Timing advance (TA) maintenance in non-terrestrial network (NTN)

Abstract

The invention relates to timing advance (TA) maintenance in a non-terrestrial network (NTN). The techniques discussed herein may better ensure appropriate timing and synchronization of transmissions within wireless communication networks, including terrestrial and non-terrestrial networks (NTNs). A user equipment (UE) may maintain (e.g., determine and update, on an ongoing basis) a timing advance (TA) value that the UE may apply to uplink (UL) transmissions to account for propagation delays between the UE, the NTN, and the terrestrial network, including changes in propagation delays. The TA maintenance may be based on network broadcasts, random access channel (RACH) procedures, control messages, timing drift rates (e.g., of the UE or NTN satellite), beam switching, and the like.

Description

[0001] Related application citations

[0002] This application is a divisional application of the invention patent application with international application number PCT / CN2020 / 122988, international application date October 22, 2020, date of entry into the Chinese national phase April 21, 2023, Chinese national application number 202080106566.6, and invention name “Timing Advance (TA) Maintenance in Non-Terrestrial Networks (NTN)”. Technical Field

[0003] The present disclosure relates to wireless communication networks, and more particularly to techniques for maintaining timing and synchronization within non-terrestrial networks (NTNs). Other aspects and techniques are also described. Background Art

[0004] As the number of mobile devices and demand for mobile data traffic within wireless networks continues to increase, system requirements and architectures are changing to better address current and anticipated needs. For example, some wireless communication networks (e.g., fifth-generation (5G) or new radio (NR) networks) may be developed to include a non-terrestrial network (NTN) with one or more satellites. In such scenarios, satellites may serve as transparent network nodes connecting user equipment (UE) with the ground-based portion of the network, such as base stations and the core network (CN). BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present disclosure will be easily understood and implemented through the detailed description and accompanying drawings. The same reference numerals may designate the same features and structural elements. The drawings and corresponding descriptions are provided as non-limiting examples of aspects, implementations, etc. of the present disclosure, and references to "one" or "an" aspect, implementation, etc. may not necessarily refer to the same aspect, implementation, etc., and may mean at least one, one or more, etc.

[0006] Figure 1 is a diagram of an example network according to one or more implementations described herein.

[0007] Figure 2 is a diagram of exemplary dynamics associated with timing advance (TA) maintenance in a non-terrestrial network (NTN).

[0008] Figure 3 is a flow chart of an exemplary process for TA maintenance.

[0009] Figure 4 This is a table showing examples of changes in TA values ​​during TA maintenance.

[0010] Figures 5 to 7 is a sequence diagram of an exemplary process of TA maintenance.

[0011] Figure 8 is a diagram illustrating an example of TA maintenance during beam switching.

[0012] Figure 9 is a diagram of an example of components of a device according to one or more implementations described herein.

[0013] Figure 10 is a diagram of an exemplary interface of baseband circuitry according to one or more implementations described herein. DETAILED DESCRIPTION

[0014] The following detailed description refers to the accompanying drawings. The same reference numerals in different drawings may identify the same or similar features, elements, operations, etc. In addition, the present disclosure is not limited to the following description, as other specific implementations may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure.

[0015] Mobile communication networks may include one or more types and / or generations of wireless communication networks, such as 4th generation (4G) networks, 5th generation (5G) or new radio (NR) networks, etc. Such networks may include user equipment (UE) and base stations that communicate with each other wirelessly. Such networks may also include or be connected to non-terrestrial networks (NTNs), so that terrestrial network devices (e.g., user equipment (UE), base stations, etc.) can communicate with each other via non-terrestrial devices (e.g., low earth orbit (LEO) satellites, geosynchronous orbit (GEO) satellites, etc.).

[0016] In this capacity, the satellite can operate transparently by relaying communications between the UE and the base station without demodulation or remodulation. Alternatively, the satellite can operate regeneratively by using onboard processing capabilities to, for example, demodulate uplink (UL) signals between the UE and the base station and remodulate downlink (DL) signals between the UE and the base station. In some implementations, the satellite may be capable of operating as a base station or another type of network access point (AP) for a wireless terrestrial network. Therefore, in a given scenario, the functions mentioned herein as being performed by the base station may also or alternatively be performed by the satellite.

[0017] Enabling UEs to connect to wireless terrestrial networks via satellites can enhance network connectivity and reliability by increasing the number of APs available to UEs for communicating with the network. This can also increase the collective coverage area of the network, as the transmission capabilities (e.g., coverage area, coverage zone, etc.) of a satellite can be greater than that of a terrestrial base station. This increase in network coverage can result in scenarios where UEs connected to a base station via a satellite or connected to a satellite operating as a base station can be geographically closer to the base station than UEs directly connected to a terrestrial base station (e.g., UEs within the coverage area of the base station), and thus can have different transmission timing constraints (e.g., lower propagation delay). Additionally, UE transmission propagation delay can be affected at least in part by satellite type, as the maximum differential delay for a GEO satellite can be 10.3 microseconds (pm), while the maximum differential delay for a LEO can be 3.12 pm and 3.18 pm, depending on the LEO altitude.

[0018] Propagation delay as used herein can be based on UL transmissions between a UE and a specified reference point (RP) (e.g., a base station, a satellite, etc.), which can include a network device in which timing alignment of UL and DL frames can be observed. For example, the RP can operate by measuring time differences between physical uplink shared channel (PUSCH) communications, physical uplink control channel (PUCCH) communications, and sounding reference signal (SRS) communications, and corresponding subframes to measure or determine alignment and / or derive appropriate TA value adjustments. In scenarios involving transparent satellites, the RP used to determine propagation delay can be a base station. In contrast, in scenarios involving regenerative satellites, the RP used to determine propagation delay can be a satellite. In such scenarios, the propagation delay between the regenerative satellite and the base station can be monitored, detected, and resolved by the network (e.g., not involving the UE).

[0019] A wireless communication network may implement techniques to help ensure proper timing and synchronization of wireless transmissions. An example of such a technique may include using a timing advance (TA) value for uplink (UL) transmissions, whereby a UE can account for signal propagation delays by modifying the UL transmission time based on the TA value so that the signal arrives at the network at the appropriate time (e.g., according to the frame structure implemented by a base station, satellite, etc.). For an initial uplink transmission (e.g., for a random access channel (RACH) procedure), the UE may determine the initial TA value based on one or more of a UE-specific differential TA (or UE-specific TA) and / or a common TA. For UEs communicating via satellite, the UE-specific differential TA may include a value corresponding to the signal propagation delay between the UE and the satellite, and the UE may determine the UE-specific TA based on information such as the UE's location, the UE's Global Navigation Satellite System (GNSS) capabilities, satellite ephemeris information, and timestamp information. The common TA may include a value corresponding to the signal propagation delay between the satellite and the base station, which may be determined by the network on a per-satellite or coverage area basis and / or broadcast to UEs in the coverage area.

[0020] Because the distance and propagation delay between a UE and a satellite and / or base station can vary over time, the techniques described herein enable appropriate maintenance (e.g., modification and updating) of the TA value to better ensure appropriate arrival times for UL transmissions. For example, after determining the initial TA value described above, the UE may receive a message (e.g., a random access channel (RACH) response (RAR), a medium access control (MAC) control element (CE), etc.) that causes the UE to update the TA value based on the message. Additionally or alternatively, the network may transmit a new or updated common TA and / or UE-specific TA, which the UE may use to update the TA value for subsequent UL transmissions.

[0021] The techniques described herein also enable a UE to update a TA value based on a timing drift rate value, which may correspond to a rate of change in signal propagation delay based on factors such as the speed and trajectory of the UE and / or satellite. For example, the UE may determine a timing drift rate to apply to the TA value based on a common timing drift rate and / or a dedicated (or UE-specific) timing drift rate, which may be received from the network (e.g., in a MAC CE) or determined by the UE. The common timing drift rate may be broadcast to UEs in a satellite coverage area or coverage zone and may correspond to a change in the distance between the satellite and the base station given the speed and trajectory of the satellite. The UE-specific timing drift rate may correspond to a change in the distance between the UE and the satellite given the relative speed and trajectory of the satellite and the UE. The UE may update the TA value based on the timing drift rate and a duration, such as a duration measured since the most recent TA value update or the most recent UL transmission. Additionally or alternatively, the UE may update the TA value based on a timing trigger (e.g., every UL transmission, at predetermined intervals, continuously (e.g., based on real-time)), in response to a newly received common TA, a UE-specific TA, in response to a message with instructions for updating the TA, etc.

[0022] The techniques described herein also include TA maintenance during beam switching. For example, a UE may update the TA value during beam switching because a TA value that is appropriate for one satellite may not be appropriate for another. In some implementations, the UE may update the TA during beam switching based on instructions received from the network (e.g., MAC CE, Transmission Control Indicator (TCI) status, etc.). TA information (e.g., common TA, UE-specific TA, TA command, etc.) can be an absolute value that the UE can use to replace the old TA value or a differential (or relative) value that the UE can use to modify the old TA value. Similarly, timing drift rate information (e.g., common timing drift rate, UE-specific timing drift rate, etc.) can be an absolute rate or absolute value that the UE can use to replace the old timing drift rate or a differential (or relative) rate that the UE can use to modify the old timing drift rate. Thus, the techniques described herein include several methods for implementing TA maintenance in NTNs, which can be implemented independently or in any combination to better ensure proper transmission timing and synchronization within the NTN.

[0023] Figure 11 is an exemplary network 100 according to one or more implementations described herein. Exemplary network 100 may include UEs 110-1, 110-2, etc. (collectively, "UE 110" and individually, "UE 110"), a radio access network (RAN) 120, a core network (CN) 130, an application server 140, an external network 150, and satellites 160-1, 160-2, etc. (collectively, "satellite 160" and individually, "satellite 160"). As shown, network 100 may include a non-terrestrial network (NTN) including one or more satellites 160 (e.g., of a global navigation satellite system (GNSS)) in communication with UE 110 and RAN 120.

