Systems, methods, and devices for secondary cell activation with ue-specific reference signals

Abstract

The techniques described herein can better ensure efficient fine time tracking during a second cell (SCell) activation procedure by using a user equipment (UE)-specific tracking reference signal (TRS). A primary cell (PCell) can provide a UE with a TRS configuration including a UE-specific reference signal (RS) with periodicity or aperiodicity. In response to receiving a SCell activation command from the PCell, the UE can perform cell activation with fine time tracking according to the UE-specific RS. Because a latency time of the UE-specific RS can be less than a latency time of a system synchronization block (SSB) from the SCell, use of the UE-specific RS can speed up the cell activation procedure.

Description

[0001] Reference to Related Applications

[0002] This application is the national stage entry of international patent application number PCT / CN2021 / 071807, filed January 14, 2021, entitled “SYSTEMS, METHODS AND DEVICES, FOR SECONDARY CELL ACTIVATION WITH UE-SPECIFIC REFERENCE SIGNAL,” the contents of which are incorporated herein in their entirety. TECHNICAL FIELD

[0003] The present disclosure relates to wireless communication networks, including techniques for secondary cell activation in a wireless communication network. Other aspects and techniques are also described. BACKGROUND

[0004] As the number of mobile devices within wireless networks and the demand for mobile data traffic continues to grow, changes to system requirements and architecture are made to better address current and expected demands. One aspect of such networks can include carrier aggregation (CA) and radio resource management (RRM). For example, a base station of a primary cell can cause a user equipment (UE) to activate communication with a base station of a secondary cell, resulting in a CA scenario for the UE involving the primary cell and the secondary cell. BRIEF DESCRIPTION OF DRAWINGS

[0005] The present disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings. Like reference numerals can designate like structural and functional elements. The drawings and corresponding description are provided as non-limiting examples of aspects, implementations, etc. of the present disclosure, and the mention of “an” or “one” aspect, implementation, etc. can not necessarily be a reference to the same aspect, implementation, etc., and can instead be a reference to at least one, one or more, etc. aspect, implementation, etc.

[0006] Figure 1 is an illustration of an example network in accordance with one or more implementations described herein.

[0007] Figure 2 is a timeline diagram of an example of secondary cell activation using user equipment (UE) specific reference signals (RSs).

[0008] Figure 3 is a flow diagram of an example process for activating a secondary cell using UE specific RSs.

[0009] Figure 4 is a sequence diagram of an example process for activating a secondary cell using UE specific RSs.

[0010] Figure 5FIG. 1 is a diagram of an example of a device according to one or more implementations described herein.

[0011] Figure 6 FIG. 1 is a diagram of an example of a device according to one or more implementations described herein. DETAILED DESCRIPTION

[0012] The following detailed description relates to the drawings. The same reference numbers in different drawings can identify the same or similar elements, features, operations, or the like. Additionally, the disclosure is not limited to the described examples because other implementations can utilize the described examples and structural or logical changes can be made without departing from the scope of the disclosure.

[0013] A mobile communication network can include one or more types and / or one or more generations of wireless communication networks, such as a 4th Generation (4G) network, a 5th Generation (5G) or New Radio (NR) network, and the like. Such networks can include user equipment (UE) and base stations. One aspect of a mobile communication network includes radio resource management (RMM), which can include configuration, assignment, allocation, management, and the like of wireless resources (e.g., channels, bandwidth, carriers, and the like) within the network. For example, carrier aggregation (CA) can include scenarios in which multiple carriers are allocated to a UE. In some scenarios, CA can involve carriers aggregated from different base stations.

[0014] For example, for purposes of RRM, CA, and the like with respect to a UE, the UE can be connected to a first carrier on a first base station operating as a primary cell (PCell). The primary cell can perform a radio resource control (RRC) connection reconfiguration procedure that includes sending UE connection configuration information and an activation command for a second carrier of the first base station or a third carrier on a second base station that can operate as a secondary cell (SCell). The UE can respond to the configuration information and the command by searching for and connecting to the SCell, resulting in a CA scenario involving the PCell, the SCell, and the UE.

[0015] To connect to the SCell, the UE can perform timing synchronization, which can include coarse timing synchronization and fine timing synchronization (also referred to herein as fine time tracking). The coarse timing synchronization can generate an initial estimate of a starting index or symbol for communication with the SCell, and the fine time tracking can improve the initial estimate toward an ideal or more accurate starting point for communication with the SCell. Because the timing synchronization can be performed before the SCell activation is complete, a duration involved with the SCell activation can depend at least in part on a time involved with the fine time tracking. Moreover, because the timing synchronization can depend on a reference signal (RS) from a signal synchronization block (SSB) of the SCell, the SCell activation time (or activation delay) can depend on an SSB periodicity of the SCell.

[0016] For example, the SCell activation delay can include a duration between an end of a first full SSB burst indicated by a SSB-based RRM measurement timing configuration (SMTC) after slot n + hybrid automatic repeat request time (Time_HARQ) + 3 ms, where n is a time when the UE receives a medium access control (MAC) command including a SCell activation command, Time_HARQ is a duration associated with a HARQ message corresponding to the MAC command, and NR slot length is a specified slot length for performing fine time tracking during TRS. In another example, the SCell activation delay can be further extended by a RS time (Trs) provided by a measurement object or a default duration indicated by the SMTC. In yet another example, the SCell activation delay can include a duration between the UE completing processing of a last activation command for a physical downlink control channel (PDCCH) transmission configuration indicator (TCI), a physical downlink shared channel (PDSCH) TCI (when applicable), and timing of a first full available SSB corresponding to the TCI state. Thus, the activation time for the SCell can be long because the RS for synchronization can depend on the SSB periodicity of the SCell (e.g., 160 milliseconds) and other durations that can sometimes be involved. These durations, in turn, delay the SCell activation and CA.

[0017] The techniques described herein can improve the activation efficiency of a SCell by implementing a UE-specific RS for fine time tracking instead of a cell-specific RS (e.g., via SSB). The UE-specific RS can be configured to have a short periodicity (e.g., a periodicity that is shorter than the SSB periodicity of the SCell) or be aperiodic that occurs well within the SSB periodicity of the SCell. In some implementations, the UE-specific RS for fine time tracking during the SCell activation procedure can be a tracking reference signal (TRS). The network (e.g., a PCell) can configure the TRS via an RRC message containing a SCell addition (e.g., via a RRC connection configuration procedure, a RRC connection reconfiguration procedure, etc.).

[0018] Later, the PCell can send a medium access control (MAC) control element including a SCell activation command to the UE. In response, the UE can perform a cell search procedure and automatic gain control (AGC) adjustment for the SCell. Additionally, the UE can use the TRS to quickly perform fine timing tracking and / or AGC (e.g., right before receiving and processing the next SSB from the SCell) and continue to quickly complete the SCell activation procedure.

