SYSTEM AND METHOD FOR UPLINK TIMING ALIGNMENT FOR INTER-CELL MOBILITY - Patent application

Abstract

A system, method, apparatus, or computer-readable medium for uplink timing alignment for inter-cell mobility is presented. A wireless communication node of a candidate cell for a wireless communication device can transmit a configuration associated with the candidate cell to the wireless communication device. The wireless communication node can receive a transmission transmitted by the wireless communication device in accordance with the configuration. In one embodiment, the configuration comprises a random access channel configuration, and the transmission comprises a physical random access channel (PRACH) transmission.

Description

[Technical Field]

[0001] Technical Field The present disclosure relates generally to wireless communications, including, but not limited to, systems and methods for uplink timing alignment for inter-cell mobility. [Background technology]

[0002] background The 3rd Generation Partnership Project (3GPP®), a standards organization, is currently specifying a new radio interface called 5G New Radio (5G NR) and the Next Generation Packet Core Network (NG-CN or NGC). 5G NR will have three main components: the 5G Access Network (5G-AN), the 5G Core Network (5GC), and the User Equipment (UE). To facilitate the enablement of different data services and requirements, elements of the 5GC, also known as network functions, have been simplified, and some of them are software-based so they can be adapted as needed. Summary of the Invention [Means for solving the problem]

[0003] overview The exemplary embodiments disclosed herein are directed to solving problems associated with one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent from a review of the following detailed description in conjunction with the accompanying drawings. In accordance with various embodiments, exemplary systems, methods, devices, and computer program products are disclosed herein. It will be understood, however, that these embodiments are presented by way of example, and not limitation, and that various modifications to the disclosed embodiments can be made while remaining within the scope of the present disclosure, as will be apparent to those skilled in the art upon reading this disclosure.

[0004] At least one aspect relates to a system, method, apparatus, or computer-readable medium for uplink timing alignment for inter-cell mobility. A wireless communication node (e.g., a base station (BS), a gNB, or a transmit / receive point (TRP)) of a candidate cell for a wireless communication device can transmit / transmit / provide / communicate / signal a configuration associated with the candidate cell to the wireless communication device (e.g., a UE). The wireless communication node can receive / obtain / collect / acquire transmissions transmitted by the wireless communication device in accordance with the configuration.

[0005] In some implementations, the configuration may comprise / include configuration of a random access channel. The transmission may comprise a physical random access channel (PRACH) transmission. In some implementations, the wireless communication device may initiate / initiate / perform a random access procedure associated with the candidate cell according to the configuration or according to a message from the wireless communication node indicating at least one PRACH transmission parameter for the candidate cell.

[0006] In some implementations, the configuration may include a maximum number of PRACH transmissions associated with the random access procedure for TA acquisition of the candidate cell. When the number of PRACH transmissions associated with the random access procedure reaches the maximum number, the random access procedure may be considered to have completed unsuccessfully (e.g., failed).

[0007] In some implementations, a wireless communication node may receive a message indicating that a random access procedure has been initiated to obtain timing advance (TA) related information of a candidate cell from a wireless communication device. In some implementations, at least one of the following may occur: after transmitting the message, the wireless communication device may not detect (e.g., avoid / skip / ignore detection) a downlink control information (DCI) format associated with scheduling a random access response (RAR) associated with the random access procedure or may not receive the RAR; after transmitting the message, the wireless communication device may not detect a DCI format associated with scheduling a physical downlink shared channel (PDSCH) that includes a user equipment (UE) contention resolution identity or may not receive the PDSCH that includes the UE contention resolution identity; after transmitting the message, the wireless communication device may not detect a DCI format with cyclic redundancy check (CRC) bits scrambled by a corresponding MsgB radio network temporary identifier (RNTI) or may not receive the MsgB; and / or the message may comprise at least one of a cell RNTI (C-RNTI), a random access RNTI (RA-RNTI), an MsgB RNTI, a random access preamble index, and / or a candidate cell index.

[0008] In some implementations, the wireless communication node may transmit a message to the wireless communication device indicating that it has finished or completed the random access procedure or successfully received the PRACH transmission after receiving Msg1, Msg3, or MsgA, and wherein at least one of the following occurs: the wireless communication device may not detect a downlink control information (DCI) format associated with scheduling of a random access response (RAR) associated with the random access procedure or may not receive the RAR; the wireless communication device may not detect a DCI format associated with scheduling of a physical downlink shared channel (PDSCH) including a user equipment (UE) contention resolution identity or may not receive a PDSCH including a UE contention resolution identity; the wireless communication device may not detect a DCI format with cyclic redundancy check (CRC) bits scrambled by a corresponding MsgB radio network temporary identifier (RNTI) or may not receive an MsgB; and / or the message is a Cell RNTI (C-RNTI), a Random Access RNTI (RA-RNTI), or an MsgB. The DCI format may have CRC bits scrambled by the RNTI, or an indication field with bits set to a specific value, or a specific indication field, or a DCI format with specific Medium Access Control Control Element (MAC CE) signaling.

[0009] In some implementations, at least one of the following occurs: the wireless communication node may send a random access response (RAR) message to the wireless communication device indicating the termination or successful completion of the random access procedure, and the RAR message may indicate at least one of a physical cell index (PCI), a candidate cell index, a flag for completing or terminating the random access procedure, and / or timing advance (TA) related information; the wireless communication node may send a configuration to the wireless communication device to enable or disable the wireless communication device from performing the partial random access procedure, and when the partial random access procedure is enabled, perform one or more steps / procedures / functions discussed herein and / or perform the partial random access procedure. is disabled, the random access may be performed according to a two-step type random access or a four-step type random access procedure; the wireless communication node may transmit one or more RAR messages to the wireless communication device, each of the one or more RAR messages may indicate TA-related information associated with a corresponding candidate cell, and the wireless communication device may determine an uplink transmission timing associated with the corresponding candidate cell indicated by the cell switch message based at least on the TA-related information associated with the corresponding candidate cell; and / or the wireless communication node may transmit a cell switch message to the wireless communication device, the cell switch message indicating at least one of a cell index and / or the TA-related information associated with the cell index.

[0010] In some implementations, at least one of the following is true: the wireless communication node for transmitting the random access preamble is capable of determining a random access network temporary identifier (RA-RNTI) associated with the PRACH occasion on which the random access preamble is transmitted as a function of a candidate cell index (cell_id) associated with the transmission of the random access preamble; and / or the wireless communication node for transmitting the MsgA is capable of determining a MSGB network temporary identifier (RNTI) associated with the PRACH occasion on which the random access preamble is transmitted as a function of cell_id and cell_total, where cell_total may be the maximum number of supported candidate cells according to the capabilities of the wireless communication device, or the number of configured candidate cells, or a defined value, and cell_id is an integer value greater than or equal to 0 and less than or equal to the value of cell_total, and the defined value is one from {1, 2, 3, 4, 5, 6, 7}.

[0011] In some implementations, a wireless communication node may transmit a configuration to a wireless communication device to configure the wireless communication device with a timing advance (TA) related timer for a candidate cell, wherein upon expiration of the timing advance related timer, the wireless communication device may initiate a random access procedure associated with the candidate cell.

[0012] In some implementations, at least one of the following may be true: the configuration may comprise a configuration of one or more sounding reference signal (SRS) resources or SRS resource sets associated with timing advance (TA) acquisition; the transmission may comprise an SRS transmission; the SRS transmission may be for uplink timing advance acquisition for the candidate cell; and / or the one or more SRS resources or SRS resource sets may be associated with the candidate cell and / or at least one of the candidate cell's downlink reference signals (DL-RS).

[0013] In some implementations, the wireless communication node may receive an SRS transmission from a wireless communication device, and at least one of the following: the SRS transmission may correspond to SRS activation or deactivation medium access control element (MAC CE) signaling or downlink control information (DCI) signaling; a field within the SRS activation or deactivation MAC CE signaling or DCI signaling may indicate that the SRS transmission is activated or triggered for timing advance acquisition of the candidate cell; and / or the SRS transmission may be associated with the candidate cell.

[0014] In some implementations, the wireless communication device may determine uplink transmission timing of an SRS transmission associated with timing advance acquisition for the candidate cell based at least on a timing advance value and downlink timing, where the timing advance value may comprise (i) 0, (ii) a timing advance value associated with the source cell, (3) a timing advance value associated with a cell different from the candidate cell, and / or (4) a timing advance value associated with the candidate cell, and / or the downlink timing may comprise (i) downlink timing associated with the source cell, (ii) downlink timing associated with the candidate cell, and / or (iii) downlink timing associated with a cell different from the candidate cell.

[0015] In some implementations, at least one of the following may occur: after an SRS transmission for uplink timing advance acquisition, the wireless communication device may receive a message indicating an index of the candidate cell, and cancel the activated or triggered transmission of the SRS for uplink timing advance acquisition associated with the candidate cell; or the wireless communication device may not receive the message indicating an index of the candidate cell within a time period associated with the SRS transmission for uplink timing advance acquisition associated with the candidate cell, the time period may be configured for an SRS resource, SRS resource set, or candidate cell associated with the SRS transmission, and may transmit another message to the wireless communication node indicating that uplink timing advance acquisition for the candidate cell failed.

