Patent Description:
Wireless communication systems are being widely deployed to provide various types of communication services such as voice and data. In general, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of the multiple access system include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, and a single carrier frequency division multiple access (SC-FDMA) system, and a multi carrier frequency division multiple access (MC-FDMA) system.

A wireless communication system uses various radio access technologies (RATs) such as long term evolution (LTE), LTE-advanced (LTE-A), and wireless fidelity (WiFi). 5th generation (<NUM>) is such a wireless communication system. Three key requirement areas of <NUM> include (<NUM>) enhanced mobile broadband (eMBB), (<NUM>) massive machine type communication (mMTC), and (<NUM>) ultra-reliable and low latency communications (URLLC). Some use cases may require multiple dimensions for optimization, while others may focus only on one key performance indicator (KPI). <NUM> supports such diverse use cases in a flexible and reliable way.

eMBB goes far beyond basic mobile Internet access and covers rich interactive work, media and entertainment applications in the cloud or augmented reality (AR). Data is one of the key drivers for <NUM> and in the <NUM> era, we may for the first time see no dedicated voice service. In <NUM>, voice is expected to be handled as an application program, simply using data connectivity provided by a communication system. The main drivers for an increased traffic volume are the increase in the size of content and the number of applications requiring high data rates. Streaming services (audio and video), interactive video, and mobile Internet connectivity will continue to be used more broadly as more devices connect to the Internet. Many of these applications require always-on connectivity to push real time information and notifications to users. Cloud storage and applications are rapidly increasing for mobile communication platforms. This is applicable for both work and entertainment. Cloud storage is one particular use case driving the growth of uplink data rates. <NUM> will also be used for remote work in the cloud which, when done with tactile interfaces, requires much lower end-to-end latencies in order to maintain a good user experience. Entertainment, for example, cloud gaming and video streaming, is another key driver for the increasing need for mobile broadband capacity. Entertainment will be very essential on smart phones and tablets everywhere, including high mobility environments such as trains, cars and airplanes. Another use case is augmented reality (AR) for entertainment and information search, which requires very low latencies and significant instant data volumes.

One of the most expected <NUM> use cases is the functionality of actively connecting embedded sensors in every field, that is, mMTC. It is expected that there will be <NUM> billion potential Internet of things (IoT) devices by <NUM>. In industrial IoT, <NUM> is one of areas that play key roles in enabling smart city, asset tracking, smart utility, agriculture, and security infrastructure.

URLLC includes services which will transform industries with ultra-reliable/available, low latency links such as remote control of critical infrastructure and self-driving vehicles. The level of reliability and latency are vital to smart-grid control, industrial automation, robotics, drone control and coordination, and so on.

Now, multiple use cases will be described in detail.

<NUM> may complement fiber-to-the home (FTTH) and cable-based broadband (or data-over-cable service interface specifications (DOCSIS)) as a means of providing streams at data rates of hundreds of megabits per second to giga bits per second. Such a high speed is required for TV broadcasts at or above a resolution of <NUM> (<NUM>, <NUM>, and higher) as well as virtual reality (VR) and AR. VR and AR applications mostly include immersive sport games. A special network configuration may be required for a specific application program. For VR games, for example, game companies may have to integrate a core server with an edge network server of a network operator in order to minimize latency.

The automotive sector is expected to be a very important new driver for <NUM>, with many use cases for mobile communications for vehicles. For example, entertainment for passengers requires simultaneous high capacity and high mobility mobile broadband, because future users will expect to continue their good quality connection independent of their location and speed. Other use cases for the automotive sector are AR dashboards. These display overlay information on top of what a driver is seeing through the front window, identifying objects in the dark and telling the driver about the distances and movements of the objects. In the future, wireless modules will enable communication between vehicles themselves, information exchange between vehicles and supporting infrastructure and between vehicles and other connected devices (e.g., those carried by pedestrians). Safety systems may guide drivers on alternative courses of action to allow them to drive more safely and lower the risks of accidents. The next stage will be remote-controlled or self-driving vehicles. These require very reliable, very fast communication between different self-driving vehicles and between vehicles and infrastructure. In the future, self-driving vehicles will execute all driving activities, while drivers are focusing on traffic abnormality elusive to the vehicles themselves. The technical requirements for self-driving vehicles call for ultra-low latencies and ultra-high reliability, increasing traffic safety to levels humans cannot achieve.

