Method and apparatus for managing drop timer for removing mismatch between valid times of multiple devices in wireless communication system

Abstract

The present disclosure relates to a method of performing an operation for a packet data convergence protocol (PDCP) entity of a user equipment (UE) in a wireless communication system. Specifically, the method comprises the following steps: establishing a PDCP entity; starting a drop timer for the PDCP entity at the reference time; receiving at least one PDCP service data unit (SDU) from an upper layer during a drop timer for the PDCP entity is running; and discarding the at least one PDCP SDU based on expiration of the discard timer for the PDCP entity.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a wireless communication system, and more particularly, to a method of managing a discard timer for removing a mismatch between valid times of a plurality of apparatuses in a wireless communication system and a device therefor. BACKGROUND

[0002] Introduction of new radio communication technology has resulted in an increase in the number of user equipments (UEs) to which a base station (BS) provides services in a prescribed resource region, and has also resulted in an increase in the amount of control information and data transmitted by the BS to the UEs. Since resources available for communication by the BS with the UEs are generally limited, new techniques are needed for the BS to efficiently receive / transmit uplink / downlink data and / or uplink / downlink control information with limited radio resources. In particular, in applications in which performance is critically dependent on delay / latency, overcoming delay or latency has become an important challenge. SUMMARY

[0003] TECHNICAL PROBLEM

[0004] Accordingly, an object of the disclosure is to provide a method of managing a discard timer for removing a mismatch between valid times of a plurality of apparatuses in a wireless communication system and a device therefor.

[0005] TECHNICAL SOLUTION

[0006] The object of the disclosure can be achieved by a method for performing an operation of a packet data convergence protocol (PDCP) entity of a user equipment (UE) in a wireless communication system, the method including the steps of establishing the PDCP entity; starting a discard timer for the PDCP entity at a reference time; receiving at least one PDCP service data unit (SDU) from an upper layer during the discard timer for the PDCP entity is running; and discarding the at least one PDCP SDU based on the discard timer for the PDCP entity expires.

[0007] Further, a user equipment (UE) in a wireless communication system is proposed, the UE including at least one transceiver; at least one processor; and at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform an operation of a packet data convergence protocol (PDCP) entity of the UE, the operation including establishing the PDCP entity; starting a discard timer for the PDCP entity at a reference time; receiving at least one PDCP service data unit (SDU) from an upper layer during the discard timer for the PDCP entity is running; and discarding the at least one PDCP SDU based on the discard timer for the PDCP entity expires.

[0008] Preferably, the step of establishing the PDCP entity includes receiving information about a discard timer for the PDCP entity.

[0009] Preferably, the discard timer for the PDCP entity is periodically started, and a length of the discard timer for the PDCP entity is less than or equal to a period of a start time of the discard timer for the PDCP entity.

[0010] Preferably, the PDCP entity is configured with two or more quality of service (QoS) flows, and the discard timer for the PDCP entity is configured for each of the two or more QoS flows.

[0011] Preferably, if any PDCP SDU is not received before an expiration of the discard timer for the PDCP entity, the PDCP entity increments a failure count value (FCV) by 1.

[0012] More specifically, if the FCV is greater than or equal to a threshold value, the PDCP entity transmits information related to a radio link failure to an upper layer.

[0013] Those skilled in the art will understand that the effects which can be achieved by the present disclosure are not limited to what has been particularly described hereinabove and other advantages of the present disclosure will be more clearly understood from the following detailed description.

[0014] Advantageous Effects

[0015] According to the present disclosure, when the valid time does not match between the binding device and the UE, the UE can prevent unnecessary transmission for outdated SDUs.

[0016] Effects obtainable from the present disclosure can not be limited to the above-mentioned effects and other unmentioned effects will be clearly understood from the following description by those having ordinary skill in the art. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure:

[0018] Figure 1 An example of a communication system 1 to which implementations of the present disclosure are applied is illustrated;

[0019] Figure 2 is a block diagram illustrating an example of a communication device that can perform a method according to the present disclosure;

[0020] Figure 3 An example of a frame structure in a 3GPP-based wireless communication system is illustrated;

[0021] Figure 4 An example of a protocol stack in a Third Generation Partnership Project (3GPP) based wireless communication system is illustrated;

[0022] Figure 5 An example of a data flow in a 3GPP New Radio (NR) system is illustrated;

[0023] Figure 6 Examples of PDSCH time domain resource allocation by PDCCH and examples of PUSCH time resource allocation by PDCCH are illustrated;

[0024] Figure 7 An example of physical layer processing at the transmitting side is illustrated;

[0025] Figure 8 An example of physical layer processing at the receiving side is illustrated;

[0026] Figure 9 An example of a mismatch between the validity times of two apparatuses is shown;

[0027] Figure 10 A first example of managing a discard timer according to the present disclosure is shown;

[0028] Figure 11 A second example of managing a discard timer according to the present disclosure is shown;

[0029] Figure 12 A third example of managing a discard timer according to the present disclosure is shown; and

[0030] Figure 13 A flowchart for managing a discard timer according to the present disclosure is shown. DETAILED DESCRIPTION

[0031] Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure, rather than to show the only embodiments in accordance with the present disclosure. The following detailed description includes specific details in order to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure can be practiced without such specific details.

[0032] The following techniques, apparatuses, and systems can be applied to various wireless multiple access systems. Examples of the multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and multi-carrier frequency division multiple access (MC-FDMA) systems. CDMA can be implemented by radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA can be implemented by radio technology such as global system for mobile communications (GSM), general packet radio service (GPRS), or enhanced data rates for GSM evolution (EDGE). OFDMA can be implemented by radio technology such as institute of electrical and electronics engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or evolved UTRA (E-UTRA). UTRA is part of a universal mobile telecommunication system (UMTS). A third generation partnership project (3GPP) long term evolution (LTE) is a part of an evolved UMTS (E-UMTS). 3GPP LTE employs OFDMA for DL and employs SC-FDMA for UL. LTE-Advanced (LTE-A) is a release of the 3GPP LTE.

[0033] For convenience of description, implementation modes of the disclosure are mainly described with respect to a 3GPP-based wireless communication system. However, technical features of the disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP-based wireless communication system, aspects of the disclosure that are not limited to the 3GPP-based wireless communication system are applicable to other mobile communication systems. For terms and technologies that are not specifically described among terms and technologies employed in the disclosure, reference can be made to wireless communication standard documents published before the disclosure. For example, reference can be made to the following documents.

[0034] 3GPP LTE

[0035] - 3GPP TS 36.211: Physical channels and modulation

[0036] - 3GPP TS 36.212: Multiplexing and channel coding

[0037] - 3GPP TS 36.213: Physical layer procedures

[0038] - 3GPP TS 36.214: Physical layer; Measurements

[0039] - 3GPP TS 36.300: Overall description

[0040] - 3GPP TS 36.304: User Equipment (UE) procedures in idle mode

[0041] - 3GPP TS 36.314: Layer 2 - Measurements

[0042] - 3GPP TS 36.321: Medium Access Control (MAC) protocol

[0043] - 3GPP TS 36.322: Radio Link Control (RLC) protocol

[0044] - 3GPP TS 36.323: Packet Data Convergence Protocol (PDCP)

[0045] - 3GPP TS 36.331: Radio Resource Control (RRC) protocol

[0046] 3GPP NR (e.g., 5G)

[0047] - 3GPP TS 38.211: Physical channels and modulation

[0048] - 3GPP TS 38.212: Multiplexing and channel coding

[0049] - 3GPP TS 38.213: Physical layer procedures for control

[0050] - 3GPP TS 38.214: Physical layer procedures for data

[0051] - 3GPP TS 38.215: Physical layer measurements

[0052] - 3GPP TS 38.300: Overall description

[0053] - 3GPP TS 38.304: User Equipment (UE) procedures in idle mode and in RRC inactive state

[0054] - 3GPP TS 38.321: Medium Access Control (MAC) protocol

[0055] - 3GPP TS 38.322: Radio Link Control (RLC) protocol

[0056] - 3GPP TS 38.323: Packet Data Convergence Protocol (PDCP)

[0057] - 3GPP TS 38.331: Radio Resource Control (RRC) protocol

[0058] - 3GPP TS 37.324: Service Data Adaptation Protocol (SDAP)

[0059] - 3GPP TS 37.340: Multi-connectivity; General description

[0060] In the disclosure, a user equipment (UE) can be a fixed or mobile device. Examples of the UE include various devices that transmit user data and / or various control information to a base station (BS) and receive user data and / or various control information from the base station (BS). In the disclosure, the BS generally refers to a fixed station that communicates with a UE and / or other BSs and exchanges various data and control information with the UE and other BSs. The BS can be referred to as an advanced base station (ABS), a node B (NB), an evolved node B (eNB), a base transceiver system (BTS), an access point (AP), a processing server (PS), etc. In particular, the BS of the UMTS is referred to as the NB, the BS of the enhanced packet core (EPC) / long term evolution (LTE) system is referred to as the eNB, and the BS of the new radio (NR) system is referred to as the gNB.

[0061] In the disclosure, a node refers to a point that can transmit / receive a radio signal by communicating with a UE. Various types of BSs can serve as a node regardless of their terms. For example, a BS, a node B (NB), an e-node B (eNB), a pico eNB (PeNB), a home eNB (HeNB), a relay, a repeater, etc. can be a node. In addition, the node can not be a BS. For example, the node can be a radio frequency remote head (RRH) or a radio frequency remote unit (RRU). The power level of the RRH or RRU is generally lower than that of the BS. Since the RRH or RRU (hereinafter, RRH / RRU) is generally connected to the BS through a dedicated line such as an optical cable, cooperative communication between the RRH / RRU and the BS can be smoothly performed compared to cooperative communication between the BS connected through a radio line. Each node is installed with at least one antenna. The antenna can include a physical antenna or an antenna port or a virtual antenna.

[0062] In the disclosure, the term "cell" can refer to a geographical area to which one or more nodes provide a communication system, or refer to a radio resource. The "cell" of a geographical area can be understood as a coverage in which a node can provide a service using a carrier, and the "cell" as a radio resource (e.g., time-frequency resource) is associated with a bandwidth (BW) as a frequency range configured by the carrier. The "cell" associated with the radio resource is defined by a combination of downlink resources and uplink resources (e.g., a combination of a downlink (DL) component carrier (CC) and an uplink (UL) CC). A cell can be configured only by downlink resources, or can be configured by downlink resources and uplink resources. Since the DL coverage as a range in which a node can transmit an effective signal and the UL coverage as a range in which a node can receive an effective signal from a UE depend on a carrier that carries a signal, the coverage of a node can be associated with the coverage of the "cell" of a radio resource used by the node. Therefore, the term "cell" can sometimes be used to indicate the service coverage of a node, at other times to indicate a radio resource, or at other times to indicate a range in which a signal using a radio resource can reach with an effective strength.

