Packet data convergence protocol packet sequence number gap reporting

Abstract

A communication node (12) for use in a communication network (10). The communication node (12) stores multiple Packet Data Convergence Protocol, PDCP, packets (24) in a transmit buffer (26). The communication node (12) discards a PDCP packet (24) from the transmit buffer (26). The communication node (12) makes a decision about whether or not the discarding of the PDCP packet (24) is to trigger transmission of a PDCP SN gap report (40). The decision is made based on one or more triggering criterions. In some embodiments, the one or more triggering criterions include one or more characteristics of a PDU Set (22) to which the discarded PDCP packet (24) belongs and / or one or more characteristics of a PDU Set (22) to which another PDCP packet (24) stored in the transmit buffer (26) belongs. The communication node (12) triggers or does not trigger transmission of the PDCP SN gap report (40) according to the decision.

Description

[0001] PACKET DATA CONVERGENCE PROTOCOL PACKET SEQUENCE NUMBER GAP REPORTING

[0002] TECHNICAL FIELD

[0003] The present application relates generally to a communication network, and relates more particularly to reporting of a gap in sequence numbers of Packet Data Convergence Protocol (PDCP) packets in such a network.

[0004] BACKGROUND

[0005] The Packet Data Convergence Protocol (PDCP) sublayer serves several functions in communication. A packet that the PDCP layer receives from a higher protocol layer for transmission is referred to as a Service Data Unit (SDU). From this SDU, the PDCP layer forms one or more other packets referred to as Protocol Data Units (PDUs) for sending to a lower protocol layer, for further processing and transmission. Each PDU encapsulates at least some of the payload of the SDU with a PDCP header.

[0006] One of the tasks of PDCP is to ensure the reliable transmission of data by buffering transmitted packets, e.g., PDCP Service Data Units (SDUs). In simple terms, it holds onto these packets temporarily so that they can be resent if not received correctly the first time.

[0007] More particularly, PDCP uses status reports to communicate which SDUs were successfully received and which ones were not. If some SDUs were missed, they are resent to ensure complete transmission. To manage this process effectively, the transmitting PDCP entity needs a buffer to store the SDUs temporarily. However, this buffering introduces challenges, such as knowing when to discard or remove an SDU from the buffer. This decision might be based on factors like buffer overflow or when an SDU becomes too old to be useful according to its Quality of Service (QoS) profile. To address this, PDCP employs a discard timer. When an SDU is placed in the buffer for transmission, a countdown timer (referred to as a discard timer) starts running. If confirmation of successful delivery isn't received before the discard timer expires, the SDU is discarded from the buffer. This ensures that the buffer doesn't become cluttered with stale or unneeded data. Additionally, PDCP may discard an SDU if it receives confirmation of successful delivery through a status report.

[0008] With each PDCP SDU assigned a sequence number (SN), PDCP discard in some cases can cause gaps in the SNs received as the PDCP receiver. To account for this, the PDCP transmitter can send a so-called PDCP SN gap report to the PDCP receiver. Using this report, the PDCP transmitter can inform the PDCP receiver of missing PDCP SN numbers, i.e. the PDCP SDUs that have been discarded and thus will not be transmitted. The information about missing SN(s) will enable the receiver side to move the receiving window forward faster (i.e., reduce the waiting time of reordering timers) and allow for faster delivery of received packets to higher layers. Upon receiving the PDCP SN gap report, the receiver state variables (RX_NEXT, RX_DELIV and RX_REORD) are updated.

[0009] Challenges arise with the PDCP SN gap report under some contexts, though. In this regard, some known approaches apply the same PDCP discard timer to multiple SDUs that carry the payload of one unit of information at the application layer, referred to as a PDU Set. Where the application layer unit of information represents a video frame, for example, the PDU Set may represent multiple PDCP SDUs conveying that video frame. Applying PDCP discard on a PDU Set basis may account for the reality that expiration of a PDCP discard timer for one SDU in the PDU Set means that the whole PDU Set is no longer useful and can be discarded in full. Exploiting PDU Sets in this way improves PDCP discard because it improves radio resource conservation by avoiding wasting radio resources on transmitting data that has become useless. Additionally advantages can be realized by differentiating PDU Sets on the basis of how important they are to a quality of service (QoS) flow, e.g., using a PDU Set Importance (PSI) indicator accompanying each PDU Set. With this, PDCP discard may be performed on a PDU Set level, e.g., so as to favor discarding less important PDU Sets.

[0010] SUMMARY

[0011] Some embodiments herein recognize that problems with PDCP SN gap reports can arise in scenarios that exploit the PDU Set and PSI discarding features. In particular, there can be scenarios where the discard timer of low importance PDU Sets is shorter than the high importance PDU Sets. The low importance PDU Sets may have arrived later to the buffer than the high importance PDU Sets but may still expire the discard timer earlier. The PDU Sets may also be interleaved in the transmit buffer. This creates a scenario that a PDCP SN Gap report is triggered for the discard of the SDUs belonging to the low importance PDU Set while there are still SDUs to be transmitted with lower SN belonging to a higher importance PDU Set.

[0012] The reception of such PDCP SN Gap report can in these cases creates problems for the receiver by unnecessarily moving the receiving window forward (RX_NEXT). In some cases, this can make the later transmitted SDUs with lower SN to be ignored or discarded by the receiver. This not only prevents the packets to be not submitted to upper layers but also rendering the packets already stored in the receive buffer outdated due to reordering timer delays. This may occur for example if the traffic has short packet delay budgets, e.g., as may be the case for extended Reality (XR) traffic. In addition, it could also lead to a loss of synchronization between the Tx and Rx windows.

[0013] According to some embodiments herein, a communication node decides whether or not the discarding of a PDCP packet is to trigger transmission of a PDCP SN gap report on the basis of certain criterion(s). Such criterion(s) may include characteristic(s) of a PDU Set to which the discarded PDCP packet belongs and / or characteristic(s) of a PDU Set to which another PDCP packet stored in the transmit buffer belongs. For example, the communication node may decide not to trigger a PDCP SN gap report, even if discarding of the PDCP packet caused an SN gap, if the discarded PDCP packet belongs to a low importance PDU Set and / or if another PDCP packet still stored in the transmit buffer belongs to a high importance PDU Set. By avoiding sending a PDCP SN gap report in these and other cases, the communication node may preserve, within the PDCP receiver’s receiver window, any PDCP packets that are still in the transmit buffer and that belong to a high importance PDU Set. Other embodiments herein generate a PDCP SN gap report’s contents in such a way that addresses these and other issues. By triggering and / or generating the content of a PDCP SN gap report in these and other ways, some embodiments herein advantageously allow for assigning different PDU Sets different importance levels and different discard timer values for PDU Set level discarding, while guarding against the possibility that discarding low importance PDU Sets would cause high importance PDU Sets to be prematurely left behind outside of the receiving window.

[0014] More particularly, embodiments herein include a method performed by a communication node for use in a communication network. The method comprises storing multiple Packet Data Convergence Protocol, PDCP, packets in a transmit buffer of the communication node, and discarding a PDCP packet from the transmit buffer. The method also comprises making a decision about whether or not the discarding of the PDCP packet is to trigger transmission of a PDCP SN gap report that reports one or more gaps in SNs of PDCP packets from the communication node, wherein the decision is made based on one or more triggering criterions. In some embodiments, the one or more triggering criterions include at least one or more characteristics of a PDU Set to which the discarded PDCP packet belongs and / or one or more characteristics of a PDU Set to which another PDCP packet stored in the transmit buffer belongs. In other embodiments, the one or more triggering criterions include at least a number of PDU Sets, and / or a number of types of PDU Sets, to which the multiple PDCP packets belong. In yet other embodiments, the one or more triggering criterions include at least a number of PDU Sets, and / or a number of types of PDU Sets, to which one or more PDCP packets remaining in the transmit buffer after discarding the PDCP packet belong. In still yet other embodiments, the one or more triggering criterions include at least a value of a discard timer for another PDCP packet stored in the transmit buffer. The method also comprises triggering or not triggering transmission of the PDCP SN gap report according to the decision.

[0015] In some embodiments, the method further comprises transmitting the PDCP SN gap report responsive to triggering transmission of the PDCP SN gap report. Other embodiments herein include a method performed by a communication node for use in a communication network. The method comprises discarding one or more Packet Data Convergence Protocol, PDCP, packets from a transmit buffer within which is stored multiple PDCP packets, and based on said discarding, generating a PDCP sequence number, SN, gap report that reports one or more gaps in SNs of PDCP packets from the communication node, wherein said generating comprises determining a content of the PDCP SN gap report based on one or more content determination criterions. In some embodiments, the one or more content determination criterions include at least, for each of one or more of the one or more discarded PDCP packets, one or more characteristics of a PDU Set to which the discarded PDCP packet belongs. In some embodiments, the one or more content determination criterions include at least, for each of one or more non-discarded PDCP packets that are not discarded from the transmit buffer, one or more characteristics of a PDU Set to which the non-discarded PDCP packet belongs. In some embodiments, the one or more content determination criterions include at least, for each of one or more nondiscarded PDCP packets that are not discarded from the transmit buffer, a value of a discard timer for the non-discarded PDCP packet. In some embodiments, the one or more content determination criterions include at least a number of PDU Sets, and / or a number of types of PDU Sets, to which the multiple PDCP packets belong. In some embodiments, the one or more content determination criterions include at least a number of PDU Sets, and / or a number of types of PDU Sets, to which one or more non-discarded PDCP packets that are not discarded from the transmit buffer belong. The method also comprises transmitting the generated PDCP SN gap report.

[0016] Embodiments herein also include corresponding apparatus, computer programs, and carriers of those computer programs.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a block diagram of a communication network according to some embodiments.

[0019] Figure 2 is a block diagram of transmission processing at a Packet Data Convergence Protocol (PDCP) layer of a communication node according to some embodiments.

[0020] Figure 3 shows an example of frame latency measured over radio access network according to some embodiments.

[0021] Figure 4 shows an example of the cumulative distribution functions of the number of transport blocks according to some embodiments.

[0022] Figure 5 illustrates exemplary characteristics of XR traffic arrival versus typical webbrowsing and VoIP traffic according to some embodiments. Figure 6 illustrates an example of problems with a PDCP SN Gap report according to some embodiments.

[0023] Figure 7 is a block diagram of an example with respect to the characteristic of the PDU set according to some embodiments.

[0024] Figure 8 is a block diagram of an example of the state variables at the receiver being adjusted according to some embodiments.

[0025] Figure 9 is a logic flow diagram of a method performed by a communication node for use in a communication network in accordance with particular embodiments.

[0026] Figure 10 is a logic flow diagram of a method performed by a communication node for use in a communication network in accordance with other particular embodiments.

[0027] Figure 11 is a block diagram of a communication device according to some embodiments.

[0028] Figure 12 is a block diagram of a network node according to some embodiments.

[0029] Figure 13 is a block diagram of a communication system according to some embodiments.

[0030] Figure 14 is a block diagram of a UE according to some embodiments.

[0031] Figure 15 is a block diagram of a network node according to other embodiments.

[0032] Figure 16 is a block diagram of a virtualization environment according to other embodiments

[0033] DETAILED DESCRIPTION

[0034] Figure 1 shows a communication network 10 according to some embodiments. The communication network 10 provides communication service to one or more communication devices 12A. In this context, a network node 12B of the communication network 10 may perform downlink transmission(s) to a communication device 12A over a downlink 14D and / or a communication device 12A may perform uplink transmission(s) to a network node 12B over an uplink 14U. Alternatively or additionally, communication devices 12A may perform sidelink transmission(s) to one another over a sidelink 14S which does not traverse any network node 12B of the communication network 10. As used herein, then, both a communication device 12A and a network node 12B may be referred to generally as a communication node 12.

[0035] In this context, Figure 2 shows transmission processing at a Packet Data Convergence Protocol (PDCP) layer 16P of a communication node 12, whether for an uplink transmission over an uplink 14U, a downlink transmission over a downlink 14D, or a sidelink transmission over a sidelink 14S. The transmission processing at the PDCP layer 16P may for instance be performed by a PDCP entity, one of which is shown as an example. As shown, the communication node 12 implements a transmission protocol stack that includes the PDCP layer 16P as well as one or more other layers, e.g., an application layer 16A that is higher than the PDCP layer 16P and one or more lower layers 16L that are lower than the PDCP layer 16P in the protocol stack. The PDCP layer 16P receives PDCP packets referred to as PDCP Service Data Units (SDUs) from a higher layer in the protocol stack, performs PDCP processing 30 on those PDCP SDUs, and then transmits PDCP packets referred to as PDCP Protocol Data Units (PDUs) to a lower layer 16L in the protocol stack.

