Multiple time alignment timers

Abstract

A method is disclosed that includes determining whether to flush one or more hybrid automatic repeat request (HARQ) buffers based on expiration of at least one of at least two time alignment timers.

Description

[Technical Field]

[0001] The following exemplary embodiments relate to wireless communication. [Background technology]

[0002] In wireless communication systems, user equipment can apply timing advance to adjust the timing of uplink frames in order to match downlink frames in the time domain. However, there is a challenge in how to apply timing advance when, for example, user equipment transmits to at least two transmit / receive points simultaneously. [Overview of the project]

[0003] The scope of protection required for various exemplary embodiments is defined by the independent claims. Where any exemplary embodiments and features described herein are not covered by the independent claims, they are to be interpreted as useful examples for understanding various embodiments.

[0004] According to one embodiment, the provided device includes at least one processor and at least one memory that stores instructions, when executed by the at least one processor, causing the device to at least determine whether or not to flush one or more hybrid automatic retransmission request (HARQ) buffers based on the expiration of at least one of two time alignment timers.

[0005] In another embodiment, there is provided an apparatus that includes means for determining whether or not to flush one or more hybrid automatic retransmission request (HARQ) buffers based on the expiration of at least one of at least two time alignment timers.

[0006] In another embodiment, a method is provided which includes determining whether to flush one or more Hybrid Automatic Retransmission Request (HARQ) buffers based on the expiration of at least one of at least two time alignment timers.

[0007] In another embodiment, a computer program is provided which, when executed by the device, causes the device to at least determine whether or not to flush one or more Hybrid Automatic Retransmission Request (HARQ) buffers based on the expiration of at least one of two time alignment timers.

[0008] In another embodiment, the device is provided with a computer-readable medium that, when executed by the device, causes the device to at least determine whether or not to flush one or more Hybrid Automatic Retransmission Request (HARQ) buffers based on the expiration of at least one of two time alignment timers.

[0009] In another embodiment, the device is provided with a non-temporary computer-readable medium that, when executed by the device, causes the device to at least determine whether or not to flush one or more Hybrid Automatic Retransmission Request (HARQ) buffers based on the expiration of at least one of two time alignment timers. [Brief explanation of the drawing]

[0010] In the following sections, various exemplary embodiments will be described in more detail with reference to the attached drawings. [Figure 1] Figure 1 shows an example of a cellular communication network. [Figure 2] Figure 2 illustrates the concept of timing advance. [Figure 3]Figure 3 shows simultaneous (or parallel) multi-panel uplink transmission. [Figure 4] Figure 4 shows a flowchart according to an exemplary embodiment. [Figure 5] Figure 5 shows an example of a representative embodiment. [Figure 6] Figure 6 shows a flowchart according to an exemplary embodiment. [Figure 7] Figure 7 shows a flowchart according to an exemplary embodiment. [Figure 8] Figure 8 shows a flowchart according to an exemplary embodiment. [Figure 9] Figure 9 shows a flowchart according to an exemplary embodiment. [Figure 10] Figure 10 shows a flowchart according to an exemplary embodiment. [Figure 11] Figure 11 shows a flowchart according to an exemplary embodiment. [Figure 12] Figure 12 shows an example of an exemplary embodiment. [Figure 13] Figure 13 shows a flowchart according to an exemplary embodiment. [Figure 14] Figure 14 shows an exemplary embodiment of the apparatus. [Modes for carrying out the invention]

[0011] The following embodiments are illustrative. While this specification may refer to “a certain,” “one,” or “several” embodiments in some places, this does not necessarily mean that each reference is made to the same embodiment, or that certain features apply to only one embodiment. Other embodiments may also be provided by combining single features from different embodiments.

[0012] In the following, without limiting the exemplary embodiments to such an architecture, as an example of an access architecture to which the exemplary embodiments may be applied, various exemplary embodiments will be described using a radio access architecture based on Long-Term Evolution Advanced (LTE-Advanced, LTE-A), New Radio (NR, 5G), Beyond 5G, or Sixth Generation (6G). It will be apparent to those skilled in the art that the exemplary embodiments can also be applied to other types of communication networks having appropriate means by appropriately adjusting the parameters and procedures. Examples of other options for a suitable system include Universal Mobile Telecommunications System (UMTS) radio access network (UTRAN, or E-UTRAN), Long-Term Evolution (LTE, substantially the same as E-UTRA), Wireless Local Area Network (WLAN, or Wi-Fi (registered trademark)), Worldwide Interoperability for Microwave Access (WiMAX), Bluetooth (registered trademark), Personal Communication Service (PCS), ZigBee (registered trademark), Wideband Code Division Multiple Access (WCDMA (registered trademark)), a system using Ultra-Wideband (UWB) technology, a sensor network, Mobile Ad Hoc Networks (MANETs), Internet Protocol Multimedia Subsystem (IMS), or a combination thereof.

[0013] FIG. 1 shows an example of a simplified system architecture showing some elements and functional entities, all of which are logical units, and their implementation may be different from that shown. The connections shown in FIG. 1 are logical connections and may be different from actual physical connections. It will be apparent to those skilled in the art that the system may include functions and structures other than those shown in FIG. 1.

[0014] However, the exemplary embodiments are not limited to the systems exemplified, and those skilled in the art can apply this solution to other communication systems having the necessary characteristics.

[0015] The example in Figure 1 shows a portion of an exemplary wireless access network.

[0016] Figure 1 shows an access node 104, such as an evolved node B (eNB, or abbreviated as eNodeB) or next-generation node B (gNB, or abbreviated as gNodeB), providing a wireless cell, and user devices 100 and 102 configured to wirelessly connect via one or more communication channels within the wireless cell. The physical link from the user devices to the access node may be called an uplink (UL) or reverse link, and the physical link from the access node to the user devices may be called a downlink (DL) or forward link. User devices can also communicate directly with other user devices via sidelink (SL) communication. It should be understood that the access node or its functions can be implemented using any entity such as a node, host, server, or access point that is suitable for such applications.

[0017] The communication system may include one or more access nodes, which may be configured to communicate with each other via wired or wireless links designed for that purpose. These links may be used for signaling purposes. An access node may also be a computing device configured to control the wireless resources of the communication system to which it is connected. An access node may also be referred to as a base station, base transceiver base station (BTS), access point, or any other type of interface device, including a relay station capable of operating in a wireless environment. An access node may include or be connected to a transceiver. A connection may be provided from the transceiver of an access node to an antenna unit that establishes a bidirectional wireless link to user equipment. The antenna unit may comprise multiple antennas or antenna elements. Furthermore, an access node may be connected to a core network 110 (CN, or next-generation core NGC). Depending on the system, the CN counterpart may be a Serving Gateway (S-GW, which routes and forwards user data packets), a Packet Data Network Gateway (P-GW) for providing connectivity of user equipment to the external packet data network, a User Plane Function (UPF), a Mobility Management Entity (MME), an Access and Mobility Management Function (AMF), or a Location Management Function (LMF), etc.

[0018] User equipment indicates one type of equipment to which resources on the air interface are allocated, or may be allocated, and therefore any functions described herein in conjunction with user equipment may be implemented together with corresponding equipment such as relay nodes.

