Timing synchronization in a satellite system interruption

Abstract

Various aspects of the present disclosure relate to timing synchronization in scenarios of global navigation satellite system (GNSS) interruption. An apparatus, such as a user equipment (UE), receives first signaling comprising a connectivity indication indicating whether to remain in a connected state or an idle state during a GNSS outage. The apparatus receives second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage. The apparatus performs uplink time synchronization based at least in part on the first signaling and the second signaling.

Description

TIMING SYNCHRONIZATION IN A SATELLITE SYSTEM INTERRUPTIONRELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Application Serial No. 63 / 545,633 filed 25 October 2023 entitled “TIMING SYNCHRONIZATION IN A SATELLITE SYSTEM INTERRUPTION,” the disclosure of which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to wireless communications, and more specifically to device positioning in wireless communications.BACKGROUND

[0003] A wireless communications system may include one or multiple network communication devices, such as base stations, which may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE), or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like). Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g., sixth generation (6G)).SUMMARY

[0004] An article “a” before an element is unrestricted and understood to refer to “at least one” of those elements or “one or more” of those elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” may be interchangeable. As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of’ or “one or more of’ or “one or both of’) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also,as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on”. Further, as used herein, including in the claims, a “set” may include one or more elements.

[0005] Some implementations of the method and apparatuses described herein may further include to receive first signaling including a connectivity indication indicating whether to remain in a connected state or an idle state during a global navigation satellite system (GNSS) outage; receive second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage; and perform uplink time synchronization based at least in part on the first signaling and the second signaling.

[0006] In some implementations of the method and apparatuses described herein, the GNSS outage includes at least one of: a time period during which the UE does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved; the at least one processor is configured to cause the UE to: receive, , third signaling including an indication to report one or more GNSS locations before the GNSS outage; perform, based at least in part on the third signaling, one or more GNSS location estimates based at least in part on a first periodicity; and transmit, based at least in part on a second periodicity, a report including the one or more GNSS location estimates; the report includes a time stamp; the one or more GNSS location estimates include at least one GNSS location estimate prior to the GNSS outage; the at least one processor is configured to cause the UE to transmit the report in response to the GNSS outage.

[0007] In some implementations of the method and apparatuses described herein, a UE transmits a report including one or more parameters for selecting a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for one or more reported GNSS location estimates; the validity distance defines a distance at which a new GNSS position of the UE is different from a previous GNSS position of the UE; the secondsignaling includes a location estimate for timing advance calculation; the at least one processor is configured to cause the UE to: receive third signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; apply the prediction model to predict at least one location estimate; and transmit a report including the at least one location estimate; the at least one processor is configured to cause the UE to receive fourth signaling including a reporting configuration, the reporting configuration includes UE capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; the report includes the at least one location estimate with a time stamp indicating a future time value for using the at least one location estimate.

[0008] In some implementations of the method and apparatuses described herein, a UE receives third signaling including configuration information for estimating a location of the UE based on one or more radio access technology (RAT)-independent techniques that include one or more of wireless local access network (WLAN), Bluetooth, or sensors; estimate a location of the UE based at least in part on the one or more RAT-independent techniques; and apply the estimated location of the UE for calculation of UE-specific timing advance; the second signaling includes an indication to adjust a validity duration for uplink time synchronization; the second signaling includes a medium access control (MAC) control element (CE); the second signaling includes multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS location estimates during the adjusted validity duration; the at least one processor is configured to cause the UE to: perform GNSS measurement autonomously during the adjusted validity duration; and report GNSS availability information during the adjusted validity duration.

[0009] Some implementations of the method and apparatuses described herein may further include receiving first signaling including a connectivity indication indicating whether to remain in a connected state or an idle state during a GNSS outage; receiving second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage; and performing uplink time synchronization based at least in part on the first signaling and the second signaling.

[0010] In some implementations of the method and apparatuses described herein, the GNSS outage includes at least one of: a time period during which the UE does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved; receiving third signaling including an indication to report one or more GNSS locations before the GNSS outage; performing, based at least in part on the third signaling, one or more GNSS location estimates based at least in part on a first periodicity; and transmitting, based at least in part on a second periodicity, a report including the one or more GNSS location estimates; the report includes a time stamp; the one or more GNSS location estimates include at least one GNSS location estimate prior to the GNSS outage; transmitting the report in response to the GNSS outage; transmitting a report including one or more parameters for selecting a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for one or more reported GNSS location estimates; the validity distance defines a distance at which a new GNSS position of the UE is different from a previous GNSS position of the UE.

[0011] In some implementations of the method and apparatuses described herein, the second signaling includes a location estimate for timing advance calculation; receiving third signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; applying the prediction model to predict at least one location estimate; and transmitting a report including the at least one location estimate; receiving fourth signaling including a reporting configuration, the reporting configuration includes UE capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; the report includes the at least one location estimate with a time stamp indicating a future time value for using the at least one location estimate; receiving third signaling including configuration information for estimating a location of the UE based on one or more radio access technology (RAT)-independent techniques that include one or more of WLAN, Bluetooth, or sensors; estimating a location of the UE based at least in part on the one or more RAT-independent techniques; and applying the estimated location of the UE for calculation of UE-specific timing advance.

[0012] In some implementations of the method and apparatuses described herein, the second signaling includes an indication to adjust a validity duration for uplink time synchronization; the second signaling includes a MAC CE; the second signaling includes multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS location estimates during the adjusted validity duration; performing GNSS measurement autonomously during the adjusted validity duration; and reporting GNSS availability information during the adjusted validity duration.

[0013] Some implementations of the method and apparatuses described herein may further include to receive first signaling including a connectivity indication indicating whether to remain in a connected state or an idle state during a GNSS outage; receive second signaling including a timing advance adjustment procedure to apply for time synchronization during the GNSS outage; and perform uplink time synchronization based at least in part on the first signaling and the second signaling.

[0014] In some implementations of the method and apparatuses described herein, the GNSS outage includes at least one of: a time period during which a user equipment (UE) does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS- based positioning may not be achieved; receive third signaling including an indication to report one or more GNSS locations before the GNSS outage; perform, based at least in part on the third signaling, one or more GNSS location estimates based at least in part on a first periodicity; and transmit, based at least in part on a second periodicity, a report including the one or more GNSS location estimates; the report includes a time stamp; the one or more GNSS location estimates include at least one GNSS location estimate prior to the GNSS outage; the processor can transmit the report in response to the GNSS outage.

[0015] Some implementations of the method and apparatuses described herein include to transmit a report including one or more parameters for choosing a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for oneor more reported GNSS location estimates; the validity distance defines a distance at which a new GNSS position of a user equipment (UE) is different from a previous GNSS position of the UE; the second signaling includes a location estimate to be used for timing advance calculation; to receive third signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; apply the prediction model to predict at least one location estimate; and transmit a report including the at least one location estimate; to receive fourth signaling including a reporting configuration, the reporting configuration includes user equipment (UE) capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; the report includes the at least one location estimate with a time stamp indicating a future time value for using the at least one location estimate.

[0016] Some implementations of the method and apparatuses described herein include to receive third signaling including configuration information for estimating a location of a user equipment (UE) based on one or more radio access technology (RAT)-independent techniques that include one or more of WLAN, Bluetooth, or sensors; estimate a location of the UE based at least in part on the one or more RAT-independent techniques; and apply the estimated location of the UE for calculation of UE-specific timing advance; the second signaling includes an indication to adjust (e.g., extend) a validity duration for uplink time synchronization; the second signaling includes a MAC CE; the second signaling includes multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS location estimates during the adjusted validity duration; to perform GNSS measurement autonomously during the adjusted validity duration; and report GNSS availability information during the adjusted validity duration.

[0017] Some implementations of the method and apparatuses described herein may further include to transmit first signaling including a connectivity indication indicating whether a user equipment (UE) is to remain in a connected state or an idle state during a GNSS outage; and transmit second signaling including a timing advance adjustment procedure to apply for time synchronization during the GNSS outage.

[0018] In some implementations of the method and apparatuses described herein, the GNSS outage includes at least one of: a time period during which the UE does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved; to transmit third signaling including an indication to report one or more GNSS locations before the GNSS outage; and receive a report including the one or more GNSS location estimates; to receive a report including one or more parameters for selecting a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for one or more reported GNSS location estimates; the validity distance defines a distance at which a new GNSS position of the UE is different from a previous GNSS position of the UE; the second signaling includes a location estimate for timing advance calculation.

[0019] Some implementations of the method and apparatuses described herein include to transmit third signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; and receive a report including the at least one location estimate; to transmit fourth signaling including a reporting configuration, the reporting configuration includes UE capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; to transmit third signaling including configuration information for estimating a location of the UE based on one or more radio access technology (RAT)-independent techniques that include one or more of WLAN, Bluetooth, or sensors; the second signaling includes an indication to adjust a validity duration for uplink time synchronization; the second signaling includes a MAC CE; the second signaling includes multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS location estimates during the adjusted validity duration; to receive a report including GNSS availability information during the adjusted validity duration.

