Method, apparatus and storage medium for user equipment

Abstract

This UE can perform first random access preamble transmission related to a preamble transmission counter that is set to a first value and transmit an uplink channel on the basis of a random access response thereto. A contention resolution timer can start on the basis of the transmission of the uplink channel. The UE can perform second random access preamble transmission for a random access process on the basis that the contention resolution timer expired. The UE can start a cell DTX non-active period while the contention resolution timer is running, and maintain the preamble transmission counter as the first value on the basis that the contention resolution timer expired.

Description

Methods, devices and storage media by user devices

[0001] This specification relates to wireless communication systems.

[0002] Various devices and technologies, such as machine-to-machine (M2M) communication, machine-type communication (MTC), and smartphones and tablet PCs (personal computers) that require high data transmission rates, are emerging and becoming widespread. Consequently, the amount of data required to be processed on cellular networks is rapidly increasing. To meet this rapidly increasing data processing demand, technologies such as carrier aggregation and cognitive radio are being developed to efficiently utilize more frequency bands, while multi-antenna technology and multi-BS cooperation technology are being developed to increase the data capacity transmitted within a limited frequency range.

[0003] As more and more communication devices demand greater capacity, the need for enhanced mobile broadband (eMBB) communications is emerging, surpassing legacy radio access technology (RAT). Furthermore, massive machine type communication (mMTC), which connects multiple devices and objects to provide diverse services anytime, anywhere, is a key issue to be considered in next-generation communications.

[0004] Additionally, discussions are underway on communication systems designed to accommodate reliability- and latency-sensitive services and user equipment (UE). The introduction of next-generation wireless access technologies is being discussed, including enhanced mobile broadband (eMBB), mMTC, and ultra-reliable and low latency communication (URLLC).

[0005] As the number of services / UEs that a network must support rapidly increases, the need for energy conservation in the network as well as power conservation in the UE is also gradually increasing.

[0006] One technical task of this specification is to provide methods and procedures for network energy conservation.

[0007] Another technical challenge of this specification is to provide a random access procedure for saving network energy.

[0008] The technical tasks that this specification aims to achieve are not limited to the technical tasks mentioned above, and other technical tasks that are not mentioned will be clearly understood by those skilled in the art related to this specification from the detailed description below.

[0009] In one aspect of this specification, a method by a user equipment (UE) is provided.

[0010] In another aspect of the present disclosure, a device is provided. The device includes at least one processor; and at least one memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations for a user equipment (UE).

[0011] In another aspect of the present disclosure, a computer-readable, non-transitory storage medium is provided, wherein the storage medium stores at least one program code comprising instructions that, when executed, cause at least one processor to perform operations for a user equipment (UE).

[0012] The method, or the operations, include: setting a preamble transmission counter for a random access procedure to a first value; performing a first random access preamble transmission for the random access procedure on a cell; receiving a random access response to the first random access preamble transmission; transmitting an uplink channel based on the random access response; starting a contention resolution timer based on transmitting the uplink channel; and performing a second random access preamble transmission for the random access procedure based on expiration of the contention resolution timer, wherein while the contention resolution timer is running, a cell discontinuous transmission (DTX) inactivity period for the cell starts and based on expiration of the contention resolution timer, the preamble transmission counter may be maintained at the first value.

[0013] In another aspect of the present specification, a method by a base station (BS) is provided.

[0014] In another aspect of the present disclosure, a base station (BS) is provided. The BS includes at least one processor; and at least one memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations for the BS.

[0015] The method, or the operations, may include: receiving a first random access preamble from a UE on a cell, associated with a preamble transmission counter set to a first value for a random access procedure; transmitting a random access response to the first random access preamble to the UE; receiving an uplink channel based on the random access response; and attempting to transmit a downlink channel to the UE, the downlink channel indicating successful contention resolution, while a contention resolution timer started when the uplink channel was transmitted is running.

[0016] The above method or operations may further include: the method by the BS or the operations for the BS: receiving, at the UE, a second random access preamble for the random access procedure when the contention resolution timer expires. While the contention resolution timer is running, a cell DTX inactivity period for the cell starts and based on the contention resolution timer expiring, the preamble transmission counter may be maintained at the first value. Based on receiving a signal indicating successful contention resolution before the contention resolution timer expires, the UE may consider the contention resolution to be successful and may consider the random access procedure to be successfully completed.

[0017] In each aspect of this specification, the method by the UE or the operations for the UE may include: monitoring the downlink channel for contention resolution based on the contention resolution timer being running and the cell being within a cell DTX active period.

[0018] In each aspect of this specification, the method by the UE or the actions for the UE may include: not monitoring the downlink channel for contention resolution based on the cell being in the cell DTX inactive period.

[0019] In each aspect of the present specification, the method by the BS or the operations for the BS may include: transmitting a downlink channel for contention resolution on the cell based on the contention resolution timer being running and the cell being within a cell DTX active period.

[0020] In each aspect of the present specification, the method by the BS or the operations for the BS may include: not transmitting the downlink channel for contention resolution on the cell based on the cell being in the cell DTX inactive period.

[0021] In each aspect of this specification, the preamble transmission counter may be incremented based on the expiration of the contention resolution timer without the cell DTX inactivity period starting while the contention resolution timer is running.

[0022] The above problem solving methods are only some of the examples of this specification, and various examples reflecting the technical features of this specification can be derived and understood by a person having ordinary knowledge in the relevant technical field based on the detailed description below.

[0023] According to some implementations of this specification, methods and procedures for energy saving of a network, BS and / or UE may be provided.

[0024] According to some implementations of this specification, a random access procedure may be provided to save network energy.

[0025] The effects according to this specification are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art related to this specification from the detailed description below.

[0026] To aid in understanding implementations of this specification, the accompanying drawings, which are included as part of the detailed description, provide examples of implementations of this specification and, together with the detailed description, illustrate implementations of this specification:

[0027] Figure 1 illustrates an example of a communication system 1 to which implementations of the present specification are applied;

[0028] FIG. 2 is a block diagram illustrating examples of communication devices capable of performing a method according to the present specification;

[0029] FIG. 3 illustrates another example of a wireless device capable of performing implementation(s) of the present specification;

[0030] FIG. 4 illustrates an example of a frame structure available in a 3rd generation partnership project (3GPP) based wireless communication system;

[0031] Figure 5 illustrates a resource grid of slots;

[0032] FIG. 6 illustrates physical channels used in a 3rd generation partnership project (3GPP)-based communication system, which is an example of a wireless communication system, and a signal transmission / reception process using the channels;

[0033] Figure 7 illustrates a random access process that may be applied to implementation(s) of this specification;

[0034] FIG. 8 illustrates a discontinuous reception (DRX) operation that may be applied to implementation(s) of the present specification;

[0035] Figure 9 illustrates a case where a Long DRX cycle and a Short DRX cycle are set;

[0036] FIG. 10 is an example of the operation of a contention resolution timer according to some implementations of this specification;

[0037] Figure 11 illustrates the flow of UE operation according to some implementations of this specification;

[0038] Figure 12 illustrates the flow of BS operation according to some implementations of this specification.

[0039] Hereinafter, implementations according to this specification will be described in detail with reference to the attached drawings. The detailed description provided below, together with the attached drawings, is intended to describe exemplary implementations of this specification and is not intended to represent the only possible implementations of this specification. The detailed description below includes specific details to provide a thorough understanding of this specification. However, one of ordinary skill in the art will appreciate that this specification may be practiced without these specific details.

[0040] In some cases, to avoid ambiguity in the concepts of this specification, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device. Furthermore, identical components are described using the same drawing reference numerals throughout this specification.

[0041] The techniques, devices, and systems described below can be applied to various wireless multiple access systems. Examples of 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 in wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented in wireless technologies such as Global System for Mobile communication (GSM), General Packet Radio Service (GPRS), and Enhanced Data Rates for GSM Evolution (EDGE) (i.e., GERAN). OFDMA can be implemented in wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (WiFi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolved-UTRA). UTRA is part of UMTS (Universal Mobile Telecommunication System), and 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is a part of E-UMTS that uses E-UTRA.3GPP LTE adopts OFDMA for the downlink (DL) and SC-FDMA for the uplink (UL). LTE-A (LTE-advanced) is an evolved form of 3GPP LTE.

[0042] For convenience of explanation, the following description assumes that this specification applies to 3GPP-based communication systems, such as LTE and NR. However, the technical features of this specification are not limited to this. For example, although the detailed description below is based on a mobile communication system corresponding to a 3GPP LTE / NR system, it can also be applied to any other mobile communication system, except for features specific to 3GPP LTE / NR.

[0043] For terms and technologies used in this specification that are not specifically explained, reference may be made to 3GPP-based standard documents, such as 3GPP TS 36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.321, 3GPP TS 36.300 and 3GPP TS 36.331, 3GPP TS 37.213, 3GPP TS 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.214, 3GPP TS 38.300, 3GPP TS 38.304, 3GPP TS 38.331, etc.

[0044] In the examples of this specification described below, the expression "assumes" that a device "assumes" that the entity transmitting the channel transmits the channel in a manner consistent with the "assume." The entity receiving the channel may mean that, under the assumption that the channel was transmitted in a manner consistent with the "assume," the entity receiving the channel receives or decodes the channel in a manner consistent with the "assume."

[0045] In this specification, UE may be fixed or mobile, and includes various devices that communicate with a BS (base station) to transmit and / or receive user data and / or various control information. UE may be called (Terminal Equipment), MS (Mobile Station), MT (Mobile Terminal), UT (User Terminal), SS (Subscribe Station), wireless device, PDA (Personal Digital Assistant), wireless modem, handheld device, etc. In addition, in this specification, BS generally refers to a fixed station that communicates with UE and / or other BS, and exchanges various data and control information with UE and other BS. BS may be called by other terms such as ABS (Advanced Base Station), NB (Node-B), eNB (evolved-NodeB), BTS (Base Transceiver System), Access Point, PS (Processing Server), etc. In particular, the BS in UTRAN is called a Node-B, the BS in E-UTRAN is called an eNB, and the BS in a new radio access technology network is called a gNB. For convenience of explanation, BSs are collectively referred to as BSs below, regardless of the type or version of communication technology.

[0046] In this specification, a node refers to a fixed point that can transmit / receive radio signals by communicating with a UE. Various types of BSs can be used as nodes regardless of their names. For example, BSs, NBs, eNBs, pico-cell eNBs (PeNBs), home eNBs (HeNBs), relays, and repeaters can be nodes. Furthermore, a node may not be a BS. For example, it can be a radio remote head (RRH) or a radio remote unit (RRU). RRHs, RRUs, etc. generally have a lower power level than the BS. Since an RRH or RRU (hereinafter referred to as RRH / RRU) is generally connected to a BS via a dedicated line such as an optical cable, cooperative communication between an RRH / RRU and a BS can be performed more smoothly than cooperative communication between BSs that are generally connected via a wireless line. Each node is equipped with at least one antenna. The antenna may be a physical antenna, an antenna port, a virtual antenna, or an antenna group. A node is also called a point.

[0047] In this specification, a cell refers to a certain geographical area where one or more nodes provide communication services. Therefore, in this specification, communicating with a specific cell may mean communicating with a BS or node that provides communication services to the specific cell. In addition, the downlink / uplink signal of a specific cell refers to a downlink / uplink signal from / to a BS or node that provides communication services to the specific cell. A cell that provides uplink / downlink communication services to a UE is specifically referred to as a serving cell. In addition, the channel state / quality of a specific cell refers to the channel state / quality of a channel or communication link formed between a BS or node that provides communication services to the specific cell and the UE. In a 3GPP-based communication system, a UE can measure a downlink channel state from a specific node using CRS (Cell-specific Reference Signal) resources transmitted by antenna port(s) of the specific node on CRS resources allocated to the specific node and / or CSI-RS (Channel State Information Reference Signal) resources transmitted.