[0036] While the PDCP layer 16P waits for confirmation that a PDCP SDU was received successfully, the communication node 12 stores the PDCP SDU in a transmit buffer 26 and starts a countdown timer referred to as a discard timer. If the communication node 12 receives confirmation that the PDCP SDU was received successfully, the communication node 12 can go ahead and discard the PDCP SDU by removing it from the buffer 26. Otherwise, the communication node 12 may continue to store the PDCU SDU in the buffer 26 for as long as the discard timer is running. Once the discard timer expires, though, the communication node 12 discards the PDCP SDU even if the communication node 12 has not received confirmation of successful reception.

[0037] Figure 2 shows this for two example PDCP SDUs received at the PDCP layer 16P, including PDCP SDU 24-1 and PDCP 24-2. The communication node 12 receives PDCP SDU 24-1 , performs PDCP processing 30 on that PDCP SDU 24-1 to produce one or more corresponding PDCP PDUs 32-1 , and transmits the corresponding PDCP PDUs 32-1 to lower layer(s) 16L. While waiting for confirmation that the PDCP SDU 24-1 was received successfully, the communication node 12 stores PDCP SDU 24-1 in the buffer 26 and starts a discard timer 28-1 for the PDCP SDU 24-1 to govern PDCP discard of the PDCP SDU 24-1.

[0038] Similarly, the communication node 12 receives PDCP SDU 24-2, performs PDCP processing 30 on that PDCP SDU 24-2 to produce one or more corresponding PDCP PDUs 32-2, and transmits the corresponding PDCP PDUs 32-2 to lower layer(s) 16L. While waiting for confirmation that the PDCP SDU 24-2 was received successfully, the communication node 12 stores PDCP SDU 24-2 in the buffer 26 and starts a discard timer 28-2 for the PDCP SDU 24-2 to govern PDCP discard of the PDCP SDU 24-2.

[0039] In this context, then, the communication node 12 stores multiple PDCP packets 24 in the transmit buffer 26. At some point the communication node 12 discards a PDCP packet 24 from the transmit buffer 26, e.g., upon the expiration of a discard timer 28 governing that PDCP packet 24. According to some embodiments, the communication node 12 then makes a decision about whether or not the discarding of the PDCP packet 24 is to trigger transmission of a PDCP SN gap report 40. A PDCP SN gap report 40 reports one or more gaps in sequence numbers (SNs) of PDCP packets 24 from the communication node 12. According to some embodiments, the communication node 12 makes this decision based on one or more triggering criterions. The triggering criterion(s) may include, for example, characteristic(s) of a PDU Set 22 to which the discarded PDCP packet 24 belongs and / or characteristic(s) of a PDU Set to which another PDCP packet 24 stored in the transmit buffer 26 belongs. Alternatively or additionally, the triggering condition(s) may include a number of PDU Sets 22, and / or a number of types of PDU Sets 22, to which the multiple PDCP packets 24 belong. Alternatively or additionally, the triggering condition(s) may include a number of PDU Sets 22, and / or a number of types of PDU Sets 22, to which one or more PDCP packets 24 remaining in the transmit buffer 26 after discarding the PDCP packet belong. Alternatively or additionally, the triggering condition(s) may include a value of a discard timer 28 for another PDCP packet 24 stored in the transmit buffer 26.

[0040] Alternatively or additionally, the triggering conditions may include a value of the discard timer 28 governing the discarded PDCP packet 24, i.e., a value with which the discard timer 28 was started before its expiry. In one such embodiment, discard timers 28 for PDCP packets 24 belonging to PDU Sets 22 with different characteristics (e.g., importance levels) may be started with different values. For example, the discard timer 28 for a PDCP packet 24 belonging to a PDU Set 22 with a higher importance may be started with a lower value than the discard timer 28 for a PDCP packet 24 belonging to a PDU Set 22 with a lower importance.

[0041] Having made this decision, the communication node 12 triggers or does not trigger transmission of the PDCP SN gap report 40 according to the decision.

[0042] Note also that while some embodiments above have exemplified the decision about whether to transmit a PDCP SN gap report as being triggered by the discarding of a single PDCP packet, that decision may generally be triggered by the discarding of one or more PDCP packets, e.g., in the same PDU Set or across PDU Sets.

[0043] Additional aspects of these triggering embodiments are enumerated herein as Embodiments A1-A31 below.

[0044] Other embodiments herein concern how to generate the content of the PDCP SN gap report 40. In these embodiments, the communication node 12 discards one or more PDCP packets from the transmit buffer 26 within which is stored multiple PDCP packets. Based on this discarding, the communication node 12 generates a PDCP SN gap report 40. To do so, the communication node 12 determines the content of the PDCP SN gap report 40 based on content determination criterion(s).

[0045] The content determination criterion(s) may include, for each of one or more of the one or more discarded PDCP packets, one or more characteristics of a PDU Set to which the discarded PDCP packet belongs. Alternatively or additionally, the content determination criterion(s) may include, for each of one or more non-discarded PDCP packets that are not discarded from the transmit buffer, one or more characteristics of a PDU Set to which the non-discarded PDCP packet belongs. Alternatively or additionally, the content determination criterion(s) may include, for each of one or more non-discarded PDCP packets that are not discarded from the transmit buffer, a value of a discard timer for the non-discarded PDCP packet. Alternatively or additionally, the content determination criterion(s) may include a number of PDU Sets, and / or a number of types of PDU Sets, to which the multiple PDCP packets belong. Alternatively or additionally, the content determination criterion(s) may include a number of PDU Sets, and / or a number of types of PDU Sets, to which one or more non-discarded PDCP packets that are not discarded from the transmit buffer belong; and

[0046] Having generated the PDCP SN gap report 40, the communication node 12 transmits the generated PDCP SN gap report 40.

[0047] Additional aspects of these triggering embodiments are enumerated herein as Embodiments AAA1-AAA32 below.

[0048] Note that while embodiments above were exemplified by referring to PDCP SDUs, embodiments herein may be applicable to any type of PDCP packet, whether a PDCP SDU or a PDCP PDU (e.g., corresponding to the PDCP SDU).

[0049] Some embodiments herein are applicable in the following context, where the communication network 10 may be exemplified as a 5G network, the communication node 12 may be exemplified as a user equipment (UE) or a radio network node such as a gNB, and a PDCP packet may be exemplified as a PDCP SDU or PDU.

[0050] Some embodiments in this regard are applicable to 5G. 5G is the fifth generation of mobile communications, addressing a wide range of use cases from enhanced mobile broadband (eMBB) to ultra-reliable low-latency communications (URLLC) to massive machine type communications (mMTC). 5G includes the New Radio (NR) access stratum interface and the 5G Core Network (5GC). The NR physical and higher layers are reusing parts of the LTE specification, and to that add needed components when motivated by new use cases.

[0051] Some embodiments herein are applicable for low-latency high-rate applications such as extended Reality (XR) and cloud gaming. XR may refer to all real-and-virtual combined environments and human-machine interactions generated by computer technology and wearables. It is an umbrella term for different types of realities including Virtual reality (VR), Augmented reality (AR), Mixed reality (MR), and the areas interpolated among them. The levels of virtuality range from partially sensory inputs to fully immersive VR. Some embodiments herein may be applicable for 5G NR as designed to support applications demanding high rate and low latency in line with the requirements posed by the support of XR and cloud gaming applications in NR networks. Low-latency high-rate XR applications

[0052] The low-latency applications like XR and cloud gaming require bounded latency, not necessarily ultra-low latency. The end-to-end latency budget may be in the range of 20-80 ms, which needs to be distributed over several components including application processing latency, transport latency, radio link latency, etc. For these applications, short transmission time intervals (TTIs) or mini-slots targeting ultra-low latency may not be effective.

[0053] Figure 3 shows an example of frame latency measured over radio access network (RAN), excluding application and core network latencies. It can be seen that there exist frame latency spikes in RAN. The sources for the latency spikes may include queuing delay, time-varying radio environments, time-varying frame sizes, among others. Tools that can help to remove latency spikes are beneficial to enable better 5G support for this type of traffic.

[0054] In addition to bounded latency requirements, applications like XR and cloud gaming also require high-rate transmission. This can be seen from the large frame sizes originated from this type of traffic. The typical frame sizes may range from tens of kilobytes to hundreds of kilobytes. The frame arrival rates may be 60 or 120 frames per second (fps). As a concrete example, a frame size of 100 kilobytes and a frame arrival rate of 120 fps can lead to a rate requirement of 95.8 Mbps.

[0055] A large video frame is usually fragmented into smaller IP packets and transmitted as several transport blocks (TBs) over several TTIs in RAN. Figure 4 shows an example of the cumulative distribution functions of the number of transport blocks required to deliver a video frame with size ranging from 20 KB to 300 KB. For example, Figure 4 shows that for delivering the frames with a size of 200 KB each, the median number of needed TBs is 5.

[0056] The characteristics of XR traffic arrival are quite distinct from typical web-browsing and VoIP traffic as shown in Figure 5. It is well expected that the arrival time is quasi- periodic and largely predictable as Voice over Internet Protocol (VoIP). However, its data size is order of magnitude larger than VoIP, as discussed above. In addition, similar to webbrowsing, the data size is different at every application PDU arrival instance due to dynamics of contents and human motion.

[0057] As mentioned above, many XR applications will generate traffic periodically with a variable size. When the application packet enters the internet, the initial packet may be transmitted into a single PDU in the network or may be segmented several PDUs. One application packet could, for instance, correspond to one or several IP packets.

[0058] Internet Protocol (IP) packets will arrive to the Packet Data Convergence Protocol (PDCP) layer, i.e., PDCP Service Data Units (SDUs), and the PDCP layer will create PDCP Protocol Data Units (PDUs) and will deliver them to lower layers. When an IP packet arrives to PDCP, the PDCP layer starts a PDCP discard timer. When this timer expires, the PDCP discards the PDCP SDU as well as the corresponding PDCP Data PDU. If the PDCP PDU was delivered to lower layers, PDCP indicates the discard to lower layers. Lower layers, e.g. Radio Link Control (RLC), will discard the PDCP PDUs (RLC SDU) if these RLC SDU or any segment of the RLC SDU has not yet been transmitted to lower layers.

[0059] As discussed above, an application PDU, e.g. a video frame, is divided into multiple IP packets. All these IP packets which belong to one video frame can be defined as PDU Set.

[0060] Some embodiments herein accommodate for PDU sets being assigned with a PDU Set Importance (PSI) indicator, e.g., according to 3GPP TS 23.700-60 V18.0.0. This parameter can be used to identify the importance of a PDU Set within a quality of service (QoS) flow. Some embodiments enable use of the PSI for PDU Set level packet discarding, e.g., in presence of congestion.

[0061] In some embodiments, a PDU Set is as defined by TS 23.700-60 V18.0.0: PDU Set: A PDU Set is composed of one or more PDUs carrying the payload of one unit of information generated at the application level (e.g. a frame or video slice for XRM Services, as used in TR 26.926). In some implementations all PDUs in a PDU Set are needed by the application layer to use the corresponding unit of information. In other implementations, the application layer can still recover parts all or of the information unit, when some PDUs are missing.

[0062] Some embodiments concern a PDCP Sequence Number (SN) Gap report as described below. Using this report, the PDCP transmitter can inform the PDCP receiver of missing PDCP SN numbers, i.e. the PDCP SDUs that have been discarded and thus will not be transmitted. The information about missing SN will enable the receiver side to move the receiving window forward faster (reduce the waiting time of reordering timers) and allow for faster delivery of received packets to higher layers. Upon receiving the PDCP SN gap report, the receiver state variables (RX_NEXT, RX_DELIV and RX_REORD) are updated.

[0063] Some embodiments herein address the following challenge(s). With the PDU Set and PSI discarding feature there can be scenarios where the discard timer of low importance PDU Sets is shorter than the high importance PDU Sets. The low importance PDU Sets may have arrived later to the UE buffer than the high importance PDU Sets but may still expire the discard timer earlier. The PDU Sets may also be interleaved in the UE buffer. This creates a scenario that a PDCP SN Gap report is triggered for the discard of the SDUs belonging to the low importance PDU Set while there are still SDUs to be transmitted with lower SN belonging to a higher importance PDU Set.

[0064] The reception of such PDCP SN Gap report can in these cases create problems for the receiver by unnecessarily moving the receiving window forward (RX_NEXT). In some cases, this can make the later transmitted SDUs with lower SN to be ignored / discarded by the receiver, thereby not only preventing the packets to not be submitted to upper layers but also rendering the packets already stored in the receive buffer outdated due to reordering timer delays. This is due to the fact that XR traffic has short packet delay budgets. In addition, it could also lead to a loss of synchronization between the Tx and Rx windows.