[0063] In the disclosure, a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) refer to a set of time-frequency resources or resource elements (REs) that carry downlink control information (DCI) and a set of time-frequency resources or REs that carry downlink data, respectively. In addition, a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), and a physical random access channel (PRACH) refer to a set of time-frequency resources or REs that carry uplink control information (UCI), a set of time-frequency resources or REs that carry uplink data, and a set of time-frequency resources or REs that carry a random access signal, respectively.

[0064] In Carrier Aggregation (CA), two or more CCs are aggregated. A UE can simultaneously receive or transmit on one or multiple CCs according to its capability. Both contiguous and non-contiguous CCs are supported for CA. When CA is configured, the UE has only one Radio Resource Control (RRC) connection with the network. At RRC connection setup / re-establishment / handover, one serving cell provides Non-Access Stratum (NAS) mobility information, and at RRC connection re-establishment / handover, one serving cell provides a secure input. This cell is referred to as the Primary Cell (PCell). The PCell is the cell operating at the primary frequency where the UE performs the initial connection establishment procedure or initiates the connection re-establishment procedure. Depending on UE capability, Secondary Cells (SCells) can be configured to form a set of serving cells together with the PCell. An SCell is a cell providing additional radio resources on a secondary frequency. Thus, a set of serving cells configured for a UE always consists of one PCell and one or more SCells. In this disclosure, the term Special Cell (SpCell) refers to the PCell of the Master Cell Group (MCG) or the PSCell of the Secondary Cell Group (SCG) for Dual Connectivity (DC) operation, and otherwise the term Special Cell refers to the PCell. The SpCell supports Physical Uplink Control Channel (PUCCH) transmission and contention-based random access, and is always in an activated state. The MCG is a set of serving cells associated with a master node including the SpCell (PCell) and optionally one or more SCells. The SCG is a subset of serving cells associated with a secondary node including the PSCell and zero or more SCells for a UE configured with DC. For a UE in RRC CONNECTED not configured with CA / DC, there is only one serving cell consisting of the PCell. For a UE in RRC CONNECTED configured with CA / DC, the term "serving cells" is used to denote the set of cells consisting of the SpCell and all SCells.

[0065] The MCG is a set of serving cells associated with a master BS that at least terminates an S1-MME, and the SCG is a set of serving cells associated with a secondary BS that provides additional radio resources for the UE but is not the master BS. The SCG includes a primary SCell (PSCell) and optionally one or more SCells. In DC, two MAC entities are configured in the UE: one for the MCG and one for the SCG. Each MAC entity is configured by RRC with a serving cell that supports PUCCH transmission and contention-based random access. In this disclosure, the term SpCell refers to such a cell, and the term SCell refers to the other serving cells. Depending on whether the MAC entity is associated with the MCG or the SCG, respectively, the term SpCell refers to the PCell of the MCG or the PSCell of the SCG.

[0066] In the present disclosure, monitoring a channel means attempting to decode the channel. For example, monitoring a physical downlink control channel (PDCCH) means attempting to decode a PDCCH (or a PDCCH candidate).

[0067] In the present disclosure, "C-RNTI" means cell RNTI, "SI-RNTI" means system information RNTI, "P-RNTI" means paging RNTI, "RA-RNTI" means random access RNTI, "SC-RNTI" means single cell RNTI, "SL-RNTI" means sidelink RNTI, "SPS C-RNTI" means semi-persistent scheduling C-RNTI, and "CS-RNTI" means configured scheduling RNTI.

[0068] Figure 1 An example of a communication system 1 to which implementations of the present disclosure is applied is illustrated.

[0069] Three major requirement categories for 5G include: (1) an enhanced mobile broadband (eMBB) category, (2) a massive machine type communications (mMTC) category, and (3) an ultra-reliable and low latency communications (URLLC) category.

[0070] Some use cases can require multiple categories for optimization, and other use cases can focus on only one key performance indicator (KPI). 5G supports such various use cases using a flexible and reliable method.

[0071] eMBB far exceeds basic mobile Internet access and covers rich bi-directional work and media and entertainment applications in cloud and augmented reality. Data is one of the key enablers in the 5G core engine, and in the 5G era, a dedicated voice service can be first provided. In 5G, it is expected that voice will be simply handled as an application program using a data connection provided by a communication system. The main reason for increasing traffic capacity is due to an increase in content size and an increase in the number of applications requiring high data transfer rates. As more and more devices are connected to the Internet, streaming services (audio and video), conversational video, and mobile Internet access will be more widely used. This many applications require always-on connections in order to push real-time information and alerts to users. Cloud storage and applications are rapidly increasing in mobile communication platforms and can be applied to both work and entertainment. Cloud storage is a special use case that accelerates the growth of uplink data transfer rates. 5G is also used for remote work of the cloud. When using a haptic interface, 5G requires much lower end-to-end latency to maintain a good user experience. Entertainment, such as cloud gaming and video streaming, is another core element that increases the demand for mobile broadband capabilities. Entertainment is essential for smartphones and tablets everywhere, including high-mobility environments such as trains, vehicles, and airplanes. Other use cases are augmented reality for entertainment and information search. In this case, augmented reality requires very low latency and instantaneous data capacity.

[0072] In addition, one of the most expected 5G use cases involves functionality that is able to smoothly connect embedded sensors in all fields, i.e., mMTC. It is expected that the number of potential IoT devices will reach 204 billion in 2020. Industrial IoT is one of the categories that plays a major role in implementing smart cities, asset tracking, smart utilities, agriculture, and security infrastructure through 5G.

[0073] URLLC includes new services that will change industries, such as autonomous vehicles through remote control of main infrastructure and ultra-reliable / available low-latency links. The level of reliability and latency is necessary to control smart grids, automation industries, implement robots, and control and adjust drones.

[0074] 5G is a means of providing a stream that is evaluated as hundreds of megabits per second to gigabits per second, and can complement fiber-to-the-home (FTTH) and wired broadband-based broadband (or DOCSIS). Such fast speed is required to deliver TV with 4K or more (6K, 8K, and more) resolution, as well as virtual reality and augmented reality. Virtual reality (VR) and augmented reality (AR) applications include almost immersive motion games. Specific applications can require special network configurations. For example, for VR games, game companies need to incorporate core servers into edge network servers of network operators in order to minimize latency.

[0075] Automotive is expected to be a new important enabler in 5G together with many use cases for mobile communication for vehicles. For example, entertainment of passengers requires high simultaneous capacity and mobile broadband with high mobility. This is because future users continue to expect high quality connectivity regardless of their location and speed. Another use case in the automotive field is an AR dashboard. The AR dashboard enables a driver to recognize objects in the dark in addition to objects seen from the front window and displays the distance from the objects and the movement of the objects by overlapping with information told to the driver. In the future, wireless modules enable communication between vehicles, exchange of information between vehicles and supporting infrastructure, and exchange of information between vehicles and other connected devices (e.g., devices accompanied by pedestrians). Safety systems guide alternative routes of behavior so that drivers can drive more safely, thereby reducing the risk of accidents. The next stage will be remotely controlled or self-driving vehicles. This requires very high reliability and very fast communication between different self-driving vehicles and between vehicles and infrastructure. In the future, self-driving vehicles will perform all driving activities and drivers will only focus on abnormal traffic that the vehicles cannot recognize. The technical requirements for self-driving vehicles require ultra-low latency and ultra-high reliability, increasing traffic safety to a level that cannot be achieved by humans.

[0076] Smart cities and smart homes / buildings, mentioned as smart societies, will be embedded in high-density wireless sensor networks. Distributed networks of smart sensors will identify conditions for cost- and energy-efficient maintenance of cities or homes. Similar configurations can be performed for respective homes. All temperature sensors, window and heating controllers, burglar alarms, and home appliances are wirelessly connected. Many of these sensors are typically low in data transmission rate, power, and cost. However, a specific type of device can need real-time HD video to perform monitoring.

[0077] Consumption and distribution of energy including heat or gas are distributed at a higher level, so that automatic control of the distribution sensor network is required. A smart grid collects information and connects sensors to each other using digital information and communication technology, thereby acting according to the collected information. Since this information can include behaviors of supply companies and consumers, the smart grid can improve distribution of fuels such as electricity through methods with efficiency, reliability, economic feasibility, production sustainability, and automation. The smart grid can also be considered another sensor network with low latency.

[0078] Mission critical applications (e.g., eHealth) are one of the 5G use cases. The health sector includes many applications that can benefit from mobile communications. A communication system can support remote treatment in which clinical treatment is provided in a distant place. Remote treatment can help reduce barriers to distance and improve access to medical services that cannot be continuously obtained in remote rural areas. Remote treatment is also used to perform important treatment and save lives in emergency situations. A wireless sensor network based on mobile communication can provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

[0079] Wireless and mobile communication is gradually becoming important in the field of industrial applications. Wiring is high in installation and maintenance costs. Therefore, the possibility of replacing cables with reconfigurable wireless links is an attractive opportunity in many industrial fields. However, in order to achieve such a replacement, it is necessary for the wireless connection to establish a delay, reliability, and capacity similar to that of a cable, and it is necessary to simplify the management of the wireless connection. When a connection to 5G is required, low latency and very low error probability are new requirements.

[0080] Logistics and freight tracking is an important use case for mobile communication that allows the use of a location-based information system to track inventory and packages anywhere. The use case of logistics and freight tracking often requires low data rates, but requires location information with a wide range and reliability.

[0081] Reference Figure 1 The communication system 1 includes wireless devices, base stations (BSs), and networks. Although Figure 1 A 5G network is exemplified as an example of the network of the communication system 1, but implementations of the present disclosure are not limited to the 5G system, and can be applied to future communication systems other than the 5G system.

[0082] The BS and the network can be implemented as a wireless device, and a specific wireless device 200a can operate as a BS / network node with respect to other wireless devices.