[0020] Some implementations of the method and apparatuses described herein may further include transmitting first signaling including a connectivity indication indicating whether a userequipment (UE) is to remain in a connected state or an idle state during a GNSS outage; and transmitting second signaling including a timing advance adjustment procedure to apply for time synchronization during the GNSS outage.

[0021] In some implementations of the method and apparatuses described herein, the GNSS outage includes at least one of: a time period during which the UE does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved; transmitting third signaling including an indication to report one or more GNSS locations before the GNSS outage; and receiving a report including one or more GNSS location estimates; receiving a report including one or more parameters for selecting a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for one or more reported GNSS location estimates; the validity distance defines a distance at which a new GNSS position of the UE is different from a previous GNSS position of the UE; the second signaling includes a location estimate for timing advance calculation; transmitting third signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; and receiving a report including the at least one location estimate.

[0022] Some implementations of the method and apparatuses described herein further include transmitting fourth signaling including a reporting configuration, the reporting configuration includes UE capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; transmitting third signaling including configuration information for estimating a location of the UE based on one or more radio access technology (RAT)-independent techniques that include one or more of WLAN, Bluetooth, or sensors; the second signaling includes an indication to adjust a validity duration for uplink time synchronization; the second signaling includes a MAC CE; the second signaling includes multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS location estimates during the adjustedvalidity duration; receiving a report including GNSS availability information during the adjusted validity duration.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 illustrates an example of a wireless communications system in accordance with aspects of the present disclosure.

[0024] Figure 2 illustrates an example 200 of timing relationship for collocated gNB and nonterrestrial network (NTN) gateway in accordance with aspects of the present disclosure.

[0025] Figures 3A and 3B illustrate an example information element 300 in accordance with aspects of the present disclosure.

[0026] Figure 4 illustrates an example of an information element 400 in accordance with aspects of the present disclosure.

[0027] Figure 5 illustrates an example of a scenario 500 for an enhanced timing advance (TA) procedure in accordance with aspects of the present disclosure.

[0028] Figure 6 illustrates an example of a UE 600 in accordance with aspects of the present disclosure.

[0029] Figure 7 illustrates an example of a processor 700 in accordance with aspects of the present disclosure.

[0030] Figure 8 illustrates an example of a network element (NE) 800 in accordance with aspects of the present disclosure.

[0031] Figure 9 illustrates a flowchart of a method 900 in accordance with aspects of the present disclosure.

[0032] Figure 10 illustrates a flowchart of a method 1000 in accordance with aspects of the present disclosure.DETAILED DESCRIPTION

[0033] In wireless communications systems, for a UE to access NR NTN and / or loT NTN, the UE utilizes GNSS capabilities. The GNSS coordinates, for instance, are used by the UE to know itsposition which can be used to pre-compensate for time and frequency shifts. Further, NR-NTN can utilize open loop timing adjustment procedures for transparent payload NTN architectures, where TA can be partitioned into common TA (e.g., corresponding to the delay on the feeder link ) and UE-specific TA, e.g., corresponding to two-way transmission delay on a service link. To estimate UE specific TA, the UE can utilize serving satellite position (e.g., using information provided by the network to UE) and the UE’s own location, such as based on GNSS. Moreover, since Non- Geostationary Satellite Orbit (NGSO) satellites are moving, the UE may update the timing advance and frequency pre-compensation in a connected mode. Therefore, a UE can rely on a reliable GNSS connection over a period of its connectivity to have NTN access.

[0034] Although GNSS can provide an accurate position and time reference, there can be multiple scenarios where reliable GNSS signals may not be available for a duration of time. For example, GNSS signals can be in outage and / or jammed, or GNSS signals may be spoofed that may result in inaccurate UE position. This can result in denial of NTN connectivity such as based on the UE specific TA being determined from a wrong UE position which may cause errors in uplink (UL) communication. Such scenarios may have an impact on a group of UE in a cell for certain duration. Additionally, there may be occasions when a UE may experience degradation of NTN service due to reduced accuracy in GNSS location estimates, e.g., accuracy reduced to 500 m or 1 km. Such reduced accuracy can result from different causes, e.g., poor GNSS link budget, unavailability of a minimum number of satellites, a position of a UE (e.g., in a pocket, in a bag, etc.), and so forth.

[0035] The degradation and / or denial of NR NTN service (e.g., due to temporary unavailability and / or inaccuracy of GNSS location) to UE in a connected state may have a negative impact on overall NTN system connectivity and / or performance. For instance, to maintain optimal UE connectivity, a network utilizes information in advance about a temporary unavailability of GNSS service and / or when accuracy of GNSS position is below a certain threshold, which may result in erroneous TA calculation, degradation of service, denial of service, etc. Such scenarios may utilize a configuration and reporting mechanism between the next generation (NG) radio access network (RAN) node and the UE and / or information exchange between NG-RAN node and the core network, e.g., LMF.

[0036] As a further issue, when the network determines that there is temporary GNSS outage and / or UE GNSS positioning accuracy has decreased, the network may utilize a signaling procedurefor the calculation of TA, such that there is no denial of service or there is minimum degradation of service at least to the connected UEs.

[0037] Therefore, increasing the robustness of time and frequency synchronization in NR NTN against the temporary unavailability of GNSS is advantageous, such as in a connected state. In this disclosure, techniques and signaling aspects for timing synchronization are disclosed such as when GNSS is temporarily unavailable to one or more UE and while the UE are in connected and / or idle state. This can increase reliability in wireless communications systems and enable non-terrestrial wireless systems to compensate for time variations when GNSS is not available.

[0038] Figure 1 illustrates an example of a wireless communications system 100 in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more NE 102, one or more UE 104, and a core network (CN) 106. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE- Advanced (LTE-A) network. In some other implementations, the wireless communications system 100 may be a NR network, such as a 5G network, a 5G-Advanced (5G-A) network, or a 5G ultrawideband (5G-UWB) network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20. The wireless communications system 100 may support radio access technologies beyond 5G, for example, 6G. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA), etc.

[0039] The one or more NE 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the NE 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a network function, a network entity, a radio access network (RAN), a NodeB, an eNodeB (eNB), a nextgeneration NodeB (gNB), or other suitable terminology. An NE 102 and a UE 104 may communicate via a communication link, which may be a wireless or wired connection. For example, an NE 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface.

[0040] An NE 102 may provide a geographic coverage area for which the NE 102 may support services for one or more UEs 104 within the geographic coverage area. For example, an NE 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or multiple radio access technologies. In some implementations, an NE 102 may be moveable, for example, a satellite associated with a non-terrestrial network (NTN). In some implementations, different geographic coverage areas associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with different NE 102.

[0041] The one or more UEs 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet-of-Things (loT) device, an Internet-of- Everything (loE) device, or machine-type communication (MTC) device, among other examples.

[0042] A UE 104 may be able to support wireless communication directly with other UEs 104 over a communication link. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

[0043] An NE 102 may support communications with the CN 106, or with another NE 102, or both. For example, an NE 102 may interface with other NE 102 or the CN 106 through one or more backhaul links (e.g., SI, N2, N6, or other network interface). In some implementations, the NE 102 may communicate with each other directly. In some other implementations, the NE 102 may communicate with each other indirectly (e.g., via the CN 106). In some implementations, one or more NE 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as a radio heads, smart radio heads, or transmission-reception points (TRPs).

[0044] The CN 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN 106 may be an evolved packet core (EPC), or a 5G core (5GC), which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management functions (AMF)) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signal bearers, etc.) for the one or more UEs 104 served by the one or more NE 102 associated with the CN 106.

[0045] The CN 106 may communicate with a packet data network over one or more backhaul links (e.g., via an SI, N2, N6, or other network interface). The packet data network may include an application server. In some implementations, one or more UEs 104 may communicate with the application server. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the CN 106 via an NE 102. The CN 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server using the established session (e.g., the established PDU session). The PDU session may be an example of a logical connection between the UE 104 and the CN 106 (e.g., one or more network functions of the CN 106).

[0046] In the wireless communications system 100, the NEs 102 and the UEs 104 may use resources of the wireless communications system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communications). In some implementations, the NEs 102 and the UEs 104 may support different resource structures. For example, the NEs 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the NEs 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the NEs 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures). The NEs 102 and the UEs 104 may support various frame structures based on one or more numerologies.

[0047] One or more numerologies may be supported in the wireless communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A firstnumerology (e.g., / r=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g., / r=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., / r=l) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., / r=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., / r=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., / r=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

[0048] A time interval of a resource (e.g., a communication resource) may be organized according to frames (also referred to as radio frames). Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

[0049] Additionally or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. The number of slots in each subframe may also depend on the one or more numerologies supported in the wireless communications system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., / r=0, jU=l , / r=2, / r=3, / r=4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g., quantity) of symbols (e.g., orthogonal frequency division multiplexing (OFDM) symbols). In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing), a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to afirst numerology (e.g., / r=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots.

