Selectively listen for Tracking Reference Signals (TRS) during Connected Mode Discontinuous Reception (CDRX)

Abstract

Based on whether the device is to switch between repeaters of a base station (e.g., during travel), the device can selectively listen for Tracking Reference Signals (TRS) during Connected Mode Discontinuous Reception (CDRx). The device can determine whether the device is in a High-Speed Train (HST) scenario (e.g., based on the difference between the frequency error generated using Synchronization Signal Blocks (SSB) and the frequency error generated using TRS, based on the trajectory of the frequency error over time or the frequency error difference, based on the instantaneous frequency error, etc.). When the device is in the HST scenario, the device listens for TRS during CDRx, and the device uses the TRS to generate a frequency error. When the device is not in the HST scenario, the device prevents listening for TRS during CDRx (where the SSB received during CDRx is used to generate the frequency error).

Description

[0001] Cross - Reference to Related Applications

[0002] This patent application claims priority to the following applications: U.S. Provisional Patent Application No. 63 / 070,723, filed on August 26, 2020, and titled "SELECTIVE LISTENING FOR A TRACKING REFERENCE SIGNAL DURING CONNECTED MODE DISCONTINUOUS RECEPTION (CDRX)", and U.S. Non - Provisional Application No. 17 / 405,824, filed on August 18, 2021, and titled "SELECTIVE LISTENING FOR A TRACKING REFERENCE SIGNAL (TRS) DURING CONNECTED MODE DISCONTINUOUS RECEPTION (CDRX)", all of which are assigned to the assignee of this application. The disclosures of all prior applications are considered part of this patent application and are incorporated herein by reference. Field of the Invention

[0003] Broadly speaking, the present disclosure relates to wireless communication, and more particularly, to selectively listening for a tracking reference signal (TRS) during connected mode discontinuous reception (CDRx) to track communication frequencies. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcasting, etc. These systems are capable of supporting communication with multiple users by sharing available system resources such as time, frequency, and power. Examples of such multi - access systems include: code - division multiple access (CDMA) systems, time - division multiple access (TDMA) systems, frequency - division multiple access (FDMA) systems, and orthogonal frequency - division multiple access (OFDMA) systems (such as long - term evolution (LTE) systems or fifth - generation (5G) new radio (NR) systems). A wireless multi - access communication system may include multiple base stations or access network nodes, each of which simultaneously supports communication for multiple communication devices (which may alternatively be referred to as user equipment (UE)). Summary of the Invention

[0005] The systems, methods, and devices of the present disclosure each have several innovative aspects, none of which alone is responsible for the desired attributes disclosed herein.

[0006] One innovative aspect of the subject matter described in this disclosure can be implemented in a wireless communication device. An example wireless communication device includes a processing system and an interface. The processing system is configured to: identify whether the wireless communication device is in a High-Speed Train (HST) scenario. The processing system is further configured to: generate a frequency error through one or more Frequency Tracking Loops (FTLs). The interface is configured to: obtain a Tracking Reference Signal (TRS) during Connected Mode Discontinuous Reception (CDRx) when the wireless communication device is in the HST scenario. Generating the frequency error through the one or more FTLs includes: using the TRS when the wireless communication device is in the HST scenario.

[0007] Another innovative aspect of the subject matter described in this disclosure can be implemented in a method of wireless communication. The method can be performed by a wireless communication device. The method can include: identifying whether the wireless communication device is in an HST scenario. The method can further include: receiving a TRS during CDRx when the wireless communication device is in the HST scenario. The method can further include: generating a frequency error using the TRS through one or more FTLs when the wireless communication device is in the HST scenario.

[0008] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following drawings may not be drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic diagram illustrating an example wireless communication system is shown.

[0010] Figure 2A An example of a first 5G NR frame is shown.

[0011] Figure 2B An example of a downlink (DL) channel within a 5G NR time slot is shown.

[0012] Figure 2C An example of a second 5G NR frame is shown.

[0013] Figure 2D An example of an uplink (UL) channel within a 5G NR time slot is shown.

[0014] Figure 3 A schematic diagram illustrating an example base station (BS) and user equipment (UE) is shown.

[0015] Figure 4An example communication system including a BS coupled to multiple repeaters is shown.

[0016] Figure 5 A schematic diagram illustrating an example UE on a high-speed train, which causes a Doppler effect on the wireless communication between the BS and the UE, is shown.

[0017] Figure 6 A flowchart depicting an example operation for generating a frequency error is shown.

[0018] Figure 7 A flowchart depicting another example operation for generating a frequency error is shown.

[0019] Figure 8 A flowchart depicting an example operation for when the wireless communication device is not in a high-speed train (HST) scenario is shown.

[0020] Figure 9 A depiction of an example measurement of a frequency error and an instantaneous frequency error is shown.

[0021] Figure 10 A flowchart depicting an example operation for using the instantaneous frequency error to identify whether the wireless communication device is in an HST scenario is shown.

[0022] Figure 11 A flowchart depicting an example operation for identifying whether the wireless communication device is in an HST scenario based on the number of instantaneous frequency errors is shown.

[0023] Figure 12 A flowchart depicting another example operation for identifying whether the wireless communication device is in an HST scenario based on the number of instantaneous frequency errors is shown.

[0024] Figure 13 A flowchart depicting an example operation for identifying whether the wireless communication device is still in an HST scenario based on the number of instantaneous frequency errors is shown.

[0025] Figure 14 A flowchart depicting another example operation for identifying whether the wireless communication device is still in an HST scenario based on the number of instantaneous frequency errors is shown.

[0026] Figure 15 A depiction of an example frequency error determined using a synchronization signal block and an example frequency error determined using a tracking reference signal from different repeaters is shown.

[0027] Figure 16 A flowchart depicting an example operation for identifying whether the wireless communication device is in an HST scenario based on a frequency error difference is shown. Figure 17A flowchart depicting an example operation for identifying whether a wireless communication device is in an HST scenario based on the number of frequency error differences is shown.

[0028] Figure 18 A flowchart depicting another example operation for identifying whether a wireless communication device is in an HST scenario based on the number of frequency error differences is shown.

[0029] Figure 19 A flowchart depicting an example operation for identifying whether a wireless communication device is still in an HST scenario based on the number of frequency error differences is shown.

[0030] Figure 20 A flowchart depicting another example operation for identifying whether a wireless communication device is still in an HST scenario based on the number of frequency error differences is shown.

[0031] Figure 21 A flowchart depicting an example operation for identifying whether a wireless communication device is in an HST scenario based on the divergence of frequency error over time is shown.

[0032] Figure 22 A flowchart depicting an example operation for determining whether the device is in an HST scenario based on the speed or acceleration of the wireless communication device is shown.

[0033] Figure 23 A flowchart depicting an example operation for determining whether the device is no longer in an HST scenario based on the speed of the wireless communication device is shown.

[0034] Figure 24 A flowchart depicting an example operation for determining whether the device is in an HST scenario based on the location of the wireless communication device is shown.

[0035] Figure 25 A flowchart depicting an example operation for determining whether the device is no longer in an HST scenario based on the location of the wireless communication device is shown.

[0036] Like reference numerals and designations in the various figures indicate like elements. Detailed Description

[0037] For purposes of describing innovative aspects of the present disclosure, the following description is directed to certain embodiments. However, those of ordinary skill in the art will readily recognize that the teachings herein can be applied in many different ways. The described embodiments can be implemented in any device, system, or network capable of transmitting and receiving RF signals according to any of the following IEEE 16.11 standards or any one of the following standards or for communicating within a wireless, cellular, or Internet of Things (IoT) network (such as a system utilizing 3G, 4G, or 5G or further embodiments and technologies thereof), the standards including the IEEE 802.11 standards, (Bluetooth) standards, Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Global System for Mobile Communications (GSM), GSM / General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Terrestrial Trunked Radio (TETRA), Wideband CDMA (W-CDMA), Evolution-Data Optimized (EV-DO), 1xEV-DO, EV-DO Rev A, EV-DO Rev B, High-Speed Packet Access (HSPA), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), Evolved High-Speed Packet Access (HSPA+), Long Term Evolution (LTE), AMPS.

[0038] A base station (BS) can be coupled to one or more repeaters (also referred to as remote radio heads (RRHs)) to extend the coverage area of the BS. Extending the coverage area of the BS can be useful for devices moving through the coverage area (e.g., for devices traveling on a high-speed train (HST)). A BS using one or more repeaters allows a device to remain connected to the BS for a longer period of time (thus reducing the number of handovers between BSs). Additionally, many mobile devices (such as smart phones) support connected-mode discontinuous reception (CDRx, such as defined in Release 8 of the 3rd Generation Partnership Project (3GPP) standard), which allows the mobile device to place one or more radio communication components in a low-power state without losing the connection to the network. During CDRx, the device periodically "wakes up" (moves one or more components out of the low-power state) to listen for information from the BS. One item listened for is the synchronization signal block (SSB), and the received SSB is used to maintain the connection to the network by determining the frequency error in the carrier frequency used by the BS to communicate with the mobile device. When the device is not moving or is moving slowly (and thus, there are few (if any) handovers between repeaters associated with different transmission configuration indicator (TCI) states), the SSB may be sufficient to determine the frequency error in the carrier frequency. However, when the device is moving at a faster speed (which may include an increased number of handovers between repeaters associated with different TCI states), the SSB may not be sufficient to determine the frequency error for the carrier frequency. The device can also listen for the tracking reference signal (TRS) during CDRx, which is used to determine the frequency error in the carrier frequency. The problem with listening for the TRS during CDRx is that more components of the device need to wake up for a longer period of time to listen for the TRS and the SSB (instead of just the SSB), and thus more processing and power resources are required. The ability of the device to selectively determine when to listen for the TRS and when not to listen for the TRS during CDRx is of particular interest.

[0039] A wireless communication device (e.g., a user equipment (UE)) may use implementations of the subject matter described in this disclosure to determine when to listen for a TRS and when not to listen for a TRS during CDRx. In accordance with various aspects of this disclosure, a UE may determine when to listen for a TRS during CDRx based on whether the UE is moving or otherwise in a scenario where it needs to handover between RRHs of a BS. For example, a UE may determine whether the UE is in a high-speed train (HST) scenario (e.g., based on a difference between a frequency error generated using an SSB and a frequency error generated using a TRS, based on a trajectory of the frequency error or the difference in frequency errors over time, based on an instantaneous frequency error caused by a handover between RRHs or other devices associated with different TCI states, or based on other suitable means). When the UE is moving (e.g., the UE is in an HST scenario), the UE listens for and obtains the TRS when the UE is in CDRx. The UE uses the TRS to generate a frequency error via one or more frequency tracking loops (FTLs). The frequency error is used to lock onto a communication frequency used by the UE to receive information (from the BS or a repeater).

[0040] Certain implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages. Selectively determining when to listen for a TRS during CDRx may allow a device to reduce power and processing resource consumption without sacrificing the accuracy of generating a frequency error associated with a wireless communication frequency (which may change due to the Doppler effect). For example, when a device is moving (such as on an HST), the device may listen for and use the TRS to generate a frequency error so that the device can handover between repeaters of a BS (during which generating a frequency error using an SSB may be inaccurate). Otherwise, when the device is not moving (e.g., not on an HST), the device may listen for and use an SSB to generate a frequency error. The device may prevent listening for the TRS during CDRx and allow one or more components to remain in a low-power state for a longer period of time. In this way, listen for and use the TRS when needed to ensure the accuracy of generating a frequency error (and thus allow the device to successfully lock onto a communication frequency), and not listen for and use the TRS when not needed to reduce power and processing resource consumption.

[0041] Figure 1 A schematic diagram of an example wireless communication system 100 is shown. The wireless communication system 100 includes a BS 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The BS 102 may include a macro cell (high-power cellular BS) or a small cell (low-power cellular BS). The macro cell includes the BS. The small cell includes a femto cell, a pico cell, and a micro cell.

[0042] The BS 102 configured for 4G LTE (collectively referred to as the evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 via a backhaul link 132 (e.g., the S1 interface). The BS 102 configured for 5G NR (collectively referred to as the Next Generation RAN (NG-RAN)) can interface with the core network 190 via a backhaul link 184. In addition to other functions, the BS 102 can also perform one or more of the following functions: transmission of user data, encryption and decryption of radio channels, integrity protection, header compression, mobility control functions (such as handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), user and device tracking, radio access network information management (RIM), paging, positioning, and delivery of warning messages. The BS 102 can communicate directly or indirectly with each other (e.g., via the EPC 160 or the core network 190) on a backhaul link 134 (such as the X2 interface). The backhaul link 134 can be wired or wireless.

[0043] BS 102 can communicate wirelessly with UE 104. Each BS 102 in BS 102 can provide communication coverage for a corresponding geographical coverage area 110. There can be overlapping geographical coverage areas 110. For example, the small cell 102' can have a coverage area 110' that overlaps with the coverage area 110 of one or more macro BSs 102. A network including both small cells and macro cells can be referred to as a heterogeneous network. The heterogeneous network can also include a Home evolved Node B (eNB) (HeNB), and the HeNB can provide services to a restricted group called a Closed Subscriber Group (CSG). The communication link 120 between BS 102 and UE 104 can include an uplink (UL) (also referred to as the reverse link) transmission from UE 104 to BS 102 or a downlink (DL) (also referred to as the forward link) transmission from BS 102 to UE 104. The communication link 120 can use multiple-input multiple-output (MIMO) antenna technology, which includes spatial multiplexing, beamforming, or transmit diversity. The communication link can be over one or more carriers. BS 102 / UE 104 can use a spectrum with a bandwidth of up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.) per carrier allocated in carrier aggregation for transmission in each direction, with a total of up to Yx MHz (x component carriers). The carriers can be adjacent to each other or can be non-adjacent to each other. The allocation of carriers can be asymmetric with respect to DL and UL (e.g., more or fewer carriers can be allocated for DL compared to UL). The component carriers can include a primary component carrier and one or more secondary component carriers. The primary component carrier can be referred to as the Primary Cell (PCell), while the secondary component carriers can be referred to as Secondary Cells (SCells).

[0044] Some UEs 104 can communicate with each other using device-to-device (D2D) communication links 158. The D2D communication links 158 can use DL / UL WWAN spectrum. The D2D communication links 158 can use one or more sidelink channels, such as, for example, the Physical Sidelink Broadcast Channel (PSBCH), the Physical Sidelink Discovery Channel (PSDCH), the Physical Sidelink Shared Channel (PSSCH), and the Physical Sidelink Control Channel (PSCCH). D2D communication can be through various wireless D2D communication systems, such as, for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0045] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in the 5 GHz unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a Clear Channel Assessment (CCA) before communication to determine whether the channel is available.

[0046] The small cell 102' may operate in licensed or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed spectrum as used by the Wi-Fi AP 150. The small cell 102' that employs NR in the unlicensed spectrum may enhance the coverage of the access network or increase the capacity of the access network.

[0047] The BS 102 (whether a small cell 102’ or a large cell such as a macro BS) may include an eNB, a gNodeB (gNB), or another type of BS. Some BSs (such as the gNB 180) may operate in the traditional sub 6 GHz spectrum, at millimeter wave (mmW) frequencies, and / or near mmW frequencies to communicate with the UE 104. When the gNB 180 operates at mmW or near mmW frequencies, the gNB 180 may be referred to as a millimeter wave or mmW BS. The Extremely High Frequency (EHF) is a part of the RF in the electromagnetic spectrum. The EHF has a range of 30 GHz to 300 GHz and has a wavelength between 1 millimeter and 10 millimeters. The radio waves in this band may be referred to as millimeter waves. Near mmW may extend down to a frequency of 3 GHz, having a wavelength of 100 millimeters. The Super High Frequency (SHF) band extends between 3 GHz and 30 GHz and is also referred to as centimeter waves. Communication using the mmW / near mmW radio frequency band (e.g., between 3 GHz–300 GHz) has extremely high path loss and short distance. The mmW BS 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short distance.

[0048] BS 180 can send beamforming signals to UE 104 on one or more transmission directions 182’. UE 104 can receive beamforming signals from BS 180 on one or more reception directions 182”. UE 104 can also send beamforming signals to BS 180 on one or more transmission directions. BS 180 can receive beamforming signals from UE 104 on one or more reception directions. BS 180 and UE 104 can perform beam training to determine the optimal reception and transmission directions for each of BS 180 and UE 104. The transmission directions and reception directions for BS 180 can be the same or can be different. The transmission directions and reception directions for UE 104 can be the same or can be different.

[0049] EPC 160 can include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. MME 162 can communicate with a Home Subscriber Server (HSS) 174. MME 162 is a control node that processes the signaling between UE 104 and EPC 160. Generally speaking, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. PDN Gateway 172 provides IP address allocation to the UE and other functions. PDN Gateway 172 and BM-SC 170 are connected to IP services 176. IP services 176 can include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS streaming service, or other IP services. BM-SC 170 can provide functions for MBMS user service provisioning and transmission. BM-SC 170 can serve as an entry point for MBMS transmission for content providers, can be used to authorize and initiate MBMS bearer services within a Public Land Mobile Network (PLMN), and can be used to schedule MBMS transmission. MBMS Gateway 168 can be used to distribute MBMS services to BSs 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area for a particular service being broadcast, and can be responsible for session management (start / stop) and for collecting charging information related to MBMS.

[0050] The core network 190 may include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may communicate with a Unified Data Management unit (UDM) 196. The AMF 192 is a control node that processes signaling between the UE 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS streaming service, or other IP services.

[0051] The BS may also be included or referred to as a gNB, Node B, evolved Node B (eNB), access point, base station transceiver, radio BS, radio transceiver, transceiver function, Basic Service Set (BSS), Extended Service Set (ESS), Transmission and Reception Point (TRP), or some other suitable term. The BS 102 provides an access point to the EPC 160 or the core network 190 for the UE 104. Examples of the UE 104 include cellular phones, smart phones, Session Initiation Protocol (SIP) phones, laptop computers, personal digital assistants (PDAs), satellite radio units, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet computers, smart devices, wearable devices, vehicles, utility meters, gas pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other similar functional devices. Some of the UEs in the UE 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, ovens, vehicles, heart monitors, etc.). The UE 104 may also be referred to as a station, mobile station, user station, mobile unit, user unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile user station, access terminal, mobile terminal, wireless terminal, remote terminal, handheld device, user agent, mobile client, client, or some other suitable term.

