Improved radio link failure triggering

Abstract

The present disclosure is related to methods and devices for facilitating triggering of RLF for an RLC entity in a wireless communication system. A method performed by a UE comprises: determining that a retransmission count for a first RLC entity of a first bearer of a group of bearers has exceeded a threshold; determining that a retransmission count for a second RLC entity of a second bearer associated with the group of bearers has not exceeded a threshold; and increasing a priority level of the first bearer.

Description

[0001] IMPROVED RADIO LINK FAILURE TRIGGERING

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS)

[0003] This application claims priority to the U.S. Provisional Patent Application No.

[0004] 63 / 778,014, entitled “RADIO LINK FAILURE TRIGGERING", filed on March 26, 2025, which is incorporated herein by reference in its entirety.

[0005] Technical Field

[0006] The present disclosure relates to methods and devices for facilitating triggering of Radio Link Failure (RLF) for a Radio Link Control (RLC) entity in a wireless communication system.

[0007] Background

[0008] Radio link failure (RLF) functionality targets situation where a User Equipment (UE) has issues to communicate with a base station, the UE shall detect the issue and take appropriate action.

[0009] It is important that the UE can accurately detect problems and take actions without delay, but it is also important that the UE do not trigger RLF when there is congestion due to many users sending high amount of data.

[0010] Third Generation Partnership Program (3 GPP) Technical Specification (TS) 38.300 V18.5.0 (2025-03-21) “NR; NR and NG-RAN Overall Description” in clause 9.2.7 indicates that: The UE declares Radio Link Failure (RLF) when one of the following criteria are met:

[0011] - Expiry of a radio problem timer started after indication of radio problems from the physical layer (if radio problems are recovered before the timer is expired, the UE stops the timer); or

[0012] - Expiry of a timer started upon triggering a measurement report for a measurement identity for which the timer has been configmed while another radio problem timer is running; or

[0013] - Random access procedure failure; or

[0014] - RLC failure; or

[0015] - Detection of consistent uplink LBT failures for operation with shared spectrum channel access as described in 5.6.1; or

[0016] - For IAB-MT, the reception of a BH RLF indication received from its parent node.

[0017]

[0018] The part about Radio Link Control (RLC) failure is covered in the Radio Resource Control (RRC) specification TS 38.331 v!8.5.0 (2025-03-21) and in RLC TS 38.322 v!8.2.0 (2024-12-20). In TS 38.331, the RRC specification describes RLF detection in clause 5.3.10.3 due to RLC failure as reaching the maximum number of retransmissions:

[0019] 5.3.10.3 Detection of radio link failure

[0020] The UE shall:

[0021] 1> if any DAPS bearer is configured and T304 is running:

[0022] 2> upon T310 expiry in source SpCell; or

[0023] 2> upon random access problem indication from source MCG MAC; or

[0024] 2> upon indication from source MCG RLC that the maximum number of retransmissions has been reached; or

[0025] 2> upon consistent uplink LBT failure indication from source MCG MAC:

[0026] 3> consider radio link failure to be detected for the source MCG i.e. source RLF;

[0027] 3> suspend the transmission and reception of all DRBs and multicast MRBs in the source MCG; 3> reset MAC for the source MCG;

[0028] 3> release the source connection.

[0029] 1> else:

[0030] 2> during a DAPS handover: the following only applies for the target PCell;

[0031] 2> upon T310 expiry in PCell; or

[0032] 2> upon T312 expiry in PCell; or

[0033] 2> upon random access problem indication from MCG MAC while neither T300, T301, T304, T311 nor T319 are running and SDT procedure is not ongoing; or

[0034] 2> upon indication from MCG RLC that the maximum number of retransmissions has been reached while SDT procedure is not ongoing; or

[0035] 2> if connected as an lAB-node, upon BH RLF indication received on BAP entity from the MCG; or 2> upon consistent uplink LBT failure indication from MCG MAC while T304 is not running:

[0036] 3 > if the indication is from MCG RLC and CA duplication is configmed and activated for MCG, and for the corresponding logical channel allowedServingCells only includes SCell(s):

[0037] 4> initiate the failure information procedure as specified in 5.7.5 to report RLC failure.

[0038] 3> else:

[0039] 4> consider radio link failure to be detected for the MCG, i.e. MCG RLF;

[0040] 4> discard any segments of segmented RRC messages stored according to 5.7.6.3;

[0041]

[0042] The UE shall:

[0043] 1> upon T310 expiry in PSCell; or

[0044] 1> upon T312 expiry in PSCell; or

[0045] 1> upon random access problem indication from SCG MAC; or

[0046] 1> upon indication from SCG RLC that the maximum number of retransmissions has been reached; or 1> if connected as an lAB-node, upon BH RLF indication received on BAP entity from the SCG; or

[0047] 1> upon consistent uplink LBT failure indication from SCG MAC:

[0048] 2> if the indication is from SCG RLC and CA duplication is configured and activated for SCG, and for the corresponding logical channel allowedServingCells only includes SCell(s):

[0049] 3> initiate the failure information procedure as specified in 5.7.5 to report RLC failure.

[0050]

[0051] The reaching of maximum number of RLC retransmissions is described in TS 38.322 V18.2.0, clause 5.3.2:

[0052] 5.3.2 Retransmission

[0053] The transmitting side of an AM RLC entity can receive a negative acknowledgement (notification of reception failure by its peer AM RLC entity) for an RLC SDU or an RLC SDU segment by the following:

[0054] - STATUS PDU from its peer AM RLC entity.

[0055] When receiving a negative acknowledgement for an RLC SDU or an RLC SDU segment by a STATUS PDU from its peer AM RLC entity, the transmitting side of the AM RLC entity shall:

[0056] - if the SN of the corresponding RLC SDU falls within the range TX Next Ack <= SN < = the highest SN of the AMD PDU among the AMD PDUs submitted to lower layer:

[0057] - consider the RLC SDU or the RLC SDU segment for which a negative acknowledgement was received for retransmission.