[0083] A wireless device denotes a device that performs communication using a radio access technology (RAT) (e.g., 5G new RAT (NR) or long term evolution (LTE)), and can be referred to as a communication / wireless / 5G device. The wireless device can include, but is not limited to, a robot 100a, a vehicle 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an artificial intelligence (AI) device / server 400. For example, the vehicle can include a vehicle with a wireless communication function, an autonomous vehicle, and a vehicle capable of performing communication between vehicles. The vehicle can include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device can include an augmented reality (AR) / virtual reality (VR) / mixed reality (MR) device, and can be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The handheld device can include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or smartglasses), and a computer (e.g., a notebook). The home appliance can include a TV, a refrigerator, and a washing machine. The IoT device can include a sensor and a smartmeter.

[0084] In the disclosure, the wireless devices 100a to 100f can be referred to as user equipment (UE). The user equipment (UE) can include, for example, a cellular phone, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle with autonomous driving function, a connected car, an unmanned aerial vehicle (UAV), an artificial intelligence (AI) module, a robot, an augmented reality (AR) device, a virtual reality (VR) device, a mixed reality (MR) device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a Fintech device (or a financial device), a security device, a weather / environment device, a device related to a 5G service, or a device related to a fourth industrial revolution field. The unmanned aerial vehicle (UAV) can be, for example, a flying vehicle driven by a wireless control signal without a person being on board. The VR device can include, for example, a device for implementing an object or a background of a virtual world. The AR device can include, for example, a device implemented by connecting an object or a background of a virtual world to an object or a background of a real world. The MR device can include, for example, a device implemented by merging an object or a background of a virtual world into an object or a background of a real world. The hologram device can include, for example, a device for implementing a stereoscopic image of 360 degrees by recording and reproducing stereoscopic information using an interference phenomenon of light generated when two lasers called holography meet. The public safety device can include, for example, an image relay device or an image device wearable on a user's body. The MTC device and the IoT device can be, for example, a device that does not require direct human intervention or manipulation. For example, the MTC device and the IoT device can include a smart meter, a vending machine, a thermometer, a smart bulb, a door lock, or various sensors. The medical device can be, for example, a device for the purpose of diagnosing, treating, mitigating, curing, or preventing a disease. For example, the medical device can be a device for the purpose of diagnosing, treating, mitigating, or correcting an injury or impairment. For example, the medical device can be a device for the purpose of inspecting, replacing, or modifying a structure or function. For example, the medical device can be a device for the purpose of regulating pregnancy. For example, the medical device can include a device for treatment, a device for operation, a device for (in vitro) diagnosis, a hearing aid, or a device for surgery. The security device can be, for example, a device installed to prevent a danger that can occur and to maintain safety. For example, the security device can be a camera, a CCTV, a recorder, or a black box. The Fintech device can be, for example, a device capable of providing a financial service such as mobile payment. For example, the Fintech device can include a payment device or a point of sale (POS) system. The weather / environment device can include, for example, a device for monitoring or predicting weather / environment.

[0085] The wireless devices 100a-100f can be connected to the network 300 via the BSs 200. The AI technology can be applied to the wireless devices 100a-100f, and the wireless devices 100a-100f can be connected to the AI server 400 via the network 300. The network 300 can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a super 5G network. Although the wireless devices 100a-100f can communicate with each other through the BSs 200 / network 300, the wireless devices 100a-100f can perform direct communication (e.g., sidelink communication) with each other without going through the BS / network. For example, the vehicles 100b-1 and 100b-2 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). The IoT devices (e.g., sensors) can perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a-100f.

[0086] Wireless communication / connections 150a and 150b can be established between the wireless devices 100a-100f / BSs 200-BS 200. In this context, the wireless communication / connections can be established through various RATs (e.g., 5G NR) such as uplink / downlink communication 150a and sidelink communication 150b (or D2D communication). The wireless devices and the BSs / wireless devices can transmit / receive radio signals to / from each other through the wireless communication / connections 150a and 150b. For example, the wireless communication / connections 150a and 150b can transmit / receive signals through various physical channels. To this end, at least a part of various configuration information configuration procedures, various signal processing procedures (e.g., channel encoding / decoding, modulation / demodulation, and resource mapping / demapping), and resource allocation procedures for transmitting / receiving radio signals can be performed based on various proposals of the disclosure.

[0087] Figure 2 is a block diagram illustrating an example of a communication device that can perform the method according to the disclosure.

[0088] Referring to Figure 2 , the first wireless device 100 and the second wireless device 200 can transmit / receive radio signals to / from an external device through various RATs (e.g., LTE and NR). In Figure 2 , the {first wireless device 100 and the second wireless device 200} can correspond to the {wireless devices 100a-100f and the BSs 200} and / or the {wireless devices 100a-100f and the wireless devices 100a-100f} of Figure 1

[0089] ​The first wireless device 100 can include one or more processors 102 and one or more memories 104, and additionally further include one or more transceivers 106 and / or one or more antennas 108. The processor(s) 102 can control the memory(s) 104 and / or the transceiver(s) 106 and can be configured to implement the functions, processes, and / or methods described in the present disclosure. For example, the processor(s) 102 can process information within the memory(s) 104 to generate first information / signals and then transmit radio signals including the first information / signals through the transceiver(s) 106. The processor(s) 102 can receive radio signals including second information / signals through the transceiver(s) 106 and then store information obtained by processing the second information / signals in the memory(s) 104. The memory(s) 104 can be connected to the processor(s) 102 and can store various information related to operations of the processor(s) 102. For example, the memory(s) 104 can store software code including commands for executing parts or all of the processes controlled by the processor(s) 102 or for executing the processes and / or methods described in the present disclosure. In this document, the processor(s) 102 and the memory(s) 104 can be part of a communication modem / circuitry / chip designed to implement a RAT (e.g., LTE or NR). The transceiver(s) 106 can be connected to the processor(s) 102 and transmit and / or receive radio signals through the one or more antennas 108. Each of the transceiver(s) 106 can include a transmitter and / or a receiver. The transceiver(s) 106 can be used interchangeably with radio frequency (RF) unit(s). In the present disclosure, a wireless device can denote a communication modem / circuitry / chip.

[0090] The second wireless device 200 can include one or more processors 202 and one or more memories 204, and additionally further include one or more transceivers 206 and / or one or more antennas 208. The processor(s) 202 can control the memory(s) 204 and / or the transceiver(s) 206 and can be configured to implement the functions, processes, and / or methods described in the present disclosure. For example, the processor(s) 202 can process information within the memory(s) 204 to generate third information / signals and then transmit radio signals including the third information / signals through the transceiver(s) 206. The processor(s) 202 can receive radio signals including fourth information / signals through the transceiver(s) 206 and then store information obtained by processing the fourth information / signals in the memory(s) 204. The memory(s) 204 can be connected to the processor(s) 202 and can store various information related to operations of the processor(s) 202. For example, the memory(s) 204 can store software code including commands for executing parts or all of the processes controlled by the processor(s) 202 or for executing the processes and / or methods described in the present disclosure. In this document, the processor(s) 202 and the memory(s) 204 can be part of a communication modem / circuitry / chip designed to implement a RAT (e.g., LTE or NR). The transceiver(s) 206 can be connected to the processor(s) 202 and transmit and / or receive radio signals through the one or more antennas 208. Each of the transceiver(s) 206 can include a transmitter and / or a receiver. The transceiver(s) 206 can be used interchangeably with RF unit(s). In the present disclosure, a wireless device can denote a communication modem / circuitry / chip.

[0091] Hereinafter, the hardware elements of the wireless devices 100 and 200 will be described more specifically. One or more protocol layers can be implemented by, without limitation, the one or more processors 102 and 202. For example, the one or more processors 102 and 202 can implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). The one or more processors 102 and 202 can generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure. The one or more processors 102 and 202 can generate messages, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure. The one or more processors 102 and 202 can generate signals (e.g., baseband signals) including the PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure and provide the generated signals to the one or more transceivers 106 and 206. The one or more processors 102 and 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106 and 206 and acquire the PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure.

[0092] The one or more processors 102 and 202 can be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102 and 202 can be implemented by hardware, firmware, software, or a combination thereof. For example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) can be included in the one or more processors 102 and 202. The functions, procedures, proposals, and / or methods disclosed in the present disclosure can be implemented using firmware or software, and the firmware or software can be configured to include modules, procedures, or functions. Firmware or software configured to perform the functions, procedures, proposals, and / or methods disclosed in the present disclosure can be included in the one or more processors 102 and 202 or stored in the one or more memories 104 and 204 to be driven by the one or more processors 102 and 202. The functions, procedures, proposals, and / or methods disclosed in the present disclosure can be implemented using firmware or software in the form of codes, commands, and / or command sets.

[0093] One or more memories 104 and 204 can be connected to the one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories 104 and 204 can be configured by read-only memory (ROM), random-access memory (RAM), electrically programmable read-only memory (EPROM), flash memory, hard disk drive, register, cache memory, computer readable storage media, and / or combinations thereof. The one or more memories 104 and 204 can be located inside and / or outside the one or more processors 102 and 202. The one or more memories 104 and 204 can be connected to the one or more processors 102 and 202 through various technologies such as wired or wireless connections.

[0094] The one or more transceivers 106 and 206 can transmit the user data, control information, and / or radio signals / channels mentioned in the methods and / or operational flowcharts of the disclosure to one or more other apparatuses. The one or more transceivers 106 and 206 can receive the user data, control information, and / or radio signals / channels mentioned in the functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the disclosure from one or more other apparatuses. For example, the one or more transceivers 106 and 206 can be connected to the one or more processors 102 and 202 and transmit and receive radio signals. For example, the one or more processors 102 and 202 can perform control so that the one or more transceivers 106 and 206 can transmit user data, control information, or radio signals to one or more other apparatuses. The one or more processors 102 and 202 can perform control so that the one or more transceivers 106 and 206 can receive user data, control information, or radio signals from one or more other apparatuses. The one or more transceivers 106 and 206 can be connected to the one or more antennas 108 and 208, and the one or more transceivers 106 and 206 can be configured to transmit and receive the user data, control information, and / or radio signals / channels mentioned in the functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the disclosure through the one or more antennas 108 and 208. In the disclosure, the one or more antennas can be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). The one or more transceivers 106 and 206 can convert received radio signals / channels, etc. from RF band signals to baseband signals in order to facilitate processing of received user data, control information, radio signals / channels, etc. using the one or more processors 102 and 202. The one or more transceivers 106 and 206 can convert user data, control information, radio signals / channels, etc. processed using the one or more processors 102 and 202 from baseband signals to RF band signals. To this end, the one or more transceivers 106 and 206 can include (analog) oscillators and / or filters. For example, the transceivers 106 and 206 can up-convert OFDM baseband signals to carrier frequencies by their (analog) oscillators and / or filters under the control of the processors 102 and 202 and transmit the up-converted OFDM signals at the carrier frequencies. The transceivers 106 and 206 can receive OFDM signals at the carrier frequencies and down-convert the OFDM signals to OFDM baseband signals by their (analog) oscillators and / or filters under the control of the processors 102 and 202.