[0019] In some implementations, the TRS of the SCell can be periodic or aperiodic. When the TRS is periodic, the delay of the fine time tracking and / or ACG can be based on the TRS periodicity. When the TRS is aperiodic, the delay of the fine time tracking and / or ACG can depend on network scheduling (e.g., when the TRS transmission is triggered). In some implementations, the aperiodic TRS can be transmitted shortly after the PCell transmits an SCell activation command to the UE. In some implementations, the aperiodic TRS can be triggered by the network (e.g., the PCell) via a downlink control information (DCI) and / or a MAC command, which can be communicated after sending the SCell activation command to the UE. When the TCI is configured by the network, the TRS can be transmitted after the UE successfully decodes the TCI command from the PCell. When the TCI is not configured, the TRS can be transmitted after the UE receives the MAC CE with the SCell activation command. For example, the TRS can be transmitted at slot n + (Time HARQ + 3ms) / (NR slot length), where n is the time the UE receives the MAC CE, Time HARQ is the time associated with the HARQ message of the MAC CE, and the new radio (NR) slot length is the specified slot length for performing fine time tracking during the TRS.

[0020] In some implementations, Time FineTiming can include a duration between the UE completing processing of the last activation command of PDCCH TCI, PDSCH TCI (when applicable) and one of: 1) the first fully available SSB corresponding to the TCI state when TRS is not configured, or the first fully available TRS occasion with the same TCI state when TRS is configured. Alternatively, when TRS is configured, Time FineTiming can be further divided into two cases: periodic and aperiodic. When periodic TRS is configured, Time FineTiming can be the periodicity of the TRS. When aperiodic TRS is configured, Time FineTiming can be a duration between the UE completing processing of the last activation command of PDCCH TCI, PDSCH TCI (when applicable) and the timing of the first fully available TRS occasion with the same TCI state when TRS is configured.

[0021] In some implementations, with respect to RRM conditions for fine time tracking during SCell activation, Time_FirstSSB can be the duration from the end of the first full SSB burst indicated by SMTC after slot n + Time_HARQ + 3 ms, when SMTC is configured on the target SCell, or when TRS is configured, Time_FirstSSB can be the duration to the end of the first full available TRS occasion (if configured, with the same TCI state) after n + Time_HARQ + 3 ms. In either scenario, Time_FirstSSB_MAX can be the time to the end of the first full available TRS occasion (if configured, with the same TCI state) after slot n + Time_HARQ + 3 ms.

[0022] Alternatively, when TRS is configured, the RRM conditions can be further divided into two cases: periodic and aperiodic. When periodic TRS is configured, Time_FirstSSB can be equal to Time_TRS, and Time_FirstSSB_MAX can be equal to Time_PRS, where Time_PRS is the periodicity of PRS. When aperiodic TRS is configured, Time_FirstSSB and Time_FirstSSB_MAX are the durations between the UE completing processing of the SCell activation command and the timing of the first full available TRS occasion (if configured, with the same TCI state).

[0023] Figure 1 is an example network 100 according to one or more implementations described herein. The example network 100 can include UEs 110-1, 110-2, and so on (collectively referred to as “UEs 110,” and individually as “UE 110”), a radio access network (RAN) 120, a core network (CN) 130, an application server 140, an external network 150, and satellites 160-1, 160-2, and so on (collectively referred to as “satellites 160,” and individually as “satellite 160”). As illustrated, the network 60 can include a non-terrestrial network (NTN) that includes one or more satellites 160 (e.g., of a global navigation satellite system (GNSS)) in communication with UEs 110 and RAN 120.

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

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

[0026] The UE 110 can communicate and establish connections (e.g., communicatively coupled) with the RAN 120, which can involve one or more wireless channels 114-1 and 114-2, each of which can comprise a physical layer / interface for communication. In some implementations, the UE can be configured with dual connectivity (DC) as multi-radio access technology (multi-RAT) or multi-radio dual connectivity (MR-DC), where a multiple receive and transmit (Rx / Tx) capable UE can use resources provided by different network nodes (e.g., 122-1 and 122-2), which can be connected through a non-ideal backhaul (e.g., where one network node provides NR access and the other network node provides E-UTRA for LTE or NR access for 5G). In such scenarios, one network node can act as a master node (MN) and the other node can act as a secondary node (SN). The MN and SN can be connected via a network interface, and at least the MN can be connected to the CN 130. Additionally, at least one of the MN or SN can operate with shared spectrum channel access, and the functionality designated for the UE 110 can be for an integrated access and backhaul mobile terminal (IAB-MT). Similar to the UE 61, the IAB-MT can access the network using one network node or using two different nodes with an enhanced dual connectivity (EN-DC) architecture, a new radio dual connectivity (NR-DC) architecture, etc.

[0027] As shown, the UE 110 can also or alternatively connect to an access point (AP) 116 via an interface 118, which can include an over-the-air interface that enables the UE 110 to communicatively couple with the AP 116. The AP 116 can comprise a wireless local area network (WLAN), a WLAN node, a WLAN termination point, etc. The connection 1207 can comprise a local wireless connection, such as a connection consistent with any IEEE 702.11 protocol, and the AP 116 can comprise a wireless fidelity router or other AP. While the connection 1207 is shown as a wireless connection, the connection 1207 can be a wired connection. The connection 1207 can be a direct connection between the UE 110 and the AP 116 or can be an indirect connection between the UE 110 and the AP 116, such as a connection that passes through one or more other devices. Figure 1The network is not explicitly depicted but the AP 116 can be connected to another network (e.g., the Internet) without connection to the RAN 120 or the CN 130. In some scenarios, the UE 110, the RAN 120, and the AP 116 can be configured to utilize LTE-WLAN aggregation (LWA) technology or LTE WLAN radio level technology integrated with IPsec tunnel (LWIP). LWA can involve the RAN 120 configuring the UE 110 in an RRC CONNECTED state to utilize radio resources of LTE and WLAN. LWIP can involve the UE 110 using WLAN radio resources (e.g., the connectivity interface 118) via IPsec protocol tunneling to authenticate and encrypt packets (e.g., Internet Protocol (IP) packets) communicated over the connectivity interface 118. IPsec tunneling can include encapsulating the entire original IP packet and adding a new packet header, thereby protecting the original header of the IP packet.