[0016] At least one aspect relates to a system, a method, an apparatus, or a computer-readable medium. A wireless communication device (e.g., a UE) can receive a configuration associated with a candidate cell from a wireless communication node (e.g., a BS, a gNB, or a TRP). The wireless communication device can send a transmission to the wireless communication node according to the configuration.

[0017] The systems and methods presented herein include novel approaches for uplink timing adjustment for inter-cell mobility. Specifically, the systems and methods presented herein consider novel solutions for a UE (e.g., a wireless communication device) to acquire / obtain / receive a timing advance value of at least one candidate cell in instances / cases / scenarios in which the UE is requesting a cell switch. For example, the systems and methods of the technical solutions may provide techniques for performing a partial random access procedure for acquiring a timing advance value, defining a sounding reference signal (SRS) transmission-based method / procedure / step / function for acquiring a timing advance value, and / or defining a downlink timing differential-based method for acquiring a timing advance value. [Brief explanation of the drawings]

[0018] BRIEF DESCRIPTION OF THE DRAWINGS Various exemplary embodiments of the present solution will be described in detail below with reference to the following figures or drawings. The drawings are provided for illustrative purposes only and merely illustrate exemplary embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the drawings should not be considered as limiting the breadth, scope, or applicability of the present solution. It should be noted that for clarity and ease of explanation, these drawings are not necessarily drawn to scale.

[0019] [Figure 1] 1 illustrates an exemplary cellular communication network in which the techniques disclosed herein may be implemented, according to one embodiment of the present disclosure.

[0020] [Figure 2] 1 shows a block diagram of an exemplary base station and user equipment device in accordance with some embodiments of the present disclosure.

[0021] [Figure 3] 1 illustrates a deployment scenario for inter-cell mobility according to an example embodiment.

[0022] [Figure 4] 1 illustrates a block diagram of timing advance management for inter-cell mobility according to an example embodiment.

[0023] [Figure 5] 1 illustrates a flow diagram of a method for uplink timing alignment for inter-cell mobility, according to an example embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Detailed Description Various exemplary embodiments of the present solution are described below with reference to the accompanying drawings to enable those skilled in the art to make and use the solution. As will be apparent to those skilled in the art, after reading this disclosure, various changes or modifications can be made to the examples described herein without departing from the scope of the solution. Thus, the present solution is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, any specific order or hierarchy of steps in the methods disclosed herein is merely an example approach. Based on design preferences, the specific order or hierarchy of steps in a disclosed method or process can be rearranged while remaining within the scope of the solution. Thus, those skilled in the art will appreciate that the methods and techniques disclosed herein present various steps or operations in a sample order, and that the solution is not limited to the specific order or hierarchy presented, unless otherwise specified.

[0025] 1. Mobile communication technology and environment 1 illustrates an exemplary wireless communication network and / or system 100 in which the techniques disclosed herein may be implemented, according to one embodiment of the present disclosure. In the following discussion, the wireless communication network 100 may be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, and is referred to herein as “network 100.” Such exemplary network 100 includes a base station 102 (hereinafter “BS 102,” also referred to as a wireless communication node) and a user equipment device 104 (hereinafter “UE 104,” also referred to as a wireless communication device) that can communicate with each other via a communication link 110 (e.g., a wireless communication channel), and a cluster of cells 126, 130, 132, 134, 136, 138, and 140 that overlap a geographic area 101. In FIG. 1, the BS 102 and the UE 104 are contained within the respective geographic boundaries of cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating in its assigned bandwidth to provide adequate radio coverage to intended users.

[0026] For example, the BS 102 may operate with an assigned channel transmission bandwidth to provide adequate coverage to the UE 104. The BS 102 and the UE 104 may communicate via downlink radio frames 118 and uplink radio frames 124, respectively. Each radio frame 118 / 124 may be further divided into subframes 120 / 127, which may include data symbols 122 / 128. In this disclosure, the BS 102 and the UE 104 are generally described herein as non-limiting examples of “communication nodes” capable of implementing the methods disclosed herein. Such communication nodes may be capable of wireless and / or wired communication in accordance with various embodiments of the present solution.

[0027] 2 illustrates a block diagram of an exemplary wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM / OFDMA signals) in accordance with some embodiments of the present solution. System 200 may include components and elements configured to support known or conventional operational functions that need not be described in detail herein. In one exemplary embodiment, system 200 may be used to communicate (e.g., transmit and receive) data symbols in a wireless communication environment, such as wireless communication environment 100 of FIG. 1 described above.

[0028] The system 200 generally includes a base station 202 (hereinafter "BS 202") and a user equipment device 204 (hereinafter "UE 204"). The BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each of which is coupled and interconnected as needed via a data communication bus 220. The UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled and interconnected as needed via a data communication bus 240. The BS 202 communicates with the UE 204 via a communication channel 250, which can be any wireless channel or other medium suitable for the transmission of data as described herein.

[0029] As will be appreciated by those skilled in the art, system 200 may further include any number of modules other than those shown in FIG. 2 . Those skilled in the art will appreciate that the various exemplary blocks, modules, circuits, and processing logic described in connection with the embodiments disclosed herein may be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. To clearly illustrate this interchangeability and interchangeability of hardware, firmware, and software, various exemplary components, blocks, modules, circuits, and steps are described generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software may depend on the particular application and design constraints imposed on the overall system. Those familiar with the concepts described herein may implement such functionality in a manner suitable for each particular application, but such implementation decisions should not be construed as limiting the scope of the present disclosure.

[0030] According to some embodiments, the UE transceiver 230 may be referred to herein as an “uplink” transceiver 230, including a radio frequency (RF) transmitter and an RF receiver, each comprising circuitry coupled to an antenna 232. Alternatively, a duplexing switch (not shown) may couple the uplink transmitter or receiver to the uplink antenna in a time-duplexed manner. Similarly, according to some embodiments, the BS transceiver 210 may be referred to herein as a “downlink” transceiver 210, including an RF transmitter and an RF receiver, each comprising circuitry coupled to an antenna 212. Alternatively, a downlink duplexing switch may couple the downlink transmitter or receiver to the downlink antenna 212 in a time-duplexed manner. The operation of the two transceiver modules 210 and 230 may be coordinated in time such that the downlink transmitter is coupled to the downlink antenna 212 at the same time that the uplink receiver circuitry is coupled to the uplink antenna 232 for reception of transmissions over the wireless transmission link 250. Conversely, the operation of the two transceivers 210 and 230 may be coordinated in time such that the uplink transmitter is coupled to the uplink antenna 232 at the same time that the downlink receiver is coupled to the downlink antenna 212 for receiving transmissions over the wireless transmission link 250. In some embodiments, strict time synchronization is achieved with minimal guard times between changes in duplex direction.

[0031] The UE transceiver 230 and the base station transceiver 210 are configured to communicate via a wireless data communication link 250 and cooperate with a suitably configured RF antenna arrangement 212 / 232 capable of supporting a particular wireless communication protocol and modulation scheme. In some exemplary embodiments, the UE transceiver 210 and the base station transceiver 210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards. However, it will be understood that the present disclosure is not necessarily limited in application to a particular standard and associated protocol. Rather, the UE transceiver 230 and the base station transceiver 210 may be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0032] According to various embodiments, the BS 202 may be, for example, an evolved Node B (eNB), a serving eNB, a target eNB, a femto station, or a pico station. In some embodiments, the UE 204 may be embodied in various types of user devices, such as a mobile phone, a smartphone, a personal digital assistant (PDA), a tablet, a laptop computer, a wearable computing device, etc. The processor modules 214 and 236 may be implemented or realized using a general-purpose processor, a content-addressable memory, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. As such, a processor may be realized as a microprocessor, a controller, a microcontroller, a state machine, etc. A processor may also be implemented as a combination of computing devices, such as a combination of a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other such configuration.

[0033] Furthermore, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, firmware, software modules executed by processor modules 214 and 236, respectively, or any practical combination thereof. Memory modules 216 and 234 may be realized as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In this regard, memory modules 216 and 234 may be coupled to processor modules 210 and 230, respectively, such that processor modules 210 and 230 can read information from and write information to memory modules 216 and 234, respectively. Memory modules 216 and 234 may also be integrated into respective processor modules 210 and 230. In some embodiments, memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during execution of instructions to be executed by processor modules 210 and 230, respectively. Additionally, memory modules 216 and 234 may each include non-volatile memory for storing instructions executed by processor modules 210 and 230, respectively.