[0052] Wireless communication system 100 can utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless system 100 can employ LTE Licensed-Assisted Access (LTE-LAA), LTE Unlicensed (LTE U) radio access technology, or 5G NR technology in an unlicensed radio frequency band such as the 5 GHz Industrial, Scientific, and Medical (ISM) band or the 6 GHz UNII band. When operating in an unlicensed radio frequency band, wireless communication devices such as BS 102 and UE 104 can employ a Listen-Before-Talk (LBT) channel access mechanism to ensure that the channel is idle before transmitting data. In some cases, operation in an unlicensed radio frequency band can be based on a Carrier Aggregation (CA) configuration that combines component carriers (CCs) operating in a licensed band. Operation in an unlicensed radio frequency band can include downlink transmission, uplink transmission, or both. Duplexing in an unlicensed radio frequency band can be based on Frequency Division Duplexing (FDD), Time Division Duplexing (TDD), or a combination of both.

[0053] Wireless communication system 100 can also include or support vehicle-based communication. A vehicle-based communication network can provide always-on telematics where UE 104 (referred to herein as a v-UE) communicates directly with V2N, with pedestrian UEs (V2P), with infrastructure devices (V2I), and with other v-UEs (such as via a network). A vehicle-based communication network can support a safe, always-connected driving experience by providing intelligent connectivity in which traffic signals / timing, real-time traffic and routes, safety alerts for pedestrians / cyclists, collision avoidance information, etc. are exchanged.

[0054] Figure 2A An example of a first time slot 200 within a 5G / NR frame structure is shown. Figure 2B An example of a DL channel 230 within a 5G / NR time slot is shown. Figure 2C An example of a second time slot 250 within a 5G / NR frame structure is shown. Figure 2D An example of a UL channel 280 within a 5G / NR time slot is shown. In some cases, the 5G / NR frame structure can be FDD, where for a particular set of subcarriers (carrier system bandwidth), time slots within the set of subcarriers are dedicated to either DL or UL transmission. In other cases, the 5G / NR frame structure can be TDD, where for a particular set of subcarriers (carrier system bandwidth), time slots within the set of subcarriers are dedicated to both DL and UL transmission. In Figure 2A and Figure 2CIn the example shown, the 5G / NR frame structure is TDD-based, where slot 4 is configured with slot format 28 (with most being DL), where D indicates DL, U indicates UL, and X indicates that the slot is flexible between DL and UL, and where subframe 3 is configured with slot format 34 (with most being UL). Although slots 3 and 4 are shown as having slot formats 34 and 28 respectively, any particular slot can be configured with any of the various available slot formats 0 - 61. Slot formats 0 and 1 are full DL and full UL respectively. The other slot formats 2 - 61 include a mixture of DL, UL, and flexible symbols. A UE can be configured with a slot format by a Slot Format Indicator (SFI) (dynamically configured via Downlink Control Information (DCI) or semi-statically configured via Radio Resource Control (RRC) signaling). The configured slot format can also be applied to the TDD-based 5G / NR frame structure.

[0055] Other wireless communication technologies may have different frame structures or different channels. A frame can be divided into multiple subframes of equal size. For example, a frame with a duration of 10 microseconds (μs) can be divided into 10 subframes of equal size, each subframe having a duration of 1 μs. Each subframe can include one or more slots. A subframe can also include mini-slots, and a mini-slot can include 7, 4, or 2 symbols. Each slot can include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot can include 14 symbols, and for slot configuration 1, each slot can include 7 symbols. The symbols on the DL can be Cyclic Prefix (CP) OFDM (CP-OFDM) symbols. The symbols on the UL can be CP-OFDM symbols (e.g., for high throughput scenarios) or Discrete Fourier Transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also known as Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols) (e.g., for power-constrained scenarios).

[0056] The number of slots within a subframe can be based on the slot configuration and numerology. For slot configuration 0, different numerologies (μ) 0 to 5 allow 1, 2, 4, 8, 16, and 32 slots per subframe respectively. For slot configuration 1, different numerologies 0 to 2 allow 2, 4, and 8 slots per subframe respectively. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols per slot and 2 μ slots per subframe. The subcarrier spacing and symbol length / duration are functions of the numerology. The subcarrier spacing can be equal to 2 μ*15 kHz, where the numeral schemes are 0 to 5. Thus, numeral scheme μ = 0 has a subcarrier spacing of 15 kHz, and numeral scheme μ = 5 has a subcarrier spacing of 480 kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figures 2A - 2D An example of slot configuration 0 (with 14 symbols per slot) and numeral scheme μ = 0 (with 1 slot per subframe) is provided. The subcarrier spacing is 15 kHz, and the symbol duration is approximately 66.7 microseconds (μs).

[0057] A resource grid can be used to represent the frame structure. Each slot includes resource blocks (RBs) (also referred to as physical RBs (PRBs)) that span 12 consecutive subcarriers and extend over multiple symbols. The intersection of subcarriers and spans 14 symbols. The intersection of subcarriers and RBs defines multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0058] As Figure 2A shown, some REs carry reference signals (RSs) for the UE. In some configurations, one or more REs may carry demodulation reference signals (DM-RSs) (designated as Rx for a particular configuration, where 100x is the port number, but other DM-RS configurations are possible). In some configurations, one or more REs may carry channel state information (CSI) reference signals (CSI-RSs) for channel measurements at the UE. REs may also include beam measurement reference signals (BRSs), beam refinement reference signals (BRRs), and phase tracking reference signals (PT-RSs).

[0059] Figure 2BAn example of various DL channels within a subframe of a frame is shown. The Physical Downlink Control Channel (PDCCH) carries DCI within one or more Control Channel Elements (CCEs), where each CCE includes nine Resource Element Groups (REGs), and each REG includes four consecutive resource elements (REs) within one OFDM symbol. The Primary Synchronization Signal (PSS) may be in symbol 2 of a specific subframe of a frame. The PSS is used by UE104 to determine subframe or symbol timing and the physical layer identity. The Secondary Synchronization Signal (SSS) may be in symbol 4 of a specific subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the above-mentioned DM-RS. The Physical Broadcast Channel (PBCH) carrying the Master Information Block (MIB) may be logically grouped with the PSS and SSS to form a Synchronization Signal (SS) / PBCH block (also referred to as a Synchronization Signal Block or SSB). The MIB provides the number of resource blocks (RBs) in the system bandwidth and the System Frame Number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information not sent via the PBCH (such as System Information Blocks (SIBs)), and paging messages.

[0060] As shown in Figure 2C Some of the resource elements (REs) carry DM-RS for channel estimation at the BS (indicated as R for a specific configuration, but other DM-RS configurations are possible). The UE may send DM-RS for the Physical Uplink Control Channel (PUCCH) and DM-RS for the Physical Uplink Shared Channel (PUSCH). The PUSCH DM-RS may be sent in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be sent with different configurations depending on whether a short PUCCH or a long PUCCH is sent and according to the specific PUCCH format used. Although not shown, the UE may send a Sounding Reference Signal (SRS). The SRS may be used by the BS for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0061] Figure 2D An example of various UL channels within a subframe of a frame is shown. The PUCCH may be located at the position indicated in one configuration. The PUCCH carries uplink control information (UCI), such as a scheduling request, a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), a Rank Indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a Buffer Status Report (BSR), a Power Headroom Report (PHR), or UCI.

[0062] Figure 3 A block diagram showing an example BS 310 and UE 350 in an access network is presented. In the DL, IP packets from the EPC 160 can be provided to the controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functions. Layer 3 includes the Radio Resource Control (RRC) layer, and layer 2 includes the Service Data Adaptation Protocol (SDAP) layer, the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Medium Access Control (MAC) layer. The controller / processor 375 provides: RRC layer functions associated with: broadcasting of system information (e.g., MIB and SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-Radio Access Technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with: header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with: transmission of upper layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functions associated with: mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0063] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection for the transmission channel, forward error correction (FEC) encoding / decoding for the transmission channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 processes the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols can then be divided into parallel streams. Each stream can then be mapped to OFDM subcarriers, multiplexed with reference signals (e.g., pilot signals) in the time domain or frequency domain, and then combined together using the inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is space precoded to generate multiple spatial streams. Channel estimates from the channel estimator 374 can be used to determine the encoding and modulation schemes, as well as for spatial processing. The channel estimates can be derived based on reference signals transmitted by the UE 350 or channel status feedback. Each spatial stream can then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX can modulate an RF carrier using the corresponding spatial stream for transmission.

[0064] At the UE 350, each receiver 354RX receives signals via its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then uses the fast Fourier transform (FFT) to convert the OFDM symbol stream from the time domain to the frequency domain. The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation points transmitted by the BS 310. These soft decisions can be based on the channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by the BS 310 on the physical channel. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functions.

[0065] The controller / processor 359 may be associated with a memory 360 that stores program code and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between the transport channel and the logical channel to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using the ACK or NACK protocol to support HARQ operations.

[0066] Similar to the functions described in connection with DL transmission by the BS 310, the controller / processor 359 provides: RRC layer functions associated with: system information (e.g., MIB and SIB) capture, RRC connection, and measurement reporting; PDCP layer functions associated with: header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with: transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and, MAC layer functions associated with: mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0067] Channel estimates derived by the channel estimator 358 based on reference signals or feedback sent by the BS 310 may be used by the TX processor 368 to select an appropriate coding and modulation scheme, and for facilitating spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via a separate transmitter 354TX. Each transmitter 354TX may modulate an RF carrier with the corresponding spatial stream for transmission.

[0068] UL transmission is processed at the BS 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives signals via its corresponding antenna 320. Each receiver 318RX recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0069] The controller / processor 375 may be associated with a memory 376 that stores program code and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing, packet reassembly, decryption, header decompression, control signal processing between the transport channel and the logical channel to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using the ACK or NACK protocol to support HARQ operations. Information to be wirelessly transmitted, such as for LTE or NR-based communications, is encoded at the PHY layer and mapped to one or more radio channels for transmission.

[0070] In Figure 3 the example of, each antenna 352 of the UE 350 is coupled to a corresponding transmitter 354TX. However, in a practical implementation, many UEs have fewer transmitters (or transmit chains) compared to receive (RX) antennas. Although not illustrated for simplicity, each transmitter may be coupled to a corresponding power amplifier (PA) that amplifies the signal to be transmitted. The combination of the transmitter and the PA may be referred to herein as a "transmit chain" or "TX chain". To save cost or die area, the same PA may be reused to transmit signals through multiple RX antennas. In other words, one or more TX chains of the UE may be switchably coupled to multiple RX antenna ports.

[0071] Return reference Figure 1 , one or more of the BSs 102 may be coupled to one or more repeaters to extend the coverage area of the BS. In this way, the UE 104 may remain connected to a single BS 102 for a longer time while moving (without the need to switch to a different UE 104). The BS 102 coupled to one or more repeaters may be located in a position where the UE 104 may travel at high speed or over a long distance. In one example, the BS102 coupled to a repeater to serve the UE 104 may be located along a highway or other road used for cars to travel at high speed. In another example, the BS 102 coupled to a repeater to serve the UE 104 may be located along a train track (e.g., for a high-speed train (HST) that may travel at over 200 kilometers per hour (kph)). Although the examples are described with reference to the devices in the HST scenario, aspects of the present disclosure are applicable to devices that may move at high speed (such as greater than a speed threshold) or may travel through the BS coverage area and switch between repeaters of the BS. As used herein, the HST scenario may involve device movement that causes a switch between repeaters of the BS (such as when traveling on an HST).

[0072] Figure 4 FIG. 400 shows an example communication system 400 that includes a BS 402 coupled to a plurality of repeaters 404-408. The BS 402 and the repeaters 404-408 may be coupled to each other via a backhaul 410. Although shown as a wired backhaul, the backhaul 410 may be any suitable wired or wireless backhaul for communicating between one or more of the repeaters 404-408 and the BS 402. Although three repeaters are shown in this example, any number of repeaters (such as one or more repeaters) may be coupled to the BS.

[0073] Each repeater 404-408 coupled to the BS 402 is associated with a unique TCI state. In this way, each repeater may send a downlink control information (DCI) message (such as via a PDCH (such as a PDCCH or a PDSCH)) indicating the TCI state to one or more UEs within the range of that repeater. For example, a UE 480 on an HST 482 (or other mobile vehicle) may be within the coverage area of repeater 404 and the coverage area of repeater 406, and repeaters 404 and 406 indicate their respective TCI states in the DCI message to the UE 480. Each TCI state indicates one or more quasi co-location (QCL) relationships between the RSs. In some implementations, the TCI state indicates the QCL relationship between the PDCH DM-RS and the TRS. As used herein, the TRS may refer to any suitable reference signal for tracking from the BS or the repeater. For example, the TRS may include a phase tracking reference signal (PTRS) defined in the 3GPP release of the standard for 5G / NR. Although the examples herein may refer to the PTRS as the TRS, any suitable tracking reference signal may be used, and the present disclosure is not limited to the provided examples.

[0074] As used herein, "tracking" may refer to determining a carrier frequency or otherwise locking onto a carrier frequency to communicate with a repeater or a BS. Movement between the UE 480 and the repeater 404 may cause a Doppler effect on the signals transmitted between the UE 480 and the repeater 404. The Doppler effect causes the frequency of the carrier signal being received at the UE 480 to be different from the frequency of the carrier signal being transmitted by the repeater 404. The UE 480 may receive an SSB and a TRS from the repeater 404. The SSB or the TRS may be provided to one or more FTLs of the UE 480 to generate a frequency error associated with the carrier signal. For example, the desired carrier frequency (used by the repeater 404 for transmission) may be known. One or more FTLs may generate a frequency error as an indication of the difference between the frequency of the received carrier signal (with the Doppler effect) and the known frequency of the carrier signal at the time of transmission. The local oscillator of the UE 480 may be adjusted to track the frequency of the received carrier signal based on the frequency error and the known frequency of the carrier signal at the time of transmission so that the UE 480 locks onto the carrier signal. Using one or more FTLs to determine the frequency error and adjust the local oscillator is a recursive process to ensure that the UE 480 remains locked onto the carrier signal to communicate with the repeater 404.

[0075] Figure 5 FIG. 500 is a schematic diagram illustrating an example UE on an HST causing a Doppler effect on wireless communication between a BS and the UE. The description is made with reference to communication with a BS Figure 5 , but Figure 5 is also applicable to communication with a repeater coupled to the BS. Figure 5 FIG. shows a UE 580 on an HST 582 moving towards a BS 584 to cause a Doppler effect on wireless communication between the BS 584 and the UE 580. Figure 5 An example is also shown of a UE 590 on an HST 592 moving away from a BS 594 to cause a Doppler effect on wireless communication between the BS 594 and the UE 590. The UEs 580 and 590 may be Figure 4 examples of the UE 480 in Figure 4An example of BS 402 or one of the repeaters 404 - 408. Referring to the example of HST 582 moving towards BS 584, the carrier signal 586 can be used for wireless communication between the UE 580 (on HST 582) and BS 584. Since HST 582 is moving towards BS 584, the carrier signal received by UE 580 from BS 584 (as shown by signal 588) will be at a higher frequency compared to when the carrier signal 586 is transmitted by BS 584. For example, if the frequency of the carrier signal 586 is 1800 MHz, HST 582 is traveling at 200 kph, and assuming radio waves travel at approximately the speed of light, the observed frequency of signal 588 is approximately 2130 MHz. Compared to the frequency of the carrier signal 586 transmitted at 1800 MHz, the observed frequency of signal 588 is approximately 330 MHz higher.

[0076] Referring to the example of HST 592 moving away from BS 594, the carrier signal 596 can be used for wireless communication between the UE 590 (on HST 592) and BS 594. Since HST 592 is moving away from BS 594, the carrier signal received by UE 580 from BS 594 (as shown by signal 598) will be at a lower frequency compared to when the carrier signal 596 is transmitted by BS 594. For example, if the frequency of the carrier signal 596 is 1800 MHz, HST 592 is traveling at 200 kph, and assuming radio waves travel at approximately the speed of light, the observed frequency of signal 598 is approximately 1520 MHz. Compared to the frequency of the carrier signal 596 transmitted at 1800 MHz, the observed frequency of signal 598 is approximately 280 MHz lower.

[0077] As described above, a device (such as UE 580 or 590) may include one or more frequency tracking loops (FTLs) that are used to generate a frequency offset and thus determine the carrier signal frequency (which may also be referred to as the communication frequency), or otherwise lock the device to the carrier signal frequency in the presence of the Doppler effect. For example, the device receives a periodic signal (which may be any suitable reference signal), and the periodic signal is input into one or more FTLs. One or more FTLs generate a frequency error between the observed carrier signal frequency and the transmitter frequency of the carrier signal (such as generating an indication of the frequency error, such as an indication of 330 MHz greater than the transmitted frequency or 280 MHz less than the transmitted frequency from the above example). As used herein, generating a frequency error refers to generating an indication of the frequency error. As used herein, the communication frequency is a combination of the observed carrier signal frequency and the frequency error. In some implementations, one or more FTLs include one or more phase-locked loops (PLLs) for a local oscillator (LO) to adjust the timing signal frequency of the device to lock to the carrier signal. As used herein, locking to a signal refers to using an underlying oscillator or clock to match the carrier signal frequency to allow continued reception or transmission of information via the carrier signal.