[0048] Meanwhile, 3GPP-based communication systems use the concept of cells to manage radio resources, and cells associated with radio resources are distinguished from cells in geographical areas.

[0049] A "cell" in a geographical area can be understood as the coverage over which a node can provide a service using a carrier, and a "cell" in a radio resource is associated with a bandwidth (BW), which is a frequency range configured by the carrier. Since downlink coverage, which is the range over which a node can transmit a valid signal, and uplink coverage, which is the range over which a node can receive a valid signal from a UE, depend on the carrier carrying the signal, the coverage of a node is also associated with the coverage of the "cell" of the radio resource used by the node. Therefore, the term "cell" can sometimes be used to mean the coverage of a service provided by a node, sometimes a radio resource, and sometimes the range over which a signal using the radio resource can reach with a valid intensity.

[0050] Meanwhile, the 3GPP communication standard uses the concept of a cell to manage radio resources. A "cell" associated with radio resources is defined as a combination of downlink resources (DL resources) and uplink resources (UL resources), i.e., a combination of a DL component carrier (CC) and an UL CC. A cell can be configured with DL resources alone or a combination of DL resources and UL resources. If carrier aggregation is supported, the linkage between the carrier frequency of the DL resources (or DL ​​CC) and the carrier frequency of the UL resources (or UL CC) can be indicated by system information. For example, the combination of DL resources and UL resources can be indicated by a System Information Block Type 2 (SIB2) linkage. Here, the carrier frequency can be the same as or different from the center frequency of each cell or CC. When carrier aggregation (CA) is established, the UE has only one radio resource control (RRC) connection with the network. One serving cell provides non-access stratum (NAS) mobility information during RRC connection establishment / re-establishment / handover, and one serving cell provides security input during RRC connection re-establishment / handover. Such a cell is called a primary cell (Pcell). A Pcell is a cell operating on the primary frequency where the UE performs initial connection establishment procedures or initiates connection re-establishment procedures.Depending on the UE capability, secondary cells (Scells) can be configured to form a set of serving cells together with Pcells. An Scell ​​can be configured after an RRC (Radio Resource Control) connection establishment has been made, and is a cell that provides additional radio resources in addition to the resources of a special cell (SpCell). The carrier corresponding to a Pcell in downlink is called a downlink primary CC (DL PCC), and the carrier corresponding to a Pcell in uplink is called an UL primary CC (UL PCC). The carrier corresponding to an Scell ​​in downlink is called a DL secondary CC (DL SCC), and the carrier corresponding to the Scell ​​in uplink is called an UL secondary CC (UL SCC).

[0051] For dual connectivity (DC) operation, the term special cell (SpCell) refers to a Pcell of a master cell group (MCG) or a primary secondary cell (PSCell) of a secondary cell group (SCG). A SpCell supports PUCCH transmission and contention-based random access and is always activated. An MCG is a group of serving cells associated with a master node (e.g., BS) and consists of a SpCell (Pcell) and optionally one or more Scells. For a UE configured for DC, an SCG is a subset of serving cells associated with a secondary node and consists of a primary secondary cell (PSCell) and zero or more Scells. A PSCell is a primary Scell ​​of an SCG. For a UE in RRC_CONNECTED state that is not configured for CA or DC, there is only one serving cell consisting of Pcells. For a UE in RRC_CONNECTED state that is configured for CA or DC, the term serving cells refers to the set of cells consisting of SpCell(s) and all Scell(s). In DC, two medium access control (MAC) entities are configured in the UE: one for the MCG and one for the SCG.

[0052] For a UE for which CA is set and DC is not set, a Pcell PUCCH group (also referred to as a primary PUCCH group) consisting of a Pcell and zero or more Scells and a Scell ​​PUCCH group (also referred to as a secondary PUCCH group) consisting of only Scell(s) may be set. In the case of an Scell, an Scell ​​(hereinafter referred to as a PUCCH Scell) on which a PUCCH associated with the cell is transmitted may be set. An Scell ​​for which a PUCCH Scell ​​is indicated belongs to an Scell ​​PUCCH group (i.e., a secondary PUCCH group), and PUCCH transmission of the relevant UCI is performed on the PUCCH Scell, and an Scell ​​for which a PUCCH Scell ​​is not indicated or which is a Pcell and is indicated as a cell for PUCCH transmission belongs to a Pcell PUCCH group (i.e., a primary PUCCH group), and PUCCH transmission of the relevant UCI is performed on the Pcell. Hereinafter, if a UE is configured with an SCG and some implementations of this specification related to PUCCH are applied to the SCG, the primary cell may refer to a PSCell of the SCG. If a UE is configured with a PUCCH Scell ​​and some implementations of this specification related to PUCCH are applied to a secondary PUCCH group, the primary cell may refer to a PUCCH Scell ​​of the secondary PUCCH group.

[0053] In addition to the Pcell and PUCCH Scell, the UE can be configured with a PUCCH-sSCell, which is an Scell ​​for PUCCH cell switching. For example, the UE can be provided with a PUCCH-sSCell by the RRC parameter pucch-sSCell. The UE can be provided with a periodic cell switching pattern for PUCCH transmissions by the RRC parameter pucch-sSCellPattern. Each bit of pucch-sSCellPattern corresponds to a slot according to a reference subcarrier spacing (SCS) configuration, and can designate a primary cell (PCell) or PUCCH-sSCell as a cell for PUCCH transmissions during the slot of the reference SCS configuration. The UE does not transmit a PUCCH on a cell among the PCell and the PUCCH-sSCell that is not designated as a cell for PUCCH transmission by the periodic cell switching pattern. When a UE is set to perform PUCCH cell switching based on a dynamic indication by a DCI format, the corresponding DCI format associated with the generation of HARQ-ACK information by the UE may include a PUCCH cell indicator field indicating whether the PUCCH transmission with the HARQ-ACK information by the UE is on the PCell or the PUCCH-sSCell.

[0054] In this specification, the term "PUCCH cell" is used to refer to a cell in which PUCCH resources are configured. A PUCCH cell may be a PCell, a PUCCH Scell, or a PUCCH-sSCell.

[0055] In a wireless communication system, a UE receives information from a base station (BS) via the downlink (DL), and the UE transmits information to the base station via the uplink (UL). The information transmitted and / or received by the BS and UE includes data and various control information, and various physical channels exist depending on the type and purpose of the information they transmit and / or receive.

[0056] 3GPP-based communication standards define downlink physical channels corresponding to resource elements that carry information originating from higher layers, and downlink physical signals corresponding to resource elements that are used by the physical layer but do not carry information originating from higher layers. For example, the physical downlink shared channel (PDSCH), physical broadcast channel (PBCH), and physical downlink control channel (PDCCH) are defined as downlink physical channels, and reference signals and synchronization signals are defined as downlink physical signals. A reference signal (RS), also referred to as a pilot, refers to a signal with a predefined, special waveform that is known to the BS and the UE. For example, the demodulation reference signal (DMRS), the channel state information RS (CSI-RS), and the positioning reference signal (PRS) are defined as downlink reference signals. 3GPP-based communication standards define uplink physical channels corresponding to resource elements that carry information originating from higher layers, and uplink physical signals corresponding to resource elements that are used by the physical layer but do not carry information originating from higher layers.For example, a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a physical random access channel (PRACH) are defined as uplink physical channels, and a demodulation reference signal (DMRS) for uplink control / data signals and a sounding reference signal (SRS) used for uplink channel measurement are defined.

[0057] In this specification, PDCCH (Physical Downlink Control CHannel) refers to a set of time-frequency resources (e.g., resource elements (REs)) that carry DCI (Downlink Control Information), and PDSCH (Physical Downlink Shared CHannel) refers to a set of time-frequency resources that carry downlink data. In addition, PUCCH (Physical Uplink Control CHannel), PUSCH (Physical Uplink Shared CHannel), and PRACH (Physical Random Access CHannel) refer to sets of time-frequency resources that carry UCI (Uplink Control Information), uplink data, and random access signals, respectively (respectively). Hereinafter, the expression that a user equipment transmits / receives a PUCCH / PUSCH / PRACH is used with the same meaning as that uplink control information / uplink data / random access signals are transmitted / received on or through the PUCCH / PUSCH / PRACH, respectively. Additionally, the expression that BS transmits / receives PBCH / PDCCH / PDSCH is used with the same meaning as transmitting broadcast information / downlink control information / downlink data on or through PBCH / PDCCH / PDSCH, respectively.

[0058] In this specification, radio resources (e.g., time-frequency resources) scheduled or configured by the BS to the UE for transmission or reception of PUCCH / PUSCH / PDSCH are also referred to as PUCCH / PUSCH / PDSCH resources.

[0059] Since the communication device receives a synchronization signal (SS), DMRS, CSI-RS, PRS, PBCH, PDCCH, PDSCH, PUSCH, and / or PUCCH in the form of radio signals on a cell, it cannot selectively receive through an RF receiver only radio signals including only a specific physical channel or only a specific physical signal, or selectively receive through an RF receiver only radio signals excluding only a specific physical channel or only a physical signal. In actual operation, the communication device first receives radio signals on a cell through an RF receiver, converts the radio signals, which are RF band signals, into baseband signals, and decodes a physical signal and / or a physical channel within the baseband signals using one or more processors. Thus, in some implementations of the present specification, not receiving a physical signal and / or a physical channel may not actually mean that the communication device does not receive wireless signals containing the physical signal and / or physical channel at all, but rather that it does not attempt to recover the physical signal and / or physical channel from the wireless signals, e.g., does not attempt to decode the physical signal and / or the physical channel.

[0060] As more and more communication devices demand greater communication capacity, the need for improved mobile broadband communication over existing radio access technology (RAT) is emerging. Furthermore, massive MTC, which connects numerous devices and objects to provide diverse services anytime, anywhere, is also a key issue to be considered in next-generation communications. Furthermore, communication system design that considers reliability and latency-sensitive services / UEs is being discussed. The introduction of next-generation RATs that take advanced mobile broadband communication, massive MTC, and URLLC (Ultra-Reliable and Low Latency Communication) into account is currently under discussion. 3GPP is currently conducting studies on next-generation mobile communication systems beyond EPC. For convenience, this technology is referred to as new RAT (NR) or 5G RAT, and a system that uses or supports NR is referred to as an NR system.

[0061] FIG. 1 illustrates an example of a communication system 1 to which implementations of the present specification are applied. Referring to FIG. 1, the communication system (1) applied to the present specification includes a wireless device, a BS, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (e.g., 5G NR (New RAT), LTE (e.g., E-UTRA)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Things) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and may be implemented in the form of a Head-Mounted Device (HMD), a Head-Up Display (HUD) installed in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, digital signage, a vehicle, a robot, etc. Mobile devices may include a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), a computer (e.g., a laptop, etc.), etc. Home appliances may include a TV, a refrigerator, a washing machine, etc. IoT devices may include sensors, smart meters, etc. For example, a BS or network may also be implemented as a wireless device, and a specific wireless device may act as a BS / network node to other wireless devices.