[0034] The network communications module 218 generally represents the hardware, software, firmware, processing logic, and / or other components of the base station 202 that enable bidirectional communications between the base station transceiver 210 and other network components and communications nodes configured to communicate with the base station 202. For example, the network communications module 218 may be configured to support Internet or WiMAX traffic. In a typical deployment, without limitation, the network communications module 218 provides an 802.3 Ethernet interface to enable the base station transceiver 210 to communicate with conventional Ethernet-based computer networks. As such, the network communications module 218 may include a physical interface for connecting to a computer network (e.g., a mobile switching center (MSC)). As used herein with respect to particular operations or functions, the terms “configured for,” “configured to,” and their conjugations refer to devices, components, circuits, structures, machines, signals, etc. that are physically structured, programmed, formatted, and / or arranged to perform particular operations or functions.

[0035] The Open Systems Interconnection (OSI) model (referred to herein as the "Open Systems Interconnection Model") is a conceptual and logical layout that defines network communications used by systems (e.g., wireless communication devices, wireless communication nodes) that are open to interconnection and communication with other systems. The model is divided into seven subcomponents or layers, each of which represents a conceptual collection of services provided to its upper and lower layers. The OSI model also defines logical networks and effectively describes computer packet transfers by using different layer protocols. The OSI model may also be referred to as a seven-layer OSI model or seven-layer model. In some embodiments, the first layer may be the physical layer. In some embodiments, the second layer may be the medium access control (MAC) layer. In some embodiments, the third layer may be the radio link control (RLC) layer. In some embodiments, the fourth layer may be the packet data convergence protocol (PDCP) layer. In some embodiments, the fifth layer may be the radio resource control (RRC) layer. In some embodiments, the sixth layer may be a non-access stratum (NAS) layer or an Internet Protocol (IP) layer, and the seventh layer is some other layer.

[0036] 2. System and method for uplink timing alignment for inter-cell mobility In certain systems, UE mobility (e.g., mobility of a UE 104) may refer to or be defined as a handover from one cell (e.g., an NR cell) to another cell. The handover may be based on or in accordance with measurements of synchronization signals associated with different cells and / or transmission / reception points (TRPs). For certain types of mobility (e.g., Layer 3-based mobility) or systems, downlink (DL) and uplink (UL) synchronization (e.g., DL / UL synchronization) occurs after or following a handover of the UE 104 to another cell, which may result in a relatively large delay in the cell switch. For certain other types of mobility (e.g., Layer 1- and / or Layer 2-based mobility), when the UE 104 is configured for one or more candidate cells, the UE 104 may perform downlink and / or uplink synchronization of the candidate cells prior to or before the cell switch. In this case, the UE may establish downlink and / or uplink synchronization before receiving the cell switch command message, thereby reducing / minimizing cell switch delay.

[0037] Uplink synchronization can ensure or enable the arrival timing of transmissions from multiple UEs 104 to be within an acceptable / satisfactory range and / or ensure that demodulation at the network side (e.g., BS side) is reliable. Uplink synchronization can be based on, followed by, or relying on an indication message / signal from the BS 102 (e.g., network) and / or measurements at the UE side. The indication message can be determined / obtained / acquired / identified at the BS side based on an uplink channel / signal from the UE 104, such as a PRACH and / or SRS, among other types of signals. The measurements at the UE side can be based on the received timing of a downlink signal / channel. When uplink synchronization of one or more candidate cells is to be performed, it may be desirable to obtain (e.g., by the UE 104) a timing advance value associated with each of the candidate cells, such as before or during the cell switch, to reduce / minimize cell switch delay or latency.

[0038] Referring to FIG. 3, a deployment scenario 300 for inter-cell mobility is illustrated. Downlink synchronization and / or uplink synchronization may be one of steps / processes / procedures for ensuring reliable wireless communication in various wireless systems, for example, for reliable communication between at least one UE 104 and at least one BS 102. In a particular scenario, downlink synchronization may be achieved / triggered by or in response to receiving / acquiring / obtaining a primary synchronization signal (PSS) and / or a secondary synchronization signal (SSS). Uplink synchronization may be achieved by or in response to a random access procedure and / or uplink timing alignment maintenance. Uplink timing alignment maintenance may be based on a timing advance command (TAC) transmitted / sent / provided / signaled / communicated by the BS 102.

[0039] 3, when the UE 104 is in communication with a current serving cell (e.g., a source cell or cell currently connected to or serving the UE 104), the UE 104 may be configured for multiple candidate cells. Due to UE mobility (e.g., movement of the UE 104), the UE 104 may desire or be forced to switch from the source cell to a candidate cell. In such a case, the UE 104 may perform / initiate / perform downlink and / or uplink synchronization for at least one candidate cell.

[0040] For a particular UE 104, the particular UE 104 may determine one or more timing advance values ​​according to the number of time alignment groups (TAGs). The BS 102 may configure / set one or more TAGs to indicate at least one TAC of one or more serving cells in a carrier aggregation scenario. Each TAG may include / contain or be configured for one or more serving cells. The BS 102 may transmit at least one TAC associated with at least one TAG to the UE 104. The UE 104 may apply / initiate / execute the TAC to determine / identify the timing advance of various serving cells within or associated with the TAG.

[0041] For each TAG, the UE 104 may obtain an initial timing advance value based on a random access procedure (e.g., by performing a random access procedure). When the UE 104 receives / obtains / acquires a TAC medium access control (MAC) control element (CE) (e.g., a TAC included / encompassed in or provided via a MAC CE), the UE 104 may update / adjust / configure the timing advance value based on or according to the TAC MAC CE and / or the current timing advance value.

[0042] In various aspects discussed herein, the term source cell refers to, corresponds to, or may be described as a serving cell. The term candidate cell may refer to a non-serving cell, a target cell, or a neighboring cell. The terms cell, source cell, or candidate cell index may be represented by, for example, a serving cell index, a physical cell index, or a candidate cell index. The term source cell or candidate cell may include / comprise, describe, or refer to at least one of "information grouping one or more reference signals," "reference signal resource set," "PUCCH resource set," "antenna port group," "physical cell index (PCI)," "TRP-related information," "CORESET pool index," TAG, "UE capability value," and / or "UE capability set." The term MsgB may include or refer to an absolute timing advance command (MAC CE). The term uplink signal may include or correspond to, but is not limited to, at least one of a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a sounding reference signal (SRS), and / or a physical random access channel (PRACH), etc. The term PRACH transmission may refer to an MSG1 transmission, an MSGA transmission, and / or a random access preamble transmission. The term uplink transmission may refer to or correspond to a transmission occasion of an uplink signal, a repetition of an uplink signal, or an uplink signal. The term downlink reference signal (DL-RS) may include, refer to, or correspond to, among other things, a channel state information (CSI) reference signal (RS) and / or a synchronization signal block (SSB). The term timing advance-related information may include / comprise at least one of a cell index, a time alignment group (TAG) index, a timing advance command, a timing advance offset, and / or a timing advance offset command.

[0043] In various arrangements, the cell index can be a serving cell index, a physical cell index, and / or a candidate cell index. The timing advance command can be carried, for example, in the MAC RAR and / or TAC MAC CE to indicate a timing advance adjustment value. A timing advance offset can be configured for the serving cell to adjust uplink transmission timing. The timing advance offset command can be used / configured / provided to indicate a timing advance adjustment offset value between TAC and / or TA values. The term timing advance acquisition can refer to uplink timing alignment.

[0044] A series of techniques or a sequence of techniques for acquiring / obtaining the uplink timing advance value of a candidate cell may be considered in the following aspects: random access procedure-based, SRS transmission-based, and / or downlink timing differential-based procedures / aspects / methods / configurations. In some configurations, in / for a random access procedure-based configuration, the UE 104 may initiate / start a random access procedure associated with the candidate cell for timing advance acquisition. The BS 102 (e.g., the candidate cell's network) may determine timing advance-related information based on a PRACH transmission from the UE 104. The BS 102 may transmit a message / signal / information to the UE 104. The message may be MsgB, Msg2, MAC RAR, and / or MAC CE indicating completion of the random access procedure. The UE 104 may determine the timing advance value or decide to complete the random access procedure based on the message from the BS 102.

[0045] In some configurations, in an SRS transmission-based configuration, the UE 104 may be configured with one or more SRS resources. In this case, the UE 104 may transmit an SRS for uplink timing acquisition of a candidate cell. In response to receiving the SRS, the BS 102 may determine timing advance-related information based on the SRS transmission from the UE 104. The BS 102 may transmit a message to the UE 104, which may be in a TAC MAC CE or MAC CE / Downlink Control Information (DCI) format indicating cancellation / termination of the SRS transmission for uplink timing advance acquisition. The UE 104 may determine a timing advance value or decide to cancel the SRS transmission based on or in accordance with the message from the BS 102.