[0078] In one example, UE 580 or 590 periodically obtains an SSB (which includes a PSS and an SSS) from a BS (or a repeater), and the period of the SSB at transmission is known (such as based on the known carrier signal frequency). As described above, one or more FTLs may be used to generate a frequency error (which is based on the Doppler effect) using the obtained SSB and the known period of the SSB. For example, UE 580 or 590 may determine the period of the obtained SSB and compare the measured period with the period defined at transmission (where the frequency error is indicated by the difference between the period defined at transmission and the period measured at reception). Referring to the above example where HST 582 or 592 is moving at 200 kph towards or away from BS 584 or 594 and the SSB is transmitted from BS 584 or 594 to UE 580 or 590 at 1800 MHz, when UE 580 is moving towards BS 584, the frequency error may be 1800 - 2130 MHz = -330 MHz, or when UE 590 is moving away from BS 594, the frequency error may be 1800 MHz - 1520 MHz = 280 MHz. In some implementations, a negative frequency error may indicate that the UE is moving towards the BS, while a positive frequency error may indicate that the UE is moving away from the BS. However, any suitable terms may be used to indicate the frequency error.

[0079] While the generation of frequency error has been described above with reference to periodic SSBs obtained from a BS (or repeater), similar steps may be performed using different reference signals or signal components. For example, multiple instances of PTRS (or other suitable TRS) may be obtained, and one or more FTLs may be used to generate a frequency error based on the obtained PTRS instances. For example, the communication frequency (including the Doppler effect) may be for a PDCH. As described above, the PDCH DM-RS may be quasi-co-located (QCL) with a TRS (such as, a PTRS). For example, these two signals may be transmitted by co-located antennas such that the signals share similar characteristics, including similar Doppler shift and similar Doppler spread. The TCI state associated with the BS (or repeater) indicates the QCL relationship between the PDCH DM-RS and the TRS. Thus, the TRS may be used instead of the DM-RS to generate the frequency error and identify the communication frequency for the PDCH.

[0080] Many device and component manufacturers do not provide the QCL relationship between the SSB and the TRS. For example, due to the proximity of the antennas transmitting the SSB and the TRS, the SSB may be physically co-located with the TRS, but the SSB may be beamformed in a different manner than the TRS. Since the SSB may be beamformed in a different manner than the TRS, the SSB and the TRS may not be QCL. However, if there is no repeater for the BS, and if the SSB and the TRS are transmitted by the same antennas that are co-located with each other at the BS, then the frequency or timing error identified based on the SSB may not differ significantly from the frequency or timing error identified based on the TRS. Thus, one or more FTLs may use the SSB (instead of the TRS) to generate the frequency error and thus use the SSB to determine the communication frequency for the PDCH (or another suitable channel).

[0081] Return reference Figure 4, for a BS 402 coupled to one or more repeaters 404-408, each repeater 404-408 transmits an SSB. Thus, if a device is within range of multiple repeaters, the device may receive multiple instances of the SSB from different repeaters. Multiple instances of the SSB from different repeaters may cause problems in generating the correct frequency error for identifying the communication frequency, because the UE may listen to the SSB from the strongest signal (such as the one with the highest power received at the UE). As the UE moves through the coverage area (and thus switches between repeaters, which may cause problems in tracking), the SSBs from different repeaters at different times may be combined into an SSB from a single repeater. In this way, the device may use the SSB from the first repeater to determine the communication frequency for different repeaters with which the device is communicating. However, the TRS from each repeater is associated with a unique TCI state. If the device is to listen to the TRS, the device is configured to listen to the TRS of a particular repeater based on the TCI state configured for that device. Thus, the wireless communication device is able to correctly generate the frequency error using the TRS when moving (and thus switching) between repeaters of the BS. Therefore, in some cases, the TRS should be used instead of the SSB when generating the frequency error and thus when identifying the communication frequency.

[0082] When the wireless communication device is active (or otherwise not using CDRx), in addition to the SSB, the wireless communication device is also configured to listen to and obtain an instance of the TRS. Thus, the device is able to use the TRS to generate a frequency offset and thus determine the communication frequency. However, many devices support CDRx to save power and processing resources. CDRx allows an idle device to be in a low-power state during a known time when the device does not need to listen to the BS (such as when the BS will not transmit to the device), while maintaining the connection with the BS. The BS uses a discontinuous reception (DRx) cycle (e.g., a short or long DRx cycle, as described in Release 8 of the 3GPP standard) to schedule when to transmit to the UE. During a part of each DRx cycle (when the BS will not transmit to the UE), the UE places itself in a low-power mode, while during the remaining part of each DRx cycle, the UE is awake (and listening for signals from the BS).

[0083] When the UE is in CDRx, the UE obtains the SSB from the BS during the DRx cycle. However, by default, the UE may not obtain an instance of the TRS when in CDRx in order to reduce the amount of time the UE will remain awake during the DRx cycle. If the SSB can be used for tracking (such as when the UE is not moving or otherwise switching between repeaters of the BS), the UE may not need to adjust its operation during CDRx for tracking. However, if an instance of the TRS is to be obtained during CDRx (such as for tracking when the UE is moving between repeaters of the BS), the UE configures itself to remain awake for a longer portion of each DRx cycle and obtains an instance of the TRS.

[0084] Some wireless communication devices are able to recognize the HST flag, which may be set for a network serving a device for a user on the HST (e.g., a UE compliant with the NR HST enhancements defined in Release 16 of the 3GPP standard). When the UE is connected to the BS of a network for the HST (serving a user of the HST system), the UE can obtain the HST flag set to true from the BS. The UE can change its operation based on the obtained HST flag (e.g., obtain an instance of the TRS during CDRx for tracking). However, many devices (e.g., UEs prior to Release 16 of the 3GPP standard) cannot recognize the HST flag. In addition, in some cases, the HST flag set to true may be received when the SSB can still be used for tracking. For example, if a user is waiting on a train platform for an extended amount of time, the user's device does not move significantly (such as to cause a handover between repeaters of the BS), and the SSB received from the BS or a repeater can be used to generate a frequency offset and thus determine the communication frequency. In addition, there may be scenarios outside of HST for when the UE will use the TRS for tracking (to which the NR HST enhancements do not apply). For example, a network serving an automotive highway system may include BSs coupled to repeaters such that a UE moving through the network fast enough (and thus switching between repeaters) will use the TRS instead of the SSB for tracking. Therefore, exclusive use of the HST flag may not be sufficient to determine when to use the TRS for tracking.

[0085] In some implementations, a wireless communication device selectively uses TRS for tracking based on whether the device is in an HST scenario. Identifying whether the device is in an HST scenario can be based on one or more of the following: the frequency error difference between the measurements of the frequency errors of using TRS and SSB, the observation of the instantaneous frequency error caused by the change of the TCI state when switching between repeaters, or the observation of the increase in the frequency error difference. Identifying whether the device is in an HST scenario can also be based on the measurement of the movement of the device using one or more sensors or components (such as motion sensors or accelerometers, global positioning system (GPS) receivers used when tracking the movement of the device, Wi-Fi components for wireless positioning, etc.), or based on the position of the device relative to the known location of the network (such as an HST network) associated with the scenario for which the device is to listen for TRS during CDRx. Various examples of how the device identifies whether it is in an HST scenario are provided below.

[0086] Figure 6 A flowchart depicting an example operation 600 for generating a frequency error (which can be used to determine the communication frequency of a wireless communication device) is shown. In some implementations, the example operation 600 can be performed by means in a wireless communication device. The wireless communication device can be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in, or Figure 5 UE 580 or 590 in Figure 3 In some other implementations, the wireless communication device can be part of a UE for performing wireless communication (such as a modem, a wireless front end including or coupled to one or more antennas, and any other device components for performing the operations described herein). For example, the wireless communication device can include Figure 3 one or more of antenna 352, receiver 354RX, RX processor 356, channel estimator 358, or controller 359 of UE 350 in Figure 6 In some implementations, the wireless communication device can include additional components not shown in

[0087] At 602, the wireless communication device identifies whether the wireless communication device is in an HST scenario. As described above, the wireless communication device being in an HST scenario can refer to the wireless communication device moving to cause a handover between repeaters of a BS (such as for a UE traveling in an HST). For example, the wireless communication device can generate one or more of the following to identify whether the wireless communication device is in an HST scenario (such as further described in detail in the examples below): frequency error, instantaneous frequency error, frequency error difference between the frequency error generated using a TRS and the frequency error generated using an SSB, or the trajectory of the frequency error. In some implementations, the wireless communication device can determine the movement (such as speed or acceleration) of the device or the location of the device (which indicates that future movement is possible), which can be used to identify whether the wireless communication device is in an HST scenario.

[0088] At 604, when the wireless communication device is in an HST scenario, the wireless communication device receives a TRS during CDRx. For example, if the wireless communication device identifies that it is in an HST scenario (such as based on the frequency error difference or frequency error trajectory), the SSB received during CDRx may not be sufficient for one or more FTLs to generate a frequency error and thus identify the communication frequency. In this way, the UE can configure itself to stay awake for a longer amount of time during one or more DRx cycles and listen for the TRS during CDRx (such as when the wireless communication device is idle). In this way, the wireless communication device receives the TRS.

[0089] At 606, when the wireless communication device is in an HST scenario, the wireless communication device uses the TRS to generate a frequency error via one or more FTLs. For example, one or more FTLs can generate a frequency error based on the difference between the received frequency of the TRS and the known frequency of the TRS at the time of transmission. As described above, the wireless communication device can identify the communication frequency based on the frequency error (which may be affected by Doppler shift or spreading). For example, the known transmission frequency of a carrier signal can be added to or subtracted from the frequency error to determine the communication frequency of the carrier signal received by the wireless communication device (which includes the Doppler effect).

[0090] In some implementations, the UE can identify that the UE is not in an HST scenario. As described above, when the UE is not in an HST scenario, the SSB received during CDRx can be sufficient for one or more FTLs to generate a frequency error.

[0091] Figure 7 A flowchart depicting another example operation 700 for generating a frequency error is shown. Operation 700 can be performed by means in a wireless communication device. The wireless communication device can be a UE (such asFigure 1 the UE 104 in Figure 3 the UE 350 in Figure 4 the UE 480 in, or Figure 5 the UE 580 or 590 in), or may be included in the UE. In some implementations, in addition to Figure 6 operation 600 in

[0092] At 702, the wireless communication device receives an SSB during CDRx. For example, whether the wireless communication device is to listen or not listen for a TRS during CDRx, the wireless communication device is scheduled to wake up to receive the SSB sent by the BS or the repeater. At 704, when the wireless communication device is not in the HST scenario, the wireless communication device may use one or more FTLs to generate a frequency error using the SSB. For example, the wireless communication device may identify in step 602 that the wireless communication device is not in the HST scenario (such as described in the example below), which may indicate that generating a frequency error based on the received SSB is sufficient for identifying the communication frequency or otherwise locking onto (such as remaining locked onto) the signal. In response to determining that the wireless communication device is not in the HST scenario, the wireless communication device may use one or more FTLs to determine a frequency error based on the SSB received during CDRx. For example, the FTL may use the frequency of the received SSB or the timing of the received SSB to compare with a known transmission frequency or timing to generate a frequency error. As described above, the known transmission frequency of the carrier signal may be added to or subtracted by the frequency error to determine the communication frequency of the carrier signal received by the wireless communication device. Using the SSB instead of the TRS when generating the frequency error may allow one or more components of the wireless communication device to be in a low-power mode when receiving the TRS, thus saving power and processing resources.

[0093] Figure 8 shows a flowchart depicting an example operation 800 for when the wireless communication device is not in the HST scenario. Operation 800 may be performed by a device in the wireless communication device. The wireless communication device may be a UE (such as Figure 1 the UE 104 in Figure 3 the UE 350 in Figure 4 the UE 480 in, or Figure 5 the UE 580 or 590 in), or may be included in the UE. In some implementations, in addition to Figure 7In addition to operation 700 in , operation 800 may also be performed. At 802, when the wireless communication device is not in the HST scenario, the wireless communication device may prevent listening to the TRS during CDRx. In this way, at least a part of the wireless communication device may be in a low power state for a longer part of each DRx cycle to save power and processing resources.

[0094] There are various implementations for how a wireless communication device may determine whether the wireless communication device is in the HST scenario (and thus whether to listen to the TRS during CDRx). Some example implementations are described below. The implementations described below are examples and do not limit the present disclosure to a particular implementation for how to determine whether a device is in the HST scenario.

[0095] In some implementations, identifying whether a wireless communication device is in the HST scenario may be based on the instantaneous frequency error. As used herein, the instantaneous frequency error may refer to a jump in the frequency error between instances of the frequency error generated by one or more FTLs. For example, a wireless communication device periodically generates a frequency error (e.g., multiple times per second). The instantaneous frequency error at time t1 is based on the frequency error associated with time t1 and one or more frequency errors associated with times other than time t1. In some implementations, the instantaneous frequency error at time t1 may be the difference between the frequency error at time t1 and the frequency error at time t0 prior to t1. In some examples, the frequency error at time t0 and the frequency error at time t1 may be consecutive frequency error measurements made by the wireless communication device. In some other examples, the frequency error at time t0 and the frequency error at time t1 may not be consecutive frequency error measurements (e.g., where one or more frequency error measurements are made between time t0 and time t1). As used herein, a frequency error measurement may refer to the generation of a frequency error by one or more FTLs.

[0096] In some implementations, the instantaneous frequency error at time t1 may be the difference between the frequency error at time t1 and a combination of multiple frequency errors prior to time t1 (such as a simple moving average, an exponential moving average, a simple median, a weighted median, etc.). Although, for clarity in describing aspects of the present disclosure, the following examples describe the instantaneous frequency error as the difference between a second frequency error and a first frequency error, any suitable means for generating the instantaneous frequency error may be used.

[0097] Figure 9Depiction 900 shows an example measurement of frequency error and instantaneous frequency error. The frequency error and the instantaneous frequency error are generated by a wireless communication device such as a UE. Depiction 900 includes graphs 902 - 906. Graph 902 is the reference signal received power (RSRP) of the signals received by the UE from different repeaters over time. The RSRP can be measured in decibels milliwatt (dBm). The increase and decrease of the RSRP over time can indicate that the UE is moving between the coverage areas of different repeaters. For example, when the UE moves towards the first repeater, the RSRP increases. When the UE is closest to the first repeater, the RSRP reaches its peak, and when the UE moves away from the first repeater, the RSRP decreases. At a certain moment near time t1 in graph 702, the UE is also in the coverage area of the second repeater, and the UE can also receive signals from the second repeater. As the UE continues to move away from the first repeater and towards the second repeater, the RSRP of the signal from the first repeater decreases (and the RSRP of the signal from the second repeater increases). Based on the RSRP of the signal from the first repeater decreasing below the RSRP threshold (or the RSRP of the signal from the second repeater increasing above the RSRP of the signal from the first repeater or the RSRP threshold (such as, an absolute RSRP threshold, or a threshold relative to the RSRP of the signal from the first repeater)), the UE switches from using the first repeater to using the second repeater for services with the BS.

[0098] The second repeater is associated with a TCI state different from that of the first repeater, and the UE receives an indication of the new TCI state in the received signal. In response to receiving the indication of the new TCI state, the UE switches the TCI state and switches from listening to the TRS from the first repeater and obtaining an instance of the TRS (based on the previous TCI state) to listening to the TRS from the second repeater and obtaining an instance of the TRS (based on the new TCI state). For depiction 900, for most of the time before time t1, the UE uses the first repeater to communicate with the BS, and for most of the time between time t1 and time t2, the UE uses the second repeater to communicate with the BS (where the switch from the first repeater to the second repeater occurs at a certain time near time t1). As shown, a similar occurrence for the RSRP of the signals from the second repeater and the third repeater can occur at time t2, and the UE can switch from the second repeater to the third repeater.

[0099] Graph 904 is the frequency error generated by one or more FTLs of the UE over time. Each point in Graph 904 represents the frequency error generated by the UE at that time. To generate the frequency error, the UE provides one or more obtained TRS instances to one or more FTLs, and the one or more FTLs can generate the frequency error between the frequency of the signal received by the UE and the frequency of the signal transmitted by the repeater (such as described above). In some implementations, the frequency error can be generated as a voltage level, a current level, a digital value, or any other suitable indication of a frequency shift of the carrier signal. The UE can provide the frequency error (such as current) generated from one or more FTLs to a local oscillator to adjust the signal output by the oscillator to the communication frequency that the UE can receive (or can transmit) to compensate for the frequency error. As shown in Graph 704 for the provided example, as the UE moves through the coverage area of the repeater, the frequency error can oscillate between approximately 13.5 kilohertz (kHz) and 14.2 kHz.

[0100] Comparing Graph 902 and Graph 904, when the UE is moving towards the first repeater (and the RSRP in Graph 902 is increasing), the frequency error is at a higher level (above 14 kHz in Graph 904). After the UE becomes closest to the first repeater and starts moving away from the first repeater (and the RSRP in Graph 902 is decreasing), the frequency error in Graph 904 decreases from above 14 kHz to approximately 13.5 kHz. Graph 904 shows the frequency error determined between 14 kHz and 13.5 kHz during the time when the UE is approaching and passing the first repeater (such that the UE starts moving away from the first repeater rather than towards the first repeater).

[0101] Time t1 indicates the time at which the UE generates a frequency error for a TRS instance received from the second repeater. As described above, the UE switches from obtaining an instance of the TRS from the first repeater to obtaining an instance of the TRS from the second repeater at some time near (or at) time t1. As a result of switching from the first repeater to the second repeater for serving by the BS, the Doppler effect suddenly switches from moving away from the serving repeater (the first repeater before t1) to moving towards the serving repeater (the second repeater after t1). In this way, a jump in the frequency error generated by the UE may occur near the handover. For example, graph 904 shows that the generated frequency error can jump from approximately 13.5 kHz to over 14 kHz (no frequency error is generated between the jumps). The difference in frequency error at different times (such as consecutive frequency errors) can be referred to as the instantaneous frequency error, and the jump in the frequency error can be captured in one of the instantaneous frequency errors. As described above, the instantaneous frequency error can be the difference between two consecutive frequency errors. However, any suitable means for generating the instantaneous frequency error can be performed.