[0050] In the wireless communications system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communications system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz - 7.125 GHz), FR2 (24.25 GHz - 52.6 GHz), FR3 (7.125 GHz - 24.25 GHz), FR4 (52.6 GHz - 114.25 GHz), FR4a or FR4-1 (52.6 GHz - 71 GHz), and FR5 (114.25 GHz - 300 GHz). In some implementations, the NEs 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the NEs 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g., control information, data). In some implementations, FR2 may be used by the NEs 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

[0051] FR1 may be associated with one or multiple numerologies (e.g., at least three numerologies). For example, FR1 may be associated with a first numerology (e.g., / r=0), which includes 15 kHz subcarrier spacing; a second numerology (e.g., / r=l), which includes 30 kHz subcarrier spacing; and a third numerology (e.g., / r=2), which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g., at least 2 numerologies). For example, FR2 may be associated with a third numerology (e.g., / r=2), which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g., / r=3), which includes 120 kHz subcarrier spacing.

[0052] According to implementations, one or more of the NEs 102 and the UEs 104 are operable to implement various aspects of the techniques described with reference to the present disclosure. For example, a NE 102 (e.g., a base station) transmits to a UE 104 first signaling comprising a connectivity indication indicating whether the UE is to remain in a connected state or an idle state during a GNSS outage. Further, the NE 102 transmits to the UE 104 second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage. The UE 104 can perform uplink time synchronization based at least in part on the first signaling and / or the second signaling.

[0053] With respect to timing adjustments in NTN, time and frequency synchronization in NTN is as follows.

[0054] Downlink (DL) and uplink (UL) are frame aligned at the uplink time synchronization reference point (RP) with an offset given by NTA, offset.

[0055] To accommodate the propagation delay in NTNs, several timing relationships are enhanced by a Common Timing Advance (Common TA) and two offsets K0^setand kmacCommon TA is a configured timing offset that is equal to the roundtrip time (RTT) between the RP and the NTN payload.KoffSet is a configured scheduling offset that is larger or equal to the sum of the service link RTT and the Common TA. kmac isaconfigured offset that is approximately equal to the RTT between the RP and the gNB.

[0056] The scheduling offset K0^setis used to allow the UE sufficient processing time between a downlink reception and an uplink transmission.

[0057] The offset kmacis used to delay the application of a downlink configuration indicated by a MAC CE command on physical downlink shared channel (PDSCH) and in estimation of UE-gNB RTT. The kmacmay be provided by the network when downlink and uplink frame timing are not aligned at gNB. The kmacis also used in the random access procedure, to determine the start time of random access response (RAR) window / MsgB window after a Msgl / MsgA transmission.

[0058] Figure 2 illustrates an example 200 of timing relationship for collocated gNB and NTN Gateway in accordance with aspects of the present disclosure. The example 200 illustrates a service link RTT 202, a feeder link RTT 204, an RP 206, a common TA 208, a kmac210, and a TA time (TTA) 212.

[0059] The network may configure the hybrid automatic repeat request (HARQ) operation as follows:For downlink, HARQ feedback can be enabled or disabled per HARQ process. Disabling HARQ feedback allows scheduling a HARQ process before one HARQ RTT has elapsed since last scheduled.For uplink, HARQ mode (e.g., HARQ mode A or HARQ mode B) can be configured per HARQ process. HARQ mode B allows scheduling a HARQ process before one HARQ RTT has elapsed since last scheduled.

[0060] It should be noted that for the HARQ processes configured with HARQ feedback enabled or disabled, it is up to network implementation to ensure a proper configuration of HARQ feedback (e.g., either all enabled or all disabled) for HARQ processes used by a semi persistent scheduling (SPS) configuration. For the HARQ processes configured with HARQ mode, it is up to network implementation to ensure a proper configuration of HARQ mode (e.g., either all HARQ mode A or all HARQ mode B) for HARQ processes used by a configured grant (CG) configuration.

[0061] With respect to timing advance and frequency pre-compensation, for the serving cell the network broadcasts valid ephemeris information and Common TA parameters. The UE has valid GNSS position as well as ephemeris and Common TA before connecting to an NTN cell. To achieve synchronization, before and during connection to an NTN cell, the UE computes the RTT between UE and the RP based on the GNSS position, the ephemeris, and the Common TA parameters, and autonomously pre-compensate the TTA for the RTT between the UE and the RP.

[0062] The UE computes the frequency Doppler shift of the service link, and autonomously precompensates for it in the uplink transmissions, by considering UE position and the ephemeris. If the UE does not have a valid GNSS position and / or valid ephemeris and Common TA, it does not transmit until both are regained.

[0063] In connected mode, the UE is able to continuously update the Timing Advance and frequency pre-compensation.

[0064] The UE may be configured to report Timing Advance during Random Access procedures or in connected mode. In connected mode, event-triggered reporting of the Timing Advance is supported.

[0065] While the pre-compensation of the instantaneous Doppler shift experienced on the service link is to be performed by the UE, the management of Doppler shift experienced over the feeder link and transponder frequency error is left to the network implementation.

[0066] Transmission timing adjustments procedure for TN and NTN is discussed in the following.

[0067] A UE can be provided a value NTA offSetof a timing advance offset for a serving cell by n-TimingAdvanceOffset for the serving cell. If the UE is not provided n-TimingAdvanceOffset for a serving cell, the UE determines a default value NTA offSetof the timing advance offset for the serving cell.

[0068] If a UE is configured with two UL carriers for a serving cell, a same timing advance offset value NTA offSetapplies to both carriers.

[0069] Upon reception of a timing advance command for a timing advance group (TAG), the UE adjusts uplink timing for one or more of physical uplink control channel (PUSCH), sounding reference signal (SRS), or physical uplink control channel (PUCCH) transmission on all the serving cells in the TAG based on a value NTA offSetthat the UE expects to be same for all the serving cells in the TAG and based on the received timing advance command where the uplink timing for PUSCH / SRS / PUCCH transmissions is the same for all the serving cells in the TAG.

[0070] For a band with synchronous contiguous intra-band Evolved-Universal Terrestrial Radio Access-New Radio (EN) dual connectivity (DC) in a band combination with non-applicable maximum transmit timing difference requirements, if the UE indicates ul- TimingAlignmentEUTRA-NR as 'required' and uplink transmission timing based on timing adjustment indication for a TAG from main cell group (MCG) and a TAG from secondary cell group (SCG) are determined to be different by the UE, the UE adjusts the transmission timing for PUSCH / SRS / PUCCH transmission on all serving cells part of the band with the synchronous contiguous intra-band EN-DC based on timing adjustment indication for a TAG from a serving cell in MCG in the band. The UE is not expected to transmit a PUSCH / SRS / PUCCH in one CG when the PUSCH / SRS / PUCCH is overlapping in time, even partially, with random access preamble transmitted in another CG.

[0071] For a subcarrier spacing (SCS) of 2^ ■ 15 kHz, the timing advance command for a TAG indicates the change of the uplink timing relative to the current uplink timing for the TAG in multiples of 16 ■ 64 ■ Tc / 2ti.

[0072] A timing advance command in case of random access response or in an absolute timing advance command MAC CE, TA, for a TAG indicates NTAvalues by index values of TA= 0, 1, 2, 3846, where an amount of the time alignment for the TAG with SCS of 2^ ■ 15 kHz is NTA= TA■ 16 ■ 64 / 2^. NTAis relative to the SCS of the first uplink transmission from the UE after the reception of the random access response or absolute timing advance command MAC CE.

[0073] In other cases, a timing advance command, TA, for a TAG indicates adjustment of a current NTAvalue, NTA-oid, to the new NTAvalue, NTA new, by index values of TA= 0, 1, 2,..., 63, where for a SCS of 2^ ■ 15 kHz, NTA new= NTA old+ (TA- 31) ■ 16 ■ 64 / 2<

[0074] If a UE has multiple active UL bandwidth parts (BWPs) in a same TAG, including UL BWPs in two UL carriers of a serving cell, the timing advance command value is relative to the largest SCS of the multiple active UL BWPs. The applicable NTA newvalue for an UL bandwidth part (BWP) with lower SCS may be rounded to align with the timing advance granularity for the UL BWP with the lower SCS while satisfying the timing advance accuracy requirements.

[0075] Adjustment of an NTAvalue by a positive or a negative amount indicates advancing or delaying the uplink transmission timing for the TAG by a corresponding amount, respectively.

