Enhancements in monitoring of pc5-to-radio resource control (RRC) configuration procedure in new radio (NR) sidelink (SL)

Abstract

Systems, methods, apparatuses, and computer program products for monitoring a PC5 interface to radio resource control (PC5-RRC) configuration procedure (e.g., in new radio (NR) sidelink (SL) mode 1) are provided. One method can include configuring behavior for a SL user equipment (UE) for handling and monitoring a PC5-RRC procedure and one or more related timers, with consideration of a status of an interface between the SL UE and a network node.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 007450, filed April 9, 2020. The entire contents of this previously filed application are incorporated herein by reference. Technical Field

[0003] Some example embodiments may generally relate to mobile or wireless telecommunication systems, such as Long Term Evolution (LTE) or 5G radio access technologies or New Radio (NR) access technologies, or may relate to other communication systems. For example, some embodiments may relate to systems and / or methods for monitoring the PC5-Radio Resource Control (RRC) configuration process in New Radio (NR) sidechain (SL) mode 1. Background Technology

[0004] Examples of mobile or wireless telecommunications systems can include Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), Evolved UTRAN (E-UTRAN) for Long Term Evolution (LTE), LTE-A Advanced, MulteFire, LTE-A Pro, and / or 5G or New Radio (NR) access technologies. 5G wireless systems refer to next-generation (NG) radio systems and network architectures. 5G systems are primarily built on 5G New Radio (NR), but 5G (or NG) networks can also be built on E-UTRA radio. NR is estimated to offer bit rates of 10-20 Gbit / s or higher and can support at least service categories such as enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC). NR promises to provide ultra-wideband and ultra-robust low-latency connectivity and massive networks to support the Internet of Things (IoT). As IoT and machine-to-machine (M2M) communications become increasingly prevalent, the need for networks capable of meeting the demands of low power consumption, low data rates, and long battery life will continue to grow. Next-Generation Radio Access Network (NG-RAN) refers to the RAN of 5G, which can provide both NR and LTE (and Advanced LTE) radio access. Note that in 5G, nodes that can provide radio access to user equipment (i.e., similar to NodeBs and NBs in UTRAN or evolved NBs and eNBs in LTE) can be named Next-Generation NBs (gNBs) when built on NR radios, and Next-Generation eNBs (NG-eNBs) when built on E-UTRA radios. Summary of the Invention

[0005] The first embodiment relates to a method that can be performed by a network node. The method may include configuring behavior for the SL UE to handle and monitor PC5-RRC procedures and associated timers, taking into account the state of the interface (e.g., Uu link) between the SL UE and the network node.

[0006] For example, in one variant, the configuration may include configuring SL UE to handle a timer used to monitor the PC5 RRC (re)configuration process.

[0007] In one variant, the timer may be a T400 timer. According to one variant, the configuration may include multiple values ​​for configuring the timer for the SLUE or multiple different timers associated with the same PC5-RRC procedure. According to some variants, these multiple values ​​or timers may be used based on the conditions experienced from the interface if there is a physical layer problem, connection re-establishment procedure, or handover procedure via the interface between the SLUE and the network node. In one variant, the interface may be a Uu interface.

[0008] In some variations, a value or timer can be used when a physical layer problem via the interface is not detected and the connection re-establishment and / or handover process is not initiated. In some variations, another value and / or timer can be configured for use, for example, when a physical layer problem is detected. In some variations, another value and / or timer can be configured for use, for example, when a connection re-establishment is initiated. In some variations, another value and / or timer can be configured for use, for example, when the SL UE uses the abnormal resource pool to transmit RRC reconfiguration sidechain messages.

[0009] In one variant, the configuration may include configuring the SL UE to perform the following action: when an RRC reconfiguration sidechain message has been sent to the lower layer and a timer has started, if a physical layer problem is detected or a connection re-establishment or handover process is initiated, the timer (e.g., a T400 timer) is extended. According to some variants, the configuration may include configuring an extended value for the SL UE corresponding to conditions such as experiencing a physical layer problem, performing a connection re-establishment or handover process, or using an abnormal resource pool. In one variant, the timer extension may be associated with a timer configured to monitor a physical layer recovery process, connection re-establishment process, or handover process.

[0010] The second embodiment may involve a method that can be performed by an SL UE (such as an SL TX UE). This method may include determining whether a radio problem exists on the interface between the SL TX UE and a network node. When it is determined that there is no radio problem on the interface, the method may include generating or constructing an RRC reconfiguration sidechain message.

[0011] In one variant, determining whether a radio problem exists may include determining whether there is a physical layer problem, connection re-establishment process, or handover process via the interface between the SL UE and the network. Furthermore, in one variant, when it is determined that there is no physical layer problem, connection re-establishment process, or handover process via the interface, the method may include transmitting an RRC reconfiguration sidechain message to the lower layer and starting timer T400.

[0012] In one variant, determining whether a radio problem exists may include determining at least one of the following: whether (multiple) abnormal resource pools are configured; and / or whether the UE has received a configured authorized type resource before the radio problem is detected.

[0013] According to one variant, the construction of the RRC reconfiguration sidechain message can be performed at the RRC layer of the SL UE. In the example variant, the interface between the SL UE and the network can be the Uu interface.

[0014] In one variant, the transport may include the RRC layer at the SL UE sending an RRC reconfiguration sidechain message to the lower layer only if there is no physical layer problem, connection re-establishment process, or handover process via the Uu interface.

[0015] According to one variant, when a physical layer problem, connection re-establishment process, or handover process is determined to exist via an interface, the method may include not generating or constructing an RRC reconfiguration sidechain message and not starting a timer for monitoring the PC5 RRC (re)configuration process. In one variant, the timer may be a T400 timer. In other words, in one variant, if a physical layer problem, connection re-establishment process, or handover process exists via an interface (e.g., a Uu interface), the RRC layer at the SLUE does not generate or construct an RRC reconfiguration sidechain message, and the timer is not started.

[0016] In one variant, the determination may include checking a timer configured to monitor physical layer (e.g., Uu physical layer) recovery and / or connection re-establishment and / or handover processes. For example, in some variants, the check may include checking whether the T310 timer is running, indicating that the SL UE has detected an N310 continuous desynchronization indication from the lower layer regarding the Uu interface. In one variant, when a physical layer problem is determined to exist, the construction may include constructing an RRC reconfiguration sidechain message after the physical layer problem is resolved (e.g., when the T310 timer stops).

[0017] In another variant, when it is determined that a connection re-establishment or handover process is occurring via an interface, the construct may include constructing an RRC reconfiguration sidechain message after a connection re-establishment or handover to the target cell.

[0018] The third embodiment relates to a method that can be performed by an SL UE. The method may include generating or constructing an RRC reconfiguration sidechain message and starting a timer for monitoring the PC5 RRC (re)configuration process. The method may include, after constructing the RRC reconfiguration sidechain message and starting the timer, detecting a radio problem on the interface between the SL UE and the network node. The method may then include maintaining the timer's value until the radio problem on the interface is resolved.

[0019] In one variant, detecting radio problems on the interface can include detecting physical layer problems via the Uu interface or initiating a connection re-establishment or switching process.

[0020] In another variant, when a physical layer problem is detected or a connection re-establishment or handover process is initiated after constructing the RRC reconfiguration sidechain message and starting a timer (e.g., a T400 timer), the method may include maintaining the timer's value until the physical layer problem is resolved, the connection re-establishment or handover process is completed, or the SL UE enters RRC idle mode. In this variant, once the physical layer problem is resolved or connection re-establishment is performed within the same serving cell, the method may include restarting the timer (e.g., a T400 timer) with the existing value.

[0021] In some variations, when a connection re-establishment or handover process is initiated, the method may include placing a timer (e.g., the T400 timer) into a waiting state. Upon successful connection re-establishment or handover with the new serving cell, or when the SL UE enters RRC idle mode without a successful connection re-establishment or handover, the method may include checking whether the PC5 configuration (in the case of successful connection re-establishment and handover) or SIB / pre-configuration (in the case of entering idle mode) obtained from the new serving cell conforms to the configuration in the constructed RRC reconfiguration sidechain message. If it conforms, the method may include restarting the timer (e.g., the T400 timer) with the existing value. In the case of entering idle mode and switching to SL mode 2, the method may include starting the timer (e.g., the T400 timer) with the existing value once the sensing results are available for use with SL mode 2 at the SL UE. If it does not conform, the method may include constructing a new RRC reconfiguration sidechain message accordingly and restarting the timer with the original / initial value (e.g., the T400 value will be reset and the T400 will restart).

[0022] In one variant, if the connection re-establishment or handover process fails, the method may include switching to SL mode 2. In this variant, the method may include checking whether the configuration obtained from the SIB / pre-configuration matches the configuration in the constructed RRC reconfiguration sidechain message. If it matches, the method may include starting a timer (e.g., a T400 timer). The method may also include starting a timer (e.g., a T400 timer) with existing values ​​once the sensing results are available for using SL mode 2. If it does not match, the method may include constructing a new RRC reconfiguration sidechain message accordingly and starting a timer (e.g., a T400 timer). The method may also include starting a timer (e.g., a T400 timer) once the sensing results are available for using SL mode 2. Furthermore, in this variant, the method may include restarting a timer (e.g., a T400 timer) with the original / initial values ​​when a new RRC reconfiguration sidechain message is transmitted to the lower layer.

[0023] In some variations, the SL UE may be configured by the network with multiple values ​​for a timer (e.g., a T400 timer) or multiple different timers associated with the same PC5-RRC procedure. According to some examples, these different values ​​or timers may be used based on conditions experienced from the interface between the SL UE and the network (e.g., the Uu interface), such as in the presence of physical layer problems, connection re-establishment procedures, or handover procedures via the (Uu) interface.

[0024] In another variant, the SL UE can be configured by the network to extend the timer (e.g., the T400 timer) if a physical layer problem is detected or a connection re-establishment or handover process is initiated, when an RRC reconfiguration sidechain message has been sent to the lower layer and a timer (e.g., the T400 timer) has started. According to some examples, the SL UE can be configured with extended values ​​corresponding to conditions such as experiencing a physical layer problem, performing a connection re-establishment or handover process, or using an abnormal resource pool. In one variant, the timer extension can be associated with a timer configured to monitor the physical layer recovery process, connection re-establishment process, or handover process accordingly.

[0025] The fourth embodiment relates to an apparatus including at least one processor and at least one memory containing computer program code. The at least one memory and the computer program code may be configured, together with the at least one processor, to cause the apparatus to perform at least the methods according to the first embodiment, the second embodiment, the third embodiment, and / or any other embodiment discussed herein or any variations thereof.

[0026] The fifth embodiment relates to an apparatus that may include a circuit system configured to perform methods according to the first, second, third, and / or any other embodiment or any variation thereof discussed herein.

[0027] The sixth embodiment relates to an apparatus that may include components for performing methods according to the first, second, third, and / or any other embodiments discussed herein or any variations thereof.

[0028] The seventh embodiment relates to a non-transitory computer-readable medium including program instructions stored thereon for performing at least the methods according to the first embodiment, the second embodiment, the third embodiment, and / or any other embodiment discussed herein or any variations thereof. Attached Figure Description

[0029] To correctly understand the exemplary embodiments, reference should be made to the accompanying drawings, in which:

[0030] Figure 1 An example signaling diagram according to one embodiment is shown, which depicts an example operation of transmitting a Radio Resource Control (RRC) Reconfiguration Sidelink message using SL Mode 1;

[0031] Figure 2 A diagram is shown depicting an example of a physical layer problem experienced by a UE, according to one embodiment;

[0032] Figure 3 A diagram is shown depicting an example, according to one embodiment, in which a radio problem is resolved by re-establishing an RRC connection with a new cell;

[0033] Figure 4 A diagram is shown depicting an example of an SL transmission (TX) UE entering the RRC-IDLE state and switching to SL mode 2 according to one embodiment;

[0034] Figure 5a An example flowchart of a method according to an example embodiment is shown;

[0035] Figure 5b An example flowchart of a method according to an example embodiment is shown;

[0036] Figure 5c An example flowchart of a method according to an example embodiment is shown;

[0037] Figure 6a An example block diagram of an apparatus according to an example embodiment is shown;

[0038] Figure 6b An example block diagram of a device according to one embodiment is shown; and

[0039] Figure 6c An example block diagram of an apparatus according to an example embodiment is shown. Detailed Implementation

[0040] It will be readily understood that components of certain example embodiments, as generally described and illustrated in the accompanying drawings, can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of some example embodiments of systems, methods, apparatus, and computer program products for monitoring the PC5 interface to RRC (PC5-RRC) configuration process in NR SL mode 1 is not intended to limit the scope of any particular embodiment, but rather represents selected example embodiments.