[0102] Graph 906 is the instantaneous frequency error generated for each frequency error in graph 904 in depiction 900. Instantaneous frequency error 908 is the instantaneous frequency error associated with the first frequency error generated after switching repeaters. As shown, the instantaneous frequency error can be greater than 600 Hz, which is the difference between the first frequency error of approximately 14.2 kHz (based on the first TRS instance from the second repeater) and the previous frequency error of approximately 13.5 kHz (based on the previous TRS instance from the first repeater). The instantaneous frequency error after instantaneous frequency error 908 in graph 906 returns to approximately 0 Hz (this is because as the UE is moving towards the second repeater, the subsequent frequency error is generated to be approximately 14.2 kHz). Instantaneous frequency error 910 shows a similar jump in frequency error as a result of the UE switching from the second repeater to the third repeater.

[0103] As shown in graph 906, as the UE reaches its closest repeater and starts moving away from the repeater, the instantaneous frequency error can be different from approximately 0 Hz (such as -200 Hz). However, the magnitude of the instantaneous frequency error based on changing the direction towards or away from the repeater is not as large as the instantaneous frequency difference based on the handover between repeaters. In some implementations, using the instantaneous frequency error to identify whether the UE is in an HST scenario may include: the UE comparing the instantaneous frequency error with a frequency threshold, which can indicate that if the instantaneous frequency error is greater than the frequency threshold, the UE is switching between repeaters.

[0104] Any suitable frequency threshold may be used. For example, the frequency threshold may be 400 Hz, 500 Hz, 600 Hz, or any other suitable number. In another example, the frequency threshold may be static or dynamic. For example, the frequency threshold may be set during device calibration or at the end of device production. In another example, the frequency threshold may be set by software or firmware. In additional examples, the frequency threshold may be set by a user, determined based on a previously generated instantaneous frequency error, adjusted based on previous usage or by the user, or may otherwise be defined or adjusted in any suitable manner to attempt to indicate a handover of the UE between repeaters.

[0105] One or more instantaneous frequency errors greater than the frequency threshold may indicate that the wireless communication device is in an HST scenario (or in other scenarios where the wireless communication device is to listen for TRS instances for tracking during CDRx). When the wireless communication device is in an HST scenario, the wireless communication device may configure itself to receive instances of TRS for tracking during CDRx. If the instantaneous frequency error remains below the frequency threshold, the UE may use the SSB received during CDRx for tracking.

[0106] Figure 10 A flowchart depicting an example operation 1000 for using an instantaneous frequency error to identify whether a wireless communication device is in an HST scenario is shown. Operation 1000 may be performed by apparatus in a wireless communication device. The wireless communication device may be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in Figure 5 UE 580 or 590 in Figure 6 ), or may be included in a UE. In some implementations, operation 1000 may be performed in addition to

[0107] At 1002, the wireless communication device receives a first instance of the TRS. At 1004, the wireless communication device receives a second instance of the TRS. For example, when the wireless communication device is active and listening for the TRS from a repeater, the wireless communication device receives instances of the TRS (which may be one or more frames or sub - frames of a signal). If a handover between repeaters occurs between receiving the first TRS instance and the second TRS instance, the first TRS instance may be from a first repeater prior to the handover, and the second TRS instance may be from a second repeater. If no handover occurs between receiving the TRS instances, the first and second TRS instances are from the same repeater. In some implementations, the TRS may be a PTRS, which indicates the phase of a local oscillator at a transmitter or receiver for locking to a carrier signal. For example, the first TRS instance may indicate a first phase of the local oscillator at a first repeater that transmits the TRS in the first instance, and the second TRS instance may indicate a second phase of the local oscillator at a second repeater (if a handover occurs) or at the first repeater (if no handover occurs) that transmits the TRS in the second instance.

[0108] At 1006, the wireless communication device generates a first frequency error using the first instance via one or more FTLs. At 1008, the wireless communication device generates a second frequency error using the second instance via one or more FTLs. For example, if the TRS is a PTRS and the TRS instance indicates the phase of the local oscillator of a repeater, the obtained phase and the associated phase of the local oscillator at the wireless communication device (such as the phase of the local oscillator when receiving the TRS instance) may be provided to one or more FTLs. One or more FTLs may generate an associated frequency error based on the difference between the phases.

[0109] At 1010, the wireless communication device uses the first frequency error and the second frequency error to generate an instantaneous frequency error. In some implementations, the instantaneous frequency error is the difference between the first frequency error and the second frequency error (1012). However, the instantaneous frequency error may be generated in any suitable manner. At 812, the UE determines whether the instantaneous frequency error is greater than a frequency threshold (such as the one described above). If operation 1000 is performed in conjunction with operation 600, then identifying whether the wireless communication device is in an HST scenario (602) includes: identifying whether the instantaneous frequency error is greater than the frequency threshold. As described above, the frequency threshold may be defined to distinguish between when the wireless communication device is handover between repeaters and when it is not.

[0110] If the wireless communication device determines that the instantaneous frequency error is greater than the frequency threshold, the wireless communication device can identify that the wireless communication device is in an HST scenario. In some implementations, identifying whether the wireless communication device is in an HST scenario is based on whether multiple instantaneous frequency errors are greater than the frequency threshold. For example, whether a UE is to listen for a TRS during CDRx can be based on the number of instantaneous frequency errors greater than the frequency threshold being greater than a threshold number. In this way, if the number of handovers between repeaters by the wireless communication device during a period of time is greater than the threshold number, the number of instantaneous frequency errors generated during that time period is greater than that threshold number, indicating that the UE is in an HST scenario (and thus listens for a TRS during CDRx). For example, if the time period is 10 seconds and the threshold number is zero, a single repeater handover during the 10 - second period can indicate that the UE is to listen for a TRS during CDRx (where the number of instantaneous frequency errors greater than the threshold during the 10 - second period is at least one).

[0111] Any suitable threshold number can be used. For example, a threshold number greater than zero can be used to accommodate any interference that may cause one or several instantaneous frequency errors to incorrectly be greater than the frequency threshold. In another example, any suitable time period can be used (such as to balance the latency that can be associated with an increasing time period with the loss of accuracy that can be associated with a decreasing time period). The threshold number and the time period can be static or dynamic. For example, the threshold number or the time period can be set during device calibration or at the end of device production, can be set by software or firmware, can be set by the user, can be determined based on previous measurements, can be adjusted based on previous device usage or by the user, or can be defined or adjusted in any suitable way in other respects.

[0112] Figure 11 A flowchart showing an example operation 1100 for identifying whether a wireless communication device is in an HST scenario based on the number of instantaneous frequency errors is shown. Operation 1100 can be performed by means in the wireless communication device. The wireless communication device can be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in, or Figure 5 UE 580 or 590 in Figure 10 ), or can be included in a UE. In some implementations, operation 1100 can be performed in addition to

[0113] At 1102, a wireless communication device receives multiple TRS instances during a first time period. In some implementations, the multiple TRS instances include a first TRS instance and a second TRS instance from operation 1000. At 1104, the wireless communication device uses the multiple TRS instances to generate multiple instantaneous frequency errors, wherein identifying whether the wireless communication device is in an HST scenario includes: identifying whether the number of instantaneous frequency errors greater than a frequency threshold among the multiple instantaneous frequency errors is greater than a threshold number defined for the HST scenario.

[0114] Figure 12 A flowchart illustrating an example operation 1200 for identifying whether a wireless communication device is in an HST scenario based on the number of instantaneous frequency errors is shown. Operation 1200 can be performed by means in the wireless communication device. The wireless communication device can be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in, or Figure 5 UE 580 or 590 in Figure 11 ), or can be included in a UE. In some implementations, operation 1200 can be an example implementation of operation 1100 in

[0115] At 1202, the wireless communication device obtains multiple TRS instances during a first time period. In some implementations, and in connection with Figure 10 operation 1000 in Figure 9 , the multiple TRS instances can include a first instance and a second instance of the TRS. At 1204, the wireless communication device determines multiple instantaneous frequency errors based on the multiple TRS instances. For example, referring back to Figure 12 , the wireless communication device can determine the frequency error sequence during the time period shown in graph 904. Referring back to Figure 9 , at 904, the wireless communication device can determine multiple instantaneous frequency errors based on the multiple TRS instances. For example, referring back to

[0116] Referring back to Figure 12, at 1206, the wireless communication device determines for each instantaneous frequency error whether the instantaneous frequency error is greater than a frequency threshold. For example, each time the instantaneous frequency error is determined over time, the instantaneous frequency error is compared with the frequency threshold. At decision block 1208, the wireless communication device may determine whether the number of instantaneous frequency errors determined to be greater than the frequency threshold is greater than a threshold number (such as described above). If the number is not greater than the threshold number, the wireless communication device may determine that the wireless communication device is not in an HST scenario (1210), which may indicate that the wireless communication device is not in a scenario in which the wireless communication device is to listen for TRS during CDRx. In some implementations, if the number is not greater than the threshold number, the wireless communication device is configured to use the SSB obtained during CDRx to generate a frequency error (instead of using the TRS). In this way, the UE can prevent listening for the TRS during CDRx (such as allowing the UE to remain in a low power state for a longer period during a DRx cycle).

[0117] Returning to reference decision block 1208, if the number is greater than the threshold number, the wireless communication device may determine that the wireless communication device is in an HST scenario (1212), which may indicate that the wireless communication device is in a scenario in which the wireless communication device is to listen for TRS during CDRx. In some implementations, if the number is greater than the threshold number, the wireless communication device is configured to listen for the TRS during CDRx and obtain an instance of the TRS to generate a frequency error (instead of using the SSB).

[0118] In a specific example of operation 1200, the frequency threshold may be 600 Hz, the threshold number may be 1, and the time period may be 15 seconds (where graphs 902 - 906 span 15 seconds). Graph 904 shows a plurality of frequency errors determined during the time period, and graph 906 shows a plurality of instantaneous frequency errors determined for the plurality of frequency errors. Instantaneous frequency errors 908 and 910 are greater than the frequency threshold of 600 Hz, and the wireless communication device determines the number of instantaneous frequency errors greater than the frequency threshold to be 2. 2 is greater than the threshold number 1. As a result, the wireless communication device may be configured to listen for the TRS during CDRx (since the wireless communication device is in an HST scenario). In another specific example, the parameters are configured such that the wireless communication device determines that the frequency error jumps two or more times during a 5 - second time period (such as the instantaneous frequency error being greater than the frequency threshold of 400 Hz or 600 Hz) to determine that the wireless communication device is in an HST scenario. However, as mentioned herein, any suitable parameters may be used to identify whether the wireless communication device is in an HST scenario.

[0119] If it is determined that the wireless communication device is in an HST scenario, the wireless communication device is configured to obtain a TRS instance whether the wireless communication device is in an active state or the wireless communication device is in an idle state (during CDRx). In this way, the wireless communication device can continue to generate an instantaneous frequency error and determine whether each instantaneous frequency error is greater than a threshold. When the wireless communication device is in an HST scenario, the comparison of the instantaneous frequency error with the threshold can be used to determine whether the wireless communication device remains in the HST scenario over time.

[0120] In some implementations, when the wireless communication device remains in an HST scenario, the wireless communication device remains configured to listen for TRS during CDRx. As long as one or more instantaneous frequency errors remain above a frequency threshold over time, the wireless communication device can remain in the HST scenario. For example, once as a result of the wireless communication device being in an HST scenario, the wireless communication device is configured to listen for TRS during CDRx, the wireless communication device can determine whether the number of instantaneous frequency errors greater than a second frequency threshold within a second time period is greater than a second threshold number.

[0121] For a specific example, refer to Figure 9 , if the wireless communication device has been determined to be in an HST scenario before the time associated with FIGS. 902 - 906, it can be determined whether the wireless communication device remains in the HST scenario based on determining that the number of instantaneous frequency errors greater than the second frequency threshold is higher than the second threshold number.

[0122] The second frequency threshold used to determine whether a wireless communication device is still in the HST scenario can be the same as or different from the above-mentioned frequency threshold used to determine whether the wireless communication device is in the HST scenario (such as for operations 1100 and 1200). The number of second thresholds used to determine whether a wireless communication device is still in the HST scenario can be the same as or different from the number of the above-mentioned thresholds used to determine whether the wireless communication device is in the HST scenario (such as for operations 1100 and 1200). The second time period used to determine whether a wireless communication device is still in the HST scenario can be the same as or different from the above-mentioned time period used to determine whether the wireless communication device is in the HST scenario (such as for operations 1100 and 1200). For example, the number of second thresholds (used to determine whether a wireless communication device is still in the HST scenario) can be less than the number of thresholds previously used to determine that a wireless communication device is in the HST scenario. In this way, remaining in the HST scenario (and thus being configured to listen for TRS during CDRx) can be easier than initially determining that a wireless communication device is in the HST scenario. In another example, the number of second thresholds can be the same as the number of thresholds previously used. In another example, the second time period used to determine whether a wireless communication device is still in the HST scenario can be longer than the time period initially used to determine whether a wireless communication device is in the HST scenario. In this way, the second time period can be of sufficient length to compensate for possible stops and pauses in the movement of the wireless communication device. For example, the second time period can have sufficient length to accommodate the HST stopping at a platform or briefly decelerating (such as for construction, emergencies, for passengers to board and alight, etc.). However, if all the parameters when determining whether a wireless communication device is still in the HST scenario are the same as the parameters when initially determining that the wireless communication device is in the HST scenario, the operation for determining whether the wireless communication device is still in the HST scenario can be the same as Figure 11 the example operation 1100 in Figure 12 or the operation 1200 in

[0123] Figure 13 FIG. shows a flowchart depicting an example operation 1300 for identifying whether a wireless communication device is still in the HST scenario based on the number of instantaneous frequency errors. Operation 1300 can be performed by means in the wireless communication device. The wireless communication device can be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in Figure 5 or UE580 or 590 in Figure 11 ), or can be included in a UE. In some implementations, operation 1300 can be performed in addition to the operation 1100 in

[0124] At 1302, when the wireless communication device is in an HST scenario, the wireless communication device receives a second plurality of TRS instances during a second time period. At 1304, the wireless communication device uses the second plurality of TRS instances to generate a second plurality of instantaneous frequency errors. In some implementations, the second time period may include an amount of time prior to the current time. In this way, the second time period may be a moving window. In some implementations, the second time period may include a defined number of previously generated instantaneous frequency errors. In this way, the second time period may include a rolling number of the last generated instantaneous frequency errors.

[0125] At 1306, the wireless communication device identifies whether the wireless communication device is no longer in an HST scenario. In some implementations of identifying whether the wireless communication device is no longer in an HST scenario, the wireless communication device identifies whether the number of the second plurality of instantaneous frequency errors that is greater than a second frequency threshold is less than a second threshold number defined for the HST scenario (1308). As described above, whether the wireless communication device remains in an HST scenario may be based on whether the instantaneous frequency errors generated during the second time period are higher than the second frequency threshold. In this way, if starting from one or more previous instantaneous frequency errors being greater than the second frequency threshold, as time passes, the instantaneous frequency errors remain below the second frequency threshold, then the wireless communication device identifies that the wireless communication device is no longer in an HST scenario. The second frequency threshold may be associated with whether the wireless communication device is still switching between repeaters of the BS to cause a jump in the instantaneous frequency error (such as depicted in Figure 9 )

[0126] Figure 14 A flowchart illustrating another example operation 1400 for identifying whether a wireless communication device is still in an HST scenario based on the number of instantaneous frequency errors is shown. Operation 1400 may be performed by means in the wireless communication device. The wireless communication device may be a UE (such as UE 104 in Figure 1 , UE 350 in Figure 3 , UE 480 in Figure 4 , or UE 580 or 590 in Figure 5 ), or may be included in a UE. In some implementations, operation 1400 may be an example implementation of operation 1300 in Figure 13 . Note that example operation 1400 may be similar to example operation 1200 in Figure 12 .

[0127] At 1402, after determining that the wireless communication device is in an HST scenario and during a second time period, the wireless communication device obtains a second plurality of TRS instances. At 1404, the wireless communication device determines a second plurality of instantaneous frequency errors based on the second plurality of TRS instances. At 1406, for each of the second plurality of instantaneous frequency errors, the wireless communication device determines whether the instantaneous frequency error is greater than a second frequency threshold. At decision block 1408, the wireless communication device determines whether the number of instantaneous frequency errors determined to be greater than the second frequency threshold is greater than a second threshold number. If the number is not greater than the second threshold number, the wireless communication device identifies that the wireless communication device is no longer in an HST scenario (1410). In this way, the wireless communication device can be configured to use the SSB obtained during CDRx for tracking. In some implementations, the wireless communication device can prevent listening for TRS during CDRx. If the number is greater than the second threshold number, the wireless communication device identifies that the wireless communication device is still in an HST scenario (1412). In this way, the wireless communication device is still configured to listen for TRS during CDRx (and thus obtain TRS instances).

[0128] One or more of the second time period, the second frequency threshold, or the second threshold number for example operation 1400 may be the same as (or different from) the time period, frequency threshold, or threshold number used in example operation 1200 in Figure 12 In this way, identifying when entering an HST scenario may have the same or different constraints as identifying when exiting an HST scenario. As used herein, "time period" may refer to a moving time window, overlapping or non-overlapping time blocks, or any other suitable time measurement. In this way, determining whether the wireless communication device is in an HST scenario or determining whether the wireless communication device is still in an HST scenario may be based on the frequency error determined during a moving time window, during a fixed time block, or during any other suitable measurement of the time period. As described above, the parameter may be any suitable parameter, and the present disclosure is not limited to a specific time period length, a specific frequency threshold, or a specific threshold number.