Smart cities and smart homes, often referred to as smart society, will be embedded with dense wireless sensor networks. Distributed networks of intelligent sensors will identify conditions for cost- and energy-efficient maintenance of the city or home. A similar setup can be done for each home, where temperature sensors, window and heating controllers, burglar alarms, and home appliances are all connected wirelessly. Many of these sensors are typically characterized by low data rate, low power, and low cost, but for example, real time high definition (HD) video may be required in some types of devices for surveillance.

The consumption and distribution of energy, including heat or gas, is becoming highly decentralized, creating the need for automated control of a very distributed sensor network. A smart grid interconnects such sensors, using digital information and communications technology to gather and act on information. This information may include information about the behaviors of suppliers and consumers, allowing the smart grid to improve the efficiency, reliability, economics and sustainability of the production and distribution of fuels such as electricity in an automated fashion. A smart grid may be seen as another sensor network with low delays.

The health sector has many applications that may benefit from mobile communications. Communications systems enable telemedicine, which provides clinical health care at a distance. It helps eliminate distance barriers and may improve access to medical services that would often not be consistently available in distant rural communities. It is also used to save lives in critical care and emergency situations. Wireless sensor networks based on mobile communication may provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

Wireless and mobile communications are becoming increasingly important for industrial applications. Wires are expensive to install and maintain, and the possibility of replacing cables with reconfigurable wireless links is a tempting opportunity for many industries. However, achieving this requires that the wireless connection works with a similar delay, reliability and capacity as cables and that its management is simplified. Low delays and very low error probabilities are new requirements that need to be addressed with <NUM>.

Finally, logistics and freight tracking are important use cases for mobile communications that enable the tracking of inventory and packages wherever they are by using location-based information systems. The logistics and freight tracking use cases typically require lower data rates but need wide coverage and reliable location information.

A wireless communication system is a multiple access system that supports communication of multiple users by sharing available system resources (a bandwidth, transmission power, etc.). Examples of multiple access systems include a CDMA system, an FDMA system, a TDMA system, an OFDMA system, an SC-FDMA system, and an MC-FDMA system.

Sidelink (SL) refers to a communication scheme in which a direct link is established between user equipments (UEs) and the UEs directly exchange voice or data without intervention of a base station (BS). SL is considered as a solution of relieving the BS of the constraint of rapidly growing data traffic.

Vehicle-to-everything (V2X) is a communication technology in which a vehicle exchanges information with another vehicle, a pedestrian, and infrastructure by wired/wireless communication. V2X may be categorized into four types: vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). V2X communication may be provided via a PC5 interface and/or a Uu interface.

As more and more communication devices demand larger communication capacities, there is a need for enhanced mobile broadband communication relative to existing RATs. Accordingly, a communication system is under discussion, for which services or UEs sensitive to reliability and latency are considered. The next-generation RAT in which eMBB, MTC, and URLLC are considered is referred to as new RAT or NR. In NR, V2X communication may also be supported.

<FIG> is a diagram illustrating V2X communication based on pre-NR RAT and V2X communication based on NR in comparison.

For V2X communication, a technique of providing safety service based on V2X messages such as basic safety message (BSM), cooperative awareness message (CAM), and decentralized environmental notification message (DENM) was mainly discussed in the pre-NR RAT. The V2X message may include location information, dynamic information, and attribute information. For example, a UE may transmit a CAM of a periodic message type and/or a DENM of an event-triggered type to another UE.