[0095] In implementations of the disclosure, the UE can operate as a transmitting apparatus in uplink (UL) and a receiving apparatus in downlink (DL). In implementations of the disclosure, the BS can operate as a receiving apparatus in UL and a transmitting apparatus in DL. Hereinafter, for convenience of description, unless otherwise stated or described, it is mainly assumed that the first wireless device 100 operates as a UE and the second wireless device 200 operates as a BS. For example, the processor 102 connected to, installed on, or activated in the first wireless device 100 can be configured to perform a UE behavior according to implementations of the disclosure or control the transceiver 106 to perform a UE behavior according to implementations of the disclosure. The processor 202 connected to, installed on, or activated in the second wireless device 200 can be configured to perform a BS behavior according to implementations of the disclosure or control the transceiver 206 to perform a BS behavior according to implementations of the disclosure.

[0096] In the disclosure, at least one memory (e.g., 104 or 204) can store instructions or programs that, when executed, cause at least one processor operatively connected thereto to perform operations according to some embodiments or implementations of the disclosure.

[0097] In the disclosure, a computer-readable storage medium stores at least one instruction or computer program that, when executed by at least one processor, causes the at least one processor to perform operations according to some embodiments or implementations of the disclosure.

[0098] In the disclosure, a processing apparatus or device can include at least one processor, and at least one computer memory connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some embodiments or implementations of the disclosure.

[0099] Figure 3 An example of a frame structure in a 3GPP-based wireless communication system is illustrated.

[0100] Figure 3The illustrated frame structure is merely an example, and the number of subframes, the number of slots, and / or the number of symbols in a frame can be changed differently. In 3GPP-based wireless communication systems, OFDM numerology (e.g., subcarrier spacing (SCS), transmission time interval (TTI) duration) can be configured differently among multiple cells aggregated for one UE. For example, if a UE is configured with different SCS for cells aggregated for a cell, the (absolute time) duration of a time resource (e.g., subframe, slot, or TTI) that includes the same number of symbols can be different among the aggregated cells. In this document, a symbol can include an OFDM symbol (or CP-OFDM symbol), an SC-FDMA symbol (or discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol).

[0101] Referring to Figure 3 , downlink and uplink transmissions are organized into frames. Each frame has a duration of 10 ms. Each frame is divided into two half-frames with each half-frame having a duration of 5 ms. Each half-frame includes 5 subframes with each subframe having a duration of 1 ms. Each subframe is divided into slots and the number of slots in a subframe depends on the subcarrier spacing. Each slot includes 14 or 12 CP-based OFDM symbols. In normal CP, each slot includes 14 OFDM symbols and in extended CP, each slot includes 12 OFDM symbols. The numerology is based on an indexable subcarrier spacing . The following table shows the number of OFDM symbols per slot, the number of slots per frame, and the number of slots per subframe for normal CP according to the subcarrier spacing .

[0102] [Table 1]

[0103]

[0104] The following table shows the number of OFDM symbols per slot, the number of slots per frame, and the number of slots per subframe for extended CP according to the subcarrier spacing .

[0105] [Table 2]

[0106]

[0107] A slot includes a number of symbols (e.g., 14 or 12 symbols) in the time domain. For each numerology (e.g., subcarrier spacing) and carrier, a common resource block (CRB) is indicated by higher layer signaling (e.g., radio resource control (RRC) signaling) In the beginning, it was defined Subcarriers and A resource grid of OFDM symbols, wherein... It represents the number of resource blocks in the resource grid, with the subscript x representing the DL for the downlink and the UL for the uplink. This refers to the number of subcarriers in each resource block. In 3GPP-based wireless communication systems, Typically 12. For a given antenna port p, subcarrier spacing configuration u, and transmission direction (DL or UL), there exists a resource grid. The carrier bandwidth for the subcarrier spacing configuration u... Given by higher-layer parameters (e.g., RRC parameters). Each element in the resource grid for antenna port p and subcarrier spacing configuration u is called a resource element (RE), and a complex symbol can be mapped to each RE. Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index l representing the symbol position relative to a reference point in the time domain. In 3GPP-based wireless communication systems, a resource block is defined by 12 consecutive subcarriers in the frequency domain.

[0108] In 3GPP NR systems, resource blocks are classified into Common Resource Blocks (CRBs) and Physical Resource Blocks (PRBs). CRBs are numbered upwards from 0 in the frequency domain based on subcarrier spacing configuration u. The center of subcarrier 0 in CRB 0 for subcarrier spacing configuration u coincides with "point A," which serves as the common reference point for the resource block grid. In 3GPP NR systems, PRBs are defined within the Bandwidth Part (BWP) and numbered from 0 to... Number, where i is the number of the bandwidth section. Physical resource blocks within bandwidth section i. With public resource blocks The relationship between them is as follows: ,in A BWP is a common resource block relative to CRB 0. A BWP comprises multiple consecutive resource blocks. A carrier can include up to N (e.g., 5) BWPs. A UE can be configured with one or more BWPs on a given component carrier. Only one BWP can be active at a time among those configured for the UE. The active BWP is defined within the UE's operating bandwidth of the cell.

[0109] The NR band can be defined as two types of frequency ranges, FR1 and FR2. FR2 can also be referred to as millimeter wave (mmW). The frequency range in which NR can operate is shown as described in Table 3.

[0110] [Table 3]

[0111]

[0112] Figure 4 An example of a protocol stack in a 3GPP-based wireless communication system is illustrated.

[0113] Specifically, Figure 4 (a) of FIG. 1 illustrates an example of a radio interface user plane protocol stack between a UE and a base station (BS) and Figure 4 (b) of FIG. 1 illustrates an example of a radio interface control plane protocol stack between the UE and the BS. The control plane refers to a path through which control messages for managing a call by the UE and the network are transmitted. The user plane refers to a path that transmits data (e.g., voice data or Internet packet data) generated in an application layer. Referring to Figure 4 (a) of FIG. 1, the user plane protocol stack can be divided into a first layer (Layer 1) (i.e., a physical (PHY) layer) and a second layer (Layer 2). Referring to Figure 4 (b) of FIG. 1, the control plane protocol stack can be divided into Layer 1 (i.e., a PHY layer), Layer 2, Layer 3 (e.g., a radio resource control (RRC) layer), and a non-access stratum (NAS) layer. Layer 1, Layer 2, and Layer 3 are referred to as an access stratum (AS).

[0114] The NAS control protocol terminates at an access management function (AMF) on a network side and performs functions such as authentication, mobility management, security control, etc.

[0115] In the 3GPP LTE system, Layer 2 is separated into the following sublayers: medium access control (MAC), radio link control (RLC), and packet data convergence protocol (PDCP). In the 3GPP new radio (NR) system, Layer 2 is separated into the following sublayers: MAC, RLC, PDCP, and SDAP. The PHY layer provides a transport channel to the MAC sublayer, the MAC sublayer provides a logical channel to the RLC sublayer, the RLC sublayer provides an RLC channel to the PDCP sublayer, the PDCP sublayer provides a radio bearer to the SDAP sublayer. The SDAP sublayer provides a quality of service (QoS) flow to the 5G core network.

[0116] In the 3GPP NR system, the main services and functions of the SDAP include: mapping between QoS flows and data radio bearers; marking QoS flow ID (QFI) in both DL and UL packets. A single SDAP protocol entity is configured per individual PDU session.

[0117] In 3GPP NR systems, the main services and functions of the RRC sublayer include: broadcast of system information related to AS and NAS; paging initiated by 5G core (5GC) or NG-RAN; establishment, maintenance and release of an RRC connection between the UE and NG-RAN; security functions including key management; establishment, configuration, maintenance and release of signaling radio bearers (SRBs) and data radio bearers (DRBs); mobility functions (including: handover and context transfer; control of UE cell selection and reselection and cell selection and reselection; inter-RAT mobility); QoS management functions; UE measurement reporting and control of reporting; detection of radio link failure and recovery; transfer of NAS messages from UE to NAS / from NAS to UE.

[0118] In 3GPP NR systems, the main services and functions of the PDCP sublayer for the user plane include: sequence numbering; header compression and decompression: ROHC only; transfer of user data; reordering and duplicate detection; in-order delivery; PDCP PDU routing (in case of split bearers); retransmission of PDCP SDUs; ciphering, deciphering and integrity protection; PDCP SDU discard; PDCP re-establishment and data recovery for RLC AM; PDCP status reporting for RLC AM; duplication of PDCP PDUs and duplicate discard indication to lower layers. The main services and functions of the PDCP sublayer for the control plane include: sequence numbering; ciphering, deciphering and integrity protection; transfer of control plane data; reordering and duplicate detection; in-order delivery; duplication of PDCP PDUs and duplicate discard indication to lower layers.

[0119] The RLC sublayer supports three transmission modes: transparent mode (TM); unacknowledged mode (UM); and acknowledged mode (AM). RLC configuration is per logical channel and does not depend on numerologies and / or transmission durations. In 3GPP NR systems, the main services and functions of the RLC sublayer depend on the transmission mode and include: transfer of upper layer PDUs; independent sequence numbering in PDCP (UM and AM); error correction through ARQ (AM only); segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs; reassembly of SDUs (AM and UM); duplicate detection (AM only); RLC SDU discard (AM and UM); RLC re-establishment; protocol error detection (AM only).