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

[0029] Some or all of the RAN nodes 122 can be implemented as one or more software entities running on a server computer as part of a virtual network, which can be referred to as a centralized RAN (CRAN) and / or a virtual baseband unit pool (vBBUP). In these implementations, the CRAN or vBBUP can enable a splitting of RAN functions, such as a packet data convergence protocol (PDCP) split, where radio resource control (RRC) and PDCP layers can be operated by the CRAN / vBBUP and other layer 2 (L2) protocol entities can be operated by individual RAN nodes 122; a medium access control (MAC) / physical (PHY) split, where RRC, PDCP, radio link control (RLC), and MAC layers can be operated by the CRAN / vBBUP and a PHY layer can be operated by individual RAN nodes 122; or a“lower PHY” split, where RRC, PDCP, RLC, MAC layers, and an upper part of the PHY layer can be operated by the CRAN / vBBUP and a lower part of the PHY layer can be operated by individual RAN nodes 122. This virtualized framework can allow for offloading of processing needs of the RAN nodes 122.

[0030] In some implementations, individual RAN nodes 122 can represent individual gNB distributed units (DUs) connected to a gNB central unit (CU) via individual Fl interfaces. In such implementations, the gNB-DUs can include one or more remote radio heads or radio frequency (RF) front end modules (RFEMs), and the gNB-CU can be operated by a server (not shown) located in the RAN 120 or by a pool of servers, for example, a group of servers configured to share resources, in a similar manner as the CRAN / vBBUP. Additionally or alternatively, one or more of the RAN nodes 122 can be next generation e Bs (i.e., gNBs), can provide evolved universal terrestrial radio access (E-UTRA) user plane and control plane protocol terminations towards the UEs 110, and can be connected to a 5G core network (5GC) 130 via an NG interface.

[0031] Any of the RAN nodes 122 can terminate the air interface protocol and can be the first point of contact for a UE 110. In some implementations, any of the RAN nodes 122 can fulfill various logical functions for the RAN 120 including, but not limited to, RNC functions such as radio

[0032] In some implementations, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes 122 to the UEs 110, and uplink transmissions can utilize a similar grid. The grid can be a time-frequency grid, called a resource grid or time-frequency resource grid, which is

[0033] Further, RAN nodes 122 can be configured to wirelessly communicate with UEs 110 and / or with each other over a licensed medium (also referred to as a“licensed spectrum” and / or a“licensed band”), an unlicensed shared medium (also referred to as an“unlicensed spectrum” and / or an“unlicensed band”), or a combination thereof. The licensed spectrum can include channels that are licensed for use, e.g., by a particular group of network operators, for particular wireless services, or the like. For example, the licensed spectrum can correspond to channels that are licensed for use by particular network operators for wireless telecommunications network services. The unlicensed shared spectrum can include one or more frequency bands that are unlicensed for specific wireless services, and thus available for use by any suitable wireless communication network(s) or device(s) that comply with the requirements for use of the frequency bands. For example, the unlicensed shared spectrum can include the 5 GHz band, which is unlicensed for wireless telecommunications network services in many countries. The unlicensed shared spectrum can also include the 2.4 GHz and / or 5 GHz bands, which are unlicensed for Wi-Fi services. The unlicensed shared spectrum can also include the 600 GHz band, which is unlicensed for use by wireless communication networks and devices. The unlicensed shared spectrum can also include the V-band (57-71 GHz), W-band (71-76 GHz), and D-band (81-86 GHz), which are unlicensed for use by wireless communication networks and devices. Whether a particular band corresponds to a licensed or unlicensed medium can depend on one or more factors, such as frequency allocation determined by public sector organizations (e.g., government bodies, regulatory authorities, etc.), frequency allocation determined by private sector organizations involved in developing wireless communication standards and protocols, and the like.

[0034] To operate in the unlicensed spectrum, UEs 110 and RAN nodes 122 can operate using License Assisted Access (LAA), eLAA, and / or feLAA mechanisms. In these implementations, UEs 110 and RAN nodes 122 can perform one or more known clear channel assessment or carrier sense operations to determine whether one or more channels in the unlicensed spectrum are unavailable or otherwise occupied before transmitting in the unlicensed spectrum. The medium / carrier sensing operations can be performed according to Listen-Before-Talk (LBT) protocols.

[0035] The LAA mechanisms can be built on top of the Carrier Aggregation (CA) techniques of the LTE-Advanced system. In CA, each aggregated carrier is referred to as a component carrier (CC). In some cases, individual CCs can have a different bandwidth than other CCs. In a time division duplex (TDD) system, the number of CCs and the bandwidth of each CC can be the same for DL and UL. CA also involves individual serving cells to provide individual CCs. The coverage of the serving cells can differ, for example, because CCs on different frequency bands will experience different pathloss. A primary serving cell or a PCell can provide a primary component carrier (PCC) for both UL and DL, and can handle radio resource control (RRC) and non-access stratum (NAS) related activities. Other serving cells are referred to as SCells, and each SCell can provide a single secondary component carrier (SCC) for both UL and DL. SCCs can be added and removed as required, while changing the PCC can require the UE 110 to undergo a handover. In LAA, eLAA, and feLAA, some or all of the SCells can operate in unlicensed spectrum (referred to as “LAA SCells”), and are assisted by a PCell operating in licensed spectrum. When a UE is configured with more than one LAA SCell, the UE can receive a UL grant on a configured LAA SCell indicating different PUSCH start positions within a same subframe.

[0036] The PDSCH can carry user data and higher layer signaling to the UEs 110. A physical downlink control channel (PDCCH) can carry information about the transport format and resource allocations for the PDSCH channel, etc. It can also inform the UEs 110 about the transport format, resource allocation, and Hybrid Automatic Repeat Request (HARQ) information of the uplink shared channel. Generally, downlink scheduling (e.g., assigning control and shared channel resource blocks to the UEs 110-2 within a cell) can be performed at any of the RAN nodes 122 based on channel quality information fed back from any of the UEs 110. The downlink resource assignment information can be sent to a UE 110 on the PDCCH used for (e.g., assigned to) that UE 110.

[0037] A PDCCH uses control channel elements (CCEs) to convey control information, where a number of CCEs (for example, 6, and so on) can be composed of resource element groups (REGs), where a REG is defined as a PRB in an OFDM symbol. Prior to being mapped to resource elements, the PDCCH complex-valued symbols can first be organized into quadruplets, which can then be permuted using a sub-block interleaver to facilitate rate matching. One or more of these CCEs can be used to transmit each PDCCH, where each CCE can correspond to nine sets of four physical resource elements known as REGs. Four Quadrature Phase Shift Keying (QPSK) symbols can be mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of the DCI and the channel condition. There can be four or more different PDCCH formats defined in LTE with different numbers of CCEs (for example, aggregation level, L=1, 2, 4, 8, or 110) used for transmission of the PDCCH.

