System and method for uplink timing alignment for inter-cell mobility

Abstract

Systems, methods, apparatus, or computer readable media for uplink timing alignment for inter-cell mobility are presented. A wireless communication node of a candidate cell of a wireless communication device may send a configuration associated with the candidate cell to the wireless communication device. The wireless communication node may receive a transmission sent by the wireless communication device according to the configuration.

Description

Technical Field

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

[0002] The Third Generation Partnership Project (3GPP), a standards organization, is currently developing a new radio interface standard called 5G New Radio (5G NR), as well as a standard for the Next Generation Packet Core Network (NG-CN or NGC). 5G NR will consist of three main components: the 5G Access Network (5G-AN), the 5G Core Network (5G GC), and the User Equipment (UE). To facilitate the implementation of diverse data services and requirements, the various elements of the 5GC (also known as network functions) have been simplified, with some being software-based so that they can be adjusted as needed. Summary of the Invention

[0003] The example embodiments disclosed herein are intended to address one or more problems in the prior art and to provide additional features, which will become apparent when reference is made to the following detailed description in conjunction with the accompanying drawings. According to various embodiments, example systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are provided as examples only and are not limiting, and those skilled in the art who read this disclosure will understand that various modifications may be made to the disclosed embodiments while still within the scope of the present invention.

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

[0005] In some implementations, the configuration may include configuration of a random access channel. The transmission may include a physical random access channel (PRACH) transmission. In some implementations, the wireless communication device may initiate / perform a random access procedure associated with a candidate cell based on the configuration or based on 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 a random access procedure for timing advance (TA) acquisition of a candidate cell. When the maximum number of PRACH transmissions associated with the random access procedure is reached, the random access procedure may be considered unsuccessful (e.g., failed).

[0007] In some implementations, the wireless communication node may receive a message indicating that a random access procedure for acquiring timing advance TA-related information of the candidate cell is initiated. In some implementations, at least one of the following situations exists: after sending the message, the wireless communication device may not detect (e.g., avoid / skip / ignore detection) a downlink control information (DCI) format associated with a random access response (RAR) scheduling, or may not receive a RAR; after sending the message, the wireless communication device may not detect a DCI format associated with a physical downlink shared channel (PDSCH) scheduling including a user equipment (UE) contention resolution identifier, or may not receive a PDSCH including a UE contention resolution identifier; after sending the message, the wireless communication device may not detect a DCI format with a cyclic redundancy check (CRC) bit scrambled by a corresponding message B (MsgB) radio network temporary identifier (RNTI) (i.e., MsgB-RNTI), or may not receive an MsgB; and / or the message may include at least one of the following: a cell RNTI (Cell RNTI); RNTI, C-RNTI), Random Access RNTI (RA-RNTI), MsgB-RNTI, random access preamble index and / or candidate cell index.

[0008] In some implementations, a wireless communication node may receive a message 1 (Message 1, Msg1), a message 3 (Message 3, Msg3), or a message A (Message A, MsgA), after receiving the random access procedure, sends a message to the wireless communication device indicating the termination or completion of the random access procedure or the successful reception of the PRACH transmission, wherein at least one of the following situations exists: the wireless communication device may not detect the downlink control information (DCI) format related to the random access response RAR scheduling related to the random access procedure, or may not receive the RAR; the wireless communication device may not detect the DCI format related to the physical downlink shared channel PDSCH scheduling containing the user equipment UE contention resolution identifier, or may not receive the PDSCH containing the UE contention resolution identifier; the wireless communication device may not detect the DCI format with CRC bits scrambled by the corresponding message B radio network temporary identifier MsgB-RNTI, or may not receive the MsgB; and / or the message may include a DCI format with CRC bits scrambled by the C-RNTI, RA-RNTI or MsgB-RNTI, or a DCI format with an indication field and its bits set to a specific value, or a DCI format with a specific indication field, or a specific Medium Access Control Control Element (MAC CE) signaling.

[0009] 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 termination or successful completion of the random access procedure, wherein the RAR message may indicate at least one of the following: a physical cell identifier (Physical Cell Identifier); 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 the partial random access procedure is enabled, one or more steps / procedures / features described herein are performed, and / or when the partial random access procedure is disabled, random access may be performed according to a two-step random access or a four-step random access procedure; the wireless communication node may send one or more RAR messages to the wireless communication device, wherein 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, based at least on the TA-related information associated with the corresponding candidate cell, an uplink transmission time associated with the corresponding candidate cell indicated by a cell handover message; and / or the wireless communication node may send a cell handover message to the wireless communication device, wherein the cell handover message indicates at least one of the following: a cell index, and / or TA-related information associated with the cell index.

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

[0011] In some implementations, the wireless communication node may send a configuration to the wireless communication device to configure a timing advance TA timer associated with a candidate cell. When the timing advance related timer expires, the wireless communication device may initiate a random access process associated with the candidate cell.

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

[0013] In some implementations, a wireless communication node may receive an SRS transmission from a wireless communication device, wherein at least one of the following situations exists: the SRS transmission may correspond to SRS activation or deactivation media access control element MAC CE signaling or downlink control information DCI signaling; a field in 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 a candidate cell; and / or the SRS transmission may be associated with a candidate cell.

[0014] In some implementations, the wireless communication device may determine an uplink transmission time for an SRS transmission associated with timing advance acquisition of a candidate cell based at least on a timing advance value and downlink timing, wherein at least one of: the timing advance value may include: (i) zero, (ii) a timing advance value associated with a source cell, (iii) a timing advance value associated with a cell different from the candidate cell, and / or (iv) 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.

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

[0016] At least one aspect relates to a system, method, apparatus, or computer-readable medium. A wireless communication device (e.g., a user equipment (UE)) may receive a configuration related to a candidate cell from a wireless communication node (e.g., a base station (BS), gNB, or a transmit / receive point (TRP)). The wireless communication device may send a transmission to the wireless communication node based on the configuration.

[0017] The systems and methods described herein include a novel method for uplink timing adjustment for inter-cell mobility. Specifically, the systems and methods described herein discuss a novel solution in which a UE (e.g., a wireless communication device) obtains / receives a timing advance value for at least one candidate cell, such as in a case / instance / scenario in which the UE requests a cell handover. For example, the systems and methods of the present technical solution may provide a technique for performing a partial random access procedure to obtain a timing advance value, propose a method / process / step / feature based on sounding reference signal (SRS) transmission to obtain a timing advance value, and / or propose a method based on a downlink timing difference to obtain a timing advance value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various example embodiments of the present solution are described in detail below with reference to the following figures. The figures are for illustrative purposes only and depict only example embodiments of the present solution to aid the reader's understanding of the present solution. Therefore, the figures should not be construed as limiting the breadth, scope, or applicability of the present solution. It should be noted that for clarity and ease of illustration, the figures are not necessarily drawn to scale.

[0019] Figure 1 An example cellular communication network is shown, in which the techniques disclosed herein may be implemented, according to an embodiment of the present invention;

[0020] Figure 2 A block diagram illustrating an example base station and user equipment according to some embodiments of the present invention is shown;

[0021] Figure 3 shows a deployment scenario of inter-cell mobility according to an exemplary embodiment;

[0022] Figure 4 A block diagram illustrating timing advance management for inter-cell mobility according to an exemplary embodiment; and

[0023] Figure 5 A flow chart of an uplink timing alignment method for inter-cell mobility according to an exemplary embodiment is shown. DETAILED DESCRIPTION

[0024] Various example embodiments of the present solution will be described below with reference to the accompanying drawings to enable a person of ordinary skill in the art to implement and use the present solution. It will be apparent to a person of ordinary skill in the art after reading this disclosure that various changes or modifications may be made to the examples described herein without departing from the scope of the invention. Therefore, the present solution is not limited to the example embodiments and applications described and illustrated herein. In addition, the specific order or hierarchy of steps in the methods disclosed herein are merely example methods. Based on design preferences, the specific order or hierarchy of steps of the disclosed methods or processes may be rearranged without departing from the scope of the present solution. Therefore, it will be understood by a person of ordinary skill in the art that the methods and techniques disclosed herein present various steps or actions in an example order, and unless expressly stated otherwise, the present solution is not limited to the specific order or hierarchy presented.