[0058] When an RLC SDU or an RLC SDU segment is considered for retransmission, the transmitting side of the AM RLC entity shall:

[0059] - if the RLC SDU or RLC SDU segment is considered for retransmission for the first time:

[0060] - set the RETX COUNT associated with the RLC SDU to zero.

[0061] - else, if it (the RLC SDU or the RLC SDU segment that is considered for retransmission) is not pending for retransmission already and the RETX COUNT associated with the RLC SDU has not been incremented due to another negative acknowledgment in the same STATUS PDU:

[0062] increment the RETX COUNT.

[0063]

[0064] - if RETX_COUNT = maxRetxThreshold.

[0065] - indicate to upper layers that max retransmission has been reached.

[0066] When retransmitting an RLC SDU or an RLC SDU segment, the transmitting side of an AM RLC entity shall: - if needed, segment the RLC SDU or the RLC SDU segment;

[0067] - form a new AMD PDU which will fit within the total size of AMD PDU(s) indicated by lower layer at the particular transmission opportunity;

[0068] - submit the new AMD PDU to lower layer.

[0069] When forming a new AMD PDU, the transmitting side of an AM RLC entity shall:

[0070] - only map the original RLC SDU or RLC SDU segment to the Data field of the new AMD PDU;

[0071] - modify the header of the new AMD PDU in accordance with the description in clause 6.2.2.4;

[0072] - set the P field according to clause 5.3.3.

[0073]

[0074] Radio Link Control protocol is also described in TS 38.322 clause 5.2.2.2.1:

[0075] When receiving an UMD PDU from lower layer, the receiving UM RLC entity shall:

[0076] - either deliver the UMD PDU to upper layer after removing the RLC header, discard the received UMD PDU, or place it in the reception buffer (see clause 5.2.2.2.2);

[0077] - if the received UMD PDU was placed in the reception buffer:

[0078] - update state variables, reassemble and deliver RLC SDUs to upper layer and start / stop t-Reassembly as needed (see clause 5.2.2.2.3).

[0079] When t-Reassembly expires, the receiving UM RLC entity shall:

[0080] - update state variables, discard RLC SDU segments and start t-Reassembly as needed (see clause 5.2.2.2.4).

[0081]

[0082] And in clause 5.3.3.3 of TS 38.322:

[0083] 5.3.3.3 Reception of a STATUS report

[0084] Upon reception of a STATUS report from the receiving RLC AM entity the transmitting side of an AM RLC entity shall:

[0085] - if the STATUS report comprises a positive or negative acknowledgement for the RLC SDU with sequence number equal to POLL SN:

[0086] - if t-PollRetransmit is running:

[0087] - stop and reset t-PollRetransmit.

[0088]

[0089] Summary

[0090] There currently exist certain challenges. A problem is that some User Equipments (UEs)will trigger Radio Link Failure (RLF) when there is congestion in the system, that is, when lack of successful data transmission is mainly due to (many) users transmitting much data. For example, when a UE is configured with multiple radio bearers / channels, and each bearer / channel will have a separate Radio Link Control (RLC) entity with a separate set of RLC parameters and counters, and these bearers / channels have different priorities, then one high priority bearer / channel can starve out a low priority bearer / channel. In this case the low priority bearer / channel will trigger an indication (from RLC) to higher layers (to Radio Resource Control - RRC) indicating that max retransmission has been reached and RRC will then trigger RLF for the UE.

[0091] Another problem with the existing method for triggering RLF is that different services may have different acceptance for how long a traffic interruption may be acceptable before triggering an RLF.

[0092] Yet another problem is that there is no mechanism in RLC to trigger an RLF when RLC Unacknowledged Mode (UM) is used.

[0093] Therefore, to address or at least partially alleviate one or more of the above issues, some embodiments of the present disclosure are provided.

[0094] Some embodiments of the present disclosure provide for a method and device that facilitate triggering of Radio Link Failure (RLF) for a Radio Link Control (RLC) entity in order to prevent one bearer / channel from triggering RLF when there are other bearers / channels that work fine. The disclosed methods also provide more methods for controlling triggering of RLF.

[0095] According to a first aspect of the present disclosure, a method performed by a User Equipment device, UE, is provided. The method comprises determining that a retransmission count for a first RLC entity of a first bearer of a group of bearers has exceeded a threshold. The method further comprises determining that a retransmission count for a second RLC entity of a second bearer associated with the group of bearers has not exceeded a threshold. The method further comprises increasing a priority level of the first bearer. One or more further embodiments of the first aspect will be provided in the Detailed Description below.

[0096] According to a second aspect of the present disclosure, a user equipment device, UE, is provided. The UE comprises processing circuitry. The circuitry is configured to cause the UE to determine that a retransmission count for a first Radio Link Control, RLC, entity of a first bearer of a group of bearers has exceeded a threshold. The circuitry is further configured to cause the UE to determine that a retransmission count for a second RLC entity of a second bearer associatedwith the group of bearers has not exceeded a threshold. The circuitry is further configured to cause the UE to increase a priority level of the first bearer. In some embodiments, the processing circuitry is further configured to cause the UE to perform any of the method of the first aspect.

[0097] According to a third aspect of the present disclosure, a computer program comprising instructions is provided. The instructions, when executed by at least one processor, cause the at least one processor to carry out any of the methods of the first aspect.

[0098] According to a fourth aspect of the present disclosure, a carrier containing the computer program of the third aspect is provided. In some embodiments, the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

[0099] With some embodiments of the present disclosure, there will not be an RLF triggered if one bearer / channel is starved while there is another bearer / channel that works fine. This will decrease the number of erroneous RLFs, especially in overload conditions where the RLFs can lead to increase load on the random access channel (that may in turn lead to increased number of UEs experiencing long delays, as the random access (RA) transmissions are done with very high priority, which may starve transmissions of lower priority bearers / channels carrying normal user data leading to an avalanche of random access attempts). This also means that the existing parameters for logical channel prioritization in Medium Access Control (MAC) (prioritized bit rate and bucket size duration) can be used to control quality of service instead of ensuring there is a minimum rate for the RLC status reports to go through.