[0076] For a timing advance command received on uplink slot n and for a transmission other than a PUSCH scheduled by a RAR UL grant or a fallbackRAR UL grant, or a PUCCH with HARQ-ACK information in response to a successRAR, the corresponding adjustment of the uplink transmission timing applies from the beginning of uplink slot n + k + 1+2^ ■ K0^setwhere k =time duration in msec of NAsymbols corresponding to a PDSCH processing time for UE processing capability 1 when additional PDSCH demodulation reference signal (DM-RS) is configured, NT 2is a time duration in msec of N2symbols corresponding to a PUSCH preparation time for UE processing capability 1, NTA maxis the maximum timing advance value in msec that can be provided by a TA command field of 12 bits,number of slots per subframe, TSf is the subframe duration of 1 msec, andKoffset = Kceii, offset ~ KUE, offset, where Kcell offsetis provided by cellSpecificKoffset and KuE.offset isprovided by a Differential Koffset MAC CE command; otherwise, if not respectively provided, KceuOffSet= 0 or KUE offSet= 0. N1and N2are determined with respect to the minimum SCS among the SCSs of all configured UL BWPs for all uplink carriers in the TAG and of all configured DL BWPs for the corresponding downlink carriers. For / r = 0, the UE assumes N1 0= 14 [6, technical specification (TS) 38.214]. Slot ndetermined with respect to the minimum SCS among the SCSs of all configured UL BWPs for all uplink carriers in the TAG. NTA maxis determined with respect to the minimum SCS among the SCSs of all configured UL BWPs for all uplink carriers in the TAG and for all configured initial UL BWPs provided by initialUplinkBWP. The uplink slot n is the last slot among uplink slot(s) overlapping with the slot(s) of PDSCH reception assuming TTA= 0, where the PDSCH provides the timing advance command and TTA.

[0077] If a UE changes an active UL BWP between a time of a timing advance command reception and a time of applying a corresponding adjustment for the uplink transmission timing, the UE determines the timing advance command value based on the SCS of the new active UL BWP. If the UE changes an active UL BWP after applying an adjustment for the uplink transmission timing, the UE assumes a same absolute timing advance command value before and after the active UL BWP change.

[0078] If the received downlink timing changes and is not compensated or is only partly compensated by the uplink timing adjustment without timing advance command, the UE changes NTAaccordingly.

[0079] If two adjacent slots overlap due to a TA command, the latter slot is reduced in duration relative to the former slot. The UE does not change NTAduring an actual transmission time window for a PUSCH or a PUCCH transmission.

[0080] Using higher-layer ephemeris parameters for a serving satellite, if provided, a UE precompensates the two-way transmission delay on the service link based on lV^adj that the UE determines using the serving satellite position and its own position. To pre-compensate the two-way transmission delay between the uplink time synchronization reference point and the servingsatellite, the UE determines[4, TS 38.211] based on one-way propagation delayDelaycommon(t) that the UE determines as:where TACommon, T ACommonDrift, and T ACommonDriftVariantare respectively provided by ta-Common, ta-CommonDrift, and ta-CommonDriftVariant and tepocflis provided by epochTime which is the epoch time of ta-Common, ta-CommonDrift, and ta-CommonDriftVariant.Delaycommon(t) provides a distance at time t between the serving satellite and the uplink time synchronization reference point divided by the speed of light. The uplink time synchronization reference point is the point where DL and UL are frame aligned with an offset given by NTA offSet.With respect to radio resource control (RRC) signaling for TA calculation in NTN, an information element (IE) for NTN configuration, NTN-Config IE, contains the essential parameter information needed for calculation of common TA and User specific.

[0081] Figures 3A and 3B illustrate an example information element 300 in accordance with aspects of the present disclosure. The information element 300 is an example of a NTN-Config IE and includes multiple fields.

[0082] An Ephemerisinfo field provides satellite ephemeris either in format of position and velocity state vector or in format of orbital parameters. This field is excluded when determining changes in system information, e.g., changes to ephemerisinfo should neither result in system information change notifications nor in a modification of valueTag in system information block type 1 (SIBT).

[0083] An epochTime field indicates the epoch time for the NTN assistance information. When explicitly provided through system information block (SIB), or through dedicated signaling, the EpochTime is the starting time of a DL sub-frame, indicated by a system frame number (SFN) and a sub-frame number signaled together with the assistance information. For serving cell, the field sfn indicates the current SFN or the next upcoming SFN after the frame where the message indicating the epochTime is received. For neighbor cell, the sfn indicates the SFN nearest to theframe where the message indicating the epochTime is received. The reference point for epoch time of the serving NTN payload ephemeris and Common TA parameters is the uplink time synchronization reference point. If this field is absent, the epoch time is the end of system information (SI) window where this SIB 19 is scheduled. This field may be mandatory present when provided in dedicated configuration. If this field is absent in ntn-Config provided via NTN- NeighCellConfig the UE uses epoch time of the serving cell, otherwise the field is based on the timing of the serving cell, e.g., the SFN and sub-frame number indicated in this field refers to the SFN and sub-frame of the serving cell. In case of handover or conditional handover, this field is based on the timing of the target cell, e.g., the SFN and sub-frame number indicated in this field refers to the SFN and sub-frame of the target cell. For the target cell the UE considers epoch time, indicated by the SFN and sub-frame number in this field, to be the frame nearest to the frame in which the message indicating the epoch time is received. This field is excluded when determining changes in system information, e.g., changes to epochTime should neither result in system information change notifications nor in a modification of valueTag in SIB1.

[0084] A cellSpecificKoffset field indicates a scheduling offset used for the timing relationships that are modified for NTN. The unit of the field K_offset is number of slots for a given subcarrier spacing of 15 kHz. If the field is absent UE assumes value 0.

[0085] A kmac field indicates a scheduling offset provided by network if downlink and uplink frame timing are not aligned at gNB. It may be needed for UE action and assumption on downlink configuration indicated by a MAC CE command in PDSCH. If the field is absent UE assumes value 0.

[0086] For the reference subcarrier spacing value for the unit of K_mac in FR1, a value of 15 kHz is used. The unit of K_mac is number of slots for a given subcarrier spacing.

[0087] An ntn-PolarizationDL field, if present includes a parameter that indicates polarization information for downlink transmission on service link: including Right hand, Eeft hand circular polarizations (RHCP, EHCP) and Einear polarization.

[0088] An ntn-PolarizationUL field, if present includes a parameter that indicates Polarization information for uplink service link. If not present and ntn-PolarizationDE is present, UE assumes the same polarization for UL and DL.

[0089] An ntn- UlSyncValidityDuration field indicates a validity duration configured by the network for assistance information (e.g., Serving and / or neighbor satellite ephemeris and Common TA parameters) which indicates the maximum time duration (from epochTime) during which the UE can apply assistance information without having acquired new assistance information.

[0090] The unit of ntn-UlSyncValidityDuration is second. Value s5 corresponds to 5 s, value slO indicate 10 s and so on. This parameter applies to both connected and idle mode UEs. If this field is absent in ntn- Config provided via NTN-NeighCellConfig, the UE uses validity duration from the serving cell assistance information. This field is excluded when determining changes in system information, e.g., changes of ntn-UlSyncValidityDuration should neither result in system information change notifications nor in a modification of valueTag in SIB1. ntn- UlSyncValidityDuration is updated when at least one of epochTime, ta-Info, ephemerisinfo is updated.

[0091] A ta-Common field indicates a network-controlled common timing advanced value and it may include any timing offset considered necessary by the network. ta-Common with value of 0 is supported. The granularity of ta-Common is 4.072 x 10A(-3) ps. Values are given in unit of corresponding granularity. This field is excluded when determining changes in system information, e.g., changes of ta-Common should neither result in system information change notifications nor in a modification of valueTag in SIB1.

[0092] A ta-CommonDrift field indicates drift rate of the common TA. The granularity of ta- CommonDrift is 0.2 x 10A(-3) ps / s. Values are given in unit of corresponding granularity. This field is excluded when determining changes in system information, e.g., changes of ta- CommonDrift should neither result in system information change notifications nor in a modification of valueTag in SIB1.

[0093] A ta-CommonDriftVariant field indicates drift rate variation of the common TA. The granularity of ta-CommonDriftVariation is 0.2x10A(-4) ps / sA2. Values are given in unit of corresponding granularity. This field is excluded when determining changes in system information, e.g., changes of ta-CommonDriftVariant should neither result in system information change notifications nor in a modification of valueTag in SIB1.

[0094] A ta-Report field indicates, when this field is included in SIB 19, reporting of timing advanced is enabled during Random Access due to RRC connection establishment or RRC connection resume, and during RRC connection reestablishment. When this field is included in ServingCellConfigCommon within dedicated signaling, it indicates TA reporting is enabled during Random Access due to reconfiguration with sync.

[0095] Accordingly, aspects discussed in this disclosure provide enhancements to TA procedures in scenarios where there is GNSS outage and a UE may have difficulty calculating UE- specific TA for TA adjustment.

[0096] In implementations a network transmits a UE state indication to a connected or idle UE to remain in a connected state or an idle state if a GNSS interruption event occurs. A GNSS interruption event, for instance, represents scenarios where there is GNSS outage and / or GNSS location inaccuracy for more than a specified duration, e.g., a threshold time duration. Such a UE state indication to a UE may be configured by the network in response to GNSS outage and / or when GNSS location inaccuracy occurs and is detected by the network. Further, a UE state indication may be configured using higher layer signaling, dedicated signaling, and / or broadcast signaling.Alternatively or additionally, the network may configure a UE with a UE state indication to remain in a connected state, idle state, or a same current state (e.g., no denial of service) without having GNSS outage information, e.g., as part of NTN SIB. In implementations a UE upon receiving a UE state indication may not disconnect from the network and apply and / or wait for a TA adjustment procedure to be used in a GNSS outage procedure.