[0019] An example of such a relay node is a Layer 3 relay (self-backhauling relay) directed to an access node. Self-backhauling relay nodes are sometimes called integrated access and backhaul (IAB) nodes. An IAB node may comprise two logical parts: a mobile terminal (MT) part responsible for the backhaul link (i.e., the link between the IAB node and the donor node, also known as the parent node), and a distributed unit (DU) part responsible for the access link (i.e., the child link between the IAB node and the user equipment), and / or the access link between the IAB node and other IAB nodes (multi-hop scenarios).

[0020] Another example of such relay nodes is a Layer 1 relay called a repeater. A repeater can amplify signals received from an access node and forward them to user equipment, and / or amplify signals received from user equipment and forward them to the access node.

[0021] User equipment may also be called subscriber units, mobile stations, remote terminals, access terminals, user terminals, terminal equipment, or user devices (UE). User equipment may refer to portable computing devices, including wireless mobile communication equipment that operates with or without a subscriber identification module (SIM), and may include, but is not limited to, mobile stations (cell phones), smartphones, personal digital assistants (PDAs), handsets, devices using wireless modems (such as alarm devices or measuring devices), laptops and / or touchscreen computers, tablets, game consoles, notebooks, multimedia equipment, RedCap (RedCap) equipment, wireless sensor equipment, or any equipment integrated into a vehicle.

[0022] User devices may be almost exclusively dedicated uplink devices, such as cameras or video cameras that load images or video clips onto the network. User devices may also be capable of operating on an Internet of Things (IoT) network, a scenario that provides the ability to transfer data to things over a network without requiring human-to-human or human-to-computer interaction. User devices may also utilize the cloud. In some applications, user devices may comprise small, portable or wearable devices with wireless components (such as watches, earphones, or glasses), with computations performed in the cloud or on other user devices. User devices (or Layer 3 relay nodes in exemplary embodiments) may be configured to perform one or more of the functions of user devices.

[0023] The various technologies described herein can also be applied to cyber-physical systems (CPS) (systems of collaborative computing elements that control physical entities). CPS can enable the implementation and use of a large number of interconnected ICT devices (sensors, actuators, processors, microcontrollers, etc.) embedded in physical objects in various locations. Mobile cyber-physical systems are a subcategory of cyber-physical systems, and the physical system may have its own mobility. Examples of mobile-physical systems include mobile robots and electronic devices carried by humans or animals.

[0024] Furthermore, although the device has been described as a single entity, it can also implement various units, processors, and / or memory units (not all of which are shown in Figure 1).

[0025] 5G utilizes multiple-input multiple-output (MIMO) antennas, enabling a greater number of base stations or nodes (the so-called small cell concept) than LTE, including macrosites that operate in cooperation with smaller base stations, and employs various radio technologies depending on service needs, use cases, and / or available frequencies. 5G mobile communications can support a wide range of use cases and related applications, including video streaming, augmented reality, various data sharing methods, and various forms of machine-type applications (vehicle safety, various sensors, (large-scale) machine-type communications (mMTC) including real-time control, etc.). 5G has multiple radio interfaces, such as sub-6GHz, centimeter wave, and millimeter wave, and can be integrated with existing legacy radio access technologies such as LTE. Integration with LTE can be implemented, at least in the initial stages, as a system where macro coverage is provided by LTE, and 5G radio interface access is provided from small cells through aggregation to LTE. In other words, 5G can support both RAT-to-RAT operations (LTE-5G, etc.) and RI-to-RI operations (radio interface-to-radio interface operations, sub-6GHz, centimeter wave, millimeter wave, etc.). One concept likely to be used in 5G networks is network slicing, where multiple independent, dedicated virtual subnetworks (network instances) are created within essentially the same infrastructure, allowing them to run services with different latency, reliability, throughput, and mobility requirements.

[0026] The current architecture of LTE networks can be fully distributed wirelessly and fully centralized in the core network. Low-latency applications and services of 5G need to bring content closer to the wireless, connected to local breakout and multi-access edge computing (MEC). 5G will enable analysis and knowledge generation at the data source. This approach may require leveraging resources that are not constantly connected to the network, such as laptops, smartphones, tablets, and sensors. MEC can provide a distributed computing environment for hosting applications and services. It also has the ability to store and process content near the cellular subscriber to reduce response times. Edge computing can cover a wide range of technologies, including wireless sensor networks, mobile data collection, mobile signature analysis, collaborative distributed peer-to-peer ad-hoc networking, local cloud / fog computing and grid / mesh computing, due computing, mobile edge computing, cloudlets, distributed data storage and search, autonomous self-healing networks, remote cloud services, augmented and virtual reality, data caching, the Internet of Things (where large-scale connectivity and / or latency are critical), and critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, and healthcare applications).

[0027] The communication system can communicate with other networks such as the public switched telephone network and the Internet 112, and utilize services provided by them. The communication network can also support the use of cloud services; for example, at least a portion of the core network operation can be implemented as a cloud service (illustrated as "cloud" 114 in this embodiment). Furthermore, the communication system may include a central control entity, and can provide facilities for various operators' networks to cooperate, for example, in spectrum sharing.

[0028] Edge clouds can be deployed in radio access networks (RANs) by leveraging network function virtualization (NFV) or software-defined networking (SDN). Using an edge cloud may mean, at least partially, that the access node's operations are performed on a remote radio head (RRH) or radio unit (RU), or on a server, host, or node operably connected to an access node containing a radio unit. The node's operations may also be distributed across multiple servers, nodes, or hosts. Performing RAN real-time functions on the RAN side (in distributed units (DU) 104) and non-real-time functions centrally (in a central unit (CU) 108) is possible, for example, by applying a cloud RAN architecture.

[0029] Furthermore, please understand that the division of roles between core network operation and access node operation may differ from, or may not exist at all, LTE. Other technological advancements that will change network construction and management methods, such as big data and all-IP, are also possible. 5G (or New Radio (NR)) networks may be designed to support multiple layers, and MEC servers may be placed between the core and access nodes. Please understand that MEC can also be applied to 4G networks.

[0030] Furthermore, 5G can enhance or complement the coverage of 5G services by utilizing non-terrestrial communications, such as satellite communications, to provide services like backhauling. Anticipated use cases include providing continuity of service to machine-to-machine (M2M) and Internet of Things (IoT) devices, or to passengers in vehicles, and ensuring the service availability of critical communications and future rail / maritime / air communications. Satellite communications can utilize geostationary (GEO) satellite systems, but also low Earth orbit (LEO) satellite systems, particularly mega-satellite systems (systems with hundreds of (nano) satellites). At least one satellite 106 of a mega-satellite system can cover multiple satellite-enabled network entities forming a ground cell. The ground cell is formed via ground relay nodes 104, or by gNBs located on the ground or satellite.

[0031] 6G networks are expected to adopt flexible, decentralized and / or distributed computing systems and architectures, ubiquitous computing, local spectrum licensing, spectrum sharing, infrastructure sharing, and intelligent, automated management supported by mobile edge computing, artificial intelligence, short packet communications, and blockchain technology. Key features of 6G include intelligent connectivity management and control, programmability, integrated sensing and communications, low energy consumption, reliable infrastructure, scalability, and affordability. In addition to these, 6G targets new use cases ranging from integrating localization and sensing capabilities into system design to unifying user experiences across the physical and digital worlds.