[0025] 1. Mobile Communication Technology and Environment

[0026] Figure 1 An example wireless communication network and / or system 100 is shown in accordance with an embodiment of the present invention, in which the techniques disclosed herein may be implemented. In the following discussion, the wireless communication network 100 may be any wireless network, such as a cellular network or a Narrow Band Internet of Things (NB-IoT) network, and is referred to herein as "network 100." Such an example network 100 includes a base station 102 (hereinafter referred to as "BS 102"; also referred to as a wireless communication node) and a user equipment 104 (hereinafter referred to as "UE 104"; also referred to as a wireless communication device), which may communicate with each other via a communication link 110 (e.g., a wireless communication channel), and a set of cells 126, 130, 132, 134, 136, 138, and 140 covering a geographic area 101. Figure 1 1 , BS 102 and UE 104 are located within the respective geographic boundaries of cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 contains at least one base station operating within its allocated bandwidth to provide adequate wireless coverage for its intended users.

[0027] For example, BS 102 can operate within the allocated channel transmission bandwidth to provide sufficient coverage for UE 104. BS 102 and UE 104 can communicate via downlink radio frames 118 and uplink radio frames 124, respectively. Each radio frame 118 / 124 can be further divided into subframes 120 / 127, each of which can contain data symbols 122 / 128. In the present invention, BS 102 and UE 104 are described herein as non-limiting examples of "communication nodes," which can generally perform the methods disclosed herein. According to various embodiments of the present solution, such communication nodes can support wireless and / or wired communications.

[0028] Figure 2 A block diagram of a wireless communication system 200 is shown according to some embodiments of the present solution, the system being configured to transmit and receive wireless communication signals (e.g., Orthogonal Frequency Division Multiplexing (OFDM) / Orthogonal Frequency Division Multiple Access (OFDMA) signals). The system 200 may include components and elements configured to support known or conventional operating functions, which need not be described in detail herein. In an exemplary embodiment, the system 200 may be used in a wireless communication environment (e.g., Figure 1 The wireless communication environment 100 is shown to communicate (eg, transmit and receive) data symbols, as described above.

[0029] System 200 generally includes a base station 202 (hereinafter referred to as "BS 202") and a user equipment 204 (hereinafter referred to as "UE 204"). BS 202 includes a BS 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. UE 204 includes a UE 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. BS 202 communicates with UE 204 via a communication channel 250, which can be any wireless channel described herein or other medium suitable for data transmission.

[0030] It should be understood by those skilled in the art that the system 200 may further include Figure 2Any number of modules other than the modules shown. Those skilled in the art will appreciate that the various exemplary blocks, modules, circuits, and processing logic described in conjunction with the embodiments disclosed herein can be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. In order to clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, various exemplary components, blocks, modules, circuits, and steps are generally described in terms of their functions. Whether these functions are implemented in hardware, firmware, or software depends on the specific application and the design constraints imposed on the entire system. Those familiar with the concepts described herein can implement these functions in an appropriate manner for each specific application, but these implementation decisions should not be interpreted as limiting the scope of the present invention.

[0031] According to some embodiments, the UE transceiver 230 may be referred to herein as an uplink (UL) transceiver 230 and includes a radio frequency (RF) transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 232. A duplex switch (not shown) may couple the uplink transmitter or receiver to the uplink antenna in a time-division duplex manner. Similarly, according to some embodiments, the BS transceiver 210 may be referred to herein as a downlink (DL) transceiver 210 and includes an RF transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 212. The downlink duplex switch may couple the downlink transmitter or receiver to the downlink antenna 212 in a time-division duplex manner. The operation of the two transceiver modules 210 and 230 may be coordinated in time such that the uplink receiver circuit is coupled to the uplink antenna 232 to receive transmissions on the wireless transmission link 250 while the downlink transmitter is coupled to the downlink antenna 212. Instead, the operations of the two transceivers 210 and 230 can be coordinated in time such that the downlink receiver is coupled to the downlink antenna 212 to receive transmissions on the wireless transmission link 250 while the uplink transmitter is coupled to the uplink antenna 232. In some embodiments, there is tight time synchronization between duplex direction changes, and guard times are very short.

[0032] The UE transceiver 230 and the base station transceiver 210 are configured to communicate via a wireless data communication link 250 and to work in conjunction with a suitably configured radio frequency (RF) antenna device 212 / 232 that is capable of supporting a specific wireless communication protocol and modulation scheme. In some exemplary embodiments, the UE transceiver 230 and the base station transceiver 210 are configured to support industry standards such as LTE and emerging 5G standards. However, it should be understood that the present invention is not necessarily limited to the application of specific standards and related protocols. Instead, the UE transceiver 230 and the base station transceiver 210 can be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0033] According to various embodiments, BS 202 may be an evolved Node B (eNB), a serving eNB, a target eNB, a femto base station, or a pico base station. In certain embodiments, UE 204 may be embodied as various types of user equipment, such as a mobile phone, a smartphone, a personal digital assistant, a tablet, a laptop computer, a wearable computing device, or the like. Processor modules 214 and 236 may be implemented 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. In this manner, the processor may be implemented as a microprocessor, a controller, a microcontroller, a state machine, or the like. The processor may also be implemented as a combination of computing devices, such as a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors and a digital signal processor core, or any other such configuration.

[0034] Furthermore, the steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be directly embodied in hardware, firmware, or software modules executed by the processor modules 214 and 236, respectively, or any practical combination thereof. The memory modules 216 and 234 may be implemented as random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In this regard, the memory modules 216 and 234 may be coupled to the processor modules 214 and 236, respectively, so that the processor modules 210 and 230 can read information from and write information to the memory modules 216 and 234, respectively. The memory modules 216 and 234 may also be integrated into their respective processor modules 214 and 236. In some embodiments, the memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information while the processor modules 214 and 236 execute instructions, respectively. The memory modules 216 and 234 may also each include a non-volatile memory for storing instructions to be executed by the processor modules 210 and 230, respectively.

[0035] The network communication module 218 generally represents the hardware, software, firmware, processing logic, and / or other components of the base station 202 that enable bidirectional communication between the base station transceiver 210 and other network components and communication nodes configured to communicate with the base station 202. For example, the network communication module 218 may be configured to support Internet or Worldwide Interoperability for Microwave Access (WiMAX) traffic. In a typical deployment (but not limited to), the network communication module 218 provides an 802.3 Ethernet interface to enable the base station transceiver 210 to communicate with a conventional Ethernet-based computer network. Thus, the network communication module 218 may include a physical interface for connecting to a computer network (e.g., a Mobile Switching Center (MSC)). As used herein, the terms "configured to," "configured for," and variations thereof, when describing a particular operation or function, refer to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted, and / or arranged to perform the specified operation or function.

[0036] The Open Systems Interconnection (OSI) model (herein referred to as the "OSI model") is a conceptual and logical layout that defines network communications used by systems (e.g., wireless communication devices, wireless communication nodes) that interconnect and communicate with other systems. The model is divided into seven subcomponents, or layers, each representing a conceptual set of services provided to upper and lower layers. The OSI model also defines a logical network and effectively describes the transmission of computer data packets using different layer protocols. The OSI model is also referred to as the 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 media 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 may be other layers.

[0037] II. System and Method for Uplink Timing Alignment for Inter-Cell Mobility

[0038] In some systems, UE mobility (e.g., mobility of UE 104) may refer to switching from one cell (e.g., NR cell) to another cell, or be defined as such switching. The switching may be performed based on or according to measurements of synchronization signals associated with different cells and / or transmit / receive points (TRPs). For certain types of mobility (e.g., layer 3-based mobility) or systems, downlink and uplink synchronization (e.g., DL / UL synchronization) may be performed after or subsequently after UE 104 switches to another cell, resulting in a relatively large latency in cell switching. For certain other types of mobility (e.g., layer 1 and / or layer 2-based mobility), when UE 104 is configured with one or more candidate cells, UE 104 may perform downlink and / or uplink synchronization for the candidate cells prior to cell switching. In this case, downlink and / or uplink synchronization may be established before the UE receives a cell switching command message, thereby reducing / minimizing the latency in cell switching.