[0100] Brief Description of the Drawings

[0101] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0102] Figure 1 shows a flowchart of a method to facilitate triggering of Radio Link Failure (RLF) for a Radio Link Control (RLC) entity in accordance with some embodiments of the present disclosure;

[0103] Figure 2 shows an example of a communication system in accordance with some embodiments of the present disclosure;

[0104] Figure 3 shows another example of a communication system according to some embodiments of the present disclosure;Figure 4 shows a wireless device, which may be configured to operate in the communication system of Figure 2 or in the communication system of Figure 3;

[0105] Figure 5 shows a network node in accordance with some embodiments of the present disclosure; and

[0106] Figure 6 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments of the present disclosure may be virtualized.

[0107] Detailed Description

[0108] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0109] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0110] In some embodiments of the present disclosure, the terms “bearer(s)”, “radio bearer(s)”, “RLC bearer(s)”, “RLC channel(s)”, “logical channel(s)”, and “Quality of Service (QoS) flow(s)” may be used interchangeably because there may be a 1-to-l mapping between them even when some of them may refer to different concepts in different sub-layers.

[0111] There currently exist certain challenge(s). It may be that some User Equipments (UEs) trigger Radio Link Failure (RLF) when there is congestion in the system, that is, when lack of successful data transmission is mainly due to (many) users transmitting much data.

[0112] For example, when a UE is configured with multiple radio bearers / channels, and each bearer / channel will have a separate Radio Link Control (RLC) entity with a separate set of RLC parameters and counters, and these bearers / channels have different priorities, then one high priority bearer / channel can starve out a low priority bearer / channel.

[0113] In this case the low priority bearer / channel will trigger an indication (from RLC) to higher layers (to Radio Resource Control - RRC) (indicate to upper layers that max retransmission has been reached) and RRC will then trigger RLF for the UE.Another problem with the existing method for triggering RLF is that different services may have different acceptance for how long a traffic interruption may be acceptable before triggering an RLF. For instance, it may be important for some critical services to trigger RLF quickly to try and recover the connection, rather than waiting for long without triggering RLF.

[0114] Another problem is that there is no mechanism in RLC to trigger an RLF when RLC Unacknowledged Mode (UM) is used.

[0115] The existing parameters for logical channel prioritization (LCP) in Medium Access Control (MAC) (prioritised bit rate and bucket size duration) are today used to ensure there is a minimum rate for the RLC status report, while these parameters could be used to control the quality of service.

[0116] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. The basic idea is to prevent one bearer / channel from triggering RLF when there are other bearers / channels that work fine, and also provide more methods for controlling triggering of RLF.

[0117] Instead of triggering RLF per RLC bearer / channel for reaching max number of RLC retransmissions, a “RLC failure” is defined per MAC entity (or any grouping of RLC entities) such that the RLC failure is not triggered for one bearer / channel while there is another RLC bearer / channel connected to the same MAC entity that works fine. The MAC entity here is just an example of a convenient grouping of the RLC entities, any other grouping of the RLC entities is possible.

[0118] Proposed herein is an alternative method, that by increasing the priority of a bearer / channel that risk triggering RLF while some other bearer / channel works fine, triggering unwanted RLFs can also be avoided. Further some problem cases can be avoided by allowing RLC STATUS reports to bypass the LCP in MAC (that is, STATUS reports get a very high priority). For RLC UM bearers / channels, RLF triggering is added when Hybrid Automatic Repeat Request (HARQ) is not working properly.

[0119] In some embodiments, the RLC failure can be triggered with different time intervals based on different Fifth Generation (5G) Quality of Service (QoS) Indicators (5 Qis) and hence based on different services. This method therefore allows configuring different 5QIs with different time intervals during which RLF is triggered if no response has been detected during this time interval. With this method, it will for instance be possible to ensure that if a certain service is not getting any response from the network within a certain defined time period, RLF can be triggered earlierto try and recover the connection, rather than trying to wait for too long and then trigger RLE In the same way, if a less critical service does not get a response it may be less urgent to trigger an RLF triggering of RLC failure per group of RLC entities instead of per RLC bearer / channel / entity.

[0120] Certain embodiments may provide one or more of the following technical advantage(s). The advantage is that there will not be an RLF triggered if one bearer / channel is starved while there is another bearer / channel that works fine.

[0121] This will decrease the number of erroneous RLFs, especially in overload conditions where the RLFs can lead to increase load on the random access channel (that may in turn lead to increased number of UEs experiencing long delays, as the RA transmissions are done with very high priority, which may starve transmissions of lower priority bearers / channels carrying normal user data leading to an avalanche of random access attempts).

[0122] This also means that the existing parameters for logical channel prioritisation in MAC (prioritised bit rate and bucket size duration) can be used to control quality of service instead of ensuring there is a minimum rate for the RLC status reports to go through.

[0123] Control of Polling

[0124] In one embodiment, when an RLC entity receives a STATUS report and there are other RLC entities in the UE that has a running t-pollRe transmit, the UE shall restart t-pollRetransmit for the other RLC entities (the other RLC entities can be all RLC entities in the UE or a subgroup of RLC entities for example the RLC entities that belong to the same Cell Group as the RLC entity receiving a STATUS report, that is the Master Cell Group or the Secondary Cell Group).

[0125] The restarting of t-pollRe transmit, if running, for the other RLC entities can be at the time when the RLC entity receiving the STATUS report is to stop and reset the t-pollRetransmit of that RLC entity, if t-pollRetransmit is running (or when it would stop and reset it, if it is not running).

[0126] Control of Retransmission Counting

[0127] In one embodiment, when an RLC entity receives a STATUS report, the UE shall reset RETX COUNT to zero for all “RLC SDU or an RLC SDU segment considered for retransmission” of other RLC entities (besides the RLC entity the STATUS report is received for) at the time when the RLC entity receiving the STATUS report is to stop and reset the t-pollRetransmit of that RLC entity, if t-pollRetransmit is running (or when it would stop and reset it, if it is not running).