[0129] As mentioned in the above example implementation, identifying whether a wireless communication device is in an HST scenario can be based on one or more instantaneous frequency errors generated by the wireless communication device. In some implementations that are alternatives or supplements to the above example implementation, identifying whether a wireless communication device is in an HST scenario can be based on a comparison of a frequency error generated using the received SSB and a frequency error generated using the received TRS instance. For example, a wireless communication device can receive SSBs over time and receive instances of TRSs over time. The wireless communication device can use the SSBs to generate a first frequency error sequence and use the TRS instances to generate a second frequency error sequence, and the UE can compare the first frequency error sequence with the second frequency error sequence. Divergence between the first sequence and the second sequence (such as an increasing difference between a frequency error generated based on an SSB and a frequency error generated based on a TRS instance corresponding to the SSB) can indicate that the UE is in an HST scenario.

[0130] Figure 15 Depiction 1500 shows an illustration of example frequency errors determined using an SSB and example frequency errors generated using TRSs from different repeaters. In this example, the SSB and TRS instances are shown as being obtained at different UE positions measured as the UE moves from left to right in the depiction. For example, the UE starts at a position indicated by 0 meters along the horizontal axis and moves 450 meters. In this example, the UE is moving at a high speed (such as greater than 200 kilometers per hour (kph)).

[0131] This depiction 1500 includes three sets of frequency errors 1502 - 1506. Each set of frequency errors includes frequency errors generated periodically during UE movement (such as every 50 meters or 25 meters of UE movement or at defined time intervals). Group 1502 includes frequency errors determined using SSBs obtained from a first repeater or a second repeater (where the UE switches from the first repeater to the second repeater at 350 meters to obtain an SSB). Groups 1504 and 1506 include frequency errors generated using TRS instances obtained from the first repeater or the second repeater. The adjacent frequency errors of each group 1502 - 1506 in the depiction 1500 are connected via lines to illustrate the next frequency error generated for each group. In this way, group 1502 is shown as a first curve, group 1504 is shown as a second curve, and group 1506 is shown as a third curve.

[0132] The position of the second repeater for group 1504 can be different from the position of the second repeater for group 1506. As a result, the UE switches from the first repeater to the second repeater to listen for the TRS at different positions for group 1504 and for group 1506. In this example, for group 1504, the UE switches repeaters at 250 meters to listen for the TRS, or for group 1506, the UE switches repeaters at 450 meters to listen for the TRS. As a result, the second curve and the third curve are similar (with the frequency error for groups 1504 and 1506) until the UE is 250 meters from the starting point in plot 1500. In some other implementations, the difference in the handover points can be based on different delays in the handover (such as the delay based on the configured TCI state, fading, etc.).

[0133] The UE listens to (i) the SSB and (ii) the TRS. In this way, the UE obtains the SSB for group 1502 and also obtains a TRS instance for group 1504 or a TRS example for group 1506. As described above, compared to switching between repeaters for listening to the TRS, the UE can switch between repeaters for listening to the SSB at different points (e.g., in plot 1500, at 350 meters for the SSB, compared to 250 meters or 450 meters for the TRS).

[0134] For example, the position of the UE can be between the first repeater and the second repeater, and the UE can be in the two coverage areas for the first repeater and the second repeater. When the UE is in the two coverage areas, the UE can obtain signals (including the SSB) from both repeaters. When listening to the SSB, the UE can be configured to listen to the SSB of the signal with the highest RSRP from the repeaters (which can be assumed to indicate the nearest repeater). In this way, the UE uses one or more SSBs from the strongest signal at this moment to generate the frequency error.

[0135] When listening to the TRS, the UE switches repeaters for listening to the TRS based on the TCI state switch (as described above). When to switch between repeaters to listen to the TRS may be affected by one or more factors, such as fading or delay when switching the TCI state. As a result, the point at which the UE switches repeaters to obtain a TRS instance can be different from the point at which the UE switches repeaters to obtain the SSB.

[0136] In the case where the UE obtains SSB and TRS instances, the UE determines at least two sets of frequency errors in 1500 (e.g., group 1502 and 1504 or group 1502 and 1506). As shown, the UE's switching of repeaters for the SSB can occur before or after the switching of repeaters for the TRS. In some implementations, the UE uses the TRS to determine a frequency error that corresponds to the frequency error determined using the SSB (such as based on the UE's location or time when obtaining the TRS instance and the SSB). In this way, the UE determines an associated pair of frequency errors for the two sets of frequency errors (based on the UE's location or time when obtaining the SSB and the TRS instance).

[0137] The UE's switching between repeaters at a first time to listen for the SSB (the first time being different from the second time for listening for the TRS) can result in a divergence between the frequency error generated using the SSB and the frequency error generated using the TRS. For example, if the UE generates the frequency error for group 1502 and the frequency error for group 1504, the magnitude of the difference between the corresponding pair of frequency errors at 250 meters (where the UE switches to a second repeater to obtain the TRS instance) increases from approximately 250 Hz (at 200 meters) to approximately 1500 Hz (at 250 meters). In another example, if the UE generates the frequency error for group 1502 and the frequency error for group 1506, the magnitude of the difference between the corresponding pair of frequency errors continues to increase from approximately 200 Hz (at 200 meters) to approximately 1000 Hz (at 400 meters).

[0138] In some implementations, the difference between corresponding frequency errors (also referred to as frequency error difference) can be used to identify whether a wireless communication device is in an HST scenario. As used herein, the frequency error difference can refer to the magnitude of the difference between the frequency error generated using an SSB and the corresponding frequency error generated using a TRS instance corresponding to the SSB. For example, for groups of frequency errors 1502 and 1506 determined by a UE, the frequency error difference at 200 meters can be approximately 200 Hz (the absolute value of -450 Hz minus -650 Hz), the frequency error difference at 250 meters can be approximately 400 Hz (the absolute value of -350 Hz minus -750 Hz), the frequency error difference at 300 meters can be approximately 550 Hz (the absolute value of -200 Hz minus -750 Hz), and so on. Although examples of generating the frequency error difference are provided, the frequency error difference can be generated in any suitable manner (such as the difference between the average of a first group of frequency errors and one or more frequency errors in a second group of frequency errors, using the median of the frequency errors when determining the difference, determining when a curve for one group of frequency errors crosses a curve for another group of frequency errors, etc.). When determining that the wireless communication device is in an HST scenario, the wireless communication device can periodically determine the frequency error difference and determine whether the frequency error difference is greater than a frequency threshold. The frequency error difference being greater than the frequency threshold can indicate that the wireless communication device is in an HST scenario.

[0139] Figure 16 FIG. shows a flowchart depicting an example operation 1600 for identifying whether a wireless communication device is in an HST scenario based on a frequency error difference. Operation 1600 can be performed by a device in the wireless communication device. The wireless communication device can be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in Figure 5 UE 580 or 590 in Figure 6 ), or can be included in a UE. In some implementations, operation 1600 can be performed in addition to

[0140] At 1602, the wireless communication device receives a first SSB at a first time. In some implementations, the first time is when the wireless communication device is active (such as before the wireless communication device identifies that the wireless communication device is in an HST scenario). At 1604, the wireless communication device receives a first TRS instance associated with the first time. For example, the wireless communication device may obtain the first TRS instance at approximately the same time as the SSB. In some implementations of step 1604, "approximately simultaneously" may refer to the TRS instance (from multiple TRS instances) obtained at the time closest to obtaining the SSB. The SSB and the TRS instance may come from the same repeater or from different repeaters. For example, the SSB may come from the repeater associated with the strongest signal received by the wireless communication device, and the TRS instance may come from the repeater associated with the current TCI state used by the wireless communication device to monitor the TRS. The strongest signal and the TCI state may be associated with the same repeater, or the strongest signal may be associated with one repeater while the TCI state is associated with a different repeater.

[0141] At 1606, the wireless communication device generates a frequency error (which may be referred to as the first SSB frequency error) using the first SSB via one or more FTLs. At 1608, the wireless communication device generates a frequency error (which may be referred to as the first TRS frequency error) using the first TRS instance via one or more FTLs. Determining each frequency error may be as described above. At 1610, the wireless communication device generates a frequency error difference between the first SSB frequency error and the first TRS frequency error. In Figure 6 an example implementation of step 602 of operation 600 in, the wireless communication device may use the frequency error difference to determine whether the wireless communication device is in an HST scenario.

[0142] In some implementations, the wireless communication device identifying whether the wireless communication device is in an HST scenario includes: identifying whether the frequency error difference is greater than a frequency threshold. If the wireless communication device uses only one frequency error difference to identify whether the wireless communication device is in an HST scenario, then the frequency error difference being greater than the frequency threshold may indicate that the wireless communication device is in an HST scenario. Similar to Figures 11 - 14 the frequency threshold for the instantaneous frequency error in, any suitable frequency threshold may be used to attempt to indicate that the wireless communication device is in an HST scenario. For example, the frequency threshold may be 400 Hz, 600 Hz, or any other suitable number for the frequency error difference. The frequency threshold may be static or dynamic, or the frequency threshold may be set or adjusted by the device manufacturer, software, firmware, user, set or adjusted based on previous use or frequency error measurements, and so on.

[0143] Similar to as referenced above Figure 11And Figure 12 As described for the instantaneous frequency error, a wireless communication device can determine how many frequency error differences generated by the wireless communication device during a period are greater than a frequency threshold. The number of frequency error differences greater than the frequency threshold can indicate the number of repeater handovers during that period. If the number of frequency error differences greater than the frequency threshold during that period is greater than a threshold number, the wireless communication device can identify that the wireless communication device is in an HST scenario. If the number is not greater than the threshold number, the wireless communication device can identify that the wireless communication device is not in an HST scenario.

[0144] Figure 17 A flowchart showing an example operation 1700 for identifying whether a wireless communication device is in an HST scenario based on the number of frequency error differences is shown. Operation 1700 can be performed by a device in the wireless communication device. The wireless communication device can be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in, or Figure 5 UE 580 or 590 in), or can be included in a UE. In some implementations, in addition to Figure 16 operation 1600 in, operation 1700 can also be performed.

[0145] At 1702, the wireless communication device receives a plurality of SSBs in a first period. Returning to reference Figure 16 , the plurality of SSBs includes a first SSB, and the first period includes the first time from step 1602. For example, the wireless communication device can listen for and receive SSBs periodically transmitted by one or more repeaters or BSs. At 1704, the wireless communication device also receives a plurality of TRS instances in the first period. Returning to reference Figure 16, multiple TRS instances include the first TRS instance from step 1604. Additionally, each TRS instance among the multiple TRS instances is associated with an SSB among the multiple SSBs. For example, the TRS instance associated with an SSB can be the TRS example that is temporally closest to the SSB obtained by the wireless communication device. In this way, there are multiple pairs of associated SSBs and TRS instances. In some implementations, the number of TRS instances can be equal to the number of SSBs obtained, such that the number of pairs of associated SSBs and TRS instances is equal to the number of SSBs. In some implementations, the number of TRS instances can be less than the number of SSBs obtained. For example, the wireless communication device can receive SSBs from multiple repeaters while receiving TRS instances from only one repeater. In this way, the pairs of associated SSBs and TRS instances may not include all the SSBs received during the first time period. In some implementations, the multiple SSBs can be a part of all the SSBs obtained during the first time period, where each SSB among the multiple SSBs is associated with the obtained TRS instance.

[0146] At 1706, the wireless communication device generates an SSB frequency error for each SSB among the multiple SSBs through one or more FTLs. At 1708, the wireless communication device generates a TRS frequency error for each TRS instance among the multiple TRS instances through one or more FTLs. At 1710, the wireless communication device generates a frequency error difference for each pair of associated SSB and TRS instance, where the frequency error difference is between the SSB frequency error (1706) generated for the SSB and the TRS frequency error (1708) generated for the TRS instance. Return reference Figure 6 , identifying whether the wireless communication device is in an HST scenario can include: identifying whether the number of frequency error differences greater than the frequency threshold is greater than the threshold number defined for the HST scenario. For example, return reference Figure 15 , if the threshold number is 3, group 1502 indicates the SSB frequency error generated from the received SSBs, and group 1504 indicates the TRS frequency error generated from the received TRS instances, then the repeater handover results in a crossing event between the lines of groups 1502 and 1504 at the 250m position of the UE. In this way, the next pair of associated SSB and TRS instance after the handover is associated with a frequency error difference greater than the frequency threshold (thus indicating a handover). The number of frequency error differences greater than the frequency threshold during a time period being greater than 3 can indicate more than 3 handovers between repeaters or BSs during that time period. In this way, the threshold number can be used to distinguish the movement of the wireless communication device for the HST scenario from other movements not associated with the HST scenario.

[0147] Figure 18 FIG. 1800 is a flowchart depicting another example operation for identifying whether a wireless communication device is in an HST scenario based on the number of frequency error differences. Operation 1800 may be performed by means in a wireless communication device. The wireless communication device may be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in, or Figure 5 UE 580 or 590 in Figure 17 ), or may be included in a UE. In some implementations, operation 1800 may be an example implementation of operation 1700 in

[0148] At 1802, the wireless communication device obtains a plurality of SSBs in a first time period. In some implementations, the plurality of SSBs may include a first SSB. At 1804, the wireless communication device also obtains a plurality of TRS instances in the first time period. In some implementations, the plurality of TRS instances may include a first TRS instance. Each TRS instance of the plurality of TRS instances may be associated with an SSB of the plurality of SSBs.

[0149] At 1806, the wireless communication device determines an SSB frequency error for each SSB of the plurality of SSBs via one or more FTLs. At 1808, the wireless communication device determines a TRS frequency error for each TRS instance of the plurality of TRS instances via one or more FTLs. Determining each frequency error may be as described above. In the case where each TRS instance is associated with an SSB, each TRS frequency error is associated with the SSB frequency error. At 1810, the wireless communication device determines a frequency error difference between the SSB frequency error and the TRS frequency error for each pair of associated SSB and TRS instances. In this way, the wireless communication device may determine a sequence of frequency error differences over time. For example, referring back to Figure 15 , the length of the time period may correspond to the UE moving 450 meters (as in depiction 1500), and the wireless communication device may determine a sequence of instantaneous frequency errors based on the corresponding SSB frequency errors and TRS frequency errors within that time period.

[0150] Referring back to Figure 18 , at 1808, the wireless communication device determines whether the frequency error difference is greater than a frequency threshold for each frequency error difference. For example, referring back to Figure 15 , the UE may determine whether each frequency error difference determined for the UE moving 450 meters is greater than the frequency threshold. For example, each time a frequency error difference is determined over time, the frequency error difference is compared with the frequency threshold.

[0151] At decision block 1814, the wireless communication device can determine whether the number of frequency error differences determined to be greater than the frequency threshold is greater than a threshold number (such as described above). If the number is not greater than the threshold number, the wireless communication device can determine that the wireless communication device is not in an HST scenario (1816). In some implementations, if the number is not greater than the threshold number, the wireless communication device is configured to use the SSB obtained during CDRx to generate a frequency error and determine the communication frequency (instead of using the TRS). In this way, the wireless communication device can prevent listening to the TRS during CDRx (such as allowing the wireless communication device to remain in a low-power state for a longer time during the DRx cycle).

[0152] Returning to reference decision block 1814, if the number is greater than the threshold number, the wireless communication device can determine that the wireless communication device is in an HST scenario (1818). In some implementations, if the number is greater than the threshold number, the wireless communication device is configured to listen to the TRS during CDRx and obtain an instance of the TRS to generate a frequency error and determine the communication frequency (instead of using the obtained SSB).

[0153] In a specific example of operation 1800, the frequency threshold can be 600 Hz, the threshold number can be 1, and the time period can be 5 seconds. In this way, the parameters can be configured such that the wireless communication device attempts to determine that the repeater is switched two or more times during a 5-second period to identify that the wireless communication device is in an HST scenario. However, as mentioned herein, any suitable parameters can be used to identify that the wireless communication device is in an HST scenario (or otherwise listen to the TRS during CDRx). For example, any suitable time period, frequency threshold, or threshold number can be used to identify whether the wireless communication device is to listen to the TRS during CDRx.

[0154] In the case where the wireless communication device is identified as being in an HST scenario, the wireless communication device is configured to: obtain an instance of the TRS whether the UE is in an active state or the UE is in an idle state (such as during CDRx). In this way, the UE can continue to determine the frequency error difference and whether each frequency error difference is greater than the threshold. The comparison of the frequency error difference with the threshold can be used to determine whether the wireless communication device remains in the HST scenario over time.

[0155] In some implementations, as long as one or more frequency error differences remain above a frequency threshold over time, the wireless communication device remains configured to listen for TRS during CDRx (referred to as the wireless communication device still being in the HST scenario). For example, once the wireless communication device is configured to listen for TRS during CDRx when the wireless communication device is in the HST scenario, the wireless communication device can determine whether the number of frequency error differences greater than a second frequency threshold within a second time period is greater than a second threshold number.

[0156] Return to the reference for the specific example Figure 15 , if it has been determined that the UE is in the HST scenario before the UE starts moving from 0 meters to 450 meters in depiction 1500, it can be determined whether the UE is still in the HST scenario based on determining that the number of frequency error differences greater than the second frequency threshold is higher than the second threshold number. The second frequency threshold used to determine whether the UE is still in the HST scenario can be the same as or different from the above-mentioned frequency threshold used to determine that the UE is in the HST scenario. The second threshold number used to determine whether the UE is still in the HST scenario can be the same as or different from the above-mentioned threshold number used to determine whether the UE is in the HST scenario. The second time period used to determine whether the UE is still in the HST scenario can be the same as or different from the above-mentioned time period used to determine whether the UE is in the HST scenario. For example, the second threshold number (used to determine whether the UE is still in the HST scenario) can be less than the threshold number previously used to determine that the UE is in the HST scenario. In this way, remaining in the HST scenario (and thus being configured to listen for TRS during CDRx) can be easier than when first determining that the UE is in the HST scenario. In another example, the second threshold number can be the same as the previously used threshold number. In another example, the second time period used to determine whether the UE is still in the HST scenario can be longer than the time period initially used to determine that the UE is in the HST scenario. In this way, the second time period can be of sufficient length to compensate for possible stops and pauses during the UE's movement. For example, the second time period can have sufficient length to accommodate the HST stopping at a station or briefly decelerating (e.g., for construction, emergencies, for passengers to board and alight, etc.).