For example, the CAM may include basic vehicle information including dynamic state information such as a direction and a speed, vehicle static data such as dimensions, an external lighting state, path details, and so on. For example, the UE may broadcast the CAM which may have a latency less than <NUM>. For example, when an unexpected incident occurs, such as breakage or an accident of a vehicle, the UE may generate the DENM and transmit the DENM to another UE. For example, all vehicles within the transmission range of the UE may receive the CAM and/or the DENM. In this case, the DENM may have priority over the CAM.

In relation to V2X communication, various V2X scenarios are presented in NR. For example, the V2X scenarios include vehicle platooning, advanced driving, extended sensors, and remote driving.

For example, vehicles may be dynamically grouped and travel together based on vehicle platooning. For example, to perform platoon operations based on vehicle platooning, the vehicles of the group may receive periodic data from a leading vehicle. For example, the vehicles of the group may widen or narrow their gaps based on the periodic data.

For example, a vehicle may be semi-automated or full-automated based on advanced driving. For example, each vehicle may adjust a trajectory or maneuvering based on data obtained from a nearby vehicle and/or a nearby logical entity. For example, each vehicle may also share a dividing intention with nearby vehicles.

Based on extended sensors, for example, raw or processed data obtained through local sensor or live video data may be exchanged between vehicles, logical entities, terminals of pedestrians and/or V2X application servers. Accordingly, a vehicle may perceive an advanced environment relative to an environment perceivable by its sensor.

Based on remote driving, for example, a remote driver or a V2X application may operate or control a remote vehicle on behalf of a person incapable of driving or in a dangerous environment. For example, when a path may be predicted as in public transportation, cloud computing-based driving may be used in operating or controlling the remote vehicle. For example, access to a cloud-based back-end service platform may also be used for remote driving.

A scheme of specifying service requirements for various V2X scenarios including vehicle platooning, advanced driving, extended sensors, and remote driving is under discussion in NR-based V2X communication.

In 3GPP standardization related to SL communication as described above, a DRX configuration is under discussion. Specifically, alignment between an SL DRX configuration and a DRX configuration of a Uu interface is being discussed in relation to a DRX configuration method. In the case of SL unicast communication, discussion is focusing on a transmission UE. That is, a reception UE provides assistance information for determining a DRX configuration, and the transmission UE is intended to autonomously determines the DRX configuration or report the assistance information to a BS according to an operation mode.

Here, in consideration of a characteristic of a relay UE in a state in which a remote UE having difficulty in direct connection with the BS is connected to the BS through the relay UE, it is necessary to more precisely control the relationship between DRX of the Uu interface and SL DRX. <CIT>, <CIT> and <CIT> form the related prior art.

In various embodiments of the present disclosure, "/" and "," should be interpreted as "and/or". Further, "A, B" may mean "A and/or B". Further, "A/B/C" may mean "at least one of A, B and/or C". Further, "A, B, C" may mean "at least one of A, B and/or C".

In various embodiments of the present disclosure, "or" should be interpreted as "and/or". For example, "A or B" may include "only A", "only B", and/or "both A and B". In other words, "or" should be interpreted as "additionally or alternatively".

Techniques described herein may be used in various wireless access systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier-frequency division multiple access (SC-FDMA), and so on. CDMA may be implemented as a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented as a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented as a radio technology such as IEEE <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, evolved-UTRA (E-UTRA), or the like. IEEE <NUM> is an evolution of IEEE <NUM>. 16e, offering backward compatibility with an IRRR <NUM>. 16e-based system. UTRA is a part of universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using evolved UTRA (E-UTRA). 3GPP LTE employs OFDMA for downlink (DL) and SC-FDMA for uplink (UL). LTE-advanced (LTE-A) is an evolution of 3GPP LTE.

A successor to LTE-A, 5th generation (<NUM>) new radio access technology (NR) is a new clean-state mobile communication system characterized by high performance, low latency, and high availability. <NUM> NR may use all available spectral resources including a low frequency band below <NUM>, an intermediate frequency band between <NUM> and <NUM>, and a high frequency (millimeter) band of <NUM> or above.

While the following description is given mainly in the context of LTE-A or <NUM> NR for the clarity of description, the technical idea of an embodiment of the present disclosure is not limited thereto.