[0039] Uplink synchronization can ensure or cause the transmission arrival times from multiple user equipments UE 104 to fall within an acceptable / satisfactory range, and / or ensure that demodulation on the network side (e.g., base station BS side) can be performed reliably. Uplink synchronization can be based on, in accordance with, or dependent on an indication message / signal from BS102 (e.g., network) and / or measurements on the UE side. The indication message can be determined / obtained / acquired / identified on the BS side based on uplink channels / signals (e.g., physical random access channel PRACH and / or sounding reference signal SRS) and other types of signals from UE 104. Measurements on the UE side can be based on the reception time of the downlink signal / channel. When uplink synchronization of one or more candidate cells is to be performed, it may be desirable (e.g., by UE 104) to obtain a timing advance value associated with each candidate cell, for example, before or during cell switching to reduce / minimize the delay or waiting time of cell switching.

[0040] See also Figure 3, showing a deployment scenario 300 for inter-cell mobility. Downlink and / or uplink synchronization can be one of the steps / processes / flows to ensure reliable wireless communication in various wireless systems, for example, ensuring reliable communication between at least one user equipment UE104 and at least one base station BS102. In some scenarios, downlink synchronization can be achieved / initiated by receiving / obtaining / receiving a primary synchronization signal (PSS) and / or a secondary synchronization signal (SSS), or in response to receiving / obtaining / receiving a PSS and / or SSS. Uplink synchronization can be achieved by a random access procedure and / or uplink timing alignment maintenance, or in response to a random access procedure and / or uplink timing alignment maintenance. Uplink timing alignment maintenance can be based on a timing advance command (TAC) sent / issued by the base station 102.

[0041] like Figure 3 As shown, when UE 104 is communicating with a current serving cell (e.g., a source cell or a cell currently connected to or serving UE 104), UE 104 may be configured for multiple candidate cells. As the UE becomes more mobile (e.g., as UE 104 moves), UE 104 may desire or be forced to switch from the source cell to a candidate cell. In this case, UE 104 may perform / initiate / perform downlink and / or uplink synchronization of at least one candidate cell.

[0042] For certain user equipment UEs 104, these specific UEs 104 may determine one or more timing advance values ​​based on the number of time alignment groups (TAGs). In a carrier aggregation scenario, the base station BS102 may configure / set one or more TAGs to indicate at least one timing advance command (TAC) for one or more serving cells. Each TAG may include / contain one or more serving cells, or be configured for one or more serving cells. The BS102 may send at least one TAC associated with at least one TAG to the UE 104. The UE 104 may apply / activate / execute the TAC to determine / identify the timing advance of each serving cell in the TAG or associated with the TAG.

[0043] 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 media access control element MAC CE (e.g., a TAC included in or provided via a MAC CE), the UE 104 may update / adjust / configure the timing advance value based on the TAC MAC CE and / or the current timing advance value.

[0044] In various aspects discussed herein, the term "source cell" may refer to, correspond to, or 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 term "cell index," "source cell index," or "candidate cell index" may be expressed as a serving cell index, a physical cell identifier, or a candidate cell index, etc. The term "source cell" or "candidate cell" may include / contain, describe, or refer to at least one of "one or more reference signal information groups," "reference signal resource sets," "physical uplink control channel (PUCCH) resource sets," "antenna port groups," "physical cell identifiers PCIs," "transmitting and receiving point TRP related information," "control resource set (CORESET) pool index," TAGs, "UE capability values," and / or "UE capability sets." The term "MsgB" may include or refer to an absolute timing advance command MAC CE. The term "uplink signal" may include or correspond 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. The term "PRACH transmission" may refer to Msg1 transmission, MsgA transmission and / or random access preamble transmission. The term "uplink transmission" may refer to or correspond to the transmission timing of an uplink signal, a repetition of an uplink signal or the uplink signal itself. The term "downlink reference signal DL-RS" may include, refer to or correspond to a channel state information reference signal (CSI-RS) and / or a synchronization signal block (SSB). The term "timing advance related information" may include / contain at least one of the following: a cell index, a time alignment group TAG index, a timing advance command, a timing advance offset and / or a timing advance offset command.

[0045] In various configurations, the cell index can be a serving cell index, a physical cell identifier, and / or a candidate cell index. A timing advance command can be carried in a MAC RAR and / or a TAC MAC CE to indicate, for example, a timing advance adjustment value. A timing advance offset can be configured for a serving cell to adjust uplink transmission time. A timing advance offset command can be used 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.

[0046] A series or sequence of methods may be considered to obtain / acquire the uplink timing advance value of the candidate cell in the following aspects: methods / aspects / methods / configurations based on a random access procedure, based on SRS transmission, and / or based on a downlink timing difference. In certain configurations, in a configuration based on a random access procedure, the user equipment UE 104 may initiate / start a random access procedure related to the candidate cell to obtain the timing advance. The base station BS102 (e.g., the network of the candidate cell) may determine the timing advance-related information based on a physical random access channel PRACH transmission from the UE 104. The BS102 may send a message / signal / information to the UE 104. The message may be a MsgB, Msg2, MAC RAR, and / or MAC CE indicating the completion of the random access procedure. The UE 104 may determine the timing advance value or decide whether to complete the random access procedure based on the message from the BS102.

[0047] In certain configurations, in a configuration based on SRS transmission, UE 104 may be configured with one or more SRS resources. In this case, UE 104 may transmit an SRS for uplink timing acquisition of a candidate cell. Upon receiving the SRS, BS 102 may determine timing advance-related information based on the SRS transmission from UE 104. BS 102 may send a message to UE 104, which may be in the form of a TAC MAC CE or MAC CE / DCI format, indicating the cancellation / termination of SRS transmission for uplink timing advance acquisition. UE 104 may determine the timing advance value or decide to cancel SRS transmission based on the message from BS 102.

[0048] In certain configurations, in a configuration based on downlink timing difference, user equipment UE 104 may receive one or more downlink reference signals associated with at least one cell. Upon receiving the downlink reference signals, UE 104 may determine the downlink timing of the cell. UE 104 may determine a difference between the downlink timing of a first cell and a second cell. 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. UE 104 may receive a message (e.g., from base station 102) indicating timing advance adjustment information. Upon receiving the message, UE 104 may determine to adjust the timing advance value based on the message.

[0049] In various implementations, the UE 104 may be configured with one or more candidate cells (e.g., communicating with one or more BSs 102 associated with different candidate cells). In this case, the UE 104 may perform uplink time alignment for at least one of the one or more candidate cells. The UE 104 may send an uplink transmission associated with a first cell and adjust / change / update the transmission time of the uplink transmission based on a first timing advance-related message. When the UE 104 receives a cell handover message indicating a second cell from the corresponding BS 102, the UE 104 may send an uplink transmission associated with the second cell and adjust the transmission time of the uplink transmission based on a second timing advance-related message. In this case, the first cell may be associated with or refer to a source cell, and the second cell may be associated with or refer to one of the candidate cells. The second timing advance-related message may be based on the present invention (e.g., in combination with Figure 4 ) is determined / identified by at least one of the methods / features / implementations described in ).

[0050] See also Figure 4 , which shows a block diagram (400) of timing advance management for inter-cell mobility. As shown, before the UE 104 receives a cell handover command / indication / message, the transmission time of the uplink transmission may be determined by or based on a timing advance value obtained for a source cell (e.g., a cell currently serving the UE 104). The UE 104 may obtain / obtain / receive multiple timing advance values ​​for multiple candidate cells (e.g., potential cells for cell handover). In response to the UE 104 receiving the cell handover command, or upon receiving the command, the UE 104 may determine the transmission time of the uplink transmission based on the timing advance value obtained for the candidate cell indicated by the cell handover command. The timing advance values ​​for other candidate cells may be cleared, deemed invalid, discarded, or retained without further updating.

[0051] In various implementations discussed herein, when a 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., for performing / initiating uplink time alignment) may be configured by the BS 102 (e.g., a network device, a wireless communication node, a gNB, or a TRP of a candidate cell).