[0041] Features, structures, or characteristics of the exemplary embodiments described throughout this specification may be combined in any suitable manner in one or more exemplary embodiments. For example, the use of the phrases "some embodiments," "some examples," or other similar language throughout this specification means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment. Therefore, the appearance of the phrases "some embodiments," "some examples," "other examples," or other similar language throughout this specification does not necessarily refer to the same set of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more exemplary embodiments.

[0042] Furthermore, if necessary, the different functions or processes discussed below may be performed in different orders and / or simultaneously with each other. Additionally, if necessary, one or more of the described functions or processes may be optional or may be combined. Therefore, the following description should be considered as illustrating the principles and teachings of certain example embodiments, and not as limiting them.

[0043] Some implementations may involve the 3rd Generation Partnership Project (3GPP) NR sidechain (SL) in version 16 and later. For example, the goal of the NR SL is to provide high reliability and low latency communication (HRLLC) to support advanced vehicle-to-everything (V2X) use cases.

[0044] The goal of NR V2X is to provide advanced V2X services, while the goal of LTE V2X is to provide basic V2X services. In 3GPP Release 16 NR SL specifications (e.g., 3GPP TS 38.331), it has been stated that actions related to the transmission of the sidelink RRC reconfiguration (RRCReconfigurationSidelink) message include the UE setting the content of the RRCReconfigurationSidelink message, as described below.

[0045] For each SL data radio bearer (DRB) to be released, for example, due to sl-ConfigDedicatedNR, System Notification Block Type X (SIBX), SidelinkPreconfigNR, or upper-layer configuration: the UE can set the slrb-PC5-Configlindex included in the slrb-ConfigToReleaseList corresponding to the SL DRB. For each SL DRB to be established or modified, for example, due to received sl-ConfigDedicatedNR, SIBX, SidelinkPreconfigNR: the UE can set the SLRB-Config included in the slrb-ConfigToAddModList according to the received sl-RadioBearerConfig and sl-RLC-BearerConfig corresponding to the SL DRB. For each NR SL measurement and report to be configured, the UE can set the sl-MeasConfig according to the stored NR SL measurement configuration information. The UE can submit an RRCReconfigurationSidelink message to the lower layer for transmission and start timer T400, which is used to monitor the performance of the PC5 RRC (re)configuration process.

[0046] Therefore, the steps described above indicate that timer T400 is activated to detect any issues that occur during the PC5 (re)configuration process when the PC5-RRC needs to be configured or reconfigured. The value of T400 can be defined by the network in the information element of SL-ConfigDedicatedNR, SIBX, or SidelinkPreconfigNR (e.g., t400-r16ENUMERATED{ms100,ms200,ms300,ms400,ms600,ms1000,ms1500,ms2000}).

[0047] When T400 expires and no feedback is received regarding the RRCReconfigurationSidelink message (i.e., RRCReconfigurationCompleteSideLink or RRCReconfigurationFailureSideLink message), the PC5-RRC connection will be handled by the Radio Link Failure (RLF) procedure. Therefore, upon T400 expiration, the TX UE detects a PC5-RRC RLF and performs the same operation as an RLF. This means the TX UE will release the PC5 link and delete its associated configuration.

[0048] Table 1 below lists some timers in the Uu and PC5 interfaces that are related to the relevant RRC procedures.

[0049]

[0050]

[0051] Table 1

[0052] Figure 1 An example signaling diagram is shown, depicting an example operation of transmitting an RRCReconfigurationSidelink message using SL mode 1 (i.e., in mode 1, the initiating UE needs to request SL transmission resources from its serving network). Figure 1 As shown in the example, compared to the Uu interface, the NR SL in Mode 1 requests SL resources from the network to transmit the RRCReconfigurationSidelink message. Note that in this disclosure, this time period can be represented as t_SL_grant. Figure 1 As shown in the example, t_SL_grant can be the time required for an SL connection to acquire resources in the system.

[0053] In SL mode 1, t_SL_grant can depend on the radio conditions of the Uu link and congestion on the Uu interface. For example, after the RRCReconfigurationSidelink message is constructed, it can be provided to the lower layer for transmission, and timer T400 can be started. The UE may then request SL resources, for example, using a buffer status report, scheduling request, or random access procedure. However, if there is a radio link problem on the Uu interface and no abnormal resource pool, the UE may need to resolve the Uu radio link problem first (e.g., perform an RRC re-establishment procedure) before obtaining SL resources from the network. Therefore, if the Uu radio link problem is not resolved before T400 expires, the UE may not be able to transmit the RRCReconfigurationSidelink message before T400 expires; and if the radio link problem is resolved before T400 expires, the remaining time before its expiration may not be sufficient to perform the SL RRC reconfiguration procedure. As used herein, for example, a radio link problem can refer to a problem, condition, or state via the Uu interface that prevents the UE from requesting SL resources from the network, such as experiencing physical layer problems, performing connection re-establishment procedures, and / or handover procedures.

[0054] If multiple configured anomalous resource pools exist, the UE can use these pools to transmit RRCReconfigurationSidelink messages when experiencing a problem where the UE requests sidelink resources from the network under Block Mode 1 from the Uu. However, since the UE needs to randomly select resources from these pools, good sidelink performance cannot be guaranteed. Therefore, in this case, timer T400 may expire due to poor performance when using the multiple anomalous resource pools. Since the multiple anomalous resource pools are only used temporarily, and the UE will later switch back to normal operation, for example, requesting resources from the network or even switching to sense-based resource selection under Mode 2, it is unreasonable to determine sidelink performance by monitoring their temporary performance during the use of the anomalous resource pools.

[0055] After T400 expires, the TX-UE can treat it as a PC5-RRC RLF and release the PC5 radio link. In this case, V2X service between the two SL UEs cannot be supported via PC5, not because of a PC5 radio link problem, but because of a Uu interface radio link problem. This can be recovered by, for example, resolving the physical layer problem, re-establishing the RRC connection in a new serving cell, switching to the target cell, or eventually the UE entering RRC idle mode (e.g., due to the expiration of T301, T310, or T311). In this case, PC5 connection and communication can actually continue. Therefore, it may be necessary to avoid PC5-RRC RLF triggered by T400 expiration due to Uu radio link problems as much as possible.

[0056] Note that the reasons for using the T400 timer may include timely detection of PC5 connectivity issues. In current 3GPP V2X discussions, the discrepancy between the generation of the RRCReconfigurationSidelink message at the TX-UE and its actual transmission to the peer UE, and the corresponding discrepancy of the T400 timer, remains unresolved. However, setting the T400 timer to a large value will prevent timely detection of PC5 connectivity issues and could impact the system in several ways. For example, considering the worst-case scenario for the Uu interface configured with T400 (which is also difficult to predict), the Tx UE might wait for a much longer time than required to perform RLF / RLM. The T400 timer was introduced to monitor SL performance, not for monitoring the Uu link, which will be handled by other timers / procedures. Setting T400 too large could produce the same effect as not using a timer at all. Therefore, the purpose of introducing the T400 timer would be lost. Furthermore, setting the T400 timer to its maximum value (e.g., 2 seconds) does not solve the aforementioned problems. On the other hand, a large T400 value will delay the detection of problems via the PC5 link.

[0057] Some example implementations may involve addressing at least the difficulties of setting timers(s) to monitor the SLRRC configuration process under NR SL Mode 1. For example, one or more implementations may provide new UE behavior regarding handling the PC5 RRC process and related timers by taking into account Uu link status / problems.

[0058] In one embodiment, when there are no radio problems via the Uu interface (e.g., no physical layer problem detected, and / or no connection re-establishment or handover procedure executed), the RRC layer at the sidechain TX-UE (e.g., the initiating TX-UE) can construct an RRCReconfigurationSidelink message and send it to the lower layer, which prevents the UE from requesting SL resources from the network. For example, in one embodiment, the RRC layer at the TX-UE can construct an RRCReconfigurationSidelink message and send it to the lower layer only when there are no physical layer problems or connection re-establishment or handover procedures via the Uu interface. Otherwise, in one embodiment, the RRC layer at the TX-UE should not submit an RRCReconfigurationSidelink message to the lower layer, and therefore, in this case, timer T400 should not be started. Thus, in this case, the SL reconfiguration failure cannot be detected due to the Uu interface problem. The PC5 RRC (re)configuration procedure will be initiated when the physical layer problem of the Uu interface is resolved, or the connection re-establishment or handover procedure via the Uu interface is executed, or the Tx UE enters RRC idle mode.

[0059] For example, the TX-UE can check if its timer T310 is running, indicating that the TX-UE has detected a continuous N310 desynchronization indication from the lower layer regarding the Uu interface. Therefore, if T400 starts without noticing that timer T310 is running, T400 may expire before the physical layer problem is resolved, leading to the release of the PC5 link, which is unreasonable as it does not reflect the state of the PC5 link. In this case, the TX-UE should construct the RRCReconfigurationSidelink message after the physical layer problem is resolved (e.g., when T310 stops).

[0060] The same principle applies if the TX-UE is attempting a Uu connection re-establishment process, for example, when T301 or T311 is running. In this case, the TX-UE cannot obtain SL resources from the network before the Uu connection is re-established. Therefore, T400 should not be initiated in this situation to avoid it expiring before the Uu connection is established, as this would release the PC5 link. Furthermore, if the UE re-establishes a Uu connection to a new cell, it can obtain the new PC5 configuration from the new cell. Therefore, it is reasonable to wait and construct the RRCReconfigurationSidelink message after the Uu connection is re-established.

[0061] In another example, after receiving an RRCReconfiguration message including reconfigurationWithSync, the UE will start its timer T304 and perform a handover to the corresponding special cell (SpCell). Therefore, the UE cannot request sidelink resources from the network before the handover process is successful. Similarly, since the UE can obtain the new PC5 configuration from the target cell, it is reasonable to wait and construct an RRCReconfigurationSidelink message after the handover process.

[0062] In another embodiment, if the TX-UE detects a Uu physical layer problem or initiates a Uu connection re-establishment or handover process after constructing the RRCReconfigurationSidelink message and starting T400, the TX-UE can maintain the value of timer T400 until the Uu physical layer problem is resolved, the Uu connection re-establishment or handover process is completed, or the UE enters RRC idle mode. For example, when the TX-UE detects a physical layer problem (e.g., timer T310 starts or the radio channel condition is worse than the configured threshold), timer T400 will be placed in a waiting state (in other words, T400 will stop, but will not be reset to its initial value). Once the Uu physical layer problem is resolved in the same serving cell (e.g., T310 stops or the radio channel condition is better than the configured threshold), T400 can continue to operate.

[0063] If the TX-UE initiates a Uu connection re-establishment process (e.g., due to the maximum number of retransmissions via the Uu interface being reached, or a handover failure causing RLC failure) or initiates a handover process, timer T400 should also be placed in a waiting state. After a successful Uu re-establishment with the same serving cell, T400 can continue operating. After a successful Uu re-establishment or handover with a new serving cell, or when the UE enters RRC idle mode due to a failed Uu re-establishment or handover failure, the TX-UE can check whether the PC5 configuration obtained from the new serving cell (in the case of a successful Uu re-establishment) or SIB / pre-configuration (in the case of entering idle mode) matches the configuration in the constructed RRCReconfigurationSidelink message. If it matches, timer T400 can continue operating. In the case of the UE entering idle mode and switching to SL mode 2, T400 will continue operating once the sensing results at the TX-UE are available for using SL mode 2. If the condition is not met, the UE can construct a new RRCReconfigurationSidelink message and restart timer T400 once the sensing result is available for use with SL mode 2 (i.e., the value of T400 will be reset to 0 and T400 will restart). For example, in this case, the UE can construct a new RRCReconfigurationSidelink message and restart timer T400 when the new RRCReconfigurationSidelink message is transmitted.