[0128] The “other RLC entities” in this embodiment may be all RLC entities that the UE has, or a subgroup of the RLC entities, for example the RLC entities that belong to the same Cell Group asthe RLC entity receiving a STATUS report, that is the Master Cell Group or the Secondary Cell Group.

[0129] Control of Data Priority

[0130] In one embodiment, when the UE increases the RETX COUNT for one bearer / channel in RLC entity A, if the RETX COUNT is larger than a threshold and there are other RLC entities in the UE that has higher data priority (used for LCP procedure in MAC to allocate resources for a grant), the UE may increase the priority of the data of RLC entity A.

[0131] The other RLC entities can be all RLC entities in the UE or a subgroup of RLC entities, for example the RLC entities that belong to the same Cell Group as the RLC entity increasing RETX COUNT, that is the Master Cell Group or the Secondary Cell Group.

[0132] The data priority may be reset to normal priority when data for that bearer / channel is sent, for example when a positive STATUS ACK is received for the data that triggered retransmissions.

[0133] Control of Retransmission Counting

[0134] In one embodiment, the UE has one single RETX COUNT which is incremented whenever the t-pollRetransmit expires for any PDU. The counter is reset to 0 whenever a STATUS report for any RLC PDU is received.

[0135] Prioritizing Control Data

[0136] Below is a proposed update in the MAC standard Third Generation Partnership Program (3GPP) Technical Specification (TS) 38.321 V18.5.0 (2025-03-21) that is to ensure that RLC status reports will be prioritized over any other data. The UE can (temporarily when problems are detected as described in other embodiments or permanently) allow RLC STATUS reports to bypass the LCP procedure before adding data from other logical channels.

[0137] The proposed addition is underlined in clause 5, 4, 3, 1,3:

[0138] BEGIN EXCERPT

[0139] 5.4.3.1.3 Allocation of resources

[0140] Before the successful completion of the Random Access procedure initiated for DAPS handover, the target MAC entity shall not select the logical channel(s) corresponding to non-DAPS DRB(s) for the uplink grant received in a Random Access Response or the uplink grant for the transmission of the MSGA payload. The source MAC entity shall select only the logical channel(s) corresponding to DAPS DRB(s) during DAPS handover.

[0141] The MAC entity shall, when a new transmission is performed:

[0142] 1> allocate resources to the logical channels as follows:

[0143]

[0144] 2> to send RLC status reports triggered for any logical channels;

[0145] 2> logical channels selected in clause 5.4.3.1.2 for the UL grant with / i / > 0 are allocated resources in a decreasing priority order. If the PBR of a logical channel is set to infinity, the MAC entity shall allocate resources for all the data that is available for transmission on the logical channel before meeting the PBR of the lower priority logical channel(s);

[0146] END EXCERPT

[0147] Radio Link Failure For RLC Unacknowledged Mode

[0148] In one embodiment a radio link failure (RLF) is detected when the maximum number of consecutive HARQ failures is exceeded, i.e. max number of consecutive NACKs or Discontinuous Transmission (DTX) for multiple HARQs.

[0149] In one embodiment an RLF can be detected on both gNB and UE sides. A gNB can detect an RLF when multiple consecutive DTXs are detected for either uplink transmission or HARQ feedback of downlink transmission. UE can detect an RLF when multiple DL transmission decoding errors are detected.

[0150] Another embodiment describes frequent t-Reassembly expiration in RLC UM indicates persistent radio link issues, for example if some RLC entities in the UE (for example the RLC entities in the same Cell Group as MCG or SCG, or all RLC entities) count the number of t-Reassembly expiry within a time period and this count is above a threshold, then RLF is triggered.

[0151] Another embodiment describes that an RLF can occur when a beam recovery procedure fails for one or many times and more than a preconfigured count threshold.

[0152] One embodiment describes that an RLF can be defined per logical channel or per MAC entity.

[0153] As one embodiment, compare the number of received packets and the number of missing packets during some time interval, and if the ratio is too big, an RLF is triggered. This can for instance be done as follows in the RLC receiver:

[0154] At regular intervals T do the following:

[0155] 1. Set a counter TotRec to be the total number of received RLC PDUs in the previous time interval.

[0156] 2. Set a counter TotMissing to be the total number of not received RLC PDUs in the previous time interval.

[0157] This can be calculated by taking the difference between the latest received Packet Data Convergence Protocol (PDCP) sequence number SN and the latest receivedPDCP sequence number at start of the previous time interval StartSN, and subtract the TotRec counter.

[0158] 3. Set StartSN to the latest received PDCP Sequence number.

[0159] 4. Calculate the ratio of missing RLC PDUs: MissingRatio = TotMissing / (TotReceived + TotMissing).

[0160] 5. If MissingRatio exceeds a certain configuration ratio of missing packets (MaxRatioOfMissingRlcPdus), an RLF is triggered.

[0161] Figure 1 shows a flowchart of a method to facilitate triggering of Radio Link Failure (RLF) for a Radio Link Control (RLC) entity in accordance with some embodiments of the present disclosure.

[0162] At step 102, the method includes determining that a retransmission count for a first RLC entity of a first bearer / channel of a group of bearers / channels has exceeded a threshold. In an embodiment, the group of bearers / channels share a MAC entity.

[0163] At step 104, the method includes determining that a retransmission count for a second RLC entity of a second bearer / channel associated with the group of bearers / channels has not exceeded a threshold.

[0164] At step 106, the method includes increasing a priority level of the first bearer / channel. In an embodiment, the priority level of the first bearer / channel is reset subsequent to receiving an acknowledgement after transmission of data associated with the retransmission count for the first RLC entity exceeding a threshold. In an embodiment, the increasing the priority level of the first bearer / channel comprises increasing a retransmission count threshold for the first bearer / channel if the second bearer / channel has a higher priority.

[0165] At step 108, the method optionally includes enabling RLC status reports associated with the group of bearers / channels to bypass logical channel prioritization.