[0032] The system described is only one example of a wireless access system, and it will be apparent to those skilled in the art that in practice, the system may include multiple access nodes, user equipment may access multiple wireless cells, and the system may include other devices such as physical layer relay nodes or other network elements. At least one of the access nodes may be a home eNodeB or a home gNodeB.

[0033] Furthermore, an access node can also be divided into a radio transceiver (TRX), i.e., a radio unit (RU) including a transmitter (Tx) and a receiver (Rx), one or more distributed units (DUs) that can be used for so-called Layer 1 (L1) processing and real-time Layer 2 (L2) processing, and a central unit (CU) (also called a centralized unit) that can be used for non-real-time L2 and Layer 3 (L3) processing. For example, a CU can be connected to one or more DUs by using an F1 interface. Such a division allows for the centralization of CUs relative to cell sites and DUs, while DUs can be more distributed and may even remain at cell sites. The CU and DU together are sometimes referred to as a baseband or baseband unit (BBU). The CU and DU may also be included in a radio access point (RAP).

[0034] A CU may be defined as a logical node that hosts higher-layer protocols such as the access node's Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and / or Packet Data Convergence Protocol (PDCP). A DU may be defined as a logical node that hosts the access node's Radio Link Control (RLC), Medium Access Control (MAC), and / or Physical (PHY) layer. The operation of the DU may be controlled at least partially by the CU. A CU may include a control plane (CU-CP), which may be defined as a logical node that hosts the access node's RRC and the control plane portion of the CU's PDCP protocol. A CU may further include a user plane (CU-UP), which can be defined as a logical node that hosts the user plane portion of the CU's PDCP and SDAP protocols for the access node.

[0035] Cloud computing platforms can also be used to run CUs and / or DUs. CUs may run on cloud computing platforms, sometimes referred to as virtualized CUs (vCUs). In addition to vCUs, there may also be virtualized DUs (vDUs) running on cloud computing platforms. Furthermore, DUs may utilize so-called bare-metal solutions, such as application-specific integrated circuits (ASICs) or customer-specific standard product (CSSP) system-on-chip (SoC) solutions. It should also be understood that the distribution of work may differ between the aforementioned access node units, or between different core network operations and access node operations.

[0036] Furthermore, within the geographical area of ​​a wireless communication system, multiple different types of wireless cells may be provided, as well as multiple wireless cells. Wireless cells may be macrocells (or umbrella cells), which are large cells with diameters of up to tens of kilometers, or they may be small cells such as microcells, femtocells, or picocells. The access node(s) in Figure 1 can be of any type. A cellular wireless system can be implemented as a multi-layer network containing multiple types of wireless cells. In a multi-layer network, one access node may provide one type of wireless cell or wireless cell, so multiple access nodes may be required to provide such a network structure.

[0037] To meet the need to improve the deployment and performance of communication systems, the concept of "plug-and-play" access nodes may be introduced. Networks that can use "plug-and-play" access nodes may include home eNodeBs or home gNodeBs, as well as home node B gateways or HNB-GWs (not shown in Figure 1). HNB-GWs may be installed within the operator's network and can aggregate traffic from multiple home eNodeBs or home gNodeBs and return it to the core network.

[0038] UEs farther from the Transmit / Receive Point (TRP) may encounter greater propagation delays than other UEs closer to the TRP. Due to these greater propagation delays, uplink transmissions from more distant UEs may need to be pre-transmitted compared to uplink transmissions from closer UEs so that the uplink transmissions arrive at the TRP simultaneously. In this embodiment, the TRP may refer to any entity capable of transmitting and / or receiving radio signals, such as a network node or a remote radio head (RRH).

[0039] Figure 2 illustrates the concept of timing advance. Timing advance (TA) 200 is a negative offset at the UE between the start point of the received downlink (DL) frame 201 and the start point of the transmitted uplink (UL) frame 202. Timing advance can be used to account for propagation delay between the UE and the TRP. This offset can be used to ensure that the DL and UL frames are synchronized at the TRP (in the time domain). Thus, the UE can adjust uplink transmissions by pre-transmitting uplink symbols according to the amount of time defined by the timing advance.

[0040] TA adjustment can consist of two parts: 1) a part based on network signaling of TA adjustment to the UE (e.g., timing advance commands), and 2) autonomous UL transmission timing adjustment by the UE. In other words, once the UE is assigned a TA value by the network (e.g., via timing advance commands), the UE can track its DL timing and adjust its UL transmission timing to be within a set threshold.

[0041] The timing of UL transmission can be controlled by the network through timing advance commands (TACs) provided periodically in a closed-loop manner. Upon receiving a TAC from the network for a given timing advance group (TAG), the UE receives the received TAC and a fixed offset value N. TA,offset Based on this, the uplink timing of the physical uplink shared channel (PUSCH), physical uplink control channel (PUCCH), and / or sounding reference signal (SRS) transmission on the serving cell within the TAG can be adjusted.

[0042] Downlink, uplink, and sidelink transmissions may be organized into radio frames having a period of 10 ms, and a given radio frame includes 10 subframes of 1 ms. The uplink frame number i for transmissions from the UE starts before the start point of the corresponding downlink frame at the UE according to the timing advance, and this timing advance may be calculated, for example, as T TA =(N TA +N TA,offset )T c and may be calculated as such.

[0043] T TA is the calculated timing advance between the uplink and downlink applied by the UE. N TA is the timing advance value provided by the network (e.g., broadcast or provided by TAC). N TA,offset is a fixed offset value, but may vary according to different frequency bands and subcarrier intervals. T c is the basic time unit of NR and is, for example, 0.509 ns.

[0044] Currently, there are two ways to deliver TA adjustment to the UE: 1) via a random access response (RAR) or MsgB as part of the random access procedure, or 2) via a MAC control element (MAC CE).

[0045] In the first option (i.e., RAR or MsgB), the timing correction can be calculated by the network based on the random access preamble or MsgA received from the UE. The UE determines the timing advance value from two different MAC layer commands according to the situation. In the first uplink message after the random access procedure, the UE applies the timing advance value extracted from the RAR or MsgB. Thereafter, if the UE receives a timing advance MAC CE, the UE can apply the timing advance value extracted from the timing advance MAC CE.

[0046] In the second option (i.e., MAC CE), TA estimation is performed over the network based on one or more reference signals, such as demodulated reference signals (DMRS) or SRS, transmitted from the UE. As described above, the UE can adjust the UL transmit timing based on RAR during the random access procedure. Once the initial attach is complete, the UE can adjust the UL transmit based on the MAC CE timing advance. The timing advance command field may be, for example, 6 bits, which corresponds to -32 to 32T in actual timing. c This means a total of 64 stages up to T c If the value is 0.509 ns, the physical timing range is -16.3 μs to 16.3 μs with a subcarrier spacing of 15 kHz.

[0047] A TAG is composed of RRCs and may include a group of serving cells that can use the same timing reference cells and the same timing advance values ​​for cells in which a UL is composed. A TAG that includes a special cell (SpCell) of a MAC entity is called a primary timing advance group (PTAG), and the term secondary timing advance group (STAG) refers to other TAGs.

[0048] A parameter called timeAlignmentTimer is set via RRC (for each TAG), which controls the time at which a MAC entity considers the serving cells belonging to the associated TAG to be uplink time-aligned.