[0024] The systems and devices of the exemplary network 100 may operate in accordance with one or more communication standards, such as the 2nd Generation (2G), 3rd Generation (3G), 4th Generation (4G) (e.g., Long Term Evolution (LTE)), and / or 5th Generation (5G) (e.g., New Radio (NR)) communication standards of the 3rd Generation Partnership Project (3GPP). Additionally or alternatively, one or more of the systems and devices of the network 100 may operate in accordance with other communication standards and protocols discussed herein, including future versions or generations of 3GPP standards (e.g., 6th Generation (6G) standards, 7th Generation (7G) standards, etc.), Institute of Electrical and Electronics Engineers (IEEE) standards (e.g., Wireless Metropolitan Area Network (WMAN), Worldwide Interoperability for Microwave Access (WiMAX), etc.), and the like.

[0025] As shown, UE 110 may include a smartphone (e.g., a handheld touchscreen mobile computing device that can connect to one or more wireless communication networks). Additionally or alternatively, UE 110 may include other types of mobile or non-mobile computing devices capable of wireless communication, such as a personal data assistant (PDA), a pager, a laptop computer, a desktop computer, a wireless handheld terminal, etc. In some implementations, UE 110 may include an Internet of Things (IoT) device (or IoT UE), which may include a network access layer designed for low-power IoT applications that utilize ephemeral UE connections. Additionally or alternatively, the IoT UE may utilize one or more types of technologies such as machine-to-machine (M2M) communication or machine-type communication (MTC) (e.g., to exchange data with an MTC server or other device via a public land mobile network (PLMN), proximity services (ProSe) or device-to-device (D2D) communication, sensor networks, IoT networks, and more. Depending on the scenario, the M2M or MTC exchange of data may be machine-initiated, and the IoT network may include IoT UEs (which may include uniquely identifiable embedded computing devices within the Internet infrastructure) interconnected via ephemeral connections. In some scenarios, the IoT UE may execute background applications (eg, keep-alive messages, status updates, etc.) to facilitate connectivity to the IoT network.

[0026] UE 110 may communicate and establish a connection (e.g., be communicatively coupled) with RAN 120, which may involve one or more radio channels 114-1 and 114-2, each of which may include a physical communication interface / layer. In some implementations, the UE may be configured with dual connectivity (DC) as a multi-radio access technology (multi-RAT) or multi-radio dual connectivity (MR-DC), where a UE capable of multiple reception and transmission (Rx / Tx) may use resources provided by different network nodes (e.g., 122-1 and 122-2), which may be connected via a non-ideal backhaul (e.g., one network node provides NR access and the other network node provides E-UTRA for LTE or NR access for 5G). In such a scenario, one network node may act as a master node (MN) and the other node may act as a secondary node (SN). The MN and SN may be connected via a network interface, and at least the MN may be connected to CN 130. In addition, at least one of the MN or the SN can operate with shared spectrum channel access, and the functions specified for the UE 110 can be used for an integrated access and backhaul mobile terminal (IAB-MT). Similar to the UE 101, the IAB-MT can access the network using one network node or using two different nodes with an enhanced dual connectivity (EN-DC) architecture, a new radio dual connectivity (NR-DC) architecture, etc.

[0027] As shown, UE 110 may also or alternatively be connected to access point (AP) 116 via interface 118, which may include an air interface that enables UE 110 to communicatively couple with AP 116. AP 116 may include a wireless local area network (WLAN), a WLAN node, a WLAN termination point, etc. Connection 1207 may include a local wireless connection, such as a connection consistent with any IEEE 702.11 protocol, and AP 116 may include a wireless fidelity protocol. Router or other AP. Figure 1 10. Although not explicitly depicted in the figure, AP 116 may be connected to another network (e.g., the Internet) without being connected to RAN 120 or CN 130. In some scenarios, UE 110, RAN 120, and AP 116 may be configured to utilize LTE-WLAN aggregation (LWA) technology or LTE WLAN radio level technology integrated with IPsec tunneling (LWIP). LWA may involve RAN 120 configuring UE 110 in the RRC_CONNECTED state to utilize radio resources of LTE and WLAN. LWIP may involve UE 110 using WLAN radio resources (e.g., connection interface 118) via an IPsec protocol tunnel to authenticate and encrypt packets (e.g., Internet Protocol (IP) packets) transmitted through connection interface 118. IPsec tunneling may include encapsulating the entire original IP packet and adding a new packet header, thereby protecting the original header of the IP packet.

[0028] The RAN 120 can include one or more RAN nodes 122-1 and 122-2 (collectively, RAN nodes 122, and individually, RAN node 122) that enable a connection 114-1 and 114-2 to be established between the UEs 110 and the RAN 120. The RAN nodes 122 can include network access points configured to provide radio baseband functions based on one or more of the communication technologies described herein (e.g., 2G, 3G, 4G, 5G, WiFi, etc.) for use by users and networks. Thus, the RAN nodes can be, for example, E-UTRAN Node Bs (e.g., enhanced Node Bs, eNodeBs, eNBs, 4G base stations, etc.), next generation base stations (e.g., 5G base stations, NR base stations, next generation eNBs (gNBs), etc.). The RAN nodes 122 can include road-side units (RSUs), transmission reception points (TRxPs or TRPs), and one or more other types of ground stations (e.g., ground access points). In some scenarios, the RAN nodes 122 can be dedicated physical devices such as macrocell base stations and / or low power (LP) base stations for providing femtocells, picocells, or other similar small area cells with smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells. As described below, in some implementations, the satellites 160 can operate as base stations (e.g., RAN nodes 122) relative to the UEs 110. Thus, references herein to base stations, RAN nodes 122, etc. can refer to implementations in which the base stations, RAN nodes 122, etc. are ground-based network nodes, and also to implementations in which the base stations, RAN nodes 122, etc. are non-ground-based network nodes (e.g., satellites 160).

[0029] Some or all of the RAN nodes 120 may be implemented as one or more software entities running on a server computer as part of a virtual network, which may be referred to as a centralized RAN (CRAN) and / or a virtual baseband unit pool (vBBUP). In these implementations, the CRAN or vBBUP may implement a RAN functional split, such as a packet data convergence protocol (PDCP) split, where the radio resource control (RRC) and PDCP layers may be operated by the CRAN / vBBUP, and other layer 2 (L2) protocol entities may be operated by individual RAN nodes 122; a medium access control (MAC) / physical (PHY) layer split, where the RRC, PDCP, radio link control (RLC), and MAC layers may be operated by the CRAN / vBBUP, and the PHY layer may be operated by individual RAN nodes 122; or a "lower PHY" split, where the RRC, PDCP, RLC, MAC layer, and upper portions of the PHY layer may be operated by the CRAN / vBBUP, and the lower portions of the PHY layer may be operated by individual RAN nodes 122. The virtualization framework may allow idle processor cores of the RAN node 122 to perform or execute other virtualized applications.

[0030] In some implementations, the individual RAN nodes 122 may represent respective gNB distributed units (DUs) connected to a gNB control unit (CU) via respective F1 interfaces. In such implementations, the gNB-DUs may include one or more remote radio heads or radio frequency (RF) front-end modules (RFEMs), and the gNB-CUs may be operated by a server (not shown) located in the RAN 120 or by a server pool (e.g., a group of servers configured to share resources) in a manner similar to a CRAN / vBBUP. Additionally or alternatively, one or more of the RAN nodes 120 may be next-generation eNBs (i.e., gNBs) that may provide Evolved Universal Terrestrial Radio Access (E-UTRA) user plane and control plane protocol terminations to the UE 110 and may be connected to the 5G core network (5GC) 130 via an NG interface.

[0031] Any of the RAN nodes 122 can serve as an endpoint for the air interface protocol and can be the first point of contact for the UE 110. In some implementations, any of the RAN nodes 122 can perform various logical functions of the RAN 120, including but not limited to functions of a radio network controller (RNC), such as radio bearer management, uplink and downlink dynamic radio resource management, data packet scheduling, and mobility management. The UEs 110 can be configured to communicate with each other or with any of the RAN nodes 122 using orthogonal frequency division multiplexing (OFDM) communication signals over multi-carrier communication channels according to various communication technologies, such as, but not limited to, OFDMA communication technologies (e.g., for downlink communications) or single-carrier frequency division multiple access (SC-FDMA) communication technologies (e.g., for uplink and ProSe or sidelink (SL) communications), although the scope of such implementations may not be limited in this respect. OFDM signals may include multiple orthogonal subcarriers.

[0032] In some implementations, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes 122 to the UE 110, and similar techniques can be used for uplink transmissions. The grid can be a time-frequency grid (e.g., a resource grid or a time-frequency resource grid) that represents the physical resources for the downlink in each time slot. This type of time-frequency plane representation is common for OFDM systems and makes radio resource allocation intuitive. Each column and row of the resource grid corresponds to an OFDM symbol and an OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to a time slot in a radio frame. The smallest time-frequency unit in the resource grid is represented as a resource element. Each resource grid includes resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block can include a set of resource elements (REs); in the frequency domain, this can represent the minimum amount of resources that can currently be allocated. Such resource blocks are used to transmit several different physical downlink channels.