[0062] Wireless devices (100a to 100f) can be connected to a network (300) via a BS (200). Artificial Intelligence (AI) technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) via a network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the BS (200) / network (300), but can also communicate directly (e.g., sidelink communication) without going through the BS / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to Everything) communication). In addition, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0063] Wireless communication / connection (150a, 150b) can be performed between wireless devices (100a~100f) / BS (200) - BS (200) / wireless devices (100a~100f). Here, the wireless communication / connection can be performed through various wireless access technologies (e.g., 5G NR) for uplink / downlink communication (150a) and sidelink communication (150b) (or D2D communication). Through the wireless communication / connection (150a, 150b), the wireless device and the BS / wireless device can transmit / receive wireless signals to / from each other. To this end, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes can be performed based on various proposals of this specification.

[0064] FIG. 2 is a block diagram illustrating examples of communication devices capable of performing a method according to the present specification. Referring to FIG. 2, a first wireless device (100) and a second wireless device (200) can transmit and / or receive wireless signals via various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (100), the second wireless device (200)} can correspond to {the wireless device (100x), the BS (200)} and / or {the wireless device (100x), the wireless device (100x)} of FIG. 1.

[0065] A first wireless device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement functions, procedures, and / or methods described / suggested below. For example, the processor (102) may process information in the memory (104) to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceivers (106). In addition, the processor (102) may receive a wireless signal including second information / signals via the transceivers (106), and then store information obtained from signal processing of the second information / signals in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including commands for performing the procedures and / or methods described / proposed below. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In this specification, a wireless device may also mean a communication modem / circuit / chip.

[0066] The second wireless device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the functions, procedures, and / or methods described / suggested below. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). In addition, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including commands for performing the procedures and / or methods described / proposed below. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In this specification, a wireless device may also mean a communication modem / circuit / chip.

[0067] The wireless communication technology implemented in the wireless device (100, 200) of the present specification may include not only LTE, NR, and 6G, but also Narrowband Internet of Things for low-power communication. At this time, for example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device (XXX, YYY) of the present specification may perform communication based on LTE-M technology. At this time, for example, LTE-M technology may be an example of LPWAN technology, and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device (XXX, YYY) of the present specification can include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create personal area networks (PAN) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0068] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a service data adaptation protocol (SDAP) layer). One or more processors (102, 202) may 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 this specification. One or more processors (102, 202) may generate messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in this specification. One or more processors (102, 202) may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in this specification, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) may receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in this specification.

[0069] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (102, 202) may 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) may be included in one or more processors (102, 202). The functions, procedures, proposals, and / or methods disclosed in this specification may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the functions, procedures, suggestions and / or methods disclosed in this specification may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) and executed by one or more processors (102, 202). The functions, procedures, suggestions and / or methods disclosed in this specification may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0070] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0071] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as described in the methods and / or flowcharts of this specification, to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as described in the functions, procedures, proposals, methods and / or flowcharts of this specification, from one or more other devices. For example, one or more transceivers (106, 206) may be coupled to one or more processors (102, 202) and may transmit and / or receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be coupled to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and / or receive user data, control information, wireless signals / channels, or the like, as referred to in the functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this specification, via one or more antennas (108, 208). In this specification, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) may convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals for processing using one or more processors (102, 202).One or more transceivers (106, 206) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0072] FIG. 3 illustrates another example of a wireless device capable of performing implementation(s) of the present specification. Referring to FIG. 3, the wireless device (100, 200) corresponds to the wireless device (100, 200) of FIG. 2 and may be composed of various elements, components, units / units, and / or modules. For example, the wireless device (100, 200) may include a communication unit (110), a control unit (120), a memory unit (130), and additional elements (140). The communication unit may include a communication circuit (112) and a transceiver(s) (114). For example, the communication circuit (112) may include one or more processors (102, 202) and / or one or more memories (104, 204) of FIG. 2. For example, the transceiver(s) (114) may include one or more transceivers (106, 206) and / or one or more antennas (108, 208) of FIG. 2. The control unit (120) is electrically connected to the communication unit (110), the memory unit (130), and the additional elements (140) and controls the overall operation of the wireless device. For example, the control unit (120) may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit (130). In addition, the control unit (120) may transmit information stored in the memory unit (130) to an external device (e.g., another communication device) via a wireless / wired interface through the communication unit (110), or store information received from an external device (e.g., another communication device) via a wireless / wired interface in the memory unit (130).

[0073] The additional element (140) may be configured in various ways depending on the type of the wireless device. For example, the additional element (140) may include at least one of a power unit / battery, an input / output (I / O) unit, a driving unit, and a computing unit. Although not limited thereto, the wireless device may be implemented in the form of a robot (Fig. 1, 100a), a vehicle (Fig. 1, 100b-1, 100b-2), an XR device (Fig. 1, 100c), a portable device (Fig. 1, 100d), a home appliance (Fig. 1, 100e), an IoT device (Fig. 1, 100f), a UE for digital broadcasting, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, an AI server / device (Fig. 1, 400), a BS (Fig. 1, 200), a network node, etc. Wireless devices may be mobile or stationary depending on the use / service.

[0074] In FIG. 3, various elements, components, units / parts, and / or modules within the wireless device (100, 200) may be entirely interconnected via a wired interface, or at least some may be wirelessly connected via a communication unit (110). For example, within the wireless device (100, 200), the control unit (120) and the communication unit (110) may be wired, and the control unit (120) and a first unit (e.g., 130, 140) may be wirelessly connected via the communication unit (110). In addition, each element, component, unit / part, and / or module within the wireless device (100, 200) may further include one or more elements. For example, the control unit (120) may be composed of one or more processor sets. For example, the control unit (120) may be composed of a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing processor, a memory control processor, etc. As another example, the memory unit (130) may be composed of RAM (Random Access Memory), DRAM (Dynamic RAM), ROM (Read Only Memory), flash memory, volatile memory, non-volatile memory, transitory memory, non-transitory memory, and / or a combination thereof.

[0075] In this specification, at least one memory (e.g., 104 or 204) can store instructions or programs that, when executed, cause at least one processor operably connected to the at least one memory to perform operations according to some embodiments or implementations of the present specification.

[0076] In this specification, a computer-readable (non-volatile or non-transitory) storage medium can store at least one instruction or computer program, which when executed by at least one processor causes the at least one processor to perform operations according to some embodiments or implementations of this specification.

[0077] In this specification, a processing device or apparatus may include at least one processor and at least one computer memory operatively connected to the at least one processor. The at least one computer memory may store instructions or programs, which, when executed, cause at least one processor operatively connected to the at least one memory to perform operations according to some embodiments or implementations of the present specification.

[0078] In this specification, a computer program may be stored in at least one computer-readable (non-volatile) storage medium and may include program code that, when executed, performs operations according to some implementations of the present specification or causes at least one processor to perform operations according to some implementations of the present specification. The computer program may be provided in the form of a computer program product. The computer program product may include at least one computer-readable (non-volatile) storage medium.

[0079] A communications device of the present specification comprises at least one processor; and at least one computer memory operably connected to said at least one processor and storing instructions that, when executed, cause said at least one processor to perform operations according to the example(s) of the present specification described below.

[0080] Figure 4 illustrates an example of a frame structure available in a 3GPP-based wireless communication system.

[0081] The structure of the frame in Fig. 4 is merely an example, and the number of subframes, the number of slots, and the number of symbols in the frame can be varied. In an NR system, OFDM numerology (e.g., subcarrier spacing (SCS)) may be set differently between multiple cells aggregated to a single UE. Accordingly, the (absolute time) duration of a time resource (e.g., a subframe, a slot, or a transmission time interval (TTI)) consisting of the same number of symbols may be set differently between the aggregated cells. Here, the symbol may include an OFDM symbol (or a cyclic prefix - orthogonal frequency division multiplexing (CP-OFDM) symbol), an SC-FDMA symbol (or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol). In this specification, the terms symbol, OFDM-based symbol, OFDM symbol, CP-OFDM symbol, and DFT-s-OFDM symbols are interchangeable.

[0082] Referring to Figure 4, in the NR system, uplink and downlink transmissions are organized into frames. Each frame is T f= (△f max *N f / 100)*T c = 10 ms duration, divided into two half-frames of 5 ms each. Here, T is the basic time unit for NR. c = 1 / (△f max *N f ) and △f max = 480*10 3 Hz, and N f =4096. For reference, T is the basic time unit for LTE. s = 1 / (△f ref *N f,ref ) and △f ref = 15*10 3 Hz, and N f,ref =2048. T s Wow T c is a constant κ = T s / T c = 64 relationship. Each half-frame consists of 5 subframes, and the duration of a single subframe is T. sf is 1ms. Subframes are further divided into slots, and the number of slots in a subframe depends on the subcarrier spacing. Each slot consists of 14 or 12 OFDM symbols based on the cyclic prefix. For a normal cyclic prefix (CP), each slot consists of 14 OFDM symbols, and for an extended CP, each slot consists of 12 OFDM symbols. The numerology is exponentially scalable with a subcarrier spacing △f = 2. u *Depends on 15 kHz. The following table shows the subcarrier spacing for regular CP △f = 2. u *Number of OFDM symbols per slot at 15 kHz (N) slot symb ), number of slots per frame (N frame,uslot ) and the number of slots per subframe (N subframe,u slot ) is shown.

[0083]

[0084] The following table shows the subcarrier spacing for extended CP △f = 2. u *Indicates the number of OFDM symbols per slot, the number of slots per frame, and the number of slots per subframe at 15 kHz.

[0085]

[0086] For a subcarrier spacing setting u, slots are n in increasing order within a subframe. u s ∈ {0, ..., nsubframe,u slot - 1} and n in increasing order within the frame u s,f ∈ {0, ..., n frame,u slot - Numbered as 1}.

[0087] Figure 5 illustrates the resource grid of a slot. A slot contains multiple symbols (e.g., 14 or 12) in the time domain. For each numeral (e.g., subcarrier spacing) and carrier, a common resource block (CRB) N is indicated by higher layer signaling (e.g., radio resource control (RRC) signaling). start,u grid Starting from,N size,u grid,x *N RB sc Dog subcarriers and N subframe,u symb A resource grid of OFDM symbols is defined, where N size,u grid,xis the number of resource blocks (RBs) in the resource grid, and the subscript x is DL for downlink and UL for uplink. N RB sc is the number of subcarriers per RB, and in 3GPP-based wireless communication systems, N RB sc is typically 12. For a given antenna port p, subcarrier spacing configuration u, and transmission direction (DL or UL), there is one resource grid. The carrier bandwidth N for subcarrier spacing configuration u size,u grid is given to the UE by higher layer parameters (e.g., RRC parameters) from the network. Each element in the resource grid for antenna port p and subcarrier spacing configuration u is called a resource element (RE), and one 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 indicating the symbol position relative to a reference point in the time domain. In an NR system, an RB is defined by 12 consecutive subcarriers in the frequency domain. In an NR system, RBs can be classified into common resource blocks (CRBs) and physical resource blocks (PRBs). CRBs are numbered upwards from 0 in the frequency domain for the subcarrier spacing configuration u. The center of subcarrier 0 of CRB 0 for the subcarrier spacing configuration u coincides with 'Point A', which is a common reference point for the resource block grids. PRBs for subcarrier spacing u are defined within the bandwidth part (BWP) and range from 0 to N. size,u BWP,i -1, where i is the number of the bandwidth part. Common resource block n u CRBand bandwidth part i within physical resource block n PRB The relationship between the two is as follows: n u PRB = n u CRB +N start,u BWP,i , here N start,u BWP,i is a common resource block (BRB) whose bandwidth part starts relative to CRB 0. A BWP comprises multiple consecutive RBs in the frequency domain. For example, a BWP may be a given numeral u within a BWP i on a given carrier. i A subset of contiguous CRBs defined for a carrier. A carrier may include up to N (e.g., 5) BWPs. A UE may be configured to have one or more BWPs on a given component carrier. Data communication is performed through the activated BWPs, and only a predetermined number (e.g., 1) of BWPs configured for the UE may be activated on the carrier.