[0064] In one example, if the Uu connection re-establishment or handover process fails, the UE can switch to SL mode 2 (i.e., UE autonomous resource selection mode). In this case, the TX-UE can check whether the configuration obtained from the SIB / pre-configuration matches the configuration in the constructed RRCReconfigurationSidelink message. If it matches, timer T400 can continue running once the sensing results are available at the UE for using SL mode 2. If it does not match, the TX-UE can construct a new RRCReconfigurationSidelink message accordingly once the sensing results are available for using SL mode 2. Furthermore, the UE can restart timer T400 when the new RRCReconfigurationSidelink message is transmitted to the lower layer.

[0065] Figure 2 An example of an embodiment in which the UE experiences physical layer problems is shown. Figure 2In the example, after the RRC transmits the RRCReconfigurationSidelink message to the lower layer, T400 begins at t0. At t1, the SL TX-UE experiences a physical layer problem (e.g., T310 begins). Therefore, the SL TX-UE will remain in T400, e.g., T400 = T1. At a later point in time, e.g., t2, the radio problem is resolved (e.g., T310 stops), and the SL TX-UE is able to communicate with the same serving cell as before. Therefore, the SL TX-UE will no longer remain in T400 and will continue operating from T400 = T1. At t3, the SL TX-UE will receive a feedback message from the peer UE. Therefore, in this example embodiment, T400 will operate for the duration of T1 and T2, but is not used to monitor the process where the Uu link problem occurs (i.e., between t1 and t2), which will be handled by other timers (e.g., T310). The PC5 RRC (re)configuration process is considered successful as long as T1+T2 is less than the configured value of timer T400, and it prevents the UE from declaring an RLF and releasing the PC5 connection due to the Uu problem.

[0066] Figure 3 An example of an embodiment is shown, in which radio problems are resolved by re-establishing the RRC connection or switching to a new cell. For example... Figure 3 As shown in the example, at t2, the SL TX-UE has re-established its RRC connection or switched to a new cell. In this case, at t3, the SL TX-UE will check whether the new configuration from the new cell matches the RRCReconfigurationSidelink message generated at t0. If it does not match, then... Figure 3 As shown in the example, it needs to generate a new RRCReconfigurationSideLink message at t4 based on the new configuration obtained from the new cell. Furthermore, timer T400 will start from its initial value. In this case, the PC5 RRC (re)configuration process is considered successful as long as T2 is less than the configured value of timer T400, and it prevents the UE from declaring an RLF and releasing the PC5 connection due to a Uu problem. If the new cell's configuration matches the RRCReconfigurationSideLink message generated at t0, the timer can continue from T400 = T1 (note that...). Figure 3 (This situation is not shown in the example).

[0067] Figure 4 An example embodiment is shown where the SL TX-UE enters the RRC-IDLE state (e.g., due to the expiration of T301, T310, or T311) and switches to SL mode 2. Figure 4As shown in the example, the UE can read the SIB / pre-configuration at t3 to check if the RRCReconfigurationSidelink message generated at t0 matches the configuration obtained from the new state. If it does not match, then... Figure 4 As shown in the example, once the sensing results are available, for example at t4, the UE can generate a new RRCReconfigurationSidelink message and start timer T400 from its initial value. In this case, as long as T2 is less than the configured value of timer T400, the PC5 RRC (re)configuration process is considered successful, and it prevents the UE from declaring RLF and releasing the PC5 connection due to Uu issues.

[0068] In another embodiment, the TX-UE can be configured with multiple values ​​for T400 or multiple different classes of T400 timers associated with the same PC5-RRC procedure. For example, different values ​​or timers can be used / configured based on different conditions experienced from the Uu interface if a physical layer problem, connection re-establishment procedure, or handover procedure exists via the Uu. For example, one value and / or timer can be used if no Uu physical layer problem is detected and Uu connection re-establishment and handover are not initiated. Another value and / or timer can be configured for use, for example, when a Uu physical layer problem is detected. In this case, upon detection of such a physical layer problem, an RRC layer update will be used to detect the expiration value of T400 in that particular case. Another value and / or timer can be configured for use, for example, when a Uu connection re-establishment is initiated. Another value and / or timer can be configured for use, for example, when a handover procedure is initiated. Another value and / or timer can be configured for use, for example, when the SL TX-UE uses an abnormal resource pool to transmit RRCReconfigurationSidelink messages. Note that multiple values ​​or different classes of T400 timers can be applied to situations where a radio problem with the Uu is detected before and / or after the RRCReconfigurationSidelink message is submitted to the lower layer. Therefore, in this approach, different values ​​or timers used to monitor the PC5 RRC (re)configuration process can be configured / updated based on different radio conditions of the Uu interface.

[0069] In another embodiment, if the RRCReconfigurationSidelink message has been sent to the lower layer and T400 has been initiated, the TX-UE can be configured to extend timer T400 upon detection of a Uu physical layer problem or the initiation of a Uu re-establishment or handover procedure. According to some examples, the UE can be configured by the network with extended values ​​corresponding to the conditions described above, such as experiencing a Uu physical layer problem, performing a Uu connection re-establishment, performing a handover procedure, or using an abnormal resource pool. In one example, the timer extension can be associated with a timer configured to monitor a Uu physical layer recovery process, a Uu connection re-establishment process, or a handover procedure. For example, if the TX-UE is configured with a constant T0 for T400 and constants T1, T2, and T3 for detecting the expiration of T301, T310, and T311 respectively, then: if the TX-UE detects a physical layer problem that triggers T310, the constant of T400 can be extended to (T0+T2); if the physical layer problem cannot be resolved and T310 expires, the TX-UE can initiate a Uu connection re-establishment procedure, which includes a procedure for selecting a suitable cell and another procedure for requesting RRC re-establishment via the Uu interface. In this case, the constant of T400 can be extended to (T0+T2+T3+T1). In an example embodiment, the TX-UE can also initiate a Uu connection re-establishment procedure due to other triggers (e.g., RLC failure when the maximum number of retransmissions is reached). In this case, the constant of T400 can be extended to (T0+T3+T1). It should be noted that the above examples do not limit the scope of this embodiment, but are only used as examples to more easily help understand this embodiment.

[0070] It should be noted that, according to some embodiments, once the RRCReconfigurationSidelink message is provided from the RRC layer to the lower layer, it is considered to be in transit.

[0071] Figure 5a An example flowchart is shown, illustrating a method related to, for example, monitoring the PC5-RRC configuration process in NR SL mode 1, according to an example embodiment. In some example embodiments, Figure 5a The flowchart can be executed by network entities or network nodes in a communication system, such as LTE or 5G NR. For example, in some example embodiments, the execution... Figure 5a The network nodes for this method may include base stations, eNBs, gNBs, and / or NG-RAN nodes, etc.

[0072] like Figure 5a As shown in the example, the method may include: in 500, configuring the SF UE to handle and monitor the PC5 RRC process and related timers by taking into account the Uu link status / problems.

[0073] In one embodiment, configuration 500 may include configuring the SL UE such that when there is no radio problem via the Uu interface (e.g., no physical layer problem detected, and / or no connection re-establishment or handover procedure performed), the SL UE's RRC layer can construct and send an RRCReconfigurationSidelink message to the lower layer, which prevents the SL UE from requesting SL resources from the network node. For example, in one embodiment, the RRC layer at the SL UE may construct and send an RRCReconfigurationSidelink message to the lower layer only when there is no physical layer problem via the Uu interface or a connection re-establishment or handover procedure. Otherwise, in one embodiment, configuration 500 may include configuring the SL UE such that its RRC layer should not submit an RRCReconfigurationSidelink message to the lower layer, and therefore, in this case, timer T400 should not be started.

[0074] In another embodiment, configuration 500 may include configuring the SL UE such that if the SL UE detects a Uu physical layer problem or initiates a Uu connection re-establishment or handover process after constructing the RRCReconfigurationSidelink message and starting T400, the SL UE is configured to maintain the value of timer T400 until the Uu physical layer problem is resolved, the Uu connection re-establishment or handover process is completed, or the SL UE enters RRC idle mode. For example, when the SL UE detects a physical layer problem (e.g., timer T310 starts or radio channel conditions are worse than a configured threshold), the SL UE is configured to place timer T400 in a waiting state (in other words, T400 will stop, but will not reset to its initial value). Once the Uu physical layer problem is resolved in the same serving cell (e.g., T310 stops or radio channel conditions are better than a configured threshold), the SL UE is configured to restart timer T400 so that it can continue to operate.

[0075] For example, in one embodiment, configuration 500 may include processing of configuring the SL UE for a timer (e.g., a T400 timer) used to determine when to perform an SL reconfiguration failure procedure. In one embodiment, configuration 500 may include configuring multiple values ​​for a timer (e.g., T400) for the SL UE or multiple different similar timers associated with the same PC5-RRC procedure. According to some examples, different values ​​or timers may be used based on conditions experienced from the interface between the SL UE and the network (e.g., the Uu interface) if a physical layer problem or connection re-establishment procedure or handover procedure exists via the (Uu) interface. For example, one value and / or timer may be used if a physical layer problem is not detected and a connection re-establishment is not initiated. Another value and / or timer may be configured to be used, for example, when a physical layer problem is detected. In this case, upon detection of such a physical layer problem, the RRC layer may update a constant that will be used to detect the expiration of the timer (e.g., the T400 timer). Another value and / or timer may be configured to be used, for example, when a connection re-establishment is initiated. Another value and / or timer can be configured, for example, when the SL UE uses the exception resource pool to transmit RRC reconfiguration sidechain messages.

[0076] In one embodiment, configuration 500 may include configuring the SL UE to extend the timer (e.g., the T400 timer) when a physical layer problem or the initiation of a connection re-establishment process is detected, once an RRC reconfiguration sidechain message has been sent to the lower layer and a timer (e.g., a T400 timer) has started. According to some examples, configuration 500 may include configuring an extended value for the SL UE corresponding to the conditions described above, such as experiencing a physical layer problem, performing a connection re-establishment, or using an abnormal resource pool. In one example, the timer extension may be associated with a timer configured to monitor a physical layer recovery process or a connection re-establishment process. For example, if the SL UE is configured with a constant T0 for the T400 timer and constants T1, T2, and T3 for detecting the expiration of timers T301, T310, and T311 respectively, then: if the SL UE detects a physical layer problem that triggers T310 initiation, the constant of T400 can be extended to (T0+T2); if the physical layer problem cannot be resolved and T310 expires, the SL UE can initiate a Uu connection re-establishment procedure, which includes a procedure for selecting a suitable cell and another procedure for requesting RRC re-establishment via the Uu interface. In this case, the constant of the T400 timer can be extended to (T0+T2+T3+T1). In an example embodiment, the method may include configuring the SL UE to initiate a Uu connection re-establishment procedure due to other triggers (e.g., RLC failure when the maximum number of retransmissions is reached). In this case, the constant of the T400 timer can be extended to (T0+T3+T1).

[0077] Figure 5b An example flowchart is shown, illustrating a method for monitoring the PC5-RRC configuration process, for example, in NR SL mode 1, according to an example embodiment. In some example embodiments, Figure 5b The flowchart can be executed by network entities or network nodes in a communication system (such as LTE or 5G NR). For example, in some example embodiments, the execution... Figure 5b The network entities in the method may include UEs, such as SL UEs (e.g., SL TX UEs or SL RX UEs), mobile stations, IoT devices, etc.

[0078] In one embodiment, Figure 5bThe method may include: at 530, determining whether a radio problem exists. For example, determining 530 may include determining whether a physical layer problem, connection re-establishment process, or handover process exists via the interface between the SL UE and the network (e.g., the Uu interface). In one embodiment, when it is determined at 530 that no radio problem exists (e.g., no physical layer problem, no connection re-establishment process via the Uu interface, and / or no handover process is performed), the method may include: at 535, constructing an RRC reconfiguration sidechain message. The method may then include: at 540, transmitting the RRC reconfiguration sidechain message to the lower layer and starting a timer (e.g., timer T400) for monitoring the PC5 RRC (re)configuration process. For example, in one embodiment, transmission 540 may include the RRC layer at the SL UE sending the RRC reconfiguration sidechain message to the lower layer only if there is no physical layer problem, connection re-establishment process, or handover process via the Uu interface. Otherwise, when a radio problem is identified at 530 (e.g., a physical layer problem via the Uu interface or a connection re-establishment or handover process), the method may include: at 550, not constructing an RRC reconfiguration sidechain message and not starting a timer (e.g., timer T400) for monitoring the PC5 RRC (re)configuration process.