[0033] In addition, the RAN nodes 122 may be configured to wirelessly communicate with the UE 110 and / or each other over a licensed medium (also referred to as a "licensed spectrum" and / or a "licensed band"), an unlicensed shared medium (also referred to as an "unlicensed spectrum" and / or an "unlicensed band"), or a combination thereof. The licensed spectrum may include channels operating in a frequency range of approximately 400 MHz to approximately 3.8 GHz, while the unlicensed spectrum may include a 5 GHz band. The licensed spectrum may correspond to channels or frequency bands that are selected, reserved, regulated, etc. for certain types of wireless activities (e.g., wireless telecommunications network activities), while the unlicensed spectrum may correspond to one or more frequency bands that are not restricted for certain types of wireless activities. Whether a particular frequency band corresponds to a licensed medium or an unlicensed medium may depend on one or more factors, such as frequency allocations determined by a public sector organization (e.g., a government agency, a regulatory agency, etc.) or by a private sector organization involved in developing wireless communication standards and protocols.

[0034] To operate in the unlicensed spectrum, the UE 110 and the RAN node 122 may operate using license-assisted access (LAA), eLAA, and / or feLAA mechanisms. In these implementations, the UE 110 and the RAN node 122 may perform one or more known medium sensing operations or carrier sensing operations to determine whether one or more channels in the unlicensed spectrum are unavailable or otherwise occupied before transmitting in the unlicensed spectrum. The medium / carrier sensing operations may be performed in accordance with a listen-before-talk (LBT) protocol.

[0035] The LAA mechanism can be built on the carrier aggregation (CA) technology of the LTE-Advanced system. In CA, each aggregated carrier is called a component carrier (CC). In some cases, each CC may have a different bandwidth from other CCs. In a time division duplex (TDD) system, the number of CCs and the bandwidth of each CC may be the same for DL ​​and UL. CA also includes individual serving cells to provide each CC. The coverage of the serving cells may be different, for example, because CCs on different frequency bands will experience different path losses. The primary serving cell or PCell can provide a primary component carrier (PCC) for both UL and DL, and can handle radio resource control (RRC) and non-access layer (NAS) related activities. Other serving cells are called SCells, and each SCell can provide a single secondary component carrier (SCC) for both UL and DL. SCCs can be added and removed as needed, and changing the PCC may require UE110 to undergo a handover. In LAA, eLAA, and feLAA, some or all of the SCells may operate in unlicensed spectrum (referred to as "LAA SCells"), and the LAA SCells are assisted by PCells operating in licensed spectrum. When a UE is configured with more than one LAA SCell, the UE may receive UL grants on the configured LAA SCells indicating different PUSCH start positions within the same subframe.

[0036] The PDSCH may carry user data and higher-layer signaling to UE 110. The physical downlink control channel (PDCCH) may carry information regarding, among other things, the transport format and resource allocation associated with the PDSCH channel. The PDCCH may also inform UE 110 of the transport format, resource allocation, and hybrid automatic repeat request (HARQ) information associated with the uplink shared channel. Typically, downlink scheduling (e.g., allocating control and shared channel resource blocks to UE 110-2 within a cell) may be performed on any of RAN nodes 122 based on channel quality information fed back from any of UEs 110. Downlink resource allocation information may be sent on the PDCCH for (e.g., allocated to) each of UEs 110.

[0037] PDCCH uses control channel elements (CCE) to convey control information, where many CCEs (e.g., 6, etc.) can be composed of resource element groups (REGs), where REGs are defined as physical resource blocks (PRBs) in OFDM symbols. Before being mapped to resource elements, PDCCH complex-valued symbols can first be organized into quadruplets, which can then be arranged, for example, using a sub-block interleaver for rate matching. One or more of these CCEs can be used to transmit each PDCCH, where each CCE can correspond to nine sets of four physical resource elements, respectively, called REGs. Four quadrature phase shift keying (QPSK) symbols can be mapped to each REG. Depending on the size of the DCI and the channel conditions, one or more CCEs can be used to transmit the PDCCH. Four or more different PDCCH formats with different numbers of CCEs (e.g., aggregation levels, L=1, 2, 4, 8, or 16) can be defined in LTE.

[0038] Some implementations may use the concept of resource allocation for control channel information, which is an extension of the above concept. For example, some implementations may utilize an extended (E)-PDCCH that uses PDSCH resources for control information transmission. One or more ECCEs may be used to transmit EPDCCH. Similar to the above, each ECCE may correspond to a set of nine four physical resource elements, called EREGs. In some cases, an ECCE may have other numbers of EREGs.

[0039] The RAN nodes 122 can be configured to communicate with one another via an interface 123. In implementations where the system 100 is an LTE system, the interface 123 can be an X2 interface. The X2 interface can be defined between two or more RAN nodes 122 that connect to a Evolved Packet Core (EPC) or CN 130, e.g., two or more eNBs / gNBs, or combinations thereof, and / or between two eNBs connected to the EPC. In some implementations, the X2 interface can include an X2 user plane interface (X2-U) and an X2 control plane interface (X2-C). The X2-U can provide flow control mechanisms for user data packets transferred over the X2 interface, and can be used to communicate information about the delivery of user data between eNBs or gNBs. For example, the X2-U can provide specific sequence number information for user data transferred from a master eNB (MeNB) to a secondary eNB (SeNB); information about PDCP packet data units (PDUs) that are successfully in sequence delivered to the UE 110 for user data from the SeNB; information for PDCP PDUs that are not delivered to the UE 110; information about a current minimum desired buffer size at the SeNB for transmission of user data to the UE; and the like. The X2-C can provide intra-LTE access mobility functions (e.g., including context transfer from source to target eNBs, user plane transport control, and the like), load management functions, and inter-cell interference coordination functions.

[0040] As illustrated, the RAN 120 can be connected (e.g., communicatively coupled) to a CN 130. The CN 130 can comprise a plurality of network elements 132 configured to provide various data and telecommunications services to customers / subscribers (e.g., users of UEs 110) connected to the CN 130 via the RAN 120. In some implementations, the CN 130 can include an Evolved Packet Core (EPC), a 5G CN, and / or one or more additional or alternative types of CNs. The components of the CN 130 can be implemented in one physical node or in separate physical nodes, including components to read and execute instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium). In some implementations, Network Function Virtualization (NFV) can be used to virtualize any or all of the above-described network node roles or functions via executable instructions stored in one or more computer-readable storage mediums (described in further detail below). Logics of the CN 130 can be referred to as network slices, and a logic of a portion of the CN 130 can be referred to as a network sub-slice. Network Function Virtualization (NFV) architectures and infrastructures can be used to virtualize one or more network functions on physical resources comprising a combination of industry-standard server hardware, storage hardware, or switches, instead of dedicated hardware. In other words, NFV systems can be used to execute virtual or reconfigurable implementations of one or more EPC components / functions.

[0041] As shown, CN 130, application server (AS) 140, and external network 150 may be connected to each other via interfaces 134, 136, and 138, which may include IP network interfaces. Application server 140 may include one or more server devices or network elements (e.g., virtual network functions (VNFs) that provide applications that use IP bearer resources through CM 130 (e.g., Universal Mobile Telecommunications System Packet Service (UMTS PS) domain, LTE PS data service, etc.). Application server 140 may also or alternatively be configured to support one or more communication services (e.g., IP voice (VoIP session, push-to-talk (PTT) session, group communication session, social network service, etc.) for UE 110 via CN 130. Similarly, external network 150 may include one or more of various networks, including the Internet, thereby providing network access to various additional services, information, interconnectivity, and other network features to the mobile communication network and UE 110.

[0042] As shown, exemplary network 100 may include an NTN that may include one or more satellites 160-1 and 160-2 (collectively, "satellites 160"). Satellites 160 may communicate with UE 110 via a serving link or wireless interface 162 and / or communicate with RAN 120 via a feeder link or wireless interface 164 (depicted individually as 164-1 and 164). In some implementations, satellites 160 may operate as passive or transparent network relay nodes with respect to communications between UE 110 and a terrestrial network (e.g., RAN 120). In some implementations, satellites 160 may operate as active or regenerative network nodes, such that satellites 160 may operate as base stations to UE 110 (e.g., as gNBs for RAN 120) with respect to communications between UE 110 and RAN 120. In some implementations, the satellites 160 can communicate with each other via a direct wireless interface (e.g., 166) or an indirect wireless interface (e.g., via the RAN 120 using interfaces 164-1 and 164-2). Additionally or alternatively, the satellites 160 can include GEO satellites, LEO satellites, or another type of satellite. The satellites 160 can also or alternatively relate to one or more satellite systems or architectures, such as a Global Navigation Satellite System (GNSS), a Global Positioning System (GPS), a Global Navigation Satellite System (GLONASS), a BeiDou Navigation Satellite System (BDS), etc. In some implementations, the satellites 160 can operate as base stations (e.g., RAN nodes 122) relative to the UE 110. Thus, references herein to base stations, RAN nodes 122, etc. can relate to implementations where the base stations, RAN nodes 122, etc. are terrestrial network nodes, as well as implementations where the base stations, RAN nodes 122, etc. are non-terrestrial network nodes (e.g., satellites 160).

[0043] Figure 2 1 is a diagram of exemplary dynamics associated with timing advance (TA) maintenance in an NTN. As shown, UE 110 may be connected to satellite 160-1, and satellite 160-1 may be connected to RAN 120. UE 110 may be located on an aircraft 210, a high-speed train, or another type of high-speed transportation system.

[0044] Before departure of aircraft 210, UE 110 may be stationary and, therefore, UE 110 may determine a TA value based on a common TA value broadcast to all UEs 160 in the coverage area and / or a TA value received by UE 110 as part of a RACH attach procedure. UE 110 may also receive drift rate information corresponding to changes in propagation delay between UE 110 and satellite 160-1 and / or between RAN node 120 and satellite 160-1 due to the speed at which satellite 160-1 is moving in direction 180. While UE 110 remains stationary in aircraft 210, UE 110 may update UL timing transmissions by determining a new TA value based on the drift rate information, thereby accounting for changes in propagation delay due to changes in the distance between UE 110 and satellite 160-1 and / or between RAN node 120 and satellite 160-1. In some implementations, UE 110 may also or alternatively update the UL timing transmission based on one or more other types of information, such as a newly broadcast common TA, a MAC CE including a TA command from the network, newly received drift rate information, etc.