[0046] In some configurations, in a downlink timing differential-based configuration, the UE 104 may receive one or more downlink reference signals associated with at least one cell. In response to receiving the downlink reference signals, the UE 104 may determine the downlink timing of the cell. The UE 104 may also determine a difference in the downlink timing between a first cell and a second cell. The UE 104 may determine a timing advance value associated with the second cell based on the difference and a timing advance value associated with the first cell. The UE 104 may receive a message (e.g., from the BS 102) indicating timing advance adjustment information. In response to receiving the message, the UE 104 may determine to adjust the timing advance value according to the message.

[0047] In various implementations, the UE 104 can be configured with / for one or more candidate cells (e.g., communicate with one or more BSs 102 associated with different candidate cells). In this case, the UE 104 can perform uplink time alignment for at least one of the one or more candidate cells. The UE 104 can transmit an uplink transmission associated with a first cell and adjust / change / update the transmission timing of the uplink transmission based on the first timing advance-related message. When the UE 104 receives a cell switch message from a respective BS 102 indicating a second cell, the UE 104 can transmit an uplink transmission associated with the second cell and adjust the transmission timing of the uplink transmission based on or in accordance with the second timing advance-related message. In this case, the first cell can be associated with or refer to the source cell, and the second cell can be associated with or refer to one of the candidate cells. The second timing advance related message may be determined / identified based on at least one of the methods / functions / implementations discussed herein (eg, in connection with FIG. 4).

[0048] Referring to FIG. 4, a block diagram 400 of timing advance management for inter-cell mobility is shown. As shown, before / prior to the UE 104 receiving a cell switch command / indication / message, the transmission timing of / for an uplink transmission may be determined by or according to a timing advance value obtained for a source cell (e.g., a current cell serving the UE 104). The UE 104 may acquire / obtain / receive multiple timing advance values ​​for multiple respective candidate cells (e.g., potential cells for cell switching). When or in response to the UE 104 receiving a cell switch command, the UE 104 may determine the transmission timing of the uplink transmission according to the timing advance value obtained for the candidate cell indicated by the cell switch command. The timing advance values ​​for other candidate cells may be cleaned, deemed invalid, discarded, or maintained / retained without further updates.

[0049] In various implementations described herein, when the UE 104 receives a timing advance-related message from a BS 102 associated with a candidate cell, the UE 104 may determine a new timing advance value associated with the candidate cell based on the timing advance-related message and / or based on a current timing advance value associated with the candidate cell. The candidate cell (e.g., to perform / trigger uplink time alignment) may be configured by the BS 102 (e.g., a network device, wireless communication node, gNB, or TRP of a particular candidate cell).

[0050] For example, uplink time alignment may be enabled in the configuration of a candidate cell (e.g., BS 102). In another example, a set of candidate cell indices may be configured to perform uplink time alignment. In various configurations, the number of candidate cells for performing uplink time alignment may correspond to or equal at least one of, for example, a number of candidate cells configured for / for the UE 104, a value according to UE capabilities / settings / performance, a predefined value, and / or a configured value.

[0051] Exemplary Implementation 1: Timing Advance Related Messages Based on Random Access (RA) Procedures In various configurations, the system and method of the technical solutions discussed herein may include determining and / or indicating timing advance-related information associated with a candidate cell based on a random access procedure. The UE 104 may determine a timing advance value associated with a candidate cell based on or in accordance with a message (e.g., timing advance-related information) from the BS 102. The message may be determined by the BS 102 based on a PRACH transmission from the UE 104. The information may be carried in a random access response (RAR) or a cell switch command.

[0052] In some aspects, before initiating / prior to a physical random access procedure, the UE 104 may be configured (e.g., by the BS 102) with one or more random access channel configurations for one or more candidate cells. The random access channel configurations may include at least one of a random access (RA) preamble index, an RA radio network temporary identifier (RNTI), a PRACH resource, a target power level / threshold at the network receiver side (e.g., at the BS side), a maximum number of RA preamble transmissions (e.g., preambleTransMax) made before declaring failure, a synchronization signal block (SSB) index, a candidate cell index, and / or a physical cell index (PCI). To configure the UE 104, for example, the BS 102 (of a candidate cell for the UE 104) may transmit a configuration (e.g., a random access channel configuration) associated with the candidate cell to the UE 104. One or more random access channel configurations for one or more candidate cells may be associated with cell-specific random access parameters configured in RACH-ConfigCommon and / or dedicated random access parameters configured in RACH-ConfigDedicated and / or may be configured individually.

[0053] In some cases, a request for / for a PRACH transmission may be associated with one or more candidate cell configurations and / or an indication of timing advance (TA) acquisition (e.g., an indication to acquire / obtain TA) for one or more candidate cells. The UE 104 may initiate / start / perform a random access procedure associated with a candidate cell based on or in accordance with the candidate cell's random access channel configuration (e.g., sometimes commonly referred to as a configuration) and / or based on a message from the UE 104 (e.g., contention-based RA). In this case, the message from the UE 104 may indicate at least one PRACH transmission parameter for the candidate cell (e.g., non-contention-based RA).

[0054] In some cases, the UE 104 may initiate a random access procedure according to a message (e.g., a PDCCH order) from the BS 102. In this case, the message may include an indication field to provide an indication of initiating / performing a random access procedure for a cell. In one particular configuration, for example, the field may be set / configured to 1 to indicate that a random access procedure is initiated or performed for a candidate cell. The field may be set to 0 to indicate that a random access procedure is initiated or performed for a serving cell. Alternatively, the field may be configured with another binary value indicating whether a random access procedure is initiated for a candidate cell or a serving cell, such as setting the field to 0 or indicating that a random access procedure is initiated for the serving cell or candidate cell, respectively.

[0055] In some implementations, the UE 104 may receive a configuration comprising / including a maximum number of PRACH transmissions associated with the random access procedure for TA acquisition of a candidate cell. The maximum number of PRACH transmissions may be different from the configuration parameter preambleTransMax, which represents the maximum number of RA preamble transmissions made before declaring failure. When the number of PRACH transmissions associated with the random access procedure reaches (or exceeds) the maximum number, the random access procedure may be considered to have completed unsuccessfully (e.g., failed).

[0056] Exemplary Aspect 1 of Implementation Form 1 In various implementations, the UE 104 may transmit / send / provide a message to the BS 102 of the candidate cell to indicate that a random access procedure is initiated / started for TA acquisition (e.g., to acquire TA-related information) of the candidate cell. The message may be carried / included or indicated by at least one of Msg1, Msg3, and / or MsgA. The BS 102 may receive a message from the UE 104 indicating that a random access procedure has been initiated for TA acquisition of the candidate cell.

[0057] If a message is carried or indicated in Msg1, after / following transmission of the message, the UE 104 may not detect (e.g., avoid, skip, bypass, or ignore) a downlink control information (DCI) format associated with the scheduling of the corresponding RAR, and / or the UE 104 may not receive an RAR associated with the random access procedure. In various cases, not detecting certain information or signals (e.g., a DCI format) may include the UE 104 skipping (not performing) the detection process. In further cases, not receiving certain information or signals (e.g., an RAR) may refer to or include the UE 104 indicating to the BS 102 (e.g., via a message) not to transmit / send an RAR or to ignore / skip transmitting an RAR. In some cases, not receiving certain information may include the UE 104 filtering or discarding such information.

[0058] If a message is carried or indicated in Msg3, after transmission of the message, the UE 104 may not detect a DCI format associated with scheduling of a physical downlink shared channel (PDSCH) that includes a UE contention resolution identity and / or may not receive a PDSCH that includes a UE contention resolution identity. If a message is carried or indicated in MsgA, after transmission of the message, the UE 104 may not detect a DCI format (e.g., DCI format 1_0) with cyclic redundancy check (CRC) bits scrambled by a corresponding MsgB radio network temporary identifier (RNTI) and / or may not receive MsgB. In some cases, the UE 104 may not detect or receive multiple pieces of information or combinations of information, for example, when multiple messages (e.g., more than one of Msg1, Msg3, and / or MsgA) are indicated.

[0059] The random access procedure may be considered successfully completed / performed / executed after transmission of a message by the UE 104. The message may include / comprise at least one of a Cell RNTI (C-RNTI), an RA-RNTI, an MsgB-RNTI, a random access preamble index, and / or a candidate cell index. In some cases, when the UE 104 determines a PRACH transmission associated with a PRACH occasion or a random access preamble configured for a candidate cell (e.g., Msg1), the UE 104 may not receive, for example, an RAR message associated with the PRACH transmission.

[0060] In some implementations, the UE 104 may receive / obtain / acquire a message from the BS 102 of the candidate cell that may indicate or indicate that the random access procedure has been terminated / cancelled or completed (e.g., successfully terminated or completed) and / or that a PRACH transmission has been successfully received after transmission of at least one of Msg1, Msg3, and / or MsgA.