[0065] Figure 6 illustrates an example of problems with a PDCP SN Gap report in these contexts. In this example, the conditions for triggering the PDCP SN gap report is when a lower SN is discarded when there is a higher SN present in the transmit buffer and the lower SN has not been transmitted by the lower layers yet. This example indicates a single SN here, but this also applies to multiple SNs.

[0066] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. Some embodiments make it conditional / configurable when the PDCP SN Gap report is triggered or adjust the content of the report, e.g. based on the features enabled or what discard timers that are running in the transmitter.

[0067] Certain embodiments may provide one or more of the following technical advantage(s). Some embodiments avoid sending problematic information in the PDCP SN Gap report when utilizing PSI discarding.

[0068] Consider two embodiments for how to change the usage of PDCP SN Gap report when used together with PSI discarding:

[0069] 1. Triggering of report

[0070] 2. Content of report

[0071] Either one or a combination of both is used. If multiple solutions are allowed, it may be up to the network to configure which one is utilized.

[0072] For the triggering of the report there are multiple options possible. One option is that if it is dependent on the PDU Set characteristic, e.g., if the SDU that is discarded belongs to a PDU Set of low importance, then a PDCP SN Gap report is not triggered. It can also be conditional on the relationship between PDU Sets in the buffer, e.g., if there is only one PDU Set or only one type of PDU Set in the buffer then the report is triggered but not if there are PDU Sets of different characteristics.

[0073] Figure 7 shows an example with respect to the characteristic of the PDU set. Here, the PDU sets can be classified into two types, e.g., high importance and low importance indicated by PSI (PDU set importance) in the 3GPP specification. These embodiments decide whether or not to trigger the PDCP SN gap report based on whether the discarding happens for low importance PDU sets or high importance PDU sets. If for low importance, then the gap report is not triggered as shown.

[0074] Another option is that it depends on the relationship between the characteristics of the PDU Sets and the number of PDU Sets in the buffer. For the number of PDU sets, in some embodiments, if more than a threshold number of PDU sets are discarded independent of low importance or high importance, then the PDCP gap report is triggered. Or this threshold number of PDU sets could only apply to the low importance PDU sets i.e., if low importance PDU sets are discarded, then only after a threshold number of packets discarded will the PDCP SN gap report be triggered.

[0075] Rules can also be based on the running discard timers, e.g., if multiple different timers are running simultaneously then depending on the remaining time to discard the remaining non-discarded SDUs can impact if a PDCP SN gap report is triggered or not.

[0076] More particularly, if there are different timers running (as is the case when PSI is configured) the timers may be timing out very close to each other. Then some embodiments avoid triggering a GAP report for the first discard, or rather delay the triggering of the first report, if a second report anyway will be triggered shortly or immediately after. This may be configured, e.g., it may also depend on how much data is going to be expired for the other discard timer, i.e. the time is very short and the remaining data is large then the timer will expire and discard happening.

[0077] An example:

[0078] LowImportanceDiscardTimer = 15ms DiscardTimer= 30ms

[0079] PDU Set 1 arrives at 0ms

[0080] PDU Set 2 arrives at 14ms

[0081] Discard of PDU Set 2 happens at 29ms Discard of PDU Set 1 happens at 30ms

[0082] PDCP Gap report can be delayed to be triggered at 30ms

[0083] In the same way as for the triggering of the report, the content of the PDPC SN Gap report can be adjusted based on the situation in the transmit buffer, e.g., on the PDU Set characteristics. Which SNs are included in the report can be limited based on the remaining non discarded SNs, e.g., not indicate SNs below or above the remaining non-discarded SNs depending on the scenario. The exact rules can be configured. This can also be impacted by the relationship between the characteristics of the PDU Sets, i.e., if they are of different importance levels and have different discard timer values. For example, the PDCP SN gap report can be limited to carry only information of X number of discarded SDUs, and the value of X can be configurable. This would prevent the RX_NEXT state variable at the receiver to advance to much higher values.

[0084] Continuing the example above, if a large number of low importance PDUs are discarded, the Tx entity can choose to split the report into two where the first indicates discarding of 3, 5, 7 and the second indicates the discarding of 9, 11. Thereby, the state variables at the receiver can be adjusted accordingly as shown in Figure 8.

[0085] Here, the gap report can be configured to only indicate SNs up to 7 or depending on the #PDUs discarded, can split the number. Here, in this example, there are 5 PDlls discarded, where 3 are sent in the first gap report and 2 in the second gap report. This can be indicated using the SNs of the non-discarded PDlls for e.g., in the first gap report, include SNs less than SN8 and in the second less than SN 12.

[0086] In the above case 3, 5, 6, 9, 11 are discarded and as explained depending on the #PDUs, the SNs above SN8 is not included in the gap report. In essence, depending on the #discarded SDlls, the report can be formulated in different ways:

[0087] Not include discarded SNs above a certain non-discarded SNs.

[0088] - #SNs to be included in the gap report (configured).

[0089] Dynamic splitting based on the #PDUs discarded for e.g., if 5 PDlls are discarded, split as 3 and 2. Or 2, 2 and 1.

[0090] In view of the modifications and variations herein, Figure 9 depicts a method performed by a communication node 12 for use in a communication network 10 in accordance with particular embodiments. The method includes storing multiple Packet Data Convergence Protocol, PDCP, packets 24 in a transmit buffer 26 of the communication node 12 (Block 900), and discarding a PDCP packet 24 from the transmit buffer 26 (Block 910). The method also comprises making a decision about whether or not the discarding of the PDCP packet 24 is to trigger transmission of a PDCP SN gap report 40 that reports one or more gaps in SNs of PDCP packets 24 from the communication node 12, wherein the decision is made based on one or more triggering criterions (Block 920). In some embodiments, the one or more triggering criterions include at least one or more characteristics of a PDU Set 22 to which the discarded PDCP packet 24 belongs and / or one or more characteristics of a PDU Set 22 to which another PDCP packet 24 stored in the transmit buffer 26 belongs. In other embodiments, the one or more triggering criterions include at least a number of PDU Sets 22, and / or a number of types of PDU Sets 22, to which the multiple PDCP packets 24 belong. In yet other embodiments, the one or more triggering criterions include at least a number of PDU Sets 22, and / or a number of types of PDU Sets 22, to which one or more PDCP packets 24 remaining in the transmit buffer 26 after discarding the PDCP packet 24 belong. In still yet other embodiments, the one or more triggering criterions include at least a value of a discard timer for another PDCP packet 24 stored in the transmit buffer 26. The method also comprises triggering or not triggering transmission of the PDCP SN gap report 40 according to the decision (Block 930). In some embodiments, the multiple PDCP packets 24 include at least a lower-SN PDCP packet 24 and a higher-SN PDCP packet 24, with a sequence number, SN, of the lower-SN PDCP packet 24 being lower than an SN of the higher-SN PDCP packet 24. In some embodiments, the discarded PDCP packet 24 is the higher-SN PDCP packet 24. In some embodiments, said discarding comprises discarding the higher-SN PDCP packet 24 from the transmit buffer 26 when the lower-SN PDCP packet 24 is still stored in the transmit buffer 26.

[0091] In some embodiments, the decision is made based on the one or more characteristics of the PDU Set 22 to which the discarded PDCP packet 24 belongs and / or the one or more characteristics of the PDU Set 22 to which another PDCP packet 24 stored in the transmit buffer 26 belongs. In some embodiments, the one or more characteristics include an importance level. In some embodiments, the decision is made that the discarding of the PDCP packet 24 is not to trigger transmission of the PDCP SN gap report 40, based at least in part on the importance level of the PDU Set 22 to which the PDCP packet 24 belongs being at or lower than a threshold level. In some embodiments, the multiple PDCP packets 24 include at least a lower-SN PDCP packet 24 and a higher-SN PDCP packet 24, with a sequence number, SN, of the lower-SN PDCP packet 24 being lower than an SN of the higher-SN PDCP packet 24. In some embodiments, the discarded PDCP packet 24 is the higher-SN PDCP packet 24. In some embodiments, said discarding comprises discarding the higher-SN PDCP packet 24 from the transmit buffer 26 when the lower-SN PDCP packet 24 is still stored in the transmit buffer 26. In some embodiments, the decision is made based on the one or more characteristics of the PDU Set 22 to which the higher-SN PDCP packet 24 belongs and the one or more characteristics of the PDU Set 22 to which the lower-SN PDCP packet 24 belongs. In some embodiments, the decision is made that the discarding of the PDCP packet 24 is not to trigger transmission of the PDCP SN gap report 40, based at least in part on the importance level of the PDU Set 22 to which the higher-SN PDCP packet 24 belongs being different than the importance level of the PDU Set 22 to which the lower-SN PDCP packet 24 belongs. In some embodiments, the decision is made that the discarding of the PDCP packet 24 is not to trigger transmission of the PDCP SN gap report 40, based at least in part on the importance level of the PDU Set 22 to which the higher-SN PDCP packet 24 belongs being less than the importance level of the PDU Set 22 to which the lower-SN PDCP packet 24 belongs.

[0092] In some embodiments, the one or more characteristics of a PDU Set 22 include a size of the PDU Set 22. In other embodiments, the one or more characteristics of a PDU Set 22 alternatively or additionally include a type of traffic conveyed by PDCP packets 24 that belong to the PDU Set 22. In some embodiments, the decision is made based on the number of PDU Sets 22, and / or the number of types of PDU Sets 22, to which the multiple PDCP packets 24 belong. In some embodiments, the decision is made to trigger transmission of the PDCP SN gap report 40 if the number of types of PDU Sets 22 to which the multiple PDCP packets 24 belong is equal to 1. In some embodiments, based on the number of types of PDU Sets 22 to which the multiple PDCP packets 24 belong being greater than 1 , the decision is made that the discarding of the PDCP packet 24 is not to trigger transmission of the PDCP SN gap report 40.

[0093] In some embodiments, different types of PDU Sets 22 have different importance levels.

[0094] In some embodiments, the decision is made based on the value of the discard timer for another PDCP packet 24 stored in the transmit buffer 26. In some embodiments, the decision is made that the discarding of the PDCP packet 24 is to trigger transmission of the PDCP SN gap report 40, based on the value of the discard timer for each other PDCP packet 24 stored in the transmit buffer 26 being greater than a threshold. In other embodiments, the decision is made that the discarding of the PDCP packet 24 not is to trigger transmission of the PDCP SN gap report 40, based on the value of the discard timer for each other PDCP packet 24 stored in the transmit buffer 26 being less than the threshold. In some embodiments, the threshold represents a maximum period of time for which transmission of the PDCP SN gap report 40 is able to be postponed in order for the PDCP SN gap report 40 to reflect discarding of one or more other PDCP packets 24 after discarding of the PDCP packet 24.

[0095] In some embodiments, said discarding is performed based on detecting expiration of a discard timer for the PDCP packet 24.

[0096] In some embodiments, said discarding is performed based on detecting expiration of a discard timer for another PDCP packet 24 that belongs to the same PDU Set 22 as the PDCP packet 24. In some embodiments, said discarding comprises discarding all PDCP packets 24 in the PDU Set 22 to which the PDCP packet 24 belongs.

[0097] In some embodiments, the PDCP packets 24 are PDCP service data units, SDUs.

[0098] In some embodiments, a PDU Set 22 includes PDCP packets 24 carrying the payload of one unit of information generated at an application layer.

[0099] In some embodiments, the method further comprises transmitting the PDCP SN gap report 40 responsive to triggering transmission of the PDCP SN gap report 40 (Block 980).

[0100] In some embodiments, the method is performed by a transmitting PDCP entity of the communication node 12.

[0101] In some embodiments, the communication node 12 is a communication device.

[0102] In some embodiments, the communication node 12 is a radio network node. In some embodiments, the method further comprises receiving signaling that indicates the threshold.

[0103] In some embodiments, the one or more characteristics of a PDU Set 22 include an importance level of the PDU Set 22 as indicated by a PDU Set Importance (PSI) indicator.