[0157] In some implementations, if all the parameters when determining whether the wireless communication device is still in the HST scenario are the same as the parameters used when first determining that the wireless communication device is in the HST scenario, the operation for determining whether the UE is still in the HST scenario can be the same as Figure 17 the example operation 1700 in Figure 18 or the example operation 1800 in Figure 13or Figure 14 similar to that described for the instantaneous frequency error.

[0158] Figure 19 A flowchart showing an example operation 1900 depicting identifying whether a wireless communication device is still in an HST scenario based on the number of frequency error differences. Operation 1900 can be performed by means in the wireless communication device. The wireless communication device can be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in, or Figure 5 UE580 or 590 in), or can be included in the UE. In some implementations, in addition to Figure 17 operation 1700 in Figure 18 or operation 1800 in, operation 1900 can also be performed. It should be noted that example operation 1900 can be similar to Figure 17 example operation 1700 in for identifying when a wireless communication device is initially in an HST scenario.

[0159] At 1902, when the wireless communication device is in an HST scenario, the wireless communication device receives a second plurality of SSBs in a second time period. At 1904, the wireless communication device also receives a second plurality of TRS instances in the second time period. Each TRS instance in the second plurality of TRS instances is associated with an SSB in the second plurality of SSBs. At 1906, the wireless communication device generates an SSB frequency error for each SSB in the second plurality of SSBs through one or more FTLs. At 1908, the wireless communication device also generates a TRS frequency error for each TRS instance in the second plurality of TRS instances through one or more FTLs. At 1910, the wireless communication device generates a frequency error difference between the SSB frequency error generated for the SSB and the TRS frequency error generated for the TRS instance for each pair of associated SSB and TRS instance from the second plurality of SSBs and the second plurality of TRS instances.

[0160] At 1912, the wireless communication device identifies whether the wireless communication device is no longer in an HST scenario. Identifying whether the wireless communication device is no longer in an HST scenario includes: identifying whether the number of frequency error differences greater than a second frequency threshold generated for the second plurality of SSBs and the second plurality of TRS instances is less than a second threshold number defined for the HST scenario (such as similar to Figure 17 step 1710 in

[0161] Figure 20FIG. 2000 is a flowchart depicting another example operation 2000 for identifying whether a wireless communication device is still in an HST scenario based on a quantity of frequency error differences. Operation 2000 may be performed by circuitry in a wireless communication device. The wireless communication device may be a UE (such as UE 104 in Figure 1 UE 350 in Figure 3 UE 480 in Figure 4 or UE 580 or 590 in Figure 5 ), or may be included in a UE. In some implementations, operation 2000 is an example implementation of operation 1900 in Figure 19 Note that example operation 2000 may be similar to example operation 1800 in Figure 18 for identifying when a wireless communication device was initially in an HST scenario.

[0162] At 2002, after determining that the wireless communication device is in an HST scenario, the wireless communication device obtains a second plurality of SSBs during a second time period. At 2004, the wireless communication device obtains a second plurality of TRS instances during the second time period. Similar to step 1804 in Figure 18 each TRS instance in the second plurality of TRS instances is associated with an SSB in the second plurality of SSBs. At 2006, the wireless communication device determines an SSB frequency error for each SSB in the second plurality of SSBs via one or more FTLs. At 2008, the wireless communication device also determines a TRS frequency error for each TRS instance in the second plurality of TRS instances via one or more FTLs. Since each TRS instance is associated with an SSB, each TRS frequency error is associated with an SSB frequency error.

[0163] At 2010, the wireless communication device determines a frequency error difference between the SSB frequency error and the TRS frequency error for each pair of associated SSB and TRS instances. At 2012, the wireless communication device determines whether each frequency error difference is greater than a second frequency threshold.

[0164] At decision box 2014, the wireless communication device determines whether the number of frequency error differences determined to be greater than the second frequency threshold is greater than the second threshold number. If the number is not greater than the second threshold number, the wireless communication device identifies that the wireless communication device is no longer in an HST scenario (2016). In this way, the wireless communication device can revert to tracking using the SSB obtained during CDRx. In some implementations, when the wireless communication device is no longer in an HST scenario, the wireless communication device can prevent listening to TRS during CDRx. If the number is greater than the second threshold number, the wireless communication device identifies that the wireless communication device is still in an HST scenario (2018). In this way, the wireless communication device is still configured to listen to TRS during CDRx.

[0165] As described above, one or more of the second time period, the second frequency threshold, or the second threshold quantity used in example operation 1900 or example operation 2000 may be used in conjunction with Figure 17 Example operation 1700 or Figure 18 The time period, frequency threshold or number of thresholds used in the example operation 1800 in can be the same (or different). In this way, entering the HST scenario can have the same or different constraints as exiting the HST scenario. As described above, "time period" as used herein can refer to a moving time window, overlapping or non-overlapping time blocks, or any other appropriate time measurement. In this way, determining whether the wireless communication device is in the HST scenario or determining whether the wireless communication device is still in the HST scenario can be based on the frequency error determined during the moving time window, during the fixed time block, or during any other appropriate measurement of the time period. As described above, the parameter can be any appropriate parameter, and the present disclosure is not limited to a specific time period length, a specific frequency threshold, or a specific number of thresholds.

[0166] As reference Figures 17 - 20 As described, some implementations for determining whether a wireless communication device is to monitor TRS during CDRx include: identifying whether the number of frequency error differences greater than a frequency threshold over a period of time is greater than a threshold number. However, in general, identifying whether a wireless communication device is to monitor TRS during CDRx (e.g., when the wireless communication device is in an HST scenario) can be based on whether the corresponding frequency error diverges over time. As described above with reference to Figure 15As mentioned, the divergence of the frequency error may be rapid (e.g., as indicated by the large divergence of the lines associated with groups 1502 and 1504, for which the SSB switching repeater is after the TRS switching repeater). In some other cases, the divergence of the frequency error over time may be slower (e.g., as indicated by the slowly increasing divergence between the lines associated with groups 1502 and 1506, for which the SSB switching repeater is before the TRS switching repeater). In both of the above cases, the frequency error diverges over time. The wireless communication device can use any suitable means to measure the divergence over time (also referred to as the trajectory of the frequency error difference) to identify whether the wireless communication device is in an HST scenario. In some implementations, the wireless communication device can use any of the operations described above with reference to Figures 17 - 20 to determine the trajectory of the difference. In some implementations, the wireless communication device can determine the moving average of the frequency error difference over time, determine the rate of increase of the frequency error difference over time, or use any other suitable means to measure the divergence of the frequency error.

[0167] Figure 21 FIG. shows a flowchart depicting example operation 2100 for identifying whether a wireless communication device is in an HST scenario based on the divergence of the frequency error over time. Operation 2100 can be performed by a device in the wireless communication device. The wireless communication device can be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in, or Figure 5 UE580 or 590 in Figure 16 ), or can be included in a UE. In some implementations, example operation 2100 can be supplementary to example operation 1600 in

[0168] At 2102, the wireless communication device receives a second SSB at a second time. In some implementations, the second time is at Figure 16Before the first time associated with the first SSB received in step 1602 of operation 1600 in. At 2104, the wireless communication device obtains a second TRS instance associated with a second time. At 2106, the wireless communication device uses the second SSB to generate a second SSB frequency error through one or more FTLs. At 2108, the wireless communication device uses the second TRS instance to generate a second TRS frequency error through one or more FTLs. At 2110, the wireless communication device generates a second frequency error difference between the second SSB frequency error and the second TRS frequency error. In this way, the wireless communication device determines a second frequency error difference for the frequency error at the second time and a first frequency error difference for the frequency error at the first time (from Figure 16 operation 1600 in). Identifying whether the wireless communication device is in an HST scenario includes: using the frequency error difference and the second frequency error difference to identify whether the frequency error difference is increasing over time. For example, if the first time is after the second time, the wireless communication device can determine whether the first frequency error difference is greater than the second frequency error difference, or otherwise the frequency error difference increases over time. Although operation 2100 (in combination with operation 1600) describes the wireless communication device using two frequency error differences to identify whether the frequency error difference is increasing over time and whether the wireless communication device is in an HST scenario, any appropriate number of frequency error differences can be used to measure the divergence of the frequency error difference over time (e.g., the frequency error difference increases by more than x differences).

[0169] Identifying when the wireless communication device is no longer in an HST scenario can be any appropriate operation, such as any of the examples provided above for identifying whether the wireless communication device is no longer in an HST scenario, or based on the frequency error difference converging over time or no longer diverging over time.

[0170] For the above example, it is not necessary to use each TRS instance obtained by the wireless communication device to determine the frequency error. Similarly, it is not necessary to use each SSB obtained by the wireless communication device to determine the frequency error. In this way, the wireless communication device may obtain more SSB and TRS instances compared to the SSB or TRS instances used to determine the instantaneous frequency error or frequency error difference. As a supplement or alternative, although the frequency error is described as being generated using an SSB or TRS instance, the FTL can receive multiple SSBs or multiple TRS instances over time for tracking.

[0171] The above example that describes identifying whether a wireless communication device is in an HST scenario refers to a sequence of frequency errors determined by the wireless communication device. However, identifying whether a wireless communication device is in an HST scenario can be based on measurements different from frequency error determination. As described above, whether the wireless communication device determines to listen for TRS during CDRx can be based on whether the UE is moving at a rate that causes a handover between repeaters or BSs when traveling through the coverage area of the network. The UE moving faster than a speed threshold or accelerating faster than an acceleration threshold can be associated with the UE being in an HST scenario. For example, the UE is in HST or in a car traveling along a highway, such that the UE is to listen for TRS during CDRx.

[0172] The UE can include or be coupled to one or more sensors for determining the speed or acceleration of the UE. For example, the UE can include an accelerometer or a motion sensor to determine the acceleration or speed of the UE, or the UE can use Wi-Fi positioning or GPS positioning to determine the acceleration or speed of the UE. In some implementations, the UE determines whether the speed or acceleration is greater than a threshold, which can indicate that the UE is in an HST scenario.

[0173] Figure 22 A flowchart of an example operation 2200 for determining whether a wireless communication device is in an HST scenario based on the speed or acceleration of the device is shown. Operation 2200 can be performed by means of a wireless communication device. The wireless communication device can be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in, or Figure 5 UE 580 or 590 in

[0174] At 2202, the UE obtains one or more measurements from one or more sensors for the UE. At 2204, the UE determines the speed or acceleration of the UE based on the one or more measurements. For example, the UE may periodically obtain one or more measurements from a motion sensor to determine the speed or acceleration of the UE. In another example, the UE may periodically (based on signals from multiple GPS satellites) obtain information from a GPS receiver. The UE may use this information to determine the geographical location of the UE over time, and may use the difference in geographical location over time to determine the speed or acceleration of the UE. Wi-Fi positioning or other wireless positioning may also be used to determine the location information over time, and the UE may determine the speed or acceleration based on this location information. At 2206, the UE determines whether the speed or acceleration is greater than a first threshold. The first threshold may be any suitable threshold, may be fixed or adjustable, and may be determined in any suitable manner. In some implementations, the first threshold may be a speed threshold for differentiating between a UE on an HST and a UE not on an HST. For example, the first threshold may be 200 kph or 300 kph.

[0175] If the UE is in an HST scenario, the UE may be configured to listen for TRS during CDRx. Determining whether the UE remains in the HST scenario (and the UE will continue to listen for TRS during CDRx) may also be based on whether the speed remains above the speed threshold. For example, when the user gets off the HST (or the HST reaches its final destination), the UE is no longer moving such that handover between repeaters of the BS is not required. Determining whether the speed of the UE remains above the speed threshold may indicate whether the UE is exiting the HST scenario.

[0176] Figure 23 A flowchart depicting an example operation 2300 for determining whether a wireless communication device is no longer in an HST scenario based on the speed of the wireless communication device is shown. Operation 2300 may be performed by means in the wireless communication device. The wireless communication device may be a UE (such as Figure 1 UE 104 in Figure 3 UE 350 in Figure 4 UE 480 in Figure 5 UE 580 or 590 in

[0177] At 2302, during a period when the UE is in an HST scenario, the UE obtains additional measurements from one or more sensors. The additional measurements may be related to those referred to above in Figure 22is similar to the measurement described in step 2202. At 2304, the UE determines whether the speed of the UE remains less than a speed threshold during the time period based on the additional measurement. In this example, a speed less than the speed threshold within a time period may indicate that the UE is no longer moving at high speed. For example, if the HST stops for an extended amount of time (greater than the time period), or the user stands on the train platform for more than the time period, the UE may not be moving such that a handover between repeaters of the BS is required. If the speed temporarily drops below the speed threshold (within a time length less than the time period), the UE may still be in the HST scenario. In this way, the time period can be used to compensate for scenarios where the HST decelerates (e.g., for construction, icy track conditions, curves in the track, etc.) without determining that the UE is no longer in the HST scenario. At 2306, the UE may determine that the UE is no longer in the HST scenario based on the speed of the UE remaining below the speed threshold during the time period. The time period can be any suitable time period, and the speed threshold can be any suitable speed threshold. The time period or the speed threshold can be fixed or variable, and can be determined by the device manufacturer, software, firmware, or the user, or can be determined or adjusted in any other suitable way in other aspects.

[0178] In some implementations, it can be determined whether the UE is in the HST scenario based on the location of the UE. For example, the network can be dedicated to the HST system (where UEs on the network are limited to users of the HST system), or the network can include BSs and repeaters located at specific locations on a highway system associated with vehicles (which travel at high speed such that a UE in one of those vehicles hands over between repeaters and BSs). The location of the HST system can be known (including the tracks and platforms of the HST system or the BSs and repeaters in a network dedicated to the HST system (which can be referred to as an HST network)), and the known geographical location can be associated with determining that the UE is in the HST scenario. For example, a geographical area can be geofenced or otherwise indicate to the UE that locations in the area are associated with the HST scenario. In some implementations, the UE can use a GPS receiver to determine whether the location of the UE is in a geofenced area associated with the HST scenario. If the UE is in a geofenced area associated with the HST scenario, the UE can be configured to listen for TRS during CDRx.

[0179] Figure 24 shows a flowchart of an example operation 2400 for determining whether a device is in an HST scenario based on the location of a wireless communication device. Operation 2400 can be performed by means in the wireless communication device. The wireless communication device can be a UE (e.g., Figure 1 UE 104 in Figure 3the UE 350 in Figure 4 the UE 480 in, or Figure 5 the UE 580 or 590 in), or may be included in a UE. In these examples, the wireless communication device is described as a UE, but any suitable wireless communication device may be used.

[0180] At 2402, the UE obtains one or more signals from a GPS receiver. At 2404, the UE determines the location of the UE based on the one or more signals from the GPS receiver. At 2406, the UE determines whether the location is within a region where a geofence is set for the HST. If the location is within the region where a geofence is set for the HST, it may be determined that the UE is in an HST scenario. In this way, the UE can be configured to listen for TRS during CDRx. If the location of the UE is not within the region where a geofence is set for the HST, the UE can use the SSB obtained during CDRx for tracking. In some other implementations, the UE can determine whether the UE is approaching the region or is otherwise on a trajectory to enter the region. In this way, the UE can predict whether the UE is about to enter an HST scenario.

[0181] Similar to using the location of the UE to determine whether the UE is in an HST scenario, the location of the UE can be used to determine whether the UE is no longer in an HST scenario. For example, if the UE determines that its location is no longer within the region where a geofence is set for the HST, the UE may no longer be in an HST scenario.

[0182] Figure 25 shows a flowchart depicting an example operation 2500 for determining that the device is no longer in an HST scenario based on the location of a wireless communication device. Operation 2500 may be performed by means in the wireless communication device. The wireless communication device may be a UE (such as, Figure 1 the UE 104 in Figure 3 the UE 350 in Figure 4 the UE 480 in, or Figure 5 the UE 580 or 590 in), or may be included in a UE. In these examples, the wireless communication device is described as a UE, but any suitable wireless communication device may be used.

[0183] At 2502, when the UE is in an HST scenario, the UE obtains one or more additional signals from a GPS receiver. At 2504, the UE determines a second location of the UE based on the one or more additional signals from the GPS receiver. At 2506, the UE determines that the second location is outside the area where a geofence is set for HST. At 2508, based on determining that the second location is outside the area where a geofence is set for HST, the UE determines that the UE is no longer in the HST scenario. If the UE remains in the area where a geofence is set for HST, the UE may remain configured to listen for TRS during CDRx. If the location of the UE is within the area where a geofence is set for HST, the UE may alternatively use the SSB obtained during CDRx for tracking. In some other implementations, the UE may determine whether the UE is approaching the boundary of the area or is otherwise on a trajectory to leave the area. In this way, the UE can predict whether the UE is about to exit the HST scenario.

[0184] Described are different example implementations for a UE to identify when to listen for TRS during CDRx or use the obtained SSB for tracking instead of listening for TRS during CDRx. In some aspects, the example implementations may be complementary to each other or may be alternatives to each other. For example, the speed of the UE can be used to verify that the UE is in an HST scenario based on a frequency error difference or an instantaneous frequency error. In another example, the instantaneous frequency error or the frequency error difference can initially be used to determine that the UE is in an HST scenario, and the speed of the UE being less than a threshold over a period of time can be used to determine that the UE is no longer in the HST scenario. Any of the above implementations or any suitable combination of the above multiple implementations can be used to determine whether the UE will be configured to listen for TRS during CDRx. As described, the UE is capable of selectively switching between listening for TRS during CDRx or preventing listening for TRS during CDRx. In this way, the UE can increase power and resource savings without sacrificing wireless performance.