[0038] Some implementations can use concepts for resource allocation for control channel information that are an extension of those described above. For example, some implementations can utilize an extended (E)-PDCCH that uses PDSCH resources for control information transmission. An EPDCCH can be transmitted using one or more ECCEs. Similar to above, each ECCE can correspond to nine sets of four physical resource elements known as EREGs. An ECCE can have other numbers of EREGs in some cases.

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

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

[0041] As illustrated, the CN 130, application server (AS) 140, and external networks 150 can be connected to each other via interfaces 134, 136, and 138, which can include IP network interfaces. Application server 140 can include one or more server devices or network elements (e.g., virtual network functions (VNFs)) that provide applications using IP bearer resources through the CN 130 (e.g., General Mobile Communication System Packet Service (UMTS PS) domain, LTE PS data services, etc.). The application server 140 can also or alternatively be configured to support one or more communication services for UEs 110 (e.g., Voice-over-Internet Protocol (VoIP) sessions, Push-to-Talk (PTT) sessions, group communication sessions, social networking services, etc.) via the CN 130. Similarly, the external networks 150 can include one or more of various networks, including the Internet, thereby providing mobile communication networks and UEs 110 with access to various additional services, information, connectivity, and other features of the networks.

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

[0043] Figure 2 is a timeline diagram of an example 200 of a secondary cell activation using a UE-specific RS. As shown, example 200 includes a timeline 210 and corresponding SSBs 220-1, 220-2,... SSB 220-3 (collectively, “SSBs 220”). UE 110-1 can receive and process an activation command at 230 after SSB 220-1. In implementations in which the network has not configured a TRS (e.g., the PCell has not provided the UE 110-1 with a TRS configuration for the SCell), UE 110-1 can perform fine time tracking based on a first complete SSB 220-2 of the corresponding TCI state received by UE 110-1.

[0044] In contrast, in implementations where the network has configured TRS (e.g., the PCell has provided the UE 110-1 with a TRS configuration for an SCell), the UE 110-1 can perform fine time tracking based on the TRS 240 from the SCell. As described herein, the TRS configuration can be periodic or aperiodic. In the example 200, if the TRS configuration is periodic, DELTA_T 250 (e.g., Time_FineTiming) is the periodicity of the TRS configuration. Conversely, if the TRS configuration is aperiodic, DELTA_T 250 (e.g., Time_FineTiming) can be the duration between the UE completing processing of the last activation command for PDCCH TCI, PDSCH TCI (when applicable), and the timing of the first fully available TRS 240. Thus, the techniques described herein enable fine time tracking based on SSB, periodic TRS, or aperiodic TRS.

[0045] Figure 3 is a flow diagram of an example procedure 300 for activating a secondary cell using a UE-specific RS. The procedure 300 can be implemented by a UE 110. In some implementations, some or all of the procedure 300 can be performed by one or more other systems or devices, including one or more of the devices of Figure 1 FIG. 13. Additionally, the procedure 300 can include more, fewer, a different Figure 3 ordering and / or arrangement of operations than those shown in FIG. 13. Moreover, as discussed with respect to the example procedure 300 and corresponding description of FIG. 13, the scope of the techniques described herein includes corresponding procedures that can be performed by a corresponding base station (e.g., a RAN node 112), a satellite, and / or other network device, as described with respect to Figure 3 FIG. 14. Figure 1

[0046] ​As illustrated, process 300 can include receiving a TRS configuration for a SCell from a PCell during an RRC configuration procedure (block 310). For example, a base station operating as a PCell for UE 110 can provide UE 110 with a TRS configuration for another base station that is intended to operate as a SCell for UE 110. As described herein, the TRS configuration can include a TRS during which UE 110 can synchronize (e.g., perform fine time tracking) with the SCell based on a UE-specific RS. In some implementations, UE 110 can also receive other types of configuration information for the SCell, such as SMTC information, TCI information, and the like. In some implementations, UE 110 can receive another MAC command or DCI message indicating the TRS configuration (e.g., a TRS transmission). In some implementations, when no TRS configuration is provided, UE 110 can receive SMTC and / or TCI for the SCell and perform fine time tracking based on an SSB for the SCell.

[0047] Process 300 can also include receiving a SCell activation message and performing a cell search and AGC for the SCell (block 320). For example, UE 110 can receive a MAC CE from the PCell including an activation command for the SCell. In some implementations, the activation command can correspond to a carrier on the SCell. The carrier on the SCell can be part of a CA configuration for UE 110 (which can include one or more carriers for the PCell). In response to the activation command, UE 110 can perform a cell search and AGC for the SCell.

[0048] Process 300 can include determining whether periodicity or aperiodicity applies to a TRS for the SCell based on the TRS configuration (block 330). For example, UE 110 can determine whether the SCell implements periodicity or aperiodicity for the TRS based on the TRS configuration received from the PCell. UE 110 can also or alternatively determine a transmission time for the TRS based on the TRS configuration.

[0049] Process 300 can include performing fine time tracking and / or AGC according to the TRS periodicity when periodicity applies to the TRS (block 340). For example, UE 110 can perform fine time tracking and / or AGC based on the periodicity of the TRS. As described herein, when UE 110 performs fine time tracking and / or AGC based on the periodicity of the TRS, Time_FineTiming can be equal to the periodicity of the PRS.

[0050] The process 300 can include determining whether a TCI command is configured for the SCell, when aperiodic applies (block 350). For example, when aperiodic applies to TRS, the UE 110 can determine whether a TCI command has been configured for the SCell. In some implementations, the TCI state can be provided to the UE 110 as part of the RRC configuration process, and the PCell can send the TCI command to the UE 110 in a MAC CE, which can be the same or a different MAC CE as the SCell activation command.

[0051] The process 300 can also include performing fine time tracking and / or AGC after the TCI command is decoded, when TRS aperiodic and TCI configuration apply to SCell activation (block 360). For example, when the SCell uses TRS aperiodic, the UE 110 can determine whether a TCI command has been received for SCell activation, and if so, perform fine time tracking during the TRS after the TCI command is decoded by the UE 110.

[0052] The process 300 can include performing fine time tracking and / or AGC during the TRS after N + (T HARQ + 3ms) / (NR slot length), when TRS aperiodic applies but no TCI command is configured (block 370). For example, when the UE 110 determines that TRS aperiodic applies but no TCI command is configured for SCell activation, the UE 110 can perform fine time tracking during the TRS that occurs after N + (T HARQ + 3ms) / (NR slot length).

