodiments, the transmitting node may add to the header additional PDU set information to help the receiving node identify PDU sets for performing the requiredmeasurements. For example, the transmitting node may add a PDU set SN, a PDU SN within PDU set, etc. As a more specific example, the transmitting node may add a few lower-order bits of the conventional 10-bit PDU set SN in order to reduce overhead of the reported information. This may be sufficient for identifying individual PDU sets so long as a UE only buffers a few PDU sets at a given time (as expected).

[0113] In some of these embodiments, the receiving node may determine the times at which it receives PDUs of the PDU set and store these times for the respective PDUs.

[0114] In some of these embodiments, the transmitting node may determine the last PDU of the PDU set using various PDU set information such as the indicator of end PDU, PDU set size, PDU SN within PDU set, etc. When the last PDU of the PDU set is transmitted, the transmitting node adds to the corresponding RAN protocol header an indication that this is the last PDU of the PDU set.

[0115] In some of these embodiments, when the receiving node receives the PDU including the protocol header with the indication that this is the last PDU of the PDU set, the receiving node records the time at which this PDU was successfully received (e.g., as T2). The receiving node may determine whether there are other PDUs of the PDU set that are in retransmission and have not yet been successfully received, such as based on a PDU SN in PDU set information the transmitting node included in the protocol header. If there are pending PDUs, the receiving node records the time at which the last pending PDU of the PDU set was successfully received (e.g., as T2).

[0116] In some of these embodiments, the receiving node calculates (T2-T1) and compares it against the PSDB for the application. If PSDB is greater than or equal to (T2-T1), the receiving node determines that the PDU set meets the application-level QoE. Otherwise, the receiving node determines that the PDU set does not meet the application-level QoE, and counts the PDU set as part of the PSER (i.e., not correctly received).

[0117] In some variants, the receiving node may count how many PDU sets do not meet PSDB for the application out of the total PDU sets sent for the application. In other words, the receiving node can estimate PSER for the application based on actual PDU set traffic and PSDB. In this manner, the receiving node can determine whether estimated PSER meets a QoE requirement for the application.

[0118] In some variants, after the receiving node determines whether (T2-T1) is less than the PSDB, the receiving node can also indicate to the transmitting node whether the PDU set met the application-level QoE. Based on this indication, the transmitting node will count the PDU set towards meeting or not meeting the application-level QoE, i.e., as part of the PSER estimation.In some variants, if the receiving node is unable to calculate (T2-T1) for a PDU set due to, for instance, not receiving all PDUs of the PDU set within a predefined time (e.g., the PSDB), the receiving node may stop monitoring the PDU set and counts the PDU set as part of the PSER (i.e., not correctly received). One way for a receiving node to know some PDUs are missing is compare PDU set size information with size of PDUs of the PDU set that were received within the predetermined time.

[0119] In some further variants, if the receiving node is a UE, the UE may also determine and report the portion of the PDU set that was successfully received within the predetermined time. For example, this metric may indicate the ratio or percentage of successfully received PDUs (e.g., within PDSB) to the total number of PDUs that constitute the PDU set.

[0120] In some variants, if the receiving node is a UE, the UE may report its results to the RAN (e.g., serving RAN node) periodically, upon request, upon occurrence of a reporting trigger event, or a combination thereof. In each report, the UE may include one or more of the following measurement results obtained over some measurement duration:

[0121] • Measured / estimated PSER;

[0122] • Minimum, maximum, and / or mean values for measured (T2-T1); and

[0123] • Portion of PDU set that was successfully received (e.g., min, max, and / or mean values). In some variants, the measurement results may be provided per PDU set type, per PDU set importance level PDU set, or other granularity.

[0124] If the receiving node is the UE, the RAN may configure these service observability operations performed by the UE. For example, the RAN may provide the relevant configuration parameters for the UE measurements and reporting, such as PSDB requirement, PSER target, measurements to report, measurement duration (e.g., for averaging and / or rate determinations), report trigger conditions, etc.

[0125] Various features of the embodiments described above correspond to various operations illustrated in Figures 8-9, which show exemplary methods (e.g, procedures) for a transmitting node and a receiving node, respectively. In other words, various features of the operations described below correspond to various embodiments described above. Furthermore, the exemplary methods shown in Figures 8-9 can be used cooperatively to provide various benefits, advantages, and / or solutions to problems described herein. Although Figures 8-9 show specific blocks in particular orders, the operations of the exemplary methods can be performed in different orders than shown and can be combined and / or divided into blocks having different functionality than shown. Optional blocks or operations are indicated by dashed lines.

[0126] In particular, Figure 8 shows an exemplary method (e.g., procedure) for a transmitting node configured to operate in a RAN, according to various embodiments of the present disclosure.The exemplary method can be performed by any appropriate node (e.g., UE, wireless device, base station, eNB, gNB, ng-eNB, etc.) such as described elsewhere herein.

[0127] The exemplary method includes the operations of block 820, where the transmitting node receives a plurality of sets of PDUs generated by an application for transmission to a receiving node in the RAN. The exemplary method also includes the operations of block 830, where the transmitting node transmits the plurality of sets of PDUs to the receiving node. The exemplary method also includes the operations of block 840, where the transmitting node sends, to the receiving node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application. The application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality:

[0128] • a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; and

[0129] • a second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

[0130] In some embodiments, the transmitting node is a UE and the receiving node is a RAN node. In other embodiments, the transmitting node is a RAN node and the receiving node is a UE.