[0185] Example implementations are described in the following numbered clauses:

[0186] 1. A wireless communication device, comprising:

[0187] A processing system configured to:

[0188] Identify whether the wireless communication device is in a high-speed train (HST) scenario; and

[0189] Generate a frequency error through one or more frequency tracking loops (FTL); and

[0190] An interface configured to:

[0191] When the wireless communication device is in the HST scenario, a tracking reference signal (TRS) is obtained during connected mode discontinuous reception (CDRx), wherein generating the frequency error by means of the one or more FTLs includes: when the wireless communication device is in the HST scenario, using the TRS.

[0192] 2. The wireless communication device according to clause 1, wherein:

[0193] The interface is configured to:

[0194] obtain a synchronization signal block (SSB) during CDRx; and

[0195] The processing system is configured to:

[0196] when the wireless communication device is not in the HST scenario, generate the frequency error by means of the one or more FTLs using the SSB.

[0197] 3. The wireless communication device according to one or more of clauses 1 - 2, wherein:

[0198] The interface is configured to:

[0199] when the wireless communication device is not in the HST scenario, prevent listening to the TRS during CDRx.

[0200] 4. The wireless communication device according to one or more of clauses 1 - 3, wherein:

[0201] The interface is configured to:

[0202] obtain a first instance of the TRS; and

[0203] obtain a second instance of the TRS; and

[0204] The processing system is configured to:

[0205] generate a first frequency error by means of the one or more FTLs using the first instance;

[0206] generate a second frequency error by means of the one or more FTLs using the second instance; and

[0207] generate an instantaneous frequency error using the first frequency error and the second frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the instantaneous frequency error is greater than a frequency threshold.

[0208] 5. The wireless communication device according to one or more of clauses 1-4, wherein the instantaneous frequency error is the difference between the first frequency error and the second frequency error.

[0209] 6. The wireless communication device according to one or more of clauses 1-4, wherein:

[0210] The interface is configured to:

[0211] Obtain a plurality of TRS instances in a first time period, wherein the plurality of TRS instances include the first instance and the second instance; and

[0212] The processing system is configured to:

[0213] Use the plurality of TRS instances to generate a plurality of instantaneous frequency errors, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the number of the plurality of instantaneous frequency errors greater than the frequency threshold is greater than the threshold number defined for the HST scenario.

[0214] 7. The wireless communication device according to one or more of clauses 1-6, wherein:

[0215] The interface is configured to:

[0216] When the wireless communication device is in the HST scenario, obtain a second plurality of TRS instances in a second time period; and

[0217] The processing system is configured to:

[0218] Use the second plurality of TRS instances to generate a second plurality of instantaneous frequency errors; and

[0219] Identifying whether the wireless communication device is no longer in the HST scenario includes identifying whether the number of the second plurality of instantaneous frequency errors greater than the second frequency threshold is less than the second threshold number defined for the HST scenario.

[0220] 8. The wireless communication device according to one or more of clauses 1-7, wherein:

[0221] The interface is configured to:

[0222] When the wireless communication device is no longer in the HST scenario, prevent listening to the TRS during CDRx.

[0223] 9. The wireless communication device according to one or more of clauses 1-8, wherein:

[0224] The interface is configured to:

[0225] Obtain a first SSB at a first time; and

[0226] Obtain a first TRS instance associated with the first time; and

[0227] The processing system is configured to:

[0228] Generate a first SSB frequency error using the first SSB via the one or more FTLs;

[0229] Generate a first TRS frequency error using the first TRS instance via the one or more FTLs; and

[0230] Generate a frequency error difference between the first SSB frequency error and the first TRS frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes using the frequency error difference.

[0231] 10. The wireless communication device according to one or more of clauses 1-9, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the frequency error difference is greater than a frequency threshold.

[0232] 11. The wireless communication device according to one or more of clauses 1-10, wherein:

[0233] The interface is configured to:

[0234] Obtain a plurality of SSBs in a first time period, wherein the plurality of SSBs includes the first SSB, and the first time period includes the first time; and

[0235] Obtain a plurality of TRS instances in the first time period, wherein the plurality of TRS instances includes the first TRS instance, and each TRS instance in the plurality of TRS instances is associated with an SSB in the plurality of SSBs; and

[0236] The processing system is configured to:

[0237] Generate an SSB frequency error for each SSB in the plurality of SSBs via the one or more FTLs;

[0238] Generate a TRS frequency error for each TRS instance in the plurality of TRS instances via the one or more FTLs; and

[0239] For each pair of associated SSB and TRS instances, generate a frequency error difference between the SSB frequency error generated for the SSB and the TRS frequency error generated for the TRS instance, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the number of frequency error differences greater than the frequency threshold is greater than the threshold number defined for the HST scenario.

[0240] 12. The wireless communication device according to one or more of clauses 1-11, wherein:

[0241] The interface is configured to:

[0242] When the wireless communication device is in the HST scenario, obtain a second plurality of SSBs in a second time period; and obtain a second plurality of TRS instances in the second time period, wherein each TRS instance in the second plurality of TRS instances is associated with an SSB in the second plurality of SSBs; and

[0243] The processing system is configured to:

[0244] Generate an SSB frequency error for each SSB in the second plurality of SSBs through the one or more FTLs;

[0245] Generate a TRS frequency error for each TRS instance in the second plurality of TRS instances through the one or more FTLs; and

[0246] For each pair of associated SSB and TRS instances from the second plurality of SSBs and the second plurality of TRS instances, generate a frequency error difference between the SSB frequency error generated for the SSB and the TRS frequency error generated for the TRS instance; and

[0247] Identifying whether the wireless communication device is no longer in the HST scenario includes identifying whether the number of the frequency error differences greater than a second frequency threshold generated for the second plurality of SSBs and the second plurality of TRS instances is less than a second threshold number defined for the HST scenario.

[0248] 13. The wireless communication device according to one or more of clauses 1-12, wherein:

[0249] The interface is configured to:

[0250] When the wireless communication device is no longer in the HST scenario, prevent listening to the TRS during CDRx.

[0251] 14. The wireless communication device according to one or more of clauses 1-13, wherein:

[0252] The interface is configured to:

[0253] Obtain a second SSB at a second time; and

[0254] Obtain a second TRS instance associated with the second time; and

[0255] The processing system is configured to:

[0256] Generate a second SSB frequency error using the second SSB through the one or more FTLs;

[0257] Generate a second TRS frequency error using the second TRS instance through the one or more FTLs; and

[0258] Generate a second frequency error difference between the second SSB frequency error and the second TRS frequency error, wherein,

[0259] Identifying whether the wireless communication device is in the HST scenario includes: using the frequency error difference and the second frequency error difference to identify whether the frequency error difference is increasing over time.

[0260] 15. A method performed by a device in a wireless communication device, comprising:

[0261] Identifying whether the wireless communication device is in a high-speed train (HST) scenario;

[0262] When the wireless communication device is in the HST scenario, receive a tracking reference signal (TRS) during connected mode discontinuous reception (CDRx); and

[0263] When the wireless communication device is in the HST scenario, generate a frequency error using the TRS through one or more frequency tracking loops (FTL).

[0264] 16. The method according to clause 15, further comprising:

[0265] Receive a synchronization signal block (SSB) during CDRx; and

[0266] When the wireless communication device is not in the HST scenario, generate the frequency error using the SSB through the one or more FTLs.

[0267] 17. The method according to one or more of clauses 15 - 16 further includes: when the wireless communication device is not in the HST scenario, preventing listening to the TRS during CDRx.

[0268] 18. The method according to one or more of clauses 15 - 17 further includes:

[0269] Receiving a first instance of the TRS;

[0270] Receiving a second instance of the TRS;

[0271] Using the first instance to generate a first frequency error through the one or more FTLs;

[0272] Using the second instance to generate a second frequency error through the one or more FTLs; and

[0273] Using the first frequency error and the second frequency error to generate an instantaneous frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the instantaneous frequency error is greater than a frequency threshold.

[0274] 19. The method according to one or more of clauses 15 - 18, wherein the instantaneous frequency error is the difference between the first frequency error and the second frequency error.

[0275] 20. The method according to one or more of clauses 15 - 19 further includes:

[0276] Receiving a plurality of TRS instances in a first time period, wherein the plurality of TRS instances includes the first instance and the second instance; and

[0277] Using the plurality of TRS instances to generate a plurality of instantaneous frequency errors, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the number of the plurality of instantaneous frequency errors that is greater than the frequency threshold is greater than a threshold number defined for the HST scenario.

[0278] 21. The method according to one or more of clauses 15 - 20 further includes:

[0279] When the wireless communication device is in the HST scenario, obtaining a second plurality of TRS instances in a second time period;

[0280] Using the second plurality of TRS instances to generate a second plurality of instantaneous frequency errors; and

[0281] Identifying whether the wireless communication device is no longer in the HST scenario includes: identifying whether the number of the second plurality of instantaneous frequency errors that are greater than a second frequency threshold is less than a second threshold number defined for the HST scenario.

[0282] 22. The method according to one or more of clauses 15 - 21 further includes: when the wireless communication device is no longer in the HST scenario, preventing listening to the TRS during CDRx.

[0283] 23. The method according to one or more of clauses 15 - 22 further includes:

[0284] Receiving a first SSB at a first time;

[0285] Receiving a first TRS instance associated with the first time;

[0286] Generating a first SSB frequency error using the first SSB through the one or more FTLs;

[0287] Generating a first TRS frequency error using the first TRS instance through the one or more FTLs; and

[0288] Generating a frequency error difference between the first SSB frequency error and the first TRS frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes: using the frequency error difference.

[0289] 24. The method according to one or more of clauses 15 - 23, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the frequency error difference is greater than a frequency threshold.

[0290] 25. The method according to one or more of clauses 15 - 24 further includes:

[0291] Receiving a plurality of SSBs in a first time period, wherein the plurality of SSBs includes the first SSB, and the first time period includes the first time;

[0292] Obtaining a plurality of TRS instances in the first time period, wherein the plurality of TRS instances includes the first TRS instance, and each TRS instance in the plurality of TRS instances is associated with an SSB in the plurality of SSBs; and

[0293] Generating an SSB frequency error for each SSB in the plurality of SSBs through the one or more FTLs;

[0294] Generate a TRS frequency error for each of the plurality of TRS instances via the one or more FTLs; and

[0295] Generate a frequency error difference between the SSB frequency error generated for the SSB and the TRS frequency error generated for the TRS instance for each pair of associated SSB and TRS instance, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the number of frequency error differences greater than the frequency threshold is greater than the threshold number defined for the HST scenario.

[0296] 26. The method according to one or more of clauses 15 - 25, further comprising:

[0297] When the wireless communication device is in the HST scenario, obtain a second plurality of SSBs in a second time period;

[0298] Obtain a second plurality of TRS instances in the second time period, wherein each TRS instance in the second plurality of TRS instances is associated with an SSB in the second plurality of SSBs; and

[0299] Generate an SSB frequency error for each of the second plurality of SSBs via the one or more FTLs;

[0300] Generate a TRS frequency error for each of the second plurality of TRS instances via the one or more FTLs;

[0301] Generate a frequency error difference between the SSB frequency error generated for the SSB and the TRS frequency error generated for the TRS instance for each pair of associated SSB and TRS instance from the second plurality of SSBs and the second plurality of TRS instances; and

[0302] Identifying whether the wireless communication device is no longer in the HST scenario includes: identifying whether the number of the frequency error differences greater than a second frequency threshold generated for the second plurality of SSBs and the second plurality of TRS instances is less than a second threshold number defined for the HST scenario.

[0303] 27. The method according to one or more of clauses 15 - 26, further comprising: When the wireless communication device is no longer in the HST scenario, prevent listening to the TRS during CDRx.

[0304] 28. The method according to one or more of clauses 15 - 27, further comprising:

[0305] Receive a second SSB at a second time; and

[0306] Receive a second TRS instance associated with the second time; and

[0307] Generate a second SSB frequency error using the second SSB via the one or more FTLs;

[0308] Generate a second TRS frequency error using the second TRS instance via the one or more FTLs; and

[0309] Generate a second frequency error difference between the second SSB frequency error and the second TRS frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes: using the frequency error difference and the second frequency error difference to identify whether the frequency error difference is increasing over time.

[0310] Other implementation examples are described in the numbered clauses below:

[0311] 1. A method performed by apparatus in a wireless communication device, comprising:

[0312] Determine whether the wireless communication device is moving;

[0313] Based on determining that the wireless communication device is moving, obtain a tracking reference signal (TRS) during connected mode discontinuous reception (CDRx);

[0314] Determine a frequency error using the TRS via one or more frequency tracking loops (FTL); and

[0315] Determine a communication frequency based on the frequency error.

[0316] 2. The method according to clause 1, wherein:

[0317] Determining whether the wireless communication device is moving includes: determining whether the wireless communication device is in a high-speed train (HST) scenario; and

[0318] Obtaining the TRS during CDRx is based on determining that the wireless communication device is in the HST scenario.

[0319] 3. The method according to clause 2, further comprising:

[0320] Obtain a synchronization signal block (SSB) during CDRx; and

[0321] In response to determining that the wireless communication device is not in the HST scenario, determine the frequency error using the SSB via the one or more FTLs.

[0322] 4. The method according to clause 3 further includes: in response to determining that the wireless communication device is not in the HST scenario, preventing the TRS from being listened to during CDRx.

[0323] 5. The method according to clause 2 further includes:

[0324] obtaining a first instance of the TRS and a second instance of the TRS before determining whether the wireless communication device is in the HST scenario, where the second instance is obtained after the first instance;

[0325] using the first instance to determine a first frequency error through the one or more FTLs;

[0326] using the second instance to determine a second frequency error through the one or more FTLs;

[0327] determining an instantaneous frequency error for the second frequency error based on the first frequency error and the second frequency error; and

[0328] determining whether the instantaneous frequency error is greater than a frequency threshold, where determining whether the wireless communication device is in the HST scenario is based on whether the instantaneous frequency error is greater than the frequency threshold.

[0329] 6. The method according to clause 5, where the instantaneous frequency error is the difference between the first frequency error and the second frequency error.

[0330] 7. The method according to clause 5 further includes:

[0331] obtaining a plurality of TRS instances in a first time period, where the plurality of TRS instances includes the first instance and the second instance;

[0332] determining a plurality of instantaneous frequency errors according to the plurality of TRS instances; and

[0333] for each instantaneous frequency error, determining whether the instantaneous frequency error is greater than the frequency threshold, where determining whether the wireless communication device is in the HST scenario is based on whether the number of instantaneous frequency errors greater than the frequency threshold is greater than a threshold number defined for the HST scenario.

[0334] 8. The method according to clause 7 further includes:

[0335] obtaining a second plurality of TRS instances after determining that the wireless communication device is in the HST scenario and in a second time period;

[0336] Determine the second plurality of instantaneous frequency errors based on the second plurality of TRS instances;

[0337] For each of the second plurality of instantaneous frequency errors, determine whether the instantaneous frequency error is greater than a second frequency threshold; and

[0338] Based on the number of instantaneous frequency errors greater than the second frequency threshold for the second plurality of instantaneous frequency errors being less than a second threshold number defined for the HST scenario, determine that the wireless communication device is no longer in the HST scenario.

[0339] 9. The method according to clause 8, further comprising: in response to determining that the wireless communication device is no longer in the HST scenario, prevent listening to the TRS during CDRx.

[0340] 10. The method according to clause 8, wherein the length of the second time period is equal to the length of the first time period.

[0341] 11. The method according to clause 8, wherein the second frequency threshold is equal to the frequency threshold.

[0342] 12. The method according to clause 8, wherein the second threshold number defined for the HST scenario is equal to the threshold number defined for the HST scenario.

[0343] 13. The method according to clause 2, further comprising:

[0344] Before determining whether the wireless communication device is in the HST scenario, obtain a first SSB at a first time;

[0345] Obtain a first TRS instance associated with the first time;

[0346] Perform the following operations through the one or more FTLs:

[0347] Determine a first SSB frequency error based on the first SSB; and

[0348] Determine a first TRS frequency error based on the first TRS instance; and

[0349] Determine a frequency error difference between the first SSB frequency error and the first TRS frequency error, wherein determining whether the wireless communication device is in the HST scenario is based on the frequency error difference.

[0350] 14. The method according to clause 13 further includes: determining whether the frequency error difference is greater than a frequency threshold, wherein determining whether the wireless communication device is in the HST scenario is based on whether the frequency error difference is greater than the frequency threshold.

[0351] 15. The method according to clause 14 further includes:

[0352] Obtaining a plurality of SSBs in a first time period, wherein the plurality of SSBs includes the first SSB, and the first time period includes the first time;

[0353] Obtaining a plurality of TRS instances in the first time period, wherein the plurality of TRS instances includes the first TRS instance, and each TRS instance in the plurality of TRS instances is associated with an SSB in the plurality of SSBs;

[0354] Generating an SSB frequency error for each SSB in the plurality of SSBs through the one or more FTLs;

[0355] Generating a TRS frequency error for each TRS instance in the plurality of TRS instances through the one or more FTLs; and

[0356] Determining a frequency error difference between the SSB frequency error and the TRS frequency error for each pair of associated SSB and TRS instance; and

[0357] For each frequency error difference, determining whether the frequency error difference is greater than the frequency threshold, wherein determining whether the wireless communication device is in the HST scenario is based on whether the number of frequency error differences greater than the frequency threshold is greater than the threshold number defined for the HST scenario.

[0358] 16. The method according to clause 15 further includes:

[0359] After determining that the wireless communication device is in the HST scenario, obtaining a second plurality of SSBs in a second time period;

[0360] Obtaining a second plurality of TRS instances in the second time period, wherein each TRS instance in the second plurality of TRS instances is associated with an SSB in the second plurality of SSBs;

[0361] Determining an SSB frequency error for each SSB in the second plurality of SSBs through the one or more FTLs;

[0362] Determining a TRS frequency error for each TRS instance in the second plurality of TRS instances through the one or more FTLs;

[0363] For each pair of associated SSB and TRS instances from the second plurality of SSBs and the second plurality of TRS instances, determine a frequency error difference between the SSB frequency error and the TRS frequency error;

[0364] For each frequency error difference of the second plurality of SSBs and the second plurality of TRS instances, determine whether the frequency error difference is greater than a second frequency threshold; and

[0365] Based on the number of frequency error differences greater than the second frequency threshold for the second plurality of SSBs and the second plurality of TRSs being less than a second threshold number defined for the HST scenario, determine that the wireless communication device is no longer in the HST scenario.