[0049] Receives timing advance command MAC CE, N TA If the designated TAG is maintained, the MAC entity can apply timing advance commands for the designated TAG and start or restart the timeAlignmentTimer associated with the designated TAG.

[0050] When a timing advance command is received in a RAR for a serving cell belonging to a TAG, or in a MsgB for a SpCell, and the random access preamble is not selected by the MAC entity from among the competition-based random access preambles, the MAC entity may apply the timing advance command for this TAG and start or restart the timeAlignmentTimer associated with this TAG.

[0051] If the timeAlignmentTimer associated with this TAG is not running, the MAC entity can apply a timing advance command for this TAG to start the timeAlignmentTimer associated with this TAG. If the conflict resolution is deemed unsuccessful, or if the conflict resolution is deemed successful for the System Information (SI) request, the MAC entity may stop the timeAlignmentTimer associated with this TAG after sending a Hybrid Automatic Retransmission Request (HARQ) feedback for the MAC Protocol Data Unit (PDU) containing the UE Conflict Resolution Identity MAC CE.

[0052] Otherwise, the MAC entity may ignore the timing advance command received in the RAR message.

[0053] When an absolute timing advance command is received in response to a MsgA transmission containing a Cell Radio Network Temporary Identifier (C-RNTI) MAC CE, the MAC entity can apply the timing advance command to the PTAG and start or restart the timeAlignmentTimer associated with the PTAG.

[0054] When a timeAlignmentTimer expires, and if a timeAlignmentTimer is associated with a PTAG, the MAC entity flushes all HARQ buffers for all serving cells, notifies the RRC to release PUCCH for all serving cells (if configured), notifies the RRC to release SRS for all serving cells (if configured), clears configured downlink and uplink assignments, clears PUSCH resources for semi-persistent channel status information (CSI) reporting, deems all running timeAlignmentTimers expired, and N for all TAGs TA It may be maintained. Here, flushing the HARQ buffer may mean emptying the HARQ buffer. The UE may consist of multiple HARQ processes, each HARQ process having or associated with a buffer. This HARQ buffer can be used to buffer transport blocks (TBs) (or packets) corresponding to the HARQ processes, for example, to allow retransmission of this TB at the request of the gNB if the gNB failed to receive the initial transmission correctly.

[0055] Otherwise, if timeAlignmentTimer is associated with STAG, for all serving cells belonging to this TAG, when timeAlignmentTimer expires, the MAC entity will notify RRC to flush all HARQ buffers, release PUCCH (if configured), release SRS (if configured), clear configured downlink and configured uplink assignments, clear any PUSCH resources for semi-persistent CSI reporting, and N of this TAG TA It is possible to maintain and perform.

[0056] If a MAC entity stops uplink transmitting to a secondary cell (S cell) due to exceeding the maximum uplink transmission timing difference between the TAGs of the MAC entity, or the maximum uplink transmission timing difference between the TAGs of any MAC entity in the UE, the MAC entity may be considered to have expired the timeAlignmentTimer associated with the S cell.

[0057] A MAC entity cannot perform uplink transmissions on a serving cell, except for random access preambles and MsgA transmissions, if the timeAlignmentTimer associated with the TAG to which the serving cell belongs is not functioning. Furthermore, if the timeAlignmentTimer associated with the PTAG is not functioning, a MAC entity cannot perform uplink transmissions on any serving cell, except for random access preambles and MsgA transmissions on a SpCell.

[0058] Starting with NR Release 18, simultaneous (or parallel) UL transmission schemes may be specified that allow for non-coordinated UL transmissions (e.g., PUCCH / PUSCH, PUCCH / PUCCH, and other UL overlapping channels) expected in multi-DCI multi-TRP operation, taking into account capacity and reliability considerations (e.g., repeated PUCCH, repeated PUSCH). DCI stands for Downlink Control Information. Simultaneous UL transmission may include allowing simultaneous or parallel PUCCH / PUSCH and PUSCH / PUCCH / SRS transmissions from two or more UE antenna panels (e.g., using different UL beams on FR2). Multi-TRP operation can support two or more TRPs.

[0059] Figure 3 shows simultaneous (or parallel) multi-panel UL transmission for multi-TRP operation. UE300 performs a first uplink transmission to the first TRP 304-1 via the first uplink beam 311. UE300 performs a second uplink transmission to the second TRP 304-2 via the second uplink beam 312, with the first and second uplink transmissions overlapping at least partially in time. It should also be noted that two or more uplink transmissions may be transmitted simultaneously to two or more TRPs. The first and second uplink transmissions may be transmitted from different UE antenna panels. For example, the first uplink transmission may be transmitted from the first antenna panel of UE300, and the second uplink transmission may be transmitted from the second antenna panel of UE300. The first TRP 304-1 and the second TRP 304-2 may belong to a single access node 304 (e.g., gNB) or to different access nodes (e.g., multiple gNBs). UE300 in Figure 3 may correspond to UE100 in Figure 1. Furthermore, access node 304 in Figure 3 may correspond to access node 104 in Figure 1.

[0060] In this specification, an uplink (UL) beam may also be referred to as spatial relation information, (separate) UL transmit configuration indicator (TCI) status, joint or common TCI status, spatial filter, power control information (or power control parameter set), antenna panel, or panel identifier (ID). In other words, these terms may be used interchangeably in this specification. Furthermore, a TRP may be identified by at least one of the following: SRS resource set, beam fault detection reference signal (BFD-RS) set, subset or set of UL beams, control resource set pool index (CORESETPoolIndex) (if set), and / or physical cell identifier (PCI). Furthermore, a given UE antenna panel may be identified by a panel ID. Alternatively or additionally, a given antenna panel may be identified or associated by at least one (DL) reference signal or by a UL beam.

[0061] NR Release 18 aims to include two TAs in both intra-cell and inter-cell multi-DCI multi-TRP operation. This feature may be referred to as multi-TA enhancement or two-TA enhancement. However, this feature may affect existing or legacy procedures.

[0062] In multi-DCI, there may be multiple physical downlink control channels (PDCCHs), each scheduling a PDSCH or UL transmission, and each PDSCH or UL transmission is transmitted from or to a separate TRP, along with a higher-layer parameter coresetPoolIndex that identifies a given TRP. Multi-DCI may be better suited to non-ideal backhaul (although it can also be used for ideal backhaul).

[0063] In contrast, with a single DCI, multiple TRP DL / UL transmissions or repetitive operations are scheduled within a single DCI. A single DCI may be more suitable for ideal backhaul configurations.

[0064] Several exemplary embodiments relate to time alignment operations and procedures and provide solutions that take into account the impact of introducing multi-TA enhancements to multi-TRP operations.

[0065] The following describes exemplary embodiments using the principles and terminology of NR technology, without being limited to NR communication systems.

[0066] In exemplary embodiments, operations and procedures related to timeAlignmentTimer that take into account multi-TRP multi-TA operation can be defined. For example, the operation of whether or not to flush the HARQ buffer of one or more cells is defined in this embodiment.

[0067] In some exemplary embodiments, a UE supporting multi-DCI-based multi-TRP operation (inter-cell or intra-cell) may consist of at least two TAGs per cell, each TAG corresponding to a TRP, PCI, or CORESETPoolIndex, and the TAGs are applicable to one or more (serving) cells (a prerequisite for the UE to support multi-TA operation). Here, the term “cell” may refer to a wireless cell.