[0131] In some embodiments, the exemplary method also includes the operations of block 815, where the transmitting node receives from the receiving node a configuration for reporting application observability information. The application observability information is sent to the receiving node (e.g., in block 840) in accordance with the configuration. In some of these embodiments, the configuration includes or indicates one or more of the following:

[0132] • a PDU set delay budget (PSDB) requirement for the application,

[0133] • a PDU set error rate (PSER) requirement for the application,

[0134] • which application observability information to report,

[0135] • a quantity of PDU sets for which application observability information should be reported, • a duration between periodic application observability information reports, and

[0136] • one or more aperiodic reporting conditions.

[0137] In some embodiments, the transmitting node determines Tl but not T2 for each PDU set of the plurality of PDU sets, and the application observability information includes a representation of Tl determined for each PDU set. These embodiments correspond to embodiments in which the receiving node determines T2 and other application observability information, as described in more detail below.

[0138] In some of these embodiments, for each PDU set, the representation of Tl is included in a header of a protocol service data unit (SDU) that carries at least a portion of one or more PDUs ofthe PDU set. In some variants of these embodiments, each PDU set of the plurality of PDU sets is received together with one or more of the following associated information: quality -of-service (QoS) flow identifier, PDU set sequence number, sequence numbers of each PDU of the PDU set, indicator of end PDU of the PDU set, PDU set importance indicator, and PDU set size. Additionally, at least one of the associated information is included in the header of the SDU together with the representation of Tl.

[0139] In some of these embodiments, the representation of Tl includes or indicates one or more of the following parameters that identify a timing event on a radio interface between the transmitting node and the receiving node: hyperframe number, subframe number, slot number, and symbol number. In some variants of these embodiments, the subframe number is represented by a first plurality of bits, the slot number is represented by a second plurality of bits, the symbol number is represented by a third plurality of bits, and the representation of Tl includes lowest-order subsets of at least one of the first, second, and third pluralities of bits.

[0140] In some of these embodiments, the exemplary method also includes the operations of block 850, where receiving one or more of the following application observability information from the receiving node:

[0141] • for each of the PDU sets, an indication of whether a difference, T2-T1, for the PDU set met a PDU set delay budget (PSDB) requirement for the application;

[0142] • one or more statistics for the differences, T2-T1, for the plurality of PDU sets;

[0143] • one or more statistics related to how many PDUs of each PDU set met the PSDB;

[0144] • an estimated PDU set error rate (PSER) for the plurality of PDU sets; and

[0145] • an indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.

[0146] In some variants of these embodiments, the exemplary method also includes the operations of block 810, where the transmitting node sends to the receiving node a further configuration for reporting application observability information. The application observability information is received from the receiving node (e.g., in block 850) in accordance with the further configuration.

[0147] In other embodiments, the transmitting node determines Tl and T2 for each PDU set of the plurality of PDU sets and the exemplary method also includes the operations of block 860, where for each PDU set, the transmitting node determines whether a difference, T2-T1, meets a PSDB requirement for the application. In some of these embodiments, the exemplary method also includes the operations of block 870, where when it is determined for a PDU set that T2-T1 does not meet the PSDB requirement, the transmitting node determines a portion of the PDU set whose transmission by the transmitting node met the PSDB requirement.In some of these embodiments, the exemplary method also includes the following operations, labelled with corresponding block numbers:

[0148] • (880) estimating a PDU set error rate (PSER) based on a ratio of the following: how many PDU sets of the plurality for which T2-T1 was determined not to meet the PSDB requirement, to a total number of PDU sets of the plurality; and

[0149] • (890) determining whether the estimated PSER meets a PSER requirement for the application.

[0150] In some of these embodiments, the application observability information includes one or more of the following:

[0151] • for each of the PDU sets, an indication of whether the difference, T2-T1, determined for the PDU set met the PSDB requirement for the application;

[0152] • one or more statistics for the differences, T2-T1, determined for the plurality of PDU sets;

[0153] • one or more statistics related to how many PDUs of each PDU set met the PSDB;

[0154] • an estimated PDU set error rate (PSER) for the plurality of PDU sets; and

[0155] • an indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.

[0156] In some of these embodiments, the application observability information is sent (e.g., in block 840) in response to one of the following: receiving a request from the receiving node for application observability information (e.g., in block 835), expiration of a periodic reporting timer, or one or more aperiodic reporting conditions being met.

[0157] In some of these embodiments, each PDU set of the plurality is received together with one or more of the following associated information: quality-of-service (QoS) flow identifier, PDU set sequence number, sequence numbers of each PDU of the PDU set, indicator of end PDU of the PDU set, PDU set importance indicator, and PDU set size. In such embodiments, T2 for each PDU set is determined as when the last-transmitted PDU of the PDU set was transmitted by the transmitting node, based on the associated information for the PDU set. In some of these embodiments, T2 for each PDU set is determined further based on timing of a final retransmission of the last-transmitted PDU of the PDU set.

[0158] In some of these embodiments, T2 for each PDU set is determined as when the last-transmitted PDU of the PDU set was received by the receiving node, based one of the following:

[0159] • when the transmitting node received a hybrid ARQ acknowledgement (ACK) associated with the last-transmitted PDU of the PDU set;

[0160] • when a retransmission timer associated with the last-transmitted PDU of the PDU set expires; or• a duration that is long enough to ensure any retransmission of the last-transmitted PDU of the PDU set has been sent.