[0088] For each serving cell in a set of DL BWPs or UL BWPs, the network configures at least an initial DL BWP and one (if the serving configuration is configured with uplink) or two (if supplementary uplink is used) initial UL BWPs. The network may also configure additional UL and DL BWPs for the serving cell. For each DL BWP or UL BWP, the UE is provided with the following parameters for the serving cell: i) subcarrier spacing, ii) cyclic prefix, and iii) N start BWP = Offset RB with the assumption of 275 set and length L RB CRBN provided by the RRC parameter locationAndBandwidth, which indicates the resource indicator value (RIV). start BWP=O carrier +RB start and the number of contiguous RBs N size BWP =L RB , and the subcarrier spacing is provided by the RRC parameter offsetToCarrierO carrier ; an index within the set of DL BWPs or UL BWPs; a set of BWP-common parameters and a set of BWP-specific parameters.

[0089] Virtual resource blocks (VRBs) are defined within the bandwidth part and are numbered from 0 to N. size,u BWP,i Numbered from -1, where i is the number of the bandwidth part. VRBs are mapped to physical resource blocks (PRBs) according to interleaved or non-interleaved mapping. In some implementations, for non-interleaved VRB-to-PRB mapping, VRB n may be mapped to PRB n.

[0090] NR frequency bands are defined by two types of frequency ranges, FR1 and FR2, with FR2 also referred to as millimeter wave (mmW). The following table lists the frequency ranges in which NR can operate.

[0091]

[0092] Figure 6 illustrates physical channels used in a 3GPP-based communication system, which is an example of a wireless communication system, and a signal transmission / reception process using the channels.

[0093] When a UE is powered on again after being powered off or has been disconnected from a wireless communication system, it first searches for a suitable cell to camp on (search cell) and performs an initial cell search process, such as synchronizing with the cell or the BS of the cell (S11). During the initial cell search process, the UE receives a synchronization signal block (SSB) (also called an SSB / PBCH block) from the BS. The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The UE synchronizes with the BS based on the PSS / SSS and obtains information such as a cell identity (ID). In addition, the UE can obtain broadcast information within the cell based on the PBCH. Meanwhile, the UE can check the downlink channel status by receiving a downlink reference signal (DL RS) during the initial cell search process.

[0094] A UE that has completed initial cell search can camp on the cell. After camping on the cell, the UE monitors the PDCCH on the cell and receives the PDSCH based on the downlink control information (DCI) carried by the PDCCH to obtain more specific system information (S12).

[0095] Thereafter, the UE may perform a random access procedure to complete access to the BS (S13 to S16). For example, in the random access procedure, the UE may transmit a preamble through a physical random access channel (PRACH) (S13) and receive a random access response (RAR) to the preamble through a PDCCH and a corresponding PDSCH (S14). If reception of the RAR for the UE fails, the UE may retry transmitting the preamble. In the case of contention-based random access, a contention resolution procedure (S16) may be performed, including transmission of a PUSCH based on UL resource allocation included in the RAR (S15) and reception of a PDCCH and a corresponding PDSCH.

[0096] The UE, which has performed the procedure described above, can then perform reception of PDCCH / PDSCH (S17) and transmission of PUSCH / PUCCH (S18) as a general uplink / downlink signal transmission process. The control information that the UE transmits to the BS is collectively referred to as uplink control information (UCI). UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and reQuest Acknowledgement / Negative-ACK) (also referred to as HARQ-ACK), scheduling request (SR), channel state information (CSI), etc. CSI may include a channel quality indicator (CQI), a precoding matrix indicator (PMI), and / or a rank indicator. UCI is generally transmitted through PUCCH, but may be transmitted through PUSCH when control information and traffic data must be transmitted simultaneously. Additionally, based on a request / instruction from the network, the UE can transmit UCI aperiodically via PUSCH.

[0097] Figure 7 illustrates a random access process that may be applied to implementation(s) of the present specification. In particular, Figure 7(a) illustrates a four-step random access process, and Figure 7(b) illustrates a two-step random access process.

[0098] The random access procedure can be used for various purposes, such as initial access, uplink synchronization adjustment, resource allocation, handover, reconfiguration of radio links after radio link failure, and position measurement. The random access procedure is classified into a contention-based procedure and a dedicated (i.e., non-contention-based) procedure. The contention-based random access procedure is commonly used, including initial access, while the dedicated random access procedure is used for handovers, when downlink data arrives at the network, and to reestablish uplink synchronization in the case of position measurement. In the contention-based random access procedure, the UE randomly selects a random access (RA) preamble. Therefore, multiple UEs can transmit the same RA preamble simultaneously, necessitating subsequent contention resolution. In contrast, in the dedicated random access procedure, the UE uses an RA preamble uniquely assigned to the UE by the BS. Therefore, the UE can perform the random access procedure without collisions with other UEs.

[0099] Referring to Fig. 7(a), the contention-based random access process includes the following four steps. Hereinafter, the messages transmitted in steps 1 through 4 may be referred to as Msg1 through Msg4, respectively.

[0100] - Step 1: The UE transmits an RA preamble via PRACH.

[0101] - Step 2: The UE receives a random access response (RAR) from the BS via PDSCH.

[0102] - Step 3: The UE transmits UL data to the BS via PUSCH based on the RAR. Here, the UL data includes layer 2 and / or layer 3 messages.

[0103] - Step 4: The UE receives a contention resolution message from the BS via PDSCH.

[0104] A UE can receive information about random access from a BS through system information. For example, information about RACH occasions associated with SSBs on a cell can be provided through the system information. The UE can select an SSB among the SSBs received on the cell whose reference signal received power (RSRP) measured based on the SSB exceeds a threshold, and transmit an RA preamble through a PRACH associated with the selected SSB. For example, if random access is required, the UE transmits Msg1 (e.g., preamble) to the BS on the PRACH. The BS can distinguish each random access preamble through the time / frequency resource (RA Occasion, RO) on which the random access preamble was transmitted and the random access preamble index (Preamble Index, PI). When the BS receives a random access preamble from the UE, the BS transmits a RAR message to the UE on the PDSCH. To receive a RAR message, the UE monitors an L1 / L2 control channel (PDCCH) CRC-masked with a Random Access-RNTI (RA-RNTI), which contains scheduling information for the RAR message, within a preset time window, i.e., an RAR window (e.g., ra-ResponseWindow). The length of the RAR window can be set by higher layer signaling, and the RAR window can start at a specific timing after a PRACH transmission (e.g., a first symbol of an earliest control resource set (CORESET) of a type-1 PDCCH common search space starting at least one symbol after a PRACH time corresponding to the PRACH transmission). When the UE receives scheduling information through a PDCCH masked with an RA-RNTI, the UE can receive the RAR message from a PDSCH indicated by the scheduling information.Afterwards, the UE determines whether the RAR message contains an RAR for itself. Whether an RAR for itself exists can be determined by checking whether a RAPID (Random Access Preamble ID) exists in the preamble transmitted by the UE. The index and RAPID of the preamble transmitted by the UE may be identical. The RAR includes a corresponding random access preamble index, timing offset information for UL synchronization (e.g., timing advance command (TAC), UL scheduling information for Msg3 transmission (e.g., UL grant), and UE temporary identification information (e.g., Temporary-C-RNTI, TC-RNTI). The UE receiving the RAR transmits Msg3 through the PUSCH according to the UL scheduling information and timing offset value in the RAR. Msg3 may include the ID of the UE (or the global ID of the UE). In addition, Msg3 may include information related to an RRC connection request for initial access to the network (e.g., an RRCSetupRequest message). After receiving Msg3, the BS transmits Msg4, which is a contention resolution message, to the UE. If the UE receives the contention resolution message and the contention is successfully resolved, the TC-RNTI is changed to the C-RNTI. Msg4 includes the ID of the UE. And / or RRC connection related information (e.g., RRCSetup message) may be included. If the information transmitted via Msg3 does not match the information received via Msg4, or if Msg4 is not received for a certain period of time, the UE may consider contention resolution to have failed and retransmit Msg3.

[0105] Meanwhile, the dedicated random access process includes the following three steps. Hereinafter, the messages transmitted in steps 0 to 2 may be referred to as Msg0 to Msg2, respectively. The dedicated random access process may be triggered in the UE by the BS using a PDCCH (hereinafter, PDCCH order) for commanding the transmission of an RA preamble.

[0106] - Step 0: BS allocates RA preamble to UE through dedicated signaling.

[0107] - Step 1: The UE transmits an RA preamble via PRACH.

[0108] - Step 2: The UE receives RAR via PDSCH from the BS.

[0109] The operation of steps 1 and 2 of the dedicated random access process may be identical to steps 1 and 2 of the contention-based random access process.

[0110] NR systems may require lower latency than traditional systems. Furthermore, a four-step random access process may be undesirable, especially for latency-sensitive services such as URLLC. A low-latency random access process may be required in various scenarios within NR systems. When implementing implementations of this specification in conjunction with a random access process, implementations of this specification may be implemented in conjunction with the following two-step random access process to reduce the latency of the random access process.

[0111] Referring to Fig. 7(b), the two-step random access process may be composed of two steps: transmission of MsgA from a UE to a BS and transmission of MsgB from the BS to the UE. The MsgA transmission may include transmission of an RA preamble via a PRACH and transmission of an UL payload via a PUSCH. In the MsgA transmission, the PRACH and PUSCH may be transmitted using time division multiplexing (TDM). Alternatively, in the MsgA transmission, the PRACH and PUSCH may be transmitted using frequency division multiplexing (FDM).

[0112] A BS that receives MsgA may transmit MsgB to the UE. MsgB may include an RAR for the UE. After transmitting MsgA, the UE monitors a response from the network within a time window for monitoring the RAR for a two-step random access procedure. The length of the time window may be set by higher layer signaling, and the time window may start at a specific timing after the MsgA transmission (e.g., the first symbol of the earliest CORESET of the Type-1 PDCCH common search space that starts at least one symbol after the last symbol of the PUCCH epoch corresponding to the PRACH transmission of the MsgA transmission).

[0113] An RRC connection request related message (e.g., an RRCSetupRequest message) requesting to establish a connection between the RRC layer of the BS and the RRC layer of the UE may be transmitted in the payload of MsgA. In this case, MsgB may be used to transmit RRC connection related information (e.g., an RRCSetup message). Alternatively, the RRC connection request related message (e.g., an RRCSetupRequest message) may be transmitted via a PUSCH transmitted based on a UL grant in MsgB. In this case, the RRC connection related information (e.g., an RRCSetup message) related to the RRC connection request may be transmitted via a PDSCH associated with the PUSCH transmission after the PUSCH transmission based on MsgB.