<FIG> illustrates the structure of an NR system according to an embodiment of the present disclosure.

Referring to <FIG>, a next generation radio access network (NG-RAN) may include a next generation Node B (gNB) and/or an eNB, which provides user-plane and control-plane protocol termination to a UE.

In <FIG>, the NG-RAN is shown as including only gNBs, by way of example. A gNB and an eNB are connected to each other via an Xn interface. The gNB and the eNB are connected to a <NUM> core network (5GC) via an NG interface. More specifically, the gNB and the eNB are connected to an access and mobility management function (AMF) via an NG-C interface and to a user plane function (UPF) via an NG-U interface.

<FIG> illustrates functional split between the NG-RAN and the 5GC according to an embodiment of the present disclosure.

Referring to <FIG>, a gNB may provide functions including inter-cell radio resource management (RRM), radio admission control, measurement configuration and provision, and dynamic resource allocation. The AMF may provide functions such as non-access stratum (NAS) security and idle-state mobility processing. The UPF may provide functions including mobility anchoring and protocol data unit (PDU) processing. A session management function (SMF) may provide functions including UE Internet protocol (IP) address allocation and PDU session control.

Based on the lowest three layers of the open system interconnection (OSI) reference model known in communication systems, the radio protocol stack between a UE and a network may be divided into Layer <NUM> (L1), Layer <NUM> (L2) and Layer <NUM> (L3). These layers are defined in pairs between a UE and an Evolved UTRAN (E-UTRAN), for data transmission via the Uu interface. The physical (PHY) layer at L1 provides an information transfer service on physical channels. The radio resource control (RRC) layer at L3 functions to control radio resources between the UE and the network. For this purpose, the RRC layer exchanges RRC messages between the UE and an eNB.

<FIG> illustrates a radio protocol architecture according to an embodiment of the present disclosure.

Specifically, <FIG> illustrates a radio protocal architecture for a user plane, and <FIG> illustrates a radio protocal architecture for a control plane. The user plane is a protocol stack for user data transmission, and the control plane is a protocl stack for control signal transmission.

Referring to <FIG>, the PHY layer provides an information transfer service to its higher layer on physical channels. The PHY layer is connected to the medium access control (MAC) layer through transport channels and data is transferred between the MAC layer and the PHY layer on the transport channels. The transport channels are divided according to features with which data is transmitted via a radio interface.

Data is transmitted on physical channels between different PHY layers, that is, the PHY layers of a transmitter and a receiver. The physical channels may be modulated in orthogonal frequency division multiplexing (OFDM) and use time and frequencies as radio resources.

The MAC layer provides services to a higher layer, radio link control (RLC) on logical channels. The MAC layer provides a function of mapping from a plurality of logical channels to a plurality of transport channels. Further, the MAC layer provides a logical channel multiplexing function by mapping a plurality of logical channels to a single transport channel. A MAC sublayer provides a data transmission service on the logical channels.

The RLC layer performs concatenation, segmentation, and reassembly for RLC serving data units (SDUs). In order to guarantee various quality of service (QoS) requirements of each radio bearer (RB), the RLC layer provides three operation modes, transparent mode (TM), unacknowledged mode (UM), and acknowledged Mode (AM). An AM RLC provides error correction through automatic repeat request (ARQ).

The RRC layer is defined only in the control plane and controls logical channels, transport channels, and physical channels in relation to configuration, reconfiguration, and release of RBs. An RB refers to a logical path provided by L1 (the PHY layer) and L2 (the MAC layer, the RLC layer, and the packet data convergence protocol (PDCP) layer), for data transmission between the UE and the network.

The user-plane functions of the PDCP layer include user data transmission, header compression, and ciphering. The control-plane functions of the PDCP layer include control-plane data transmission and ciphering/integrity protection.

RB establishment amounts to a process of defining radio protocol layers and channel features and configuring specific parameters and operation methods in order to provide a specific service. RBs may be classified into two types, signaling radio bearer (SRB) and data radio bearer (DRB). The SRB is used as a path in which an RRC message is transmitted on the control plane, whereas the DRB is used as a path in which user data is transmitted on the user plane.