[0052] For example, uplink time alignment may be enabled in the configuration of the candidate cells (e.g., by base station 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 be equal to at least one of the following: the number of candidate cells configured for UE 104, a value determined based on UE capabilities / configuration / performance, a predefined value, and / or a configured value.

[0053] Example Implementation 1: Timing Advance-Related Messages Based on Random Access (RA) Procedure

[0054] In various configurations, the systems and methods of the technical solutions described herein may involve determining and / or indicating timing advance-related information related to candidate cells based on a random access procedure. UE 104 may determine the timing advance value related to the candidate cell based on a message (e.g., timing advance-related information) from BS 102. The message may be determined by BS 102 based on a physical random access channel (PRACH) sent by UE 104. This information may be carried in a random access response (RAR) or a cell handover command.

[0055] In certain aspects, prior to initiating 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 configuration may include at least one of the following: a random access RA preamble index, an RA-RNTI, a PRACH resource, a target power level / threshold on the network receiver side (e.g., the BS side), a maximum number of RA preamble transmissions to be performed before a determination failure (e.g., preambleTransMax), a synchronization signal block (SSB) index, a candidate cell index, and / or a physical cell identifier (PCI). To configure the UE 104, for example, the BS 102 (of the candidate cell of the UE 104) may send a configuration associated with the candidate cell (e.g., a random access channel configuration) to the UE 104. The one or more random access channel configurations for the one or more candidate cells may be associated with the cell-specific random access parameters configured in RACH-ConfigCommon and / or the dedicated random access parameters configured in RACH-ConfigDedicated, and / or may be configured separately.

[0056] In some cases, the PRACH transmission request may be associated with the configuration of one or more candidate cells and / or a timing advance TA acquisition indication (e.g., an indication to acquire / obtain a TA) of one or more candidate cells. The user equipment UE 104 may initiate / perform a random access procedure associated with the candidate cell based on or according to the random access channel configuration (e.g., sometimes generally referred to as configuration) of the candidate cell (e.g., contention-based random access RA) and / or based on a message from the UE 104. In this case, the message from the UE 104 may indicate at least one PRACH transmission parameter of the candidate cell (e.g., contention-free based random access).

[0057] In some cases, the user equipment UE 104 may initiate a random access procedure based on a message from the base station BS102 (e.g., a physical downlink control channel PDCCH command). In this case, the message may include an indication field for indicating the initiation / execution of the random access procedure for the cell. In some configurations, the field may be set / configured to 1, for example, to indicate that the random access procedure is initiated or executed for a candidate cell. The field may be set to 0 to indicate that the random access procedure is initiated or executed for a serving cell. Alternatively, the field may be configured to other binary numbers to indicate whether the random access procedure is initiated for a candidate cell or a serving cell, for example, setting the field to 0 or 1 indicates whether the random access procedure is initiated for a serving cell or a candidate cell, respectively.

[0058] In some implementations, the user equipment (UE) 104 may receive a configuration that includes a maximum number of physical random access channel (PRACH) transmissions associated with a random access procedure for TA acquisition of a candidate cell. The maximum number of PRACH transmissions may be different from a configuration parameter, preambleTransMax, which indicates the maximum number of random access (RA) preamble transmissions that can be performed before a determination of failure is made. When the number of PRACH transmissions associated with a random access procedure reaches the maximum number (e.g., is greater than or equal to the maximum number), the random access procedure may be considered unsuccessfully completed (e.g., failed).

[0059] Example Aspect 1 of Implementation 1

[0060] In various implementations, UE 104 may send a message to BS 102 of a candidate cell to indicate that a random access procedure has been initiated / started for TA acquisition (e.g., obtaining TA-related information) for the candidate cell. This message may be carried in at least one of Msg1, Msg3, and / or MsgA, or indicated by at least one of them. BS 102 may receive the message from UE 104, indicating that a random access procedure has been initiated for TA acquisition for the candidate cell.

[0061] If the message is carried or indicated by Msg1, then after the message is transmitted, the UE 104 may not detect (e.g., avoid, skip, bypass, or disregard) the downlink control information DCI format related to the corresponding random access response RAR scheduling, and / or the UE 104 may not receive the RAR related to the random access procedure. In various cases, not detecting certain information or signals (e.g., DCI format, etc.) may involve the UE 104 skipping (not performing) the detection process. In further cases, not receiving certain information or signals (e.g., RAR, etc.) may refer to or involve the UE 104 instructing the base station BS102 (e.g., via a message) not to send or to ignore / skip sending the RAR. In some cases, not receiving certain information may involve the UE 104 filtering or discarding such information.

[0062] If the message is carried or indicated in Msg3, then after the message is transmitted, UE 104 may not detect the DCI format associated with the physical downlink shared channel (PDSCH) scheduling containing the UE contention resolution indicator and / or may not receive the PDSCH containing the UE contention resolution indicator. If the message is carried in MsgA or indicated by MsgA, then after the message is transmitted, UE 104 may not detect the DCI format with cyclic redundancy check (CRC) bits scrambled by the corresponding MsgB-RNTI (e.g., DCI format 1_0) and / or may not receive MsgB. In some cases, UE 104 may not detect or receive multiple messages or combinations of messages, for example, if multiple messages are indicated (e.g., more than one Msg1, Msg3, and / or MsgA, etc.).

[0063] After UE 104 sends the message, the random access procedure may be considered successfully completed / executed / implemented. The message may include at least one of the following: C-RNTI, RA-RNTI, MsgB-RNTI, random access preamble index, and / or candidate cell index. In some cases, when UE 104 determines a PRACH transmission associated with a PRACH opportunity or random access preamble configured for a candidate cell (e.g., Msg1), UE 104 may not receive a RAR message associated with the PRACH transmission.

[0064] In some implementations, the user equipment UE 104 may receive / obtain / acquire a message from the base station BS 102 of the candidate cell. The message may indicate or indicate termination / cancellation or completion (e.g., successful termination or completion) of the random access procedure and / or successful reception of a physical random access channel PRACH transmission after the UE has sent at least one of Msg1, Msg3, and / or MsgA.

[0065] Subsequently, if a message is received (from BS 102) after sending Msg1, UE 104 may not detect a DCI format associated with a corresponding RAR scheduling associated with a random access procedure and / or may not receive a RAR associated with the random access procedure. If a message is received after sending Msg3, UE 104 may not detect a DCI format associated with scheduling a PDSCH containing a UE contention resolution identifier and / or may not receive a PDSCH containing a UE contention resolution identifier. If a message is received after sending MsgA, UE 104 may not detect a DCI format (e.g., DCI format 1_0) with CRC bits scrambled by the corresponding MsgB-RNTI and / or may not receive MsgB.

[0066] In some cases, a message may have / include a DCI format with CRC bits scrambled by a C-RNTI, a RA-RNTI, and / or a MsgB-RNTI, a DCI format with bits of an indication field set to a specific or predetermined / predefined / configured value, and / or a DCI format including a specific indication field or a specific MAC CE. For example, when the UE 104 receives a DCI format with CRC bits scrambled by an RA-RNTI and bits of a Modulation and Coding Scheme (MCS) field in the DCI format are set to indicate an MCS index (e.g., the index is reserved in a predefined table), the UE 104 may not receive a RAR message associated with the RA-RNTI.

[0067] In another example, when UE 104 receives a DCI format containing a "Completing Random Access" (RA) field, and the field indicates that the random access procedure is completed after sending Msg1, UE 104 may not receive the random access response (RAR) message associated with the DCI format. In another example, when UE 104 receives a TA MAC CE containing a cell identifier or a list of cell identifiers, UE 104 may consider that the random access procedure associated with the cell index has been successfully completed. In some cases, the TA MAC CE may contain one or more timing advance related information, where each timing advance related information may be associated with at least one cell in the one or more cell identifiers (e.g., the list of identifiers).

[0068] In some implementations, UE 104 may receive a random access response (RAR) message from BS 102. In this case, in response to receiving the RAR message, UE 104 may determine that the random access procedure has been successfully completed or terminated based on the RAR message. The RAR message may indicate or provide at least one of the following: a physical cell identifier (PCI), a candidate cell index, a flag (indicating whether the random access procedure is complete), and / or timing advance related information. The uplink UL grant field and / or temporary C-RNTI field may be retained or omitted in the RAR message.