[0161] In addition, Figure 9 shows an exemplary method (e.g., procedure) for a receiving node configured to operate in a RAN, according to various embodiments of the present disclosure. The exemplary method can be performed by any appropriate node (e.g., UE, wireless device, base station, eNB, gNB, ng-eNB, etc.) such as described elsewhere herein.

[0162] The exemplary method includes the operations of block 920, where the receiving node receives, from a transmitting node in the RAN, a plurality of sets of PDUs generated by an application. The exemplary method also includes the operations of block 930, where the receiving node receives, from the transmitting node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application. The received application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality:

[0163] • a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; and

[0164] • a second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

[0165] In some embodiments, the transmitting node is a UE and the receiving node is a RAN node. In other embodiments, the transmitting node is a RAN node and the receiving node is a UE.

[0166] In some embodiments, the exemplary method also includes the operations of block 915, where the receiving node sends to the transmitting node a configuration for reporting application observability information. The application observability information is received from the transmitting node in accordance with the configuration. In some of these embodiments, the configuration includes or indicates one or more of the following:

[0167] • a PDU set delay budget (PSDB) requirement for the application,

[0168] • a PDU set error rate (PSER) requirement for the application,

[0169] • which application observability information to report,

[0170] • a quantity of PDU sets for which application observability information should be reported, • a duration between periodic application observability information reports, and

[0171] • one or more aperiodic reporting conditions.

[0172] In some embodiments, the received application observability information includes a representation of Tl determined by the transmitting node. In some of these embodiments, the exemplary method also includes the following operations, labelled with corresponding block numbers:• (940) for each PDU set, determining the second time, T2, when a last-transmitted PDU of the PDU set was received by the receiving node; and

[0173] • (950) for each PDU set, determining whether a difference, T2-T1, meets a PDU set delay budget (PSDB) requirement for the application.

[0174] In some variants of these embodiments, the exemplary method also includes the operations of block 960, where when it is determined that T2-T1 for a PDU set does not meet the PSDB requirement, the receiving node determines a portion of the PDU set whose reception by the receiving node met the PSDB requirement.

[0175] In some variants of these embodiments, the exemplary method also includes the following operations, labelled with corresponding block numbers:

[0176] • (970) estimating a PDU set error rate (PSER) based on a ratio of the following: how many PDU sets of the plurality for which T2-T1 was determined not to meet the PSDB requirement, to a total number of PDU sets of the plurality; and

[0177] • (980) determining whether the estimated PSER meets a PSER requirement for the application.

[0178] In some variants of these embodiments, for each PDU set, the representation of T1 is included in a header of a protocol service data unit (SDU) that carries at least a portion of one or more PDUs of the PDU set. In some further variants, at least one of the following associated information is included in the header of the SDU together with the representation of Tl: quality -of-service (QoS) flow identifier, PDU set sequence number, sequence numbers of each PDU of the PDU set, indicator of end PDU of the PDU set, PDU set importance indicator, and PDU set size. In such further variants; T2 is determined further based on the associated information for the PDU set.

[0179] In some variants of these embodiments, T2 for each PDU set is determined further based on when a final retransmission of the last-transmitted PDU of the PDU set is received by the receiving node. In some variants of these embodiments, the exemplary method also includes the operations of block 990, where the receiving node sends one or more of the following application observability information to the transmitting node:

[0180] • for each of the PDU sets, an indication of whether the difference, T2-T1, determined for the PDU set met the PSDB requirement for the application;

[0181] • one or more statistics for the differences, T2-T1, determined for the plurality of PDU sets;

[0182] • one or more statistics related to how many PDUs of each PDU set met the PSDB;

[0183] • an estimated PDU set error rate (PSER) for the plurality of PDU sets; and

[0184] • an indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.In some further variants, the exemplary method also includes the operations of block 910, where the receiving node receives from the transmitting node a further configuration for reporting application observability information. The application observability information is sent to the transmitting node in accordance with the further configuration.

[0185] In some of these embodiments, the representation of T1 includes or indicates one or more of the following parameters that identify a timing event on a radio interface between the transmitting node and the receiving node: hyperframe number, subframe number, slot number, and symbol number. In some variants of these embodiments, the subframe number is represented by a first plurality of bits, the slot number is represented by a second plurality of bits, the symbol number is represented by a third plurality of bits, and the representation of T1 includes lowest-order subsets of at least one of the first, second, and third pluralities of bits.

[0186] In other embodiments, the received application observability information includes one or more of the following:

[0187] • for each of the PDU sets, an indication of whether a difference, T2-T1, determined for the PDU set met a PSDB requirement for the application;

[0188] • one or more statistics for the differences, T2-T1, determined for the plurality of PDU sets;

[0189] • one or more statistics related to how many PDUs of each PDU set met the PSDB;

[0190] • an estimated PSER for the plurality of PDU sets; and

[0191] • an indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.

[0192] In some of these embodiments, the application observability information is received in response to one of the following: sending a request to the transmitting node for application observability information (e.g., in block 925), expiration of a periodic reporting timer at the transmitting node, or one or more aperiodic reporting conditions being met at the transmitting node.

[0193] Although various embodiments are described above in terms of methods, techniques, and / or procedures, the person of ordinary skill will readily comprehend that such methods, techniques, and / or procedures can be embodied by various combinations of hardware and software in various systems, communication devices, computing devices, control devices, apparatuses, non-transitory computer-readable media, computer program products, etc.