[0061] Subsequently, if a message is received (from BS 102) after transmission of Msg1, UE 104 may not detect the DCI format associated with the scheduling of the corresponding RAR associated with the random access procedure and / or may not receive the RAR associated with the random access procedure. If a message is received after transmission of Msg3, UE 104 may not detect the DCI format associated with the scheduling of the PDSCH including the UE Contention Resolution Identity and / or may not receive the PDSCH including the UE Contention Resolution Identity. If a message is received after transmission of MsgA, UE 104 may not detect the DCI format (e.g., DCI format 1_0) with CRC bits scrambled by the corresponding MsgB-RNTI and / or may not receive MsgB.

[0062] In some cases, the message may have / include / contain a DCI format with CRC bits scrambled by the C-RNTI, RA-RNTI, and / or MSGB-RNTI, a DCI format with bits in the indication field set to a specific or predetermined / predefined / configured value, and / or a DCI format that includes a specific indication field or a specific MAC CE. For example, when the UE 104 receives / obtains a DCI format with CRC bits scrambled by the RA-RNTI and bits in the modulation and coding scheme (MCS) field in the DCI format are set to represent an MCS index (e.g., reserved in a predefined table), the UE 104 may not receive an RAR message associated with the RA-RNTI.

[0063] In another example, when the UE 104 receives a DCI format including a completingRA field indicating that the random access procedure will be completed after the transmission of Msg1, the UE 104 may not receive an RAR message associated with that DCI format. In a further example, when the UE 104 receives a TA MAC CE including a cell identity or a list of cell identities, the UE 104 may consider the random access procedure associated with the cell index(es) to have been successfully completed. In some cases, the TA MAC CE may include / comprise one or more timing advance related information, and each timing advance related information may be associated with at least one cell among the one or more cell identities, such as in / from a list of cell identities.

[0064] In some implementations, the UE 104 may receive a RAR message from the BS 102. In this case, in response to receiving the RAR message, the UE 104 may consider the random access procedure to have been successfully completed or terminated according to the RAR message. The RAR message may indicate / provide at least one of a PCI, a candidate cell index, a flag (whether to complete the random access procedure), and / or timing advance-related information. The UL grant field and / or the temporary C-RNTI field may be reserved or absent in the RAR message.

[0065] In some cases, the UE 104 may be configured (e.g., according to a configuration received by the BS 102) to enable or disable performing a partial random access procedure for an individual candidate cell. For example, if performing a partial random access procedure is enabled, at least one of the functions / implementations described above may be performed for the candidate cell. In another example, if performing a partial random access procedure is disabled, the UE 104 may perform / execute the random access procedure for the candidate cell as a two-step type random access or a four-step type random access. In this example, if performing a random access procedure is disabled, the UE 104 may not perform one or more (or any) of the functions described above.

[0066] In some implementations, the UE 104 may receive one or more RAR messages from the BS 102. Each of the RAR messages may indicate individual timing advance-related information associated with a corresponding candidate cell. The UE 104 may determine an uplink transmission timing associated with the cell indicated by the cell switch message based on or in accordance with the timing advance-related information associated with the corresponding candidate cell.

[0067] In some aspects, the UE 104 may receive a cell switch message from the BS 102 indicating a cell index. The cell index may be associated with one of the configured candidate cells. The cell switch message may indicate timing advance-related information associated with the cell index. In some cases, if the random access procedure is performed / executed as a two-step type random access or a four-step type random access, the timing advance-related information may or may not be present. In some other cases, if the random access procedure is performed according to the above implementations, e.g., if the random access procedure is completed in advance, the timing advance-related information may be present.

[0068] In some implementations described herein, completing the random access procedure can correspond to or refer to terminating the random access procedure and / or canceling various later steps of the random access procedure. In certain implementations described herein, receiving / obtaining a message (e.g., from BS 102) indicating completing / terminating the random access procedure or successfully receiving a PRACH transmission, an RAR message, and / or a cell switch message can be associated with at least one of a TCI state, a spatial relationship, a resource set for DL-RS, a search space, a CORESET, and / or a CORESET pool that can be associated with the source cell or the candidate cell.

[0069] Exemplary Aspect 2 of Implementation Form 1 In some configurations, for transmission of a random access preamble, the Random Access Network Temporary Identifier (RA-RNTI) associated with the PRACH occasion on which the random access preamble is transmitted / provided / sent may be calculated as RA-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id + 14 × 80 × 8 × 2 × cell_id. For example, BS 102 may determine the RA-RNTI as a function of the index (cell_id) of the candidate cell associated with the transmission of the random access preamble.

[0070] In some implementations, for an MsgA transmission, the MSGB-RNTI associated with the PRACH occasion on which the random access preamble is transmitted may be calculated as MSGB-RNTI=1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id+14×80×8×2×cell_id+14×80×8×2×cell_total. For example, BS 102 may determine this MSGB-RNTI as a function of cell_id and cell_total.

[0071] In certain implementations described herein, s_id may include, correspond to, or refer to an index (e.g., an integer value) of the first orthogonal frequency division multiplexing (OFDM) symbol of the PRACH occasion (e.g., 0≦s_id<14). t_id may be an index of the first slot of the PRACH occasion within the system frame (e.g., 0≦t_id<80). f_id may be an index of the PRACH occasion in the frequency domain (e.g., 0≦f_id<8). ul_carrier_id may be a UL carrier identifier (e.g., an index or integer value) used for random access preamble transmission (e.g., 0 for the NUL carrier, 1 for the SUL carrier, or vice versa, depending on the configuration).

[0072] The BS 102 may determine the parameter cell_total by or based on the UE 104's capabilities, the configured number of candidate cells, and / or the maximum number of candidate cells (supported) according to a defined / fixed / configured value. The defined / fixed value may be one of / from {1,2,3,4,5,6,7} and / or configured to be one of {1,2,3,4,5,6,7}. The parameter cell_id may be an integer value greater than or equal to 0 (e.g., an index of a cell associated with a random access preamble transmission), for the source cell and / or other candidate cells (e.g., not the corresponding candidate cell associated with an individual BS 102). The parameter cell_id may be an integer value less than or equal to the value of cell_total (e.g., 0≦cell_id≦cell_total). In some cases, the UE capability may be represented by maxNumberTA-Mobility.

[0073] Exemplary Aspect 3 of Implementation Form 1 In some aspects, the UE 104 may not receive a RAR message associated with the candidate cell, a message indicating that the random access procedure is complete, and / or a message indicating successful reception of a PRACH transmission after / following receiving a cell switch command. In some implementations, the UE 104 may be configured with a timing advance-related timer for the candidate cell. For example, the BS 102 may send / transmit / provide a configuration for configuring the UE 104 with a timing advance-related timer for the candidate cell. In this case where the timing advance-related timer is configured, when the UE 104 receives at least one of the timing advance-related information, the message indicating that the random access procedure is complete, and / or the message indicating successful reception of a PRACH transmission, the MAC entity may initiate / start, restart, or stop / cancel / terminate the timing advance-related timer. When the timing advance-related timer expires / times out, the UE 104 may initiate a random access procedure associated with the candidate cell.

[0074] In some implementations, the UE 104 may be configured with a duration value (e.g., a predetermined / predefined period) for a candidate cell. In this case, when the duration since the most recent / last / previous transmission of Msg1 and / or MsgA is greater than the duration value, or when the duration since the last reception / acquisition of timing advance-related information, a message indicating that random access is completed, and / or a message indicating successful reception of a PRACH transmission is greater than (or equal to) the duration value, the UE 104 may initiate a random access procedure associated with the candidate cell. The duration value may be configured to 1 millisecond or more, 1 subslot or more, 1 slot or more, 1 subframe or more, and / or 1 frame or more, such as according to a configuration from the BS 102.

[0075] Exemplary Implementation 2: Sounding Reference Signal (SRS) Based Timing Advance Related Messages In various configurations, the systems and methods of the technical solutions can determine and / or indicate timing advance related information associated with a candidate cell based on or in accordance with transmission and / or reception of sounding reference signals (SRSs). The timing advance related message / signal associated with a candidate cell (of an individual BS 102 or of the network) can be determined based on a message from the BS 102. The message can be determined by the BS 102 based on an SRS transmitted / provided from the UE 104. The message can be carried in at least one of MAC CE and / or DCI formats, among other signaling.

[0076] Exemplary Embodiment 1 of Implementation Form 2 In some aspects, prior to or before transmission of the SRS, the UE 104 may be configured with one or more SRS resources or SRS resource sets associated with timing advance acquisition. For example, configuration from the BS 102 to the UE 104 may include configuration of one or more SRS resources or SRS resource sets associated with timing advance acquisition.

[0077] The UE 104 may be configured with a list of SRS-Resources, a list of SRS-PosResources, a list of SRS-TAResources, a list of SRS-ResourceSets, a list of SRS-PosResourceSets, and / or a list of SRS-TAResourceSets. Each resource set (e.g., an SRS resource set) may provide / indicate or define, among other information, a set of SRS-Resources, SRS-PosResources, and / or SRS-TAResources. One or more SRS resources or SRS resource sets associated with timing advance acquisition may be related / associated, for example, with a list of SRS-TAResources and / or SRS-TAResourceSets. In some cases, one or more SRS resources or SRS resource sets associated with timing advance acquisition may be associated with a candidate cell and / or at least one of the candidate cell's downlink reference signals (DL-RS).