[0166] At step 110, the method includes declaring an RLF. In an embodiment, the declaring an RLF occurs when retransmission counts for RLC entities of all bearers / channels of the group of bearers / channels exceed a threshold. In an embodiment, the declaring or declaring an RLF occurs when a maximum number of consecutive Hybrid Automatic Repeat Request, HARQ, failures is exceeded. In an embodiment, the declaring or declaring an RLF occurs in response to a number of downlink transmission decoding errors exceeds a threshold.In an embodiment, the declaring or declaring an RLF occurs when a beam recovery procedure fails for at least one of one time, a plurality of times; or a number of times exceeding a threshold.

[0167] In an embodiment, an RLF is defined per logical channel or per MAC entity.

[0168] In an embodiment, the UE comprises a single retransmission counter that is incremented whenever a t-pollRetransmit expires for any Protocol Data Unit (PDU).

[0169] In an embodiment, the other RLC entities comprise other RLC entities that belong to the same cell group as the RLC entity receiving the status report.

[0170] In an embodiment, in response to the first RLC entity receiving a status report, the UE resets retransmission counts to zero for all RLC Service Data Units, SDUs, or all RLC SDU segments considered for retransmission of other RLC entities.

[0171] In an embodiment, in response to the first RLC entity receiving a status report and there are other RLC entities in the UE that have running t-pollRe transmit, the UE restarts t-pollRetransmit for the other RLC entities.

[0172] In an embodiment, the method further includes triggering an RLF when a number of t-Reassembly expiries in RLC Unacknowledged Mode, UM, within a time period is above a threshold.

[0173] In an embodiment, the method further includes triggering an RLF when a ratio of a number of missing packets to a sum of the number of missing packets and a number of received packets during a time interval is above a threshold.

[0174] Figure 2 shows an example of a communication system 200 in accordance with some embodiments.

[0175] In the example, the communication system 200 includes a telecommunications network 202 that includes an access network 204, such as a radio access network (RAN), and a core network 206, which includes one or more core network nodes 208. The access network 204 includes one or more access network nodes or base stations of various types, access network nodes 210A and 210B are depicted (which may be collectively referred to as network nodes 210), or any other similar 3rdGeneration Partnership Project (3GPP) access nodes or non-3GPP access points (APs). Some embodiments of the access network 204 may include more than one access network technology. The network nodes 210 of access network 204 facilitate direct or indirect connection of wireless devices, also referred to as user equipments (UEs), such as by connecting UEs 212A,212B, 212C, and 212D (one or more of which may be generally referred to as UEs 212) to the core network 206 over one or more wireless connections. In an embodiment, the UEs 212 can perform the method as described in Figure 1.

[0176] Moreover, 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 telecommunications network 202 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a network node in the telecommunications network 202 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 network nodes to implement one or more functionalities of any network node in the telecommunications network 202, including one or more access network nodes 210 and / or core network nodes 208.

[0177] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU-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). An ORAN network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN network 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 O-2 interface defined by the O-RAN Alliance or comparable technologies.

[0178] The network nodes 210 facilitate direct or indirect connection of one or more UEs 212 to the core network 206 over one or more wireless connections. 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 forconveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 200 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 200 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0179] The UEs 212 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 210 and other communication devices. Similarly, the network nodes 208, 210 are arranged, capable, configured, and / or operable to communicate directly or indirectly (e.g., via other devices of telecommunications network 202) with the UEs 212 and / or with other network nodes or equipment in the telecommunications network 202 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunications network 202. More specifically, UEs 212 may send messages, data, and / or other signals to network nodes 208, 210 or other elements of the telecommunications network 202 by transmitting such signals to the relevant device directly without the signals passing through any intervening devices or by transmitting such signals to the relevant device indirectly through an intervening device (or multiple intervening devices) that then transmit the signal to the relevant device. Similarly, network nodes 208, 210 may send messages, data, and other signals to UEs 212, other network nodes 208, 210, and other devices in telecommunications network 202 directly or indirectly. As one specific example, a core network node 108 may transmit a particular message to a UE 212 by transmitting the message to an access network node 210 that will then transmit the message to the intended UE 212. Similarly, a core network node 208 may receive a particular message from a UE 212 by receiving the message from an access network node 210 that itself received the message from the UE 212.

[0180] In the depicted example, the core network 206 connects elements of the access network 204 (e.g., one or more of the network nodes 210) to one or more host computing systems, such as host 216. 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 206 includes one or more core network nodes (e.g., core network node 208) of various types, one ormore of which may be generally referred to as network nodes 208. Network nodes 208 are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, access network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 208. Example core network nodes provide functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0181] The host 216 may be under the ownership or control of a service provider other than an operator or provider of the access network 204 and / or the telecommunications network 202. The host 216 may be operated by the service provider or on behalf of the service provider. The host 216 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.

[0182] As a whole, the communication system 200 of Figure 2 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system 200 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 (Wi-Fi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (Wi-Max), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, Li-Fi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox. Moreover, the communication system 200 may be configured to support multiple different standards, protocols, or other rule sets, with individual componentssupporting all of the relevant rule sets or with different components or sub-systems within the communication system 200 supporting different standards, protocols, or rule sets.

[0183] As one example, in certain embodiments, access network 204 may contain some access network nodes 210 that support 3 GPP radio access technologies (RAT), such as LTE or NR, while other access network nodes 210 support (or the same access network nodes 210 additionally support) non-3GPP RATs, such as Wi-Fi or a proprietary RAT. As another example, telecommunications network 202 may support multiple generations of related communication standards (e.g., 4G and 5G 3GPP communication standards) and, as a result, may include an access network 204 and / or a core network 206 that supports multiple different standard generations or may include multiple access networks 204 and / or multiple core networks 206 with individual networks 204, 206 supporting different standard generations.

[0184] Telecommunications network 202 may support network slicing to provide different logical networks to different devices that are connected to the telecommunications network 202. For example, the telecommunications network 202 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.

[0185] In some examples, one or more of the UEs 212 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 204 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 204. 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).