[0120] In 3GPP NR system, the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; multiplexing / demultiplexing of MAC SDUs belonging to one or different logical channels onto / from transport channels towards / from the physical layer; scheduling information reporting; error correction through HARQ (one HARQ entity per cell in case of carrier aggregation (CA)); priority handling between UEs through dynamic scheduling; priority handling between logical channels of one UE through logical channel prioritization; padding. A single MAC entity can support multiple numerologies, transmission timings, and cells. Mapping restrictions in logical channel prioritization control which numerology(s), cell(s), and transmission timing(s) a logical channel can use. The MAC offers different kinds of data transfer services. To accommodate different kinds of data transfer services, multiple types of logical channels are defined, i.e., each logical channel supports transfer of a specific type of information. Each logical channel type is defined by what type of information is transferred. Logical channels are classified into two groups: Control Channels and Traffic Channels. Control channels are used for the transfer of control plane information only, and traffic channels are used for the transfer of user plane information only. Broadcast Control Channel (BCCH) is a downlink logical channel for broadcasting system control information, Paging Control Channel (PCCH) is a downlink logical channel that transfers paging information, system information change notifications, and indications of ongoing PWS broadcasts, Common Control Channel (CCCH) is a logical channel for transmitting control information between UEs and the network and used by UEs that have not joined a Cell yet and by UEs that have no RRC connection at all, and Dedicated Control Channel (DCCH) is a point-to-point bidirectional logical channel that transmits dedicated control information between a UE and the network and used by UEs having an RRC connection. Dedicated Traffic Channel (DTCH) is a point-to-point logical channel, implemented for one UE only, for the transfer of user information. A DTCH can exist in both uplink and downlink. In downlink, there is the following mapping between logical channels and transport channels: BCCH can be mapped to BCH; BCCH can be mapped to downlink shared channel (DL-SCH); PCCH can be mapped to PCH; CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped to DL-SCH. In uplink, there is the following mapping between logical channels and transport channels: CCCH can be mapped to uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.

[0121] Figure 5 A data flow example in 3GPP NR system is illustrated.

[0122] In Figure 5In the middle, "RB" denotes a radio bearer, and "H" denotes a header. Radio bearers are classified into two groups: data radio bearers (DRBs) for user plane data and signaling radio bearers (SRBs) for control plane data. A MAC PDU is transmitted / received to / from an external device using radio resources through a PHY layer. The MAC PDU arrives at the PHY layer in the form of a transport block.

[0123] At the PHY layer, an uplink transport channel UL-SCH and RACH are mapped to a physical uplink shared channel (PUSCH) and a physical random access channel (PRACH), respectively, and a downlink transport channel DL-SCH, BCH, and PCH are mapped to a physical downlink shared channel (PDSCH), a physical broadcast channel (PBCH), and a PDSCH, respectively. At the PHY layer, uplink control information (UCI) is mapped to a PUCCH, and downlink control information (DCI) is mapped to a PDCCH. A UE transmits a MAC PDU related to the UL-SCH via the PUSCH based on a UL grant, and a BS transmits a MAC PDU related to the DL-SCH via the PDSCH based on a DL assignment.

[0124] In order to transmit a data unit of the present disclosure on the UL-SCH, a UE should have an uplink resource available to the UE. In order to receive a data unit of the present disclosure on the DL-SCH, a UE should have a downlink resource available to the UE. Resource allocation includes time domain resource allocation and frequency domain resource allocation. In the present disclosure, uplink resource allocation is also referred to as an uplink grant, and downlink resource allocation is also referred to as a downlink assignment. An uplink grant is either dynamically received by a UE on a PDCCH in a random access response or semi-persistently configured to a UE by RRC. A downlink assignment is either dynamically received by a UE on a PDCCH or semi-persistently configured to a UE by RRC signaling from a BS.

[0125] In the UL, the BS can dynamically allocate resources to a UE on the PDCCH via a cell radio network temporary identifier (C-RNTI). The UE always monitors the PDCCH in order to find possible grants for uplink transmissions when its downlink reception is enabled (controlled by discontinuous reception (DRX) when configured to be active). In addition, the BS can allocate uplink resources for initial HARQ transmissions to the UE by configuring grants. Two types of configured uplink grants are defined: Type 1 and Type 2. For Type 1, the RRC directly provides the configured uplink grant (including periodicity). For Type 2, the RRC defines the periodicity of the configured uplink grant, while a PDCCH addressed to a configured scheduling RNTI (CS-RNTI) can signal and activate it, or deactivate it; i.e., a PDCCH addressed to the CS-RNTI indicates that the uplink grant can be implicitly reused according to the periodicity defined by the RRC until deactivation.

[0126] In the DL, the BS can dynamically allocate resources to a UE on the PDCCH via a C-RNTI. The UE always monitors the PDCCH in order to find possible assignments when its downlink reception is enabled (controlled by DRX when configured to be active). In addition, by semi-persistent scheduling (SPS), the BS can allocate downlink resources for initial HARQ transmissions to the UE: the RRC defines the periodicity of the configured downlink assignment, while a PDCCH addressed to a CS-RNTI can signal and activate it, or deactivate it. In other words, a PDCCH addressed to the CS-RNTI indicates that the downlink assignment can be implicitly reused according to the periodicity defined by the RRC until deactivation.

[0127] <Resource allocation by PDCCH (i.e., resource allocation by DCI)>

[0128] The PDCCH can be used to schedule DL transmissions on the PDSCH and UL transmissions on the PUSCH, where downlink control information (DCI) on the PDCCH includes: a downlink assignment containing at least modulation and coding format (e.g., a modulation and coding scheme (MCS) index IMCS), resource allocation, and hybrid-ARQ information related to a DL-SCH; or an uplink scheduling grant containing at least modulation and coding format, resource allocation, and hybrid-ARQ information related to a UL-SCH. The size and usage of the DCI carried by one PDCCH varies according to the DCI format. For example, in a 3GPP NR system, DCI format 0_0 or DCI format 0_1 is used for scheduling of PUSCH in one cell, and DCI format 1_0 or DCI format 1_1 is used for scheduling of PDSCH in one cell.

[0129] Figure 6 Examples of PDSCH time domain resource allocation via PDCCH and PUSCH time resource allocation via PDCCH are shown.

[0130] The downlink control information (DCI) carried by the PDCCH for scheduling PDSCH or PUSCH includes the value m of row index m+1 of the allocation table for PDSCH or PUSCH. A predefined default PDSCH time domain allocation A, B, or C is applied as the PDSCH allocation table, or the pdsch-TimeDomainAllocationList configured by RRC is applied. Similarly, a predefined default PUSCH time domain allocation A is applied as the PUSCH allocation table, or the pusch-TimeDomainAllocationList configured by RRC is applied. Which PDSCH time domain resource allocation configuration and which PUSCH time domain resource allocation table is applied is determined according to fixed / predefined rules (e.g., Table 5.1.2.1.1-1 in 3GPP TS 38.214 v15.3.0, Table 6.1.2.1.1-1 in 3GPP TS 38.214 v15.3.0).

[0131] Each index row in the PDSCH time-domain allocation configuration defines a time slot offset. Start and length indicators Or define the start symbol directly. and allocation length The PDSCH mapping type assumed in PDSCH reception, and each index row in the PUSCH time-domain allocation configuration defines the slot offset. The start and length indicators SLIV, or directly defining the start symbol S and the allocated length L, and the PUSCH mapping type assumed in PUSCH reception. For PDSCH... Or for PUSCH SLIV is the timing difference between a time slot with a PDCCH and a time slot with a corresponding PDSCH or PUSCH. SLIV is a joint indication of the starting symbol S relative to the start of the time slot with the PDSCH or PUSCH and the number L of consecutive symbols counted from symbol S. For the PDSCH / PUSCH mapping type, there are two mapping types: mapping type A, where the demodulation reference signal (DMRS) is located in the 3rd or 4th symbol of the time slot according to RRC signaling; and mapping type B, where the DMRS is located in the first assigned symbol.

[0132] The scheduling DCI includes a frequency domain resource assignment field that provides assignment information about resource blocks for a PDSCH or a PUSCH. For example, the frequency domain resource assignment field can provide a UE with information about a cell for a PDSCH or a PUSCH transmission, information about a bandwidth part for a PDSCH or a PUSCH transmission, information about resource blocks for a PDSCH or a PUSCH transmission.

[0133] <Resource allocation by RRC>

[0134] As described above, in uplink, there are two types of transmissions without dynamic grant: configured grant Type 1, where the uplink grant is provided by RRC and stored as configured grant; and configured grant Type 2, where the uplink grant is provided by PDCCH and stored or cleared as configured uplink grant based on L1 signaling indicating configured uplink grant activation or deactivation. Type 1 and Type 2 are configured by RRC per serving cell and per BWP. Multiple configurations are active simultaneously only on different serving cells. For Type 2, activation and deactivation among serving cells are independent. For the same serving cell, the MAC entity is configured as Type 1 or Type 2.

[0135] When configured grant Type 1 is configured, the UE is provided with at least the following parameters via RRC signaling from the BS:

[0136] - cs-RNTI, which is the CS-RNTI for retransmission;

[0137] - periodicity, which provides the periodicity of the configured grant Type 1;

[0138] - timeDomainOffset, which represents the offset of the resource in time domain with respect to SFN = 0;

[0139] - timeDomainAllocation value m, which provides a row index m+1 pointing to an allocation table, indicating a combination of starting symbol S and length L and PUSCH mapping type;

[0140] - frequencyDomainAllocation, which provides frequency domain resource allocation; and

[0141] - mcsAndTBS, which provides IMCS representing the modulation order, target code rate and transport block size. When configured grant Type 1 is configured by RRC for a serving cell, the UE stores the uplink grant provided by RRC as configured uplink grant for the indicated serving cell and initializes or re-initializes the configured uplink grant to start in symbol S (deduced from SLIV) and periodically re-occur according to timeDomainOffset. After configuring an uplink grant for configured grant Type 1, the UE considers the uplink grant to be repeated in association with every symbol where: [ (SFN x numberOfSlotsPerFrame x numberOfSymbolsPerSlot + (slot number in frame x numberOfSymbolsPerSlot) + symbol number in slot] = (timeDomainOffset x numberOfSymbolsPerSlot + S + N x periodicity) modulo (1024 x numberOfSlotsPerFrame x numberOfSymbolsPerSlot) for all N >= 0.