[0194] Figure 10 shows an example of a communication system 1000 in accordance with some embodiments. In this example, communication system 1000 includes a telecommunication network 1002 that includes an access network 1004, such as a radio access network (RAN), and a core network 1006, which includes one or more core network nodes 1008. The access network 1004 includes one or more access network nodes, such as network nodes lOlOa-b (one or more of which may be generally referred to as network nodes 1010), or any other similar 3GPP accessnode or non-3GPP access point. Network nodes 1010 facilitate direct or indirect connection of UEs, such as by connecting UEs 1012a-d (one or more of which may be generally referred to as UEs 1012) to core network 1006 over one or more wireless connections.

[0195] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, communication system 1000 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. Communication system 1000 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0196] UEs 1012 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with network nodes 1010 and other communication devices. Similarly, network nodes 1010 are arranged, capable, configured, and / or operable to communicate directly or indirectly with UEs 1012 and / or with other network nodes or equipment in telecommunication network 1002 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in telecommunication network 1002.

[0197] In the depicted example, core network 1006 connects network nodes 1010 to one or more hosts, such as host 1016. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. Core network 1006 includes one or more core network nodes (e.g., 1008) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 1008. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0198] Host 1016 may be under the ownership or control of a service provider other than an operator or provider of access network 1004 and / or telecommunication network 1002, and may be operated by the service provider or on behalf of the service provider. Host 1016 may host avariety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0199] As a whole, communication system 1000 of Figure 10 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0200] In some examples, telecommunication network 1002 is a cellular network that implements 3GPP standardized features. Accordingly, telecommunications network 1002 may support network slicing to provide different logical networks to different devices that are connected to telecommunication network 1002. For example, telecommunication network 1002 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.

[0201] In some examples, UEs 1012 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to access network 1004 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 1004. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e., being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0202] In the example, hub 1014 communicates with the access network 1004 to facilitate indirect communication between one or more UEs (e.g., 1012c and / or 1012d) and network nodes (e.g., 1010b). In some examples, hub 1014 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, hub 1014may be a broadband router enabling access to the core network 1006 for the UEs. As another example, hub 1014 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 1010, or by executable code, script, process, or other instructions in hub 1014. As another example, hub 1014 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, hub 1014 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, hub 1014 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 1014 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, hub 1014 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

[0203] Hub 1014 may have a constant / persistent or intermittent connection to the network node 1010b. Hub 1014 may also allow for a different communication scheme and / or schedule between hub 1014 and UEs (e.g., 1012c and / or 1012d), and between hub 1014 and core network 1006. In other examples, hub 1014 is connected to core network 1006 and / or one or more UEs via a wired connection. Moreover, hub 1014 may be configured to connect to an M2M service provider over access network 1004 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with network nodes 1010 while still connected via hub 1014 via a wired or wireless connection. In some embodiments, hub 1014 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to network node 1010b. In other embodiments, hub 1014 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 1010b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0204] In some embodiments, one or more UEs 1012 may be configured to perform operations attributed to a transmitting node and any of network nodes 1010 may be configured to perform operations attributed to a receiving node in various embodiments described above, including the exemplary methods shown in Figures 8-9. In other embodiments, one or more UEs 1012 may be configured to perform operations attributed to a receiving node and any of network nodes 1010 may be configured to perform operations attributed to a transmitting node in various embodiments described above, including the exemplary methods shown in Figures 8-9.

[0205] Figure 11 shows a UE 1100 in accordance with some embodiments. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wirelesscameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by 3GPP, including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0206] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0207] UE 1100 includes processing circuitry 1102 that is operatively coupled via bus 1104 to input / output interface 1106, power source 1108, memory 1110, communication interface 1112, and possibly one or more other components not explicitly shown. Certain UEs may utilize all or a subset of the components shown in Figure 11. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receiving nodes, etc.

[0208] Processing circuitry 1102 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in memory 1110. Processing circuitry 1102 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 1102 may include multiple central processing units (CPUs).

[0209] In the example, input / output interface 1106 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An inputdevice may allow a user to capture information into UE 1100. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0210] In some embodiments, power source 1108 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. Power source 1108 may further include power circuitry for delivering power from power source 1108 itself, and / or an external power source, to the various parts of UE 1100 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging power source 1108. Power circuitry may perform any formatting, converting, or other modification to the power from power source 1108 to make the power suitable for the respective components of UE 1100 to which power is supplied.

[0211] Memory 1110 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, memory 1110 includes one or more application programs 1114, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1116. Memory 1110 may store, for use by the UE 1100, any of a variety of various operating systems or combinations of operating systems.

[0212] Memory 1110 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as “SIM card.” Memory 1110 may allowUE 1100 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in memory 1110, which may be or comprise a device-readable storage medium.

[0213] Processing circuitry 1102 may be configured to communicate with an access network or other network using communication interface 1112. Communication interface 1112 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1122. Communication interface 1112 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include transmitter 1118 and / or receiving node 1120 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, transmitter 1118 and / or receiving node 1120 may be coupled to one or more antennas (e.g., 1122) and may share circuit components, software, or firmware, or alternatively be implemented separately.

[0214] In the illustrated embodiment, communication functions of the communication interface 1112 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0215] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1112, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., an alert is sent when moisture is detected), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0216] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wirelessconnection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0217] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 1100 shown in Figure 11.

[0218] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0219] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. Forexample, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0220] In some embodiments, UE 1100 may be configured to perform operations attributed to a transmitting node in various embodiments described above, including the exemplary method shown in Figure 8. In other embodiments, UE 1100 may be configured to perform operations attributed to a receiving node in various embodiments described above, including the exemplary methods shown in Figure 9.