[0053] Figure 4 is a sequence diagram of an example process 400 to activate a secondary cell using a UE-specific RS. As shown, the example process 400 can involve the UE 110, a base station 122-1 (operating as a PCell connected to the UE 110), and a base station 122-2 (operating as an SCell for the UE 110). In some implementations, the example process 400 can include one or more additional, alternative, fewer, or different arrangements of operations and / or devices than those shown in Figure 4 Figure 4

[0054] ​​As illustrated, base station 122-1 and UE 110 can engage in an RRC procedure, such as an RRC connection reconfiguration procedure (at 402). During this procedure, base station 122-1 can provide UE 110 with a TRS configuration for a SCell (e.g., base station 122-2). At some point, base station 122-1 can transmit a MAC CE to UE 110 that can include a command to activate base station 122-2 as a SCell for UE 110 (at 404). This activation command can include the TRS configuration for base station 122-2. In some implementations, the MAC CE can also include a TCI command for base station 122-2 or another type of TCI. In some implementations, the TCI command can be transmitted in a different MAC CE. In still other implementations, no TCI command can be transmitted.

[0055] In response to the activation command, UE 110 can initiate performing a cell search and AGC adjustment with respect to base station 122-2 (at 406). Additionally, UE 110 can determine the TRS configuration for base station 122-2 (at 408). The TRS configuration can indicate a UE-specific RS that can be used by UE 110 for synchronization with respect to base station 122-2 (e.g., performing fine time tracking). In some implementations, this can include UE 110 determining whether the TRS for base station 122-2 is periodic or aperiodic. In some implementations, UE 110 can also determine the TCI configuration for base station 122-2, such as in scenarios where a TCI command is transmitted. In some implementations, base station 122-1 can communicate a TRS trigger to UE 110, which can cause or prompt UE 110 to perform fine time tracking with respect to the TRS (e.g., start performing fine time tracking during the TRS) (at 410). In some implementations, the TRS trigger can be part of a MAC command. In some implementations, the TRS can be part of a DCI. In some implementations, the PCell can communicate the TRS trigger at another time, such as before or concurrently with UE 110 determining the TRS configuration.

[0056] As illustrated, UE 110 can perform fine time tracking based on the TRS configuration for base station 122-2. As described above, this can depend in part on whether the TRS is periodic or aperiodic. Also as described herein, in some implementations, fine time tracking can also be based on the TCI configuration for base station 122-2 and when UE 110 processes the TCI command. UE 110 can continue by completing the SCell activation with respect to base station 122-2, which can later result in a CA scenario involving UE 110, base station 122-1, and base station 122-2.

[0057] Figure 5FIG. 1 is a diagram of an example of a device in accordance with one or more implementations described herein. In some implementations, the device 500 can include application circuitry 502, baseband circuitry 504, Radio-Frequency (“RF”) circuitry 506, front-end module (“FEM”) circuitry 508, one or more antennas 510, and power management circuitry (“PMC”) 512 coupled together as shown in the figure, or as known by those in the art. These circuitries can be included in a UE or a RAN node. In some implementations, the device 500 can include less circuitry (e.g., a RAN node does not utilize application circuitry 502, but rather includes a processor / controller to process IP data received from a CN, such as the 5GC 130 or an evolved packet core (EPC)). In some implementations, the device 500 can include additional elements such as memory / storage, displays, cameras, sensors (including one or more temperature sensors, such as a single temperature sensor, multiple temperature sensors at different locations in the device 500, etc.), or input / output (I / O) interfaces. In other implementations, components described can be included in multiple devices (e.g., the circuitries described can be individually included in multiple devices for a cloud-RAN (C-RAN) implementation).

[0058] The application circuitry 502 can include one or more application processors. For example, the application circuitry 502 can include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processors can include general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). Processors can be coupled with or can include memory / storage and can be configured to execute instructions stored in the memory / storage to enable various applications or operating systems to run on the device 500. In some implementations, the processors of application circuitry 502 can process IP data packets received from an EPC.

[0059] The baseband circuitry 504 can include circuitry such as one or more single-core or multi-core processors. The baseband circuitry 504 can include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry 506 and to generate baseband signals for a transmit signal path of the RF circuitry 506. The baseband processing circuitry 504 can interface with the application circuitry 502 for generation and processing of the baseband signals and for control of the RF circuitry 506. For example, in some implementations, the baseband circuitry 504 can include a third generation (3G) baseband processor 504A, a fourth generation (4G) baseband processor 504B, a fifth generation (5G) baseband processor 504C, or other baseband processor(s) 504D (e.g., 2nd, 6th, etc.) of other existing generations, in development, or in future development. The baseband circuitry 504 (e.g., one or more baseband processors 504A-D) can handle various radio control functions, which can include, for example, signaling and / or data transfer functions in the 3GPP network. In other implementations, some or all of the functions handled by the baseband processor(s) 504A-D can be handled by the central processing unit (CPU) 504E executing modules stored in the memory 504G. The radio control functions can include, for example, signal modulation / demodulation, encoding / decoding, radio frequency shifting, etc. In some implementations, the modulation / demodulation circuitry of the baseband circuitry 504 can include fast Fourier transform (FFT), precoding, or constellation mapping / demapping functionality. In some implementations, the encoding / decoding circuitry of the baseband circuitry 504 can include convolution, tail-biting convolution, turbo, Viterbi, or low-density parity check (LDPC) encoder / decoder functionality. The implementations of the modulation / demodulation and encoder / decoder functionality are not limited to these examples and can include other suitable functionality in other implementations.

[0060] In some implementations, the baseband circuitry 504 can include one or more audio digital signal processor(s) (DSP) 504F. The audio DSP(s) 504F can include elements for compression / decompression and echo cancellation, and can include other suitable processing elements in other embodiments. In some implementations, components of the baseband circuitry can be combined in a single chip or set of chips with other components such as, for example, in a system on a chip (SoC).

[0061] In some implementations, the baseband circuitry 504 can provide for communication compatible with one or more radio technologies. For example, in some implementations, the baseband circuitry 504 can support communication with an NG-RAN, an evolved universal terrestrial radio access network (EUTRAN), or other wireless metropolitan area networks (WMANs), a wireless local area network (WLAN), a wireless personal area network (WPAN), etc. Implementations of the baseband circuitry 504 configured to support wireless communication according to more than one radio access technology can be referred to as multi-mode baseband circuitry.

[0062] The RF circuitry 506 can enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various implementations, the RF circuitry 506 can include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 506 can include a receive signal path, which can include circuitry to down-convert and amplify the received signal and provide the baseband circuitry 504 with baseband signals. RF circuitry 506 can also include a transmit signal path, which can include circuitry to amplify and up-convert the baseband signals provided by the baseband circuitry 504 and provide the FEM circuitry 508 with RF output signals for transmission.

[0063] In some implementations, the receive signal path of the RF circuitry 506 can include mixer circuitry 506a, amplifier circuitry 506b and filter circuitry 506c. In some implementations, the transmit signal path of the RF circuitry 506 can include filter circuitry 506c and mixer circuitry 506a. RF circuitry 506 can also include synthesizer circuitry 506d for synthesizing frequencies

[0064] In some implementations, the mixer circuitry 506a of the transmit signal path can be configured to up-convert input baseband signals based on the synthesis frequency provided by the synthesizer circuitry 506d to generate RF output signals for the FEM circuitry 508. The baseband signals can be provided by the baseband circuitry 504 and can be filtered by filter circuitry 506c.