[0104] In some embodiments, the method further comprises receiving the PDCP packet 24 from a higher layer that is higher than a PDCP layer in a protocol stack at the communication node 12, and upon receiving the PDCP packet 24 from the higher layer, starting the discard timer for the PDCP packet 24. In some embodiments, the method further comprises transmitting the PDCP packet 24, storing the PDCP packet 24 in the transmit buffer 26 at the communication node 12, while the discard timer for the PDCP packet 24 is running, monitoring for reception of a PDCP status report indicating successful delivery of the PDCP packet 24, wherein the communication node 12 is configured to stop the discard timer for the PDCP packet 24 upon receiving a PDCP status report indicating successful delivery of the PDCP packet 24, and detecting expiration of the discard timer for the PDCP packet 24 before reception of any PDCP status report indicating successful delivery of the PDCP packet 24. In some embodiments, discarding the PDCP packet 24 comprises discarding the first PDCP packet 24 from the transmit buffer 26. In some embodiments, the multiple PDCP packets 24 include at least a lower-SN PDCP packet 24 and a higher-SN PDCP packet 24, with a sequence number, SN, of the lower-SN PDCP packet 24 being lower than an SN of the higher-SN PDCP packet 24. In some embodiments, the discarded PDCP packet 24 is the higher-SN PDCP packet 24. In some embodiments, the method further comprises receiving the higher-SN PDCP packet 24 from the higher layer after receiving the lower-SN PDCP packet 24 from the higher layer, and starting a discard timer for the lower-SN PDCP packet 24 before having started the discard timer for the higher-SN PDCP packet 24. In some embodiments, the discard timer for the higher-SN PDCP packet 24 is started with a value that is smaller than a value with which the discard timer for the lower-SN PDCP packet 24 is started. In some embodiments, expiration of the discard timer for the higher-SN PDCP packet 24 is detected also before expiration of the discard timer for the lower-SN PDCP packet 24 and before reception of any PDCP status report indicating successful delivery of the lower-SN PDCP packet 24, such that expiration of the discard timer for the higher-SN PDCP packet 24 is detected while the discard timer for the lower-SN PDCP packet 24 is still running.

[0105] In some embodiments, the multiple PDCP packets 24 belong to multiple PDU Sets 22. In some embodiments, at least some PDCP packets 24 that belong to different PDU Sets 22 are interleaved in the transmit buffer 26.

[0106] Figure 10 depicts a method performed by a communication node 12 for use in a communication network 10 in accordance with other particular embodiments. The method includes discarding one or more Packet Data Convergence Protocol, PDCP, packets 24 from a transmit buffer 26 within which is stored multiple PDCP packets 24 (Block 1000), and based on said discarding, generating a PDCP sequence number, SN, gap report 40 that reports one or more gaps in SNs of PDCP packets 24 from the communication node 12, wherein said generating comprises determining a content of the PDCP SN gap report 40 based on one or more content determination criterions (Block 1010). In some embodiments, the one or more content determination criterions include at least, for each of one or more of the one or more discarded PDCP packets 24, one or more characteristics of a PDU Set 22 to which the discarded PDCP packet 24 belongs. In some embodiments, the one or more content determination criterions include at least, for each of one or more non-discarded PDCP packets 24 that are not discarded from the transmit buffer 26, one or more characteristics of a PDU Set 22 to which the non-discarded PDCP packet 24 belongs. In some embodiments, the one or more content determination criterions include at least, for each of one or more non-discarded PDCP packets 24 that are not discarded from the transmit buffer 26, a value of a discard timer for the non-discarded PDCP packet 24. In some embodiments, the one or more content determination criterions include at least a number of PDU Sets 22, and / or a number of types of PDU Sets 22, to which the multiple PDCP packets 24 belong. In some embodiments, the one or more content determination criterions include at least a number of PDU Sets 22, and / or a number of types of PDU Sets 22, to which one or more non-discarded PDCP packets 24 that are not discarded from the transmit buffer 26 belong. The method also comprises transmitting the generated PDCP SN gap report 40 (Block 1020).

[0107] In some embodiments, multiple PDCP packets 24 are discarded from the transmit buffer 26, and wherein determining the content of the PDCP SN gap report 40 comprises determining, based on the one or more content determination criterions, for which of the multiple discarded PDCP packets 24 the PDCP SN gap report 40 is to report gaps. In some embodiments, said determining comprises determining, based on the one or more content determination criterions, a proper subset of the multiple discarded PDCP packets 24 for which the PDCP SN gap report 40 is to report gaps. In some embodiments, the PDCP SN gap report 40 is generated after discarding of all of the multiple PDCP packets 24, but reports gaps corresponding to less than all of the multiple PDCP packets 24 discarded.

[0108] In some embodiments, said determining is performed as part of determining the content of each of two or more PDCP SN gap reports 40 across which reporting of gaps corresponding to the multiple PDCP packets 24 discarded is split. In some embodiments, the two or more PDCP SN gap reports 40 include first and second PDCP SN gap reports 40, where the first PDCP SN gap report 40 reports gaps corresponding to a first proper subset of the multiple PDCP packets 24 discarded with SNs below a threshold SN, and the second PDCP SN gap report 40 reports gaps corresponding to a second proper subset of the multiple PDCP packets 24 with SNs above the threshold SN. In some embodiments, said determining comprises determining the threshold SN based on the one or more content determination criterions. In some embodiments, the threshold SN is an SN of a nondiscarded PDCP packet 24 in the transmit buffer 26. In some embodiments, the first and second subsets each include PDCP packets 24 that belong to a PDU Set 22 with an importance level lower than a threshold level, and wherein the non-discarded PDCP packet 24 with the threshold SN belongs to a PDU Set 22 with an importance level that equals or is above the threshold level. In some embodiments, the first and second subsets each include PDCP packets 24 that belong to the same PDU Set 22.

[0109] In some embodiments, said determining comprises, determining based on the one or more content determination criterions, whether or that reporting of gaps corresponding to the multiple PDCP packets 24 discarded is to be split across two or more PDCP SN gap reports 40. In some embodiments, the one or more content determination criterions include, for each of one or more of the one or more discarded PDCP packets 24, an importance level of a PDU Set 22 to which the discarded PDCP packet 24 belongs, and wherein said determining comprises determining, based on how many discarded packets 24 belong to a PDU Set 22 with an importance level lower than a threshold level, whether or that reporting of gaps corresponding to the multiple PDCP packets 24 discarded is to be split across two or more PDCP SN gap reports 40. In some embodiments, said determining comprises determining that reporting of gaps corresponding to the multiple PDCP packets 24 discarded is to be split across two or more PDCP SN gap reports 40, if at least a threshold number of discarded packets 24 belong to a PDU Set 22 with an importance level lower than a threshold level.

[0110] In some embodiments, the method further comprises receiving signaling indicating a maximum number of discarded PDCP packets 24 for which a PDCP SN gap report 40 is to report gaps.

[0111] In some embodiments, the one or more content determination criterions further include a number of the one or more PDCP packets 24 discarded from the transmit buffer 26.

[0112] In some embodiments, the method further comprises storing the multiple PDCP packets 24 in the transmit buffer 26 of the communication node 12.

[0113] In some embodiments, at least one of the one or more discarded PDCP packets 24 has an SN higher than at least one non-discarded PDCP packet 24 that is not discarded from the transmit buffer 26.

[0114] In some embodiments, the one or more content determination criterions include one or more of: for each of one or more of the one or more discarded PDCP packets 24, one or more characteristics of a PDU Set 22 to which the discarded PDCP packet 24 belongs; and / or for each of one or more non-discarded PDCP packets 24 that are not discarded from the transmit buffer 26, one or more characteristics of a PDU Set 22 to which the nondiscarded PDCP packet 24 belongs. In some embodiments, the one or more characteristics of a PDU Set 22 include an importance level of the PDU Set 22. In some embodiments, said determining comprises determining, based on at least a threshold number of discarded PDCP packets 24 belonging to a PDU Set 22 with an importance level lower than a threshold level, the content of the PDCP SN gap report 40 to include SNs of a proper subset of the discarded PDCP packets 24 so as to report gaps corresponding to the proper subset of the discarded PDCP packets 24. In some embodiments, the proper subset of the discarded PDCP packets 24 includes PDCP packets 24 with SNs up to a threshold SN corresponding to a selected non-discarded PDCP packet not discarded from the transmit buffer 26. In some embodiments, the selected non-discarded PDCP packet 24 belongs to a PDU Set 22 with an importance level equal to or above the threshold level.

[0115] In some embodiments, the one or more characteristics of a PDU Set 22 include: a size of the PDU Set 22; and / or a type of traffic conveyed by PDCP packets 24 that belong to the PDU Set 22.

[0116] In some embodiments, different types of PDU Sets 22 have different importance levels.

[0117] In some embodiments, the PDCP packets 24 are PDCP service data units, SDUs.

[0118] In some embodiments, a PDU Set 22 includes PDCP packets 24 carrying the payload of one unit of information generated at an application layer.

[0119] In some embodiments, the method is performed by a transmitting PDCP entity of the communication node 12.

[0120] In some embodiments, the communication node 12 is a communication device. In some embodiments, the communication node 12 is a radio network node. In some embodiments, the one or more characteristics of a PDU Set 22 include an importance level of the PDU Set 22 as indicated by a PDU Set Importance (PSI) indicator. In some embodiments, the method further comprises: receiving the multiple PDCP packets 24 from a higher layer that is higher than a PDCP layer in a protocol stack at the communication node 12; and upon receiving each PDCP packet 24 from the higher layer, starting a discard timer for the PDCP packet 24.

[0121] In some embodiments, each of the multiple PDCP packets 24 is discarded based on: expiration of a discard timer for the PDCP packet 24; or expiration of a discard timer for another PDCP packet 24 that belongs to the same PDU Set 22 as the PDCP packet 24, wherein all PDCP packets 24 in the PDU Set 22 to which the PDCP packet 24 belongs are discarded. Embodiments herein also include corresponding apparatuses. Embodiments herein for instance include a communication node 12 configured to perform any of the steps of any of the embodiments described above for the communication node 12.

[0122] Embodiments also include a communication node 12 comprising processing circuitry and power supply circuitry. The processing circuitry is configured to perform any of the steps of any of the embodiments described above for the communication node 12. The power supply circuitry is configured to supply power to the communication node 12.

[0123] Embodiments further include a communication node 12 comprising processing circuitry. The processing circuitry is configured to perform any of the steps of any of the embodiments described above for the communication node 12. In some embodiments, the communication node 12 further comprises communication circuitry.

[0124] Embodiments further include a communication node 12 comprising processing circuitry and memory. The memory contains instructions executable by the processing circuitry whereby the communication node 12 is configured to perform any of the steps of any of the embodiments described above for the communication node 12.

[0125] Embodiments moreover include a user equipment (UE). The UE comprises an antenna configured to send and receive wireless signals. The UE also comprises radio frontend circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry. The processing circuitry is configured to perform any of the steps of any of the embodiments described above for the communication node 12. In some embodiments, the UE also comprises an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry. The UE may comprise an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry. The UE may also comprise a battery connected to the processing circuitry and configured to supply power to the UE.

[0126] Embodiments herein also include a network node configured to perform any of the steps of any of the embodiments described above for the network node.

[0127] Embodiments also include a network node comprising processing circuitry and power supply circuitry. The processing circuitry is configured to perform any of the steps of any of the embodiments described above for the network node. The power supply circuitry is configured to supply power to the network node.

[0128] Embodiments further include a network node comprising processing circuitry. The processing circuitry is configured to perform any of the steps of any of the embodiments described above for the network node. In some embodiments, the network node further comprises communication circuitry. Embodiments further include a network node comprising processing circuitry and memory. The memory contains instructions executable by the processing circuitry whereby the network node is configured to perform any of the steps of any of the embodiments described above for the network node.

[0129] More particularly, the apparatuses described above may perform the methods herein and any other processing by implementing any functional means, modules, units, or circuitry. In one embodiment, for example, the apparatuses comprise respective circuits or circuitry configured to perform the steps shown in the method figures. The circuits or circuitry in this regard may comprise circuits dedicated to performing certain functional processing and / or one or more microprocessors in conjunction with memory. For instance, the circuitry may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (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, cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory may include program instructions for executing one or more telecommunications and / or data communications protocols as well as instructions for carrying out one or more of the techniques described herein, in several embodiments. In embodiments that employ memory, the memory stores program code that, when executed by the one or more processors, carries out the techniques described herein.

[0130] Figure 11 for example illustrates a communication node 12 as implemented in accordance with one or more embodiments. As shown, the communication node 12 includes processing circuitry 1110 and communication circuitry 1120. The communication circuitry 1120 (e.g., radio circuitry) is configured to transmit and / or receive information to and / or from one or more other nodes, e.g., via any communication technology. Such communication may occur via one or more antennas that are either internal or external to the communication device 1100. The processing circuitry 1110 is configured to perform processing described above, e.g., in Figure 9 and / or Figure 10, such as by executing instructions stored in memory 1130. The processing circuitry 1110 in this regard may implement certain functional means, units, or modules.

[0131] Figure 12 illustrates a network node 1200 as implemented in accordance with one or more embodiments. As shown, the network node 1200 includes processing circuitry 1210 and communication circuitry 1220. The communication circuitry 1220 is configured to transmit and / or receive information to and / or from one or more other nodes, e.g., via any communication technology. The processing circuitry 1210 is configured to perform processing described above, e.g., in Group B Embodiments, such as by executing instructions stored in memory 1230. The processing circuitry 1210 in this regard may implement certain functional means, units, or modules.