[0114] In relation to contention resolution of the random access process, a contention resolution timer may be set. For example, the BS may transmit an initial value for the contention resolution timer via upper layer signaling to the cell. When a UE that has received a RACH configuration including parameters regarding the contention resolution timer transmits Msg3, the contention resolution timer is started or restarted at the first symbol after the end of the Msg3 transmission or at the first symbol after the end of all repetitions of the Msg3 transmission if the Msg3 transmission is scheduled for PUSCH repetition. The UE monitors the PDCCH while the contention resolution timer is running. If a C-RNTI MAC control element (CE) was included in Msg3 and a PDCCH received by the UE while the contention resolution timer is running is addressed to the C-RNTI, the UE may consider the contention resolution successful, stop the contention resolution timer, discard the TC-RNTI, and consider the random access process to be successfully completed. If a common control channel (CCCH) SDU is included in Msg3, and the PDCCH received by the UE while the contention resolution timer is running is addressed to its TC-RNTI, and the MAC PDU carried by the PDSCH scheduled by the PDCCH is successfully decoded, the UE can stop the contention resolution timer.If the above MAC PDU includes a UE Contention Resolution Identity MAC CE and the UE Contention Resolution Identity in the UE Contention Resolution Identity MAC CE matches the CCCH SDU transmitted in Msg3, the UE may consider the contention resolution to be successful, discard the TC-RNTI, and consider this random access process to be successfully completed. If, while the above contention resolution timer is running (i.e., before the above contention resolution timer expires), the UE does not receive a PDCCH addressed to the C-RNTI in the C-RNTI MAC CE transmitted via Msg3, or does not receive a PDCCH addressed to its TC-RNTI, or does not successfully decode a MAC PDU in a PDSCH corresponding to the PDCCH addressed to its TC-RNTI, or if the MAC PDU is successfully decoded but the UE contention resolution identifier in the MAC PDU does not match a CCCH SDU transmitted via Msg3, the UE may consider the contention resolution to be unsuccessful. If the contention resolution is considered to be unsuccessful, the UE flushes the HARQ buffer used for transmission of the MAC PDU in the Msg3 buffer and increments the PREAMBLE_TRANSMISSION_COUNTER by 1. If PREAMBLE_TRANSMISSION_COUNTER =preambleTransMax+ 1: The MAC layer of the UE can notify the upper layer (e.g., RRC layer) of a random access problem.If that random access process does not complete (e.g. PREAMBLE_TRANSMISSION_COUNTER <preambleTransMax+ 1면), UE는 (상기 임의 접속 과정이 4-단계 임의 접속 과정인 경우) Msg1 전송을 위한 임의 접속 자원 선택 과정을 수행하거나 (상기 임의 접속 과정이 2-단계 임의 접속 과정인 경우) MsgA 전송을 위한 임의 접속 자원 선택 과정을 수행할 수 있다.

[0115] In the random access process, PREAMBLE_TRANSMISSION_COUNTER is a UE variable used for the random access process, and when the random access process is initiated, the UE sets PREAMBLE_TRANSMISSION_COUNTER to 1. preambleTransMax is the maximum number of random access preamble transmissions (i.e., Msg1 transmissions) performed before the UE declares failure, and can be provided via higher layer signaling (e.g., RRC signaling). In the case of a 2-step random access process, msgA-TransMax, which is the maximum number of MsgA transmissions performed before the UE switches to a 4-step random access process, can be set separately from preambleTransMax.

[0116] When the upper layer (e.g., RRC layer) of the UE receives a random access problem from the MAC layer, in particular, the MAC of the MCG, it may consider that a radio link failure has been detected for the MCG and take actions such as entering RRC_IDLE, initiating a connection re-establishment process, or notifying the network of the failure detected by the UE.

[0117] Below, the physical channels that can be used in 3GPP-based wireless communication systems are described in more detail.

[0118] The PDCCH carries DCI. For example, the PDCCH (i.e., DCI) carries the transmission format and resource allocation of the downlink shared channel (DL-SCH), resource allocation information for the uplink shared channel (UL-SCH), paging information for the paging channel (PCH), system information on the DL-SCH, resource allocation information for control messages of a layer (hereinafter, upper layer) located above the physical layer in the protocol stacks of the UE / BS, such as a random access response (RAR) transmitted on the PDSCH, transmission power control commands, activation / release of configured scheduling (CS), etc. The DCI that includes resource allocation information for the DL-SCH is also called PDSCH scheduling DCI, and the DCI that includes resource allocation information for the UL-SCH is also called PUSCH scheduling DCI. The DCI includes a cyclic redundancy check (CRC), and the CRC is masked / scrambled with various identifiers (e.g., radio network temporary identifier (RNTI)) depending on the owner or intended use of the PDCCH. For example, if the PDCCH is for a specific UE, the CRC is masked with the UE identifier (e.g., cell RNTI (C-RNTI)). If the PDCCH is for paging, the CRC is masked with the paging RNTI (P-RNTI). If the PDCCH is for system information (e.g., system information block (SIB)), the CRC is masked with the system information RNTI (SI-RNTI). If the PDCCH is for a random access response, the CRC is masked with the random access RNTI (RA-RATI).

[0119] When a PDCCH on one serving cell schedules a PDSCH or PUSCH on another serving cell, this is called cross-carrier scheduling. Cross-carrier scheduling using the carrier indicator field (CIF) can allow the PDCCH of a serving cell to schedule resources on another serving cell. On the other hand, when a PDSCH on a serving cell schedules a PDSCH or PUSCH on the serving cell, this is called self-carrier scheduling. When cross-carrier scheduling is used in a cell, the BS can provide the UE with information about the cell that schedules the cell. For example, the BS can provide the UE with information about whether the serving cell is scheduled by a PDCCH on another (scheduling) cell or by the serving cell, and if the serving cell is scheduled by another (scheduling) cell, which cell signals downlink assignments and uplink grants for the serving cell. In this specification, a cell that carries a PDCCH is called a scheduling cell, and a cell in which transmission of a PUSCH or PDSCH is scheduled by DCI included in the PDCCH, i.e., a cell that carries a PUSCH or PDSCH scheduled by the PDCCH, is called a scheduled cell.

[0120] The PDSCH is a physical layer DL channel for DL ​​data transport. PDSCH carries downlink data (e.g., DL-SCH transport blocks) and employs modulation methods such as Quadrature Phase Shift Keying (QPSK), 16 Quadrature Amplitude Modulation (QAM), 64 QAM, and 256 QAM. Transport blocks (TBs) are encoded to generate codewords. A PDSCH can carry up to two codewords. Scrambling and modulation mapping are performed for each codeword, and the modulation symbols generated from each codeword can be mapped to one or more layers. Each layer is mapped to radio resources along with the DMRS, generating an OFDM symbol signal and transmitting it through the corresponding antenna port.

[0121] A UE must have uplink resources available to it for UL-SCH data transmission, and downlink resources available to it for DL-SCH data reception. Uplink and downlink resources are assigned to the UE through resource allocation by the BS. Resource allocation may include time domain resource allocation (TDRA) and frequency domain resource allocation (FDRA). In this specification, uplink resource allocation is also referred to as uplink grant, and downlink resource allocation is also referred to as downlink assignment. An uplink grant is dynamically received by the UE on the PDCCH or within the RAR, or is semi-persistently configured to the UE by RRC signaling from the BS. A downlink assignment is dynamically received by the UE on the PDCCH, or is semi-persistently configured to the UE by RRC signaling from the BS.

[0122] In UL, the BS can dynamically allocate uplink resources to the UE via PDCCH(s) addressed to a cell radio network temporary identifier (C-RNTI). The UE monitors the PDCCH(s) to find possible uplink grant(s) for UL transmission. In addition, the BS can allocate uplink resources to the UE using a configured grant (CG). Two types of configured grants can be used: Type 1 and Type 2. In Type 1, the BS directly provides the configured uplink grant (including the periodicity) via RRC signaling. For Type 2, the BS can set the period of the RRC-configured uplink grant through RRC signaling, and can signal and activate or deactivate the configured uplink grant through a PDCCH addressed to CS-RNTI (PDCCH addressed to CS-RNTI) addressed to the configured scheduling RNTI (CS-RNTI). For example, for Type 2, a PDCCH addressed to CS-RNTI indicates that the corresponding uplink grant can be implicitly reused according to the period set by RRC signaling until it is deactivated.

[0123] In DL, the BS can dynamically allocate downlink resources to the UE via PDCCH(s) addressed with the C-RNTI. The UE monitors the PDCCH(s) to discover possible downlink assignments. Additionally, the BS can allocate downlink resources to the UE using semi-static scheduling (SPS). The BS can set the period of the configured downlink assignments via RRC signaling, and signal and activate or deactivate the configured downlink assignments via the PDCCH addressed with the CS-RNTI. For example, a PDCCH addressed with the CS-RNTI implicitly indicates that the corresponding downlink assignment can be reused according to the period set by the RRC signaling until it is deactivated.

[0124] A control resource set (CORESET), which is a set of time-frequency resources for which a UE can monitor PDCCH, may be defined and / or configured. A CORESET consists of a set of physical resource blocks (PRBs) with a duration of one to three OFDM symbols. The PRBs constituting the CORESET and the CORESET duration may be provided to the UE via higher layer (e.g., RRC) signaling. Within the configured CORESET(s), a set of PDCCH candidates is monitored according to the corresponding search space sets. In this specification, monitoring implies decoding (aka blind decoding) each PDCCH candidate according to the monitored DCI formats.

[0125] The set of PDCCH candidates monitored by the UE is defined in terms of PDCCH search space sets. The search space set may be a common search space (CSS) set or a UE-specific search space (USS) set. Each CORESET configuration is associated with one or more search space sets, and each search space set is associated with one CORESET configuration.

[0126] A set of PDCCH candidates may be monitored in one or more CORESETs on an active DL BWP on each activated serving cell for which PDCCH monitoring is configured, where monitoring implies receiving each PDCCH candidate and decoding it according to the monitored DCI formats.

[0127] Based on the CORESET / search space set configuration, the UE can monitor PDCCH candidates in one or more SS sets within a slot. The occasions (e.g., time / frequency resources) during which PDCCH candidates are monitored are defined as PDCCH (monitoring) occasions. One or more PDCCH (monitoring) occasions can be configured within a slot.

[0128] UE discontinuous reception (DRX)

[0129] UE uses DRX to reduce power consumption. UE operating based on DRX repeats ON / OFF for reception operation. The features of DRX utilized for the purpose of reducing unnecessary power consumption of UE are as follows. DRX defines a structure for UE in RRC_IDLE state where RRC connection between UE and BS is not established (hereinafter referred to as I-DRX) and a structure for UE in RRC_CONNECTED state where RRC connection between UE and BS is established (hereinafter referred to as C-DRX). Both DRX structures are designed to reduce unnecessary power consumption in other periods by defining a period (e.g., active time period or on-duration period) in which UE can expect reception of DL signals to occur periodically. For reference, in the case of C-DRX, the start position of On-duration occurs periodically in the Rel-16 standard, and the size of the cycle that can be configured at this time (i.e., DRX cycle) can be determined / set through upper layer signaling, such as RRC signaling, provided by the BS to the UE.

[0130] Figure 8 illustrates discontinuous reception (DRX) operation. In particular, Figure 8 illustrates a DRX cycle for a UE in RRC_CONNECTED state.