[0045] At some point, aircraft 210 may begin flying in direction 214, which may be opposite to direction 218 of satellite 160. Consequently, the distance between UE 110 and satellite 160 may increase at a rate based on the combined speed of aircraft 210 and satellite 160. In this scenario, UE 110 may update the timing drift rate used to determine the TA value to accurately represent the speed and trajectory of UE 110 relative to satellite 160-1. In some implementations, UE 110 may update the timing drift rate based on a MAC CE, RRC message, downlink control indicator (DCI), etc. received from the network. UE 110 may update UL timing transmissions by determining a new TA value based on the updated timing drift rate information to better ensure proper synchronization of transmissions within the network.

[0046] Figure 3 FIG. 3 is a flow chart of an exemplary process 300 for TA maintenance in an NTN. The process 300 may be implemented by a UE 110. In some implementations, some or all of the process 300 may be implemented by one or more other systems or devices (including Figure 1 In addition, process 300 may include: Figure 3 One or more fewer, additional, differently ordered, and / or arranged operations than those shown. Figure 3 The exemplary process 300 for TA maintenance that may be performed by UE 110 is discussed in the corresponding description, and thus the scope of the techniques described herein includes processes that may be performed by corresponding base stations (e.g., RAN nodes 112), satellites, and / or reference Figure 1The corresponding processes performed by other network devices described above.

[0047] As shown, process 300 may include receiving a common TA and / or a common timing drift rate from the NTN (block 310). For example, UE 110 may receive a common TA from a satellite 160 connected to a base station (e.g., RAN node 112). The common TA may correspond to the propagation delay between the base station and the satellite 160. In some implementations, the base station may determine the common TA on a per-satellite basis (e.g., by determining an appropriate common TA for each satellite connected to the base station) and may transmit the common TA to the satellite 160. The satellite may broadcast the common TA to UEs 110 within the coverage area of ​​the satellite 160.

[0048] Additionally or alternatively, the base station may determine a common timing drift rate that corresponds to a change in the distance (over time) between the base station and satellite 160. In such implementations, the base station may transmit the common timing drift rate to satellite 160, and satellite 160 may broadcast the common timing drift rate to UE 110, which may be in the same broadcast as the common TA or in a different broadcast. In some implementations, the common timing drift rate may be determined by satellite 160. In some implementations, such as when a satellite is operating regeneratively, the satellite may not broadcast the common TA or the common timing drift rate, or the values ​​of the common TA and the common timing drift rate may be zero (0). In some implementations, the common timing drift rate may vary based on the relative orbital direction and altitude of the corresponding satellites and may be indicated by one or more bit values ​​(e.g., in a RAR, MAC CE, etc.), such as a bit value indicating microseconds per second (y) and / or a scaling factor (S), such that UE 110 may determine the common timing drift rate (x) as: x=y*S.

[0049] Process 300 may also include determining a UE-specific TA (block 320). For example, UE 110 may communicate with satellite 160 to determine the location of UE 110, timestamp information, satellite ephemeris information (e.g., the satellite's position, velocity, orbital trajectory, etc.), etc., and may use this information to determine the UE-specific TA. In some implementations, the UE-specific TA may correspond to a signal propagation delay between UE 110 and satellite 160.

[0050] Process 300 may include determining a TA value based on a common TA, a common timing drift rate, and / or a UE-specific TA (block 330). For example, UE 110 may initially specify a TA value for UL transmissions based on the common TA and the UE-specific TA, and over time, UE 110 may modify the TA value based on the common timing drift rate. Because the common TA may correspond to the propagation delay between the satellite and the base station, the common timing drift rate may correspond to a change in the propagation delay between the satellite 160 and the base station, and the UE-specific TA may account for the change in the propagation delay between the UE 110 and the satellite 160, the resulting TA value may be used by UE 110 to communicate with the base station at an appropriate transmission time. In some implementations, for example, UE 110 may use the TA value to transmit a physical RACH (PRACH) preamble (RACH, Msg1) to the base station to register with the network and establish a connection with the network.

[0051] Process 300 may also include receiving a TA command from the NTN and updating the TA value based on the TA command (block 350). For example, UE 110 may receive a TA command from satellite 160 and update the TA value based on the TA command. In some implementations, the TA command may be received in a RAR message (e.g., Msg2) of a RACH procedure, and UE 110 may modify the old TA for subsequent UL transmissions (e.g., to complete the RACH procedure) based on the TA command. In other scenarios, the TA command may be part of a MAC CE sent to UE 110 after the RACH procedure. For example, the TA command may be received in response to and / or in combination with a specific trigger or event, such as a beam switching event. Thus, the network may be able to enable UE 110 to update the TA value by transmitting a TA command to UE 110 during and / or at some point thereafter during the RACH procedure.

[0052] Although Figure 3Although not shown, UE 110 may also or alternatively receive an updated public TA from the NTN. For example, the base station may determine to broadcast a different public TA to UEs 110 within the coverage area of ​​satellite 160. In some implementations, this may be the result of a change in the distance and / or propagation delay between satellite 160 and the base station. In such implementations, UE 110 may receive the updated public TA and modify the old TA with the new public TA. Similarly, UE 110 may receive an updated public timing drift rate (e.g., via a network broadcast) and determine a TA value for UL transmission based on the updated public timing drift rate. Depending on the implementation, UE 110 may update the TA value using the most recently received public TA, the next public TA to be received, or a combination of the most recently received public TA and the next public TA (e.g., in response to receiving a RAR with TA information, a MAC CE with a TA command, etc.).

[0053] Process 300 may also include obtaining a UE-specific (or dedicated) drift rate and updating the TA value based on the UE-specific timing drift rate (block 360). For example, UE 110 may receive the UE-specific timing drift rate from the base station and / or may update the TA value based on the UE-specific timing drift rate. If / when UE 110 is on an airplane, a high-speed train, and / or otherwise traveling at high speed, the network may determine that the speed and trajectory of UE 110 may adversely affect UL transmissions from UE 110 (e.g., out of synchronization). In such a scenario, the base station may determine the UE-specific timing drift rate of UE 110 (which may include the rate at which the propagation delay between UE 110 and satellite 160 may change) and may communicate the UE-specific timing drift rate to UE 110 (e.g., in a MAC CE, RRC message, DCI, etc.). UE 110 may use the UE-specific timing drift rate to modify the TA value in one or more ways, such as replacing the current timing drift rate, modifying the current timing drift rate, etc. Thus, the techniques described herein can enable TA maintenance to use or account for a timing drift rate specific to UE 110. In some implementations, a common timing drift rate and / or a UE-specific timing drift rate can be used to replace (as an absolute value) or modify (as a relative value) a timing drift rate used for UL transmissions by UE 110. Additionally, the UE-specific timing drift rate can be determined and / or represented as a bit value indicating microseconds per second (y) and / or a scaling factor (S), such that UE 110 can determine the UE-specific timing drift rate (x) as: x=y*S.

[0054] Process 300 may also include receiving a joint TA command and a timing drift rate and updating a TA value based on the joint TA command and the timing drift rate (block 370). For example, UE 110 may receive the joint TA command and the timing drift rate from satellite 160. The joint TA command and the timing drift rate may include a message (e.g., a MAC CE) that includes both the TA command and the timing drift rate. The timing drift rate may include a common timing drift rate, a UE-specific timing drift rate, or a combination thereof. In response, UE 110 may update the TA value using the TA command of the joint message and may apply the timing drift rate of the joint message to the old timing drift rate used by UE 110. Thus, the techniques described herein may enable TA maintenance to include a message from the network that includes different types of information (e.g., a TA command and a timing drift rate) that UE 110 may use to update the TA value.

[0055] Figure 4 4 is a table showing an example of a change in TA value during TA maintenance. As shown, Figure 4 The table may include a horizontal axis 410 representing time, a vertical axis 420 representing TA values, and a line representing changes in TA values ​​with respect to time. In some implementations, example 400 may correspond to a change in TA value for UE 110.

[0056] UE 110 may determine an initial TA value based on a common TA broadcast by the network and / or a UE-specific TA determined by UE 110. UE 110 may also receive a common or cell-specific timing drift rate broadcast by the network and may modify the initial TA value over time by applying the timing drift rate to the initial TA value. The common timing drift rate may be received before, after, or in combination with the initial TA value. As shown, the timing drift rate may be positive, causing the TA value to increase over time (e.g., when the propagation delay between satellite 160 and the base station is increasing). In other implementations, the common timing drift rate may be negative (e.g., when the propagation delay between satellite 160 and the base station is decreasing).

[0057] At some point, UE 110 may receive a TA command from RAN 120. The TA command may be part of a RAR or MAC CE and / or may include a TA command that UE 110 may use to replace or otherwise update a TA value used by UE 110 (e.g., an initial TA value modified by a timing drift rate). As shown, the TA command may include a positive value that may cause the TA value to increase. In some implementations, the TA command may include a negative value that may cause the TA value to decrease (e.g., if the real-time delay (RTD) between the RP and the satellite is greater than the RTD between the RP and the UE and the satellite). Whether the TA command includes a positive or negative value may be indicated in a bit (1 or 0) of a message (e.g., a RAR, MAC CE, etc.) containing the value. As shown, UE 110 may continue to modify the TA value over time based on a timing drift rate (e.g., a cell-specific timing drift rate). The bit indicating a positive or negative RAR message or TA command may be placed immediately before or after the timing advance field (e.g., TA command) of the RAR, MAC CE, etc.