[0142] When configured grant Type 2 is configured, the UE is provided at least the following parameters via RRC signaling from the BS:

[0143] - cs-RNTI, which is the CS-RNTI for activation, deactivation and retransmission; and

[0144] - periodicity, which provides the periodicity of the configured grant Type 2. Actual uplink grants are provided to the UE by PDCCH (addressed to the CS-RNTI). After configuring an uplink grant for configured grant Type 2, the UE considers the uplink grant to be repeated in association with every symbol where: [ (SFN x numberOfSlotsPerFrame x numberOfSymbolsPerSlot + (slot number in frame x numberOfSymbolsPerSlot) + symbol number in slot] = [(timeDomainOffset x numberOfSymbolsPerSlot + S + N x periodicity) modulo (1024 x numberOfSlotsPerFrame x numberOfSymbolsPerSlot) for all N >= 0. ​​] modulo (1024 x numberOfSlotsPerFrame x numberOfSymbolsPerSlot) for all N >= 0, where SFN, slot and symbol are the SFN, slot and symbol of the first transmission occasion of the PUSCH where the configured uplink grant is (re-)initialized, respectively, and numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive OFDM symbols per slot, respectively. , and SFN, slot and symbol are the SFN, slot and symbol of the first transmission occasion of the PUSCH where the configured uplink grant is (re-)initialized, respectively, and numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive OFDM symbols per slot, respectively.

[0145] For a configured uplink grant, the HARQ process ID associated with the first symbol of the UL transmission is derived from the following equation:

[0146] HARQ process ID = [floor(CURRENT_symbol / periodicity)] modulo nrofHARQ-Processes

[0147] where CURRENT_symbol = (SFN x numberOfSlotsPerFrame x numberOfSymbolsPerSlot + number of slots in the frame x numberOfSymbolsPerSlot + number of symbols in the slot) and numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot as specified in TS 38.211, respectively. CURRENT_symbol refers to the symbol index of the first transmission occasion where repetition bundling occurs. If the configured uplink grant is activated and the associated HARQ process ID is less than nrofHARQ-Processes, the HARQ process is configured for the configured uplink grant.

[0148] For downlink, a UE can be configured with semi-persistent scheduling (SPS) per serving cell and per BWP by RRC signaling from a BS. Multiple configurations can only be active simultaneously on different serving cells. Activation and deactivation of DL SPS is independent between serving cells. For DL SPS, a DL assignment is provided to a UE by PDCCH and stored or flushed based on L1 signaling indicating SPS activation or deactivation. When SPS is configured, the following parameters are provided to the UE via RRC signaling from the BS:

[0149] - cs-RNTI, which is the CS-RNTI for activation, deactivation and retransmission;

[0150] - nrofHARQ-Processes, which provides the number of HARQ processes for the SPS configuration;

[0151] - periodicity, which provides the periodicity of downlink assignments for the SPS configuration.

[0152] When SPS is released by upper layers, all corresponding configurations shall be released.

[0153] After a downlink assignment is configured for SPS, the UE considers the Nth downlink assignment to occur in the following slot: (numberOfSlotsPerFrame x SFN + number of slots in the frame) = [ (numberOfSlotsPerFrame x + ) + N x periodicity x numberOfSlotsPerFrame / 10] modulo (1024 x numberOfSlotsPerFrame), where and are the SFN and slot of the first transmission of PDSCH for which the configured downlink assignment is (re-)initialized, respectively.

[0154] For a configured downlink assignment, the HARQ process ID associated with the slot where the DL transmission starts is derived from the following equation:

[0155] HARQ process ID = [floor (CURRENT_slot x 10 / (numberOfSlotsPerFrame x periodicity)) ] modulo nrofHARQ-Processes

[0156] where CURRENT_slot = [(SFN x numberOfSlotsPerFrame) + number of slots in the frame], and numberOfSlotsPerFrame refers to the number of consecutive slots per frame as specified in TS 38.211.

[0157] If the cyclic redundancy check (CRC) of the corresponding DCI format is scrambled with the CS-RNTI provided by the RRC parameter cs-RNTI and the new data indicator field is set to 0 for the enabled transport block, the UE validates the DL SPS assignment PDCCH or configured UL grant Type 2 PDCCH for scheduling activation or scheduling release. The validation of the DCI format is achieved if all fields for the DCI format are set according to Table 4 or Table 5. Table 4 shows the special fields for DL SPS and UL grant Type 2 scheduling activation PDCCH validation, and Table 5 shows the special fields for DL SPS and UL grant Type 2 scheduling release PDCCH validation.

[0158] [Table 4]

[0159]

[0160] [Table 5]

[0161]

[0162] The actual DL assignment and actual UL grant, as well as the corresponding modulation and coding scheme, are provided by the resource assignment fields (e.g., time domain resource assignment field providing time domain resource assignment value m, frequency domain resource assignment field providing frequency resource block allocation, modulation and coding scheme field) in the DCI format carried by the DL SPS and UL grant Type 2 scheduling activation PDCCH. If the validation is achieved, the UE considers the information in the DCI format as valid activation or valid release of the DL SPS or configured UL grant Type 2.

[0163] For UL, the processor 102 of the present disclosure can transmit (or control the transceiver 106 to transmit) the data unit of the present disclosure based on the UL grant available to the UE. The processor 202 of the present disclosure can receive (or control the transceiver 206 to receive) the data unit of the present disclosure based on the UL grant available to the UE.

[0164] For DL, the processor 102 of the present disclosure can receive (or control the transceiver 106 to receive) the DL data of the present disclosure based on the DL assignment available to the UE. The processor 202 of the present disclosure can transmit (or control the transceiver 206 to transmit) the DL data of the present disclosure based on the DL assignment available to the UE.

[0165] The data unit of the present disclosure undergoes physical layer processing at the transmitting side before being transmitted via the radio interface, and the radio signal carrying the data unit of the present disclosure undergoes physical layer processing at the receiving side. For example, the MAC PDU including the PDCP PDU according to the present disclosure can undergo physical layer processing as follows.

[0166] Figure 7Examples of physical layer processing at the transmitting side are illustrated.

[0167] The following tables show the mapping of transport channels (TrCHs) and control information to their corresponding physical channels. Specifically, Table 6 specifies the mapping of uplink transport channels to their corresponding physical channels, Table 7 specifies the mapping of uplink control channel information to their corresponding physical channels, Table 8 specifies the mapping of downlink transport channels to their corresponding physical channels, and Table 9 specifies the mapping of downlink control channel information to their corresponding physical channels.

[0168] [Table 6]

[0169]

[0170] [Table 7]

[0171]

[0172] [Table 8]

[0173]

[0174] [Table 9]

[0175]

[0176] [Encoding]

[0177] Data and control flows from / to the MAC layer are encoded to provide transport and control services over the radio transmission links in the PHY layer. For example, transport blocks from the MAC layer are encoded into codewords at the transmitting side. Channel coding schemes are a combination of error detection, error correction, rate matching, interleaving, and mapping of transport channels or control information to / from physical channels.

[0178] In the 3GPP NR system, the following channel coding schemes are used for different types of TrCHs and different control information types.

[0179] [Table 10]

[0180]

[0181] [Table 11]

[0182]

[0183] For transmission of a DL transport block (i.e., a DL MAC PDU) or a UL transport block (i.e., a UL MAC PDU), a transport block CRC sequence is attached to provide error detection for the receiving side. In 3GPP NR system, a low density parity check (LDPC) code is used by a communication device when encoding / decoding UL-SCH and DL-SCH. 3GPP NR system supports two LDPC base graphs (i.e., two LDPC base matrices): LDPC base Figure 1 graph optimized for small transport blocks Figure 2 and LDPC base Figure 1 graph optimized for larger transport blocks Figure 2 . The LDPC base Figure 1 graph or the LDPC base Figure 2 graph is selected based on the size of the transport block and the code rate R. The code rate R is indicated by a modulation and coding scheme (MCS) index IMCS. The MCS index is dynamically provided to a UE by a PDCCH scheduling PUSCH or PDSCH, by a PDCCH activating or (re)initializing a UL configured grant Type 2 or a DL SPS, or by RRC signaling related to UL configured grant Type 1. If the CRC-attached transport block is larger than the maximum code block size for the selected LDPC base graph, the CRC-attached transport block can be segmented into code blocks and an additional CRC sequence is attached to each code block. The maximum code block sizes for the LDPC base Figure 8 graph and the LDPC base graph are 8448 bits and 3480 bits, respectively. If the CRC-attached transport block is not larger than the maximum code block size for the selected LDPC base graph, the CRC-attached transport block is encoded using the selected LDPC base graph. Each code block of the transport block is encoded using the selected LDPC base graph. The LDPC encoded blocks are then individually rate-matched. Code block concatenation is performed to create a codeword for transmission on PDSCH or PUSCH. For PDSCH, up to 2 codewords (i.e., up to 2 transport blocks) can be simultaneously transmitted on PDSCH. PUSCH can be used for transmission of UL-SCH data and layer 1 / 2 control information. Although not shown in

[0184] , layer 1 / 2 control information can be multiplexed with the codeword for UL-SCH data.

[0185] The bits of the codeword are scrambled and modulated to generate a block of complex-valued modulation symbols.

[0186] <Layer mapping>

[0187] The complex-valued modulation symbols of a codeword are mapped to one or more multiple-input multiple-output (MIMO) layers. A codeword can be mapped to at most 4 layers. The PDSCH can carry two codewords, and thus the PDSCH can support at most 8 layer transmission. The PUSCH supports a single codeword, and thus the PUSCH can support at most 4 layer transmission.

[0188] <transform precoding>

[0189] The DL transmission waveform is normal OFDM using a cyclic prefix (CP). For DL, no transform precoding (in other words, discrete Fourier transform (DFT)) is applied.

[0190] The UL transmission waveform is normal OFDM using a CP, where a transform precoding function that performs a DFT spreading can be disabled or enabled. In the 3GPP NR system, for UL, if enabled, transform precoding can be selectively applied. Transform precoding spreads the UL data in a special way to reduce the peak-to-average power ratio (PAPR) of the waveform. Transform precoding is a form of DFT. In other words, the 3GPP NR system supports two options for the UL waveform: one is CP-OFDM (same as the DL waveform), and the other is DFT-s-OFDM. Whether a UE must use CP-OFDM or DFT-s-OFDM is configured by a BS via an RRC parameter.

[0191] <subcarrier mapping>

[0192] Layers are mapped to antenna ports. In DL, for layer-to-antenna port mapping, a transparent manner (non-codebook-based) mapping is supported, and how beamforming or MIMO precoding is performed is transparent to the UE. In UL, for layer-to-antenna port mapping, both non-codebook-based mapping and codebook-based mapping are supported.

[0193] For each antenna port (i.e., layer) used for transmission of a physical channel (e.g., PDSCH, PUSCH), complex-valued modulation symbols are mapped to subcarriers in resource blocks allocated to the physical channel.