[0097] In implementations a UE can be preconfigured with a UE state indication to transition to an idle state upon determination (e.g., by the UE and / or by the network) of a GNSS interruption event. Alternatively or additionally, upon detection of a GNSS interruption event, a UE can indicate the GNSS interruption event to the network and the network may indicate a UE state indication, configure the UE for additional TA adjustment procedure, indicate a maximum duration that the UE may remain in the connected state, and / or combinations thereof.

[0098] In implementations a network may configure a UE with procedures to acquire TA adjustments during a GNSS interruption event. Alternatively or additionally a UE may transmit a request to the network requesting a procedure to acquire TA estimates during a GNSS interruptionevent. For example, in NR NTN, the following formula can be used to determine a timing advance (e.g., referred to as open loop TA procedure):where 1VTAdenotes the TA component based on accumulating “TA commands” received from the network (e.g., by MAC CE command) and is reset to zero whenever there is random access channel (RACH) procedure to acquire TA estimates, whileadj denotes the TA component specific to satellite communications and is determined by the UE based on the UE’s own location and the NTN serving satellite’s ephemeris, thus accuracy of ^TA adjcanbe based on the accuracy of the location information.

[0099] In implementations a network may indicate to a UE to continue using an open loop TA procedure and may indicate to the UE a procedure to use for estimating the UE-specific TA, e.g., timing estimates on service link. In implementations the network may utilize new procedures (e.g., procedures that may not require UE location estimates) to compensate for timing impact on the service link.

[0100] In implementations TA estimates may utilize last known locations. For instance, based on a GNSS interruption event indication from a connected and / or idle UE, the network indicates to the UE to remain in connected mode and update the TA by applying the open loop TA procedure, where the last known GNSS location is used for the calculation of user specific TA, e.g., ( / V-^adj).

[0101] Figure 4 illustrates an example of an information element 400 in accordance with aspects of the present disclosure. The information element 400, for instance, represents a CommonLocationlnfo IE and includes information fields 402 that enable information such as reporting periodicity and location validity duration to be reported. In implementations the network can configure resources to UE to report its GNSS location (e.g., using higher layer signaling CommonLocationlnfo IE such as the information element 400) with periodicity by defining a parameter for periodicity. The parameter, for instance, may indicate periodic, periodic, and / or semi- persistent reporting. The network may also configure a UE to report one or a set of last known UE GNSS locations with a time stamp.

[0102] In implementations, such as to reduce the location reporting signaling, the network may configure a UE to store its GNSS positions for a configured time duration and / or the UE is configured to store its GNSS position for a time duration. The UE, for instance, can report last GNSS location(s) when a GNSS interruption event occurs. A duration for storing GNSS location may be indicated to UE by the network using higher layer and / or dedicated signaling. For example, the UE can continue measuring GNSS locations and performing NR operation simultaneously. When there is a GNSS interruption event, the UE may report the last known GNSS location and / or a set of last known GNSS locations to the network based on a request from network (e.g., receiving CommonLocationlnfo IE) and / or along with GNSS outage report. The UE can include a time stamp for each of the GNSS locations calculated over a time in the report.

[0103] In implementations a UE can be indicated with a validity distance and the UE can report obtained GNSS position information based on various conditions such as when the GNSS position information validity duration (e.g., as indicated by the network and / or as determined by the UE) is elapses, when the UE’s new GNSS position is different from a previously reported GNSS position by at least the indicated distance, when a network indicated reporting interval is passed, and / or combinations thereof.

[0104] In implementations, when a UE is indicated with a reporting interval / duration (e.g., corresponding to reporting occasions of the GNSS position information) and a GNSS position tolerance, the UE can determine based on its own GNSS readings when the actual GNSS position is a distance from a previously reported GNSS position more than the indicated distance tolerance. Upon such determination, the UE can further determine a closest reporting occasion of the configured reporting occasions and report to the network in the determined occasion. The UE may also send a report and / or indicate to the network about the validity duration of a last known GNSS location, and the UE may determine this validity duration based on factors such as its mobility and / or by external information, e.g., through GNSS.

[0105] In implementations the GNSS LTE Positioning Protocol (LPP) IE such as “A-GNSS- ProvideCapabilities” may be used by a gNB to obtain information about the capabilities of a UE regarding GNSS. The information such as whether a UE supports periodic reporting may be used for the network to configure resources for GNSS location reporting.

[0106] In implementations and based on a GNSS interruption event (e.g., based on UE reporting), a last UE GNSS location and / or information about how locations are changing over a period, the network may determine the use of a last known UE location for a TA update. For instance, the network may indicate to the UE to initiate a RACH procedure for TA update and / or may also indicate to the UE to use a last GNSS location for user specific TA, e.g.,adj). The network may specify the GNSS location to be used for this purpose (e.g., in case the UE is not storing the GNSS locations) and / or indicate to the UE to use a last known GNSS location.

[0107] In implementations a network can predict UE locations for a duration of a GNSS interruption event by applying prediction models (e.g., using artificial intelligence (Al) machine learning (ML) and / or Kalman filtering) over the historic data of GNSS locations for a time duration. The network may configure a location to be used for UE specific TA (e.g.,adand / or may configure a set of predicted location estimates of the UE to be used for next TA updates. Further, a time validity for each of the locations may be configured.

[0108] In implementations a UE can estimate its own location (e.g., using prediction and / or AI / ML based models) and use the estimated locations during a GNSS interruption event. For instance, the UE may indicate to the network that the UE has capability to predict its location estimates in case there is a GNSS interruption event. The UE may ask for network permission to use the predicted locations during GNSS outage network. In at least one example, when the network has information that a UE has location estimate prediction capabilities and the UE is trained to do so, the network may configure the UE to use prediction and / or AI / ML based location estimate. This may be done by using higher layer parameter(s) indicating AI / ML and / or prediction-based location estimates are allowed or not allowed for TA estimates. In one implementation, if UE has the capability to predict the location estimate, the UE does not need to indicate the GNSS outage and does not disconnect from the network. When required to update TA using RACH procedure, the UE uses predicted location estimate for user specific TA calculation.

[0109] In implementations location estimates can be used from other procedures. For instance, a network in response to an indication of a GNSS interruption event can initiate a location information procedure to determine whether a location estimate based on other RAT independent procedures (e.g., WLAN, Bluetooth, sensors, etc.) is available. The network, for example, caninitiate a location information procedure by configuring a locationinfo IE to a UE. The UE receiving this request can report to the network whether a location estimate based on another RAT independent procedure is available and may include a time stamp of a location. If the UE report includes a location estimate based on another RAT independent procedure, the network may indicate to the UE to use the location estimate based on other procedures for TA calculation during the GNSS interruption event.

[0110] In one embodiment, the gNB requests to the location server to provide the location estimate of a UE that may be needed for TA calculations. The gNB may include its request message about the reason for requesting location estimate and the time window within which it may need these location estimates. Based on the request message from the gNB, the location server may start a new location estimate procedure (for example, in case a UE is in coverage of three or more satellites) and once it has the location estimate with sufficient accuracy, may provide the location estimates in the response message. Alternatively, the location server may also provide about the recently acquired location estimates. The location server may include a time stamp of the location estimates. Once the gNB has the location estimates, it may configure these location estimates to the UE for TA procedure calculations.

[0111] Implementations described herein enable extension of closed loop TA procedures after expiry of UL synchronization periods. For instance, a network may apply closed loop TA updates (e.g., 1VTA) when UL synchronization time duration or GNSS validity duration is to be expired and there is an expected GNSS interruption event. Such implementations may be applied in scenarios where the network considers that a UE is within acceptable UL synchronization and the UE may remain in acceptable UL synchronization by adjusting 1VTAfor the GNSS interruption event duration. For example the network may indicate to the UE to not to use a RACH procedure for the duration of the GNSS interruption event after the UL synchronization time duration has expired. Further, the UE may additionally be indicated to continue receiving the TA updates (e.g., 1VTA) from the network during a GNSS interruption event and may initiate the RACH procedure after the GNSS interruption event.

[0112] Implementations can enable configuration of a time window for validity of extension of TA procedure. In implementations the network can configure a time window for which an enhanced TA procedure can be valid. For example, where a UE is configured to use a TA procedure inscenarios of a GNSS interruption event by using a last known GNSS position and / or adjusting a TA with MAC-CE TA commands, the UE can be configured with a time window for which the extension of a TA procedure (e.g., without estimating the GNSS location for user specific TA calculation) can be valid. In scenarios where the validity time window has expired and the GNSS interruption event persists, the UE may not use the extended TA procedure and may disconnect from the network.

[0113] Figure 5 illustrates an example of a scenario 500 for an enhanced TA procedure in accordance with aspects of the present disclosure. In implementations a network may extend the time window multiple times by using higher layer and / or dedicated signaling (e.g., MAC-CE) until the network determines that further UL synchronization may not be achieved until new GNSS location estimates are acquired by the UE. Upon expiry of a last timer the UE may disconnect from the network and start performing a connection procedure when it achieves GNSS signals.