[0058] At some point, UE 110 may receive a new timing drift rate from RAN 120. The new timing drift rate may be part of a MAC CE and / or may include a dedicated or UE-specific timing drift rate and may be a positive or negative rate value. UE 110 may replace or update an old timing drift rate (e.g., a cell-specific timing drift rate) using the new timing drift rate and may apply the updated timing drift rate to the TA value over time. As shown, UE 110 may receive a message (e.g., a MAC CE) from RAN 120 that includes both a TA command, depicted in example 400 as a joint TA command and a UE-specific timing drift rate, and the new timing drift rate. UE 110 may update or replace the old TA value based on the TA command of the joint message.

[0059] As depicted, the TA command may include a negative value, resulting in a decrease in the TA value used for UL transmissions by UE 110. UE 110 may also or alternatively replace or modify the old timing drift rate based on the new timing drift rate value of the joint message, and UE 110 may use the newly updated timing drift rate to modify the TA value over time.

[0060] Figures 5 to 7 is a sequence diagram of an exemplary process 500 for TA maintenance. As shown, the exemplary process 500 may involve UE 110, satellite 160, and base station 122 (also referred to herein as RAN node 122). In some implementations, the exemplary process 500 may include Figures 5 to 7 One or more additional, alternative, fewer or differently arranged operations and / or devices than those shown in FIG. Figures 5 to 7The operations are depicted as being performed by UE 110, satellite 160, or base station 122, but in some implementations, one or more of these operations may be performed by another device or combination of devices of the wireless communication network. For example, in some implementations, one or more of the operations performed by base station 122 may be performed by satellite 160.

[0061] As shown, base station 122 may cause satellite 160 to broadcast a common TA and / or a common timing drift rate to UE 110 within the coverage area of ​​satellite 160 (at 504). In response, UE 110 may obtain the common TA and / or the common timing drift rate and determine an initial TA value based on the common TA and / or the common timing drift rate (at 504). UE 110 may use the TA value to modify the transmission time of a PRACH preamble message sent to base station 122 (at 506), and base station 160 may respond to UE 110 with a RAR message (at 508). As shown, the RAR message may include a TA command. The base station may determine the TA command based on the reception time on the PRACH preamble message (e.g., based on whether the PRACH preamble was received too early or too late).

[0062] UE 110 may utilize the TA command in the RAR to update the old TA value (e.g., for transmitting a PRACH preamble) (at 510). Concurrently, base station 122 may monitor network activity and conditions for a TA update trigger and / or a drift rate trigger (at 512). As described herein, a TA update trigger may include a scenario in which the network determines that a UE 110 in a particular coverage area should adjust UL transmission timing, such as when a satellite previously transmitting to the coverage area moves out of the coverage area and / or a new satellite rotates into the coverage area. Additionally or alternatively, a timing drift trigger may include a scenario in which base station 122 determines that the speed and trajectory of a particular UE 110 (possibly relative to the speed and trajectory of satellite 160) is such that a UE-specific timing drift rate may be required for the UE 112 to remain synchronized with the network.

[0063] Out of Figure 5For purposes of this description, it is assumed that base station 122 does not determine that the TA value or timing drift rate of UE 110 should be modified, so that UE 110 and base station 122 can complete the RACH procedure (at 514). UL transmissions for UE 110 can be transmitted based on the most recent TA value modified by the timing drift rate stored by UE 110. As shown, base station 122 can later detect a TA update trigger (at 516) (e.g., such as a change in satellites 160 with respect to the coverage area of ​​UE 110). Base station 122 can respond by determining a TA command associated with the trigger (at 518) and can transmit the TA command in a MAC CE (at 520). UE 110 can receive the MAC CE and modify the old TA value based on the newly received TA command (at 522). Meanwhile, base station 122 may continue to monitor network activity and conditions for TA update triggers and / or drift rate triggers (at 524), and UE 522 may make UL transmissions to base station 122 using the updated TA value modified over time by the timing drift rate.

[0064] See also Figure 6 , UE 110 may continue to modify the TA value used for UL transmissions based on the timing drift rate stored by UE 110 (at 602). At some point, base station 122 may detect a UE-specific timing drift rate trigger (at 604). For example, UE 110 may be traveling at a high rate of speed on an airplane, on a high-speed train, or otherwise. Base station 122 (and / or satellite 160) may monitor the movement of UE 110 and determine a speed and trajectory based on the movement of UE 110. When the speed and / or trajectory of UE 110 exceeds a specified range or threshold, base station 122 may determine to determine and transmit a UE-specific timing drift rate to UE 110 (at 606). In some implementations, base station 122 and / or satellite 160 may be configured to determine and / or transmit a UE-specific timing drift rate to UE 110 based on one or more other types of criteria or triggers.

[0065] The base station 122 may transmit the UE-specific timing drift rate (at 608) via a MAC CE, which may be the same type or a different type of MAC CE used to transmit the TA command (see, e.g., 522). In some implementations, the base station 122 may transmit the UE-specific timing drift rate in one or more other types of messages, such as in a dedicated RRC message or configuration, DCI, etc. Additionally, the base station 122 may continue to monitor network activity and conditions for TA update triggers and / or drift rate triggers (at 612). In some implementations, the UE-specific timing drift rate may be autonomously implemented by the UE 110 based on ephemeris satellite information, timestamp information, a measured velocity of the UE 110, etc. The UE 110 may modify or update the timing drift rate being applied to the TA value based on the UE-specific timing drift rate (at 614), which may be based on a previously received common (or cell-specific) drift rate (see, e.g., 502). UE 110 may send UL transmissions to base station 122 based on the TA value modified by the newly updated timing drift rate (at 616 and 618), and base station 122 may continue to monitor these transmissions for proper synchronization.

[0066] refer to Figure 7 , UE 110 may continue to modify the TA value for UL transmissions based on the timing drift rate stored by UE 110 (at 702). At some point, base station 122 may detect a trigger, event, condition, etc. associated with sending a joint TA command and timing drift rate to UE 110. In some implementations, this may include a change in the position of satellite 160, a beam switching event, and / or another type of scenario in which the TA value of UE 110 is to be updated to ensure proper transmission timing and synchronization between UE 110, satellite 160, and / or base station 120. The TA command may include a common TA command (e.g., based on a change between base station 120 and satellite 160) and / or a UE-specific TA command (e.g., based on a change between UE 110 and satellite 160).

[0067] In addition, in response to detecting the trigger, the base station 120 may determine appropriate values ​​for the joint TA command and timing drift rate (e.g., based on the detected condition) (at 706), and the base station 120 may transmit the joint TA command and timing drift rate to the UE 110 via a MAC CE (at 708), which may be the same or different from the MAC CE used to transmit the TA command (see, e.g., 522) and / or the UE-specific timing drift rate (see, e.g., 608). In some implementations, the base station 122 may transmit the joint TA command and timing drift rate in one or more other types of signals or messages, such as in a dedicated RRC message or configuration, a downlink control indicator (DCI), etc. In addition, the base station 122 may continue to monitor network activity and conditions for TA update triggers and / or drift rate triggers (at 710). The UE 110 may modify or update the TA value based on the TA command and / or update the current timing drift rate with the newly received drift rate from the base station 122 (at 712). Additionally, UE 110 may send UL transmissions based on the TA value modified over time by the newly updated timing drift rate to base station 122 (at 714 and 716), and base station 122 may continue to monitor the transmissions for proper synchronization.

[0068] Figure 8 8 is a diagram of an example 800 of TA maintenance during beam switching. As shown, example 800 may include UE 110, RAN 120, RAN node (base station) 122, CN 130, satellite 160-1 and satellite 160-2 (collectively referred to as satellite 160). Example 800 also includes the above reference Figure 1 The various interfaces described (e.g., 162, 164, 166, etc.).

[0069] As shown, UE 110 may be connected to RAN 120 via satellite 160-2 and may communicate with satellite 160-2 according to a TA value maintained by UE 110. Examples of UE 110 maintaining a TA value are described throughout the specification. Satellite 160 may move in a direction 810 based on the satellite's orbital trajectory, and UE 110 may move in a direction 820 opposite to direction 810. The movement of UE 110 and / or satellite 160 may prompt a beam switching procedure in the network, whereby UE 110 may remain connected to the network while switching the connection beam from satellite 160-2 to satellite 160-1. The operation of the beam switching procedure may be consistent with the wireless communication standard implemented by the network, such as the 3GPP 5G communication standard. In some implementations, when satellite 160-2 and satellite 160-1 are part of the same cell (e.g., the same logical cell), the beam switching may occur during a serving satellite switch.

[0070] Additionally, because the TA value appropriate for UE 110 to use in communicating with satellite 160-2 may be different from the TA value appropriate for UE 110 to use in communicating with satellite 160-2, the techniques described herein may include processes and procedures whereby the TA value of UE 110 may be maintained and appropriately updated during a beam switching procedure. In some implementations, UE 110 may autonomously update the TA value based on a common TA and / or common timing drift rate associated with satellite 160-1 (e.g., received via a broadcast signal from satellite 160-1). Additionally or alternatively, UE 110 may obtain a UE-specific TA based on, for example, the location of UE 110 and satellite information of satellite 160-1. UE 110 may use the common TA, common timing drift rate, and / or UE-specific TA to determine an appropriate TA value for communicating with satellite 160-1.