[0194] <OFDM modulation>

[0195] The communication apparatus at the transmitting side generates a time-continuous OFDM baseband signal on the subcarrier spacing configuration u and antenna port p for an OFDM symbol l in a TTI for a physical channel by adding a cyclic prefix (CP) and performing an IFFT. For example, for each OFDM symbol, the communication apparatus at the transmitting side can perform an inverse fast Fourier transform (IFFT) on complex-valued modulation symbols mapped to resource blocks in the corresponding OFDM symbol and add a CP on the IFFTed signal to generate an OFDM baseband signal.

[0196] <upconversion>

[0197] The communication apparatus at the transmitting side upconverts the OFDM baseband signal for an antenna port p, a subcarrier spacing configuration u, and an OFDM symbol l to a carrier frequency f0to which the physical channel is assigned to a cell.

[0198] Figure 2 The processors 102 and 202 in the can be configured to perform encoding, scrambling, modulation, layer mapping, transform precoding (for UL), subcarrier mapping, and OFDM modulation. The processors 102 and 202 can control the transceivers 106 and 206 connected to the processors 102 and 202 to upconvert the OFDM baseband signal to a carrier frequency to generate a radio frequency (RF) signal. The RF signal is transmitted to an external apparatus through the antennas 108 and 208.

[0199] Figure 8 Examples of physical layer processing at the receiving side are illustrated.

[0200] The physical layer processing at the receiving side is basically an inverse processing of the physical layer processing at the transmitting side.

[0201] <downconversion>

[0202] The communication apparatus at the receiving side receives the RF signal at the carrier frequency through an antenna. The transceiver 106 and 206 receiving the RF signal at the carrier frequency downconverts the carrier frequency of the RF signal to a baseband to obtain the OFDM baseband signal.

[0203] <OFDM demodulation>

[0204] The communication apparatus at the receiving side separates and obtains complex-valued modulation symbols via the CP. For example, for each OFDM symbol, the communication apparatus at the receiving side removes the CP from the OFDM baseband signal, and performs an FFT on the CP-removed OFDM baseband signal to obtain complex-valued modulation symbols for an antenna port p, a subcarrier spacing u, and an OFDM symbol l.

[0205] <subcarrier demapping>

[0206] The subcarrier demapping is performed on the complex-valued modulation symbols to obtain complex-valued modulation symbols of corresponding physical channels. For example, the processor 102 can obtain complex-valued modulation symbols mapped to subcarriers belonging to a PDSCH from among complex-valued modulation symbols received in a bandwidth part. For another example, the processor 202 can obtain complex-valued modulation symbols mapped to subcarriers belonging to a PUSCH from among complex-valued modulation symbols received in a bandwidth part.

[0207] <transform deprecoding>

[0208] If transform precoding has been enabled for the uplink physical channel, transform deprecoding (e.g., IDFT) is performed on the complex-valued modulation symbols of the uplink physical channel. For the downlink physical channel and the uplink physical channel for which transform precoding is disabled, no transform deprecoding is performed.

[0209] <Layer de-mapping>

[0210] The complex-valued modulation symbols are de-mapped into one or two codewords.

[0211] <De-modulation and de-scrambling>

[0212] The complex-valued modulation symbols of the codeword are de-modulated and de-scrambled into the bits of the codeword.

[0213] <Decoding>

[0214] The codeword is decoded into a transport block. For UL-SCH and DL-SCH, an LDPC base graph is selected according to the size and code rate R of the transport block Figure 1 or an LDPC base graph Figure 2 The codeword can comprise one or more code blocks. Each code block is decoded into a CRC-attached code block or a CRC-attached transport block using the selected LDPC base graph. If code block segmentation of the CRC-attached transport block is performed at the transmitting side, the CRC sequence is removed from each of the CRC-attached code blocks, thereby obtaining the code blocks. The code blocks are concatenated into the CRC-attached transport block. The transport block CRC sequence is removed from the CRC-attached transport block, thereby obtaining the transport block. The transport block is passed to the MAC layer.

[0215] In the above physical layer processing at the transmitting side and the receiving side, time-domain and frequency-domain resources (e.g., OFDM symbols, subcarriers, carrier frequencies) related to subcarrier mapping, OFDM modulation, and frequency up-conversion / down-conversion can be determined based on resource allocation (e.g., UL grant, DL assignment).

[0216] For uplink data transmission, the processor 102 of the present disclosure can apply (or control the transceiver 106 to apply) the above physical layer processing at the transmitting side to a data unit of the present disclosure to wirelessly transmit the data unit. For downlink data reception, the processor 102 of the present disclosure can apply (or control the transceiver 106 to apply) the above physical layer processing at the receiving side to a received radio signal to obtain a data unit of the present disclosure.

[0217] For downlink data transmission, the processor 202 of the present disclosure can apply (or control the transceiver 206 to apply) the above-mentioned physical layer processing at the transmitting side to the data unit of the present disclosure to wirelessly transmit the data unit. For uplink data reception, the processor 202 of the present disclosure can apply (or control the transceiver 206 to apply) the above-mentioned physical layer processing at the receiving side to the received radio signal to obtain the data unit of the present disclosure.

[0218]

[0219] When the upper layer requests the PDCP entity to be established for a radio bearer for Uu or PC5 interface or for groupcast and broadcast NR sidelink communication or for sidelink SRB4, when the first PDCP PDU is received, and there is no corresponding PDCP entity yet, the UE shall establish the PDCP entity for the radio bearer and set the state variables of the PDCP entity to the initial values.

[0220] Upon receiving a PDCP SDU from upper layers, the transmitting PDCP entity shall start the discardTimer associated with this PDCP SDU.

[0221] For a PDCP SDU received from upper layers, the transmitting PDCP entity shall:

[0222] - perform header compression of the PDCP SDU;

[0223] - perform uplink data compression of the PDCP SDU;

[0224] - perform integrity protection and ciphering using TX_NEXT;

[0225] - set the PDCP SN of the resulting PDCP Data PDU to TX_NEXT modulo 2[pdcp-SN-SizeUL];

[0226] - increment TX_NEXT by 1;

[0227] - submit the resulting PDCP Data PDU to lower layers.

[0228] When the discardTimer expires for a PDCP SDU, or successful delivery of a PDCP SDU is confirmed by a PDCP status report, the transmitting PDCP entity shall discard the PDCP SDU and the corresponding PDCP Data PDUs. If the corresponding PDCP Data PDUs have already been submitted to lower layers, the discard is indicated to lower layers.

[0229] ​For SRB, when upper layer requests PDCP SDU discard, PDCP entity shall discard all stored PDCP SDUs and PDCP PDUs.

[0230] <PDCP discard timer enhancement>

[0231] As described above, according to the current NR standard, the PDCP entity manages the discardTimer per SDU. More specifically, when an SDU is received from the upper layer, the PDCP entity starts the discardTimer. If the discardTimer expires, the PDCP entity discards the SDU in the buffer as well as the PDU corresponding to the SDU. Since the PDCP entity considers the SDU whose discardTimer expires as an outdated SDU, there is no reason to store the SDU as well as the PDU corresponding to the SDU in the buffer.

[0232] In the XR service, the application layer aggregates data from multiple devices, and the application layer can receive data from multiple devices using binding. In other words, the PDCP entity can receive aggregated data from the application layer, which receives from multiple devices. In this case, the current discardTimer operation is not sufficient to determine an outdated SDU.

[0233] Figure 9 An example of a mismatch between the validity time of two devices is shown. In particular, in Figure 9 , the two devices include a binding device and a UE.

[0234] Referring to Figure 9 , the binding device generates data and transmits the data to the UE. Then, the UE starts the discardTimer for the data. In this case, between the binding device and the UE, the validity time will be mismatched.

[0235] That is, from the perspective of the binding device, the data is outdated. However, from the perspective of the UE, since the discardTimer for the data is running at the UE side, the data is not outdated.

[0236] If the validity time between the binding device and the UE is mismatched, the UE can unnecessarily transmit the outdated data to the gNB because the discardTimer for the outdated data is running. Therefore, there is a need to synchronize the validity time between the binding device and the UE.

[0237] According to the disclosure, the PDCP entity periodically starts the discardTimer even if the PDCP entity does not receive the SDU from the upper layer. If the PDCP entity receives the SDU from the upper layer after starting the discardTimer, the PDCP entity applies the remaining time of the discardTimer to the received SDU. If the discardTimer expires, the PDCP entity discards the SDU and the PDU corresponding to the SDU.

[0238] First, the PDCP entity is configured with a duration of the discardTimer, a periodicity for starting the discardTimer, and a reference time.

[0239] The periodicity is for starting the discardTimer. The periodicity can be greater than or equal to the duration of the discardTimer. The duration of the discardTimer is a time between a start time of the discardTimer and an expiration time of the discardTimer.

[0240] The reference time is for starting the first discardTimer, and is indicated to start the first discardTimer after establishing the PDCP entity. Preferably, the reference time can be ms or a symbol.

[0241] Instead of the reference time, the PDCP entity can receive an indication for starting the first discardTimer.

[0242] In addition, the reference time is not configured. In this case, upon establishing the PDCP entity, the PDCP entity starts the first discardTimer.

[0243] The duration of the discardTimer, the periodicity, and the reference time can be configured per QoS flow.

[0244] The PDCP entity is established based on the configuration. After establishing the PDCP entity, the PDCP entity starts the first discardTimer based on the reference time even if the PDCP entity does not receive the PDCP SDU. Thereafter, the PDCP entity periodically starts the discardTimer.

[0245] Figure 10 A first example of managing a discard timer according to the disclosure is illustrated.

[0246] Referring to Figure 10 The PDCP entity is established at T1, and the first discard timer is started at T2 after an escape time for the reference time.

[0247] At T3, the first discardTimer expires. After the escape time for periodicity from the time when the first discardTimer is started, at T4, the PDCP entity starts the second discardTimer.

[0248] Figure 11 A second example of managing discard timers according to the present disclosure is shown. In particular, in Figure 11 , it is assumed that the duration, periodicity, and reference time of discardTimer can be configured per QoS flow. That is, QoS flow #1 and QoS flow #2 are mapped to the same PDCP entity. In addition, the duration, periodicity, and reference time of discardTimer are different for QoS flow #1 and QoS flow #2.

[0249] Referring to Figure 11 , at T1, the PDCP entity is established, and at T2, the discardTimer for QoS flow #1 is started after the escape time for the reference time of QoS flow #1. Further, at T3, the PDCP entity starts the discardTimer for QoS flow #2 after the escape time for the reference time of QoS flow #2.