[0069] In some cases, the UE 104 may be configured (e.g., by the BS 102 according to a received configuration) to enable or disable a partial random access procedure for a corresponding candidate cell. For example, if the partial random access procedure is enabled, at least one of the functions / implementations discussed above may be performed for the candidate cell. In another example, if the partial random access procedure is disabled, the UE 104 may perform a random access procedure for the candidate cell using a two-step or four-step random access method. In this example, if the partial random access procedure is disabled, the UE 104 may not perform one or more (or any) of the functions discussed above.

[0070] In some implementations, UE 104 may receive one or more random access response (RAR) messages from BS 102. Each RAR message may indicate respective timing advance related information associated with a corresponding candidate cell. UE 104 may determine an uplink transmission time associated with the cell indicated in the cell handover message based on or according to the timing advance related information associated with the corresponding candidate cell.

[0071] In certain aspects, user equipment UE 104 may receive a cell handover message from base station BS 102 indicating a cell index. The cell index may be associated with one of the configured candidate cells. The cell handover message may indicate timing advance related information associated with the cell index. In certain cases, if the random access procedure is performed / implemented as a two-step random access or a four-step random access, timing advance related information may or may not be present. In other cases, if the random access procedure is performed according to the above implementation, for example, if the random access procedure is completed early, timing advance related information may be present.

[0072] In some implementations herein, completing the random access procedure may correspond to or refer to terminating the random access procedure and / or cancelling subsequent steps of the random access procedure. In some implementations herein, receiving / obtaining (e.g., from the base station 102) a message indicating completion / termination of the random access procedure or successful reception of a PRACH transmission, a random access response RAR message, and / or a cell handover message may be associated with at least one of the following: a Transmission Configuration Indicator (TCI) state, a spatial relationship, a resource set of a downlink reference signal DL-RS, a search space, a control resource set CORESET, and / or a control resource set pool (CORESETPool), which may be associated with a source cell or a candidate cell.

[0073] Example Aspect 2 of Implementation 1

[0074] In certain configurations, to transmit a random access preamble, the random access network temporary identifier RA-RNTI associated with the PRACH opportunity where the random access preamble is transmitted / provided may be calculated as: RA-RNTI = 1 + s_id + 14 × t_id +

[0075] 14×80×f_id+14×80×8×ul_carrier_id+14×80×8×2×cell_id For example, the BS 102 may determine the RA-RNTI based on the index (cell_id) of the candidate cell associated with the random access preamble transmission.

[0076] In some implementations, for the transmission of MsgA, the MsgB-RNTI associated with the PRACH opportunity in which the random access preamble is sent 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 based on cell_id and cell_total.

[0077] In certain implementations herein, s_id may include, correspond to, or refer to the index (e.g., an integer value) of the first OFDM symbol of a PRACH opportunity (e.g., 0 ≤ s_id < 14). t_id may be the index of the first time slot of a PRACH opportunity in a system frame (e.g., 0 ≤ t_id < 80). f_id may be the index of the PRACH opportunity in the frequency domain (e.g., 0 ≤ f_id < 8). ul_carrier_id may be the uplink carrier identifier (e.g., an index or integer value) used for random access preamble transmission (e.g., 0 for NUL carrier, 1 for SUL carrier, or vice versa, depending on the configuration).

[0078] BS 102 may determine the parameter cell_total based on the maximum (supported) number of candidate cells according to the capabilities of UE 104, the configured number of candidate cells, and / or a defined / fixed / configured value. The defined / fixed value may be one of {1, 2, 3, 4, 5, 6, 7} and / or configured as one of {1, 2, 3, 4, 5, 6, 7}. The parameter cell_id may be an integer value equal to or greater than zero (e.g., the index of the cell associated with the random access preamble transmission), such as for the source cell and / or other candidate cells (e.g., not the corresponding candidate cell associated with the corresponding 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 capabilities may be represented by maxNumberTA-Mobility.

[0079] Example Aspect 3 of Implementation 1

[0080] In some aspects, after receiving the cell handover command, UE 104 may not receive a random access response RAR message related to the candidate cell, a message indicating the completion of the random access procedure, and / or a message indicating the successful reception of a physical random access channel PRACH transmission. In some implementations, UE 104 may be configured with a timing advance related timer for the candidate cell. For example, base station BS102 may send / transmit a configuration to configure a timing advance related timer for the candidate cell for UE 104. In this case, when UE 104 receives at least one of the timing advance related information, the message indicating the completion of the random access procedure, and / or the message indicating the successful reception of a PRACH transmission, the MAC entity may start, restart, or stop / cancel / terminate the timing advance related timer. When the timing advance related timer expires / times out, UE 104 may initiate a random access procedure related to the candidate cell.

[0081] In some implementations, the UE 104 may be configured with a time period value (e.g., a predetermined / predefined time period) for the candidate cell. In this case, when the duration since the last / last / previous transmission of Msg1 and / or MsgA exceeds the time period value, or when the duration since the last reception of timing advance-related information, a message indicating completion of a random access procedure, and / or a message indicating successful reception of a PRACH transmission exceeds (or equals) the time period value, the UE 104 may initiate a random access procedure associated with the candidate cell. The time period value may be configured as one or more milliseconds, subslots, slots, subframes, and / or frames, for example, depending on the configuration of the BS 102.

[0082] Example Implementation 2: Timing Advance-Related Messages Based on Sounding Reference Signals

[0083] In various configurations, the systems and methods of the present technical solutions can determine and / or indicate timing advance-related information associated with a candidate cell based on or according to the transmission and / or reception of a sounding reference signal (SRS). The timing advance-related message / signal associated with the candidate cell (corresponding to the base station 102 or the network) can be determined based on a message from the base station 102. The message can be determined by the base station 102 based on an SRS transmitted / provided by the user equipment UE 104. The message can be carried in at least one of a MAC CE and / or a DCI format, as well as other signal forms.

[0084] Example Aspect 1 of Implementation 2

[0085] In certain aspects, prior to transmitting 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, the 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.

[0086] UE 104 may be configured with an SRS resource list (SRS-Resources), an SRS position resource list (SRS-PosResources), an SRS timing advance resource list (SRS-TAResources), an SRS resource set list (SRS-ResourceSets), an SRS position resource set list (SRS-PosResourceSets) and / or an SRS timing advance resource set list (SRS-TAResourceSets). Each resource set (e.g., an SRS resource set) may provide, indicate, or define a set of SRS resources, SRS position resources, and / or SRS timing advance resources, as well as other information. One or more SRS resources or SRS resource sets associated with timing advance acquisition may be related to an SRS timing advance resource list and / or an SRS timing advance resource set, for example. In some cases, one or more SRS resources or SRS resource sets associated with timing advance acquisition may be related to at least one of the following: a candidate cell and / or a downlink reference signal DL-RS of the candidate cell.

[0087] In some cases, UE 104 may send an SRS transmission (e.g., using one or more SRS resources or SRS resource sets) to BS 102 of a candidate cell. The SRS transmission may correspond to an SRS activation or deactivation MAC CE and / or DCI signaling or format. In various cases, the SRS transmission may be associated with a candidate cell. A field in the SRS activation or deactivation MAC CE or DCI signaling may indicate that the SRS transmission is activated / enabled or triggered for timing advance acquisition of the candidate cell.

[0088] In other cases, for example, if the time period that has passed since the last transmission of an SRS for uplink timing advance acquisition is greater than (or equal to) a threshold, or the time period that has passed since the last reception of a network message (e.g., a message from BS 102) is greater than (or equal to) a threshold (e.g., a time limit), then UE 104 may transmit an SRS transmission for uplink timing advance acquisition. The threshold may be configured, predetermined, or predefined for each candidate cell and / or predefined based on or according to the configuration of each candidate cell. The network message may indicate a timing advance-related message or a candidate cell index associated with the candidate cell and / or indicate that an SRS transmission for uplink timing advance acquisition has been successfully received.