[0132] Those skilled in the art will also appreciate that embodiments herein further include corresponding computer programs.

[0133] A computer program comprises instructions which, when executed on at least one processor of an apparatus, cause the apparatus to carry out any of the respective processing described above. A computer program in this regard may comprise one or more code modules corresponding to the means or units described above.

[0134] Embodiments further include a carrier containing such a computer program. This carrier may comprise one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

[0135] In this regard, embodiments herein also include a computer program product stored on a non-transitory computer readable (storage or recording) medium and comprising instructions that, when executed by a processor of an apparatus, cause the apparatus to perform as described above.

[0136] Embodiments further include a computer program product comprising program code portions for performing the steps of any of the embodiments herein when the computer program product is executed by a computing device. This computer program product may be stored on a computer readable recording medium.

[0137] Figure 13 shows an example of a communication system 1300 in accordance with some embodiments.

[0138] In the example, the communication system 1300 includes a telecommunication network 1302 that includes an access network 1304, such as a radio access network (RAN), and a core network 1306, which includes one or more core network nodes 1308. The access network 1304 includes one or more access network nodes, such as network nodes 1310a and 1310b (one or more of which may be generally referred to as network nodes 1310), or any other similar 3rdGeneration Partnership Project (3GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network 1302 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 1302 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 1302, including one or more network nodes 1310 and / or core network nodes 1308. Examples of an ORAN network node include an open radio unit (0-Rll), an open distributed unit (0-Dll), an open central unit (O-CU), including an O-CU control plane (O- CLI-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an A1, F1, W1, E1 , E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an 0-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes 1310 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 1312a, 1312b, 1312c, and 1312d (one or more of which may be generally referred to as UEs 1312) to the core network 1306 over one or more wireless connections.

[0139] 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, the communication system 1300 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. The communication system 1300 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0140] The UEs 1312 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 1310 and other communication devices. Similarly, the network nodes 1310 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 1312 and / or with other network nodes or equipment in the telecommunication network 1302 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 1302.

[0141] In the depicted example, the core network 1306 connects the network nodes 1310 to one or more host computing systems, such as host 1316. 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. The core network 1306 includes one more core network nodes (e.g., core network node 1308) 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 1308. 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 (ALISF), 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).

[0142] The host 1316 may be under the ownership or control of a service provider other than an operator or provider of the access network 1304 and / or the telecommunication network 1302. The host 1316 may host a variety 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.

[0143] As a whole, the communication system 1300 of Figure 13 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.

[0144] In some examples, the telecommunication network 1302 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 1302 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 1302. For example, the telecommunications network 1302 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.

[0145] In some examples, the UEs 1312 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 1304 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 1304. 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).

[0146] In the example, the hub 1314 communicates with the access network 1304 to facilitate indirect communication between one or more UEs (e.g., UE 1312c and / or 1312d) and network nodes (e.g., network node 1310b). In some examples, the hub 1314 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 1314 may be a broadband router enabling access to the core network 1306 for the UEs. As another example, the hub 1314 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 1310, or by executable code, script, process, or other instructions in the hub 1314. As another example, the hub 1314 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, the hub 1314 may be a content source. For example, for a UE that is a VR device, display, loudspeaker, or other media delivery device, the hub 1314 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 1314 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 1314 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0147] The hub 1314 may have a constant / persistent or intermittent connection to the network node 1310b. The hub 1314 may also allow for a different communication scheme and / or schedule between the hub 1314 and UEs (e.g., UE 1312c and / or 1312d), and between the hub 1314 and the core network 1306. In other examples, the hub 1314 is connected to the core network 1306 and / or one or more UEs via a wired connection. Moreover, the hub 1314 may be configured to connect to an M2M service provider over the access network 1304 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 1310 while still connected via the hub 1314 via a wired or wireless connection. In some embodiments, the hub 1314 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 1310b. In other embodiments, the hub 1314 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 1310b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0148] Figure 14 shows a UE 1400 in accordance with some embodiments. The UE 1400 presents additional details of some embodiments of the UE 1312 of Figure 1. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. 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), wireless cameras, gaming console or device, music storage / playback device, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), an Augmented Reality (AR) or Virtual Reality (VR) device, wireless customer-premise equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB- loT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0149] 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).

[0150] The UE 1400 includes processing circuitry 1402 that is operatively coupled via a bus 1404 to an input / output interface 1406, a power source 1408, a memory 1410, a communication interface 1412, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 14. 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, receivers, etc. The processing circuitry 1402 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 the memory 1410. The processing circuitry 1402 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 1402 may include multiple central processing units (CPUs).

[0151] In the example, the input / output interface 1406 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 input device may allow a user to capture information into the UE 1400. 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.

[0152] In some embodiments, the power source 1408 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. The power source 1408 may further include power circuitry for delivering power from the power source 1408 itself, and / or an external power source, to the various parts of the UE 1400 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 1408. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 1408 to make the power suitable for the respective components of the UE 1400 to which power is supplied.

[0153] The memory 1410 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, the memory 1410 includes one or more application programs 1414, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1416. The memory 1410 may store, for use by the UE 1400, any of a variety of various operating systems or combinations of operating systems.

[0154] The memory 1410 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 (eUlCC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 1410 may allow the UE 1400 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 the memory 1410, which may be or comprise a device-readable storage medium.

[0155] The processing circuitry 1402 may be configured to communicate with an access network or other network using the communication interface 1412. The communication interface 1412 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1422. The communication interface 1412 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 a transmitter 1418 and / or a receiver 1420 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 1418 and receiver 1420 may be coupled to one or more antennas (e.g., antenna 1422) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0156] In the illustrated embodiment, communication functions of the communication interface 1412 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 / internet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0157] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1412, 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., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0158] 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 wireless connection. 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.

[0159] 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 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 1400 shown in Figure 14. 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-loT 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.

[0160] 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. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0161] Figure 15 shows a network node 1500 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU).

[0162] 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, distributed units (e.g., in an O- RAN access node) 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).

[0163] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, 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).

[0164] The network node 1500 includes a processing circuitry 1502, a memory 1504, a communication interface 1506, and a power source 1508. The network node 1500 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 the network node 1500 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, the network node 1500 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1504 for different RATs) and some components may be reused (e.g., a same antenna 1510 may be shared by different RATs). The network node 1500 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1500, 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 1500.

[0165] The processing circuitry 1502 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 1500 components, such as the memory 1504, to provide network node 1500 functionality.

[0166] In some embodiments, the processing circuitry 1502 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1502 includes one or more of radio frequency (RF) transceiver circuitry 1512 and baseband processing circuitry 1514. In some embodiments, the radio frequency (RF) transceiver circuitry 1512 and the baseband processing circuitry 1514 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 1512 and baseband processing circuitry 1514 may be on the same chip or set of chips, boards, or units. The memory 1504 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 the processing circuitry 1502. The memory 1504 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 capable of being executed by the processing circuitry 1502 and utilized by the network node 1500. The memory 1504 may be used to store any calculations made by the processing circuitry 1502 and / or any data received via the communication interface 1506. In some embodiments, the processing circuitry 1502 and memory 1504 is integrated.

[0167] The communication interface 1506 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 1506 comprises port(s) / terminal(s) 1516 to send and receive data, for example to and from a network over a wired connection. The communication interface 1506 also includes radio front-end circuitry 1518 that may be coupled to, or in certain embodiments a part of, the antenna 1510. Radio front-end circuitry 1518 comprises filters 1520 and amplifiers 1522. The radio front-end circuitry 1518 may be connected to an antenna 1510 and processing circuitry 1502. The radio front-end circuitry may be configured to condition signals communicated between antenna 1510 and processing circuitry 1502. The radio front-end circuitry 1518 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 1518 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1520 and / or amplifiers 1522. The radio signal may then be transmitted via the antenna 1510. Similarly, when receiving data, the antenna 1510 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1518. The digital data may be passed to the processing circuitry 1502. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0168] In certain alternative embodiments, the network node 1500 does not include separate radio front-end circuitry 1518, instead, the processing circuitry 1502 includes radio front-end circuitry and is connected to the antenna 1510. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1512 is part of the communication interface 1506. In still other embodiments, the communication interface 1506 includes one or more ports or terminals 1516, the radio front-end circuitry 1518, and the RF transceiver circuitry 1512, as part of a radio unit (not shown), and the communication interface 1506 communicates with the baseband processing circuitry 1514, which is part of a digital unit (not shown).

[0169] The antenna 1510 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1510 may be coupled to the radio front-end circuitry 1518 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1510 is separate from the network node 1500 and connectable to the network node 1500 through an interface or port.

[0170] The antenna 1510, communication interface 1506, and / or the processing circuitry 1502 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, the antenna 1510, the communication interface 1506, and / or the processing circuitry 1502 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.

[0171] The power source 1508 provides power to the various components of network node 1500 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1508 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1500 with power for performing the functionality described herein. For example, the network node 1500 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 the power source 1508. As a further example, the power source 1508 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.

[0172] Embodiments of the network node 1500 may include additional components beyond those shown in Figure 15 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, the network node 1500 may include user interface equipment to allow input of information into the network node 1500 and to allow output of information from the network node 1500. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1500. In some embodiments providing a core network node, such as core network node 108 of FIG. 13, some components, such as the radio front-end circuitry 1518 and the RF transceiver circuitry 1512 may be omitted.

[0173] Figure 16 is a block diagram illustrating a virtualization environment 1600 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 1600 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 embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 1600 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an O-2 interface. Virtualization may facilitate distributed implementations of a network node, UE, core network node, or host.

[0174] Applications 1602 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0175] Hardware 1604 includes processing circuitry, memory that stores software and / or instructions 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 1606 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1608a and 1608b (one or more of which may be generally referred to as VMs 1608), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1606 may present a virtual operating platform that appears like networking hardware to the VMs 1608.

[0176] The VMs 1608 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1606. Different embodiments of the instance of a virtual appliance 1602 may be implemented on one or more of VMs 1608, 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.

[0177] In the context of NFV, a VM 1608 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1608, and that part of hardware 1604 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 1608 on top of the hardware 1604 and corresponds to the application 1602.

[0178] Hardware 1604 may be implemented in a standalone network node with generic or specific components. Hardware 1604 may implement some functions via virtualization. Alternatively, hardware 1604 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 1610, which, among others, oversees lifecycle management of applications 1602. In some embodiments, hardware 1604 is coupled to one or more radio units that each include one or more transmitters and one or more receivers 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 1612 which may alternatively be used for communication between hardware nodes and radio units.

[0179] Although the computing devices described herein (e.g., UEs, network nodes) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0180] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer- readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

[0181] Some embodiments herein include those enumerated below.

[0182] Group A Embodiments

[0183] A1. A method performed by a communication node for use in a communication network, the method comprising: storing multiple Packet Data Convergence Protocol, PDCP, packets in a transmit buffer of the communication node; discarding a PDCP packet from the transmit buffer; making a decision about whether or not the discarding of the PDCP packet is to trigger transmission of a PDCP SN gap report that reports one or more gaps in SNs of PDCP packets from the communication node, wherein the decision is made based on one or more triggering criterions, wherein the one or more triggering criterions include one or more of: one or more characteristics of a PDU Set to which the discarded PDCP packet belongs and / or one or more characteristics of a PDU Set to which another PDCP packet stored in the transmit buffer belongs; a number of PDU Sets, and / or a number of types of PDU Sets, to which the multiple PDCP packets belong; a number of PDU Sets, and / or a number of types of PDU Sets, to which one or more PDCP packets remaining in the transmit buffer after discarding the PDCP packet belong; or a value of a discard timer for another PDCP packet stored in the transmit buffer; and triggering or not triggering transmission of the PDCP SN gap report according to the decision.

[0184] A2. The method of embodiment A1 , wherein the multiple PDCP packets include at least a lower-SN PDCP packet and a higher-SN PDCP packet, with a sequence number, SN, of the lower-SN PDCP packet being lower than an SN of the higher-SN PDCP packet, wherein the discarded PDCP packet is the higher-SN PDCP packet.

[0185] A3. The method of embodiment A2, wherein said discarding comprises discarding the higher-SN PDCP packet from the transmit buffer when the lower-SN PDCP packet is still stored in the transmit buffer.

[0186] A4. The method of any of embodiments A1-A3, wherein the one or more triggering criterions include the one or more characteristics of the PDU Set to which the discarded PDCP packet belongs and / or the one or more characteristics of the PDU Set to which another PDCP packet stored in the transmit buffer belongs.

[0187] A5. The method of embodiment A4, wherein the one or more characteristics include an importance level.

[0188] A6. The method of embodiment A5, wherein the decision is made that the discarding of the PDCP packet is not to trigger transmission of the PDCP SN gap report, based at least in part on the importance level of the PDU Set to which the PDCP packet belongs being at or lower than a threshold level.