Once an RRC connection is established between the RRC layer of the UE and the RRC layer of the E-UTRAN, the UE is placed in RRC_CONNECTED state, and otherwise, the UE is placed in RRC_IDLE state. In NR, RRC _INACTIVE state is additionally defined. A UE in the RRC _INACTIVE state may maintain a connection to a core network, while releasing a connection from an eNB.

DL transport channels carrying data from the network to the UE include a broadcast channel (BCH) on which system information is transmitted and a DL shared channel (DL SCH) on which user traffic or a control message is transmitted. Traffic or a control message of a DL multicast or broadcast service may be transmitted on the DL-SCH or a DL multicast channel (DL MCH). UL transport channels carrying data from the UE to the network include a random access channel (RACH) on which an initial control message is transmitted and an UL shared channel (UL SCH) on which user traffic or a control message is transmitted.

The logical channels which are above and mapped to the transport channels include a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and a multicast traffic channel (MTCH).

A physical channel includes a plurality of OFDM symbol in the time domain by a plurality of subcarriers in the frequency domain. One subframe includes a plurality of OFDM symbols in the time domain. An RB is a resource allocation unit defined by a plurality of OFDM symbols by a plurality of subcarriers. Further, each subframe may use specific subcarriers of specific OFDM symbols (e.g., the first OFDM symbol) in a corresponding subframe for a physical DL control channel (PDCCH), that is, an L1/L2 control channel. A transmission time interval (TTI) is a unit time for subframe transmission.

Now, a description will be given of sidelink (SL) communication.

<FIG> illustrates a radio protocol architecture for SL communication according to an embodiment of the present disclosure. Specifically, <FIG> illustrates a user-plane protocol stack in LTE, and <FIG> illustrates a control-plane protocol stack in LTE.

Hereinafter, a sidelink synchronization signal (SLSS) and synchronization information will be described.

The SLSS is an SL-specific sequence, and may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS). The PSSS may be referred to as a sidelink primary synchronization signal (S-PSS), and the SSSS may be referred to as a sidelink secondary synchronization signal (S-SSS). For example, length-<NUM>-sequences may be used for the S-PSS, and length-<NUM> gold sequences may be used for the S-SSS. For example, the UE may detect an initial signal and acquire synchronization using the S-PSS. For example, the UE may acquire detailed synchronization using the S-PSS and the S-SSS, and may detect a synchronization signal ID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast) channel on which basic (system) information that the UE needs to know first before transmission and reception of an SL signal is transmitted. For example, the basic information may include SLSS related information, a duplex mode (DM), time division duplex uplink/downlink (TDD UL/DL) configuration, resource pool related information, the type of an application related to the SLSS, a subframe offset, and broadcast information. For example, for evaluation of PSBCH performance, the payload size of PSBCH in NR V2X may be <NUM> bits including CRC of <NUM> bits.

The S-PSS, S-SSS, and PSBCH may be included in a block format (e.g., an SL synchronization signal (SS)/PSBCH block, hereinafter sidelink-synchronization signal block (S-SSB)) supporting periodic transmission. The S-SSB may have the same numerology (i.e., SCS and CP length) as a physical sidelink control channel (PSCCH)/physical sidelink shared channel (PSSCH) in the carrier, and the transmission bandwidth thereof may be within a (pre)set sidelink BWP (SL BWP). For example, the bandwidth of the S-SSB may be <NUM> resource blocks (RBs). For example, the PSBCH may span <NUM> RBs. The frequency position of the S-SSB may be (pre)set. Accordingly, the UE does not need to perform hypothesis detection at a frequency to discover the S-SSB in the carrier.

Hereinafter, synchronization acquisition by an SL UE will be described.