[0221] Figure 12 shows a network node 1200 in accordance with some embodiments. Examples of network nodes include, but are not limited to, access points (e.g., radio access points) and base stations (e.g., radio base stations, Node Bs, eNBs, gNBs, etc.).

[0222] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0223] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSRBSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0224] Network node 1200 includes processing circuitry 1202, memory 1204, communication interface 1206, and power source 1208. Network node 1200 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which network node 1200 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, network node 1200 may be configured to support multiple radioaccess technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1204 for different RATs) and some components may be reused (e.g., a same antenna 1210 may be shared by different RATs). Network node 1200 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1200, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1200.

[0225] Processing circuitry 1202 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1200 components, such as the memory 1204, to provide network node 1200 functionality.

[0226] In some embodiments, processing circuitry 1202 includes a system on a chip (SOC). In some embodiments, processing circuitry 1202 includes one or more of radio frequency (RF) transceiver circuitry 1212 and baseband processing circuitry 1214. In some embodiments, RF transceiver circuitry 1212 and baseband processing circuitry 1214 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1212 and baseband processing circuitry 1214 may be on the same chip or set of chips, boards, or units.

[0227] Memory 1204 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by processing circuitry 1202. Memory 1204 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions (collectively denoted computer program product 1204a) capable of being executed by processing circuitry 1202 and utilized by network node 1200. Memory 1204 may be used to store any calculations made by processing circuitry 1202 and / or any data received via the communication interface 1206. In some embodiments, processing circuitry 1202 and memory 1204 can be integrated.Communication interface 1206 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, communication interface 1206 comprises port(s) / terminal(s) 1216 to send and receive data, for example to and from a network over a wired connection. Communication interface 1206 also includes radio frontend circuitry 1218 that may be coupled to, or in certain embodiments a part of, antenna 1210. Radio front-end circuitry 1218 comprises filters 1220 and amplifiers 1222. Radio front-end circuitry 1218 may be connected to antenna 1210 and processing circuitry 1202. The radio frontend circuitry may be configured to condition signals communicated between antenna 1210 and processing circuitry 1202. Radio front-end circuitry 1218 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1218 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1220 and / or amplifiers 1222. The radio signal may then be transmitted via antenna 1210. Similarly, when receiving data, antenna 1210 may collect radio signals which are then converted into digital data by radio front-end circuitry 1218. The digital data may be passed to processing circuitry 1202. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0228] In certain alternative embodiments, network node 1200 does not include separate radio front-end circuitry 1218, instead, processing circuitry 1202 includes radio front-end circuitry and is connected to antenna 1210. Similarly, in some embodiments, some or all of RF transceiver circuitry 1212 may be part of communication interface 1206. In still other embodiments, communication interface 1206 includes one or more ports or terminals 1216, radio front-end circuitry 1218, and RF transceiver circuitry 1212, as part of a radio unit (not shown), and communication interface 1206 communicates with baseband processing circuitry 1214, which is part of a digital unit (not shown).

[0229] Antenna 1210 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. Antenna 1210 may be coupled to radio front-end circuitry 1218 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, antenna 1210 is separate from network node 1200 and connectable to network node 1200 through an interface or port.

[0230] Antenna 1210, communication interface 1206, and / or processing circuitry 1202 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, antenna 1210, communication interface 1206, and / or processing circuitry 1202 may be configured to perform any transmitting operations described herein as being performed by the network node.Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0231] Power source 1208 provides power to various components of network node 1200 in a form suitable for the respective components (e.g., at voltage and current needed for each component). Power source 1208 may further comprise, or be coupled to, power management circuitry to supply the components of network node 1200 with power for performing the functionality described herein. For example, network node 1200 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of power source 1208. As a further example, power source 1208 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0232] Embodiments of network node 1200 may include additional components beyond those shown in Figure 12 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, network node 1200 may include user interface equipment to allow input of information into network node 1200 and to allow output of information from network node 1200. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 1200.

[0233] In some embodiments, network node 1200 may be configured to perform operations attributed to a transmitting node in various embodiments described above, including the exemplary method shown in Figure 8. In other embodiments, network node 1200 may be configured to perform operations attributed to a receiving node in various embodiments described above, including the exemplary methods shown in Figure 9.

[0234] Figure 13 is a block diagram illustrating a virtualization environment 1300 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1300 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodimentsin which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

[0235] Applications 1302 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1300 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein. In some embodiments, one or more virtual node 1302 may be configured to perform operations attributed to a transmitting node in various embodiments described above, including the exemplary method shown in Figure 8. In other embodiments, one or more virtual node 1302 may be configured to perform operations attributed to a receiving node in various embodiments described above, including the exemplary methods shown in Figure 9.

[0236] Hardware 1304 includes processing circuitry, memory that stores software and / or instructions (collective denoted computer program product 1304a) executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1306 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1308a-b (one or more of which may be generally referred to as VMs 1308), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. Virtualization layer 1306 may present a virtual operating platform that appears like networking hardware to VMs 1308.

[0237] VMs 1308 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1306. Different embodiments of the instance of a virtual appliance 1302 may be implemented on one or more of VMs 1308, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0238] In the context of NFV, each VM 1308 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each VM 1308, and that part of hardware 1304 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1308 on top of hardware 1304 and corresponds to application 1302.Hardware 1304 may be implemented in a standalone network node with generic or specific components. Hardware 1304 may implement some functions via virtualization. Alternatively, hardware 1304 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1310, which, among others, oversees lifecycle management of applications 1302. In some embodiments, hardware 1304 is coupled to one or more radio units that each include one or more transmitters and one or more receiving nodes that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1312 which may alternatively be used for communication between hardware nodes and radio units.