[0065] In some implementations, the mixer circuitry 506a of the receive signal path and the mixer circuitry 506a of the transmit signal path can include two or more mixers and can be arranged for quadrature downconversion and upconversion, respectively. In some implementations, the mixer circuitry 506a of the receive signal path and the mixer circuitry 506a of the transmit signal path can include two or more mixers and can be arranged for image rejection (e.g., Hartley image rejection). In some implementations, the mixer circuitry 506a of the receive signal path and the mixer circuitry 506a can be arranged for direct downconversion and direct upconversion, respectively. In some implementations, the mixer circuitry 506a of the receive signal path and the mixer circuitry 506a of the transmit signal path can be configured for superheterodye operation.

[0066] In some implementations, the output baseband signals and the input baseband signals can be analog baseband signals, although the scope of the implementations is not limited in this respect. In some alternative implementations, the output baseband signals and the input baseband signals can be digital baseband signals. In these alternative implementations, the RF circuitry 506 can include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 504 can include a digital baseband interface to communicate with the RF circuitry 506.

[0067] In some dual-mode implementations, separate radio ICs can be provided to process signals for each spectrum, although the scope of the implementations is not limited in this respect.

[0068] In some implementations, the synthesizer circuitry 506d can be a fractional-N synthesizer or a fractional N / N+1 synthesizer, although the scope of the implementations is not limited in this respect as other types of frequency synthesizers can be suitable. For example, synthesizer circuitry 506d can be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer that includes a phase-locked loop with a frequency divider.

[0069] The synthesizer circuitry 506d can be configured to synthesize an output frequency for use by the mixer circuitry 506a of the RF circuitry 506 based on a frequency input and a divider control input. In some implementations, the synthesizer circuitry 506d can be a fractional N / N+1 synthesizer.

[0070] In some implementations, the frequency input can be provided by a voltage controlled oscillator (VCO), although this is not a requirement. The divider control input can be provided by the baseband circuitry 504 or the application processor 502 in dependence on the desired output frequency. In some implementations, the divider control input (e.g., N) can be determined from a look-up table based on the channel indicated by the application processor 502.

[0071] Synthesizer circuitry 506d of the RF circuitry 506 can include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some implementations, the divider can be a dual modulus divider (DMD) and the phase accumulator can be a digital phase accumulator (DPA). In some implementations, the DMD can be configured to divide the input signal by either N or N+1 (e.g., based on a carry out) to provide a fractional division ratio. In some example implementations, the DLL can include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these implementations, the delay elements can be configured to divide the VCO period by Nd, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help assure that the total delay through the delay line is a multiple of the VCO period.

[0072] In some implementations, the synthesizer circuitry 506d can be configured to generate a carrier frequency as an output frequency, while in other implementations, the output frequency can be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some implementations, the output frequency can be a LO frequency (fLO). In some implementations, the RF circuitry 506 can include an IQ / polar converter.

[0073] FEM circuitry 508 can include a receive signal path, which can include circuitry configured to operate on RF signals received from one or more antennas 56, amplify the received signal and provide the amplified version of the received signal to the RF circuitry 506 for further processing. FEM circuitry 508 can also include a transmit signal path, which can include circuitry configured to amplify signals for transmission provided by the RF circuitry 506 for transmission by one or more of the one or more antennas 56. In various implementations, the amplification through the transmit or receive signal paths can be done only in the RF circuitry 506, only in the FEM 508, or in both the RF circuitry 506 and the FEM 508.

[0074] In some implementations, the FEM circuitry 508 can include a TX / RX switch to switch between transmit mode and receive mode operation. The FEM circuitry can include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry can include a low-noise amplifier (LNA) to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 506). The transmit signal path of the FEM circuitry 508 can include a power amplifier (PA) to amplify signals for transmission (e.g., by one or more of the antennas 56) and one or more filters to generate RF signals for subsequent transmission.

[0075] In some implementations, the PMC 512 can manage power provided to the baseband circuitry 504. In particular, the PMC 512 can control power-source selection, voltage scaling, battery-charging, or DC-to-DC conversion. The PMC 512 can typically be included on devices that are powered by batteries, such as when the device is included in a UE. The PMC 512 can increase the power conversion efficiency in providing the desired implementation size and heat dissipation characteristics.

[0076] Although Figure 5 The PMC 512 is shown to be coupled with only the baseband circuitry 504. However, in other implementations, the PMC 512 can be additionally or alternatively coupled with, and perform similar power management operations for, other components such as, but not limited to, the application circuitry 502, RF circuitry 506, or FEM 508.

[0077] In some implementations, the PMC 512 can control, or otherwise be part of, various power saving mechanisms of the device 500. For example, if the device 500 is in an RRC_Connected state, where it is still connected to a RAN node as it expects a traffic shortly, after a period of inactivity, the device 500 can enter a state known as Discontinuous Reception Mode (DRX) during which it periodically wakes up to receive data and sleeps in between. During this state, the device 500 can power down for periods between wake ups, thereby conserving power.

[0078] If there is no data traffic activity for an extended period of time, the device 500 can transition off to an RRC_Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The device 500 goes into a very low power state and it performs paging where again it periodically wakes up to receive data and sleeps between wake ups. The device 500 can not receive data in this state; in order to receive data, it can transition back to an RRC_Connected state.

[0079] An additional power-saving mode allows the device to be unavailable from the network for periods exceeding the paging interval (ranging from seconds to hours). During this time, the device is completely unconnected to the network and can be completely powered off. Any data sent during this period will incur significant latency, which is assumed to be acceptable.

[0080] The processor of application circuit 502 and the processor of baseband circuit 504 can be used to execute elements of one or more instances of the protocol stack. For example, the processor of baseband circuit 504 can be used alone or in combination to perform layer 3, layer 2, or layer 1 functions, while the processor of application circuit 502 can utilize data received from these layers (e.g., packet data) and further perform layer 4 functions (e.g., Transport Communication Protocol (TCP) and User Datagram Protocol (UDP) layers). As mentioned herein, layer 3 may include the Radio Resource Control (RRC) layer, which will be described in further detail below. As mentioned herein, layer 2 may include the Media Access Control (MAC) layer, the Radio Link Control (RLC) layer, and the Packet Data Convergence Protocol (PDCP) layer, which will be described in further detail below. As mentioned herein, layer 1 may include the physical (PHY) layer of the UE / RAN node, which will be described in further detail below.