[0250] In Figure 11 , the discardTimer for QoS flow #1 expires at T4, and the discardTimer for QoS flow #2 expires at T5.

[0251] Next, at T6, the PDCP entity starts the discardTimer for QoS flow #2 after the escape time for periodicity of QoS flow #2 from the time when the discardTimer for QoS flow #2 is started.

[0252] Further, at T7, the PDCP entity starts the discardTimer for QoS flow #1 after the escape time for periodicity of QoS flow #1 from the time when the discardTimer for QoS flow #1 is started.

[0253] At T8, the PDCP entity starts the discardTimer for QoS flow #2 after the escape time for periodicity of QoS flow #2 from the time when the previous discardTimer for QoS flow #2 is started.

[0254] If the PDCP entity receives an SDU while a discardTimer is running, the PDCP entity considers the running discardTimer to be associated with the SDU.

[0255] For the case that the duration, periodicity and reference time of the discardTimer can be configured per QoS flow, the PDCP entity should know which QoS flow the received SDU comes from. The QoS flow for the received SDU can be indicated by the upper layer.

[0256] If the discardTimer expires, the PDCP entity discards the SDU and the PDU corresponding to the SDU. In addition, the PDCP entity indicates the discard indication for the PDU to the lower layer.

[0257] On the other hand, after receiving the SDU, the PDCP entity generates the PDU by performing header compression, security procedure (e.g., ciphering and / or integrity protection) and attaching header. After generating the PDU, the PDCP entity submits the PDU to the lower layer.

[0258] If the PDCP entity does not receive any SDU during the discardTimer is running, the PDCP entity increments a failure count value (FCV). If the FCV is greater than or equal to a threshold value, the PDCP entity indicates the indication to the upper layer. The threshold value can be configured by the upper layer. In addition, the threshold value can be configured per QoS flow. This means that multiple FCVs can be managed in the PDCP entity.

[0259] When the PDCP entity receives the SDU during the discardTimer is running before the FCV is greater than or equal to the threshold value, the FCV can be initiated as an initial value (e.g., zero).

[0260] If the upper layer receives the indication, the upper layer declares the radio link failure procedure for the non-3GPP link (e.g., WLAN or Bluetooth). Then, the upper layer can perform the re-establishment of the non-3GPP link. In addition, the upper layer can also perform the radio link failure procedure for the 3GPP link.

[0261] Figure 12 A third example of managing a discard timer according to the present disclosure is illustrated.

[0262] In Figure 12 In the example of FIG. 10, it is assumed that QoS flow #1 and QoS flow #2 are mapped to the same PDCP entity. In addition, the duration, periodicity and reference time of the discardTimer are configured independently for QoS flow #1 and QoS flow #2.

[0263] Referring to Figure 12 In T1, the PDCP entity is established, and in T2, the discardTimer for QoS flow #1 and QoS flow #2 is initiated after the expiration time of the reference time for QoS flow #1 and QoS flow #2.

[0264] At T3, the PDCP entity receives an SDU associated with QoS flow #2. Then, the PDCP entity applies the remaining discardTimer value to the SDU associated with QoS flow #2.

[0265] At T4, the PDCP entity receives an SDU associated with QoS flow #1. Then, the PDCP entity applies the remaining discardTimer value to the SDU associated with QoS flow #1.

[0266] At T5, upon expiry of the discardTimer for QoS flow #2, the PDCP entity discards the SDU associated with QoS flow #2. In this case, the PDCP entity also discards the PDU corresponding to the SDU for QoS flow #2. In addition, the PDCP entity indicates a discard indication to lower layers for the PDU.

[0267] At T6, upon expiry of the discardTimer for QoS flow #1, the PDCP entity discards the SDU associated with QoS flow #1. In this case, the PDCP entity also discards the PDU corresponding to the SDU for QoS flow #1. In addition, the PDCP entity indicates a discard indication to lower layers for the PDU.

[0268] At T7, after the escape time related to the periodicity for QoS flow #2 from the time when the discardTimer for QoS flow #2 is started, the PDCP entity starts the discardTimer for QoS flow #2.

[0269] At T8, the PDCP entity receives an SDU associated with QoS flow #2. Then, the PDCP entity applies the remaining discardTimer value to the SDU associated with QoS flow #2.

[0270] At T9, upon expiry of the discardTimer for QoS flow #2, the PDCP entity discards the SDU associated with QoS flow #2. In this case, the PDCP entity also discards the PDU corresponding to the SDU for QoS flow #2. In addition, the PDCP entity indicates a discard indication to lower layers for the PDU.

[0271] At T10, after the escape time related to the periodicity for QoS flow #1 from the time when the discardTimer for QoS flow #1 is started, the PDCP entity starts the discardTimer for QoS flow #1.

[0272] At T11, after an escape time related to the periodicity for QoS flow #2 from the time when discardTimer for QoS flow #2 is started, the PDCP entity starts discardTimer for QoS flow #2.

[0273] At T12, the PDCP entity receives an SDU associated with QoS flow #2. Then, the PDCP entity applies the remaining discardTimer value to the SDU associated with QoS flow #2.

[0274] At T13, the PDCP entity does not receive an SDU associated with QoS flow #1 while discardTimer for QoS flow #1 is running. In this case, the PDCP entity increments FCV.

[0275] At T14, upon expiry of discardTimer for QoS flow #2, the PDCP entity discards the SDU associated with QoS flow #2. In this case, the PDCP entity also discards the PDU corresponding to the SDU for QoS flow #2. In addition, the PDCP entity indicates a discard indication to lower layers for the PDU.

[0276] Figure 13 A flowchart for managing a discard timer is shown in accordance with the present disclosure.

[0277] In Figure 13 In A05, the UE can establish a PDCP entity. In particular, when establishing the PDCP entity, the UE can receive information about a discard timer for the PDCP entity. If the PDCP entity is configured with two or more Quality of Service (QoS) flows, the discard timer for the PDCP entity is configured for each of the two or more QoS flows.

[0278] Next, in A10, the PDCP entity of the UE can start the discard timer for the PDCP entity at a reference time. Preferably, the discard timer for the PDCP entity is started periodically. In particular, a length of the discard timer for the PDCP entity is less than or equal to a period of a start time of the discard timer for the PDCP entity.

[0279] Next, in A15, the PDCP entity of the UE receives at least one PDCP Service Data Unit (SDU) from an upper layer during a time when the discard timer for the PDCP entity is running.

[0280] Further, in A20, if the discard timer for the PDCP entity expires, the PDCP entity of the UE discards the at least one PDCP SDU.

[0281] Preferably, if any PDCP SDU is not received before the discard timer for the PDCP entity expires, the PDCP entity of the UE increments a failure count value (FCV) by 1. In this case, if the FCV is greater than or equal to a threshold value, the PDCP entity of the UE transmits information related to a radio link failure to an upper layer.

[0282] According to the present disclosure, when the valid time mismatches between the binding device and the UE, the UE can prevent unnecessary transmission for outdated SDUs.

Claims

1. A method for performing operations by a packet data convergence protocol (PDCP) entity of a user equipment (UE) in a wireless communication system, the method comprising: establishing the PDCP entity; starting a discard timer for the PDCP entity at a reference time; receiving at least one PDCP service data unit (SDU) from an upper layer during the discard timer for the PDCP entity is running; and discarding the at least one PDCP SDU based on the discard timer for the PDCP entity expires.

2. The method of claim 1, wherein, The step of establishing the PDCP entity includes receiving information on the discard timer for the PDCP entity.

3. The method of claim 1, wherein, The discard timer for the PDCP entity is started periodically, and wherein a length of the discard timer for the PDCP entity is less than or equal to a period of a start time of the discard timer for the PDCP entity.

4. The method of claim 1, wherein, The PDCP entity is configured with two or more quality of service (QoS) flows, and wherein the discard timer for the PDCP entity is configured for each of the two or more QoS flows. 5.The method of claim 1, further comprising: incrementing a failure count value (FCV) by 1 based on no PDCP SDU is received until the discard timer for the PDCP entity expires; and sending information related to radio link failure to the upper layer based on the FCV is greater than or equal to a threshold value. 6.A user equipment (UE) in a wireless communication system, the UE comprising: at least one transceiver; at least one processor; and at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations for a packet data convergence protocol (PDCP) entity of the UE, the operations comprising: establishing the PDCP entity; starting a discard timer for the PDCP entity at a reference time; receiving at least one PDCP service data unit (SDU) from an upper layer during the discard timer for the PDCP entity is running; and discarding the at least one PDCP SDU based on the discard timer for the PDCP entity expires.

7. The UE of claim 6, wherein, The operation of establishing the PDCP entity includes receiving information on the discard timer for the PDCP entity.

8. The UE of claim 6, wherein, The discard timer for the PDCP entity is started periodically, and wherein a length of the discard timer for the PDCP entity is less than or equal to a period of a start time of the discard timer for the PDCP entity.

9. The UE of claim 6, wherein, The PDCP entity is configured with two or more quality of service (QoS) flows, and wherein the discard timer for the PDCP entity is configured for each of the two or more QoS flows.

10. The UE of claim 6, wherein, The operations further comprise: incrementing a failure count value, FCV, by 1 based on not receiving any PDCP SDUs until expiry of the discard timer for the PDCP entity; and sending information related to radio link failure to the upper layer based on the FCV being greater than or equal to a threshold value.

11. An apparatus for a user equipment, UE, the apparatus comprising: at least one processor; and at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, are operative to cause the at least one processor to perform operations for a packet data convergence protocol, PDCP, entity of the UE, the operations comprising: establishing the PDCP entity; starting a discard timer for the PDCP entity at a reference time; receiving at least one PDCP service data unit, SDU, from an upper layer during the discard timer for the PDCP entity is running; and discarding the at least one PDCP SDU based on expiry of the discard timer for the PDCP entity.

12. A computer-readable storage medium storing at least one computer program comprising instructions that, when executed by at least one processor, are operative to cause the at least one processor to perform operations for a packet data convergence protocol, PDCP, entity of a user equipment, UE, the operations comprising: establishing the PDCP entity; starting a discard timer for the PDCP entity at a reference time; receiving at least one PDCP service data unit, SDU, from an upper layer during the discard timer for the PDCP entity is running; and discarding the at least one PDCP SDU based on expiry of the discard timer for the PDCP entity.

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