[0189] A7. The method of embodiment A5, wherein the multiple PDCP packets include at least a lower-SN PDCP packet and a higher-SN PDCP packet, with a sequence number, SN, of the lower-SN PDCP packet being lower than an SN of the higher-SN PDCP packet, wherein the discarded PDCP packet is the higher-SN PDCP packet, wherein said discarding comprises discarding the higher-SN PDCP packet from the transmit buffer when the lower-SN PDCP packet is still stored in the transmit buffer, wherein the one or more triggering criterions include the one or more characteristics of the PDU Set to which the higher-SN PDCP packet belongs and the one or more characteristics of the PDU Set to which the lower-SN PDCP packet belongs. A8. The method of embodiment A7, wherein the decision is made that the discarding of the PDCP packet is not to trigger transmission of the PDCP SN gap report, based at least in part on the importance level of the PDU Set to which the higher-SN PDCP packet belongs being different than the importance level of the PDU Set to which the lower-SN PDCP packet belongs.

[0190] A9. The method of embodiment A7, wherein the decision is made that the discarding of the PDCP packet is not to trigger transmission of the PDCP SN gap report, based at least in part on the importance level of the PDU Set to which the higher-SN PDCP packet belongs being less than the importance level of the PDU Set to which the lower-SN PDCP packet belongs.

[0191] A10. The method of any of any of embodiments A1-A9, wherein the one or more characteristics of a PDU Set include: a size of the PDU Set; and / or a type of traffic conveyed by PDCP packets that belong to the PDU Set.

[0192] A11. The method of any of embodiments A1-A10, wherein the one or more triggering criterions include the number of PDU Sets, and / or the number of types of PDU Sets, to which the multiple PDCP packets belong.

[0193] A12. The method of embodiment A11 , wherein the decision is made to trigger transmission of the PDCP SN gap report if the number of types of PDU Sets to which the multiple PDCP packets belong is equal to 1.

[0194] A13. The method of any of embodiments A11-A12, wherein, based on the number of types of PDU Sets to which the multiple PDCP packets belong being greater than 1, the decision is made that the discarding of the PDCP packet is not to trigger transmission of the PDCP SN gap report.

[0195] A14. The method of any of embodiments A1-A13, wherein different types of PDU Sets have different importance levels.

[0196] A15. The method of any of embodiments A1-A14, wherein the one or more triggering criterions include the value of the discard timer for another PDCP packet stored in the transmit buffer.

[0197] A16. The method of embodiment A15, wherein the decision is made that: the discarding of the PDCP packet is to trigger transmission of the PDCP SN gap report, based on the value of the discard timer for each other PDCP packet stored in the transmit buffer being greater than a threshold; or the discarding of the PDCP packet not is to trigger transmission of the PDCP SN gap report, based on the value of the discard timer for each other PDCP packet stored in the transmit buffer being less than the threshold.

[0198] A17. The method of any of embodiments A15-A16, wherein the threshold represents a maximum period of time for which transmission of the PDCP SN gap report is able to be postponed in order for the PDCP SN gap report to reflect discarding of one or more other PDCP packets after discarding of the PDCP packet.

[0199] A18. The method of any of embodiments A1-A17, wherein said discarding is performed based on detecting expiration of a discard timer for the PDCP packet.

[0200] A19. The method of any of embodiments A1-A14, wherein said discarding is performed based on detecting expiration of a discard timer for another PDCP packet that belongs to the same PDU Set as the PDCP packet, wherein said discarding comprises discarding all PDCP packets in the PDU Set to which the PDCP packet belongs.

[0201] A20. The method of any of embodiments A1-A19, wherein the PDCP packets are PDCP service data units, SDUs.

[0202] A21. The method of any of embodiments A1-A20, wherein a PDU Set includes PDCP packets carrying the payload of one unit of information generated at an application layer.

[0203] A22. The method of any of embodiments A1-A21 , further comprising transmitting the PDCP SN gap report responsive to triggering transmission of the PDCP SN gap report.

[0204] A23. The method of any of embodiments A1-A22, wherein the method is performed by a transmitting PDCP entity of the communication node.

[0205] A24. The method of any of embodiments A1-A23, wherein the communication node is a communication device.

[0206] A25. The method of any of embodiments A1-A23, wherein the communication node is a radio network node. A26. The method of embodiment A16, further comprising receiving signaling that indicates the threshold.

[0207] A27. The method of any of embodiments A1-A5, wherein the one or more characteristics of a PDU Set include an importance level of the PDU Set as indicated by a PDU Set Importance (PSI) indicator.

[0208] A28. The method of embodiment A18, further comprising: receiving the PDCP packet from a higher layer that is higher than a PDCP layer in a protocol stack at the communication node; and upon receiving the PDCP packet from the higher layer, starting the discard timer for the PDCP packet.

[0209] A29. The method of embodiment A28, further comprising: transmitting the PDCP packet; storing the PDCP packet in the transmit buffer at the communication node; while the discard timer for the PDCP packet is running, monitoring for reception of a PDCP status report indicating successful delivery of the PDCP packet, wherein the communication node is configured to stop the discard timer for the PDCP packet upon receiving a PDCP status report indicating successful delivery of the PDCP packet; and detecting expiration of the discard timer for the PDCP packet before reception of any PDCP status report indicating successful delivery of the PDCP packet; wherein discarding the PDCP packet comprises discarding the first PDCP packet from the transmit buffer.

[0210] A30. The method of embodiment A29, wherein the multiple PDCP packets include at least a lower-SN PDCP packet and a higher-SN PDCP packet, with a sequence number, SN, of the lower-SN PDCP packet being lower than an SN of the higher-SN PDCP packet, wherein the discarded PDCP packet is the higher-SN PDCP packet, wherein the method further comprises receiving the higher-SN PDCP packet from the higher layer after receiving the lower-SN PDCP packet from the higher layer, and starting a discard timer for the lower-SN PDCP packet before having started the discard timer for the higher-SN PDCP packet, wherein the discard timer for the higher-SN PDCP packet is started with a value that is smaller than a value with which the discard timer for the lower-SN PDCP packet is started, wherein expiration of the discard timer for the higher-SN PDCP packet is detected also before expiration of the discard timer for the lower-SN PDCP packet and before reception of any PDCP status report indicating successful delivery of the lower-SN PDCP packet, such that expiration of the discard timer for the higher-SN PDCP packet is detected while the discard timer for the lower-SN PDCP packet is still running.

[0211] A31. The method of any of embodiments A1-A31 , wherein the multiple PDCP packets belong to multiple PDU Sets, wherein at least some PDCP packets that belong to different PDU Sets are interleaved in the transmit buffer.

[0212] AA1. A method performed by a communication node for use in a communication network, the method comprising: storing, in a transmit buffer of the communication node, multiple Packet Data Convergence Protocol, PDCP, packets, including at least a lower-SN PDCP packet and a higher-SN PDCP packet, with a sequence number, SN, of the lower-SN PDCP packet being lower than an SN of the higher-SN PDCP packet; discarding the higher-SN PDCP packet from the transmit buffer when the lower-SN PDCP packet is still stored in the transmit buffer; making a decision about whether or not the discarding of the higher-SN PDCP packet is to trigger transmission of a PDCP SN gap report that reports one or more gaps in SNs of PDCP packets from the communication node, wherein the decision is made based on one or more triggering criterions, wherein the one or more triggering criterions include one or more of: one or more characteristics of a PDU Set to which the higher-SN PDCP packet belongs and / or one or more characteristics of a PDU Set to which the lower-SN PDCP packet belongs; a number of PDU Sets, and / or a number of types of PDU Sets, to which the multiple PDCP packets belong; a number of PDU Sets, and / or a number of types of PDU Sets, to which one or more PDCP packets remaining in the transmit buffer after discarding the higher-SN PDCP packet belong; or a value of a discard timer for another PDCP packet stored in the transmit buffer; and triggering or not triggering transmission of the PDCP SN gap report according to the decision.

[0213] AAA1. A method performed by a communication node for use in a communication network, the method comprising: discarding one or more Packet Data Convergence Protocol, PDCP, packets from a transmit buffer within which is stored multiple PDCP packets; based on said discarding, generating a PDCP sequence number, SN, gap report that reports one or more gaps in SNs of PDCP packets from the communication node, wherein said generating comprises determining a content of the PDCP SN gap report based on one or more content determination criterions, wherein the one or more content determination criterions include one or more of: for each of one or more of the one or more discarded PDCP packets, one or more characteristics of a PDU Set to which the discarded PDCP packet belongs; for each of one or more non-discarded PDCP packets that are not discarded from the transmit buffer, one or more characteristics of a PDU Set to which the non-discarded PDCP packet belongs; for each of one or more non-discarded PDCP packets that are not discarded from the transmit buffer, a value of a discard timer for the nondiscarded PDCP packet; a number of PDU Sets, and / or a number of types of PDU Sets, to which the multiple PDCP packets belong; or a number of PDU Sets, and / or a number of types of PDU Sets, to which one or more non-discarded PDCP packets that are not discarded from the transmit buffer belong; and transmitting the generated PDCP SN gap report.

[0214] AAA2. The method of embodiment AAA1, wherein multiple PDCP packets are discarded from the transmit buffer, and wherein determining the content of the PDCP SN gap report comprises determining, based on the one or more content determination criterions, for which of the multiple discarded PDCP packets the PDCP SN gap report is to report gaps.

[0215] AAA3. The method of embodiment AAA2, wherein said determining comprises determining, based on the one or more content determination criterions, a proper subset of the multiple discarded PDCP packets for which the PDCP SN gap report is to report gaps.

[0216] AAA4. The method of embodiment AAA3, wherein the PDCP SN gap report is generated after discarding of all of the multiple PDCP packets, but reports gaps corresponding to less than all of the multiple PDCP packets discarded. AAA5. The method of any of embodiments AAA1-AAA4, wherein said determining is performed as part of determining the content of each of two or more PDCP SN gap reports across which reporting of gaps corresponding to the multiple PDCP packets discarded is split.

[0217] AAA6. The method of embodiment AAA5, wherein the two or more PDCP SN gap reports include first and second PDCP SN gap reports, wherein the first PDCP SN gap report reports gaps corresponding to a first proper subset of the multiple PDCP packets discarded with SNs below a threshold SN, and the second PDCP SN gap report reports gaps corresponding to a second proper subset of the multiple PDCP packets with SNs above the threshold SN.

[0218] AAA7. The method of embodiment AAA6, wherein said determining comprises determining the threshold SN based on the one or more content determination criterions.

[0219] AAA8. The method of any of embodiments AAA6-AAA7, wherein the threshold SN is an SN of a non-discarded PDCP packet in the transmit buffer.

[0220] AAA9. The method of embodiment AAA8, wherein the first and second subsets each include PDCP packets that belong to a PDU Set with an importance level lower than a threshold level, and wherein the non-discarded PDCP packet with the threshold SN belongs to a PDU Set with an importance level that equals or is above the threshold level.

[0221] AAA10. The method of any of embodiments AAA8-AAA9, wherein the first and second subsets each include PDCP packets that belong to the same PDU Set.

[0222] AAA11. The method of any of embodiments AAA1-AAA10, wherein said determining comprises, determining based on the one or more content determination criterions, whether or that reporting of gaps corresponding to the multiple PDCP packets discarded is to be split across two or more PDCP SN gap reports.

[0223] AAA12. The method of embodiment AAA11 , wherein the one or more content determination criterions include, for each of one or more of the one or more discarded PDCP packets, an importance level of a PDU Set to which the discarded PDCP packet belongs, and wherein said determining comprises determining, based on how many discarded packets belong to a PDU Set with an importance level lower than a threshold level, whether or that reporting of gaps corresponding to the multiple PDCP packets discarded is to be split across two or more PDCP SN gap reports.

[0224] AAA13. The method of embodiment AAA12, wherein said determining comprises determining that reporting of gaps corresponding to the multiple PDCP packets discarded is to be split across two or more PDCP SN gap reports, if at least a threshold number of discarded packets belong to a PDU Set with an importance level lower than a threshold level.

[0225] AAA14. The method of any of embodiments AAA1-AAA13, further comprising receiving signaling indicating a maximum number of discarded PDCP packets for which a PDCP SN gap report is to report gaps.

[0226] AAA15. The method of any of embodiments AAA1-AAA14, wherein the one or more content determination criterions further include a number of the one or more PDCP packets discarded from the transmit buffer.

[0227] AAA16. The method of any of embodiments AAA1-AAA15, further comprising storing the multiple PDCP packets in the transmit buffer of the communication node.

[0228] AAA17. The method of any of embodiments AAA1-AAA16, wherein at least one of the one or more discarded PDCP packets has an SN higher than at least one non-discarded PDCP packet that is not discarded from the transmit buffer.