[0079] Figure 5c An example flowchart is shown, illustrating a method for monitoring the PC5-RRC configuration process, for example, in NR SL mode 1, according to another example embodiment. In some example embodiments, Figure 5c The flowchart can be executed by network entities or network nodes in a communication system (such as LTE or 5G NR). For example, in some example embodiments, the execution... Figure 5c The network entities in the method may include UEs, such as SL UEs (e.g., SL TX UEs or SL RX UEs), mobile stations, IoT devices, etc.

[0080] In one embodiment, Figure 5cThe method may include, at 560, constructing an RRC reconfiguration sidechain message, submitting it to the lower layer, and starting a timer (e.g., timer T400) for monitoring the PC5 RRC (re)configuration process. According to one embodiment, after constructing the RRC reconfiguration sidechain message, submitting it to the lower layer, and starting the timer, the method may include, at 570, detecting a radio problem (e.g., a physical layer problem via the Uu interface, a connection re-establishment process, or a handover process). In one embodiment, the method may include, at 580, maintaining the value of the timer (e.g., T400) until the radio problem is resolved. For example, the radio problem may be resolved when the physical layer problem is resolved, when a connection re-establishment process within the same serving cell is completed, or when a handover process to a new cell via an interface (e.g., the Uu interface) is completed.

[0081] Therefore, in Figure 5c In one embodiment shown in the example, when a physical layer problem is detected or a connection re-establishment process is initiated after constructing the RRC reconfiguration sidechain message and starting the T400 timer, the method may include holding the value of the timer T400 until the physical layer problem is resolved, the connection re-establishment or handover process is completed, or the UE enters RRC idle mode.

[0082] In one embodiment, detection 570 may include checking whether the T310 timer is running, which indicates that the SL UE has detected an N310 continuous desynchronization indication from the lower layer regarding the Uu interface.

[0083] For example, when a physical layer problem is detected (e.g., timer T310 starts or radio channel conditions are worse than a configured threshold), the method may include placing timer T400 in a waiting state (in other words, timer T400 will stop, but its value will not be reset to its initial value). Once the physical layer problem is resolved in the same serving cell (e.g., T310 stops or radio channel conditions are better than a configured threshold), the method may include restarting timer T400.

[0084] In one embodiment, when a connection re-establishment process is initiated (e.g., due to the maximum number of retransmissions via the Uu interface being reached, or a handover failure causing RLC failure) or a handover process is started, the method may include placing timer T400 in a waiting state. After a successful Uu re-establishment with the same serving cell, T400 may continue operating. After a successful connection re-establishment or handover with a new serving cell, or when the UE enters RRC idle mode without a successful connection re-establishment, the method may include checking whether the PC5 configuration obtained from the new serving cell (in the case of a successful Uu re-establishment) or SIB / pre-configuration (in the case of entering idle mode) conforms to the configuration in the constructed RRC reconfiguration sidechain message. If it does, the method may include restarting timer T400. In the case of entering idle mode and switching to SL mode 2, the method may include starting timer T400 once the sensing results at the SL UE are available for using SL mode 2. If not, the method may include: once the sensing result is available for use with SL mode 2, constructing a new RRC reconfiguration sidelink message accordingly and restarting timer T400 (i.e., the value of T400 is reset to 0 and T400 is restarted again). For example, in this case, the method may include constructing a new RRC reconfiguration sidelink message and restarting timer T400 when a new RRCReconfigurationSidelink message is transmitted.

[0085] In one example, if the connection re-establishment or handover process fails, the method may include switching to SL mode 2 (i.e., UE autonomous resource selection mode). In this case, the method may include checking whether the configuration obtained from the SIB / pre-configuration matches the configuration in the constructed RRC reconfiguration sidechain message. If it matches, the method may include starting timer T400 once the sensing results are available for using SL mode 2. If it does not match, the method may include constructing a new RRC reconfiguration sidechain message accordingly once the sensing results are available for using SL mode 2. Furthermore, the method may include restarting timer T400 when the new RRC reconfiguration sidechain message is transmitted to the lower layer.

[0086] In some embodiments, the SL UE may be configured by the network with multiple values ​​for timers (e.g., the T400 timer) or multiple different similar timers associated with the same PC5-RRC procedure. According to some examples, if a physical layer problem, connection re-establishment procedure, or handover procedure occurs via the (Uu) interface, different values ​​or timers can be used or configured based on different conditions experienced from the interface between the SL UE and the network (e.g., the Uu interface). For example, one value and / or timer may be used if a Uu physical layer problem is not detected and connection re-establishment and handover are not initiated. Another value and / or timer may be configured to be used, for example, when a physical layer problem is detected. In this case, upon detection of such a physical layer problem, the RRC layer may update the expiration value of the detection timer (e.g., the T400 timer). Another value and / or timer may be configured to be used, for example, when connection re-establishment is initiated. Another value and / or timer may be configured to be used, for example, when a handover procedure is initiated. And, another value and / or timer may be configured to be used, for example, when the SL UE uses an abnormal resource pool to transmit RRC reconfiguration sidechain messages. According to the example embodiment, multiple values ​​or multiple different classes of T400 timers can be applied to situations where a radio problem with Uu is detected before and / or after the RRCReconfigurationSidelink message is committed to the lower layer. Therefore, in some embodiments, different values ​​or timers used to monitor the PC5 RRC (re)configuration process can be configured / updated according to different radio conditions of the Uu interface.

[0087] In one embodiment, when an RRC reconfiguration sidechain message has been sent to the lower layer and a timer (e.g., a T400 timer) has started, the SL UE can be configured by the network to extend the timer (e.g., the T400 timer) upon detection of a physical layer problem or the initiation of a connection re-establishment or handover process. According to some examples, the SL UE can be configured with extension values ​​corresponding to the conditions described above, such as experiencing a physical layer problem, performing a connection re-establishment or handover process, or using an abnormal resource pool. In one example, the timer extension can be associated with a timer configured to monitor a physical layer recovery process or a connection re-establishment or handover process.

[0088] It should be noted that, according to certain embodiments, Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5a , Figure 5b or Figure 5c One or more of the processes, functions, or boxes shown may be optional or can be skipped. Therefore, Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5a or Figure 5b Some embodiments have been shown, but it should not be assumed that the embodiments are limited to these examples. Furthermore, in some embodiments, Figure 5a , Figure 5b or Figure 5c The examples shown in the flowchart can be combined or merged.

[0089] Figure 6a An example of apparatus 10 according to one embodiment is shown. In one embodiment, apparatus 10 may be a node, host, or server in or serving a communications network. For example, apparatus 10 may be a satellite, base station, Node B, evolved Node B (eNB), 5G Node B or access point, next-generation Node B (NG-NB or gNB), and / or WLAN access point associated with a radio access network (such as an LTE network, 5G, or NR). In the example embodiment, apparatus 10 may be an NG-RAN node, an eNB in ​​LTE, or a gNB in ​​5G.

[0090] It should be understood that in some example embodiments, device 10 may include an edge cloud server as a distributed computing system, wherein the server and radio nodes may be separate devices communicating with each other via a radio path or via a wired connection, or wherein they may reside in the same entity communicating via a wired connection. For example, in some example embodiments where device 10 represents a gNB, it may be configured in a central unit (CU) and distributed unit (DU) architecture that divides gNB functions. In such an architecture, the CU may be a logical node that includes gNB functions such as user data transmission, mobility control, radio access network sharing, location and / or session management, etc. The CU may control the operation of the DU(s) through a fronthaul interface. The DU may be a logical node that includes a subset of gNB functions, depending on the function splitting options. It should be noted that those skilled in the art will understand that device 10 may include Figure 6a Components or features not shown in the diagram.

[0091] like Figure 6a As shown in the example, device 10 may include a processor 12 for processing information and executing instructions or operations. Processor 12 may be any type of general-purpose or special-purpose processor. In fact, for example, processor 12 may include one or more of the following: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), and processor based on a multi-core processor architecture. Although Figure 6aA single processor 12 is shown, but multiple processors may be used according to other embodiments. For example, it should be understood that in some embodiments, device 10 may include two or more processors that can form a multiprocessor system capable of supporting multiple processing (e.g., in this case, processor 12 may represent multiple processors). In some embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0092] The processor 12 can perform functions associated with the operation of the device 10, which may include, for example, precoding of antenna gain / phase parameters, encoding and decoding of individual bits forming communication messages, formatting of information, and overall control of the device 10, including processes related to the management of communication resources.

[0093] Device 10 may also include or be coupled to memory 14 (internal or external), which may be coupled to processor 12, for storing information and instructions executable by processor 12. Memory 14 may be one or more memories and may be of any type suitable for the local application environment, and may be implemented using any suitable volatile or non-volatile data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and / or removable memory. For example, memory 14 may include random access memory (RAM), read-only memory (ROM), static storage devices such as disks or optical discs, hard disk drives (HDDs), or any combination of any other type of non-transitory machine or computer-readable medium. Instructions stored in memory 14 may include program instructions or computer program code that, when executed by processor 12, enable device 10 to perform the tasks described herein.

[0094] In one embodiment, device 10 may further include or be coupled to an (internal or external) drive or port configured to accept and read external computer-readable storage media, such as an optical disc, USB drive, flash drive, or any other storage media. For example, the external computer-readable storage media may store computer programs or software that are executed by processor 12 and / or device 10.

[0095] In some embodiments, device 10 may further include or be coupled to one or more antennas 15 for transmitting and / or transmitting signals and / or data to and from device 10. Device 10 may also include or be coupled to a transceiver 18 configured to transmit and receive information. Transceiver 18 may include, for example, multiple radio interfaces that may be coupled to antenna(s) 15. The radio interfaces may correspond to a variety of radio access technologies, including one or more of the following: GSM, NB-IoT, LTE, 5G, WLAN, Bluetooth, BT-LE, NFC, RFID, UWB, MulteFire, etc. The radio interfaces may include components such as filters, converters (e.g., digital-to-analog converters), mappers, Fast Fourier Transform (FFT) modules, etc., to generate symbols for transmission via one or more downlinks and to receive symbols (e.g., via an uplink).

[0096] Therefore, transceiver 18 can be configured to modulate information onto a carrier waveform for transmission by antenna(s)15 and demodulate information received via antenna(s)15 for further processing by other elements of device 10. In other embodiments, transceiver 18 may be able to directly transmit and receive signals or data. Additionally or alternatively, in some embodiments, device 10 may include input and / or output devices (I / O devices).

[0097] In one embodiment, memory 14 may store software modules that provide functionality when executed by processor 12. These modules may include, for example, an operating system that provides operating system functionality to device 10. The memory may also store one or more functional modules, such as applications or programs, to provide additional functionality to device 10. Components of device 10 may be implemented in hardware or as any suitable combination of hardware and software.

[0098] According to some embodiments, the processor 12 and memory 14 may be included in or form part of a processing circuitry or control circuitry. Furthermore, in some embodiments, the transceiver 18 may be included in or form part of a transceiver circuitry.

[0099] As used herein, the term "circuit system" can refer to a hardware circuit implementation only (e.g., analog and / or digital circuit systems), a combination of hardware circuits and software, a combination of analog and / or digital hardware circuits with software / firmware, any part of a hardware processor(s) (including digital signal processors) having software working together to cause a device (e.g., device 10) to perform various functions, and / or a hardware circuit and / or processor(s) or a portion thereof that operates using software but may be absent when operation is not required. As another example, as used herein, the term "circuit system" can also encompass a hardware circuit or processor (or multiple processors) only, or a portion of a hardware circuit or processor, and its accompanying software and / or firmware implementation. The term "circuit system" can also encompass baseband integrated circuits, for example, in servers, cellular network nodes or devices, or other computing or networking devices.