[0081] Figure 6 This is a diagram of an exemplary interface of a baseband circuit according to one or more specific embodiments described herein. As discussed above, Figure 5 The baseband circuit 504 may include processors 504A-904E and memory 504G utilized by the processors. Each of the processors 504A-204E may include a memory interface 604A-604E for sending / receiving data to / from memory 504G.

[0082] Baseband circuit 504 may further include: one or more interfaces for communicatively coupling to other circuits / devices, such as memory interface 612 (e.g., an interface for sending / receiving data to / from a memory external to baseband circuit 504); application circuit interface 614 (e.g., for sending / receiving data to / from a memory external to baseband circuit 504); and application circuit interface 614 (e.g., for sending / receiving data to / from a memory external to baseband circuit 504). Figure 5 Application circuit 502 (interface for sending / receiving data); RF circuit interface 616 (e.g., for sending / receiving data to / from...). Figure 5 RF circuit 506 (interface for transmitting / receiving data); wireless hardware connection interface 618 (e.g., for transmitting / receiving data to / from near field communication (NFC) components, Components (e.g.) (low power consumption) Interface for sending / receiving data to / from components and other communication components; and power management interface 620 (e.g., an interface for sending / receiving power or control signals to / from PMC 512).

[0083] Examples herein can include subject matter such as a method, means for performing acts of the method, a machine-readable medium including executable instructions that, when performed by a machine (e.g., processor with memory, application-specific integrated circuit (ASIC), field programmable gate array (FPGA), etc.) cause the machine to perform acts of a method or of an apparatus or system that uses concurrent communication of multiple communication technologies according to described implementations and examples.

[0084] In embodiment 1, a user equipment (UE) device can include radio frequency (RF) circuitry configured to communicate with a wireless communication network, a memory device configured to store instructions, and one or more processors connected to the RF circuitry and the memory device and configured to execute the instructions to: receive, via the RF circuitry and from a first carrier of a first base station operating as a primary cell of the UE, a tracking reference signal (TRS) configuration indicating a UE-specific reference signal (RS) corresponding to a second carrier of the first base station or a third carrier of a second base station designated to operate as a secondary cell of the UE; receive, via the RF circuitry and from the primary cell, an activation command for the secondary cell; and in response to the activation command, perform a secondary cell activation procedure with the second base station including fine time tracking based on the UE-specific RS.

[0085] In embodiment 2, the one or more processors are configured to determine a periodicity of the UE-specific RS based on the TRS configuration and perform the fine time tracking according to the periodicity of the UE-specific RS. In embodiment 3, the one or more processors are configured to determine that the UE-specific RS is an aperiodic RS based on the TRS configuration and perform the fine time tracking based on a transmission time of the activation command. In embodiment 4, the fine time tracking is performed based on a duration associated with a hybrid automatic repeat request (HARQ) message associated with the activation command.

[0086] In embodiment 5, the one or more processors are configured to detect a TRS trigger based on a medium access control (MAC) command or downlink control information (DCI); and perform the fine time tracking in response to the TRS trigger. In embodiment 6, the one or more processors are configured to determine that the UE-specific RS is an aperiodic RS based on the TRS configuration; determine that a transmission configuration indicator (TCI) command has been received; and perform the fine time tracking after decoding of the transmission configuration indicator (TCI) command. In embodiment 7, the one or more processors are configured to perform the fine time tracking and automatic gain control (AGC) during transmission of the UE-specific RS. In embodiment 8, the one or more processors are configured to receive the TRS configuration during a radio resource control (RRC) procedure involving the first base station. In embodiment 9, the one or more processors are configured to perform the fine time tracking based on a cell-specific RS when the TRS configuration is not received.

[0087] In embodiment 10, a baseband (BB) circuit of a user equipment (UE) device, the BB circuit comprising circuitry for: receiving a tracking reference signal (TRS) configuration from a first carrier of a first base station operating as a primary cell of the UE, the TRS configuration indicating a UE-specific reference signal (RS) corresponding to a second carrier of the first base station or a third carrier of a second base station designated to operate as a secondary cell of the UE; receiving an activation command of the secondary cell from the primary cell; and in response to the activation command, performing a secondary cell activation procedure with the second base station including fine time tracking based on the UE-specific RS. In embodiments 11-18, the BB circuit of embodiment 10 is further modified by applying one or more or any combination of the device features of embodiments 2-9 as features of the BB circuit of embodiment 10.

[0088] In embodiment 19, a method performed by a user equipment (UE) can include: receiving a tracking reference signal (TRS) configuration from a first carrier of a first base station operating as a primary cell of the UE, the TRS configuration indicating a UE-specific reference signal (RS) corresponding to a second carrier of the first base station or a third carrier of a second base station designated to operate as a secondary cell of the UE; receiving an activation command of the secondary cell from the primary cell; and in response to the activation command, performing a secondary cell activation procedure with the second base station including fine time tracking based on the UE-specific RS. In embodiments 20-27, the method of embodiment 19 is further modified by applying one or more or any combination of the features of embodiments 2-9 as features of the method of embodiment 19.

[0089] As Embodiment 28, a user equipment (UE) device can include means for receiving a tracking reference signal (TRS) configuration from a first carrier of a first base station operating as a primary cell of the UE, the TRS configuration indicating a UE-specific reference signal (RS) corresponding to a second carrier of the first base station or a third carrier of a second base station designated to operate as a secondary cell of the UE; means for receiving an activation command of the secondary cell from the primary cell; and means for performing, in response to the activation command, a secondary cell activation procedure with the second base station, the secondary cell activation procedure including fine time tracking based on the UE-specific RS. In Embodiments 29-36, the UE of Embodiment 28 is further modified by applying one or more or any combination of the features of Embodiments 2-9 as features (e.g., means for) of Embodiment 28.

[0090] In Embodiment 37, a computer-readable medium includes instructions that, when executed by a processor, cause the processor to: receive a tracking reference signal (TRS) configuration from a first carrier of a first base station operating as a primary cell of the UE, the TRS configuration indicating a UE-specific reference signal (RS) corresponding to a second carrier of the first base station or a third carrier of a second base station designated to operate as a secondary cell of the UE; receive an activation command of the secondary cell from the primary cell; and in response to the activation command, perform a secondary cell activation procedure with the second base station, the secondary cell activation procedure including fine time tracking based on the UE-specific RS. In Embodiments 38-45, the computer-readable medium of Embodiment 37 is further modified by applying one or more or any combination of the device features of Embodiments 2-9 as features of the computer-readable medium of Embodiment 37.

[0091] The above description of illustrative examples, implementations, aspects, etc. of the subject disclosure, including the contents of the Abstract, is not intended to be exhaustive or to limit the disclosed aspects to the precise forms disclosed. While specific examples, implementations, aspects, etc. are described herein for illustrative purposes, various modifications are possible within the scope of such examples, implementations, aspects, etc. as the skilled artisan will recognize.