[0114] In implementations a UE may not perform GNSS measurements autonomously in an extended TA validity duration (e.g., the time window for TA procedure after the GNSS outage), but the UE may perform GNSS location estimates when either the extended time window expires and / or there is indication from the network to perform GNSS location estimates in this window, e.g., by MAC-CE, downlink control information (DO), etc. In implementations a start duration of the GNSS measurements can be explicitly configured by the network through higher layer signaling and / or dedicated signaling. For example, if a time window of duration T is configured, the network may also configure a ‘X’ time indicating when to start the GNSS measurement. For instance, T+X indicates ‘X’ time after time window duration ‘T’ or T-X means ‘X’ time before time window duration ‘T’ expires.

[0115] In implementations a UE may perform autonomous GNSS measurements during an extended time window and when available, the UE can report to the network information about the availability of GNSS signals and / or location estimates. In response, the network may indicate to the UE to terminate a remaining time period of the extended time window and perform a RACH based TA procedure for TA adjustments. In at least one implementation the open loop TA procedure may be used after the expiry of time window, even if the GNSS signals become available in the extended time window. The scenario 500 includes an example of such a time window 502.

[0116] In implementations an enhanced TA procedure in scenarios of a GNSS interruption event in a UE connected and / or idle state may include:

[0117] (1) A UE checks for its GNSS location before the expiry of UL synchronization validity duration, if GNSS validity duration is going to be expired, or based on an indication from the network to report its GNSS location and / or GNSS interruption event. The UE can report about the GNSS interruption event to the network.

[0118] (2) Based on the report from the UE concerning the GNSS interruption event and indication of a RACH based TA procedure (e.g., in case UL synchronization timer is going to be expired and / or GNSS validity duration is going to be expired), the network can indicate to the UE to remain in connected / idle mode and provide the UE one of the following procedures to facilitate the calculation of user specific TA (i.e.,adand / or indicate to not apply a RACH procedure for TA calculation. a. The network can indicate to the UE to use the last known GNSS location for UE specific TA calculation. The network may determine a procedure where a UE reports its location with periodicity and with or without a location validity duration.Alternatively or additionally the UE may or may not be configured to store its GNSS location or locations for a period. b. The network may use prediction and / or AI / ML based procedures to predict a UE location estimate during the the GNSS interruption event. The network may determine a signaling procedure to acquire parameters for prediction of location estimates. The network may indicate to the UE that which location estimates may be used by UE to calculate the user specific TA. Alternatively or additionally, based on UE capabilities, the UE may predict the location estimates and use these location estimates for user specific TA calculation. c. The network may indicate to the UE that a previous TA is valid and not to apply a RACH based TA procedure for TA updates. The network can configure a validity duration beyond the already configured validity duration (e.g., UL synchronization validity duration). The network may continue adjusting the TA using MAC-CE TA command ( / VTA) during a next validity duration.

[0119] (3) The network may add a timer (e.g., a validity duration) to apply one or combination of above methods and indicate this timer to UE. The UE may repeat previous steps if this timer expires and there is still a GNSS interruption event. The network may also indicate to the UE during the above mentioned configuration steps about what to do when a timer for enhanced TA procedure expires during the GNSS interruption event, e.g., disconnect and / or receive a new procedure and / or extension.

[0120] Implementations also provide for TA calculations based on RTT. For instance, a network can adjust a service link TA with the RTT of the service link, where RTT of the service link may be calculated by the NG-RAN node (gNB) and / or by the core network (e.g., LMF).

[0121] Implementations also provide for TA calculation based on uplink reference signal. For instance, a network can apply a TA adjustment based on the time difference it receives an SRS signal and the time the SRS signal is transmitted by the UE, such as in scenarios where a UE is in a connected / idle mode. The network may configure resources when to transmit the SRS and activate the SRS transmission by MAC-CE. Based on the SRS reception, the network may calculate the relative time when the SRS are transmitted to when the SRS is received. This relative time may further be applied for TA adjustment, such as by using MAC-CE TA command and / or by other dedicated signaling.

[0122] In implementations, when a GNSS interruption event occurs, a UE can apply an obtained position for determine UE specific TA parameters, such as based on a history of obtained GNSS position information, a history of the RAT dependent positioning information, RAT independent sensor measurements (e.g., pressure sensor, motion sensor, etc.), and so on. The UE can then predict estimates of the UE position (e.g., during a GNSS interruption event) and applies the predicted position(s) for determining UE specific TA parameters.

[0123] In implementations a UE can inform a network of the GNSS interruption event and / or the UE specific TA adjustment can be generated based on a predictive computational model and / or the description of the computational model applied, e.g., available input data, AI / ML model type, etc.

[0124] In implementations, when a UE maintains RRC connected state during a GNSS interruption event and utilizes its own predictive models for computation of UE-specific TAparameters, the UE may determine that the prediction accuracy does not meet a reliability threshold and thus can request assistance from the network while maintaining RRC connected state. The UE determination of a need for additional network assistance may be determined by the UE based on indicated criteria by the network, e.g., an estimated error threshold.

[0125] In implementations the network can determine that the UE is to perform additional TA adjustment procedures while in a connected state. In one such example, the network determines the need for TA adjustment of the UE based on observing UL data, UL control, and / or RS transmitted by the UE. Further, the network may configure the UE for one or more UL transmissions (e.g., one or more UL SRS) and / or configure the UE with a TA adjustment, e.g., including an indicated constant shift of the UL timing, an indicated constant shift of the first-order slope of UL timing drift, an indicated constant shift of the second-order slope of UL timing drift, or combinations thereof.

[0126] Figure 6 illustrates an example of a UE 600 in accordance with aspects of the present disclosure. The UE 600 may include a processor 602, a memory 604, a controller 606, and a transceiver 608. The processor 602, the memory 604, the controller 606, or the transceiver 608, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

[0127] The processor 602, the memory 604, the controller 606, or the transceiver 608, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

[0128] The processor 602 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof). In some implementations, the processor 602 may be configured to operate the memory 604. In some other implementations, the memory 604 may be integrated into the processor 602. The processor 602 maybe configured to execute computer-readable instructions stored in the memory 604 to cause the UE 600 to perform various functions of the present disclosure.

[0129] The memory 604 may include volatile or non-volatile memory. The memory 604 may store computer-readable, computer-executable code including instructions when executed by the processor 602 cause the UE 600 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as the memory 604 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0130] In some implementations, the processor 602 and the memory 604 coupled with the processor 602 may be configured to cause the UE 600 to perform one or more of the functions described herein (e.g., executing, by the processor 602, instructions stored in the memory 604). For example, the processor 602 may support wireless communication at the UE 600 in accordance with examples as disclosed herein. The UE 600 may be configured to or operable to support a means for receiving first signaling including a connectivity indication indicating whether to remain in a connected state or an idle state during a GNSS outage; receiving second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage; and performing uplink time synchronization based at least in part on the first signaling and the second signaling.

[0131] Additionally, the UE 600 may be configured to support any one or combination of where the GNSS outage includes at least one of: a time period during which the UE does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved; receiving third signaling including an indication to report one or more GNSS locations before the GNSS outage; performing, based at least in part on the thirdsignaling, one or more GNSS location estimates based at least in part on a first periodicity; and transmitting, based at least in part on a second periodicity, a report including the one or more GNSS location estimates; the report includes a time stamp; the one or more GNSS location estimates include at least one GNSS location estimate prior to the GNSS outage; transmitting the report in response to the GNSS outage; transmitting a report including one or more parameters for selecting a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for one or more reported GNSS location estimates; the validity distance defines a distance at which a new GNSS position of the UE is different from a previous GNSS position of the UE.

[0132] Additionally, the UE 600 may be configured to support any one or combination of where the second signaling includes a location estimate for timing advance calculation; receiving third signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; applying the prediction model to predict at least one location estimate; and transmitting a report including the at least one location estimate; receiving fourth signaling including a reporting configuration, the reporting configuration includes UE capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; the report includes the at least one location estimate with a time stamp indicating a future time value for using the at least one location estimate; receiving third signaling including configuration information for estimating a location of the UE based on one or more radio access technology (RAT)-independent techniques that include one or more of WLAN, Bluetooth, or sensors; estimating a location of the UE based at least in part on the one or more RAT-independent techniques; and applying the estimated location of the UE for calculation of UE-specific timing advance.

[0133] Additionally, the UE 600 may be configured to support any one or combination of where the second signaling includes an indication to adjust a validity duration for uplink time synchronization (e.g., extend the validity duration with a time value); the second signaling includes a MAC CE; the second signaling includes multiple configurations for adjusting (e.g., extending) multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS locationestimates during the adjusted validity duration; performing GNSS measurement autonomously during the adjusted validity duration; and reporting GNSS availability information during the adjusted validity duration.

[0134] Additionally, or alternatively, the UE 600 may support functionality to receive first signaling including a connectivity indication indicating whether to remain in a connected state or an idle state during a GNSS outage; receive second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage; and perform uplink time synchronization based at least in part on the first signaling and the second signaling.