[0071] Additionally or alternatively, the network may provide a MAC CE to UE 110 indicating a new TCI state for the UE-specific PDCCH, and the MAC CE may indicate a value for the UE to use in communicating with satellite 160-1. The value may include a TA value (which may replace the old TA value) or a TA difference value that may be used to update the old TA. In some implementations, the network may provide a MAC CE to UE 110 indicating a new TCI state for the UE-specific PDCCH, and the MAC CE may include instructions for UE 110 to determine or update the TA value or communicate with satellite 160-1. In this scenario, UE 110 may respond by determining a TA value based on one or more of the operations described herein (e.g., determining the TA of satellite 160-1 based on one or more of a common TA, a common timing drift rate, an autonomously determined UE-specific timing drift rate, a TA command, a UE-specific timing drift rate from the network, etc.). In some further implementations, the TCI state may be configured or arranged such that the TA value or TA difference used to communicate with satellite 160-1 is included in the TCI state itself. For example, the TCI state for a beam switching procedure may include TCI-State:=sequence{tci-StateId,qcl-Type1,qcl-Type2,TA}. To obtain the TA value, base station 122 may directly signal the TA value described above or signal the ephemeris information of satellite 160-1 so that UE 110 can derive the TA value based on the signaled ephemeris information and the UE's GNSS position information. It is possible to signal both the TA value and the ephemeris information. During a beam switching procedure involving two different satellites, the base station may indicate the bandwidth portion (BWP) used by satellite 160-1 to cover the area of ​​UE 110. The signaling of the BWP may be combined with or separate from the signaling of the TA value.

[0072] As used herein, the term “circuitry” “processing circuitry,” or “logic,” can refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and / or a memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and / or other suitable hardware components that provide the described functionality. In some implementations, circuitry can be implemented in, or functions associated with circuitry can be implemented by, one or more software or firmware modules. In some implementations, circuitry can include logic componentry that can operate at least partially in hardware.

[0073] Figure 9 FIG. 1 is a diagram of an example of components of a device in accordance with one or more implementations described herein. In some implementations, device 900 can include application circuitry 902, baseband circuitry 904, Radio Frequency (RF) circuitry 906, front-end module (FEM) circuitry 908, one or more antennas 910, and power management circuitry (PMC) 912 coupled together at least as shown. The components of device 900 can be included in a UE or a RAN node. In some implementations, device 900 can include less functionality (for example, a RAN node cannot utilize application circuitry 902, but can instead include a processor / controller to process IP data

[0074] Application circuitry 902 can include one or more application processors. For example, application circuitry 902 can include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processors can include general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). Processors can be coupled with or include memory / storage and can be configured to execute instructions stored in the memory / storage to enable various applications or operating systems to run on the device 900. In some implementations, processors of application circuitry 902 can process IP data packets received from an EPC.

[0075] The baseband circuitry 904 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 904 may include one or more baseband processors or control logic components to process baseband signals received from the receive signal path of the RF circuitry 906 and generate baseband signals for the transmit signal path of the RF circuitry 906. The baseband processing circuitry 904 may interact with the application circuitry 902 to generate and process baseband signals and control the operation of the RF circuitry 906. For example, in some implementations, the baseband circuitry 904 may include a third-generation (3G) baseband processor 904A, a fourth-generation (4G) baseband processor 904B, a fifth-generation (5G) baseband processor 904C, or other baseband processors 904D of other existing, developing, or future generations (e.g., second-generation (2G), sixth-generation (6G), etc.). The baseband circuitry 904 (e.g., one or more of the baseband processors 904A-904D) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 906. In other implementations, some or all of the functionality of baseband processors 904A-904D may be included in modules stored in memory 904G and executed via central processing unit (CPU) 904E. Radio control functions may include, but are not limited to, signal modulation / demodulation, encoding / decoding, radio frequency shifting, etc. In some implementations, the modulation / demodulation circuitry of baseband circuitry 904 may include fast Fourier transform (FFT), precoding, or constellation mapping / demapping functionality. In some implementations, the encoding / decoding circuitry of baseband circuitry 904 may include convolution, tail-biting convolution, turbo, Viterbi, or low-density parity check (LDPC) encoder / decoder functionality. The implementation of the modulation / demodulation and encoder / decoder functionality is not limited to these examples and, in other aspects, may include other suitable functionality.

[0076] In some implementations, the baseband circuitry 904 may include one or more audio digital signal processors (DSPs) 904F. The audio DSPs 904F may include components for compression / decompression and echo cancellation, and in other implementations may include other suitable processing elements. In some implementations, the components of the baseband circuitry may be appropriately combined in a single chip, a single chipset, or disposed on the same circuit board. In some implementations, some or all of the components of the baseband circuitry 904 and the application circuitry 902 may be implemented together, such as, for example, on a system on a chip (SOC).

[0077] In some implementations, the baseband circuitry 904 can provide communications compatible with one or more radio technologies. For example, in some implementations, the baseband circuitry 904 can support communications with NG-RAN, Evolved Universal Terrestrial Radio Access Network (EUTRAN), or other wireless metropolitan area networks (WMANs), wireless local area networks (WLANs), wireless personal area networks (WPANs), and the like. Implementations in which the baseband circuitry 904 is configured to support radio communications for more than one wireless protocol can be referred to as multi-mode baseband circuitry.

[0078] The RF circuitry 906 can use modulated electromagnetic radiation to communicate with a wireless network through a non-solid medium. In various implementations, the RF circuitry 906 can include switches, filters, amplifiers, and the like to facilitate communication with the wireless network. The RF circuitry 906 can include a receive signal path that can include circuitry for down-converting RF signals received from the FEM circuitry 908 and providing baseband signals to the baseband circuitry 904. The RF circuitry 906 can also include a transmit signal path that can include circuitry for up-converting baseband signals provided by the baseband circuitry 904 and providing an RF output signal to the FEM circuitry 908 for transmission.

[0079] In some implementations, the receive signal path of RF circuitry 906 may include mixer circuitry 906a, amplifier circuitry 906b, and filter circuitry 906c. In some implementations, the transmit signal path of RF circuitry 906 may include filter circuitry 906c and mixer circuitry 906a. RF circuitry 906 may also include synthesizer circuitry 906d for synthesizing frequencies used by mixer circuitry 906a in the receive and transmit signal paths. In some implementations, mixer circuitry 906a in the receive signal path may be configured to downconvert the RF signal received from FEM circuitry 908 based on the synthesized frequency provided by synthesizer circuitry 906d. Amplifier circuitry 906b may be configured to amplify the downconverted signal, and filter circuitry 906c may be a low-pass filter (LPF) or a band-pass filter (BPF) configured to remove unwanted signals from the downconverted signal to generate an output baseband signal. The output baseband signal may be provided to baseband circuitry 904 for further processing. In some implementations, the output baseband signal can be a zero-frequency baseband signal, but this is not required. In some implementations, the mixer circuit 906a of the receive signal path can include a passive mixer, but the scope of the implementation is not limited in this respect.

[0080] In some implementations, the mixer circuit 906a of the transmit signal path can be configured to upconvert the input baseband signal based on a synthesized frequency provided by the synthesizer circuit 906d to generate an RF output signal for the FEM circuit 908. The baseband signal can be provided by the baseband circuit 904 and can be filtered by the filter circuit 906c.

[0081] In some implementations, the mixer circuit 906a of the receive signal path and the mixer circuit 906a of the transmit signal path may include two or more mixers and may be arranged for quadrature down-conversion and up-conversion, respectively. In some implementations, the mixer circuit 906a of the receive signal path and the mixer circuit 906a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some implementations, the mixer circuit 906a of the receive signal path and the mixer circuit 906a of the transmit signal path may be arranged for direct down-conversion and direct up-conversion, respectively. In some implementations, the mixer circuit 906a of the receive signal path and the mixer circuit 906a of the transmit signal path may be configured for superheterodyne operation.

[0082] In some implementations, the output baseband signal and the input baseband signal can be analog baseband signals, although the scope of the implementation is not limited in this respect. In some alternative implementations, the output baseband signal and the input baseband signal can be digital baseband signals. In these alternative implementations, RF circuitry 906 can include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry, and baseband circuitry 904 can include a digital baseband interface to communicate with RF circuitry 906.

[0083] In some dual-mode implementations, separate radio IC circuitry may be provided to process signals for each spectrum, although the scope of the implementations is not limited in this respect.

[0084] In some implementations, synthesizer circuit 906 d can be a fractional-N synthesizer or a fractional N / N+1 synthesizer, but the scope of the implementation is not limited in this respect, as other types of frequency synthesizers may also be suitable. For example, synthesizer circuit 906 d can be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer including a phase-locked loop with a frequency divider.

[0085] Synthesizer circuit 906d can be configured to synthesize an output frequency based on the frequency input and the divider control input for use by mixer circuit 906a of RF circuit 906. In some implementations, synthesizer circuit 906d can be a fractional-N / N+1 synthesizer.

[0086] In some implementations, the frequency input can be provided by a voltage-controlled oscillator (VCO), although this is not required. The divider control input can be provided by the baseband circuitry 904 or the application processor 902 based on the desired output frequency. In some implementations, the divider control input (e.g., N) can be determined from a lookup table based on the channel indicated by the application processor 902.

[0087] The synthesizer circuit 906d of the RF circuit 906 may include a frequency divider, a delay-locked loop (DLL), a multiplexer, and a phase accumulator. In some implementations, the frequency divider may be a dual-mode divider (DMD), and the phase accumulator may be a digital phase accumulator (DPA). In some implementations, the DMD may be configured to divide the input signal by N or N+1 (e.g., based on a carry-out) to provide a fractional division ratio. In some exemplary implementations, the DLL may include a cascaded, tunable delay element, a phase detector, a charge pump, and a set of D-type flip-flops. In these implementations, the delay elements may be configured to divide the VCO cycle into Nd equal phase groups, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[0088] In some implementations, the synthesizer circuit 906d can be configured to generate a carrier frequency as the output frequency, while in other implementations, the output frequency can be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and can be used with a quadrature generator and divider circuit to generate multiple signals at the carrier frequency with multiple different phases relative to each other. In some implementations, the output frequency can be the LO frequency (fLO). In some implementations, the RF circuit 906 can include an IQ / polarity converter.