[0100] As described above, in some embodiments, device 10 may be an NW node or RAN node, such as a base station, access point, node B, eNB, gNB, WLAN access point, etc. For example, in some embodiments, device 10 may be configured to perform one or more processes depicted in any flowchart or signaling diagram described herein, such as... Figure 1 , Figure 5a or Figure 5b As shown. According to one embodiment, device 10 may correspond to Figure 1 The network block shown in the example. In some embodiments, as described herein, apparatus 10 may be configured to perform processes related to monitoring and improving the PC5-RRC (re)configuration process in NR SL.

[0101] According to some embodiments, the device 10 may be controlled by the memory 14 and the processor 12 to configure the SL UE for processing and monitoring the behavior of the PC5 RRC process and related timers in consideration of the Uu link status / problems.

[0102] In some embodiments, the apparatus 10 may be controlled by the memory 14 and the processor 12 to configure the SL UE such that when there is no radio problem via the Uu interface (e.g., no physical layer problem detected, and / or no connection re-establishment or handover procedure is performed), the RRC layer of the SL UE can construct an RRCReconfigurationSidelink message and send it to the lower layer, which prevents the SL UE from requesting SL resources from the network node. For example, in one embodiment, the apparatus 10 may be controlled by the memory 14 and the processor 12 to configure the RRC layer at the SL UE to construct an RRCReconfigurationSidelink message and send it to the lower layer only when there is no physical layer problem via the Uu interface or a connection re-establishment or handover procedure. Otherwise, in one embodiment, the apparatus 10 may be controlled by the memory 14 and the processor 12 to configure the SL UE such that its RRC layer should not submit an RRCReconfigurationSidelink message to the lower layer, and therefore, in this case, timer T400 should not be started.

[0103] In another embodiment, device 10 may be controlled by memory 14 and processor 12 to configure the SL UE such that if the SL UE detects a Uu physical layer problem or initiates a Uu connection re-establishment or handover process after constructing an RRCReconfigurationSidelink message and initiating T400, the SL UE is configured to maintain the value of timer T400 until the Uu physical layer problem is resolved, the Uu connection re-establishment or handover process is completed, or the SL UE enters RRC idle mode. For example, when the SL UE detects a physical layer problem (e.g., timer T310 starts or radio channel conditions are worse than a configured threshold), device 100 may be controlled by memory 14 and processor 12 to configure the SL UE to place timer T400 in a waiting state (in other words, T400 will stop, but will not be reset to its initial value). Once the Uu physical layer problem is resolved in the same serving cell (e.g., T310 stops or radio channel conditions are better than a configured threshold), the SL UE is configured to restart timer T400 so that it can continue to operate.

[0104] In one embodiment, device 10 may be controlled by memory 14 and processor 12 to configure the SL UE for processing of timers (e.g., the T400 timer) used to determine when to perform an SL reconfiguration failure procedure. In one embodiment, device 10 may be controlled by memory 14 and processor 12 to configure multiple values ​​for timers (e.g., T400) or multiple different similar timers associated with the same PC5-RRC procedure for the SL UE. According to some examples, different values ​​or timers may be used based on conditions experienced from the interface between the SL UE and the network (e.g., the Uu interface) if a physical layer problem or connection re-establishment procedure or handover procedure exists via the (Uu) interface. For example, one value and / or timer may be used if a physical layer problem is not detected and a connection re-establishment is not initiated. Another value and / or timer may be configured to be used, for example, when a physical layer problem is detected. In this case, upon detection of such a physical layer problem, the RRC layer may update a constant that will be used to detect the expiration of the timer (e.g., the T400 timer). Another value and / or timer may be configured to be used, for example, when a connection re-establishment is initiated. Another value and / or timer can be configured, for example, when the SL UE uses the exception resource pool to transmit RRC reconfiguration sidechain messages.

[0105] In one embodiment, device 10 may be controlled by memory 14 and processor 12 to configure the SL UE to extend the timer (e.g., the T400 timer) when a physical layer problem or the initiation of a connection re-establishment process is detected, once an RRC reconfiguration sidechain message has been sent to the lower layer and a timer (e.g., the T400 timer) has started. According to some examples, device 10 may be controlled by memory 14 and processor 12 to configure the SL UE with an extended value corresponding to the conditions described above, such as experiencing a physical layer problem, performing a connection re-establishment, or using an abnormal resource pool. In one example, the timer extension may be associated with a timer configured to monitor the physical layer recovery process or the connection re-establishment process. For example, if the SLUE is configured with a constant T0 for the T400 timer and constants T1, T2, and T3 for detecting the expiration of the T301, T310, and T311 timers respectively, then: if the SLUE detects a physical layer problem that triggers T310, the constant of T400 can be extended to (T0+T2); if the physical layer problem cannot be resolved and T310 expires, the SLUE can initiate a Uu connection re-establishment procedure, which includes a procedure for selecting a suitable cell and another procedure for requesting RRC re-establishment via the Uu interface. In this case, the constant of the T400 timer can be extended to (T0+T2+T3+T1). In an example embodiment, the apparatus 10 can be controlled by the memory 14 and the processor 12 to configure the SLUE to initiate a Uu connection re-establishment procedure due to other triggers (e.g., RLC failure when the maximum number of retransmissions is reached). In this case, the constant of the T400 timer can be extended to (T0+T3+T1).

[0106] Figure 6b An example of apparatus 20 according to another embodiment is shown. In one embodiment, apparatus 20 may be a node or element in or associated with a communication network, such as a UE, mobile device (ME), mobile station, mobile device, fixed device, IoT device, or other device. As described herein, UE may alternatively be referred to as, for example, mobile station, mobile equipment, mobile unit, mobile device, user equipment, subscriber station, wireless terminal, tablet computer, smartphone, IoT device, sensor, or NB-IoT device, etc. As an example, apparatus 20 may be implemented in, for example, a wireless handheld device, a wireless plug-in accessory, etc.

[0107] In some example embodiments, device 20 may include one or more processors, one or more computer-readable storage media (e.g., memory, storage device, etc.), one or more radio access components (e.g., modem, transceiver, etc.), and / or a user interface. In some embodiments, device 20 may be configured to operate using one or more radio access technologies, such as GSM, LTE, LTE-A, NR, 5G, WLAN, WiFi, NB-IoT, Bluetooth, NFC, MulteFire, and / or any other radio access technology. It should be noted that those skilled in the art will understand that device 20 may include... Figure 6b Components or features not shown in the diagram.

[0108] like Figure 6b As shown in the example, device 20 may include or be coupled to a processor 22 for processing information and executing instructions or operations. Processor 22 may be any type of general-purpose or special-purpose processor. In fact, processor 22 may be any of the following types: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), and processor based on a multi-core processor architecture. Although Figure 6b A single processor 22 is shown, but multiple processors may be used according to other embodiments. For example, it should be understood that in some embodiments, device 20 may include two or more processors, which may form a multiprocessor system capable of supporting multiple processing (e.g., in this case, processor 22 may represent multiple processors). In some embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0109] The processor 22 can perform functions associated with the operation of the device 20, including, for example, precoding of antenna gain / phase parameters, encoding and decoding of individual bits forming communication messages, formatting of information, and overall control of the device 20, including processes related to the management of communication resources.

[0110] Device 20 may also include or be coupled to memory 24 (internal or external), which may be coupled to processor 22 for storing information and instructions executable by processor 22. Memory 24 may be one or more memories of any type suitable for the local application environment and may be implemented using any suitable volatile or non-volatile data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and / or removable memory. For example, memory 24 may include random access memory (RAM), read-only memory (ROM), static storage devices such as disks or optical discs, hard disk drives (HDDs), or any other type of non-transitory machine or computer-readable medium and any combination thereof. Instructions stored in memory 24 may include program instructions or computer program code that, when executed by processor 22, enable device 20 to perform the tasks described herein.

[0111] In one embodiment, device 20 may further include or be coupled to an (internal or external) drive or port configured to accept and read external computer-readable storage media, such as an optical disc, USB drive, flash drive, or any other storage media. For example, the external computer-readable storage media may store computer programs or software that are executed by processor 22 and / or device 20.

[0112] In some embodiments, device 20 may further include or be coupled to one or more antennas 25 for receiving downlink signals and / or for transmission from device 20 via an uplink. Device 20 may also include a transceiver 28 configured to transmit and receive information. Transceiver 28 may also include a radio interface (e.g., a modem) coupled to antenna 25. The radio interface may correspond to one or more of various radio access technologies, including GSM, LTE, LTE-A, 5G, NR, WLAN, NB-IoT, Bluetooth, BT-LE, NFC, RFID, UWB, etc. The radio interface may include other components such as filters, converters (e.g., digital-to-analog converters), symbol demappers, signal shaping components, inverse fast Fourier transform (IFFT) modules, etc., to process symbols carried by the downlink or uplink, such as OFDMA symbols.

[0113] For example, transceiver 28 may be configured to modulate information onto a carrier waveform for transmission by antenna(s)25 and demodulate information received via antenna(s)25 for further processing by other elements of device 20. In other embodiments, transceiver 28 may be able to directly transmit and receive signals or data. Additionally or alternatively, in some embodiments, device 20 may include input and / or output devices (I / O devices). In some embodiments, device 20 may also include a user interface, such as a graphical user interface or a touchscreen.

[0114] In one embodiment, memory 24 stores software modules that provide functionality when executed by processor 22. These modules may include, for example, an operating system that provides operating system functionality to device 20. The memory may also store one or more functional modules, such as applications or programs, to provide additional functionality to device 20. Components of device 20 may be implemented in hardware or as any suitable combination of hardware and software. According to an example embodiment, device 20 may optionally be configured to communicate with device 10 or device 30 via a wireless or wired communication link or interface 70 according to any radio access technology such as NR.

[0115] According to some embodiments, the processor 22 and the memory 24 may be included in or form part of a processing circuitry or control circuitry. Furthermore, in some embodiments, the transceiver 28 may be included in or form part of a transceiver circuitry.

[0116] As described above, according to some embodiments, device 20 may be a UE (e.g., SL UE), a mobile device, a mobile station, a ME, an IoT device, and / or an NB-IoT device. According to some embodiments, device 20 may be controlled by memory 24 and processor 22 to perform functions associated with the example embodiments described herein. For example, in some embodiments, device 20 may be configured to perform one or more processes depicted in any flowchart or signaling diagram described herein, such as... Figures 1-4 , Figure 5a or Figure 5b As shown. In some embodiments, device 20 may include or represent a UE, such as an SL UE. In one example embodiment, device 20 may represent an SL TX UE, such as... Figure 1 As shown in the example. According to one embodiment, device 10 can be configured to perform processes related to monitoring and improving the PC5-RRC (re)configuration process in NR SL.

[0117] In some embodiments, device 20 may be controlled by memory 24 and processor 22 to determine whether a radio problem exists. For example, a radio problem may include a physical layer problem, a connection re-establishment process, or a handover process via the interface between the SL UE and the network (e.g., the Uu interface). In one embodiment, when it is determined that no radio problem exists (e.g., no physical layer problem, no connection re-establishment process via the Uu interface, and / or no handover process is performed), device 20 may be controlled by memory 24 and processor 22 to construct an RRC reconfiguration sidechain message. According to some embodiments, device 20 may be controlled by memory 24 and processor 22 to transmit the RRC reconfiguration sidechain message to the lower layer and start a timer (e.g., timer T400) for monitoring the PC5 RRC (re)configuration process. For example, in one embodiment, the RRC layer of device 20 may be controlled to send the RRC reconfiguration sidechain message to the lower layer only if there is no physical layer problem, connection re-establishment process, or handover process via the Uu interface. Otherwise, when a radio problem is identified (e.g., a physical layer problem via the Uu interface, or a connection re-establishment or switching process), device 20 may be controlled by memory 24 and processor 22 to not start a timer (e.g., timer T400) for monitoring the PC5 RRC (re)configuration process. In some embodiments, if an RRC reconfiguration sidechain message is transmitted and timer T400 is started, device 20 may be controlled by memory 24 and processor 22 to maintain the value of the timer (e.g., T400) once device 20 detects a physical layer problem or a connection re-establishment or switching process via an interface (e.g., the Uu interface).