[0229] AAA18. The method of any of embodiments AAA1-AAA17, wherein the one or more content determination criterions include one or more of: for each of one or more of the one or more discarded PDCP packets, one or more characteristics of a PDU Set to which the discarded PDCP packet belongs; and / or for each of one or more non-discarded PDCP packets that are not discarded from the transmit buffer, one or more characteristics of a PDU Set to which the nondiscarded PDCP packet belongs.

[0230] AAA19. The method of embodiment AAA18, wherein the one or more characteristics of a PDU Set include an importance level of the PDU Set.

[0231] AAA20. The method of embodiment AAA19, wherein said determining comprises determining, based on at least a threshold number of discarded PDCP packets belonging to a PDU Set with an importance level lower than a threshold level, the content of the PDCP SN gap report to include SNs of a proper subset of the discarded PDCP packets so as to report gaps corresponding to the proper subset of the discarded PDCP packets.

[0232] AAA21. The method of embodiment AAA20, wherein the proper subset of the discarded PDCP packets includes PDCP packets with SNs up to a threshold SN corresponding to a selected non-discarded PDCP packet not discarded from the transmit buffer.

[0233] AAA22. The method of embodiment AAA21, wherein the selected non-discarded PDCP packet belongs to a PDU Set with an importance level equal to or above the threshold level.

[0234] AAA23. The method of any of any of embodiments AAA1-AAA22, wherein the one or more characteristics of a PDU Set include: a size of the PDU Set; and / or a type of traffic conveyed by PDCP packets that belong to the PDU Set.

[0235] AAA24. The method of any of embodiments AAA1-AAA23, wherein different types of PDU Sets have different importance levels.

[0236] AAA25. The method of any of embodiments AAA1-AAA24, wherein the PDCP packets are PDCP service data units, SDUs.

[0237] AAA26. The method of any of embodiments AAA1-AAA25, wherein a PDU Set includes PDCP packets carrying the payload of one unit of information generated at an application layer.

[0238] AAA27. The method of any of embodiments AAA1-AAA26, wherein the method is performed by a transmitting PDCP entity of the communication node.

[0239] AAA28. The method of any of embodiments AAA1-AAA27, wherein the communication node is a communication device.

[0240] AAA29. The method of any of embodiments AAA1-AAA27, wherein the communication node is a radio network node. AAA30. The method of any of embodiments AAA1-AAA29, wherein the one or more characteristics of a PDU Set include an importance level of the PDU Set as indicated by a PDU Set Importance (PSI) indicator.

[0241] AAA31 . The method of embodiment AAA30, further comprising: receiving the multiple PDCP packets from a higher layer that is higher than a PDCP layer in a protocol stack at the communication node; and upon receiving each PDCP packet from the higher layer, starting a discard timer for the PDCP packet.

[0242] AAA32. The method of any of embodiments AAA1-AAA31 , wherein each of the multiple

[0243] PDCP packets is discarded based on: expiration of a discard timer for the PDCP packet; or expiration of a discard timer for another PDCP packet that belongs to the same PDU Set as the PDCP packet, wherein all PDCP packets in the PDU Set to which the PDCP packet belongs are discarded.

[0244] Group B Embodiments

[0245] B1 . A method performed by a network node, the method comprising: transmitting, to a communication node, signaling that configures the communication network to operate according to any of the Group A embodiments.

[0246] Group C Embodiments

[0247] C1 . A communication node configured to perform any of the steps of any of the Group A embodiments.

[0248] C2. A communication node comprising processing circuitry configured to any of the steps of any of the Group A embodiments.

[0249] C3. A communication node comprising: communication circuitry; and processing circuitry configured to perform any of the steps of any of the Group A embodiments.

[0250] 04. A communication node comprising: processing circuitry configured to perform any of the steps of any of the Group A embodiments; and power supply circuitry configured to supply power to the communication node.

[0251] C5. A communication node comprising: processing circuitry and memory, the memory containing instructions executable by the processing circuitry whereby the communication node is configured to perform any of the steps of any of the Group A embodiments.

[0252] 06. The communication node of any of embodiments 01 -05, wherein the communication node is a communication device.

[0253] 07. A user equipment (UE) comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

[0254] 08. A computer program comprising instructions which, when executed by at least one processor of a communication node, causes the communication node to perform any of the steps of any of the Group A embodiments.

[0255] 09. A carrier containing the computer program of embodiment 07, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

[0256] 010. A network node configured to perform any of the steps of any of the Group B embodiments.

[0257] 011. A network node comprising processing circuitry configured to perform any of the steps of any of the Group B embodiments.

[0258] C12. A network node comprising: communication circuitry; and processing circuitry configured to perform any of the steps of any of the Group B embodiments.

[0259] C13. A network node comprising: processing circuitry configured to perform any of the steps of any of the Group B embodiments; power supply circuitry configured to supply power to the network node.

[0260] C14. A network node comprising: processing circuitry and memory, the memory containing instructions executable by the processing circuitry whereby the network node is configured to perform any of the steps of any of the Group B embodiments.

[0261] C15. The network node of any of embodiments C10-C14, wherein the network node is a base station.

[0262] 016. A computer program comprising instructions which, when executed by at least one processor of a network node, causes the network node to perform any of the steps of any of the Group B embodiments.

[0263] 017. The computer program of embodiment 016, wherein the network node is a base station.

[0264] 018. A carrier containing the computer program of any of embodiments 016-017, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

[0265] ABBREVIATIONS

[0266] At least some of the following abbreviations may be used in this disclosure. If there is an inconsistency between abbreviations, preference should be given to how it is used above. If listed multiple times below, the first listing should be preferred over any subsequent listing(s). XR extended Reality eMBB Enhanced Mobile BroadBand VR Virtual Reality 5GC 5G Core NR New Radio UR LLC Ultra-Reliable Low Latency Communications MR Mixed Reality AR Augmented Reality TTI Time Transmission Interval RAN Radio Access Network TB Transport Block Fps Frames Per Second KB Kilobytes IP Internet Protocol VoIP Voice over IP PDU Protocol Data Unit PDCP Packet Data Convergence Protocol SDU Service Data Unit RLC Radio Link Controller PSI PDU Set Importnce 3GPP 3rd Generation Partnership Project DRB Dedicated Radio Bearer DL Downlink UL Uplink UE User Equipment RRC Radio Resource Controller L1 Layer 1 DCI Downlink Control Information PDCCH Physical Dedicated Control Channel 3GPP 3rd Generation Partnership Project 5G 5th Generation 6G 6thGeneration ABS Almost Blank Subframe ARQ Automatic Repeat Request AWGN Additive White Gaussian Noise BCCH Broadcast Control Channel BCH Broadcast Channel CA Carrier Aggregation CC Carrier Component

[0267] CCCH SDU Common Control Channel SDU CDMA Code Division Multiplex Access CGI Cell Global Identity CIR Channel Impulse Response CP Cyclic Prefix CPICH Common Pilot Channel CQI Channel Quality Information C-RNTI Cell RNTI CSI Channel State Information DCCH Dedicated Control Channel DL Downlink DM Demodulation DMRS Demodulation Reference Signal DRX Discontinuous Reception DTX Discontinuous Transmission DTCH Dedicated Traffic Channel DUT Device Under Test E-CID Enhanced Cell-1 D (positioning method) Ec / No Received energy per chip divided by the power density in the band eMBMS Evolved Multimedia Broadcast Multicast Services ECGI Evolved CGI eNB E-UTRAN NodeB ePDCCH Enhanced Physical Downlink Control Channel E-SMLC Evolved Serving Mobile Location Center E-UTRAN Evolved Universal Terrestrial Radio Access Network FDD Frequency Division Duplex FFS For Further Study gNB Base station in NR GNSS Global Navigation Satellite System HARQ Hybrid Automatic Repeat Request HO Handover HSPA High Speed Packet Access HRPD High Rate Packet Data LOS Line of Sight LPP LTE Positioning Protocol LTE Long-Term Evolution MAC Medium Access Control MAC Message Authentication Code MBSFN Multimedia Broadcast Multicast Service Single Frequency Network MBSFN ABS MBSFN Almost Blank Subframe MDT Minimization of Drive Tests MIB Master Information Block MME Mobility Management Entity MSC Mobile Switching Center NPDCCH Narrowband Physical Downlink Control Channel NR New Radio OCNG OFDMA Channel Noise Generator OFDM Orthogonal Frequency Division Multiplexing OFDMA Orthogonal Frequency Division Multiple Access OSS Operations Support System OTDOA Observed Time Difference of Arrival O&M Operation and Maintenance PBCH Physical Broadcast Channel P-CCPCH Primary Common Control Physical Channel PCell Primary Cell PCFICH Physical Control Format Indicator Channel PDCCH Physical Downlink Control Channel PDCP Packet Data Convergence Protocol PDP Power Delay Profile PDSCH Physical Downlink Shared Channel PGW Packet Gateway PHICH Physical Hybrid-ARQ Indicator Channel PLMN Public Land Mobile Network PMI Precoding Matrix Indicator PRACH Physical Random Access Channel PRS Positioning Reference Signal PSS Primary Synchronization Signal PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel RACH Random Access Channel QAM Quadrature Amplitude Modulation RAN Radio Access Network RAT Radio Access Technology RLC Radio Link Control RLM Radio Link Monitoring RNC Radio Network Controller RNTI Radio Network Temporary Identifier

[0268] RRC Radio Resource Control RRM Radio Resource Management RS Reference Signal RSCP Received Signal Code Power RSRP Reference Symbol Received Power OR

[0269] Reference Signal Received Power

[0270] RSRQ Reference Signal Received Quality OR Reference Symbol Received Quality

[0271] RSSI Received Signal Strength Indicator RSTD Reference Signal Time Difference SCH Synchronization Channel SCell Secondary Cell SDAP Service Data Adaptation Protocol SDU Service Data Unit SFN System Frame Number SGW Serving Gateway SI System Information SIB System Information Block SNR Signal to Noise Ratio SON Self-Organizing Network SS Synchronization Signal SSS Secondary Synchronization Signal TDD Time Division Duplex TDOA Time Difference of Arrival TOA Time of Arrival TSS Tertiary Synchronization Signal TTI Transmission Time Interval UE User Equipment UL Uplink UMTS Universal Mobile Telecommunications System USIM Universal Subscriber Identity Module UTDOA Uplink Time Difference of Arrival WCDMA Wideband CDMA WLAN Wireless Local Area Network

Claims

CLAIMS1. A method performed by a communication node (12) for use in a communication network (10), the method comprising: storing (900) multiple Packet Data Convergence Protocol, PDCP, packets (24) in a transmit buffer (26) of the communication node (12); discarding (910) a PDCP packet (24) from the transmit buffer (26); making (920) a decision about whether or not the discarding of the PDCP packet (24) is to trigger transmission of a PDCP SN gap report (40) that reports one or more gaps in SNs of PDCP packets (24) from the communication node (12), wherein the decision is made based on one or more triggering criterions, wherein the one or more triggering criterions include one or more of: one or more characteristics of a PDU Set (22) to which the discarded PDCP packet (24) belongs and / or one or more characteristics of a PDU Set (22) to which another PDCP packet (24) stored in the transmit buffer (26) belongs; a number of PDU Sets (22), and / or a number of types of PDU Sets (22), to which the multiple PDCP packets (24) belong; a number of PDU Sets (22), and / or a number of types of PDU Sets (22), to which one or more PDCP packets (24) remaining in the transmit buffer (26) after discarding the PDCP packet (24) belong; or a value of a discard timer (28) for another PDCP packet (24) stored in the transmit buffer (26); and triggering or not triggering (930) transmission of the PDCP SN gap report (40) according to the decision.

2. The method of claim 1 , wherein the multiple PDCP packets (24) include at least a lower-SN PDCP packet (24) and a higher-SN PDCP packet (24), with a sequence number, SN, of the lower-SN PDCP packet (24) being lower than an SN of the higher-SN PDCP packet (24), wherein the discarded PDCP packet (24) is the higher-SN PDCP packet (24), wherein said discarding comprises discarding the higher-SN PDCP packet (24) from the transmit buffer (26) when the lower-SN PDCP packet (24) is still stored in the transmit buffer (26).

3. The method of any of claims 1-2, wherein the one or more triggering criterions include the one or more characteristics of the PDU Set (22) to which the discarded PDCP packet (24) belongs and / or the one or more characteristics of the PDU Set (22) to which anotherPDCP packet (24) stored in the transmit buffer (26) belongs, wherein the one or more characteristics of a PDU Set (22) include an importance level of the PDU Set (22) as indicated by a PDU Set Importance (PSI) indicator.