[0089] The FEM circuitry 908 may include a receive signal path that may include circuitry configured to operate on RF signals received from one or more antennas 910, amplify the received signals, and provide an amplified version of the received signals to the RF circuitry 906 for further processing. The FEM circuitry 908 may also include a transmit signal path that may include circuitry configured to amplify transmit signals provided by the RF circuitry 906 for transmission via one or more of the one or more antennas 910. In various implementations, amplification by the transmit or receive signal paths may be performed only in the RF circuitry 906, only in the FEM 908, or in both the RF circuitry 906 and the FEM 908.

[0090] In some implementations, the FEM circuitry 908 may include a TX / RX switch to switch between transmit mode operation and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include an LNA to amplify a received RF signal and provide the amplified received RF signal as an output (e.g., to the RF circuitry 906). The transmit signal path of the FEM circuitry 908 may include a power amplifier (PA) to amplify an input RF signal (e.g., provided by the RF circuitry 906) and one or more filters to generate an RF signal for subsequent transmission (e.g., via one or more of the one or more antennas 910).

[0091] In some implementations, the PMC 912 can manage the power provided to the baseband circuitry 904. Specifically, the PMC 912 can control power source selection, voltage scaling, battery charging, or DC-DC conversion. When the device 900 is capable of being powered by a battery, such as when the device is included in a UE, the PMC 912 is typically included. The PMC 912 can improve power conversion efficiency while providing a desired implementation size and heat dissipation characteristics.

[0092] Although Figure 9 The PMC 912 is shown coupled only to the baseband circuitry 904. However, in other implementations, the PMC 912 may additionally or alternatively be coupled to other components (such as, but not limited to, the application circuitry 902, the RF circuitry 906, or the FEM 908) and perform similar power management operations.

[0093] In some implementations, the PMC 912 can control or otherwise be part of various power saving mechanisms of the device 900. For example, if the device 900 is in the RRC_Connected state, in which the device remains connected to the RAN node because it expects to receive traffic soon, then after a period of inactivity, the device can enter a state known as discontinuous reception mode (DRX). During this state, the device 900 can be powered off for short intervals and thereby save power.

[0094] If there is no data traffic activity for an extended period of time, the device 900 may transition to the RRC_Idle state, in which the device is disconnected from the network and does not perform operations such as channel quality feedback, handover, etc. The device 900 enters a very low power state and performs paging, in which the device periodically wakes up again to listen to the network and then powers down again. The device 900 may not receive data in this state; to receive data, the device may transition back to the RRC_Connected state.

[0095] An additional power saving mode can disable the device from using the network for periods exceeding the paging interval (ranging from a few seconds to several hours). During this period, the device is completely unable to connect to the network and can be completely powered down. Any data sent during this period will incur significant latency, assuming that latency is acceptable.

[0096] The processor of the application circuitry 902 and the processor of the baseband circuitry 904 can be used to execute elements of one or more instances of the protocol stack. For example, the processor of the baseband circuitry 904 can be used alone or in combination to perform layer 3, layer 2, or layer 1 functions, while the processor of the application circuitry 904 can utilize data received from these layers (e.g., packet data) and further perform layer 4 functions (e.g., transport communication protocol (TCP) and user datagram protocol (UDP) layers). As mentioned herein, layer 3 may include a radio resource control (RRC) layer, which will be described in further detail below. As mentioned herein, layer 2 may include a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, which will be described in further detail below. As mentioned herein, layer 1 may include a physical (PHY) layer of the UE / RAN node, which will be described in further detail below.

[0097] Figure 10 is a diagram of an exemplary interface of a baseband circuit according to one or more specific implementations described herein. As discussed above, Figure 9 The baseband circuit 904 may include processors 904A-204E and a memory 904G used by the processors. Each of the processors 904A-204E may include a memory interface 1004A-304E, respectively, for sending / receiving data to / from the memory 904G.

[0098] The baseband circuit 904 may also include one or more interfaces to communicatively couple to other circuits / devices, such as a memory interface 1012 (e.g., an interface for sending / receiving data to / from a memory external to the baseband circuit 904), an application circuit interface 1014 (e.g., an interface for sending / receiving data to / from a memory external to the baseband circuit 904), and an application circuit interface 1015 (e.g., an interface for sending / receiving data to / from a memory external to the baseband circuit 904). Figure 9 an interface for sending / receiving data to / from the application circuit 902), an RF circuit interface 1016 (e.g., an interface for sending / receiving data to / from the application circuit 902), Figure 9 an interface for sending / receiving data to / from the RF circuit 906), a wireless hardware connection interface 1018 (e.g., for sending / receiving data to / from a near field communication (NFC) component, Components (e.g. Low power consumption), components and other communication components to send / receive data) and a power management interface 1020 (for example, an interface for sending / receiving power or control signals to / from the PMC 912).

[0099] Examples herein may include subject matter such as a method, components for performing the actions or blocks of the method, and at least one machine-readable medium comprising executable instructions that, when executed by a machine (e.g., a processor with memory, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc.), cause the machine to perform the actions of a method or apparatus or system for concurrent communication using multiple communication technologies according to the described specific implementations and examples.

[0100] In Example 1, a user equipment (UE) device may include: a radio frequency (RF) circuit configured to communicate with a wireless communication network including a non-terrestrial network (NTN) having a satellite; a memory device configured to store instructions; and one or more processors connected to the RF circuit and the memory device and configured to execute the instructions to: determine a timing advance (TA) value for modifying a transmission time of an uplink (UL) signal transmitted to the wireless communication network via the satellite; determine a timing drift rate associated with a change in a signal propagation delay of the UL signal over time; and update the TA value based on the timing drift rate and a measured duration; and cause the RF circuit to transmit the UL signal according to the TA value modified by the timing drift rate and the measured duration.

[0101] In Example 2, the one or more processors are configured to determine the timing drift rate based on a common timing drift rate that is broadcast to UEs in a coverage area associated with the satellite and is associated with a change in signal propagation delay between the satellite and a base station of the wireless communication network. In Example 3, the one or more processors are configured to determine the timing drift rate based on a UE-specific timing drift rate associated with a change in signal propagation delay between the UE and the satellite. In Example 4, the UE-specific timing drift rate is received from the NTN via one of: a radio resource control (RRC) communication; a medium access control (MAC) control element (CE); or a downlink control indicator (DCI).

[0102] In Example 5, the one or more processors are further configured to: update the timing drift rate based on a most recently received timing drift rate from the NTN; and cause the RF circuit to transmit an UL signal based on the updated timing drift rate. In Example 6, the one or more processors are configured to update the timing drift rate based on a most recently received timing drift rate by replacing the timing drift rate with the most recently received timing drift rate. In Example 7, the one or more processors are configured to update the timing drift rate based on a most recently received timing drift rate by combining the timing drift rate with the most recently received timing drift rate. In Example 8, the one or more processors are configured to update the TA value based on timing drift rate information in a medium access control (MAC) control element (CE).

[0103] In Example 9, the one or more processors are configured to update the TA value based on TA information in a medium access control (MAC) control element (CE). In Example 10, the one or more processors are configured to update the TA value based on TA information and timing drift rate information received in a joint TA command and timing drift rate message. In Example 11, the one or more processors are further configured to update the TA value or bandwidth part (BWP) during a beam switching procedure involving an old serving satellite and a new serving satellite.

[0104] In Example 12, the one or more processors are configured to update the TA value based on the common TA by determining an average between the common TA and another common TA previously received from the NTN. In Example 13, the one or more processors are configured to determine the TA value based on: a common TA received from the NTN via broadcast and corresponding to a signal propagation delay between the satellite and the base station; and a UE-specific TA determined by the UE based on a location of the UE and ephemeris information of the satellite.

[0105] In Example 14, a baseband (BB) circuit of a user equipment (UE) device may include one or more processors connected to an RF circuit interface and a memory device and configured to execute instructions to: determine a timing advance (TA) value for modifying a transmission time of an uplink (UL) signal transmitted to the wireless communication network via the satellite; determine a timing drift rate associated with a change in signal propagation delay of the UL signal over time; and update the TA value based on the timing drift rate and a measured duration; and cause the RF circuit to transmit the UL signal according to the TA value modified by the timing drift rate and the measured duration. In Examples 15 to 26, the BB circuit of Example 14 is further modified by applying one or more or any combination of the device features of Examples 2 to 14 as the BB circuit features of Example 27.

[0106] In Example 27, a user equipment (UE) device may include: means for determining a timing advance (TA) value for modifying a transmission time of an uplink (UL) signal transmitted to the wireless communication network via the satellite; means for determining a timing drift rate associated with a change in a signal propagation delay of the UL signal over time; and means for updating the TA value based on the timing drift rate and a measured duration; and means for causing the RF circuit to transmit the UL signal according to the TA value modified by the timing drift rate and the measured duration. In Examples 28 to 39, the UE device of Example 27 is further modified by applying one or more or any combination of the device features of Examples 2 to 14 as the apparatus-plus-function features of Example 27.

[0107] In Example 40, a method performed by a UE may include: determining a timing advance (TA) value for modifying a transmission time of an uplink (UL) signal transmitted to the wireless communication network via the satellite; determining a timing drift rate associated with a change in a signal propagation delay of the UL signal over time; and updating the TA value based on the timing drift rate and a measured duration; and causing the RF circuit to transmit the UL signal according to the TA value modified by the timing drift rate and the measured duration. In Examples 41 to 52, the method of Example 40 is further modified by applying one or more or any combination of the apparatus features of Examples 2 to 14 as method features of Example 40.