[0131] Referring to FIG. 8, a DRX cycle consists of an ON period and an Opportunity for DRX. A DRX cycle defines a time interval in which an ON period is periodically repeated, followed by a possible period of inactivity. The ON period represents a time interval during which the UE performs PDCCH monitoring to receive a PDCCH. When DRX is configured, the UE performs PDCCH monitoring during the ON period. If a PDCCH is successfully detected during PDCCH monitoring, the UE starts an inactivity timer and remains awake. On the other hand, if no PDCCH is successfully detected during PDCCH monitoring, the UE enters a sleep state after the ON period ends. Therefore, when DRX is configured, the UE may perform PDCCH monitoring / reception discontinuously in the time domain when performing a process and / or method according to the implementation(s) of this specification. For example, when DRX is configured, the PDCCH reception occasion (e.g., slot having PDCCH search space) in this specification may be configured discontinuously according to the DRX configuration. On the other hand, when DRX is not configured, the UE may perform PDCCH monitoring / reception continuously in the time domain. For example, when DRX is not configured, the PDCCH reception occasion (e.g., slot having PDCCH search space) may be configured continuously. On the other hand, regardless of whether DRX is configured, PDCCH monitoring may be restricted in the time period configured as the measurement gap. DRX configuration information is received via upper layer (e.g., RRC) signaling, and whether DRX is turned on / off is controlled by the DRX command of the MAC layer. When DRX is configured, the UE may perform PDCCH monitoring discontinuously, as illustrated in FIG. 8.

[0132] The following table illustrates the UE processes related to DRX. Referring to the following table, DRX configuration information is received via upper layer (e.g., RRC) signaling, and DRX ON / OFF is controlled by the DRX command of the MAC layer. When DRX is configured, the UE can perform PDCCH monitoring discontinuously, as illustrated in FIG. 8.

[0133]

[0134] Here, MAC-CellGroupConfig contains configuration information required to set MAC parameters for a cell group. MAC-CellGroupConfig may also contain configuration information related to DRX. For example, MAC-CellGroupConfig may contain DRX-related information as follows.

[0135] - Value of drx-onDurationTimer: Sets the duration at the start of the DRX cycle.

[0136] - Value of drx-SlotOffset: Sets the delay before starting drx-onDurationTimer.

[0137] - Value of drx-InactivityTimer: Sets the period after which a PDCCH epoch indicates a new UL or DL ​​transmission to the MAC entity.

[0138] - Value of drxRetransmissionTimerDL (per DL HARQ process except for the broadcast process): Sets the maximum duration until a DL retransmission is received.

[0139] - Value of drxRetransmissionTimerUL (per UL HARQ process): Sets the maximum duration until a grant for UL retransmission is received.

[0140] - Value of drx-HARQ-RTT-TimerDL (per DL HARQ process except for the broadcast process): Sets the maximum period of time after a DL initial transmission is received until a DL assignment for HARQ retransmission is received.

[0141] - Value of drx-HARQ-RTT-TimerUL (per UL HARQ process): Sets the maximum period from when a grant for UL initial transmission is received until a grant for UL retransmission is received.

[0142] - drx-LongCycleStartOffset: Sets the Long DRX cycle and drx-StartOffset, which defines the subframe where the Long and Short DRX cycles start.

[0143] - drx-ShortCycle (optional): Sets the short DRX cycle.

[0144] - drx-ShortCycleTimer (optional): Sets the duration for which the UE should follow the Short DRX cycle. For example, a value in multiples of the Short DRX cycle can be set by drx-CylceTimer. For example, the value of n can correspond to n*drx-ShortCycle.

[0145] A UE may perform PDCCH monitoring on serving cells within a DRX group when the DRX group is within its active time. Here, a DRX group is a group of serving cells configured by RRC and having the same DRX active time. Here, the active time is a total duration for which the UE monitors the PDCCH, and may include an ON period of a DRX cycle, a time for which the UE performs continuous reception while an inactivity timer has not expired, and a time for which the UE performs continuous reception while waiting for a retransmission opportunity. For example, when DRX is configured, the active time for serving cells within a DRX group is i) while drx-onDurationTimer or drx-InactivityTimer configured for the DRX group is running; or ii) while drx-RetransmissionTimerDL or drx-RetransmissionTimerUL is running on any serving cell within the DRX group; or ra-ContentionResoultionTimer or msgB-RsponseWindow is running; or a PDCCH indicating a new transmission addressed to a C-RNTI addressed to the MAC entity of the UE is not received after successful reception of a random access response to a random access preamble that is not selected by the MAC entity among the contention-based random access preambles.

[0146] A UE can be configured with one or more DRX groups via RRC signaling from a BS. For example, if two DRX groups are configured, each serving cell is uniquely assigned to one of the two DRX groups. The DRX parameters drx-onDurationTimer and drx-InactivityTimer are configured separately for each DRX group, and the DRX parameters drx-SlotOffset, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, drx-LongCycleStartOffset, drx-ShortCycle (optional), drx-ShortCycleTimer (optional), drx-HARQ-RTT-TimerDL, and drx-HARQ-RTT-TimerUL are common to the DRX groups. Since each serving cell belongs to only one of the DRX groups, and the DRX parameters drx-onDurationTimer and drx-InactivityTimer are set for each DRX group, and the remaining DRX parameters are common to the DRX groups, it can be said that a serving cell is associated with only one set of DRX parameters.

[0147] Figure 9 illustrates a case where a Long DRX cycle and a Short DRX cycle are set. In particular, Figure 9 illustrates a case where drx-ShortCycleTimer is set to 2.

[0148] A BS can configure a Long DRX cycle and an additional Short DRX cycle that is shorter than the Long DRX cycle. If a Short DRX cycle is not configured, the UE follows the Long DRX cycle. When configuring a Short DRX cycle, the BS sets the duration of the Long DRX cycle to be a positive integer multiple of the Short DRX cycle. The same onDurationTimer value is configured for the Long DRX cycle and the Short DRX cycle. If there is no data activity during the ON period of the Long DRX cycle (e.g., no PDCCH reception), the UE follows the Long DRX cycle as if the Short DRX cycle is not configured. If there is data activity during the ON period of the Long DRX cycle, for example, while drx-onDurationTimer is running, the UE switches to the Short DRX cycle and follows the Short DRX cycle for a certain period of time (e.g., while drx-ShortCycleTimer is running). At this time, the start of the ON period in the Short DRX cycle is determined by drx-StartOffset and drx-SlotOffset, just like the Long DRX cycle. Referring to FIG. 9, if there is no data activity during the time following the Short DRX cycle, for example, if there is no data activity during the period defined by drx-ShortCycleTimer*drx-ShortCycle, the UE switches to the Long DRX cycle after drx-ShortCycleTimer Short DRX cycles.

[0149] Network energy saving and cell DRX / DTX

[0150] Energy conservation of base stations (BSs) is a key consideration in wireless communication systems, including 3GPP, as it can contribute to building eco-friendly networks by reducing carbon emissions and reducing the operational expenditure (OPEX) of telecommunications operators. In particular, the introduction of 5G communications will require higher transmission rates, necessitating BSs to be equipped with more antennas and provide services over wider bandwidths and frequency bands. Consequently, recent studies have shown that BS energy costs have reached up to 20% of total OPEX. This heightened interest in BS energy conservation led to the approval of a new study item, "Study on Network Energy Savings," in 3GPP NR Release 18. For example, to improve the energy saving capability of BS from the perspective of transmission and reception, the study investigates how to achieve dynamic and / or semi-static and finer granularity adaptation of transmission and / or reception to more efficient operation with one or more network energy saving techniques in time, frequency, space and power domains using potential assistance / feedback of UE and potential UE assistance information.

[0151] Hereinafter, when a BS operates in a network energy saving (NES) mode for energy saving (ES), it can mean, for example, that the BS sets multiple OFF intervals (i.e., discontinuous transmixxion (DTX) intervals of the BS) in advance to turn off transmission of a specific DL signal during a specific time interval, and dynamically indicates one of the OFF intervals to indicate that the corresponding DL signal will not be transmitted during the predefined time interval, thereby achieving power consumption savings of the BS and UE. Hereinafter, the NES mode can also mean an operation mode in which power consumption savings of the BS and UE are achieved not only in the domain but also in the frequency domain, such as BWP switching, dynamic resource block (RB) adaptation, etc., and in the spatial domain, for example, when a specific receive antenna port of the BS is turned off semi-statically or dynamically, by the BS not performing transmission and / or reception through the corresponding antenna port.

[0152] As explained above, after the UE initially accesses the BS and enters connected mode, it must continuously perform PDCCH monitoring to check if there is a transmission scheduled for it in each configured search space. However, if this scheduling is not always present, the UE may quickly drain its battery due to unnecessary PDCCH monitoring every time. Therefore, the BS can set the UE to an ON duration during which it must perform PDCCH monitoring and an OFF duration during which it does not need to perform PDCCH monitoring. In other words, the BS can set the UE to connected mode discontinuous reception (C-DRX) to save power. From the BS's perspective, the UE's C-DRX can also help save energy for the BS. For example, during the C-DRX OFF period of a specific UE, the BS does not need to transmit the PDCCH of the specific UE, so the BS can use its resources (e.g., radio resources during the C-DRX OFF period of the specific UE) for other purposes or obtain energy saving (ES) benefits through DTX / DRX. However, since the UE can transmit without restriction as needed on pre-configured resources (e.g., SR, PUCCH, CG PUSCH, etc.) even during the OFF period, the BS must wait for UL reception of the UE, which may be transmitted at any time. In addition, since C-DRX is configured UE-specifically, the DRX cycles or ON / OFF periods between UEs within a cell (or BS) are not aligned.Therefore, if the ON periods of UEs are set in a time division multiplexing (TDM) format, it may be difficult to expect ES gain because the BS cannot sleep for PDCCH transmission for each ON period of each UE within the cell (or BS).

[0153] Therefore, in some implementations of this specification, the BS can save energy by turning OFF transmission / reception of specific signals / channels during inactive periods through cell-specific DTX / DRX configuration with alternating active and inactive periods similar to UE C-DRX. Hereinafter, some implementations of this specification are described regarding cell-specific DTX / DRX operation of a BS that saves energy by turning OFF transmission / reception on the cell during specific time periods or through restricted DTX / DRX that allows transmission / reception of specific signals / channel(s). Also described are some implementations of this specification regarding UE operation for each time period when cell DTX / DRX is combined with DRX operation of UEs within the cell. For convenience, the method(s) by which cell DTX / DRX is combined with the C-DRX operation of the UE and the corresponding operating method(s) are mainly described, but some implementations of this specification can be applied and extended to other DRX operations of the UE (e.g., idle mode DRX) as well as C-DRX.

[0154] The UE monitors the PDCCH during periodic ON periods to check if there is UL / DL to transmit / receive, and when a PDCCH is received, performs DL reception or UL transmission according to the instructions given by the PDCCH. In the case of UL, the UE can wake up from sleep mode and transmit a scheduling request (SR) if there is data to be sent in the UL buffer, regardless of C-DRX. A UE in idle mode periodically performs paging monitoring, and if the UE is not the target UE of the paging, it can operate in idle mode (idle mode DRX (i.e., I-DRX)) which returns to sleep mode. Here, the UE operating in sleep mode can mean performing SR transmission “regardless of the active time determined by C-DRX” or “even in a period other than the active time determined by C-DRX.” In C-DRX operation, a time period consisting of an ON period and an OFF period is repeated, which is called a DRX cycle. The length of a DRX cycle can be defined as from the start of an ON period to before the next ON period, and a DRX cycle can be divided into a Long DRX cycle and a Short DRX cycle. If the length of the DRX cycle becomes longer, if the BS has a PDSCH to send immediately after the end of a specific ON period of the UE, it must wait until the next ON period of the UE, which may increase latency. From the BS's perspective, Since the UE does not transmit periodic CSI (P-CSI) or sounding reference signal (SRS) during the OFF period, the resource (i.e., the resource for P-CSI or SRS transmission) can be allocated to another UE to increase resource utilization.Additionally, the BS may also operate in energy saving mode to save power during the UE's OFF period.