[0118] For example, in one embodiment, to determine if a physical layer problem exists, device 20 may be controlled by memory 24 and processor 22 to check if timer T310 is running, indicating that device 20 has detected a continuous N310 desynchronization indication from the lower layer regarding the Uu interface. Therefore, if timer T400 starts without noticing that timer T310 is running, timer T400 may expire before the physical layer problem is resolved, leading to the release of the PC5 link, which is unreasonable as it does not reflect the state of the PC5 link. In this embodiment, when a physical layer problem is determined to exist, device 20 may be controlled by memory 24 and processor 22 to construct an RRC reconfiguration sidechain message after the physical layer problem is resolved (e.g., when timer T310 stops).

[0119] If device 20 is attempting to perform a Uu connection re-establishment process, for example, while timer T301 or T311 is running, a similar approach can be applied. In this case, when a connection re-establishment process via an interface (e.g., the Uu interface) is determined to exist, device 20 cannot obtain SL resources from the network before the Uu connection is re-established. Therefore, T400 should not be initiated in this case to avoid T400 expiring before the Uu connection is established, as it would release the PC5 link if T400 expires. Furthermore, if the UE re-establishes a Uu connection to a new cell, it can obtain a new PC5 configuration from the new cell. Therefore, when a connection re-establishment process via an interface (e.g., the Uu interface) is determined to exist, device 20 can be controlled by memory 24 and processor 22 to construct an RRC reconfiguration sidechain message after the connection is re-established.

[0120] In another example, after receiving an RRCReconfiguration message including reconfigurationWithSync, device 20 can be controlled by memory 24 and processor 22 to start its timer T304 and perform a handover to the corresponding special cell (SpCell). Therefore, device 20 cannot request sidelink resources from the network until the handover process is successful. Similarly, since device 20 can obtain the new PC5 configuration from the target cell, it is reasonable for device 20 to wait and construct an RRCReconfigurationSidelink message after the handover process.

[0121] In one embodiment, device 20 may be controlled by memory 24 and processor 22 to construct and transmit RRC reconfiguration sidechain messages and start a timer (e.g., timer T400) for monitoring the PC5 RRC (re)configuration process. According to one embodiment, after constructing and transmitting the RRC reconfiguration sidechain messages and starting the timer, device 20 may be controlled by memory 24 and processor 22 to detect the presence of a radio problem (e.g., a physical layer problem via the Uu interface, a connection re-establishment process, or a handover process). In one embodiment, device 20 may be controlled by memory 24 and processor 22 to maintain the value of the timer (e.g., T400) until the radio problem is resolved.

[0122] Therefore, in one embodiment, when a physical layer problem is detected or a connection re-establishment process is initiated after constructing the RRC reconfiguration sidechain message and starting the T400 timer, device 20 can be controlled by memory 24 and processor 22 to maintain the value of timer T400 until the physical layer problem is resolved, the connection re-establishment is completed, the handover process is completed, or device 20 enters RRC idle mode. For example, when a physical layer problem is detected (e.g., timer T310 starts or radio channel conditions are worse than the configured threshold), device 20 can be controlled by memory 24 and processor 22 to put timer T400 into a waiting state (in other words, timer T400 will stop, but its value will not be reset to 0). Once the physical layer problem is resolved in the same serving cell (e.g., T310 stops or radio channel conditions are better than the configured threshold), device 20 can be controlled by memory 24 and processor 22 to restart timer T400.

[0123] In one embodiment, when a connection re-establishment process is initiated (e.g., due to the maximum number of retransmissions via the Uu interface being reached, or a handover failure causing RLC failure) or a handover process is started, device 20 may be controlled by memory 24 and processor 22 to place timer T400 in a waiting state. After a successful Uu re-establishment with the same serving cell, device 20 may be controlled by memory 24 and processor 22 to continue running timer T400. After a successful connection re-establishment or handover with the new serving cell, or when the UE enters RRC idle mode without a successful connection re-establishment, device 20 may be controlled by memory 24 and processor 22 to check whether the PC5 configuration obtained from the new serving cell (in the case of a successful Uu re-establishment) or SIB / pre-configuration (in the case of entering idle mode) conforms to the configuration in the constructed RRC reconfiguration sidechain message. If it conforms, device 20 may be controlled by memory 24 and processor 22 to restart timer T400. When entering idle mode and switching to SL mode 2, device 20 can be controlled by memory 24 and processor 22 to start timer T400 once the sensing result at device 20 is available for using SL mode 2. If not, device 20 can be controlled by memory 24 and processor 22 to construct a new RRC reconfiguration sidelink message and restart timer T400 accordingly once the sensing result is available for using SL mode 2 (i.e., the value of T400 will be reset to 0 and T400 will start again). For example, in this case, device 20 can be controlled by memory 24 and processor 22 to construct a new RRC reconfiguration sidelink message and restart timer T400 when the new RRC reconfiguration sidelink message is transmitted.

[0124] In one example, if the connection re-establishment or handover process fails, device 20 can be controlled by memory 24 and processor 22 to switch to SL mode 2 (i.e., UE autonomous resource selection mode). In this case, device 20 can be controlled by memory 24 and processor 22 to check whether the configuration obtained from SIB / pre-configuration matches the configuration in the constructed RRC reconfiguration sidechain message. If it matches, device 20 can be controlled by memory 24 and processor 22 to start timer T400 once the sensing result is available for using SL mode 2. If it does not match, device 20 can be controlled by memory 24 or processor 22 to construct a new RRC reconfiguration sidechain message accordingly once the sensing result is available for using SL mode 2. Furthermore, device 20 can be controlled by memory 24 and processor 22 to restart timer T400 when the new RRC reconfiguration sidechain message is transmitted to the lower layer.

[0125] In some embodiments, device 20 may be configured by the network with multiple values ​​for timers (e.g., T400 timers) or multiple different similar timers associated with the same PC5-RRC procedure. According to some examples, different values ​​or timers can be used or configured based on different conditions experienced from the interface between device 20 and the network (e.g., the Uu interface) if a physical layer problem or connection re-establishment or handover procedure occurs via the (Uu) interface. For example, one value and / or timer may be used if a Uu physical layer problem is not detected and a connection re-establishment or handover procedure is not initiated. Another value and / or timer may be configured to be used, for example, when a physical layer problem is detected. In this case, upon detection of such a physical layer problem, the RRC layer may update a constant that will be used to detect the expiration of the timer (e.g., the T400 timer). Another value and / or timer may be configured to be used, for example, when a connection re-establishment is initiated. Another value and / or timer may be configured to be used, for example, when a handover procedure is initiated. Furthermore, another value and / or timer can be configured, for example, when device 20 uses the exception resource pool to transmit RRC reconfiguration sidechain messages.

[0126] In one embodiment, when an RRC reconfiguration sidechain message has been sent to the lower layer and a timer (e.g., a T400 timer) has started, device 20 can be configured by the network to extend the timer (e.g., the T400 timer) upon detection of a physical layer problem or the initiation of a connection re-establishment process. According to some examples, device 20 can be configured with extension values ​​corresponding to the conditions described above, such as experiencing a physical layer problem, performing a connection re-establishment, or using an abnormal resource pool. In one example, the timer extension can be associated with a timer configured to monitor the physical layer recovery process or the connection re-establishment process.

[0127] Figure 6c An example of device 30 according to another exemplary embodiment is shown. In one exemplary embodiment, device 30 may be a node or element in or associated with a communication network, such as a UE, mobile device (ME), mobile station, mobile device, fixed device, IoT device, or other device. As described herein, UE may alternatively be referred to as, for example, mobile station, mobile equipment, mobile unit, mobile device, user equipment, subscriber station, wireless terminal, tablet computer, smartphone, IoT device or NB-IoT device, connected vehicle, etc. As an example, device 30 may be implemented in, for example, a wireless handheld device, a wireless plug-in accessory, etc.

[0128] In some example embodiments, device 30 may include one or more processors, one or more computer-readable storage media (e.g., memory, storage device, etc.), one or more radio access components (e.g., modem, transceiver, etc.), and / or a user interface. In some example embodiments, device 30 may be configured to operate using one or more radio access technologies, such as GSM, LTE, LTE-A, NR, 5G, WLAN, WiFi, NB-IoT, MulteFire, and / or any other radio access technology. It should be noted that those skilled in the art will understand that device 30 may include... Figure 6c Components or features not shown in the diagram.

[0129] like Figure 6c As shown in the example, device 30 may include or be coupled to processor 32 for processing information and executing instructions or operations. Processor 32 may be any type of general-purpose or special-purpose processor. In practice, processor 32 may include one or more of the following: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), and processor based on a multi-core processor architecture. Although Figure 6c A single processor 32 is shown, but multiple processors may be used according to other example embodiments. For example, it should be understood that in some example embodiments, device 30 may include two or more processors, which may form a multiprocessor system capable of supporting multiple processing (e.g., in this case, processor 32 may represent multiple processors). In some example embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0130] The processor 32 can perform functions associated with the operation of the device 30, including, for example, precoding of antenna gain / phase parameters, encoding and decoding of individual bits forming communication messages, formatting of information, and overall control of the device 30, including processes related to the management of communication resources.

[0131] Device 30 may also include or be coupled to memory 34 (internal or external), which may be coupled to processor 32 for storing information and instructions executable by processor 32. Memory 34 may be one or more memories and may be of any type suitable for the local application environment, and may be implemented using any suitable volatile or non-volatile data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and / or removable memory. For example, memory 34 may include random access memory (RAM), read-only memory (ROM), static storage devices such as disks or optical discs, hard disk drives (HDDs), or any combination of any other type of non-transitory machine or computer-readable medium. Instructions stored in memory 34 may include program instructions or computer program code that, when executed by processor 32, enable device 30 to perform the tasks described herein.

[0132] In one example embodiment, device 30 may also include or be coupled to an (internal or external) drive or port configured to accept and read external computer-readable storage media, such as an optical disc, USB drive, flash drive, or any other storage media. For example, the external computer-readable storage media may store computer programs or software that can be executed by processor 32 and / or device 30.

[0133] In some example embodiments, device 30 may also include or be coupled to one or more antennas 35 for receiving downlink signals and / or for transmission from device 30 via an uplink. Device 30 may also include a transceiver 38 configured to transmit and receive information. Transceiver 38 may also include a radio interface (e.g., a modem) coupled to antenna 35. The radio interface may correspond to a variety of radio access technologies, including one or more of GSM, LTE, LTE-A, 5G, NR, WLAN, NB-IoT, BT-LE, RFID, UWB, etc. The radio interface may include other components such as filters, converters (e.g., digital-to-analog converters), symbol demappers, signal shaping components, inverse fast Fourier transform (IFFT) modules, etc., to process symbols carried by the downlink or uplink, such as OFDMA symbols.

[0134] For example, transceiver 38 may be configured to modulate information onto a carrier waveform for transmission by antenna(s)35 and demodulate information received via antenna(s)35 for further processing by other elements of device 30. In other example embodiments, transceiver 38 may be able to directly transmit and receive signals or data. Additionally or alternatively, in some embodiments, device 30 may include input and / or output devices (I / O devices). In some example embodiments, device 30 may also include a user interface, such as a graphical user interface or a touchscreen.

[0135] In one example embodiment, memory 34 stores software modules that provide functionality when executed by processor 32. These modules may include, for example, an operating system that provides operating system functionality to device 30. The memory may also store one or more functional modules, such as applications or programs, to provide additional functionality to device 30. Components of device 30 may be implemented in hardware or as any suitable combination of hardware and software. According to one example embodiment, device 30 may optionally be configured to communicate with device 10 via wireless or wired communication link 71 or with device 20 via wireless or wired communication link 72, according to any wireless access technology such as NR.

[0136] According to some example embodiments, the processor 32 and the memory 34 may be included in or form part of a processing circuitry or control circuitry. Furthermore, in some example embodiments, the transceiver 38 may be included in or form part of a transceiver circuitry.

[0137] As described above, according to some example embodiments, device 30 may be a UE (e.g., SL UE), a mobile device, a mobile station, a ME, an IoT device, and / or an NB-IoT device. According to some example embodiments, device 30 may be controlled by memory 34 and processor 32 to perform functions associated with the example embodiments described herein. For example, in some example embodiments, device 30 may be configured to perform one or more processes depicted in any diagram or signaling flowchart described herein. For example, device 30 may correspond to or represent a UE, such as... Figure 1 One or more of the UEs shown, such as the SLRX UE. According to some example embodiments, for example, device 30 may be configured to perform processes related to monitoring and improving the PC5-RRC (re)configuration process in the NR SL.