[0089] In some implementations, UE 104 may be configured with a timing advance-related timer for a candidate cell. This timer may be started or restarted when UE 104 receives a message (e.g., a network message) from BS 102. If the timer expires, UE 104 may transmit an SRS (transmission) for uplink timing advance acquisition of the candidate cell. The network message may indicate timing advance-related information (or message) associated with the candidate cell or a candidate cell index, and / or indicate that the SRS transmission for uplink timing advance acquisition has been successfully received.

[0090] Example Aspect 2 of Implementation 2

[0091] In certain aspects, the UE 104 may determine an uplink transmission time for an SRS transmission associated with timing advance acquisition of a candidate cell based on or in accordance with a timing advance value and / or downlink timing. In certain configurations, the timing advance value may include, correspond to, or be one of: zero, a timing advance value associated with a source cell (e.g., an integer value), a timing advance value associated with a cell other than the candidate cell (e.g., BS 102), or a timing advance value associated with the candidate cell. The UE 104 may determine the timing advance value associated with the candidate cell based on or in accordance with at least one of the steps / features discussed in conjunction with example implementation 1 or example implementation 3.

[0092] In some configurations, the downlink timing may include at least one of the following: downlink timing associated with a source cell, downlink timing associated with a candidate cell, or downlink timing associated with a cell other than the candidate cell. In some cases, the UE 104 may determine the transmit power of the SRS transmission based on open-loop power control parameters configured for the SRS transmission and / or a path loss calculated / determined by the UE 104 using a reference signal associated with the SRS transmission.

[0093] In some cases, the UE 104 may determine the transmit power of the SRS transmission based on the open-loop power control parameters configured for the SRS transmission and / or the path loss calculated by the UE 104 using a reference signal associated with the SRS transmission and a transmit power control (TPC) command included in the DCI signaling / format. The DCI signaling may be DCI formats 2-3, the DCI that triggers / activates the SRS transmission, the DCI associated with the most recent PUSCH transmission preceding the SRS transmission, and / or the DCI format used for PDCCH commands.

[0094] Example Aspect 3 of Implementation 2

[0095] In certain aspects, after an SRS transmission for uplink timing advance acquisition, the UE 104 may receive a message / information / signal indicating a candidate cell index. The UE 104 may cancel / terminate the activated / triggered SRS transmission associated with the candidate cell for uplink timing advance acquisition. In certain other aspects, the UE 104 may not receive (e.g., the first) message indicating the candidate cell index after / starting from / within a certain time period / window / duration relative to the SRS transmission for uplink timing advance acquisition associated with the candidate cell. The time period may be configured for the SRS resource, SRS resource set, and / or candidate cell associated with the SRS transmission. In this case, the UE 104 may send another (e.g., a second) message to the BS 102 to indicate that the timing advance acquisition of the candidate cell failed or was unsuccessful.

[0096] In some cases, UE 104 may send a message indicating timing advance related information. UE 104 may determine the uplink timing advance value associated with the candidate cell indicated in the message based on the timing advance related information. In various aspects, the message may be carried in a MAC CE and / or DCI format, as well as other signaling.

[0097] Example implementation 3: Timing advance related messages based on downlink timing

[0098] In various configurations, the systems and methods of the present technical solutions may determine and / or indicate timing advance-related information associated with a candidate cell based on or according to the downlink timing of the candidate cell and at least one other cell. UE 104 may determine the downlink timing of the cell based on a downlink reference signal DL-RS associated with the received cell. UE 104 may determine timing advance-related information associated with the candidate cell based on the received DL-RS associated with the candidate cell and the received DL-RS associated with another cell. The at least one other cell may be a source cell or another cell different from the candidate cell (e.g., a second candidate cell).

[0099] In some implementations, UE 104 may determine a timing advance value associated with a candidate cell based on a difference (e.g., delta) in downlink timing between the candidate cell and another cell and / or timing advance related information associated with the other cell. For example, the difference in downlink timing of downlink frames of the source cell and the candidate cell may correspond to or be represented as T rx_diff If the downlink timing of the source cell's downlink frame is earlier than the downlink timing of the candidate cell, then T rx_diff Otherwise, if the downlink timing of the source cell's downlink frame is later than that of the candidate cell, then T rx_diff The timing advance value associated with the source cell can be expressed as N TA，0 For example, UE 104 may determine the timing advance value associated with the candidate cell as N TA,0 +2×T rx_diff .

[0100] In another example, the difference in downlink timing between the downlink frames of the source cell and the candidate cell may be T rx_diff , the timing advance command associated with the source cell can be T A,0 In this example, UE 104 may determine the timing advance value associated with the candidate cell as N TA，new =N TA，old +N TAC，0 +2×T rx_diff , where N TA，old It can represent the current TA value of the candidate cell, N TAC，0 Based on T A,0 Sure.

[0101] In some implementations, the UE 104 may receive / obtain / retrieve a message (e.g., from a candidate cell) that indicates or includes a TA assistance value associated with the candidate cell. Upon receiving the message, the UE 104 may determine the timing advance value associated with the candidate cell based on or in accordance with at least one of: a difference in downlink timing between the candidate cell and another cell, timing advance-related information associated with the other cell, and / or the TA assistance value.

[0102] For example, the difference in downlink timing between the downlink frames of the source cell and the candidate cell can be T rx_diff , the timing advance value associated with the source cell may be N TA，0 , TA auxiliary value can be N TA_delta UE 104 may determine the timing advance value associated with the candidate cell according to the following formula: N TA，0 +2×T rx_diff +N TA_delta In another example, the difference in downlink timing between the downlink frames of the source cell and the candidate cell may be T rx_diff , the timing advance command associated with the source cell can be T A，0 In this example, UE 104 may determine the timing advance value associated with the candidate cell as N TA，new =N TA，old +N TAC，0 +2×T rx_diff +N TA_delta In various configurations, the TA assistance value may be carried in RRC messages, MAC CE and / or DCI formats, and other types of signaling.

[0103] In some implementations, when the difference between the downlink timing of the candidate cell and the downlink timing of the other cell is greater than (or in some cases equal to) a threshold, SRS and / or PRACH transmissions for timing advance acquisition can be triggered or activated / performed. For example, the UE 104 can use the downlink timing of the corresponding candidate cell and / or the other cell as a reference to determine the transmission time of the SRS and / or PRACH transmissions. In some cases, the UE 104 can determine the transmission time of the SRS and / or PRACH transmissions based on a timing advance value, which may be the same as the timing advance value described in example aspect 2 of implementation 2, for example.

[0104] In some implementations, when the downlink timing difference between the candidate cell and another cell is greater than a threshold, the UE 104 may send a message to the BS 102 (e.g., the serving cell), the message including the downlink timing difference between the candidate cell and the other cell and an index of the candidate cell. In various implementations discussed herein, the threshold may be configured / updated / provided for the candidate cell and / or predefined based on the configuration of the candidate cell.

[0105] Now refer to Figure 5 , which shows a flow chart of a method 500 for uplink timing alignment for inter-cell mobility. The method 500 may be implemented using or performed by any of the components described above (e.g., UE 104 or 204 and BS 102 or 202, etc.). In summary, at operation 702, a wireless communication node may send a configuration to a wireless communication device. At operation 704, the wireless communication device may receive the configuration from the wireless communication node. At operation 706, the wireless communication device may send a transmission to the wireless communication node. At operation 708, the wireless communication node may receive the transmission from the wireless communication device.

[0106] More specifically, at operation 702, a wireless communication node (e.g., a base station BS, gNB, or a transmission reception point TRP) of a candidate cell of a wireless communication device (e.g., a user equipment UE) may transmit / transmit a configuration related to the candidate cell to the wireless communication device. The configuration may configure the wireless communication device to perform timing advance (TA) acquisition during or before cell handover. At operation 704, the wireless communication device may receive / acquire / obtain the configuration related to the candidate cell from the wireless communication node.

[0107] At operation 706, the wireless communication device may send a transmission to the 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.

[0108] In various configurations, the configuration may include configuration of a random access channel. The transmission may include a physical random access channel (PRACH) transmission. In such configurations, the wireless communication device may initiate / perform a random access procedure associated with a candidate cell based on the configuration or based on a message / information from the wireless communication node indicating at least one PRACH transmission parameter for the candidate cell.