[0186] In the example, the hub 214 communicates with the access network 204 to facilitate indirect communication between one or more UEs (e.g., UE 212C and / or 212D) and network nodes (e.g., network node 210B). In some examples, the hub 214 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 214 may be a broadband router enabling access to the core network 206 for the UEs. As another example, the hub 214 may be a controller that sends commands or instructions toone or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 210, or by executable code, script, process, or other instructions in the hub 214.

[0187] As another example, the hub 214 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 214 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 214 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 214 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 214 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0188] The hub 214 may have a constant / persistent or intermittent connection to the network node 210B. The hub 214 may also allow for a different communication scheme and / or schedule between the hub 214 and UEs (e.g., UE 212C and / or 212D), and between the hub 214 and the core network 206. In other examples, the hub 214 is connected to the core network 206 and / or one or more UEs via a wired connection. Moreover, the hub 214 may be configured to connect to an M2M service provider over the access network 204 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 210 while still connected via the hub 214 via a wired or wireless connection. In some embodiments, the hub 214 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 21 OB. In other embodiments, the hub 214 may be a nondedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 21 OB, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0189] Figure 3 is another example of a communication system 300 according to some embodiments. As used herein, the communication system 300 includes multiple access points (APs) 310 (with four exemplary APs 310A, 310B, 310C, and 310D being depicted) and multiple wireless devices, referred to in the context of communication system 300 as stations (STAs) 312 (referred to individually as STA 312A, STA 312B, STA 312C, STA 312D, and STA 312E). STA 312A is served by AP 310A in a first basic service set (BSS) 320A. STA 310B and STA 310C are served by AP 310B in a second BSS, BSS 320B. STA312D is served by AP 310C in a third BSS, BSS 320C. STA312E is served by AP 310D in a fourth BSS, BSS 320D. Stations 312 may be non-APSTAs and correspond to various kinds of wireless devices, for example, user terminals, such as mobile or stationary computing devices like smartphones, laptop computers, desktop computers, tablet computers, gaming devices, head-mounted displays (HMDs) for Augmented Reality (AR) or Virtual Reality (VR), or the like. Further, stations 312 could, for example, correspond to other kinds of equipment like smart home devices, printers, multimedia devices, data storage devices, or the like.

[0190] Each of STAs 312 may connect through a radio link to one of APs 310. For example, depending on location or channel conditions experienced by a given STA312, the STAmay select an appropriate AP and BSS for establishing the radio link. The radio link may be based on one or more orthogonal frequency-division multiplexing (OFDM) carriers from a frequency spectrum that is shared on the basis of a contention-based mechanism, e.g., an unlicensed or license exempt band like 2.4 GHz Industrial, Scientific, and Medical (ISM) band, the 5 GHz band, the 6 GHz band, or the 60 GHz band.

[0191] Each AP 310 may provide data connectivity to STAs 312 connected to a particular AP 310. As illustrated, APs 310 may be connected to a data network 330. In this way, APs 310 may also provide data connectivity between STAs 312 and other entities, e.g., to one or more servers, service providers, data sources, data sinks, user terminals, or the like. Accordingly, the radio link established between a given STA 312 and its serving AP 310 may be used for providing various kinds of services to STA 312, e.g., a voice service, a multimedia service, or other data service. Such services may be based on applications that are executed on STA312 and / or on a device linked to STA 312. By way of example, Figure 3 illustrates an application service platform 332 provided in data network 330. The application(s) executed on STA 312 and / or on one or more other devices linked to STA 312 may use the radio link for data communication with one or more other STA 312 and / or the application service platform 332, thereby enabling utilization of the corresponding service(s) at STA 312.

[0192] Figure 4 shows a wireless device 400, which may be configured to operate in communication system 200 of Figure 2 or in communication system 300 of Figure 3. The wireless device 400 may be alternatively referred to as a UE 400, like a UE 212 within the context of communication system 200, or as a station (STA) 400 or as a non-access-point station (non-AP STA) 400, like a STA 312 within the context of the communication system 300, in accordance with respective embodiments. As used herein, a wireless device refers to a device capable, configured,arranged and / or operable to communicate wirelessly with network nodes and / or other wireless devices. Examples of a wireless device 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 device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, and wireless terminal. Other examples include any type of UE identified by the 3rdGeneration Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0193] A wireless device 400 may support device-to-device (D2D) communication, for example by implementing a 3 GPP 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, wireless device 400 may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, wireless device 400 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, wireless device 400 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).

[0194] In particular embodiments, wireless device 400 includes processing circuitry 402 that is operatively coupled via a bus 404 to an input / output interface 406, a power source 408, a memory 410, a communication interface 412, and / or any other component, or any combination thereof. Certain embodiments of wireless device 400 may include all or a subset of the components shown in Figure 4. The level of integration between the components may vary from one embodiment of wireless device 400 to another. In general, in a particular embodiment of wireless device 400, processing circuitry 402, input / output interface 406, power source 408, memory 410, and communication interface 412 may, in whole or in part, represent or include physical components common to or shared by one or more of the other elements of wireless device 400. Further, certain embodiments of wireless devices 400 may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.The processing circuitry 402 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 410. The processing circuitry 402 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 402 may include multiple central processing units (CPUs).

[0195] In the example, the input / output interface 406 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 wireless device 400. 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.

[0196] In some embodiments, the power source 408 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 to supply power to circuitry or to charge an associated battery. The power source 408 may further include power circuitry for delivering power from the power source 408 itself, and / or an external power source, to the various parts of wireless device 400 via input circuitry or an interface such as an electrical power cable. Power source 408 may perform any formatting, converting, or other modification to make accessible power suitable for the respective components of the wireless device 400 to which power is supplied.

[0197] The memory 410 may be or be configured to include memory such as random accessmemory (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 410 includes one or more programs 414, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 416. The memory 410 may store, for use by wireless device 400, any of a variety of various operating systems or combinations of operating systems.

[0198] The memory 410 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 410 may allow wireless device 400 to access instructions, 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 410, which may be or comprise a device-readable storage medium.