[0078] In some cases, the UE 104 may transmit / send an SRS transmission to the BS 102 of the candidate cell (e.g., using one or more SRS resources or SRS resource sets). The SRS transmission may correspond to SRS activation or deactivation MAC CE and / or DCI signaling or format. In various cases, the SRS transmission may be associated with the candidate cell. A field in the SRS activation or deactivation MAC CE or DCI signaling may indicate that the SRS transmission has been activated / activated / enabled or triggered for timing advance acquisition of the candidate cell.

[0079] In some other cases, the UE 104 may transmit an SRS transmission for uplink timing advance acquisition, for example, if the period since the last transmission of the SRS for uplink timing advance acquisition is greater than (or equal to) a threshold value or if the period (e.g., a time limit) since the last reception of a network message (e.g., a message from the BS 102) is greater than (or equal to) a threshold value. The threshold value may be configured, predetermined, or predefined for individual candidate cells and / or may be predefined based on or according to the configuration of the individual candidate cells. The network message may indicate a timing advance-related message associated with the candidate cell or candidate cell index and / or may indicate that the SRS transmission for uplink timing advance acquisition was successfully received.

[0080] In some implementations, the UE 104 may be configured with a timing advance-related timer for a candidate cell. The timer may start or restart when the UE 104 receives a message (e.g., a network message) from the BS 102. If the timer expires, the UE 104 may transmit / provide / send an SRS (transmission) for uplink timing advance acquisition for the candidate cell. The network message may indicate timing advance-related information (or message) associated with the candidate cell or candidate cell index and / or may indicate that the SRS transmission for uplink timing advance acquisition was successfully received.

[0081] Exemplary Aspect 2 of Implementation Form 2 In some aspects, the UE 104 may determine the uplink transmission timing of the SRS transmission associated with timing advance acquisition for the candidate cell based on or in accordance with the timing advance value and / or downlink timing. In some configurations, the timing advance value may include, correspond to, or be one of: 0, a timing advance value (e.g., an integer value) associated with the source cell, a timing advance value associated with a cell (e.g., of the BS 102) different from the candidate cell, or a timing advance value associated with the candidate cell. The UE 104 may determine the timing advance value associated with the candidate cell according to or based on the steps / procedures / functions described in connection with at least one of Example Implementation 1 or Example Implementation 3.

[0082] In some configurations, the downlink timing may include or be one of downlink timing associated with the source cell, downlink timing associated with the candidate cell, or downlink timing associated with a cell different from the candidate cell. In some cases, the UE 104 may determine the transmit power for the SRS transmission based on open-loop power control parameters configured for the SRS transmission and / or a path loss calculated / computed / determined by the UE 104 using a reference signal associated with the SRS transmission.

[0083] In some cases, the UE 104 may determine the transmit power for the SRS transmission based on open-loop power control parameters configured for the SRS transmission and / or a path loss calculated by the UE 104 using a reference signal associated with the SRS transmission and TPC commands included / filed in the DCI signaling / format. The DCI signaling may be DCI format 2_3, a DCI triggering / activating the SRS transmission, a DCI associated with the latest / most recent PUSCH transmission before the SRS transmission, and / or a DCI format for a PDCCH order.

[0084] Exemplary Aspect 3 of Implementation Form 2 In some aspects, after an SRS transmission for uplink timing advance acquisition, the UE 104 may receive a message / information / signal indicating an index of the candidate cell. The UE 104 may cancel / terminate the activated / triggered transmission of the SRS for uplink timing advance acquisition associated with the candidate cell. In some other aspects, the UE 104 may not receive the (e.g., first) message indicating the index of the candidate cell within a period / window / duration since / to / from the SRS transmission for uplink timing advance acquisition associated with the candidate cell. This period may be configured for the SRS resource, SRS resource set, and / or candidate cell associated with the SRS transmission. In such a case, the UE 104 may transmit / send another (e.g., second) message to the BS 102 to indicate that timing advance acquisition for the candidate cell failed or was unsuccessful.

[0085] In some cases, the UE 104 may transmit a message indicating timing advance-related information. The UE 104 can determine an uplink timing advance value associated with the candidate cell indicated by the message according to the timing advance-related information. In various aspects, the message can be carried in MAC CE and / or DCI format, among other types of signaling.

[0086] Exemplary Implementation 3: Timing Advance Related Messages Based on Downlink Timing In various configurations, the system and method of the technical solution can determine and / or indicate timing advance-related information associated with a candidate cell based on or according to downlink timing of the candidate cell and at least one other cell. The UE 104 can determine the downlink timing of the cell based on reception of a DL-RS associated with the cell. The UE 104 can determine the timing advance-related information associated with the candidate cell based on reception of a DL-RS associated with the candidate cell and reception of a DL-RS associated with another cell. The at least one other cell can be a cell different from the source cell or the candidate cell (e.g., a second candidate cell).

[0087] In some implementations, the UE 104 may determine a timing advance value associated with the candidate cell based on a difference (e.g., delta) between the downlink timing of the candidate cell and one other cell and / or timing advance-related information associated with the one other cell. For example, the difference in downlink timing of downlink frames for the source cell and the candidate cell may be T rx_diff corresponds to or T rx_diff If the downlink timing of the downlink frame for the source cell is earlier than the downlink timing for the candidate cell, T rx_diff can be positive (e.g., a value). Otherwise, if the downlink timing of the downlink frame from the source cell is slower than the candidate cell, T rx_diff can be negative. The timing advance value associated with the source cell is N TA,0 The UE 104 may determine the timing advance value associated with the candidate cell as, for example, N TA,0 +2×T rx_diff can be determined.

[0088] In another example, the difference in downlink timing of the downlink frames for the source cell and the candidate cell is T rx_diffThe timing advance command associated with the source cell can be T A,0 In this example, the UE 104 may set the timing advance value associated with the candidate cell to N TA,new =N TA,old +N TAC,0 +2×T rx_diff where N TA,old can represent the current TA value of the candidate cell, and N TAC,0 is T A,0 The determination can be made based on the following:

[0089] In some implementations, the UE 104 may receive / obtain / acquire (e.g., from a candidate cell) a message indicating or including a TA assistance value associated with the candidate cell. In response to receiving the message, the UE 104 may determine a timing advance value associated with the candidate cell based on or according to at least one of a downlink timing difference between the candidate cell and one other cell, timing advance-related information associated with the one other cell, and / or the TA assistance value.

[0090] For example, the difference in downlink timing of the downlink frames for the source cell and the candidate cell is T rx_diff and the timing advance value associated with the source cell can be N TA,0 and the TA assistance value is N TA_delta The UE 104 can calculate the N TA,0 +2×T rx_diff +N TA_delta In another example, the timing advance value associated with the candidate cell may be determined according to T rx_diff The timing advance command associated with the source cell can be T A,0 In this example, the UE 104 may set the timing advance value associated with the candidate cell to, for example, N TA,new =NTA,old +N TAC,0 +2×T rx_diff +N TA_delta In various configurations, the TA assistance value may be carried in an RRC message, a MAC CE, and / or a DCI format, among other types of signaling.

[0091] In some implementations, SRS and / or PRACH transmission for timing advance acquisition may be triggered or activated / initiated / performed when / in a situation where the downlink timing difference between the candidate cell and one other cell is greater than (or equal to, in some cases, a threshold value). The UE 104 may, for example, determine the transmission timing of the SRS and / or PRACH transmission using the downlink timing of the corresponding candidate cell and / or one other cell as a reference. In some cases, the UE 104 may determine the transmission timing of the SRS and / or PRACH transmission according to a timing advance value that may be the same as the timing advance value described in connection with exemplary aspect 2 of implementation 2, for example.

[0092] In some implementations, the UE 104 may transmit a message to the BS 102 (e.g., the serving cell) including the downlink timing difference between the candidate cell and one other cell and the index of the candidate cell if the downlink timing difference between the candidate cell and one other cell is greater than a threshold. In various implementations discussed herein, the threshold may be configured / updated / provided for the candidate cell and / or may be predefined according to the configuration of the candidate cell.

[0093] Referring now to FIG. 5, a flow diagram of a method 500 for uplink timing alignment for inter-cell mobility is shown. The method 500 may be implemented using or performed by any of the components detailed above, such as the UE 104 or 204 and the BS 102 or 202, among others. In overview, at operation 702, a wireless communication node may transmit a configuration to a wireless communication device. At operation 704, the wireless communication device may receive a configuration from the wireless communication node. At operation 706, the wireless communication device may transmit a transmission to the wireless communication node. At operation 708, the wireless communication node may receive a transmission from the wireless communication device.