[0138] In some embodiments, the device 30 may be controlled by the memory 34 and the processor 32 to receive RRC reconfiguration sidechain messages from the SL UE (e.g., SL TX UE or device 20) and transmit RRC reconfiguration complete sidechain messages to the SL UE (e.g., SL TX UE or device 20).

[0139] Therefore, certain example embodiments provide several technical improvements, enhancements, and / or advantages over prior art processes, and constitute improvements at least in the technical field of wireless network control and management. For example, some embodiments enable the SL UE to avoid PC5-RRC radio link failures, such as failures due to Uu radio link problems. Thus, according to example embodiments, the SL UE can maintain V2X service because PC5 connectivity and communication can continue. Therefore, the use of certain example embodiments improves the functionality of the communication network and its nodes (such as base stations, eNBs, gNBs, and / or UEs or mobile stations).

[0140] In some example embodiments, the functionality of any methods, processes, signaling diagrams, algorithms, or flowcharts described herein may be implemented by software and / or computer program code or code portions stored in memory or other computer-readable or tangible media and executed by a processor.

[0141] In some example embodiments, an apparatus may be included in or associated with at least one software application, module, unit, or entity configured to perform arithmetic operations, or configured to be a program or a portion thereof (including added or updated software routines) executed by at least one operating processor. The program (also referred to as a program product or computer program, including software routines, applets, and macros) may be stored in any device-readable data storage medium and may include program instructions for performing a specific task.

[0142] A computer program product may include one or more computer-executable components that, when the program runs, are configured to perform some example embodiments. The one or more computer-executable components may be at least one piece of software code or code. Modifications and configurations required to implement the functionality of the example embodiments may be executed as routines(s), which may be implemented as added or updated software routines(s). In one example, software routines(s) may be downloaded to the device.

[0143] As an example, software or computer program code or code portions may be in the form of source code, object code, or some intermediate form, and may be stored on some carrier, distribution medium, or computer-readable medium, which may be any entity or device capable of carrying the program. For example, such a carrier may include recording media, computer memory, read-only memory, optoelectronic and / or electrical carrier signals, telecommunication signals, and / or software distribution packages. Depending on the required processing power, the computer program may execute in a single electronic digital computer or be distributed across multiple computers. The computer-readable medium or computer-readable storage medium may be a non-transitory medium.

[0144] In other example embodiments, the function may be performed by hardware or circuitry systems included in the device, such as by using an application-specific integrated circuit (ASIC), a programmable gate array (PGA), a field-programmable gate array (FPGA), or any other combination of hardware and software. In yet another example embodiment, the function may be implemented as a signal, such as an intangible component that can be carried by an electromagnetic signal downloaded from the Internet or another network.

[0145] According to the example embodiments, devices such as nodes, equipment or corresponding components can be configured as circuit systems, computers or microprocessors, such as monolithic computer elements, or configured as chipsets, which may include at least a memory for providing storage capacity for arithmetic operations(s) and / or an arithmetic processor for performing arithmetic operations(s).

[0146] It will be readily understood by those skilled in the art that the exemplary embodiments discussed above can be practiced with a different sequence of processes and / or with different configurations of hardware elements compared to those disclosed. Therefore, although some embodiments have been described based on these exemplary embodiments, it will be apparent to those skilled in the art that certain modifications, variations, and alternative constructions will be readily apparent while remaining within the spirit and scope of the exemplary embodiments.

Claims

1. A method for communication, comprising: determining, at a sidelink (SL) user equipment (UE), whether an interface between the sidelink (SL) user equipment (UE) and a network node has a radio problem; generating or constructing a radio resource control (RRC) reconfiguration sidelink message when it is determined that the interface does not have a radio problem, the method further comprising: when it is determined that the interface between the sidelink (SL) user equipment (UE) and the network node has a radio problem, maintaining a value of a timer for monitoring a PC5-radio resource control (RRC) configuration procedure until the radio problem of the interface is resolved, wherein determining that the interface has a radio problem comprises detecting a physical layer problem via a Uu interface, or initiation of a connection re-establishment procedure or a handover procedure, wherein, after a successful connection re-establishment or a successful handover procedure with a new serving cell, or when the sidelink (SL) user equipment (UE) enters a radio resource control (RRC) idle mode without a successful connection re-establishment or handover, the method comprises: checking whether a PC5 configuration, or a system information block (SIB) / pre-configuration acquired from the new serving cell, complies with a configuration in the constructed radio resource control (RRC) reconfiguration sidelink message; if the PC5 configuration or the system information block (SIB) / pre-configuration complies, restarting the timer with an existing value; and if the PC5 configuration or the system information block (SIB) / pre-configuration does not comply, constructing a new radio resource control (RRC) reconfiguration sidelink message accordingly and restarting the timer with an initial value.

2. The method of claim 1, wherein the determination of whether a radio problem exists comprises: determining whether there is a physical layer problem or a connection re-establishment procedure or a handover procedure via an interface between the sidelink (SL) user equipment (UE) and the network node; and when it is determined that there is no physical layer problem or a connection re-establishment procedure or a handover procedure via the interface, the method comprises transmitting the radio resource control (RRC) reconfiguration sidelink message to a lower layer and starting a timer.

3. The method of any one of claims 1 or 2, wherein the determination of whether there is a radio problem comprises determining at least one of: whether one or more exceptional resource pools are configured; or whether the sidelink (SL) user equipment (UE) has received configured grant type resources before the radio problem was detected.

4. The method of claim 1 or 2, wherein the construction of the radio resource configuration (RRC) reconfiguration sidelink message is performed at the radio resource control (RRC) layer of the sidelink (SL) user equipment (UE). if there is no physical layer problem or a connection re-establishment procedure or a handover procedure, sending the radio resource control (RRC) reconfiguration sidelink message to the lower layer via the radio resource control (RRC) layer at the sidelink (SL) user equipment (UE).

5. The method of claim 2, wherein the transmitting comprises:

5. A network node for communication, comprising: a processor configured to determine whether an interface between the network node and a sidelink (SL) user equipment (UE) has a radio problem; and a transmitter configured to transmit a radio resource control (RRC) reconfiguration sidelink message when it is determined that the interface does not have a radio problem, the network node further comprising: a receiver configured to receive a PC5-radio resource control (RRC) configuration message from the sidelink (SL) user equipment (UE) when it is determined that the interface between the network node and the sidelink (SL) user equipment (UE) has a radio problem, wherein the processor is configured to maintain a value of a timer for monitoring a PC5-radio resource control (RRC) configuration procedure until the radio problem of the interface is resolved, wherein the processor is configured to determine that the interface has a radio problem by detecting a physical layer problem via a Uu interface, or initiation of a connection re-establishment procedure or a handover procedure, wherein, after a successful connection re-establishment or a successful handover procedure with a new serving cell, or when the sidelink (SL) user equipment (UE) enters a radio resource control (RRC) idle mode without a successful connection re-establishment or handover, the processor is configured to: check whether a PC5 configuration, or a system information block (SIB) / pre-configuration acquired from the new serving cell, complies with a configuration in the received radio resource control (RRC) reconfiguration sidelink message; if the PC5 configuration or the system information block (SIB) / pre-configuration complies, restart the timer with an existing value; and if the PC5 configuration or the system information block (SIB) / pre-configuration does not comply, construct a new radio resource control (RRC) reconfiguration sidelink message accordingly and restart the timer with an initial value. determine whether there is a physical layer problem or a connection re-establishment procedure or a handover procedure via an interface between the network node and the sidelink (SL) user equipment (UE); and when it is determined that there is no physical layer problem or a connection re-establishment procedure or a handover procedure via the interface, the processor is configured to transmit the radio resource control (RRC) reconfiguration sidelink message to a lower layer and start a timer.

6. The network node of any one of claims 5, wherein the determination of whether there is a radio problem comprises determining at least one of: whether one or more exceptional resource pools are configured; or whether the sidelink (SL) user equipment (UE) has received configured grant type resources before the radio problem was detected.

7. The network node of claim 5 or 6, wherein the radio resource control (RRC) reconfiguration sidelink message is received at the radio resource control (RRC) layer of the network node.

8. The network node of any one of claims 5 to 7, wherein the transmitter is configured to transmit the radio resource control (RRC) reconfiguration sidelink message to the lower layer via the radio resource control (RRC) layer at the network node if there is no physical layer problem or a connection re-establishment procedure or a handover procedure.

6. The method of claim 2, wherein, When it is determined that there is a physical layer problem or a connection re-establishment procedure or a handover procedure via the interface, the method comprises not generating or constructing the radio resource control (RRC) reconfiguration sidelink message and not starting the timer for monitoring the PC5-radio resource control (RRC) configuration procedure.

7. The method of claim 1 or 2, wherein the determining comprises: checking one or more timers configured for monitoring at least one of a physical layer recovery procedure, the connection re-establishment procedure, or the handover procedure.

8. The method of claim 1 or 2, wherein when it is determined that there is a connection reestablishment procedure or a handover procedure via the interface, the constructing comprises: constructing the radio resource control (RRC) reconfiguration sidelink message after the connection re-establishment or handover to a target cell.

9. An apparatus for communication, comprising: at least one processor; and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: determining whether there is a radio problem for an interface between the apparatus and a network node; when it is determined that there is no radio problem for the interface, generating or constructing a radio resource control (RRC) reconfiguration sidelink message, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: when it is determined that there is a radio problem for the interface between the apparatus and the network node, maintaining a value of a timer for monitoring a PC5-radio resource control (RRC) configuration procedure until the radio problem for the interface is resolved, wherein determining that there is a radio problem for the interface comprises detecting initiation of a physical layer problem or a connection re-establishment procedure or a handover procedure via a Uu interface, wherein, after a successful connection re-establishment or a successful handover procedure with a new serving cell, or when the apparatus enters a radio resource control (RRC) idle mode without a successful connection re-establishment or handover, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: checking whether a PC5 configuration or a system information block (SIB) / pre-configuration acquired from the new serving cell complies with a configuration in the constructed radio resource control (RRC) reconfiguration sidelink message; if the PC5 configuration or the system information block (SIB) / pre-configuration complies, restarting the timer with an existing value; and if the PC5 configuration or the system information block (SIB) / pre-configuration does not comply, constructing a new radio resource control (RRC) reconfiguration sidelink message accordingly and restarting the timer with an initial value.

10. The apparatus of claim 9, wherein the determination of whether a radio problem exists comprises: determining whether there is a physical layer problem or a connection re-establishment procedure or a handover procedure via an interface between the apparatus and the network node; and When it is determined that there is no physical layer problem or connection re-establishment procedure or handover procedure via the interface, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: transmitting the radio resource control (RRC) reconfiguration sidelink message to a lower layer and starting a timer.

11. The apparatus of any one of claims 9 or 10, wherein the determination of whether there is a radio problem comprises determining at least one of: whether one or more exceptional resource pools are configured; or whether the apparatus has received configured grant type resources prior to the radio problem being detected.

12. The apparatus of claim 9 or 10, wherein the construction of the radio resource configuration (RRC) reconfiguration sidelink message is performed at the radio resource control (RRC) layer of the apparatus.

13. The apparatus of claim 10, wherein the transmission comprises: If there is no physical layer problem or connection re-establishment procedure or handover procedure, sending, at the apparatus, the radio resource control (RRC) reconfiguration sidelink message to the lower layer via the radio resource control (RRC) layer.

14. The apparatus of claim 10, wherein, When it is determined that there is a physical layer problem or connection re-establishment procedure or handover procedure via the interface, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: skipping the generating or constructing the radio resource control (RRC) reconfiguration sidelink message and skipping the starting of the timer for monitoring the PC5-radio resource control (RRC) configuration procedure.

15. The apparatus of claim 9 or 10, wherein the determining comprises: checking one or more timers configured for monitoring at least one of a physical layer recovery procedure, the connection re-establishment procedure, or the handover procedure.

16. The apparatus of claim 9 or 10, wherein, When it is determined that there is a connection re-establishment procedure or handover procedure via the interface, the constructing comprises: constructing the radio resource control (RRC) reconfiguration sidelink message after the connection re-establishment or handover to a target cell.