[0108] In exemplary claim 53, a computer-readable medium comprising instructions that, when executed by a processor, cause the processor to: determine a timing advance (TA) value for modifying a transmission time of an uplink (UL) signal transmitted via the satellite to the wireless communication network; determine a timing drift rate associated with a change in signal propagation delay of the UL signal over time; and update the TA value based on the timing drift rate and a measured duration; and cause the RF circuit to transmit the UL signal according to the TA value modified by the timing drift rate and the measured duration. In examples 54 to 65, the computer-readable medium of example 53 is further modified by applying one or more or any combination of the apparatus features of examples 2 to 14 as computer-readable medium features of example 53.

[0109] In Example 54, a base station may include: radio frequency (RF) circuitry configured to communicate with a user equipment (UE) device within a coverage area of ​​a satellite of a non-terrestrial network (NTN); a memory device configured to store instructions; and one or more processors connected to the RF circuitry and the memory device and configured to execute the instructions to: receive an uplink (UL) signal originating from a UE of the NTN; determine a timing drift rate for maintaining the TA over time based on movement of the satellite of the NTN; and cause the timing drift rate to be communicated to the UE.

[0110] In Example 55, the processor is further configured to: determine a timing advance (TA) command for modifying a transmission time of an UL signal from the UE based on the UL signal; and cause the TA command to be transmitted to the UE. In Example 56, the UL signal includes a (RACH) preamble, and the TA command is transmitted to the UE via a random access channel (RACH) response (RAR). In Example 57, the TA command is transmitted to the UE via a medium access control (MAC) control element (CE).

[0111] In Example 58 or any of the preceding examples, the processor is further configured to: determine a common TA value corresponding to a signal propagation delay between the satellite and the base station; and cause the common TA value to be broadcast to the UEs within the coverage area of ​​the satellite, so that the UEs adjust the transmission time of UL signals according to the common TA value. In Example 59 or any of the preceding examples, the processor is further configured to: determine a common timing drift rate corresponding to a change in the signal propagation delay between the satellite and the base station of a non-terrestrial network; and cause the common timing drift rate to be broadcast to the UEs within the coverage area of ​​the satellite, so that the UEs adjust the transmission time of UL signals according to the common timing drift rate.

[0112] In Example 60 or any of the preceding examples, the timing drift rate comprises a UE-specific timing drift rate corresponding to a change in signal propagation delay between the UE and the satellite. In Example 61 or any of the preceding examples, the UE-specific timing drift rate is communicated to the UE via one of: a radio resource control (RRC) communication; a medium access control (MAC) control element (CE); or a downlink control indicator (DCI). In Example 62 or any of the preceding examples, the TA command and the UE-specific timing drift rate are communicated to the UE in a single MAC CE.

[0113] In Example 63 or any of the preceding examples, the UE-specific timing drift rate is a relative timing drift rate configured to modify a current timing drift rate used by the UE. In Example 64 or any of the preceding examples, wherein the UE-specific timing drift rate is an absolute timing drift rate configured to replace a current timing drift rate used by the UE. In Example 65 or any of the preceding examples, the base station is a 5thgeneration (5G) base station of a ground network that communicates with UE devices via one or more satellites of the NTN. In Example 66 or any of the preceding examples, the base station is a satellite of the NTN that enables communication between one or more UEs and one or more 5thgeneration (5G) base stations of a ground network.

[0114] In Example 67, a baseband (BB) circuit of a base station can comprise: one or more processors connected to an RF circuit interface and a memory device and configured to execute instructions to: receive an uplink (UL) signal originating from a UE of the NTN; determine a timing drift rate for maintaining the TA over time based on movement of the satellite of the NTN; and cause the timing drift rate to be communicated to the UE. In Examples 68-79, the BB circuit of Example 67 is further modified by applying one or more or any combination of the device features of Examples 55-66 as device features.

[0115] In Example 80, a base station can comprise: means for receiving an uplink (UL) signal originating from a UE of the NTN; means for determining a timing drift rate for maintaining the TA over time based on movement of the satellite of the NTN; and means for causing the timing drift rate to be communicated to the UE. In Examples 81-92, the base station of Example 80 is further modified by applying one or more or any combination of the device features of Examples 55-66 as means plus function features.

[0116] In Example 93, a method performed by a base station or a satellite may include: receiving an uplink (UL) signal from a UE of the NTN; determining a timing drift rate for maintaining the TA over time based on movement of the satellite of the NTN; and causing the timing drift rate to be transmitted to the UE. In Examples 94 to 105, the method of Example 93 is further modified by applying one or more or any combination of the apparatus features of Examples 55 to 66 as method features.

[0117] In exemplary claim 106, a computer-readable medium includes instructions that, when executed by a processor, cause the processor to: receive an uplink (UL) signal from a UE of the NTN; determine a timing drift rate for maintaining the TA over time based on movement of the satellite of the NTN; and cause the timing drift rate to be transmitted to the UE. In examples 107 and 108, the computer-readable medium of example 106 is further modified by applying one or more or any combination of the apparatus features of examples 55 to 66 as computer-readable medium features.

[0118] The above description of illustrative examples, implementations, aspects, etc. of the subject matter of the present disclosure, including what is described in the Abstract, is not intended to be exhaustive or to limit the disclosed aspects to the precise forms disclosed. Although specific examples, implementations, aspects, etc. are described herein for illustrative purposes, various modifications are contemplated within the scope of such examples, implementations, aspects, etc., as those skilled in the relevant art will recognize.

[0119] In this regard, although the subject matter of the present disclosure has been described in conjunction with various examples, implementations, aspects, etc. and corresponding figures, it should be understood that other similar aspects may be used, or modifications and additions may be made to the disclosed subject matter, where applicable, to perform the same, similar, alternative, or alternative functions of the disclosed subject matter without departing from the disclosed subject matter. Accordingly, the disclosed subject matter should not be limited to any single example, implementation, or aspect described herein, but should be construed in accordance with the breadth and scope of the claims appended hereto.

[0120] In particular, with respect to the various functions performed by the aforementioned components or structures (assemblies, devices, circuits, systems, etc.), unless otherwise indicated, the terms used to describe such components (including references to "members") are intended to correspond to any component or structure that performs the specified function of the component (e.g., functionally equivalent), even if not structurally equivalent to the disclosed structures that perform the functions in the exemplary implementations shown herein. In addition, while particular features have been disclosed with respect to only one of a number of implementations, for any given or particular application, such features may be combined with one or more other features of other implementations, as may be desirable and advantageous.

[0121] As used herein, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless specified otherwise or clear from the context, "X employs A or B" is intended to mean any natural inclusive permutation. That is, if X employs A; X employs B; or X employs both A and B, then "X employs A or B" is satisfied in any of the foregoing cases. In addition, the articles "a" and "an" used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from the context to be directed to the singular form. Moreover, to the extent that the terms "including," "comprising," "having," "having," "with," or variations thereof are used in the detailed description and claims, such terms are intended to be inclusive in a manner similar to the term "comprising." Furthermore, where one or more numbered items are discussed (e.g., "a first X," "a second X," etc.), generally, the one or more numbered items can be different or they can be the same, but in some cases, the context may indicate that they are different or that they are the same.

[0122] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly stated to users.

Claims

1. A baseband (BB) circuit of a user equipment (UE), comprising: One or more processors connected to the storage device and configured to execute instructions to: performing beam switching for communication of the UE with a non-terrestrial network (NTN) via switching from an old serving satellite to a new serving satellite; Processing a UE-specific physical downlink control channel (PDCCH) medium access control (MAC) control element (CE) indicating a transmission configuration indicator (TCI) state; and causing the uplink signal to be transmitted to the new serving satellite according to a timing advance (TA) value for modifying a transmission timing of the uplink signal, wherein the TA value is based on a UE-specific TA value included in the TCI state indicated in the MAC CE. 2 . The BB circuit according to claim 1 , wherein the TA value is equal to the UE-specific TA value. The BB circuit according to claim 1 , wherein the TA value replaces an old TA value.

4. The BB circuit of claim 3 , wherein the TA value is further based on: Public TA; and A common timing drift rate received via broadcast and corresponding to a rate of change of the common TA. The BB circuit according to claim 1 , wherein the TA value is a differential TA value for updating an old TA value.

6. The BB circuit of claim 5, wherein the TA value is further based on: Public TA; and A common timing drift rate received via broadcast corresponding to a rate of change of the common TA.

7. The BB circuit of claim 6, wherein the TA value is further based on a UE-specific timing drift rate associated with a change in signal propagation delay.

8. The BB circuit of claim 1, wherein the one or more processors are further configured to connect to a base station via the new serving satellite or the old serving satellite.

9. The BB circuit of claim 1, wherein the new serving satellite and the old serving satellite are part of the same cell before performing the beam switching.

10. A method comprising: performing beam switching for communication of a user equipment (UE) with a non-terrestrial network (NTN) via switching from an old serving satellite to a new serving satellite; receiving a medium access control (MAC) control element (CE) of a UE-specific physical downlink control channel (PDCCH) indicating a transmission configuration indicator (TCI) state; and The uplink signal is transmitted to the new serving satellite according to a timing advance (TA) value for modifying a transmission timing of the uplink signal, wherein the TA value is based on a UE-specific TA value included in the TCI state indicated in the MAC CE. The method according to claim 10 , wherein the TA value is equal to the UE-specific TA value. 12 . The method according to claim 10 , wherein the TA value replaces an old TA value, or the TA value is a differential TA value used to update the old TA value.

13. The method of claim 10, wherein the TA value is further based on: Public TA; and A common timing drift rate received via broadcast and corresponding to a rate of change of the common TA.

14. The method according to claim 10, further comprising: The UE is connected to a base station via the new serving satellite or the old serving satellite.

15. The method of claim 10, wherein the new serving satellite and the old serving satellite are part of the same cell before performing the beam switching.

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