[0135] Additionally, the UE 600 may be configured to support any one or combination of where the GNSS outage includes at least one of: a time period during which the UE does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved; the at least one processor is configured to cause the UE to: receive, , third signaling including an indication to report one or more GNSS locations before the GNSS outage; perform, based at least in part on the third signaling, one or more GNSS location estimates based at least in part on a first periodicity; and transmit, based at least in part on a second periodicity, a report including the one or more GNSS location estimates; the report includes a time stamp; the one or more GNSS location estimates include at least one GNSS location estimate prior to the GNSS outage; the at least one processor is configured to cause the UE to transmit the report in response to the GNSS outage.

[0136] Additionally, the UE 600 may be configured to support any one or combination of where the at least one processor is configured to cause the UE to transmit a report including one or more parameters for selecting a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for one or more reported GNSS location estimates; the validity distance defines a distance at which a new GNSS position of the UE is different from a previous GNSS position of the UE; the second signaling includes a location estimate for timing advance calculation; the at least one processor is configured to cause the UE to: receive third signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; apply the prediction model to predict at least one locationestimate; and transmit a report including the at least one location estimate; the at least one processor is configured to cause the UE to receive fourth signaling including a reporting configuration, the reporting configuration includes UE capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; the report includes the at least one location estimate with a time stamp indicating a future time value for using the at least one location estimate.

[0137] Additionally, the UE 600 may be configured to support any one or combination of where the at least one processor is configured to cause the UE to: receive third signaling including configuration information for estimating a location of the UE based on one or more radio access technology (RAT)-independent techniques that include one or more of WLAN, Bluetooth, or sensors; estimate a location of the UE based at least in part on the one or more RAT-independent techniques; and apply the estimated location of the UE for calculation of UE-specific timing advance; the second signaling includes an indication to adjust a validity duration for uplink time synchronization; the second signaling includes a MAC CE; the second signaling includes multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS location estimates during the adjusted validity duration; the at least one processor is configured to cause the UE to: perform GNSS measurement autonomously during the adjusted validity duration; and report GNSS availability information during the adjusted validity duration.

[0138] The controller 606 may manage input and output signals for the UE 600. The controller 606 may also manage peripherals not integrated into the UE 600. In some implementations, the controller 606 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 606 may be implemented as part of the processor 602.

[0139] In some implementations, the UE 600 may include at least one transceiver 608. In some other implementations, the UE 600 may have more than one transceiver 608. The transceiver 608 may represent a wireless transceiver. The transceiver 608 may include one or more receiver chains 610, one or more transmitter chains 612, or a combination thereof.

[0140] A receiver chain 610 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 610 may include one or more antennas to receive a signal over the air or wireless medium. The receiver chain 610 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiver chain 610 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 610 may include at least one decoder for decoding the demodulated signal to receive the transmitted data.

[0141] A transmitter chain 612 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 612 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmitter chain 612 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 612 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0142] Figure 7 illustrates an example of a processor 700 in accordance with aspects of the present disclosure. The processor 700 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 700 may include a controller 702 configured to perform various operations in accordance with examples as described herein. The processor 700 may optionally include at least one memory 704, which may be, for example, an L1 / L2 / L3 cache. Additionally, or alternatively, the processor 700 may optionally include one or more arithmetic-logic units (ALUs) 706. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0143] The processor 700 may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipsetmay include one or more cores, one or more caches (e.g., memory local to or included in the processor chipset (e.g., the processor 700) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM), and others).

[0144] The controller 702 may be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 700 to cause the processor 700 to support various operations in accordance with examples as described herein. For example, the controller 702 may operate as a control unit of the processor 700, generating control signals that manage the operation of various components of the processor 700. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

[0145] The controller 702 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from the memory 704 and determine subsequent instruction(s) to be executed to cause the processor 700 to support various operations in accordance with examples as described herein. The controller 702 may be configured to track memory addresses of instructions associated with the memory 704. The controller 702 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 702 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 700 to cause the processor 700 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 702 may be configured to manage flow of data within the processor 700. The controller 702 may be configured to control transfer of data between registers, ALUs 706, and other functional units of the processor 700.

[0146] The memory 704 may include one or more caches (e.g., memory local to or included in the processor 700 or other memory, such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 704 may reside within or on a processor chipset (e.g., local to the processor 700). In some other implementations, the memory 704 may reside external to the processor chipset (e.g., remote to the processor 700).

[0147] The memory 704 may store computer-readable, computer-executable code including instructions that, when executed by the processor 700, cause the processor 700 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. The controller 702 and / or the processor 700 may be configured to execute computer-readable instructions stored in the memory 704 to cause the processor 700 to perform various functions. For example, the processor 700 and / or the controller 702 may be coupled with or to the memory 704, the processor 700, and the controller 702, and may be configured to perform various functions described herein. In some examples, the processor 700 may include multiple processors and the memory 704 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein.

[0148] The one or more ALUs 706 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 706 may reside within or on a processor chipset (e.g., the processor 700). In some other implementations, the one or more ALUs 706 may reside external to the processor chipset (e.g., the processor 700). One or more ALUs 706 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 706 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 706 may be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 706 may support logical operations such as AND, OR, exclusive-OR (XOR), not-OR (NOR), and not-AND (NAND), enabling the one or more ALUs 706 to handle conditional operations, comparisons, and bitwise operations.

[0149] The processor 700 may support wireless communication in accordance with examples as disclosed herein. The processor 700 may be configured to or operable to receive first signaling including a connectivity indication indicating whether to remain in a connected state or an idle state during a GNSS outage; receive second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage; and perform uplink time synchronization based at least in part on the first signaling and the second signaling.

[0150] Additionally, the processor 700 may be configured to support any one or combination of where the GNSS outage includes at least one of: a time period during which a user equipment (UE) does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved; receive third signaling including an indication to report one or more GNSS locations before the GNSS outage; perform, based at least in part on the third signaling, one or more GNSS location estimates based at least in part on a first periodicity; and transmit, based at least in part on a second periodicity, a report including the one or more GNSS location estimates; the report includes a time stamp; the one or more GNSS location estimates include at least one GNSS location estimate prior to the GNSS outage; the processor can transmit the report in response to the GNSS outage.

[0151] Additionally, the processor 700 may be configured to support any one or combination of to transmit a report including one or more parameters for selecting a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for one or more reported GNSS location estimates; the validity distance defines a distance at which a new GNSS position of a user equipment (UE) is different from a previous GNSS position of the UE; the second signaling includes a location estimate for timing advance calculation; to receive third signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; apply the prediction model to predict at least one location estimate; and transmit a report including the at least one location estimate; to receive fourth signaling including a reporting configuration, the reporting configuration includes user equipment (UE) capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; the report includes the at least one location estimate with a time stamp indicating a future time value for using the at least one location estimate.

[0152] Additionally, the processor 700 may be configured to support any one or combination of to receive third signaling including configuration information for estimating a location of a user equipment (UE) based on one or more radio access technology (RAT)-independent techniques that include one or more of WLAN, Bluetooth, or sensors; estimate a location of the UE based at least inpart on the one or more RAT-independent techniques; and apply the estimated location of the UE for calculation of UE-specific timing advance; the second signaling includes an indication to adjust a validity duration for uplink time synchronization; the second signaling includes a MAC CE; the second signaling includes multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS location estimates during the adjusted validity duration; to perform GNSS measurement autonomously during the adjusted validity duration; and report GNSS availability information during the adjusted validity duration.

[0153] Figure 8 illustrates an example of a NE 800 in accordance with aspects of the present disclosure. The NE 800 may include a processor 802, a memory 804, a controller 806, and a transceiver 808. The processor 802, the memory 804, the controller 806, or the transceiver 808, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

[0154] The processor 802, the memory 804, the controller 806, or the transceiver 808, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

[0155] The processor 802 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof). In some implementations, the processor 802 may be configured to operate the memory 804. In some other implementations, the memory 804 may be integrated into the processor 802. The processor 802 may be configured to execute computer-readable instructions stored in the memory 804 to cause the NE 800 to perform various functions of the present disclosure.

[0156] The memory 804 may include volatile or non-volatile memory. The memory 804 may store computer-readable, computer-executable code including instructions when executed by the processor 802 cause the NE 800 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as the memory 804 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0157] In some implementations, the processor 802 and the memory 804 coupled with the processor 802 may be configured to cause the NE 800 to perform one or more of the functions described herein (e.g., executing, by the processor 802, instructions stored in the memory 804). For example, the processor 802 may support wireless communication at the NE 800 in accordance with examples as disclosed herein. The NE 800 may be configured to or operable to support a means for transmitting first signaling including a connectivity indication indicating whether a user equipment (UE) is to remain in a connected state or an idle state during a GNSS outage; and transmitting second signaling including a timing advance adjustment procedure to apply for time synchronization during the GNSS outage.

[0158] Additionally, the NE 800 may be configured to support any one or combination of where the GNSS outage includes at least one of: a time period during which the UE does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved; transmitting third signaling including an indication to report one or more GNSS locations before the GNSS outage; and receiving a report including one or more GNSS location estimates; receiving a report including one or more parameters for selecting a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for one or more reported GNSS location estimates; the validity distance defines a distance at which a new GNSS position of the UE is different from a previous GNSS position of the UE; the second signaling includes a location estimate for timing advance calculation; transmittingthird signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; and receiving a report including the at least one location estimate.