[0239] The foregoing merely illustrates the principles of the disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and procedures that, although not explicitly shown or described herein, embody the principles of the disclosure and can be thus within the spirit and scope of the disclosure. Various embodiments can be used together with one another, as well as interchangeably therewith, as should be understood by those having ordinary skill in the art.

[0240] The term unit, as used herein, can have conventional meaning in the field of electronics, electrical devices and / or electronic devices and can include, for example, electrical and / or electronic circuitry, devices, modules, processors, memories, logic solid state and / or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and / or displaying functions, and so on, as such as those that are described herein.

[0241] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and / or data communications protocolsas well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according to one or more embodiments of the present disclosure.

[0242] As described herein, device and / or apparatus can be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device or apparatus, instead of being hardware implemented, be implemented as a software module such as a computer program or a computer program product comprising executable software code portions for execution or being run on a processor. Furthermore, functionality of a device or apparatus can be implemented by any combination of hardware and software. A device or apparatus can also be regarded as an assembly of multiple devices and / or apparatuses, whether functionally in cooperation with or independently of each other. Moreover, devices and apparatuses can be implemented in a distributed fashion throughout a system, so long as the functionality of the device or apparatus is preserved. Such and similar principles are considered known to a skilled person.

[0243] 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.

[0244] In addition, certain terms used in the present disclosure, including the specification and drawings, can be used synonymously in certain instances (e.g., “data” and “information”). It should be understood that although such terms can be used synonymously herein, there can be instances when such terms are not intended to not be used synonymously.

Claims

CLAIMS1. A method performed by a transmitting node configured to operate in a radio access network, RAN, the method comprising:receiving (820) a plurality of sets of protocol data units, PDUs, generated by an application for transmission to a receiving node in the RAN;transmitting (830) the plurality of sets of PDUs to the receiving node; andsending (840), to the receiving node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application, wherein the application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality:a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; anda second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

2. The method of claim 1, further comprising receiving from the receiving node a configuration for reporting application observability information, wherein the application observability information is sent to the receiving node in accordance with the configuration.

3. The method of claim 2, wherein the configuration includes or indicates one or more of the following:a PDU set delay budget, PSDB, requirement for the application;a PDU set error rate, PSER, requirement for the application;which application observability information to report;a quantity of PDU sets for which application observability information should be reported;a duration between periodic application observability information reports; and one or more aperiodic reporting conditions.

4. The method of any of claims 1-3, wherein:the transmitting node determines Tl but not T2 for each PDU set of the plurality of PDU sets; andthe application observability information includes a representation of T1 determined for each PDU set.

5. The method of claim 4, wherein for each PDU set, the representation of T1 is included in a header of a protocol service data unit, SDU, that carries at least a portion of one or more PDUs of the PDU set.

6. The method of claim 5, wherein:each PDU set of the plurality of PDU sets is received together with one or more of the following associated information: quality-of-service, QoS, flow identifier; PDU set sequence number; sequence numbers of each PDU of the PDU set; indicator of end PDU of the PDU set; PDU set importance indicator; and PDU set size; and at least one of the associated information is included in the header of the SDU together with the representation of T1.

7. The method of any of claims 4-6, wherein the representation of T1 includes or indicates one or more of the following parameters that identify a timing event on a radio interface between the transmitting node and the receiving node: hyperframe number, subframe number, slot number, and symbol number.

8. The method of claim 7, wherein the subframe number is represented by a first plurality of bits, the slot number is represented by a second plurality of bits, the symbol number is represented by a third plurality of bits, and the representation of T1 includes lowest-order subsets of at least one of the first, second, and third pluralities of bits.

9. The method of any of claims 4-8, further comprising receiving one or more of the following application observability information from the receiving node:for each of the PDU sets, an indication of whether a difference, T2-T1, for the PDU set met a PDU set delay budget, PSDB, requirement for the application; one or more statistics for the differences, T2-T1, for the plurality of PDU sets;one or more statistics related to how many PDUs of each PDU set met the PSDB; an estimated PDU set error rate, PSER, for the plurality of PDU sets; andan indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.

10. The method of claim 9, further comprising sending to the receiving node a further configuration for reporting application observability information, wherein the application observability information is received from the receiving node in accordance with the further configuration.

11. The method of claim 1 , wherein:the transmitting node determines T1 and T2 for each PDU set of the plurality of PDU sets; andthe method further comprises, for each PDU set, determining whether a difference, T2- Tl, meets a PDU set delay budget, PSDB, requirement for the application.

12. The method of claim 11, further comprising, when it is determined for a PDU set that T2-T1 does not meet the PSDB requirement, determining a portion of the PDU set whose transmission by the transmitting node met the PSDB requirement.

13. The method of any of claims 11-12, further comprising:estimating a PDU set error rate, PSER, based on a ratio of the following: how many PDU sets of the plurality for which T2-T1 was determined not to meet the PSDB requirement, to a total number of PDU sets of the plurality; and determining whether the estimated PSER meets a PSER requirement for the application.

14. The method of any of claims 11-13, wherein the application observability information includes one or more of the following:for each of the PDU sets, an indication of whether the difference, T2-T1, determined for the PDU set met the PSDB requirement for the application;one or more statistics for the differences, T2-T1, determined for the plurality of PDU sets;one or more statistics related to how many PDUs of each PDU set met the PSDB; an estimated PDU set error rate, PSER, for the plurality of PDU sets; andan indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.