[0366] 17. The method according to clause 16, further comprising: in response to determining that the wireless communication device is no longer in the HST scenario, prevent listening to the TRS during CDRx.

[0367] 18. The method according to clause 16, wherein the length of the second time period is equal to the length of the first time period.

[0368] 19. The method according to clause 16, wherein the second frequency threshold is equal to the frequency threshold.

[0369] 20. The method according to clause 16, wherein the second threshold number defined for the HST scenario is equal to the threshold number defined for the HST scenario.

[0370] 21. The method according to clause 13, further comprising:

[0371] Obtain a second SSB at a second time, wherein the second time is before the first time;

[0372] Obtain a second TRS instance associated with the second time;

[0373] Perform the following operations through the one or more FTLs:

[0374] Determine a second SSB frequency error based on the second SSB; and

[0375] Determine a second TRS frequency error based on the second TRS instance;

[0376] Determine a second frequency error difference between the second SSB frequency error and the second TRS frequency error; and

[0377] Determine whether the frequency error difference is increasing over time based on the first frequency error difference and the second frequency error difference, wherein determining whether the wireless communication device is in the HST scenario is based on determining whether the frequency error difference is increasing over time.

[0378] 22. The method according to clause 2 further includes:

[0379] Obtain one or more measurements from one or more sensors of the wireless communication device;

[0380] Determine the speed or acceleration of the wireless communication device based on the one or more measurements; and

[0381] Determine whether the speed or acceleration is greater than a first threshold, wherein determining whether the wireless communication device is in the HST scenario is based on whether the speed or acceleration is greater than the first threshold.

[0382] 23. The method according to clause 22 further includes:

[0383] Obtain additional measurements from the one or more sensors during a period when the wireless communication device is in the HST scenario;

[0384] Determine that the speed of the wireless communication device remains less than a speed threshold during the period based on the additional measurements; and

[0385] Based on the speed of the wireless communication device remaining below the speed threshold during the period, determine that the wireless communication device is no longer in the HST scenario.

[0386] 24. The method according to clause 23 further includes: in response to determining that the wireless communication device is no longer in the HST scenario, prevent listening to the TRS during CDRx.

[0387] 25. The method according to clause 23, wherein the speed threshold is equal to the first threshold.

[0388] 26. The method according to clause 2 further includes:

[0389] Obtain one or more signals from a Global Positioning System (GPS) receiver;

[0390] Determine the position of the wireless communication device based on the one or more signals from the GPS receiver; and

[0391] Determine whether the location is within an area where a geofence is set for the HST, wherein determining whether the wireless communication device is in the HST scenario is based on determining whether the location is within the area where the geofence is set for the HST.

[0392] 27. The method according to clause 26 further includes:

[0393] When the wireless communication device is in the HST scenario, obtain one or more additional signals from the GPS receiver;

[0394] Determine a second location of the wireless communication device based on the one or more additional signals from the GPS receiver;

[0395] Determine that the second location is outside the area where the geofence is set for the HST; and

[0396] Based on determining that the second location is outside the area where the geofence is set for the HST, determine that the wireless communication device is no longer in the HST scenario.

[0397] 28. The method according to clause 27 further includes: in response to determining that the wireless communication device is no longer in the HST scenario, prevent listening to the TRS during CDRx.

[0398] 29. A wireless communication device includes:

[0399] At least one modem;

[0400] At least one processor communicatively coupled to the at least one modem; and

[0401] At least one memory communicatively coupled to the at least one processor and storing processor-readable code, the processor-readable code being configured to perform the method according to any one of clauses 1-28 when executed by the at least one processor in combination with the at least one modem.

[0402] 30. A mobile station includes:

[0403] The wireless communication device according to clause 29;

[0404] At least one transceiver coupled to the at least one modem;

[0405] At least one antenna coupled to the at least one transceiver to wirelessly transmit signals output from the at least one transceiver and wirelessly receive signals for input to the at least one transceiver; and

[0406] A housing that includes at least a portion of the at least one modem, the at least one processor, the at least one memory, the at least one transceiver, and the at least one antenna.

[0407] As used herein, a phrase referring to "at least one" or "one or more" of a list of items means any combination of those items, including a single member. By way of example, "at least one of a, b, or c" and "one or more of a, b, or c" are intended to cover: a, b, c, a - b, a - c, b - c, and a - b - c.

[0408] The various illustrative logical, logical block, modules, circuits, and algorithmic processes described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. The interchangeability of hardware and software has been generally described in terms of functionality and is illustrated in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented as hardware or software depends upon the particular application and the design constraints imposed on the overall system.

[0409] The hardware and data processing apparatus for implementing the various illustrative logical, logical block, modules, and circuits described in connection with the aspects disclosed herein can be implemented or performed with a general - purpose single - chip or multi - chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field - programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The general - purpose processor can be a microprocessor, or any conventional processor, controller, micro - controller, or state machine. The processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, specific processes and methods can be performed by circuitry specific to a given function.

[0410] In one or more aspects, the described functionality can be implemented using hardware, digital electronic circuits, computer software, firmware (including the structures disclosed in this specification and structural equivalents thereof), or any combination thereof. Embodiments of the subject matter described in this specification can also be implemented as one or more computer programs (e.g., one or more modules of computer program instructions) encoded on a computer storage medium for execution by, or to control the operation of, a data processing apparatus.

[0411] If implemented in software, the functions can be stored on or transmitted via a computer-readable medium as one or more instructions or codes. The processes of the methods or algorithms disclosed herein can be implemented in processor-executable software modules that may reside on a computer-readable medium. The computer-readable medium includes both computer storage media and communication media, where the communication media includes any medium that can be enabled to transfer a computer program from one place to another. The storage media can be any available medium accessible by a computer. By way of example and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired program code in the form of instructions or data structures and that can be accessed by a computer. Additionally, any connection can be properly termed a computer-readable medium. As used herein, disk and optical disks include compact disk (CD), laser disk, optical disk, digital versatile disk (DVD), floppy disk, and Blu-ray disk, where disks typically reproduce data magnetically, while optical disks reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Further, the operations of a method or algorithm can reside as code and instructions in one or any combination or collection on a machine-readable medium and a computer-readable medium, which can be incorporated into a computer program product.

[0412] Various modifications to the embodiments described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of this disclosure. For example, the steps described in different operations can be performed in a different order or concurrently, and one or more instances of the steps can be executed for that operation. Thus, the claims are not intended to be limited to the embodiments shown herein but are to be accorded the widest scope consistent with this disclosure, the principles disclosed herein, and the novel features.

Claims

1. A wireless communication device, comprising: an interface configured to: obtain a first instance of a Tracking Reference Signal (TRS); and obtain a second instance of the TRS; and a processing system configured to: identify whether the wireless communication device is in a High-Speed Train (HST) scenario; and generate a frequency error through one or more Frequency Tracking Loops (FTLs); generate a first frequency error using the first instance through the one or more FTLs; generate a second frequency error using the second instance through the one or more FTLs; and generate an instantaneous frequency error using the first frequency error and the second frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the instantaneous frequency error is greater than a frequency threshold; the interface is further configured to: obtain the TRS during Connected Mode Discontinuous Reception (CDRx) when the wireless communication device is in the HST scenario, wherein generating the frequency error through the one or more FTLs includes: using the TRS when the wireless communication device is in the HST scenario.

2. The wireless communication device according to claim 1, wherein: the interface is configured to: obtain a Synchronization Signal Block (SSB) during CDRx; and the processing system is configured to: generate the frequency error using the SSB through the one or more FTLs when the wireless communication device is not in the HST scenario.

3. The wireless communication device according to claim 2, wherein: the interface is configured to: prevent listening to the TRS during CDRx when the wireless communication device is not in the HST scenario.

4. The wireless communication device according to claim 1, wherein, The instantaneous frequency error is the difference between the first frequency error and the second frequency error.

5. The wireless communication device according to claim 1, wherein: the interface is configured to: obtain a plurality of TRS instances in a first time period, wherein the plurality of TRS instances includes the first instance and the second instance; and the processing system is configured to: generate a plurality of instantaneous frequency errors using the plurality of TRS instances, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the number of the plurality of instantaneous frequency errors greater than the frequency threshold is greater than a threshold number defined for the HST scenario.

6. The wireless communication device according to claim 5, wherein: the interface is configured to: obtain a second plurality of TRS instances in a second time period when the wireless communication device is in the HST scenario; and the processing system is configured to: generate a second plurality of instantaneous frequency errors using the second plurality of TRS instances; and identify whether the wireless communication device is no longer in the HST scenario, including identifying whether the number of the second plurality of instantaneous frequency errors greater than a second frequency threshold is less than a second threshold number defined for the HST scenario.

7. The wireless communication device according to claim 6, wherein: The interface is configured to: When the wireless communication device is no longer in the HST scenario, prevent listening to the TRS during CDRx.

8. A wireless communication device, comprising: A processing system configured to: Identify whether the wireless communication device is in a High-Speed Train (HST) scenario; And Generate a frequency error through one or more Frequency Tracking Loops (FTLs); and An interface configured to: When the wireless communication device is in the HST scenario, obtain a Tracking Reference Signal (TRS) during Connected Mode Discontinuous Reception (CDRx), wherein generating the frequency error through the one or more FTLs includes: using the TRS when the wireless communication device is in the HST scenario; Obtain a first Synchronization Signal Block (SSB) at a first time; and Obtain a first TRS instance associated with the first time; and The processing system is further configured to: Generate a first SSB frequency error using the first SSB through the one or more FTLs; Generate a first TRS frequency error using the first TRS instance through the one or more FTLs; and Generate a frequency error difference between the first SSB frequency error and the first TRS frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes: using the frequency error difference.

9. The wireless communication device according to claim 8, wherein, Identifying whether the wireless communication device is in the HST scenario includes: identifying whether the frequency error difference is greater than a frequency threshold.

10. The wireless communication device according to claim 9, wherein: The interface is configured to: Obtain a plurality of SSBs in a first time period, wherein the plurality of SSBs includes the first SSB, and the first time period includes the first time; and Obtain a plurality of TRS instances in the first time period, wherein the plurality of TRS instances includes the first TRS instance, and each TRS instance in the plurality of TRS instances is associated with an SSB in the plurality of SSBs; and the processing system is configured to: Generate an SSB frequency error for each SSB in the plurality of SSBs through the one or more FTLs; Generate a TRS frequency error for each TRS instance in the plurality of TRS instances through the one or more FTLs; and For each pair of associated SSB and TRS instance, generate a frequency error difference between the SSB frequency error generated for the SSB and the TRS frequency error generated for the TRS instance, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the number of frequency error differences greater than the frequency threshold is greater than a threshold number defined for the HST scenario.

11. The wireless communication device according to claim 10, wherein: The interface is configured to: When the wireless communication device is in the HST scenario, obtain a second plurality of SSBs in a second time period; and Obtain a second plurality of TRS instances during the second time period, where each TRS instance in the second plurality of TRS instances is associated with an SSB in the second plurality of SSBs; and The processing system is configured to: Generate an SSB frequency error for each SSB in the second plurality of SSBs through the one or more FTLs; Generate a TRS frequency error for each TRS instance in the second plurality of TRS instances through the one or more FTLs; and For each pair of associated SSB and TRS instance from the second plurality of SSBs and the second plurality of TRS instances, generate a frequency error difference between the SSB frequency error generated for the SSB and the TRS frequency error generated for the TRS instance; and Identify whether the wireless communication device is no longer in the HST scenario, including identifying whether the number of frequency error differences greater than a second frequency threshold among the frequency error differences generated for the second plurality of SSBs and the second plurality of TRS instances is less than a second threshold number defined for the HST scenario.

12. The wireless communication device according to claim 11, wherein: The interface is configured to: Prevent listening to the TRS during CDRx when the wireless communication device is no longer in the HST scenario.

13. The wireless communication device according to claim 8, wherein: The interface is configured to: Obtain a second SSB at a second time; and Obtain a second TRS instance associated with the second time; and The processing system is configured to: Generate a second SSB frequency error using the second SSB through the one or more FTLs; Generate a second TRS frequency error using the second TRS instance through the one or more FTLs; And Generate a second frequency error difference between the second SSB frequency error and the second TRS frequency error, where identifying whether the wireless communication device is in the HST scenario includes: using the frequency error difference and the second frequency error difference to identify whether the frequency error difference is increasing over time.

14. A method performed by a device in a wireless communication device, including: Identify whether the wireless communication device is in a high-speed train (HST) scenario; When the wireless communication device is in the HST scenario, receive a tracking reference signal (TRS) during connected mode discontinuous reception (CDRx); When the wireless communication device is in the HST scenario, generate a frequency error using the TRS through one or more frequency tracking loops (FTLs); Receive a first instance of the TRS; Receive a second instance of the TRS; Generate a first frequency error using the first instance through the one or more FTLs; Generate a second frequency error using the second instance through the one or more FTLs; And The first frequency error and the second frequency error are used to generate an instantaneous frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the instantaneous frequency error is greater than a frequency threshold.

15. The method according to claim 14, further comprising: Receiving a synchronization signal block (SSB) during CDRx; And When the wireless communication device is not in the HST scenario, using the SSB to generate the frequency error through the one or more FTLs.

16. The method according to claim 15 further comprises: When the wireless communication device is not in the HST scenario, prevent listening to the TRS during CDRx.

17. The method according to claim 14, wherein, The instantaneous frequency error is the difference between the first frequency error and the second frequency error.

18. The method according to claim 14, further comprising: Receiving a plurality of TRS instances in a first time period, wherein the plurality of TRS instances include the first instance and the second instance; and Using the plurality of TRS instances to generate a plurality of instantaneous frequency errors, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the number of the plurality of instantaneous frequency errors greater than the frequency threshold is greater than a threshold number defined for the HST scenario.

19. The method according to claim 18, further comprising: When the wireless communication device is in the HST scenario, receiving a second plurality of TRS instances in a second time period; Using the second plurality of TRS instances to generate a second plurality of instantaneous frequency errors; And Identifying whether the wireless communication device is no longer in the HST scenario includes: identifying whether the number of the second plurality of instantaneous frequency errors greater than a second frequency threshold is less than a second threshold number defined for the HST scenario.

20. The method according to claim 19 further comprises: When the wireless communication device is no longer in the HST scenario, prevent listening to the TRS during CDRx.

21. A method performed by a device in a wireless communication device, comprising: Receiving a first SSB at a first time; Receiving a first TRS instance associated with the first time; Identifying whether the wireless communication device is in a high-speed train (HST) scenario; Generating a frequency error through one or more frequency tracking loops (FTL); When the wireless communication device is in the HST scenario, obtaining a tracking reference signal (TRS) during connected mode discontinuous reception (CDRx), wherein generating the frequency error through the one or more FTLs includes: using the TRS when the wireless communication device is in the HST scenario; Generating a first SSB frequency error through the one or more FTLs using the first SSB; Generating a first TRS frequency error through the one or more FTLs using the first TRS instance; and Generating a frequency error difference between the first SSB frequency error and the first TRS frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes: using the frequency error difference.

22. The method according to claim 21, wherein Identifying whether the wireless communication device is in the HST scenario includes: identifying whether the frequency error difference is greater than a frequency threshold.

23. The method according to claim 22, further comprising: Receiving a plurality of SSBs in a first time period, wherein the plurality of SSBs includes the first SSB, and the first time period includes the first time; Receiving a plurality of TRS instances in the first time period, wherein the plurality of TRS instances includes the first TRS instance, and each TRS instance in the plurality of TRS instances is associated with an SSB in the plurality of SSBs; and Generating an SSB frequency error for each SSB in the plurality of SSBs by means of the one or more FTLs; Generating a TRS frequency error for each TRS instance in the plurality of TRS instances by means of the one or more FTLs; and Generating a frequency error difference between the SSB frequency error generated for the SSB and the TRS frequency error generated for the TRS instance for each pair of associated SSB and TRS instance, wherein identifying whether the wireless communication device is in the HST scenario includes: identifying whether the number of frequency error differences greater than the frequency threshold is greater than a threshold number defined for the HST scenario.

24. The method according to claim 23, further comprising: Receiving a second plurality of SSBs in a second time period when the wireless communication device is in the HST scenario; Receiving a second plurality of TRS instances in the second time period, wherein each TRS instance in the second plurality of TRS instances is associated with an SSB in the second plurality of SSBs; and Generating an SSB frequency error for each SSB in the second plurality of SSBs by means of the one or more FTLs; Generating a TRS frequency error for each TRS instance in the second plurality of TRS instances by means of the one or more FTLs; Generating a frequency error difference between the SSB frequency error generated for the SSB and the TRS frequency error generated for the TRS instance for each pair of associated SSB and TRS instance from the second plurality of SSBs and the second plurality of TRS instances; and Identifying whether the wireless communication device is no longer in the HST scenario, including identifying whether the number of those greater than a second frequency threshold among the frequency error differences generated for the second plurality of SSBs and the second plurality of TRS instances is less than a second threshold number defined for the HST scenario.

25. The method according to claim 24 further comprises: When the wireless communication device is no longer in the HST scenario, preventing listening to the TRS during CDRx.

26. The method according to claim 21, further comprising: Receiving a second SSB at a second time; And Receiving a second TRS instance associated with the second time; And Generating a second SSB frequency error using the second SSB by means of the one or more FTLs; Generate a second TRS frequency error using the second TRS instance via the one or more FTLs; and Generate a second frequency error difference between the second SSB frequency error and the second TRS frequency error, wherein identifying whether the wireless communication device is in the HST scenario includes: using the frequency error difference and the second frequency error difference to identify whether the frequency error difference is increasing over time.

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