[0109] In some implementations, a wireless communication node may receive a message from a wireless communication device indicating that a random access procedure for acquiring timing advance (TA)-related information of a candidate cell has been initiated. In some cases, at least one of the following conditions exists: after sending the message, the wireless communication device may not detect (e.g., skip, avoid, or bypass detection) a downlink control information (DCI) format related to a random access response (RAR) scheduling associated with the random access procedure and / or may not receive the RAR; after sending the message, the wireless communication device may not detect a DCI format related to a physical downlink shared channel (PDSCH) scheduling including a user equipment (UE) contention resolution identifier and / or may not receive a PDSCH including the UE contention resolution identifier; after sending the message, the wireless communication device may not detect a DCI format with cyclic redundancy check (CRC) bits scrambled by a corresponding MsgB-RNTI and / or may not receive an MsgB; and / or the message may include at least one of the following: a C-RNTI, a RA-RNTI, an MsgB-RNTI, a random access preamble index, and / or a candidate cell index.

[0110] In some implementations, the wireless communication node may send a message to the wireless communication device indicating termination or completion of the random access procedure and / or successful reception / acquisition of the PRACH transmission after receiving Msg1, Msg3, and / or MsgA. Depending on whether the message is sent after receiving at least one of Msg1, Msg3 and / or MsgA, at least one of the following situations may occur: the wireless communication device may not detect the downlink control information DCI format related to the random access response (RAR) scheduling related to the random access process, and / or may not receive the RAR; the wireless communication device may not detect the DCI format related to the physical downlink shared channel PDSCH scheduling containing the user equipment UE contention resolution identifier, and / or may not receive the PDSCH containing the UE contention resolution identifier; the wireless communication device may not detect the DCI format with the CRC bit scrambled by the corresponding MsgB-RNTI, and / or may not receive MsgB; and / or the message may include a DCI format with the CRC bit scrambled by the C-RNTI, RA-RNTI and / or MsgB-RNTI, and / or a DCI format with an indication field and its bit set to a specific value, and / or a DCI format with a specific indication field, and / or specific media access control element MAC CE signaling. In response to these communications (eg, partial random access procedures) between the wireless communication node and the wireless communication device, the system and method may reduce / minimize delays in cell switching because information is communicated before or during the cell switching.

[0111] In some implementations, at least one of the following conditions may occur: a wireless communication node may send a random access response (RAR) message to a wireless communication device indicating termination or successful completion of a random access procedure, wherein the RAR message may indicate at least one of the following: a physical cell identifier (PCI), a candidate cell index, a flag indicating whether the random access procedure is completed or terminated, 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 the partial random access procedure is enabled, any one or more steps of the implementations or features described above are performed, and / or when the partial random access procedure is disabled, random access may be performed according to a two-step random access or four-step random access procedure; the wireless communication node may send one or more RAR messages to the wireless communication device, each RAR message may indicate TA-related information associated with a corresponding candidate cell, and the wireless communication device may determine (or calculate) an uplink transmission time associated with the corresponding candidate cell indicated by a cell handover message based on or according to at least the TA-related information associated with the corresponding candidate cell; and / or the wireless communication node may send a cell handover message to the wireless communication device indicating at least one of the cell index and / or TA-related information associated with the cell index.

[0112] In some implementations, at least one of the following determinations may be performed while taking into account the cell index: a wireless communication node for transmitting a random access preamble may determine an RA-RNTI associated with a PRACH opportunity for transmitting the random access preamble based on an index cell_id of a candidate cell associated with the transmission of the random access preamble; and / or a wireless communication node for transmitting MsgA may determine an MsgB-RNTI associated with a PRACH opportunity for transmitting the random access preamble based on cell_id and cell_total. In this case, cell_total may be or correspond to a maximum number of candidate cells supported according to wireless communication device capabilities, and / or a configured number of candidate cells, and / or a defined / fixed / configured value. cell_id may be an integer value equal to or greater than zero, and / or a numerical value less than or equal to cell_total. cell_total may be configured as one of {1, 2, 3, 4, 5, 6, 7}.

[0113] In some implementations, a wireless communication node may send a configuration to a wireless communication device to configure a timing advance (TA)-related timer associated with a candidate cell (e.g., for contention-based random access (CBRA) for acquiring a TA during cell handover) for the wireless communication device. In this case, when the timing advance-related timer expires, the wireless communication device may initiate a random access procedure associated with the candidate cell.

[0114] In various configurations, at least one of the following situations exists: the configuration may include one or more sounding reference signal SRS resources and / or SRS resource sets associated with timing advance TA acquisition; the transmission may include SRS transmission; the SRS transmission may be used for uplink timing advance acquisition of the candidate cell; and / or one or more SRS resources and / or SRS resource sets may be associated with at least one of the following: the candidate cell, and / or the downlink reference signal DL-RS of the candidate cell.

[0115] In some implementations, a wireless communication node may receive an SRS transmission from a wireless communication device, wherein at least one of the following situations exists: the SRS transmission may correspond to SRS activation or deactivation media access control element MAC CE signaling or downlink control information DCI signaling; a field in 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 a candidate cell; and / or the SRS transmission may be associated with a candidate cell.

[0116] In some implementations, the wireless communication device may determine an uplink transmission time for an SRS transmission associated with timing advance acquisition of a candidate cell based at least on or in accordance with at least one timing advance value and downlink timing, including at least one of the following: the timing advance value may include: (i) zero, (ii) a timing advance value associated with a source cell, (iii) a timing advance value associated with a cell different from the candidate cell, and / or (iv) 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.

[0117] In certain aspects, at least one of the following situations exists: after an SRS transmission for uplink timing advance acquisition, the wireless communication device may receive a message indicating a candidate cell index and cancel the activated / initiated or triggered SRS transmission for uplink timing advance acquisition associated with the candidate cell; or, the wireless communication device does not receive a message indicating a candidate cell index (e.g., a first message) within a time period after the SRS transmission for uplink timing advance acquisition associated with the candidate cell, where the time period may be configured for the SRS resource, SRS resource set and / or candidate cell associated with the SRS transmission, and the wireless communication device may send another message (e.g., a second message) to the wireless communication node to indicate that the uplink timing advance acquisition of the candidate cell has failed (e.g., was unsuccessful).

[0118] Although various embodiments of the present solution have been described above, it should be understood that these embodiments are presented as examples only and not as limitations. Similarly, various diagrams may depict example architectures or configurations, which are intended to enable those skilled in the art to understand the example features and functionality of the present solution. However, those skilled in the art should understand that the present solution is not limited to the example architectures or configurations shown, but can be implemented using various alternative architectures and configurations. Furthermore, those skilled in the art should understand that one or more features of one embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of the present invention should not be limited in any way by the exemplary embodiments described above.

[0119] Furthermore, it should be understood that any reference to an element herein using terms such as "first," "second," etc., does not generally limit the number or order of those elements. Rather, these terms are used herein as a convenient means of distinguishing between two or more elements or multiple instances of an element. Thus, reference to a first and a second element does not necessarily mean that only two elements may be used, nor does it mean that the first element must be placed before the second element in some manner.

[0120] Furthermore, persons of ordinary skill in the art will appreciate that information and signals can be represented using a variety of different technologies and methods. For example, data, instructions, commands, information, signals, bits, and symbols mentioned in the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or light particles, or any combination thereof.

[0121] Those of ordinary skill in the art will further understand that any of the various exemplary logic blocks, modules, processors, means, circuits, methods, and functions described in conjunction with the aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of the two), firmware, various programs or design codes containing instructions (for convenience, they may be referred to herein as "software" or "software modules"), or any combination of these technologies. To clearly illustrate this interchangeability of hardware, firmware, and software, various exemplary components, blocks, modules, circuits, and steps have been described above generally in terms of their functions. Whether these functions are implemented as hardware, firmware, software, or a combination of these technologies depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functions in various ways for each specific application, but these implementation decisions do not result in a departure from the scope of the present invention.