[0068] The UE can assume a separate time alignment timer (timeAlignmentTimer) for each TRP / PCI / CORESETPoolIndex, taking the following points into consideration.

[0069] In an exemplary embodiment, if there are at least two primary TAGs (which may be associated with at least one identical serving cell or different cells), and the time alignment timers of one or both primary TAGs, each corresponding to a TRP / PCI / CORESETPoolIndex, expire, the UE may flush the HARQ buffers of all serving cells configured for the UE (and active) if the time alignment timers of the primary TAGs expire (substantially) simultaneously or at different times but within a predefined or set period (e.g., within a certain threshold). To achieve this, one method is for the UE to have a dedicated timer that is triggered each time one of the time alignment timers expires, and if the second time alignment timer expires before the dedicated timer expires, the UE flushes the HARQ buffers of all its serving cells and stops the dedicated timer. The dedicated timer is also referred to herein as the third timer. Otherwise, if the second time alignment timer does not expire before the dedicated timer expires, the UE may not flush any of the cell's HARQ buffers. This is shown in Figure 4.

[0070] Figure 4 shows a flowchart illustrating an exemplary embodiment of a method performed by a user device or other device, or a device including a user device, or a device included in a user device.

[0071] Referring to Figure 4, in block 401, the device detects that the first time alignment timer, one of at least two time alignment timers, has expired. The first time alignment timer is associated with the first PTAG.

[0072] In block 402, a dedicated timer is started in response to the expiration of the first time alignment timer. The dedicated timer is also referred to herein as the third timer. The third timer may correspond to a predetermined period (threshold), that is, the third timer may be configured to expire when it reaches a time value corresponding to the predetermined period.

[0073] In block 404, if the second time alignment timer associated with the second PTAG expires before the dedicated timer (third timer) expires (Yes in 403), that is, if the second time alignment timer expires within a predetermined period relative to the expiration of the first time alignment timer, the device flushes the HARQ buffer(s) corresponding to multiple cells. Multiple cells may refer to all serving cells configured (and active) for this device.

[0074] Alternatively, in block 405, if the second time alignment timer does not expire before the dedicated timer (third timer) expires (No in 403), that is, if the second time alignment timer does not expire within a predetermined period relative to the expiration of the first time alignment timer, the device does not flush any cell's HARQ buffer(s).

[0075] In other words, the decision of whether or not to flush the HARQ buffer can be made based on the expiration of the first time alignment timer in relation to the expiration of the second time alignment timer, that is, based on whether or not the second time alignment timer expires before the dedicated timer (third timer) expires.

[0076] Here, the terms "first time alignment timer" and "second time alignment timer" are used to distinguish between timers and do not necessarily refer to a specific order or identification number of the timers.

[0077] Such use of the relative expiration of one time alignment timer to other time alignment timers is beneficial when considering the following: If two time alignment timers (e.g., each corresponding to a TRP) expire within a short period, there may not be enough time to acquire and adjust the first TA before the second time alignment timer expires. This should be seen as the flushing of all HARQ buffers occurring because there is no available synchronous UL. On the other hand, if the second time alignment timer expires a predetermined time after the expiration of the first time alignment timer, there is enough time to acquire and adjust the first TA (before the second time alignment timer expires). As a result, there is no need to flush the HARQ buffers because there is at least one available synchronous UL. In this case, a HARQ retransmission to a TRP different from the TRP for the initial transmission is assumed.

[0078] Figure 5 shows an example corresponding to the exemplary embodiment of Figure 4, in which the UE is set (e.g., via RRC) with a threshold (a predetermined period) related to the expiration of two time alignment timers (time alignment timer 0 and time alignment timer 1). In this embodiment, time alignment timers 1 and 0 expire within a period 500 shorter than the threshold (501, 502), and since these timers correspond to the primary TAG, the UE flushes the HARQ buffer for all serving cells set (and active) for the UE. Time alignment timer 1 may also be referred to herein as the first time alignment timer, and time alignment timer 0 may also be referred to herein as the second time alignment timer. TAG#1 may also be referred to herein as the first timing advance group, and TAG#0 may also be referred to herein as the second timing advance group.

[0079] Figure 5 shows that time alignment timer 1 expires before time alignment timer 0, but time alignment timer 0 may also expire before time alignment timer 1. In this case, if time alignment timer 1 expires within a shorter period than the threshold after time alignment timer 0 expires, and these timers correspond to the primary TAG, the UE may flush the HARQ buffers of all serving cells configured (and active) for the UE. In other words, the relative expiration of time alignment timers can be used to trigger a flush of the HARQ buffers for all serving cells, regardless of the specific order in which the time alignment timers expire.

[0080] In an exemplary embodiment, if there are at least two secondary TAGs (which may be associated with at least one identical serving cell or different cells), the UE can flush the HARQ buffers for these TAGs if the time alignment timers for both secondary TAGs corresponding to TRP / PCI / CORESETPoolIndex expire, either (substantially) simultaneously or at different times but within a predetermined or set period (i.e., within a certain threshold). To achieve this, a similar method to that described for the primary TAG can be employed here, as shown in Figure 6.

[0081] Figure 6 shows a flowchart illustrating an exemplary embodiment of a method performed by a user device or other device, a device including a user device, or a device included in a user device.

[0082] Referring to Figure 6, in block 601, the device detects that the first time alignment timer, of at least two time alignment timers, has expired. The first time alignment timer is associated with the first STAG.

[0083] In block 602, a dedicated timer is started in response to the expiration of the first time alignment timer. The dedicated timer may also be referred to as the third timer in this specification. The third timer may correspond to a predetermined period (threshold), that is, the third timer may be set to expire when it reaches a time value corresponding to the predetermined period.

[0084] In block 604, if the second time alignment timer associated with the second STAG expires before the dedicated timer (third timer) expires (Yes in 603), that is, if the second time alignment timer expires within a predetermined period relative to the expiration of the first time alignment timer, the device flushes the HARQ buffer(s) corresponding to the first STAG and the second STAG.

[0085] Alternatively, in block 605, if the second time alignment timer does not expire before the dedicated timer (third timer) expires (as indicated by "No" in 603), that is, if the second time alignment timer does not expire within a predetermined period relative to the expiration of the first time alignment timer, the device does not flush the HARQ buffer(s) of STAG.

[0086] In an exemplary embodiment (see Figure 7), if there are two TAGs, each corresponding to a TRP / PCI / CORESETPoolIndex, and the time alignment timer for the first TAG or the first TRP expires and the UE does not receive a TAC corresponding to the second TAG or TRP before the time alignment timer for the second TAG expires, the UE may flush the HARQ buffers of all serving cells configured (and active) for the UE, if the TAG is a primary TAG. If the two TAGs are secondary TAGs, the UE may flush the HARQ buffers of the cells in these TAGs. Otherwise, if the time alignment timer for the first TAG or the first TRP expires and the UE receives a TAC corresponding to the second TAG before the time alignment timer for the second TAG expires, the UE does not flush the HARQ buffers of any cells, if the TAG is a primary TAG. If the two TAGs are secondary TAGs, the UE does not flush the HARQ buffers of any cells in these TAGs. Reception of a TAC may correspond to the reception of the last symbol of a physical downlink control channel (PDCCH) that schedules a physical downlink shared channel (PDSCH) carrying a TAC, or the last symbol of a PDSCH carrying a TAC (including a RAR), or the first or last symbol of a PUCCH / PUSCH transmitting a HARQ acknowledgment (HARQ-ACK) corresponding to a PDSCH containing a TAC, or to a certain period before or after the reception or transmission of such PDCCH, PDSCH, or PUCCH / PUSCH.