[0094] More particularly, at operation 702, a wireless communication node (e.g., a BS, gNB, or TRP) of a candidate cell for a wireless communication device (e.g., a UE) may send / transmit / provide a configuration associated with the candidate cell to the wireless communication device. The configuration may configure the wireless communication device for TA acquisition during or before a cell switch. At operation 704, the wireless communication device may receive / obtain / obtain the configuration associated with the candidate cell from the wireless communication node.

[0095] At operation 706, the wireless communication device may send a transmission to a wireless communication node in accordance with the configuration. At operation 708, the wireless communication node may receive the transmission sent by the wireless communication device in accordance with the configuration.

[0096] In various configurations, the configuration may include / comprise a random access channel configuration. The transmission may include a physical random access channel (PRACH) transmission. In such a configuration, the wireless communication device may initiate / initiate / perform / perform a random access procedure associated with the candidate cell in accordance with the configuration or in accordance with a message / information from the wireless communication node indicating at least one PRACH transmission parameter for the candidate cell.

[0097] In some implementations, a wireless communication node may receive a message indicating that a random access procedure has been initiated to obtain timing advance (TA) related information of a candidate cell from a wireless communication device. In some cases, at least one of the following may occur: after transmitting the message, the wireless communication device may not detect (e.g., skip, avoid, bypass) a downlink control information (DCI) format associated with scheduling a random access response (RAR) associated with the random access procedure and / or may not receive the RAR; after transmitting the message, the wireless communication device may not detect a DCI format associated with scheduling a physical downlink shared channel (PDSCH) that includes a user equipment (UE) contention resolution identity and / or may not receive the PDSCH that includes the UE contention resolution identity; after transmitting the message, the wireless communication device may not detect a DCI format with cyclic redundancy check (CRC) bits scrambled by a corresponding MsgB radio network temporary identifier (RNTI) and / or may not receive the MsgB; and / or the message may comprise at least one of a cell RNTI (C-RNTI), a random access RNTI (RA-RNTI), an MsgB RNTI, a random access preamble index, and / or a candidate cell index.

[0098] In some implementations, the wireless communication node may transmit a message to the wireless communication device after receiving Msg1, Msg3, and / or MsgA indicating that the random access procedure has finished or completed and / or that the PRACH transmission has been successfully received / acquired. Depending on whether the message is transmitted after receiving at least one of Msg1, Msg, and / or MsgA, at least one of the following may occur: the wireless communication device may not detect a downlink control information (DCI) format associated with scheduling a random access response (RAR) associated with the random access procedure and / or may not receive the RAR; the wireless communication device may not detect a DCI format associated with scheduling a physical downlink shared channel (PDSCH) that includes a user equipment (UE) contention resolution identity and / or may not receive the PDSCH that includes the UE contention resolution identity; the wireless communication device may not detect a DCI format with cyclic redundancy check (CRC) bits scrambled by a corresponding MsgB radio network temporary identifier (RNTI) and / or may not receive the MsgB; and / or the message may be transmitted after receiving at least one of the Cell RNTI (C-RNTI), the Random Access RNTI (RA-RNTI), and / or the MsgB. The DCI format may include a DCI format with CRC bits scrambled by the RNTI, and / or a DCI format with an indication field with bits set to a particular value, and / or a particular indication field, and / or a DCI format with particular Medium Access Control Control Element (MAC CE) signaling. In response to these communications between the wireless communication node and the wireless communication device (e.g., in the case of a partial random access procedure), the system and method may reduce / minimize cell switch latency since information is communicated before or during the cell switch.

[0099] In some implementations, at least one of the following: the wireless communication node may send a random access response (RAR) message to the wireless communication device indicating terminating or successfully completing the random access procedure, wherein the RAR message may indicate at least one of a physical cell index (PCI), a candidate cell index, a flag indicating whether to complete or terminate the random access procedure, and / or timing advance (TA) related information; the wireless communication node may send a configuration to the wireless communication device to enable or disable the wireless communication device from performing a partial random access procedure, wherein when performing the partial random access procedure, one or more steps of any of the implementations or features described above may be performed, and / or when performing the partial random access procedure is disabled, the random access may be performed according to a two-step type random access or a four-step type random access procedure; the wireless communication node may send one or more RAR messages to the wireless communication device. Each of the one or more RAR messages may indicate TA-related information associated with a corresponding candidate cell, and the wireless communication device may determine (or calculate) an uplink transmission timing associated with the corresponding candidate cell indicated by the cell switch message based at least on or at least in accordance with the TA-related information associated with the corresponding candidate cell, and / or the wireless communication node may transmit a cell switch message to the wireless communication device, the cell switch message indicating a cell index and / or at least one of the TA-related information associated with the cell index.

[0100] In some implementations, at least one of the following determinations can be performed taking into account the cell index: for transmitting a random access preamble, the wireless communication node can determine a random access network temporary identifier (RA-RNTI) associated with the PRACH occasion on which the random access preamble is transmitted as a function of the index (cell_id) of the candidate cell associated with the transmission of the random access preamble; and / or for transmitting an MsgA, the wireless communication node can determine a MSGB network temporary identifier (RNTI) associated with the PRACH occasion on which the random access preamble is transmitted as a function of cell_id and cell_total, where cell_total can be or correspond to the maximum number of candidate cells supported according to the capabilities of the wireless communication device, and / or the number of configured candidate cells, and / or a defined / fixed / configured value. cell_id can be an integer value greater than or equal to 0 and / or less than or equal to the value of cell_total. The defined value is or can be configured to be one of the following: {1,2,3,4,5,6,7} / {1,2,3,4,5,6,7}.

[0101] In some implementations, a wireless communication node may transmit a configuration to a wireless communication device to configure the wireless communication device with a timing advance (TA)-related timer (e.g., for contention-based random access (CBRA) for TA acquisition during cell switching) for a candidate cell. In this case, upon expiration of the timing advance-related timer, the wireless communication device may initiate a random access procedure associated with the candidate cell.

[0102] In various configurations, at least one of the following may be true: the configuration may include a configuration of one or more sounding reference signal (SRS) resources and / or SRS resource sets associated with timing advance (TA) acquisition; the transmission may include an SRS transmission; the SRS transmission may be for uplink timing advance acquisition for the candidate cell; and / or the one or more SRS resources and / or SRS resource sets may be associated with the candidate cell and / or at least one of the candidate cell's downlink reference signals (DL-RS).

[0103] In some implementations, the wireless communication node may receive an SRS transmission from a wireless communication device, and at least one of the following: the SRS transmission may correspond to SRS activation or deactivation medium access control element (MAC CE) signaling or downlink control information (DCI) signaling; a field within the SRS activation or deactivation MAC CE signaling or DCI signaling may indicate that the SRS transmission is activated or triggered for timing advance acquisition of the candidate cell; and / or the SRS transmission may be associated with the candidate cell.

[0104] In some implementations, the wireless communication device may determine uplink transmission timing of an SRS transmission associated with timing advance acquisition for the candidate cell based at least on or at least according to a timing advance value and downlink timing, where the timing advance value may include (i) 0, (ii) a timing advance value associated with the source cell, (3) a timing advance value associated with a cell different from the candidate cell, and / or (4) a timing advance value associated with the candidate cell, and / or the downlink timing may include (i) downlink timing associated with the source cell, (ii) downlink timing associated with the candidate cell, and / or (iii) downlink timing associated with a cell different from the candidate cell.

[0105] In some aspects, at least one of the following occurs: after an SRS transmission for uplink timing advance acquisition, the wireless communication device may receive a message indicating an index of the candidate cell and cancel the activation / initiating or triggered transmission of the SRS for uplink timing advance acquisition associated with the candidate cell; or the wireless communication device may not receive a message (e.g., a first message) indicating an index of the candidate cell within a time period associated with an SRS transmission for uplink timing advance acquisition associated with the candidate cell, the time period may be configured for an SRS resource, an SRS resource set, and / or the candidate cell associated with the SRS transmission, and the wireless communication device may transmit another message (e.g., a second message) to the wireless communication node indicating that the uplink timing advance acquisition for the candidate cell has failed (e.g., was not successful).

[0106] While various embodiments of the present solution have been described above, it should be understood that they are presented by way of example only, and not by way of limitation. Similarly, various diagrams may depict example architectures or configurations provided to enable those skilled in the art to understand example features and functionality of the present solution. However, such skilled artisans will understand that the present solution is not limited to the illustrated example architectures or configurations, but can be implemented using various alternative architectures and configurations. In addition, as will be understood by those skilled in the art, one or more features of one embodiment can also be combined with one or more features of another embodiment described herein. Thus, the breadth and scope of the present disclosure should not be limited by any of the example embodiments described above.

[0107] It will also be understood that any reference to elements herein using designations such as "first," "second," etc., generally does not limit the number or order of those elements. Rather, these designations may be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to a first and a second element does not imply that only two elements can be used, nor that the first element must precede the second element in any way.