[0199] The processing circuitry 402 may be configured to communicate with an access network or other network via or using the communication interface 412. The communication interface 412 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 422. The communication interface 412 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 wireless device or a network node in an access network). Each transceiver may include a transmitter 418 and / or a receiver 420 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 418 and receiver 420 may be coupled to one or more antennas (e.g., antenna 422) and may share circuit components, software, or firmware, or alternatively beimplemented separately.

[0200] In the illustrated embodiment, communication functions of the communication interface 412 may include cellular communication, Wi-Fi communication (e.g., according to an IEEE 802.11 family standard), 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 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.

[0201] In particular embodiments, wireless device 400 may provide an output of data captured via a sensor, through its communication interface 412, via a wireless connection to a network node, and / or in any appropriate manner. Data captured by sensors of a wireless device 400 can be communicated through a wireless connection to a network node via another wireless device 400. In particular embodiments, such 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).

[0202] As another example, wireless device 400 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, wireless device 400 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.

[0203] Wireless device 400, 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, 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 orfreezer, 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. In particular embodiments, wireless device 400 represents an loT device that 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 example embodiment of wireless device 400 shown in Figure 4.

[0204] As yet another specific example, in an loT scenario, wireless device 400 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 wireless device and / or a network node. Wireless device 400 may in this case be an M2M device, which may in a 3 GPP context be referred to as an MTC device. As one particular example, wireless device 400 may implement the 3GPP NB-IoT standard. In other scenarios, wireless device 400 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.

[0205] In practice, any number of wireless devices 400 may be used together with respect to a single use case. For example, a first wireless device 400 might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second wireless device 400 that is a remote controller operating the drone. When a user makes changes from the remote controller, the first wireless device 400 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 wireless device 400 can also include more than one of the functionalities described above. For example, wireless device 400 might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0206] Figure 5 shows a network node 500 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicatedirectly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunications network. In accordance with respective embodiments, network node 500 may be configured to operate in communication system 200 of Figure 2, like network nodes 208 or 210, or in communication system 300 of Figure 3, like an AP 310 or a station 312. 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 NRNodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU).

[0207] Network nodes 500 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. Network node 500 may be a relay node or a relay donor node controlling a relay. Network nodes 500 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).

[0208] Other examples of network nodes 500 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).

[0209] In particular embodiments, network node 500 includes a processing circuitry 502, a memory 504, a communication interface 506, and a power source 508. In general, in a particular embodiment of network node 500, processing circuitry 502, memory 504, communication interface 506, and power source 508 may, in whole or in part, represent or include physical components common to or shared by one or more of the other elements of network node 500.

[0210] The network node 500 may be composed of multiple distinct network entities (e.g., a NodeB entity and an RNC entity, or a BTS entity and a BSC entity, etc.), which may each have orutilize their own respective physical components. In certain scenarios in which the network node 500 comprises multiple such entities (e.g., BTS and BSC), one or more of the separate entities 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 500 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memories 504 or portions of memory 504 for different RATs) and some components may be reused (e.g., a same antenna 510 may be shared by different RATs). The network node 500 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 500, for example GSM, WCDMA, LTE, NR, Wi-Fi (e.g., according to an IEEE 802.11 family standard), 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 500.

[0211] The processing circuitry 502 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 components, such as the memory 504, to provide network node 500 functionality.

[0212] In some embodiments, the processing circuitry 502 includes a system on a chip (SOC). In some embodiments, the processing circuitry 502 includes one or more of radio frequency (RF) transceiver circuitry 512 and baseband processing circuitry 514. In some embodiments, the RF transceiver circuitry 512 and the baseband processing circuitry 514 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 512 and baseband processing circuitry 514 may be on the same chip or set of chips, boards, or units.

[0213] The memory 504 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, aflash 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 502. The memory 504 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 502 and utilized by the network node 500. The memory 504 may be used to store any calculations made by the processing circuitry 502 and / or any data received via the communication interface 506. In some embodiments, the processing circuitry 502 and memory 504 is integrated.

[0214] The communication interface 506 is used in wired or wireless communication of signaling and / or data with UEs, other network nodes, and / or any other network equipment. In the illustrated embodiment, communication interface 506 comprises port(s) / terminal(s) 516 to send and receive data, for example to and from a network over a wired connection. In particular embodiments, network node 400 may be capable of wireless communication and communication interface 506 may also include radio front-end circuitry 518 that may be coupled to, or in certain embodiments a part of, an antenna 510. Particular embodiments of radio front-end circuitry 518 include filter(s) 520 and amplifier(s) 522. The radio front-end circuitry 518 may be connected to an antenna 510 and processing circuitry 502. The radio front-end circuitry may be configured to condition signals communicated between antenna 510 and processing circuitry 502. The radio front-end circuitry 518 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 518 may convert the digital data into a radio signal(s) having the appropriate channel and bandwidth parameters using a combination of filters 520 and / or amplifiers 522. The radio signal(s) may then be transmitted via the antenna 510. Similarly, when receiving data, the antenna 510 may collect radio signals which are then converted into digital data by the radio front-end circuitry 518. The digital data may be passed to the processing circuitry 502. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0215] In certain alternative embodiments, network node 500 may be capable of wireless communication but does not include separate radio front-end circuitry 518, instead, the processing circuitry 502 includes radio front-end circuitry and is connected to the antenna 510. Similarly, in some embodiments, all or some of the RF transceiver circuitry 512 is part of the communicationinterface 506. In still other embodiments, the communication interface 506 includes one or more ports or terminals 516, the radio front-end circuitry 518, and the RF transceiver circuitry 512, as part of a radio unit (not shown), and the communication interface 506 communicates with the baseband processing circuitry 514, which is part of a digital unit (not shown).

[0216] The antenna 510 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 510 may be coupled to the radio front-end circuitry 518 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 510 is separate from the network node 500 and connectable to the network node 500 through one or more interfaces or ports.