[0087] Figure 7 shows a flowchart illustrating an exemplary embodiment of a method performed by a user device or other device, a device including a user device, or a device included in a user device.

[0088] Referring to Figure 7, in block 701, the device detects that the first time alignment timer, of at least two time alignment timers, has expired. The first time alignment timer is associated with the first TAG.

[0089] In block 703, if no TAC corresponding to the second TAG is received after the first time alignment timer expires and before the second time alignment timer associated with the second TAG expires (702, "No"), the device flushes one or more HARQ buffers. If the first and second TAGs are PTAGs, the device may flush the HARQ buffer(s) of all (and active) serving cells configured for the device. If the first and second TAGs are STAGs, the device may flush the HARQ buffers of the cells within the first and second TAGs.

[0090] Alternatively, in block 704, if a TAC corresponding to the second TAG is received before the second time alignment timer associated with the second TAG expires (in 702, "Yes"), the device does not flush one or more HARQ buffers. If the first and second TAGs are primary TAGs, the device does not flush any HARQ buffers for any cells. If the first and second TAGs are secondary TAGs, the device does not flush any HARQ buffers for any cells within those TAGs.

[0091] In an exemplary embodiment (see Figure 8), if there are two TAGs, each corresponding to a TRP / PCI / CORESETPoolIndex, and the time alignment timer for the first TAG or the first TRP expires and the UE does not receive a PDCCH instruction corresponding to the second TAG or TRP before the time alignment timer for the second TAG expires, the UE may flush the HARQ buffers of all serving cells configured (and active) for the UE, provided the TAG is a primary TAG. If the two TAGs are secondary TAGs, the UE may flush the HARQ buffers of the cells in these TAGs. Otherwise, if the time alignment timer for the first TAG or the first TRP expires and the UE receives a PDCCH instruction corresponding to the second TAG before the time alignment timer for the second TAG expires, the UE does not flush the HARQ buffers of any cells, provided the TAG is a primary TAG. If the two TAGs are secondary TAGs, the UE does not flush the HARQ buffers of any cells within those TAGs. The reference point for receiving the PDCCH instruction in this case may be the last symbol of the PDCCH instruction, the last symbol of the physical random access channel (PRACH), or a random access procedure message (which may be a two-step or four-step random access procedure) sent from or received by the UE (triggered by the PDCCH instruction), or a certain period of time after the transmission or reception of these messages / signals.

[0092] Figure 8 shows a flowchart illustrating an exemplary embodiment of a method performed by a device such as user equipment, or by a device including user equipment, or by a device included in user equipment.

[0093] Referring to Figure 8, in block 801, the device detects that the first time alignment timer, of at least two time alignment timers, has expired. The first time alignment timer is associated with the first TAG.

[0094] In block 803, if no PDCCH instruction corresponding to the second TAG is received after the first time alignment timer expires but before the second time alignment timer associated with the second TAG expires (in 802, "No"), the device flushes one or more HARQ buffers. If the first and second TAGs are PTAGs, the device may flush the HARQ buffers of all serving cells configured (and active) for the device. If the first and second TAGs are STAGs, the device may flush the HARQ buffers of the cells in the first and second TAGs.

[0095] Alternatively, if in block 804 a PDCCH instruction corresponding to the second TAG is received before the second time alignment timer associated with the second TAG expires (Yes in 802), the device does not flush one or more HARQ buffers. If the first and second TAGs are primary TAGs, the device does not flush any HARQ buffers in any cells. If the first and second TAGs are secondary TAGs, the device does not flush any HARQ buffers in any cells within those TAGs.

[0096] In an exemplary embodiment, if a cell has a first TAG whose time alignment timer has expired and a second TAG whose time alignment timer has not expired, the UE may be configured not to flush the HARQ buffer for this cell, but to flush the HARQ buffer associated with the TAG associated with the expired time alignment timer. For example, if the expired time alignment timer is associated with the first TAG, the UE may flush the HARQ buffer associated with the first TAG, but not with the HARQ buffer associated with the second TAG. This is shown in Figure 9. This makes it possible to retransmit the transport block (TB) whose corresponding time alignment timer has not expired to the TRP.

[0097] Figure 9 shows a flowchart illustrating an exemplary embodiment of a method performed by a user device or other device, or a device including a user device, or a device included in a user device.

[0098] Referring to Figure 9, in block 901, the device detects that the first time alignment timer, of at least two time alignment timers, has expired. The first time alignment timer is associated with the first TAG.

[0099] In block 903, if the second time alignment timer associated with the second TAG has not expired (No in 902) and the first time alignment timer has expired, the device flushes the HARQ buffer(s) of the first TAG (but does not flush the HARQ buffer of the second TAG).

[0100] Alternatively, if both the second time alignment timer and the first time alignment timer have expired in block 904 (Yes in 902), the device flushes the HARQ buffer(s) of the first and second TAGs.

[0101] In an exemplary embodiment, if a cell consists of (or belongs to) a single TAG whose time alignment timer has expired, the UE may flush all HARQ buffers for that cell. If this TAG is a primary TAG, i.e., if the cell is a special cell that supports at least contention-based random access, the UE may flush the HARQ buffers for all serving cells configured (and active) for the UE. This is shown in Figure 10.

[0102] Figure 10 shows a flowchart illustrating an exemplary embodiment of a method performed by a user device or other device, or a device including a user device, or a device included in a user device.

[0103] Referring to Figure 10, in block 1001, the device detects that the first time alignment timer of at least two time alignment timers has expired. The first time alignment timer is associated with the first TAG. In an exemplary embodiment, the cell consists of a single TAG (i.e., the first TAG).

[0104] In block 1003, if the first TAG is a PTAG (Yes in 1002), i.e., if the cell is a special cell, the device flushes the HARQ buffer(s) of all (and active) serving cells configured for the device.

[0105] Alternatively, in block 1004, if the first TAG is not a PTAG ("No" in 1002), the device flushes the HARQ buffer(s) of the cell associated with the first TAG. However, if the first TAG is not a PTAG, the device does not flush the HARQ buffer(s) of the other cells.

[0106] In other words, the device may flush the HARQ buffer(s) of one or more cells depending on whether the first TAG is a PTAG, and one or more cells include at least one cell consisting of a single TAG (i.e., the first TAG).

[0107] In an exemplary embodiment, if the UE does not support HARQ retransmission via a TRP different from the TRP used for the initial transmission (to allow UL retransmission to the same TRP used for the UL transmission), the following further considerations may be defined. In an exemplary embodiment, for a cell consisting of two TAGs, each TAG corresponds to or is associated with a TRP / PCI / CORESETPoolIndex, and the HARQ buffer for this cell can be divided into two groups, each corresponding to a TAG or TRP / PCI / CORESETPoolIndex. Note that a cell may consist of only one TAG. In this case, this TAG corresponds to or is associated with a default CORESETPoolIndex, such as CORESETPoolIndex0. When the time alignment timer for one TAG or CORESETPoolIndex expires, the HARQ buffer corresponding to this TAG or CORESETPoolIndex may be flushed for each cell consisting of this TAG or CORESETPoolIndex. This is shown in Figure 11.