[0108] Additionally, those skilled in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, and symbols that may be referred to in the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0109] Those skilled in the art will further appreciate that any of the various illustrative logical blocks, modules, processors, means, circuits, methods, and functions described in connection with the aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementations, analog implementations, or a combination of the two), firmware, various forms of programs or design code incorporating instructions (which may be referred to herein for convenience as “software” or “software modules”), or any combination of these techniques. To clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these techniques, depends on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in various ways for each particular application, and such implementation decisions do not cause a departure from the scope of the present disclosure.

[0110] Furthermore, those skilled in the art will understand that the various example logic blocks, modules, devices, components, and circuits described herein can be implemented within or performed by an integrated circuit (IC), which may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logic blocks, modules, and circuits may further include an antenna and / or transceiver for communicating with various components within a network or device. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration for performing the functions described herein.

[0111] If implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media, including any medium that can transfer a computer program or code from one place to another. A storage medium can be any available medium that can be accessed 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 desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0112] As used herein, the term "module" refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, while for purposes of discussion, various modules are described as individual modules, those skilled in the art will appreciate that two or more modules may be combined to form a single module that performs associated functions according to embodiments of the present solution.

[0113] Additionally, memory or other storage, as well as communication components, may be used in embodiments of the solution. It will be appreciated that, for clarity, the above description describes embodiments of the solution with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements, or domains may be used without detracting from the solution. For example, functionality illustrated as being performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. References to specific functional units therefore do not refer to a strict logical or physical structure or organization, but merely to suitable means for providing the described functionality.

[0114] Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as set forth in the following claims.

Claims

1. 1. A method comprising: a wireless communication node of a candidate cell for a wireless communication device transmitting to said wireless communication device a configuration associated with said candidate cell; receiving, by the wireless communication node, a transmission sent by the wireless communication device in accordance with the configuration; A method comprising:

2. the configuration comprises a random access channel configuration; 10. The method of claim 1, wherein the transmission comprises a Physical Random Access Channel (PRACH) transmission.

3. 3. The method of claim 2, wherein the wireless communication device initiates a random access procedure associated with the candidate cell in accordance with the configuration or in accordance with a message from the wireless communication node indicating at least one PRACH transmission parameter for the candidate cell.

4. 3. The method of claim 2, comprising the wireless communication node receiving, from the wireless communication device, a message indicating that a random access procedure has been initiated to obtain Timing Advance (TA) related information of the candidate cell.

5. after transmitting the message, the wireless communication device does not detect a Downlink Control Information (DCI) format associated with scheduling of a Random Access Response (RAR) associated with the random access procedure or does not receive the RAR; after transmitting the message, the wireless communication device does not detect a DCI format associated with scheduling of a physical downlink shared channel (PDSCH) that includes a user equipment (UE) contention resolution identity or does not receive the PDSCH that includes the UE contention resolution identity; after transmitting the message, the wireless communication device does not detect a DCI format or receive an MsgB with cyclic redundancy check (CRC) bits scrambled by a corresponding MsgB radio network temporary identifier (RNTI); or the message comprises at least one of a Cell RNTI (C-RNTI), a Random Access RNTI (RA-RNTI), a MsgB RNTI, a Random Access Preamble Index, or a Candidate Cell Index. The method of claim 4, wherein the at least one of

6. the wireless communication node transmitting to the wireless communication device a message indicating that it has finished or completed a random access procedure or successfully received a PRACH transmission after receiving Msg1, Msg3, or MsgA. Including, the wireless communication device does not detect a Downlink Control Information (DCI) format associated with scheduling of a Random Access Response (RAR) associated with the random access procedure or does not receive the RAR; the wireless communication device does not detect a DCI format associated with scheduling of a physical downlink shared channel (PDSCH) that includes a user equipment (UE) contention resolution identity or does not receive a PDSCH that includes the UE contention resolution identity; the wireless communication device does not detect a DCI format or does not receive an MsgB with cyclic redundancy check (CRC) bits scrambled by a corresponding MsgB radio network temporary identifier (RNTI); or The message comprises a DCI format having CRC bits scrambled by a Cell RNTI (C-RNTI), a Random Access RNTI (RA-RNTI), or an MsgB RNTI, or an indication field having bits set to a specific value, or a specific indication field, or a DCI format having specific Medium Access Control Control Element (MAC CE) signaling. The method of claim 2, wherein the at least one of

7. transmitting, by the wireless communication node, to the wireless communication device, a random access response (RAR) message indicating terminating or successfully completing a random access procedure, wherein the RAR message indicates at least one of a physical cell index (PCI), a candidate cell index, a flag indicating whether to complete or terminate the random access procedure, or timing advance (TA) related information; transmitting, by the wireless communication node, to the wireless communication device, a configuration for enabling or disabling the wireless communication device from performing a partial random access procedure, wherein when performing the partial random access procedure is enabled, one or more steps of any one of claims 1 to 7 are performed, and when performing the partial random access procedure is disabled, random access is performed according to a two-step type random access or a four-step type random access procedure; the wireless communication node transmitting one or more RAR messages to the wireless communication device, each of the one or more RAR messages indicating TA-related information associated with a corresponding candidate cell, and the wireless communication device determining, based at least on the TA-related information associated with the corresponding candidate cell, an uplink transmission timing associated with the corresponding candidate cell indicated by a cell switch message; or transmitting, by the wireless communications node, to the wireless communications device, a cell switch message indicating at least one of a cell index or TA-related information associated with the cell index. The method of claim 2 , comprising at least one of:

8. the wireless communication node for transmission of a random access preamble determining a Random Access Network Temporary Identifier (RA-RNTI) associated with a PRACH occasion on which the random access preamble is transmitted as a function of an index (cell_id) of the candidate cell associated with the transmission of the random access preamble; or the wireless communication node for transmitting MsgA determines an MSGB Network Temporary Identifier (RNTI) associated with a PRACH occasion on which the random access preamble is transmitted as a function of the cell_id and cell_total, cell_total is the maximum number of candidate cells supported according to the capabilities of said wireless communication device, or the number of configured candidate cells, or a defined value; cell_id is an integer value greater than or equal to 0 and less than or equal to the value of cell_total, and said defined value is one from {1, 2, 3, 4, 5, 6, 7}. The method of claim 2 , comprising at least one of:

9. the wireless communication node transmitting to the wireless communication device a configuration for configuring the wireless communication device with a Timing Advance (TA) related timer for the candidate cell. Including, 3. The method of claim 2, wherein upon expiration of the timing advance related timer, the wireless communication device initiates a random access procedure associated with the candidate cell.

10. the configuration comprising a configuration of one or more sounding reference signal (SRS) resources or SRS resource sets associated with timing advance (TA) acquisition; the transmission comprises an SRS transmission; the SRS transmission is for uplink timing advance acquisition for the candidate cell; or The one or more SRS resources or SRS resource sets are associated with at least one of the candidate cell or a downlink reference signal (DL-RS) of the candidate cell. The method of claim 1 , wherein the at least one of

11. receiving, by the wireless communication node, the SRS transmission from the wireless communication device; Including, the SRS transmission corresponds to SRS activation or deactivation medium access control element (MAC CE) signaling or downlink control information (DCI) signaling; a field in the SRS activation or deactivation MAC CE signaling or the DCI signaling indicates that the SRS transmission is activated or triggered for timing advance acquisition of the candidate cell; or The SRS transmission is associated with the candidate cell. The method of claim 10, wherein the at least one of

12. the wireless communication device determines an uplink transmission timing of the SRS transmission associated with timing advance acquisition for the candidate cell based at least on a timing advance value and a downlink timing; the timing advance value comprises (i) 0, (ii) a timing advance value associated with a source cell, (3) a timing advance value associated with a cell different from the candidate cell, or (4) a timing advance value associated with the candidate cell; or the downlink timing comprises (i) downlink timing associated with the source cell, (ii) downlink timing associated with the candidate cell, or (iii) downlink timing associated with a cell different from the candidate cell; The method of claim 10, wherein the at least one of

13. receiving, by the wireless communication device after the SRS transmission for uplink timing advance acquisition, a message indicating an index of the candidate cell, and canceling an activated or triggered transmission of an SRS for uplink timing advance acquisition associated with the candidate cell; or the wireless communication device does not receive the message indicating the index of the candidate cell within a time period associated with the SRS transmission for uplink timing advance acquisition associated with the candidate cell, the time period being configured for an SRS resource, an SRS resource set, or the candidate cell associated with the SRS transmission; transmitting another message to the wireless communication node indicating that the uplink timing advance acquisition for the candidate cell was unsuccessful. The method of claim 10, wherein the at least one of

14. receiving, by a wireless communication device, a configuration associated with a candidate cell from a wireless communication node of said candidate cell; the wireless communication device sending a transmission to the wireless communication node in accordance with the configuration; A method comprising:

15. 15. A non-transitory computer readable medium storing instructions that, when executed by at least one processor, cause the at least one processor to perform the method of any one of claims 1 to 14.

16. An apparatus comprising at least one processor configured to perform the method of any one of claims 1 to 14.

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