[0159] Additionally, the NE 800 may be configured to support any one or combination of transmitting fourth signaling including a reporting configuration, the reporting configuration includes UE capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; transmitting third signaling including configuration information for estimating a location of the UE based on one or more radio access technology (RAT)-independent techniques that include one or more of WLAN, Bluetooth, or sensors; the second signaling includes an indication to adjust a validity duration for uplink time synchronization; the second signaling includes a MAC CE; the second signaling includes multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS location estimates during the adjusted validity duration; receiving a report including GNSS availability information during the adjusted validity duration.

[0160] Additionally, or alternatively, the NE 800 may support functionality to transmit first signaling including a connectivity indication indicating whether a user equipment (UE) is to remain in a connected state or an idle state during a GNSS outage; and transmit second signaling including a timing advance adjustment procedure to apply for time synchronization during the GNSS outage.

[0161] Additionally, the NE 800 may be configured to support any one or combination of where the GNSS outage includes at least one of: a time period during which the UE does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved; to transmit third signaling including an indication to report one or more GNSS locations before the GNSS outage; and receive a report including the one or more GNSS location estimates; to receive a report including one or more parameters for selecting a time synchronization procedure, the one or more parameters include at least one of a validity duration or a validity distance for one or more reported GNSS location estimates; the validity distance defines adistance at which a new GNSS position of the UE is different from a previous GNSS position of the UE; the second signaling includes a location estimate for timing advance calculation .

[0162] Additionally, the NE 800 may be configured to support any one or combination of to transmit third signaling including an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; and receive a report including the at least one location estimate; to transmit fourth signaling including a reporting configuration, the reporting configuration includes UE capability information including one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates; to transmit third signaling including configuration information for estimating a location of the UE based on one or more radio access technology (RAT)-independent techniques that include one or more of WLAN, Bluetooth, or sensors; the second signaling includes an indication to adjust a validity duration for uplink time synchronization; the second signaling includes a MAC CE; the second signaling includes multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; the second signaling includes an indication to not apply an open loop timing advance calculation during the adjusted validity duration; the second signaling includes an indication of when to calculate GNSS location estimates during the adjusted validity duration; to receive a report including GNSS availability information during the adjusted validity duration.

[0163] The controller 806 may manage input and output signals for the NE 800. The controller 806 may also manage peripherals not integrated into the NE 800. In some implementations, the controller 806 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 806 may be implemented as part of the processor 802.

[0164] In some implementations, the NE 800 may include at least one transceiver 808. In some other implementations, the NE 800 may have more than one transceiver 808. The transceiver 808 may represent a wireless transceiver. The transceiver 808 may include one or more receiver chains 810, one or more transmitter chains 812, or a combination thereof.

[0165] A receiver chain 810 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 810 may include one ormore antennas to receive a signal over the air or wireless medium. The receiver chain 810 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiver chain 810 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 810 may include at least one decoder for decoding the demodulated signal to receive the transmitted data.

[0166] A transmitter chain 812 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 812 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like PSK or QAM. The transmitter chain 812 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 812 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0167] Figure 9 illustrates a flowchart of a method 900 in accordance with aspects of the present disclosure. The operations of the method may be implemented by a UE as described herein. In some implementations, the UE may execute a set of instructions to control the function elements of the UE to perform the described functions. It should be noted that the method described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0168] At 902, the method may include receiving first signaling comprising a connectivity indication indicating whether to remain in a connected state or an idle state during a GNSS outage. The operations of 902 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 902 may be performed by a UE as described with reference to Figure 6.

[0169] At 904, the method may include receiving second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage. The operations of904 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 904 may be performed by a UE as described with reference to Figure 6.

[0170] At 906, the method may include performing uplink time synchronization based at least in part on the first signaling and the second signaling. The operations of 906 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 906 may be performed a UE as described with reference to Figure 6.

[0171] Figure 10 illustrates a flowchart of a method 1000 in accordance with aspects of the present disclosure. The operations of the method may be implemented by a NE as described herein. In some implementations, the NE may execute a set of instructions to control the function elements of the NE to perform the described functions. It should be noted that the method described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0172] At 1002, the method may include transmitting first signaling comprising a connectivity indication indicating whether a UE is to remain in a connected state or an idle state during a GNSS outage. The operations of 1002 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1002 may be performed by a NE as described with reference to Figure 8.

[0173] At 1004, the method may include transmitting second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage. The operations of 1004 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1004 may be performed by a NE as described with reference to Figure 8.

[0174] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

CLAIMSWhat is claimed is:

1. A user equipment (UE) for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: receive first signaling comprising a connectivity indication indicating whether to remain in a connected state or an idle state during a global navigation satellite system (GNSS) outage; receive second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage; and perform uplink time synchronization based at least in part on the first signaling and the second signaling.

2. The UE of claim 1, wherein the GNSS outage comprises at least one of: a time period during which the UE does not have GNSS connectivity; a time period during which the UE does not find GNSS connectivity; a time period during which the UE does not have a minimum number of GNSS satellites in view for estimating a UE location estimate; or a time period during which a minimum accuracy of GNSS-based positioning may not be achieved.

3. The UE of claim 1 , wherein the at least one processor is configured to cause the UE to: receive, third signaling comprising an indication to report one or more GNSS locations before the GNSS outage; perform, based at least in part on the third signaling, one or more GNSS location estimates based at least in part on a first periodicity; andtransmit, based at least in part on a second periodicity, a report comprising the one or more GNSS location estimates.

4. The UE of claim 3, wherein the report comprises a time stamp.

5. The UE of claim 3, wherein the one or more GNSS location estimates comprise at least one GNSS location estimate prior to the GNSS outage.

6. The UE of claim 3, wherein the at least one processor is configured to cause the UE to transmit the report in response to the GNSS outage.

7. The UE of claim 1 , wherein the at least one processor is configured to cause the UE to transmit a report comprising one or more parameters for selecting a time synchronization procedure, wherein the one or more parameters comprise at least one of a validity duration or a validity distance for one or more reported GNSS location estimates.

8. The UE of claim 7, wherein the validity distance defines a distance at which a new GNSS position of the UE is different from a previous GNSS position of the UE.

9. The UE of claim 1, wherein the second signaling comprises a location estimate for timing advance calculation.

10. The UE of claim 1 , wherein the at least one processor is configured to cause the UE to: receive third signaling comprising an indication to apply a prediction model to predict at least one location estimate of the GNSS outage; apply the prediction model to predict at least one location estimate; and transmit a report comprising the at least one location estimate.

11. The UE of claim 10, wherein the at least one processor is configured to cause the UE to receive fourth signaling comprising a reporting configuration, wherein the reporting configurationcomprises UE capability information comprising one or more of a UE capability to apply the prediction model, one or more types of prediction models, or a UE capability to predict a number of location estimates.

12. The UE of claim 10, wherein the report comprises the at least one location estimate with a time stamp indicating a future time value for using the at least one location estimate.

13. The UE of claim 1 , wherein the at least one processor is configured to cause the UE to: receive third signaling comprising configuration information for estimating a location of the UE based on one or more radio access technology (RAT)-independent techniques that comprise one or more of wireless local access network (WLAN), Bluetooth, or sensors; estimate a location of the UE based at least in part on the one or more RAT-independent techniques; and apply the estimated location of the UE for calculation of UE-specific timing advance.

14. The UE of claim 1, wherein the second signaling comprises an indication to adjust a validity duration for uplink time synchronization.

15. The UE of claim 14, wherein the second signaling comprises a medium access control (MAC) control element (CE).

16. The UE of claim 14, wherein the second signaling comprises one or more of: multiple configurations for adjusting multiple uplink time synchronization windows with multiple times values; an indication to not apply an open loop timing advance calculation during the adjusted validity duration; or an indication of when to calculate GNSS location estimates during the adjusted validity duration.

17. The UE of claim 14, wherein the at least one processor is configured to cause the UE to: perform GNSS measurement autonomously during the adjusted validity duration; and report GNSS availability information during the adjusted validity duration.

18. A processor for wireless communication, comprising: at least one controller coupled with at least one memory and configured to cause the processor to: receive first signaling comprising a connectivity indication indicating whether to remain in a connected state or an idle state during a global navigation satellite system (GNSS) outage; receive second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage; and perform uplink time synchronization based at least in part on the first signaling and the second signaling.

19. A network entity for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the network entity to: transmit first signaling comprising a connectivity indication indicating whether a user equipment (UE) is to remain in a connected state or an idle state during a global navigation satellite system (GNSS) outage; and transmit second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage.

20. A method performed by a user equipment (UE), comprising: receiving first signaling comprising a connectivity indication indicating whether to remain in a connected state or an idle state during a global navigation satellite system (GNSS) outage; receiving second signaling comprising a timing advance adjustment procedure to apply for time synchronization during the GNSS outage; andperforming uplink time synchronization based at least in part on the first signaling and the second signaling.

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