In TDMA and FDMA systems, accurate time and frequency synchronization is essential. Inaccurate time and frequency synchronization may lead to degradation of system performance due to inter-symbol interference (ISI) and inter-carrier interference (ICI). The same is true for V2X. For time/frequency synchronization in V2X, a sidelink synchronization signal (SLSS) may be used in the PHY layer, and master information block-sidelink-V2X (MIB-SL-V2X) may be used in the RLC layer.

<FIG> illustrates a synchronization source or a synchronization reference of V2X according to an embodiment of the present disclosure.

Referring to <FIG>, in V2X, a UE may be directly synchronized with a global navigation satellite system (GNSS) or may be indirectly synchronized with the GNSS through a UE (in network coverage or out of network coverage) that is directly synchronized with the GNSS. If the GNSS is configured as a synchronization source, a UE may calculate a direct frame number (DFN) and a subframe number using coordinated universal time (UTC) and a (pre)configured DFN offset.

Alternatively, a UE may be directly synchronized with a BS or may be synchronized with another UE that is synchronized in time/frequency with the BS. For example, the BS may be an eNB or a gNB. For example, when a UE is in network coverage, the UE may receive synchronization information provided by the BS and may be directly synchronized with the BS. Next, the UE may provide the synchronization information to another adjacent UE. If a timing of the BS is configured as a synchronization reference, the UE may follow a cell associated with a corresponding frequency (when the UE is in cell coverage in frequency) or a primary cell or a serving cell (when the UE is out of cell coverage in frequency), for synchronization and DL measurement.

The BS (e.g., serving cell) may provide a synchronization configuration for a carrier used for V2X/SL communication. In this case, the UE may conform to the synchronization configuration received from the BS. If the UE fails to detect any cell in the carrier used for V2X/SL communication and fails to receive the synchronization configuration from the serving cell, the UE may conform to a preset synchronization configuration.

Alternatively, the UE may be synchronized with another UE that has failed to directly or indirectly acquire the synchronization information from the BS or the GNSS. A synchronization source and a preference may be preconfigured for the UE. Alternatively, the synchronization source and the preference may be configured through a control message provided by the BS.

An SL synchronization source may be associated with a synchronization priority level. For example, the relationship between synchronization sources and synchronization priority levels may be defined as shown in Table <NUM> or Table <NUM>. Table <NUM> or Table <NUM> are purely exemplary and the relationship between the synchronization sources and the synchronization priority levels may be defined in various manners.

In Table <NUM> or Table <NUM>, P0 may represent the highest priority, and P6 may represent the lowest priority. In Table <NUM> or Table <NUM>, the BS may include at least one of a gNB or an eNB.

Whether to use GNSS-based synchronization or eNB/gNB-based synchronization may be (pre)configured. In a single-carrier operation, the UE may derive a transmission timing thereof from an available synchronization reference having the highest priority.

For example, the UE may (re)select a synchronization reference and obtain synchronization from the synchronization reference. Based on the obtained synchronization, the UE may perform SL communication (e.g., PSCCH/PSSCH transmission/reception, physical sidelink feedback channel (PSFCH) transmission/reception, S-SSB transmission/reception, reference signal transmission/reception, etc.).

<FIG> and <FIG> are diagrams illustrating an SL DRX configuration method in 3GPP standardization constituting the premise of the present disclosure.

As illustrated in <FIG>, SL may be configured through PC5 RRC connection between a transmission (Tx) UE and a reception (Rx) UE. In <FIG>, when a first UE <NUM> operates as the Tx UE, a second UE <NUM> operates as the Rx UE and, when the first UE <NUM> operates as the Rx UE, the second UE <NUM> operates as the Tx UE.

In either case, the second UE <NUM> may be referred to as a peer UE from the viewpoint of the first UE <NUM>.

The DRX configuration method will now be described under the assumption that the first UE <NUM> operates as the Tx UE. Alignment between a Uu DRX configuration and an SL DRX configuration may be based on a UE in an RRC connection state among the Tx UE and Rx UE. As illustrated in <FIG>, the first UE <NUM> operating as the Tx UE may receive assistance information (e.g., UEAssistanceInformationSL of 3GPP) for determining the SL DRX configuration from the second UE <NUM>, which is a peer UE operating as the Rx UE. The assistance information is for the SL DRX configuration during unicast communication between UEs and may be considered as information about a preferred SL DRX configuration from the viewpoint of the Rx UE.