17. An apparatus for communication, comprising: means for determining whether an interface between the apparatus and a network node has a radio problem; means for generating or constructing a radio resource control (RRC) reconfiguration sidelink message when it is determined that the interface does not have a radio problem, The apparatus further comprises: means for maintaining a value of a timer for monitoring a PC5-radio resource control (RRC) configuration procedure when it is determined that the interface between the apparatus and the network node has a radio problem until the radio problem of the interface is resolved, wherein the means for determining that the interface has the radio problem comprises means for detecting initiation of a physical layer problem or a connection re-establishment procedure or a handover procedure via a Uu interface, wherein, after a successful connection re-establishment or a successful handover procedure with a new serving cell, or when the apparatus enters a radio resource control (RRC) idle mode without a successful connection re-establishment or handover, the apparatus comprises means for: checking whether a PC5 configuration, or a system information block (SIB) / pre-configuration acquired from the new serving cell, complies with a configuration in the radio resource control (RRC) reconfiguration sidelink message constructed; if the PC5 configuration or the system information block (SIB) / pre-configuration complies, restarting the timer with an existing value; and if the PC5 configuration or the system information block (SIB) / pre-configuration does not comply, constructing a new radio resource control (RRC) reconfiguration sidelink message accordingly and restarting the timer with an initial value.

18. The apparatus of claim 17, wherein the means for determining whether a radio problem exists comprises: means for determining whether there is a physical layer problem or a connection re-establishment procedure or a handover procedure via an interface between the apparatus and the network node; and when it is determined that there is no physical layer problem or a connection re-establishment procedure or a handover procedure via the interface, the apparatus comprises means for transmitting the radio resource control (RRC) reconfiguration sidelink message to a lower layer and starting a timer.

19. The apparatus of any one of claims 17 or 18, wherein the means for determining whether there is a radio problem comprises means for determining at least one of: whether one or more exceptional resource pools are configured; or whether the apparatus received configured grant type resources before the radio problem was detected.

20. The apparatus of claims 17 or 18, wherein the means for constructing the radio resource control (RRC) reconfiguration sidelink message is performed at the radio resource control (RRC) layer of the apparatus.

21. The apparatus of claim 18, wherein the means for transmitting comprises: means for sending the radio resource control (RRC) reconfiguration sidelink message at the apparatus via the radio resource control (RRC) layer to the lower layer in the absence of a physical layer problem or a connection re-establishment procedure or a handover procedure.

22. The apparatus of claim 18, wherein, when it is determined that there is a physical layer problem or a connection re-establishment procedure or a handover procedure via the interface, the apparatus comprises means for skipping the generating or constructing the radio resource control (RRC) reconfiguration sidelink message and means for skipping the starting of the timer for monitoring the PC5-radio resource control (RRC) configuration procedure.

23. The apparatus of claim 17 or 18, wherein the means for determining comprises: means for checking one or more timers configured for monitoring at least one of a physical layer recovery procedure, the connection re-establishment procedure, or the handover procedure.

24. The apparatus of claim 17 or 18, wherein, when it is determined that there is a connection re-establishment procedure or a handover procedure via the interface, the means for constructing comprises means for constructing the radio resource control (RRC) reconfiguration sidelink message after the connection re-establishment or handover to a target cell.

25. A method for communication, comprising: At a side link (SL) user equipment (UE), a radio resource control (RRC) reconfiguration sidelink message is generated or constructed; and starting a timer for monitoring the PC5-radio resource control (RRC) configuration procedure, the method further comprises: detecting a radio problem at an interface between the side link (SL) user equipment (UE) and a network node; and keeping the value of the timer until the radio problem of the interface is resolved, wherein detecting the radio problem at the interface comprises detecting a physical layer problem via a Uu interface, or initiation of a connection re-establishment procedure or a handover procedure, wherein, after a successful connection re-establishment or a successful handover procedure with a new serving cell, or when the side link (SL) user equipment (UE) enters a radio resource control (RRC) idle mode without a successful connection re-establishment or handover, the method comprises: checking whether a PC5 configuration, or a system information block (SIB) / pre-configuration acquired from the new serving cell, complies with the configuration in the constructed radio resource control (RRC) reconfiguration sidelink message; if the PC5 configuration or the system information block (SIB) / pre-configuration complies, restarting the timer with an existing value; and if the PC5 configuration or the system information block (SIB) / pre-configuration does not comply, constructing a new radio resource control (RRC) reconfiguration sidelink message accordingly and restarting the timer with an initial value.

26. The method of claim 25, wherein, when, after the radio resource control (RRC) reconfiguration sidelink message is constructed and the timer is started, a physical layer problem is detected, or a connection re-establishment procedure or a handover procedure is initiated, the method comprises: keeping the value of the timer until the physical layer problem is resolved, or the connection re-establishment or the handover procedure is completed, or the side link (SL) user equipment (UE) enters an idle mode; and when the physical layer problem is resolved, or the connection re-establishment is performed in the same serving cell, restarting the timer with an existing value.

27. The method of claim 25, wherein, when a connection re-establishment procedure or a handover procedure is initiated, the method comprises putting the timer in a waiting state.

28. The method of claim 25, wherein, when the connection re-establishment procedure or the handover procedure fails, the method comprises: switching to a side link (SL) mode 2; checking whether the configuration acquired from a system information block (SIB) / pre-configuration complies with the configuration in the constructed radio resource control (RRC) reconfiguration sidelink message; if the acquired configuration complies, starting the timer with an existing value as soon as sensing results are available for using a side link (SL) mode 2; if the acquired configuration does not comply, constructing a new radio resource control (RRC) reconfiguration sidelink message accordingly and starting the timer as soon as sensing results are available for using a side link (SL) mode 2.

29. The method of claim 25, wherein the sidelink (SL) user equipment (UE) is configured with multiple values of the timer, or multiple different timers associated with the same PC5-radio resource control (RRC) procedure, and wherein a different value or timer is used depending on a condition experienced from the interface between the sidelink (SL) user equipment (UE) and the network.

30. The method of claim 25, wherein, The sidelink (SL) user equipment (UE) is configured to, when the radio resource control (RRC) reconfiguration sidelink message has been sent to lower layers, and the timer has been started, extend the timer if the detection of a physical layer problem, or the initiation of a connection re-establishment procedure or handover procedure occurs.

31. An apparatus for communication, comprising: at least one processor; and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: generating or constructing a radio resource control (RRC) reconfiguration sidelink message; and starting a timer for monitoring the PC5-radio resource control (RRC) configuration procedure, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: detecting that there is a radio problem with an interface between the apparatus and a network node; and keeping a value of the timer until the radio problem with the interface is resolved, wherein detecting that there is the radio problem with the interface comprises detecting a physical layer problem via a Uu interface, or initiation of a connection re-establishment procedure or handover procedure, wherein, after a successful connection re-establishment or a successful handover procedure with a new serving cell, or when the apparatus enters a radio resource control (RRC) idle mode without a successful connection re-establishment or handover, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: checking whether a PC5 configuration, or a system information block (SIB) / pre-configuration acquired from the new serving cell, complies with a configuration in the constructed radio resource control (RRC) reconfiguration sidelink message; if the PC5 configuration or the system information block (SIB) / pre-configuration complies, restarting the timer with an existing value; and if the PC5 configuration or the system information block (SIB) / pre-configuration does not comply, constructing a new radio resource control (RRC) reconfiguration sidelink message accordingly, and restarting the timer with an initial value.

32. The apparatus of claim 31, wherein, when, after constructing the radio resource control (RRC) reconfiguration sidelink message, and starting the timer, a physical layer problem is detected, or a connection re-establishment procedure or handover procedure is initiated, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: keeping the value of the timer until the physical layer problem is resolved, or the connection re-establishment or the handover procedure is completed, or the device enters idle mode; and starting the timer again with the existing value when the physical layer problem is resolved, or the connection re-establishment is performed in the same serving cell.

33. The apparatus of claim 31, wherein when a connection re-establishment procedure or a handover procedure is initiated, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: putting the timer in a wait state.

34. The apparatus of claim 31, wherein when the connection re-establishment procedure or the handover procedure fails, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: switching to a sidelink (SL) mode 2; checking whether the configuration acquired from a system information block (SIB) / pre-configuration matches the configuration in a constructed radio resource control (RRC) reconfiguration sidelink message; if the acquired configuration matches, starting the timer with the existing value as soon as sensing results are available for using sidelink (SL) mode 2; if the acquired configuration does not match, constructing a new radio resource control (RRC) reconfiguration sidelink message accordingly and starting the timer as soon as sensing results are available for using sidelink (SL) mode 2.

35. The apparatus of claim 31, wherein the apparatus is configured with multiple values of the timer, or multiple different timers associated with the same PC5-radio resource control (RRC) procedure, and wherein the different values or timers are used according to conditions experienced from the interface between the apparatus and the network.

36. The apparatus of claim 31, wherein the apparatus is configured to, when the radio resource control (RRC) reconfiguration sidelink message has been sent to lower layers and the timer has been started, extend the timer if the detection of a physical layer problem, or the initiation of the connection re-establishment procedure or handover procedure, occurs.

37. An apparatus for communication, comprising: means for generating or constructing a radio resource control (RRC) reconfiguration sidelink message; and means for starting a timer for monitoring the PC5-radio resource control (RRC) configuration procedure, the apparatus further comprising: means for detecting a radio problem exists for an interface between the apparatus and a network node; and means for keeping a value of the timer until the radio problem of the interface is resolved, wherein the means for detecting the radio problem exists for the interface comprises means for detecting a physical layer problem via a Uu interface, or initiation of a connection re-establishment procedure or a handover procedure, wherein, after a successful connection re-establishment or a successful handover procedure with a new serving cell, or when the device enters a radio resource control (RRC) idle mode without a successful connection re-establishment or handover, the device comprises means for: checking whether a PC5 configuration, or a system information block (SIB) / pre-configuration acquired from the new serving cell, complies with the configuration in the constructed radio resource control (RRC) reconfiguration sidelink message; if the PC5 configuration or the system information block (SIB) / pre-configuration complies, restarting the timer with an existing value again; and if the PC5 configuration or the system information block (SIB) / pre-configuration does not comply, constructing a new radio resource control (RRC) reconfiguration sidelink message accordingly and restarting the timer with an initial value.

38. The device of claim 37, wherein after the radio resource control (RRC) reconfiguration sidelink message is constructed and the timer is started, when a physical layer problem is detected or a connection re-establishment procedure or a handover procedure is initiated, the device comprises: means for keeping the value of the timer until the physical layer problem is resolved or the connection re-establishment or the handover procedure is completed or the device enters an idle mode; and means for starting the timer again with an existing value when the physical layer problem is resolved or the connection re-establishment is performed in the same serving cell.

39. The device of claim 37, wherein, When a connection re-establishment procedure or a handover procedure is initiated, the device comprises means for putting the timer in a wait state.

40. The device of claim 37, wherein when the connection re-establishment procedure or the handover procedure fails, the device comprises: means for switching to a sidelink (SL) mode 2; means for checking whether the configuration acquired from a system information block (SIB) / pre-configuration complies with the configuration in the constructed radio resource control (RRC) reconfiguration sidelink message; means for starting the timer with an existing value as soon as sensing results are available for using a sidelink (SL) mode 2 in case the acquired configuration complies; means for constructing a new radio resource control (RRC) reconfiguration sidelink message accordingly and for starting the timer in case the acquired configuration does not comply as soon as sensing results are available for using a sidelink (SL) mode 2.

41. The device of claim 37, wherein the device is configured with multiple values of the timer or multiple different timers associated with the same PC5-radio resource control (RRC) procedure, and wherein different values or timers are used depending on conditions experienced from the interface between the device and the network.

42. The apparatus of claim 37, wherein the apparatus is configured to extend the timer if the detection of a physical layer problem, or the initiation of the connection reestablishment procedure or handover procedure, occurs when the radio resource control (RRC) reconfiguration sidelink message has been sent to lower layers and the timer has been started.

43. A computer program product comprising instructions stored thereon for performing at least the method of any one of claims 1 to 8, or 25 to 30.

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