4. The method of claim 3, wherein the decision is made that the discarding of the PDCP packet (24) is not to trigger transmission of the PDCP SN gap report (40), based at least in part on the importance level of the PDU Set (22) to which the PDCP packet (24) belongs being at or lower than a threshold level.

5. The method of claim 3, wherein the multiple PDCP packets (24) include at least a lower-SN PDCP packet (24) and a higher-SN PDCP packet (24), with a sequence number, SN, of the lower-SN PDCP packet (24) being lower than an SN of the higher-SN PDCP packet (24), wherein the discarded PDCP packet (24) is the higher-SN PDCP packet (24), wherein said discarding comprises discarding the higher-SN PDCP packet (24) from the transmit buffer (26) when the lower-SN PDCP packet (24) is still stored in the transmit buffer (26), wherein the one or more triggering criterions include the one or more characteristics of the PDU Set (22) to which the higher-SN PDCP packet (24) belongs and the one or more characteristics of the PDU Set (22) to which the lower-SN PDCP packet (24) belongs.

6. The method of claim 5, wherein the decision is made that the discarding of the PDCP packet (24) is not to trigger transmission of the PDCP SN gap report (40), based at least in part on the importance level of the PDU Set (22) to which the higher-SN PDCP packet (24) belongs being less than the importance level of the PDU Set (22) to which the lower-SN PDCP packet (24) belongs.

7. The method of any of any of claims 1-6, wherein the one or more characteristics of a PDU Set (22) include: a size of the PDU Set (22); and / or a type of traffic conveyed by PDCP packets (24) that belong to the PDU Set (22).

8. The method of any of claims 1-7, wherein the one or more triggering criterions include the number of PDU Sets (22) to which the multiple PDCP packets (24) belong.

9. The method of any of claims 1-8, wherein the one or more triggering criterions include the number of types of PDU Sets (22) to which the multiple PDCP packets (24) belong, wherein different types of PDU Sets (22) have different importance levels.

10. The method of any of claims 1-9, wherein the one or more triggering criterions include the value of the discard timer for another PDCP packet (24) stored in the transmit buffer (26), wherein the decision is made that: the discarding of the PDCP packet (24) is to trigger transmission of the PDCP SN gap report (40), based on the value of the discard timer for each other PDCP packet (24) stored in the transmit buffer (26) being greater than a threshold; or the discarding of the PDCP packet (24) not is to trigger transmission of the PDCP SN gap report (40), based on the value of the discard timer for each other PDCP packet (24) stored in the transmit buffer (26) being less than the threshold.

11. The method of any of claims 1-10, wherein said discarding is performed based on detecting expiration of a discard timer for the PDCP packet (24), wherein the method further comprises: receiving the PDCP packet (24) from a higher layer that is higher than a PDCP layer in a protocol stack at the communication node (12); upon receiving the PDCP packet (24) from the higher layer, starting the discard timer for the PDCP packet (24); transmitting the PDCP packet (24); storing the PDCP packet (24) in the transmit buffer (26) at the communication node (12); while the discard timer for the PDCP packet (24) is running, monitoring for reception of a PDCP status report indicating successful delivery of the PDCP packet (24), wherein the communication node (12) is configured to stop the discard timer for the PDCP packet (24) upon receiving a PDCP status report indicating successful delivery of the PDCP packet (24); and detecting expiration of the discard timer for the PDCP packet (24) before reception of any PDCP status report indicating successful delivery of the PDCP packet (24); wherein discarding the PDCP packet (24) comprises discarding the first PDCP packet (24) from the transmit buffer (26).

12. The method of claim 11 , wherein the multiple PDCP packets (24) include at least a lower-SN PDCP packet (24) and a higher-SN PDCP packet (24), with a sequence number, SN, of the lower-SN PDCP packet (24) being lower than an SN of the higher-SN PDCP packet (24), wherein the discarded PDCP packet (24) is the higher-SN PDCP packet (24), wherein the method further comprises receiving the higher-SN PDCP packet (24) from thehigher layer after receiving the lower-SN PDCP packet (24) from the higher layer, and starting a discard timer for the lower-SN PDCP packet (24) before having started the discard timer for the higher-SN PDCP packet (24), wherein the discard timer for the higher-SN PDCP packet (24) is started with a value that is smaller than a value with which the discard timer for the lower-SN PDCP packet (24) is started, wherein expiration of the discard timer for the higher-SN PDCP packet (24) is detected also before expiration of the discard timer for the lower-SN PDCP packet (24) and before reception of any PDCP status report indicating successful delivery of the lower-SN PDCP packet (24), such that expiration of the discard timer for the higher-SN PDCP packet (24) is detected while the discard timer for the lower-SN PDCP packet (24) is still running.

13. A method performed by a communication node (12) for use in a communication network (10), the method comprising: discarding (1000) one or more Packet Data Convergence Protocol, PDCP, packets (24) from a transmit buffer (26) within which is stored multiple PDCP packets (24); based on said discarding, generating (1010) a PDCP sequence number, SN, gap report (40) that reports one or more gaps in SNs of PDCP packets (24) from the communication node (12), wherein said generating comprises determining a content of the PDCP SN gap report (40) based on one or more content determination criterions, wherein the one or more content determination criterions include one or more of: for each of one or more of the one or more discarded PDCP packets (24), one or more characteristics of a PDU Set (22) to which the discarded PDCP packet (24) belongs; for each of one or more non-discarded PDCP packets (24) that are not discarded from the transmit buffer (26), one or more characteristics of a PDU Set (22) to which the non-discarded PDCP packet (24) belongs; for each of one or more non-discarded PDCP packets (24) that are not discarded from the transmit buffer (26), a value of a discard timer (28) for the non-discarded PDCP packet (24); a number of PDU Sets (22), and / or a number of types of PDU Sets (22), to which the multiple PDCP packets (24) belong; or a number of PDU Sets (22), and / or a number of types of PDU Sets (22), to which one or more non-discarded PDCP packets (24) that are not discarded from the transmit buffer (26) belong; andtransmitting (1020) the generated PDCP SN gap report (40).

14. The method of claim 13, wherein multiple PDCP packets (24) are discarded from the transmit buffer (26), and wherein determining the content of the PDCP SN gap report (40) comprises determining, based on the one or more content determination criterions, for which of the multiple discarded PDCP packets (24) the PDCP SN gap report (40) is to report gaps.

15. The method of claim 14, wherein said determining comprises determining, based on the one or more content determination criterions, a proper subset of the multiple discarded PDCP packets (24) for which the PDCP SN gap report (40) is to report gaps, wherein the PDCP SN gap report (40) is generated after discarding of all of the multiple PDCP packets (24), but reports gaps corresponding to less than all of the multiple PDCP packets (24) discarded.

16. The method of any of claims 14-15, wherein said determining is performed as part of determining the content of each of two or more PDCP SN gap reports (40) across which reporting of gaps corresponding to the multiple PDCP packets (24) discarded is split.

17. The method of claim 16, wherein the two or more PDCP SN gap reports (40) include first and second PDCP SN gap reports (40), wherein the first PDCP SN gap report (40) reports gaps corresponding to a first proper subset of the multiple PDCP packets (24) discarded with SNs below a threshold SN, and the second PDCP SN gap report (40) reports gaps corresponding to a second proper subset of the multiple PDCP packets (24) with SNs above the threshold SN.

18. The method of claim 17, wherein the threshold SN is an SN of a non-discarded PDCP packet (24) in the transmit buffer (26).

19. The method of claim 18, wherein the first and second subsets each include PDCP packets (24) that belong to a PDU Set (22) with an importance level lower than a threshold level, and wherein the non-discarded PDCP packet (24) with the threshold SN belongs to a PDU Set (22) with an importance level that equals or is above the threshold level.

20. The method of any of claims 13-19, wherein said determining comprises, determining based on the one or more content determination criterions, whether or that reporting of gaps corresponding to the multiple PDCP packets (24) discarded is to be split across two or more PDCP SN gap reports (40).

21. The method of claim 20, wherein the one or more content determination criterions include, for each of one or more of the one or more discarded PDCP packets (24), an importance level of a PDU Set (22) to which the discarded PDCP packet (24) belongs, and wherein said determining comprises determining, based on how many discarded packets (24) belong to a PDU Set (22) with an importance level lower than a threshold level, whether or that reporting of gaps corresponding to the multiple PDCP packets (24) discarded is to be split across two or more PDCP SN gap reports (40).

22. The method of any of claims 13-21 , further comprising receiving signaling indicating a maximum number of discarded PDCP packets (24) for which a PDCP SN gap report (40) is to report gaps.

23. The method of any of claims 13-22, wherein the one or more content determination criterions further include a number of the one or more PDCP packets (24) discarded from the transmit buffer (26).

24. The method of any of claims 20-30, wherein the one or more content determination criterions include one or more of: for each of one or more of the one or more discarded PDCP packets (24), one or more characteristics of a PDU Set (22) to which the discarded PDCP packet (24) belongs; and / or for each of one or more non-discarded PDCP packets (24) that are not discarded from the transmit buffer (26), one or more characteristics of a PDU Set (22) to which the non-discarded PDCP packet (24) belongs.

25. The method of claim 24, wherein the one or more characteristics of a PDU Set (22) include an importance level of the PDU Set (22) as indicated by a PDU Set Importance (PSI) indicator.

26. The method of claim 25, wherein said determining comprises determining, based on at least a threshold number of discarded PDCP packets (24) belonging to a PDU Set (22) with an importance level lower than a threshold level, the content of the PDCP SN gap report (40) to include SNs of a proper subset of the discarded PDCP packets (24) so as to report gaps corresponding to the proper subset of the discarded PDCP packets (24), wherein the proper subset of the discarded PDCP packets (24) includes PDCP packets (24) with SNs up to a threshold SN corresponding to a selected non-discarded PDCP packet (24) not discardedfrom the transmit buffer (26), wherein the selected non-discarded PDCP packet (24) belongs to a PDU Set (22) with an importance level equal to or above the threshold level.

27. A communication node (12) for use in a communication network (10), the communication node (12) configured to: store multiple Packet Data Convergence Protocol, PDCP, packets (24) in a transmit buffer (26) of the communication node (12); discard a PDCP packet (24) from the transmit buffer (26); make a decision about whether or not the discarding of the PDCP packet (24) is to trigger transmission of a PDCP SN gap report (40) that reports one or more gaps in SNs of PDCP packets (24) from the communication node (12), wherein the decision is made based on one or more triggering criterions, wherein the one or more triggering criterions include one or more of: one or more characteristics of a PDU Set (22) to which the discarded PDCP packet (24) belongs and / or one or more characteristics of a PDU Set (22) to which another PDCP packet (24) stored in the transmit buffer (26) belongs; a number of PDU Sets (22), and / or a number of types of PDU Sets (22), to which the multiple PDCP packets (24) belong; a number of PDU Sets (22), and / or a number of types of PDU Sets (22), to which one or more PDCP packets (24) remaining in the transmit buffer (26) after discarding the PDCP packet (24) belong; or a value of a discard timer for another PDCP packet (24) stored in the transmit buffer (26); and trigger or not trigger transmission of the PDCP SN gap report (40) according to the decision.

28. The communication node (12) of claim 27, configured to perform the method of any of claims 2-12.

29. A communication node (12) for use in a communication network (10), the communication node (12) configured to: discard one or more Packet Data Convergence Protocol, PDCP, packets (24) from a transmit buffer (26) within which is stored multiple PDCP packets (24); based on said discarding, generate a PDCP sequence number, SN, gap report (40) that reports one or more gaps in SNs of PDCP packets (24) from the communication node (12), wherein said generating comprises determining acontent of the PDCP SN gap report (40) based on one or more content determination criterions, wherein the one or more content determination criterions include one or more of: for each of one or more of the one or more discarded PDCP packets (24), one or more characteristics of a PDU Set (22) to which the discarded PDCP packet (24) belongs; for each of one or more non-discarded PDCP packets (24) that are not discarded from the transmit buffer (26), one or more characteristics of a PDU Set (22) to which the non-discarded PDCP packet (24) belongs; for each of one or more non-discarded PDCP packets (24) that are not discarded from the transmit buffer (26), a value of a discard timer for the non-discarded PDCP packet (24); a number of PDU Sets (22), and / or a number of types of PDU Sets (22), to which the multiple PDCP packets (24) belong; or a number of PDU Sets (22), and / or a number of types of PDU Sets (22), to which one or more non-discarded PDCP packets (24) that are not discarded from the transmit buffer (26) belong; and transmit the generated PDCP SN gap report (40).

30. The communication node (12) of claim 29, configured to perform the method of any of claims 14-26.

31. A computer program comprising instructions which, when executed by at least one processor of a communication node (12), causes the communication node (12) to perform the method of any of claims 1-26.

32. A carrier containing the computer program of claim 31 , wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

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