[0122] In addition, those skilled in the art will understand that the various exemplary logic blocks, modules, devices, components and circuits described herein may 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. These logic blocks, modules and circuits may also include antennas and / or transceivers to communicate with various components within a network or within a device. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors and a DSP core, or any other suitable configuration that performs the functions described herein.

[0123] If implemented in software, these functions may be stored as one or more instructions or codes on a computer-readable medium. Thus, the steps of the methods or algorithms disclosed herein may be implemented as software stored on a computer-readable medium. Computer-readable media include computer storage media and communication media, the latter including any medium that enables a computer program or code to be transferred from one place to another. A storage medium may be any available medium that can be accessed by a computer. For example, but not limited to, such computer-readable media may 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 store the desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0124] As used in this document, the term "module" refers to software, firmware, hardware, and any combination of these elements used to perform the relevant functions described herein. In addition, for ease of discussion, various modules are described as independent modules; however, it is obvious to those skilled in the art that, depending on the embodiments of the present solution, two or more modules can be combined into a single module that performs the relevant functions.

[0125] Furthermore, in embodiments of the present solution, memory or other storage devices as well as communication components may be employed. For clarity, the above description describes embodiments of the present solution with reference to different functional units and processors. However, it will be apparent that functionality may be distributed among different functional units, processing logic elements, or domains in any suitable manner without departing from the present solution. For example, functions described as being performed by separate processing logic elements or controllers may also be performed by the same processing logic element or controller. Therefore, reference to a particular functional unit refers only to a suitable means of providing the described functionality, and does not indicate a strict logical or physical structure or organization.

[0126] Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of the general principles defined herein. Therefore, the present invention 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 claims herein.

Claims

1. A method comprising: a wireless communication node for a candidate cell of a wireless communication device, sending a configuration associated with the candidate cell to the wireless communication device; as well as The wireless communication node receives transmissions sent by the wireless communication device according to the configuration.

2. The method according to claim 1, wherein: The configuration includes configuration of a random access channel; and The transmission includes physical random access channel PRACH transmission.

3. The method according to claim 2, wherein: The wireless communication device initiates 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 of the candidate cell.

4. The method according to claim 2, comprising: The wireless communication node receives a message from the wireless communication device, the message indicating that a random access procedure for acquiring timing advance TA-related information of the candidate cell is initiated.

5. The method according to claim 4, wherein at least one of the following: After sending the message, the wireless communication device does not detect a downlink control information DCI format associated with scheduling of a random access response RAR related to the random access procedure, or does not receive the RAR; After sending the message, the wireless communication device does not detect a DCI format associated with scheduling of a physical downlink shared channel (PDSCH) including a user equipment (UE) contention resolution identifier, or does not receive the PDSCH including the UE contention resolution identifier; After sending the message, the wireless communication device does not detect a DCI format having cyclic redundancy check (CRC) bits scrambled by a corresponding message MsgB radio network temporary identifier MsgB-RNTI, or does not receive MsgB; The message includes at least one of the following: a cell radio network temporary identifier C-RNTI, a random access radio network temporary identifier RA-RNTI, a MsgB-RNTI, a random access preamble index, and a candidate cell index.

6. The method according to claim 2, comprising: After receiving the message Msg1, the message Msg3, or the message MsgA, the wireless communication node sends a message to the wireless communication device indicating termination or completion of the random access procedure, or successful reception of the PRACH transmission, wherein at least one of the following is performed: The wireless communication device does not detect a DCI format associated with scheduling of a 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 PDSCH including a UE contention resolution identifier, or does not receive the PDSCH including the UE contention resolution identifier; The wireless communication device does not detect a DCI format having cyclic redundancy check (CRC) bits scrambled by a corresponding MsgB-RNTI, or does not receive an MsgB; or The message includes a DCI format with CRC bits scrambled by C-RNTI, RA-RNTI or MsgB-RNTI, or a DCI format with an indication field with bits set to a specific value, or a DCI format with a specific indication field, or specific media access control element MAC CE signaling.

7. The method according to claim 2, comprising at least one of the following: The wireless communication node sends a RAR message to the wireless communication device indicating termination or successful completion of a random access procedure, wherein the RAR message indicates at least one of the following: a physical cell identifier (PCI), a candidate cell index, a flag for indicating whether the random access procedure is completed or terminated, and TA-related information; The wireless communication node sends a configuration for enabling or disabling the wireless communication device to perform a partial random access procedure, wherein when the partial random access procedure is enabled, one or more steps of any one of claims 1 to 7 are performed, and when the partial random access procedure is disabled, random access is performed according to a two-step random access or a four-step random access procedure; The wireless communication node sends one or more RAR messages to the wireless communication device, wherein each of the one or more RAR messages indicates TA-related information associated with a corresponding candidate cell; and the wireless communication device determines, based on at least the TA-related information associated with the corresponding candidate cell, an uplink transmission time associated with the corresponding candidate cell indicated by the cell handover message; The wireless communication node sends a cell handover message to the wireless communication device, where the cell handover message indicates at least one of the following: a cell index and TA-related information associated with the cell index.

8. The method according to claim 2, comprising at least one of the following: The wireless communication node determines, for transmission of a random access preamble, an RA-RNTI associated with a PRACH opportunity for transmission of the random access preamble based on an index cell_id of a candidate cell associated with transmission of the random access preamble; or The wireless communication node determines, for transmission of MsgA, a MsgB-RNTI associated with a PRACH opportunity for transmitting the random access preamble according to the cell_id and the total number of cells cell_total; in, cell_total is the maximum number of candidate cells supported according to the capabilities of the wireless communication device, the number of configured candidate cells, or a defined value, where the defined value is one of {1, 2, 3, 4, 5, 6, 7}, and cell_id is an integer value greater than or equal to zero and less than or equal to the cell_total value.

9. The method according to claim 2, comprising: The wireless communication node sends a configuration to the wireless communication device to configure a TA-related timer for the candidate cell for the wireless communication device, When the TA-related timer expires, the wireless communication device initiates a random access process associated with the candidate cell.

10. The method of claim 1, wherein at least one of the following: The configuration includes configuration of one or more sounding reference signal SRS resources or SRS resource sets related to TA acquisition; The transmission includes SRS transmission; The SRS transmission is used for uplink TA acquisition of the candidate cell; or The one or more SRS resources or SRS resource sets are associated with at least one of the following: the candidate cell, or a downlink reference signal DL-RS of the candidate cell.

11. The method according to claim 10, comprising: The wireless communication node receives the SRS transmission from the wireless communication device, wherein at least one of: The SRS transmission corresponds to SRS activation or deactivation media access control element MAC CE signaling or DCI signaling; The SRS activation or deactivation field in the MAC CE signaling or DCI signaling indicates that the SRS transmission is activated or triggered for TA acquisition of the candidate cell; or The SRS transmission is associated with the candidate cell.

12. The method according to claim 10, wherein: The wireless communication device determines an uplink transmission time of the SRS transmission associated with TA acquisition of the candidate cell based on at least a TA value and downlink timing, wherein at least one of the following: The TA value includes: zero; a TA value associated with a source cell; a TA value associated with a cell different from the candidate cell; or a TA value associated with the candidate cell; or The downlink timing includes: downlink timing associated with the source cell; downlink timing associated with the candidate cell; or downlink timing associated with a cell other than the candidate cell.

13. The method according to claim 10, wherein at least one of the following: After the SRS transmission for uplink TA acquisition, the wireless communication device receives a message indicating the candidate cell index and cancels the transmission of the SRS associated with the candidate cell that is activated or triggered for uplink TA acquisition; or The wireless communication device does not receive a message indicating an index of the candidate cell within a time period relative to an SRS transmission for uplink TA acquisition associated with the candidate cell, wherein the time period is configured for an SRS resource, an SRS resource set, or the candidate cell associated with the SRS transmission, and the wireless communication device sends another message to the wireless communication node to indicate that uplink TA acquisition for the candidate cell has failed.

14. A method comprising: The wireless communication device receives a configuration associated with a candidate cell from a wireless communication node of the candidate cell; as well as The wireless communication device sends a transmission to the wireless communication node according to the configuration.

15. A non-transitory computer-readable medium storing instructions, which, 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 execute the method of any one of claims 1 to 14.

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