[0108] Figure 11 shows a flowchart illustrating an exemplary embodiment of a method performed by a user device or other device, or a device including a user device, or a device included in a user device.

[0109] In the exemplary embodiment of this example, the multiple HARQ buffers of the cell are divided into at least two groups.

[0110] Referring to Figure 11, in block 1101, the device detects that the first time alignment timer of at least two time alignment timers has expired. The first time alignment timer may be associated with at least one of the following: a first timing advance group, a first transmit / receive point, a first cell identity, and / or a first control resource set pool index. Here, the term "cell identity" may refer, for example, to a physical cell identity (PCI).

[0111] In block 1102, in response to the expiration of the first time alignment timer, the device flushes the first group of at least two groups of HARQ buffers. The first group may be associated with at least one of the first timing advance group, the first transmit / receive point, the first cell identity, and / or the first control resource set pool index associated with the expired first time alignment timer.

[0112] In block 1103, the device detects that the second time alignment timer of at least two time alignment timers has expired. The second time alignment timer may be associated with at least one of the following: a second timing advance group, a second transmit / receive point, a second cell identity, and / or a second control resource set pool index.

[0113] In block 1104, in response to the expiration of the second time alignment timer, the device flushes the second group of at least two groups of HARQ buffers. The second group may be associated with at least one of the second timing advance group, the second transmit / receive point, the second cell identity, and / or the second control resource set pool index associated with the expired second time alignment timer.

[0114] Figure 12 shows an example corresponding to the exemplary embodiment of Figure 11, in which the UE is configured (e.g., via RRC) such that the cell's HARQ buffer is divided into two groups, namely group #0 and group #1, each corresponding to a TAG or CORESETPoolIndex. In this embodiment, when time alignment timer 1 for TAG #1 expires (1201), the UE flushes the HARQ buffer corresponding to TAG #1 (1203). When time alignment timer 0 for TAG #0 expires (1202), the UE flushes the HARQ buffer corresponding to TAG #0 (1204). Time alignment timer 1 may also be referred to herein as the first time alignment timer, and time alignment timer 0 may also be referred to herein as the second time alignment timer. TAG #1 may also be referred to herein as the first timing advance group, and TAG #0 may also be referred to herein as the second timing advance group.

[0115] Figure 13 shows a flowchart illustrating an exemplary embodiment of a method performed by a user device or other device, or a device including a user device, or a device included in a user device.

[0116] Referring to Figure 13, in block 1301, the device determines whether to flush one or more Hybrid Automatic Retransmission Request (HARQ) buffers based on the expiration of at least one of at least two time alignment timers. At least two time alignment timers may be set on the device by a network (e.g., gNB).

[0117] At least two time alignment timers may comprise at least a first time alignment timer and a second time alignment timer. The first time alignment timer of the at least two time alignment timers may be associated with a first timing advance group, and the second time alignment timer of the at least two time alignment timers may be associated with a second timing advance group. The first and second timing advance groups may be, for example, a primary timing advance group and a secondary timing advance group.

[0118] The first timing advance group may correspond to at least one of the first transmit / receive point, the first cell identity, and / or the first control resource set pool index. The second timing advance group may correspond to at least one of the second transmit / receive point, the second cell identity, and / or the second control resource set pool index.

[0119] As used herein, “at least one of the following, <list of two or more elements>,” “at least one of the <list of two or more elements>,” and similar expressions in which lists of two or more elements are joined by “and” or “or” mean at least one of the elements, or at least two or more of the elements, or at least all of the elements.

[0120] Note that some exemplary embodiments may also apply to operations other than, for example, flushing the HARQ buffer. For example, the following operations:

[0121] 1) If configured, notify the RRC to release PUCCH for at least some serving cells. Assuming there is a relationship between PUCCH and TAG or CORESETPoolIndex / PCI / TRP, when the TAG's time alignment timer expires, the UE can release the PUCCH corresponding to or associated with that TAG or CORESETPoolIndex / PCI / TRP.

[0122] 2) If configured, notify the RRC to release SRS for all serving cells. Assuming there is a relationship between an SRS resource or resource set and a TAG or CORESETPoolIndex / PCI / TRP, when the TAG's time alignment timer expires, the UE can release the SRS corresponding to or associated with that TAG or CORESETPoolIndex / PCI / TRP.

[0123] 3) Clear configured downlink allocations and configured uplink grants. Assuming there is a relationship between configured DL allocations / configured grants or their respective resources and a TAG or CORESETPoolIndex / PCI / TRP, when the TAG's time alignment timer expires, the UE can clear the configured DL allocations / configured grants corresponding to or associated with that TAG or CORESETPoolIndex / PCI / TRP.

[0124] 4) Clearing PUSCH resources for semi-persistent CSI reporting. Assuming there is a relationship between a PUSCH resource (for semi-persistent CSI) and a TAG or CORESETPoolIndex / PCI / TRP, when the TAG's time alignment timer expires, the UE can clear the PUSCH resource for semi-persistent CSI corresponding to or associated with that TAG or CORESETPoolIndex / PCI / TRP.

[0125] Note that the conditions for which the above applies to a cell may be similar to those defined for flushing the HARQ buffer.

[0126] The blocks and related functions described above using Figures 4, 6-11, and 13 are not necessarily in absolute chronological order; some may be executed simultaneously, or in an order different from that described. Other functions may be executed between or within them, transmitting other information and / or applying other rules. Some or parts of the blocks may be omitted or replaced with corresponding blocks or parts of blocks.

[0127] Figure 14 shows an exemplary embodiment of device 1400, which may be a user device, a device containing a user device, or a device included in a user device. The user device may correspond to one of the user devices (100, 102) in Figure 1. The user device may also be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal, terminal equipment, or user equipment (UE).

[0128] The device 1400 comprises at least one processor 1410. The at least one processor 1410 interprets computer program instructions and processes data. The at least one processor 1410 may comprise one or more programmable processors. The at least one processor 1410 may comprise programmable hardware having embedded firmware, and may optionally or additionally comprise one or more application-specific integrated circuits (ASICs).

[0129] At least one processor 1410 is connected to at least one memory 1420. At least one processor is configured to read and write data to and from at least one memory 1420. At least one memory 1420 may comprise one or more memory units. Memory units may be volatile or non-volatile. Note that in some exemplary embodiments, there may be one or more non-volatile memory units and one or more volatile memory units, or one or more non-volatile memory units, or one or more volatile memory units. Volatile memory is, for example, random access memory (RAM), dynamic random access memory (DRAM), or synchronous dynamic random access memory (SDRAM). Non-volatile memory is, for example, read-only memory (ROM), programmable read-only memory (PROM), electronically erasable programmable read-only memory (EEPROM), flash® memory, optical memory, or magnetic memory. In general, memory is sometimes referred to as a non-temporary computer-readable medium. At least one memory 1420 stores computer-readable instructions to be executed by at least one processor 1410 to perform one or more of the exemplary embodiments described above. For example, non-volatile memory stores computer-readable instructions, and at least one processor 1410 executes the instructions using volatile memory for temporary storage of data and / or instructions.