[0092] To the extent that the subject matter of this disclosure includes concepts that can not be prior art by virtue of their having been published (e.g., as suggested above), nothing in this disclosure is to be construed as an admission that the concepts are not entitled to antedate prior art. To the extent that section headings are used, they should not be construed as necessarily limiting the subject matter described. Also, the use of examples, or offering a choice of several alternatives in certain instances is not to be understood as limiting; any feature, structure, or characteristic not expressly excluded is deemed essential. The examples described herein are intended merely to be illustrative and are not intended to suggest any limitation on the scope of the disclosure. Words of approximation such as “about,” “substantially,” or “approximately” mean ±10% of the value stated, unless otherwise stated.

[0093] In particular regard to the various functions performed by the above described components or structures (assemblies, devices, circuits, systems, etc.), the terms (including a reference to a “means”) used to describe certain aspects, structures, or

[0094] As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. Moreover, articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. Additionally, to the extent that the terms “includes,” “including,” “has,” “having,” “with,” or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” Further, to the extent that the discussion has been directed to one or more numbered items (e.g., “first X,” “second X,” etc.), generally, the one or more numbered items can be different or they can be the same, but in some instances, the context can indicate that they are different or that they are the same.

[0095] It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled in a way to minimize risk of unintentional or unauthorized access or use, and the nature of authorization should be clearly expressed to users.

Claims

1. A user equipment (UE) device, comprising: A radio frequency (RF) circuit configured to communicate with a wireless communication network; A memory device configured to store instructions; and One or more processors, connected to the RF circuitry and the memory device, and configured to execute the instructions to: The RF circuit receives a tracking reference signal (TRS) configuration from a first carrier of a first base station operating as the primary cell of the UE. The TRS configuration indicates a UE-specific reference signal (RS) corresponding to a second carrier of the first base station or a third carrier of a second base station designated as the secondary cell of the UE. The activation command of the secondary cell is received from the primary cell via the RF circuit. as well as In response to the activation command, a secondary cell activation process for the second base station is performed, the secondary cell activation process including fine time tracking based on the UE-specific RS.

2. The UE according to claim 1, wherein the one or more processors are configured to: The periodicity of the UE-specific RS is determined based on the TRS configuration; and The fine-grained time tracking is performed periodically according to the specific RS of the UE.

3. The UE according to claim 1, wherein the one or more processors are configured to: Based on the TRS configuration, it is determined that the UE-specific RS is an aperiodic RS; and The fine-grained time tracking is performed based on the transmission time of the activation command.

4. The UE of claim 3, wherein the fine-grained time tracking is performed based on the duration associated with the Hybrid Automatic Repeat Request (HARQ) message associated with the activation command.

5. The UE of claim 1, wherein the one or more processors are configured to: TRS triggering is detected based on Media Access Control (MAC) commands or Downlink Control Information (DCI); and The fine-grained time tracking is performed in response to the TRS trigger.

6. The UE of claim 1, wherein the one or more processors are configured to: Based on the TRS configuration, it is determined that the UE-specific RS is a non-periodic RS; It has been confirmed that the Transport Configuration Indicator (TCI) command has been received; and The fine-grained time tracking is performed after the Transmission Configuration Indicator (TCI) command is decoded.

7. The UE of claim 1, wherein the one or more processors are configured to: The fine time tracking and automatic gain control (AGC) are performed during the transmission of the UE-specific RS.

8. The UE of claim 1, wherein the one or more processors are configured to: The TRS configuration is received during the Radio Resource Control (RRC) process involving the first base station.

9. The UE of claim 1, wherein the one or more processors are configured to: When the TRS configuration is not received, fine time tracking is performed based on the cell-specific RS.

10. A baseband (BB) circuit for a user equipment (UE) device, the BB circuit comprising circuitry for operating as follows: A tracking reference signal (TRS) configuration is received from a first carrier of a first base station operating as the primary cell of the UE, the TRS configuration indicating a UE-specific reference signal (RS) corresponding to a second carrier of the first base station or a third carrier of a second base station designated as the secondary cell of the UE. Receive the activation command for the secondary cell from the primary cell; as well as In response to the activation command, a secondary cell activation process for the second base station is performed, the secondary cell activation process including fine time tracking based on the UE-specific RS.

11. The BB circuit of claim 10, further comprising circuitry for the following operation: The periodicity of the UE-specific RS is determined based on the TRS configuration; and The fine-grained time tracking is performed periodically according to the specific RS of the UE.

12. The BB circuit of claim 10, further comprising circuitry for the following operation: Based on the TRS configuration, it is determined that the UE-specific RS is an aperiodic RS; and The fine-grained time tracking is performed based on the transmission time of the activation command.

13. The BB circuit of claim 12, wherein the fine time tracking is performed based on the duration associated with the Hybrid Automatic Repeat Request (HARQ) message associated with the activation command.

14. The BB circuit of claim 10, further comprising circuitry for the following operation: TRS triggering is detected based on Media Access Control (MAC) commands or Downlink Control Information (DCI); and The fine-grained time tracking is performed in response to the TRS trigger.

15. The BB circuit of claim 10, further comprising circuitry for the following operation: Based on the TRS configuration, it is determined that the UE-specific RS is a non-periodic RS; It has been confirmed that the Transport Configuration Indicator (TCI) command has been received; and The fine-grained time tracking is performed after the Transmission Configuration Indicator (TCI) command is decoded.

16. The BB circuit of claim 10, further comprising circuitry for the following operation: The fine time tracking and automatic gain control (AGC) are performed during the transmission of the UE-specific RS.

17. The BB circuit of claim 10, further comprising circuitry for the following operation: The TRS configuration is received during the Radio Resource Control (RRC) process involving the first base station.

18. The BB circuit of claim 10, further comprising circuitry for the following operation: When the TRS configuration is not received, fine time tracking is performed based on the cell-specific RS.

19. A method performed by a user equipment (UE), the method comprising: A tracking reference signal (TRS) configuration is received from a first carrier of a first base station operating as the primary cell of the UE, the TRS configuration indicating a UE-specific reference signal (RS) corresponding to a second carrier of the first base station or a third carrier of a second base station designated as the secondary cell of the UE. Receive the activation command for the secondary cell from the primary cell; as well as In response to the activation command, a secondary cell activation process for the second base station is performed, the secondary cell activation process including fine time tracking based on the UE-specific RS.

20. The method of claim 19, further comprising: The periodicity of the UE-specific RS is determined based on the TRS configuration; as well as The fine-grained time tracking is performed periodically according to the specific RS of the UE.

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