[0217] The antenna 510, communication interface 506, and / or the processing circuitry 502 may be configured to perform some or all of the receiving operations and / or obtaining operations described herein as being performed by the network node 500. Any information, data, and / or signals may be received from a UE, another network node, and / or any other network equipment. Similarly, the antenna 510, the communication interface 506, and / or the processing circuitry 502 may be configured to perform some or all of the transmitting or sending operations described herein as being performed by the network node 500. Any information, data and / or signals may be transmitted to a UE, another network node, and / or any other network equipment.

[0218] The power source 508 provides power to the various components of network node 500 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 508 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 500 with power for performing the functionality described herein. For example, the network node 500 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 508. As a further example, the power source 508 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.

[0219] Embodiments of the network node 500 may include additional components beyond those shown in Figure 5 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 subjectmatter described herein. For example, the network node 500 may include user interface equipment to allow input of information into the network node 500 and to allow output of information from the network node 500. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 500.

[0220] Figure 6 is a block diagram illustrating a virtualization environment 600 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 600 hosted by one or more of hardware nodes, such as a hardware computing device that operates as an access network node, UE, core network node, or host. Further, in embodiments in which a 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 600 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.

[0221] Applications 602 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 600 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0222] Hardware 604 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 606 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VM 608 A and VM 608B (which may be collectively referred to as VMs 608), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 606 may present a virtual operating platform that appears like networking hardware to one or more of the VMs 608.The VMs 608 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by virtualization layer 606. Different embodiments of the instance of a virtual appliance 602 may be implemented on one or more of VMs 608, 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.

[0223] In the context of NFV, each of the VMs 608 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 608, and that part of hardware 604 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 of the VMs 608 on top of the hardware 604 and corresponds to an application 602.

[0224] Hardware 604 may be implemented in a standalone network node with generic or specific components. Hardware 604 may implement some functions via virtualization. Alternatively, hardware 604 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 610, which, among others, oversees lifecycle management of applications 602. In some embodiments, hardware 604 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 612 which may alternatively be used for communication between hardware nodes and radio units.

[0225] Although the computing devices described herein (e.g., UEs, network nodes, hosts) 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.

[0226] 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.

[0227] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

[0228] REFERENCES

[0229] 1. R2-2500462 Detection of consecutive HARQ feedback failures in NB-IoT NTN, Google, 2025-02-07

Claims

ClaimsWhat is claimed is:

1. A method performed by a User Equipment device, UE, (212), the method comprising: determining (102) that a retransmission count for a first Radio Link Control, RLC, entity of a first bearer of a group of bearers has exceeded a threshold;determining (104) that a retransmission count for a second RLC entity of a second bearer associated with the group of bearers has not exceeded a threshold; andincreasing (106) a priority level of the first bearer.

2. The method of claim 1, wherein the method is performed for facilitating triggering of a Radio Link Failure, RLF, for an RLC entity.

3. The method of claim 1 or 2, wherein the group of bearers share a Medium Access Control, MAC, entity.

4. The method of any of claims 1 to 3, further comprising:enabling (108) RLC status reports associated with the group of bearers to bypass logical channel prioritization.

5. The method of any of claims 1 to 4, wherein the priority level of the first bearer is reset subsequent to receiving an acknowledgement after transmission of data associated with the retransmission count for the first RLC entity exceeding a threshold.

6. The method of any of claims 1 to 5, further comprising:declaring (110) an RLF when retransmission counts for RLC entities of all bearers of the group of bearers exceed the threshold.

7. The method of any of claims 1 to 6, wherein the increasing the priority level of the first bearer comprises increasing a retransmission count threshold for the first bearer if the second bearer has a higher priority.

8. The method of any of claims 1 to 7, wherein in response to the first RLC entity receiving a status report and there are other RLC entities in the UE (212) that have running t-pollRe transmit, the UE restarts t-pollRetransmit for the other RLC entities.

9. The method of any of claims 1 to 8, wherein in response to the first RLC entity receiving a status report, the UE resets retransmission counts to zero for all RLC Service Data Units, SDUs, or all RLC SDU segments considered for retransmission of other RLC entities.

10. The method of claims 8 to 9, wherein the other RLC entities comprise other RLC entities that belong to the same cell group as the RLC entity receiving the status report.

11. The method of any of claims 1 to 10, wherein the UE (212) comprises a single retransmission counter that is incremented whenever a t-pollRetransmit expires for any Protocol Data Unit.

12. The method of any of claims 1 to 11, further comprising:detecting (110) an RLF when a maximum number of consecutive Hybrid Automatic Repeat Request, HARQ, failures is exceeded.

13. The method of any of claims 1 to 11, further comprising:detecting (110) an RLF in response to a number of downlink transmission decoding errors exceeds a threshold.

14. The method of any of claims 1 to 11, further comprising:detecting (110) an RLF when a beam recovery procedure fails for at least one of:one time,a plurality of times; ora number of times exceeding a threshold.

15. The method of any of claims 1 to 14, wherein an RLF is defined per logical channel or perMedium Access Control entity.

16. The method of any of claims 1 to 15, further comprising:triggering an RLF when a number of t-Reassembly expiries in RLC Unacknowledged Mode, UM, within a time period is above a threshold.

17. The method of any of claims 1 to 16, further comprising:triggering an RLF when a ratio of a number of missing packets to a sum of the number of missing packets and a number of received packets during a time interval is above a threshold.

18. A user equipment device, UE, (212) comprising processing circuitry (402) configured to cause the UE (212) to:determine (102) that a retransmission count for a first Radio Link Control, RLC, entity of a first bearer of a group of bearers has exceeded a threshold;determine (104) that a retransmission count for a second RLC entity of a second bearer associated with the group of bearers has not exceeded a threshold; andincrease (106) a priority level of the first bearer.

19. The UE (212) of claim 18, wherein the processing circuitry (402) is further configured to cause the UE (212) to perform any of claims 2 to 17.

20. A computer program (414) comprising instructions which, when executed by at least one processor (402), cause the at least one processor (402) to carry out the method of any of claims 1 to 17.

21. A carrier (410) containing the computer program (414) of claim 20, wherein the carrier (410) is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

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