[0130] Computer-readable instructions may be pre-stored in at least one memory 1420, or alternatively or additionally, received by the device via electromagnetic carrier signals and / or copied from a physical entity such as a computer program product. The execution of computer-readable instructions by at least one processor 1410 causes the device 1400 to perform one or more of the exemplary embodiments described above. That is, at least one processor and at least one memory storing instructions can provide means for providing or performing any of the methods and / or blocks described above.

[0131] In the context of this specification, “memory” or “computer-readable medium” or “multiple computer-readable mediums” may be any non-temporary medium or multiple mediums or means that can store, store, communicate, propagate, or carry instructions for use by or in connection with an instruction execution system, apparatus, or device such as a computer. The term “non-temporary” as used herein is used to define the medium itself (i.e., tangible and not signaling) and not to define the persistence of data storage (e.g., RAM vs. ROM).

[0132] The device 1400 further comprises or is connected to an input unit 1430. The input unit 1430 may have one or more interfaces for receiving input. One or more interfaces may include, for example, one or more temperature sensors, motion sensors and / or compass sensors, one or more cameras, one or more accelerometers, one or more microphones, one or more buttons, and / or one or more touch detection units. Furthermore, the input unit 1430 may have interfaces to which external devices can be connected.

[0133] The device 1400 may also include an output unit 1440. The output unit may include, or be connected to, one or more displays capable of rendering visual content, such as light-emitting diode (LED) displays, liquid crystal displays (LCDs), and / or liquid crystal on silicon (LCoS) displays. The output unit 1440 may further include one or more audio output units. One or more audio output units may be, for example, speakers.

[0134] The device 1400 further comprises a connection unit 1450. The connection unit 1450 enables wireless connectivity to one or more external devices. The connection unit 1450 comprises at least one transmitter and at least one receiver, which may be integrated with the device 1400 or to which the device 1400 may be connected. The at least one transmitter comprises at least one transmitting antenna, and the at least one receiver comprises at least one receiving antenna. The connection unit 1450 may comprise an integrated circuit or set of integrated circuits that provide wireless communication functionality to the device 1400. Alternatively, the wireless connection unit may be a hardwired application-specific integrated circuit (ASIC). The connection unit 1450 may comprise one or more components, such as a power amplifier, a digital front end (DFE), an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), a frequency converter, a modulator, a demodulator, and / or an encoder / decoder circuit, which are controlled by a corresponding control unit.

[0135] It should be noted that the device 1400 may further include various components not shown in Figure 14. These various components may be hardware components and / or software components.

[0136] As used in this application, the term "circuit" may refer to one, more, or all of the following: a) a hardware-only circuit implementation (such as an implementation in analog and / or digital circuits only); b) a combination of hardware circuits and software, for example (where applicable), i) a combination of analog and / or digital hardware circuits(s) and software / firmware; ii) any part of a hardware processor(s) and software (including digital signal processors(s), software, and memory(s) that work together to enable a device such as a mobile phone to perform various functions); and c) a hardware circuit(s) and / or processor(s), such as a microprocessor(s) or a part of a microprocessor(s), that requires software (e.g., firmware) to operate, but may not exist when not required for operation.

[0137] This definition of circuit applies to all use of the term in this application, including in all claims. As a further example, in the use of this embodiment, the term circuit also includes not only a hardware circuit or processor (or more processors) or a part of a hardware circuit or processor and the implementation of software and / or firmware associated with it (or them). The term circuit also includes, for example, a baseband integrated circuit or processor integrated circuit for a portable device, or a similar integrated circuit in a server, cellular network device, or other computing or network device, where applicable to the elements of a particular claim.

[0138] The techniques and methods described herein can be implemented by various means. For example, these techniques can be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. In the case of hardware implementation, the device(s) of the exemplary embodiment may be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described in this embodiment, or a combination thereof. Firmware or software can be implemented through at least one chipset module (e.g., procedures, functions, etc.) that performs the functions in this embodiment. Software code can be stored in a memory unit and executed by the processor. The memory unit may be implemented within the processor or outside the processor. In the latter case, it can be communicated with the processor by various means as known in the art. Furthermore, the components of the system described herein may be rearranged and / or complemented by additional components to facilitate the achievement of various embodiments, etc., described herein, and these are not limited to the exact configuration shown in the given figures, as will be understood by those skilled in the art.

[0139] As technology advances, it will be apparent to those skilled in the art that the concept of the present invention can be implemented in a variety of ways. This embodiment is not limited to the exemplary embodiments described above and can be modified within the scope of the claims. Therefore, all words and expressions should be interpreted broadly and are intended to illustrate, rather than limit, the exemplary embodiments.

Claims

1. At least one processor, When executed by the aforementioned at least one processor, the device will have The determination of whether or not to flush the Hybrid Automatic Retransmission Request (HARQ) buffer based on the expiration of at least one of at least two time alignment timers, Of the at least two time alignment timers, the first time alignment timer is associated with the first timing advance group, and the second time alignment timer is associated with the second timing advance group. The HARQ buffer corresponds to the first timing advance group and the second timing advance group, and the first timing advance group and the second timing advance group are secondary timing advance groups, to be determined. A memory device that stores at least one instruction that causes the execution of a certain function, The command causes the device to flush the HARQ buffer in response to not receiving a timing advance command corresponding to the second timing advance group after the first time alignment timer has expired and before the second time alignment timer has expired. Device.

2. The first timing advance group corresponds to at least one of the first transmission / reception point, the first cell identity, or the first control resource set pool index. The second timing advance group corresponds to at least one of the second transmission / reception point, the second cell identity, or the second control resource set pool index. The apparatus according to claim 1.

3. The apparatus according to claim 1 or 2, wherein the apparatus comprises user equipment or is provided within user equipment.

4. The determination of whether or not to flush the Hybrid Automatic Retransmission Request (HARQ) buffer based on the expiration of at least one of at least two time alignment timers, Of the at least two time alignment timers, the first time alignment timer is associated with the first timing advance group, and the second time alignment timer is associated with the second timing advance group. The HARQ buffer corresponds to the first timing advance group and the second timing advance group, and the first timing advance group and the second timing advance group are secondary timing advance groups, and this is determined. After the first time alignment timer expires and before the second time alignment timer expires, in response to not receiving a timing advance command corresponding to the second timing advance group, the HARQ buffer is flushed. A method that includes this.

5. When performed by the device, the device determines whether or not to flush the Hybrid Automatic Retransmission Request (HARQ) buffer based on the expiration of at least one of the at least two time alignment timers, Of the at least two time alignment timers, the first time alignment timer is associated with the first timing advance group, and the second time alignment timer is associated with the second timing advance group. The HARQ buffer corresponds to the first timing advance group and the second timing advance group, and the first timing advance group and the second timing advance group are secondary timing advance groups, and this is determined. After the first time alignment timer expires and before the second time alignment timer expires, in response to not receiving a timing advance command corresponding to the second timing advance group, the HARQ buffer is flushed. A non-temporary computer-readable storage medium containing program instructions that cause at least the execution of a program.

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