[0155] In relation to C-DRX, the BS may instruct the UE to enter DRX sleep mode directly without operating in active mode until the end of the ON period via the DRX command MAC control element (CE). For example, the BS may instruct the UE to terminate the current active time and directly enter a DRX cycle. If only a Long DRX cycle is configured for the UE, the UE may operate in the Long DRX cycle (based on the DRX command MAC CE). If both a Long DRX cycle and a Short DRX cycle are configured, the UE will immediately enter the Short DRX cycle after receiving the DRX command MAC CE. In addition, if the BS provides a Long DRX command MAC CE, the UE may operate in the Long DRX cycle even if a Short DRX cycle is configured. Additionally, BS can control / change the starting point of the Long DRX cycle via the RRC parameter drx-LongCycleStartOffset, which is used to set the Long DRX cycle and the drx-StartOffset, which defines the subframe in which the Long and Short DRX cycles start. Here, the value of the RRC parameter drx-LongCycleStartOffset is defined in ms units so that the Long DRX cycle can start at the slot boundary. Additionally, the starting point of the ON period can be set at slot level granularity via another RRC parameter drx-SlotOffset. In this case, the relative position of the ON period is defined by applying the slot offset indicated (by drx-SlotOffset) with respect to the reference point indicated by drx-LongCycleStartOffset.BS can utilize ES by aligning ON and OFF periods of multiple UEs within a cell by adjusting the start point of the DRC cycle and the start point of the ON period through the above parameters, but for ES through the dynamic transmission / reception OFF time pattern of BS, a more dynamic offset value indication may be required.

[0156] By waking up the UE only during the ON period and monitoring the presence of PDCCH transmitted to itself through C-DRX configuration, energy can be saved compared to continuously (e.g., at every slot) monitoring the PDCCH. In addition, if the BS has no data to transmit in the upcoming ON period of the UE, the BS can further save the battery of the UE by transmitting a wake-up signal (WUS) before the start of the ON period of the UE to inform the UE that there is no need to wake up in the ON period (i.e., there is no need to start the onDuration timer). Here, for the UE among the UEs configured with C-DRX and that there is no data to transmit / receive in the upcoming ON period, the BS can transmit a WUS that can be transmitted via DCI format 2_6, which is used to notify power saving information outside the DRX active time for one or more UEs, at a WUS occasion configured before the ON period, to indicate to the UE that there is no need to wake up in the current ON period. A UE that receives the above WUS (e.g., wake-up indication via DCI format 2_6) can save more energy because it can continue to sleep without switching to active mode.

[0157] In the following description, UE DRX or C-DRX, I-DRX may mean discontinuous reception from the UE's perspective, cell DRX may mean discontinuous reception from the BS's perspective, and cell DTX may mean discontinuous transmission from the BS's perspective. Cell DRX may mean UL transmission OFF from the UE's perspective, and cell DTX may mean DL reception OFF from the UE's perspective.

[0158] According to the cell DTX / DRX operation, as in the structure similar to the C-DRX of the UE, an active period can be set in which all signals and channels can be transmitted / received without restriction, and a non-active period, which is a time period outside the active period in which transmission / reception of all signals and channels is turned OFF or transmission / reception of only specific signals and channels is performed in a restricted manner (e.g., only transmission / reception of channels / signals such as PDCCH transmission or RACH / SR PUCCH reception is allowed). The cell DTX / DRX configuration can be set and activated only by RRC (i.e., only through RRC signaling), or some parameters for the cell DTX / DRX can be set by RRC and the remaining parameters can be set / indicated and activated through L1 and / or L2 signaling (e.g., (group-common) DCI and / or MAC CE). Information about the location and length (in the time domain) of the active and inactive periods of the cell DTX / DRX can be preset via specific RRC parameters. For example, the start point of the active period can be set via an offset from a specific subframe boundary or a specific system frame number (SFN) value, and the duration can be set via a length-related parameter or timer, etc. In some implementations, the BS can preset multiple parameter or timer candidates and indicate one of the candidates upon activation via L1 and / or L2 signaling. During the cell DTX / DRX active period, transmission / reception of all signals and channels can be possible without any special transmission / reception restrictions, as in the normal operation of the BS.The time interval outside the active interval is basically considered as a non-active interval, and transmission / reception may be restricted except for the preset signal(s) and channel(s), and since the BS can obtain ES gain through the operation of performing only this minimum transmission / reception, the operation when the NES state / mode is ON may be considered in the time interval outside the active interval.

[0159] For example, to reduce the BS downlink transmission / uplink reception active time, the UE can be configured with a periodic cell DTX / DRX pattern (i.e., active and non-active periods). The pattern configuration for cell DTX / DRX can be common to the UEs in the cell. Each serving cell can be configured with a periodic cell DTX pattern by RRC. The BS can configure only cell DTX, only cell DRX, or both for a cell. Cell DTX and cell DRX patterns can be configured and activated separately. Up to N cell DTX / DRX patterns per MAC entity can be configured for different serving cells, where N can be a predefined value. Cell DTX / DRX can be activated / deactivated by RRC signaling or L1 group common signaling (e.g., signaling via group-common PDCCH). The BS can control the cell DTX and cell DRX operation by providing the cell DTX / DRX configuration via RRC signaling. For example, the BS can provide RRC parameters in the cell DTX / DRX configuration regarding a timer for an active period at the beginning of a cell DTX / DRX cycle (e.g., a cell DTX / DRX ON duration timer), a subframe in which the cell DTX / DRX cycle starts, a delay before the active period starts, a cell DTX / DRX cycle period (i.e., a cell DTX / DRX cycle), etc. The active duration of the cell DTX / DRX can be a period of time during which the UE waits to receive PDCCHs or SPS occasions and to transmit an SR or CG. A cycle of the cell DTX / DRX specifies a periodic repetition of an active period followed by an inactive period. The active duration and cycle parameters can be common between the cell DTX and the cell DRX.The BS may configure the C-DRX and the cell DTX / DRX such that there is at least a partial overlap between the C-DRX ON period of the UE and the cell DTX / DRX active period. For example, the BS may configure the C-DRX periodicity of the UE to be an integer multiple of the cell DTX / DRX periodicity, or the cell DTX / DRX periodicity to be an integer multiple of the C-DRX periodicity of the UE.

[0160] In some implementations, cell DTX operation may affect the UE's monitoring activity for PDCCH and configured downlink assignments in RRC_CONNECTED. For a serving cell for which cell DTX is configured and active, a UE (e.g., the MAC entity of the UE) monitors PDCCH on the serving cell if the serving cell is within the cell DTX active period. The cell DTX active period of a serving cell may include the time that a cell DTX / DRX ON duration timer runs for the serving cell. For example, for a serving cell for which cell DTX is configured and active, a UE (e.g., the MAC entity of the UE) may not monitor PDCCH on the serving cell if the serving cell is not within the cell DTX active period or is within the UE C-DRX active period, and may not receive transport blocks on the serving cell according to the configured downlink assignment for SPS (i.e., perform SPS PDSCH reception). That is, when cell DTX is set and activated for a serving cell, the UE may not perform PDCCH monitoring on the serving cell or monitor SPS periods on the serving cell during the cell DTX inactivity period.

[0161] In some implementations, cell DRX operation may control SR and configured uplink grant transmission activity in RRC_CONNECTED. In some scenarios, when cell DRX is configured and activated for a serving cell, the UE (e.g., the MAC entity of the UE) may, in principle, perform CG PUSCH transmissions and (if the serving cell is a PUCCH cell) PUCCH transmissions on the serving cell only within the cell DRX active period. The cell DTX active period of a serving cell may include the time that the cell DTX / DRX ON duration timer runs for the serving cell. For example, if a serving cell for which cell DRX is configured and activated is within a cell DRX inactive period, the UE (e.g., the MAC entity of the UE) does not transmit SR on PUCCH resources for SR (even if the serving cell is a PUCCH cell), does not report periodic CSI on PUCCH (even if the serving cell is a PUCCH cell), and does not report semi-persistent CSI configured on PUSCH of the serving cell. In other words, if cell DRX is configured and activated for a serving cell, the UE may not transmit on CG resources of the serving cell or may not transmit SR on the serving cell during the DRX inactive period.

[0162] [Method #1] UE behavior and timer handling in the cell DTX inactivity interval located / existing after the Msg3 transmission point.

[0163] (1-1) A method of holding the contention resolution (CR) timer and then resuming the CR timer after a cell DTX inactivity period.

[0164] (1-2) A method of maintaining the RACH TX counter value even when the CR timer expires instead of holding the CR timer.

[0165] Figure 10 illustrates examples of the operation of a contention resolution timer according to some implementations of the present specification. In Figure 10, cell A may be a cell in which a CR timer is set.

[0166] As described above, if the UE successfully receives a random access response (RAR) grant within the RAR window after transmitting Msg1, the UE may transmit Msg3 PUSCH based on the information (e.g., the RAR grant). At this time, the UE starts (or restarts, in case of Msg3 retransmission) a CR timer (e.g., ra-ContentionResolutioniTimer) and monitors the PDCCH. If the UE already has a C-RNTI, the BS may transmit a PDCCH (carrying a UL grant or DL ​​assignment) via the C-RNTI of the UE to inform the UE that the random access procedure of the UE has been successful. If the UE does not receive a PDCCH scrambled with the C-RNTI of the UE (i.e., a PDCCH carrying a DCI with a CRC scrambled by the C-RNTI) before the CR timer expires, the CR may be considered as a failure. If the UE does not have a C-RNTI, the BS may transmit Msg4 including a contention resolution identifier MAC CE of the UE to inform the UE that the random access procedure of the UE is successful. The UE, which receives Msg4 including a contention resolution identifier MAC CE, may consider the random access procedure as a success if it confirms that the contention resolution identifier MAC CE is the same as the one it transmitted. If the UE does not receive Msg4 including a contention resolution identifier that is the same as the contention resolution identifier it transmitted before the CR timer expires, the UE may consider the contention resolution as a failure.In the above two cases (i.e., when the UE already has a C-RNTI and when the UE does not have a C-RNTI), a UE that fails to resolve the contention returns to the random access resource selection process and retries the random access process and increments the RACH Tx counter value of the random access process (see PREAMBLE_TRANSMISSION_COUNTER described above).

[0167] However, if the cell where the UE performs the random access procedure is in operation with cell DTX / DRX set up, transmission / reception of specific DL / UL signals / channels that are pre-configured and / or defined (in the standard) may be turned OFF during the non-active period. For example, if a UE with an ongoing random access procedure transmits Msg3 and the cell enters the cell DTX non-active period while the BS must transmit PDCCH / PDSCH to the UE for contention resolution, the BS may not be able to transmit the PDCCH (scrambled with C-RNTI or TC-RNTI) or the PDSCH (scheduled by the PDCCH and carrying a MAC PDU with a contention resolution indicator MAC CE or CCCH SDU) until the CR timer expires, even though the BS successfully receives the Msg3 transmitted by the UE.

[0168] In such cases (e.g., when the cell DTX inactivity period starts while the UE transmits Msg3 and is waiting for the reception of the contention resolution related PDCCH and the corresponding PDSCH), the BS does not successfully receive Msg3, which causes the UE to fail the contention resolution. Taking this into account, in some implementations of this specification, the UE and the BS may operate as follows:

[0169] Referring to FIG. 10(a), in some implementations of the present specification, according to method (1-1), the BS and the UE may hold the CR timer during the cell DTX inactivity period and restart the CR timer when the cell DTX inactivity period ends. According to some implementations of the present specification, even if the cell DTX inactivity period starts while the CR timer is running, the CR timer is run for a set length, so that the length of time during which a contention resolution message may be transmitted can be guaranteed.