15. The method of any of claims 11-14, wherein the application observability information is sent in response to one of the following: receiving a request from the receiving node forapplication observability information, expiration of a periodic reporting timer, or one or more aperiodic reporting conditions being met.

16. The method of any of claims 11-15, wherein:each PDU set of the plurality of PDU sets is received together with one or more of the following associated information: quality-of-service, QoS, flow identifier; PDU set sequence number; sequence numbers of each PDU of the PDU set; indicator of end PDU of the PDU set; PDU set importance indicator; and PDU set size; and T2 for each PDU set is determined as when the last-transmitted PDU of the PDU set was transmitted by the transmitting node, based on the associated information for the PDU set.

17. The method of claim 16, wherein T2 for each PDU set is determined further based on timing of a final retransmission of the last-transmitted PDU of the PDU set.

18. The method of any of claims 11-15, wherein T2 for each PDU set is determined as when the last-transmitted PDU of the PDU set was received by the receiving node, based one of the following:when the transmitting node received a hybrid ARQ acknowledgement associated with the last-transmitted PDU of the PDU set;when a retransmission timer associated with the last-transmitted PDU of the PDU set expires; ora duration that is long enough to ensure any retransmission of the last-transmitted PDU of the PDU set has been sent.

19. The method of any of claims 1-18, wherein one of the following applies:the transmitting node is a user equipment, UE, and the receiving node is a RAN node; or the transmitting node is a RAN node and the receiving node is a UE.

20. A method for a receiving node configured to operate in a radio access network, RAN, the method comprising:receiving (920), from a transmitting node in the RAN, a plurality of sets of protocol data units, PDUs, generated by an application; andreceiving (930), from the transmitting node, application observability information related to whether the transmission of the plurality of PDU sets met one or moreperformance requirements for the application, wherein the received application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality:a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; anda second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

21. The method of claim 20, further comprising sending to the transmitting node a configuration for reporting application observability information, wherein the application observability information is received from the transmitting node in accordance with the configuration.

22. The method of claim 21, wherein the configuration includes or indicates one or more of the following:a PDU set delay budget, PSDB, requirement for the application;a PDU set error rate, PSER, requirement for the application;which application observability information to report;a quantity of PDU sets for which application observability information should be reported;a duration between periodic application observability information reports; and one or more aperiodic reporting conditions.

23. The method of any of claims 20-22, wherein the received application observability information includes a representation of Tl determined by the transmitting node.

24. The method of claim 23, further comprising, for each PDU set:determining the second time, T2, when a last-transmitted PDU of the PDU set was received by the receiving node; anddetermining whether a difference, T2-T1, meets a PDU set delay budget, PSDB, requirement for the application.

25. The method of claim 24, further comprising, when it is determined that T2-T1 for a PDU set does not meet the PSDB requirement, determining a portion of the PDU set whose reception by the receiving node met the PSDB requirement.

26. The method of any of claims 24-25, further comprising:estimating a PDU set error rate, PSER, based on a ratio of the following: how many PDU sets of the plurality for which T2-T1 was determined not to meet the PSDB requirement, to a total number of PDU sets of the plurality; anddetermining whether the estimated PSER meets a PSER requirement for the application.

27. The method of any of claims 24-26, wherein for each PDU set, the representation of T1 is included in a header of a protocol service data unit, SDU, that carries at least a portion of one or more PDUs of the PDU set.

28. The method of claim 27, wherein for each PDU set of the plurality:at least one of the following associated information is included in the header of the SDU together with the representation of Tl: quality-of-service, QoS, flow identifier; PDU set sequence number; sequence numbers of each PDU of the PDU set; indicator of end PDU of the PDU set; PDU set importance indicator; and PDU set size; andT2 is determined further based on the associated information for the PDU set.

29. The method of any of claims 24-28, wherein T2 for each PDU set is determined further based on when a final retransmission of the last-transmitted PDU of the PDU set is received by the receiving node.

30. The method of any of claims 24-29, further comprising sending one or more of the following application observability information to the transmitting node:for each of the PDU sets, an indication of whether the difference, T2-T1, determined for the PDU set met the PSDB requirement for the application;one or more statistics for the differences, T2-T1, determined for the plurality of PDU sets;one or more statistics related to how many PDUs of each PDU set met the PSDB; an estimated PDU set error rate, PSER, for the plurality of PDU sets; andan indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.

31. The method of claim 30, further comprising receiving from the transmitting node a further configuration for reporting application observability information, wherein the application observability information is sent to the transmitting node in accordance with the further configuration.

32. The method of any of claims 23-31, wherein the representation of T1 includes or indicates one or more of the following parameters that identify a timing event on a radio interface between the transmitting node and the receiving node: hyperframe number, subframe number, slot number, and symbol number.

33. The method of claim 32, wherein the subframe number is represented by a first plurality of bits, the slot number is represented by a second plurality of bits, the symbol number is represented by a third plurality of bits, and the representation of T1 includes lowest-order subsets of at least one of the first, second, and third pluralities of bits.

34. The method of any of claims 20-22, wherein the received application observability information includes one or more of the following:for each of the PDU sets, an indication of whether a difference, T2-T1, determined for the PDU set met a PDU set delay budget, PSDB, requirement for the application; one or more statistics for the differences, T2-T1, determined for the plurality of PDU sets;one or more statistics related to how many PDUs of each PDU set met the PSDB; an estimated PDU set error rate, PSER, for the plurality of PDU sets; andan indication of whether an estimated PSER for the plurality of PDU sets met a PSER requirement for the application.