[0170] Alternatively, referring to FIG. 10(b), in some implementations of the present specification, according to method (1-2), the BS and the UE may not hold off on starting the CR timer even during the cell DTX inactive period, but instead may maintain the RACH TX counter value even if the timer expires. According to some implementations of the present specification, even if the BS successfully receives Msg3 transmitted by the UE but enters the cell DTX inactive period and thus cannot transmit a PDCCH / PDSCH to indicate successful contention resolution before the CR timer expires, the UE may reduce the probability of failure of the entire random access procedure by maintaining the preamble transmission counter without increasing it. Accordingly, an increase in the initial access delay may be prevented.

[0171] [Method #2] Signaling Method for Cell Barring of Rel-18 NES-Capable UEs and Rel-19 NES-Capable UEs

[0172] When a specific cell seeks to obtain energy saving benefits by turning OFF transmission / reception of pre-configured / defined DL / UL signals / channels with a specific active / inactive interval pattern, such as cell DTX / DRX configuration introduced in NR Release-18, legacy UEs that do not support cell DTX / DRX operation (e.g., only supporting features prior to Release-17) and UEs that support cell DTX / DRX operation may coexist within the cell. In this case, if the BS turns OFF CSI-RS transmission for CSI reporting in the pre-arranged cell DTX inactive interval, Rel-18 NES-capable UEs will not expect CSI-RS reception in the interval and will not perform CSI reporting, but legacy UEs that do not support the feature may calculate CSI and transmit unnecessary CSI reports even though no CSI-RS is transmitted. Therefore, the BS may not be able to take advantage of the energy saving opportunity through CSI-RS by continuing to transmit CSI-RS during the cell DTX inactive period, taking into account even legacy UEs.

[0173] Therefore, in some implementations of this specification, if a BS wishes to achieve energy savings through NES techniques introduced in a particular release, it may allow only NES-capable UEs supporting the feature to access the cell, and induce legacy UEs that do not support the feature to perform cell reselection by cell barring. This cell barring can be signaled by adding a specific bit to SIB1. For example, by introducing 2 bits in SIB1, and if the 2 bits are '00', the cell can be accessed only by Rel-18 NES-capable UEs, '01', '10', '1 ...

[0174] Here, Rel-18 NES-capable UE and Rel-19 NES-capable UE may refer to a UE supporting network energy saving techniques introduced in the Release-18 standard and a UE supporting network energy saving techniques introduced in the Release-19 standard, respectively. If the cell blocking indication field / bit(s) are not present in SIB1, the UE may determine whether to access a cell based on the legacy cell blocking indication.

[0175] According to Method #2, the BS can block a UE that does not support cell DTX / DRX from accessing a cell through specific field / bit(s) in SIB1 of a cell having cell DTX / DRX configuration. Based on the specific field / bit(s), a UE that supports cell DTX / DRX can perform a random access procedure to attempt to access the cell, and a UE that does not support cell DTX / DRX can perform cell search to find a cell to access without attempting a random access procedure for the cell. Therefore, according to Method #2, energy of the BS and the UE can be saved.

[0176] Method #1 and Method #2 described above can be applied alone or together. When Method #1 and Method #2 are applied together, for example, when a UE acquires SIB1 of a cell during a cell search process and is not blocked from accessing the cell based on cell blocking information of S1B1 of the cell according to Method #2, the UE can perform a random access process according to some implementations of the present specification of Method #1.

[0177] According to some implementations of this specification, energy of the BS and / or UE may be saved.

[0178] Figure 11 illustrates a UE operation flow according to some implementations of this specification.

[0179] A UE may perform operations according to some implementations of the present disclosure. The UE may include at least one transceiver; at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A processing device for the UE may include at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer-readable (non-volatile or non-transitory) storage medium may store at least one computer program comprising instructions that, when executed by at least one processor, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer program or computer program product may be recorded on at least one computer-readable (non-volatile or non-transitory) storage medium and may contain instructions that, when executed, cause (at least one processor) to perform operations according to some implementations of the present specification.

[0180] A method performed by the UE, or in the UE, the processing device, the computer-readable (non-volatile) storage medium, and / or the computer program product, the operations may include: setting a preamble transmission counter for a random access procedure to a first value; performing a first random access preamble transmission for the random access procedure on a cell (S1101); receiving a random access response to the first random access preamble transmission; transmitting an uplink channel based on the random access response; and starting a contention resolution timer based on transmitting the uplink channel (S1103). The method or operations may include: determining whether contention resolution is successful based on whether a downlink channel (e.g., a PDCCH and a corresponding PDSCH) indicating successful contention resolution is received before the contention resolution timer expires (S1105). The operations may include performing a second random access preamble transmission for the random access procedure based on the contention resolution timer expiring. The above method or operations may be: based on the fact that a cell DTX inactivity period for the cell starts while the contention resolution timer is running and the contention resolution timer has expired, the preamble transmission counter may be maintained at the first value (S1107a). The above method or operations may be: based on the fact that a downlink channel indicating successful contention resolution is received before the contention resolution timer has expired, the contention resolution may be considered successful, and the random access process may be considered successfully completed (S1107b).

[0181] In some implementations, the method or operations may include: monitoring a downlink channel for contention resolution based on the contention resolution timer being running and the cell being within a cell DTX active period.

[0182] In some implementations, the method or operations may include: not monitoring the downlink channel for contention resolution based on the cell being in the cell DTX inactive period.

[0183] In some implementations, the method or operations may include: incrementing the preamble transmission counter based on the cell DTX inactivity interval not starting while the contention resolution timer is running and the contention resolution timer has expired.

[0184] Figure 12 illustrates a BS operation flow according to some implementations of this specification.

[0185] A BS may perform operations according to some implementations of the present disclosure. The BS may include at least one transceiver; at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A processing device for the BS may include at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer-readable (non-volatile or non-transitory) storage medium may store at least one computer program comprising instructions that, when executed by the at least one processor, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer program or computer program product may be recorded on at least one computer-readable (non-volatile or non-transitory) storage medium and may contain instructions that, when executed, cause (at least one processor) to perform operations according to some implementations of the present specification.

[0186] A method performed by the BS, or in the BS, the processing device, the computer-readable (non-volatile) storage medium, and / or the computer program product, wherein the operations include: receiving a first random access preamble from a UE on a cell, the first random access preamble associated with a preamble transmission counter set to a first value for a random access procedure (S1201); transmitting a random access response to the first random access preamble to the UE (S1203); receiving an uplink channel based on the random access response (S1205); and attempting to transmit a signal indicating successful contention resolution (e.g., a PDCCH and a corresponding PDSCH) to the UE while a contention resolution timer started when the uplink channel is transmitted is running (S1207). The method or operations may further include: receiving a second random access preamble for the random access procedure when the contention resolution timer expires at the UE. While the contention resolution timer is running, the cell DTX inactivity period for the cell starts and the preamble transmission counter may be maintained at the first value based on the expiration of the contention resolution timer. Based on receiving a signal indicating successful contention resolution before the contention resolution timer expires, the UE may consider the contention resolution to be successful and may consider the random access procedure to be successfully completed.

[0187] In some implementations, the method or operations may include: transmitting a downlink channel for contention resolution on the cell based on the contention resolution timer being running and the cell being within a cell DTX active period.

[0188] In some implementations, the method or operations may include: not transmitting a downlink channel for contention resolution on the cell based on the cell being in the cell DTX inactive period.

[0189] In some implementations, the preamble transmission counter may be incremented based on the expiration of the contention resolution timer without the cell DTX inactivity period starting while the contention resolution timer is running.

[0190] As described above, the examples disclosed herein are provided to enable those skilled in the art to implement and practice the present disclosure. While the examples have been described above with reference to the examples of the present disclosure, those skilled in the art will appreciate that various modifications and variations may be made to the examples of the present disclosure. Accordingly, the present disclosure is not intended to be limited to the examples described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0191] Implementations of this specification can be used in wireless communication systems, BSs, UEs, and other equipment.

Claims

1. In a method using a user equipment (UE), Set the preamble transmission counter for the random access process to the first value; Performing a first random access preamble transmission for the above random access process on the cell; Receive a random access response to the first random access preamble transmission; Transmit the uplink channel based on the above random access response; Start the contention resolution timer based on the transmission of the above uplink channel; Including performing a second random access preamble transmission for the random access process based on the expiration of the contention resolution timer, While the contention resolution timer is running, a cell discontinuous transmission (DTX) inactivity period for the cell begins and the contention resolution timer expires, and the preamble transmission counter is maintained at the first value. method.

2. In paragraph 1, Comprising monitoring a downlink channel for contention resolution based on the contention resolution timer being running and the cell being within a cell DTX active period, method.

3. In paragraph 1, Including not monitoring the downlink channel for contention resolution based on the cell being in the cell DTX inactive period, method.

4. In paragraph 1, Incrementing the preamble transmission counter based on the expiration of the contention resolution timer without the cell DTX inactivity period starting while the contention resolution timer is running. method.

5. At least one processor; and At least one computer memory operably connectable to said at least one processor and storing instructions that, when executed, cause said at least one processor to perform operations for a user equipment (UE), said operations comprising: Set the preamble transmission counter for the random access process to the first value; Performing a first random access preamble transmission for the above random access process on the cell; Receive a random access response to the first random access preamble transmission; Transmit the uplink channel based on the above random access response; Start the contention resolution timer based on the transmission of the above uplink channel; Including performing a second random access preamble transmission for the random access process based on the expiration of the contention resolution timer, While the contention resolution timer is running, a cell discontinuous transmission (DTX) inactivity period for the cell begins and the contention resolution timer expires, and the preamble transmission counter is maintained at the first value. device.

6. In paragraph 5, the above actions are: Comprising monitoring a downlink channel for contention resolution based on the contention resolution timer being running and the cell being within a cell DTX active period, device.

7. In paragraph 5, the above actions are: Including not monitoring the downlink channel for contention resolution based on the cell being in the cell DTX inactive period, device.

8. In paragraph 5, the above actions are: Incrementing the preamble transmission counter based on the expiration of the contention resolution timer without the cell DTX inactivity period starting while the contention resolution timer is running. device.

9. In a computer-readable non-transitory storage medium, The storage medium stores at least one program code comprising instructions that, when executed, cause at least one processor to perform operations for a user equipment (UE), the operations comprising: Set the preamble transmission counter for the random access process to the first value; Performing a first random access preamble transmission for the above random access process on the cell; Receive a random access response to the first random access preamble transmission; Transmit the uplink channel based on the above random access response; Start the contention resolution timer based on the transmission of the above uplink channel; Including performing a second random access preamble transmission for the random access process based on the expiration of the contention resolution timer, While the contention resolution timer is running, a cell discontinuous transmission (DTX) inactivity period for the cell begins and the contention resolution timer expires, and the preamble transmission counter is maintained at the first value. Storage media.

10. In paragraph 9, the above actions are: Comprising monitoring a downlink channel for contention resolution based on the contention resolution timer being running and the cell being within a cell DTX active period, Storage media.

11. In paragraph 9, the above actions are: Including not monitoring the downlink channel for contention resolution based on the cell being in the cell DTX inactive period, Storage media.

12. In paragraph 9, the above actions are: Incrementing the preamble transmission counter based on the expiration of the contention resolution timer without the cell DTX inactivity period starting while the contention resolution timer is running. Storage media.

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