35. The method of claim 34, wherein the application observability information is received in response to one of the following: sending a request to the transmitting node for application observability information, expiration of a periodic reporting timer at the transmitting node, or one or more aperiodic reporting conditions being met at the transmitting node.

36. The method of any of claims 20-35, wherein one of the following applies:the transmitting node is a user equipment, UE, and the receiving node is a RAN node; or the transmitting node is a RAN node and the receiving node is a UE.

31. A transmitting node (100, 205, 210, 220, 310, 320, 710, 1010, 1012, 1100, 1200, 1302) configured to operate in a radio access network, RAN (199, 299, 904), the transmitting node comprising:communication interface circuitry (1112, 1206, 1304) configured to communicate with a receiving node (100, 205, 210, 220, 310, 320, 720, 1010, 1012, 1100, 1200, 1302) in the RAN; andprocessing circuitry (1102, 1202, 1304) operatively coupled to the communication interface circuitry, wherein the processing circuitry and the communication interface circuitry are configured to:receive a plurality of sets of protocol data units, PDUs, generated by an application for transmission to the receiving node;transmit the plurality of sets of PDUs to the receiving node; and send, to the receiving node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application, wherein the application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality: a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; anda second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

38. The transmitting node of claim 37, wherein the processing circuitry and the communication interface circuitry are further configured to perform operations corresponding to any of the methods of claims 2-19.

39. A transmitting node (100, 205, 210, 220, 310, 320, 710, 1010, 1012, 1100, 1200, 1302) configured to operate in a radio access network, RAN (199, 299, 904), the transmitting node being further configured to:receive a plurality of sets of protocol data units, PDUs, generated by an application for transmission to a receiving node (100, 205, 210, 220, 310, 320, 720, 1010, 1012, 1100, 1200, 1302) in the RAN;transmit the plurality of sets of PDUs to the receiving node; andsend, to the receiving node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application, wherein the application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality:a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; anda second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

40. The transmitting node of claim 39, being further configured to perform operations corresponding to any of the methods of claims 2-19.

41. Anon-transitory, computer-readable medium (1110, 1204, 1304) storing computerexecutable instructions that, when executed by processing circuitry (1102, 1202, 1304) of a transmitting node (100, 205, 210, 220, 310, 320, 710, 1010, 1012, 1100, 1200, 1302) configured to operate in a radio access network, RAN (199, 299, 904), configure the transmitting node to perform operations corresponding to any of the methods of claims 1-19.

42. A computer program product (1014, 1104a, 1204a) comprising computer-executable instructions that, when executed by processing circuitry (1102, 1202, 1304) of a transmitting node (100, 205, 210, 220, 310, 320, 710, 1010, 1012, 1100, 1200, 1302) configured to operate in a radio access network, RAN (199, 299, 904), configure the transmitting node to perform operations corresponding to any of the methods of claims 1-19.

43. A receiving node (100, 205, 210, 220, 310, 320, 720, 1010, 1012, 1100, 1200, 1302) configured to operate in a radio access network, RAN (199, 299, 904), the receiving node comprising:communication interface circuitry (1012, 1106, 1204) configured to communicate with a transmitting node (100, 205, 210, 220, 310, 320, 710, 1010, 1012, 1100, 1200, 1302) in the RAN; andprocessing circuitry (1002, 1102, 1204) operatively coupled to the communication interface circuitry, wherein the processing circuitry and the communication interface circuitry are configured to:receive, from the transmitting node, a plurality of sets of protocol data units, PDUs, generated by an application; andreceive, from the transmitting node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application, wherein the received application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality:a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; anda second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

44. The receiving node of claim 43, wherein the processing circuitry and the communication interface circuitry are further configured to perform operations corresponding to any of the methods of claims 21-36.

45. A receiving node (100, 205, 210, 220, 310, 320, 720, 1010, 1012, 1100, 1200, 1302) configured to operate in a radio access network, RAN (199, 299, 904), the receiving node being further configured to:receive, from a transmitting node (100, 205, 210, 220, 310, 320, 710, 1010, 1012, 1100, 1200, 1302) in the RAN, a plurality of sets of protocol data units, PDUs, generated by an application; andreceive, from the transmitting node, application observability information related to whether the transmission of the plurality of PDU sets met one or more performance requirements for the application, wherein the received application observability information is based on at least one of the following determined by the transmitting node for each PDU set of the plurality:a first time, Tl, when a first-received PDU of the PDU set was received by the transmitting node from the application; anda second time, T2, when a last-transmitted PDU of the PDU set was transmitted by the transmitting node or received by the receiving node.

46. The receiving node of claim 45, being further configured to perform operations corresponding to any of the methods of claims 21-36.

47. A non-transitory, computer-readable medium (1110, 1204, 1304) storing computer-executable instructions that, when executed by processing circuitry (1002, 1102, 1204) of a receiving node (100, 205, 210, 220, 310, 320, 720, 1010, 1012, 1100, 1200, 1302) configured to operate in a radio access network, RAN (199, 299, 904), configure the receiving node to perform operations corresponding to any of the methods of claims 20-36.

48. A computer program product (1114, 1204a, 1304a) comprising computer-executable instructions that, when executed by processing circuitry (1002, 1102, 1204) of a receiving node (100, 205, 210, 220, 310, 320, 720, 1010, 1012, 1100, 1200, 1302) configured to operate in a radio access network, RAN (199, 299, 904), configure the receiving node to perform operations corresponding to any of the methods of claims 20-36.

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