<FIG> illustrates an operation method of the first UE <NUM> upon receiving such assistance information according to the invention.

Upon receiving the assistance information as described above (S810), the first UE performs a different operation depending on whether the first UE operates in an RRC_Connected state (S820). When the first UE operates not in the RRC_Connected state and but in an RRC_IDLE or RRC _INACTIVE state, the first UE autonomously determines the SL DRX configuration based on the assistance information of the second UE (S850).

If the first UE operates in the RRC_Connected state, the operation of the first UE <NUM> is differently determined according to an SL resource allocation mode (S830). The SL resource allocation mode is divided into mode <NUM> and mode <NUM>. In mode <NUM>, a gNB operates by allocating resources to UEs within coverage and, in mode <NUM>, UEs operate by autonomously determining resources.

When the first UE operates in mode <NUM>, the first UE may report the assistance information of the second UE to the gNB (S840). The gNB may provide SL DRX for the second UE and, if necessary, Uu/SL DRX configuration information for the first UE, based on the reported assistance information.

When the first UE operates in mode <NUM>, the first UE may autonomously determine the SL DRX configuration of the second UE based on the assistance information of the second UE, instead of providing the received assistance information of the second UE to the gNB, and provide the SL DRX configuration of the second UE to the second UE.

However, more delicate alignment may be needed between Uu DRX and SL DRX when a UE operates as a relay UE that relays connection between a remote UE and a gNB, unlike the case of regulating the operation method according to the above-described embodiment with reference to <FIG> and <FIG>. This is because, if a DRX configuration of an on-duration between Uu DRX and SL DRX is severely misaligned, it may be difficult to satisfy QoS of data transmitted to the remote UE.

<FIG> is a diagram illustrating an operating method of a U2N relay UE for an SL DRX configuration according to the invention.

A UE-to-network (U2N) relay means that a U2N relay UE performs a relay operation between a remote UE and a gNB in an environment in which it is difficult for the remote UE to be directly connected to the gNB. In an upper portion of <FIG>, the remote UE, the relay UE, and the gNB are sequentially indicated.

When the remote UE operates as an Rx UE, the remote UE transmits in the claimed invention above-described assistance information to the relay UE (S910). Thus, the relay UE that has received the assistance information is regarded as operating as a Tx UE as described above with reference to <FIG>.

In the claimed invention, the relay UE reports the assistance information received from the remote UE to the gNB regardless of a resource allocation mode thereof (S920). That is, even when the relay UE operates in mode <NUM>, the relay UE transmits the SL assistance information received from the remote UE to the gNB. The SL assistance information may be, for example, sidelink UE information (SUI) or UE assistance information (UAI) of 3GPP. As will be described later, the above information may be transmitted by being combined with various procedures using a characteristic of being reported to the gNB regardless of the operation mode of the relay UE.

When the relay UE receives the assistance information received from the remote UE, the gNB configures the SL DRX configuration for the remote UE with respect to the relay UE (S930). That is, the relay UE may not configure SL DRX for the remote UE even when operating in mode <NUM>.

Specifically, the gNB configures in the claimed invention Uu DRX for the relay UE for a DL operation and indicates an SL DRX configuration value for the remote UE (S930). In addition, the gNB may configure, for the remote UE, the SL DRX value transparent to the relay UE. That is, the gNB may configure the SL DRX configuration for each of the relay UE and the remote UE.

As another example, the gNB may configure, only for the relay UE, Uu DRX and SL DRX for the remote UE. Upon receiving Uu DRX and SL DRX, the relay UE may transmit the SL DRX value to the remote UE (S940).

<FIG> illustrates the method according to the embodiment described with reference to <FIG>, which is applied to the operation method of <FIG>.

The operations of steps S810, S820, S840, and S850 illustrated in <FIG> may operate in the same manner as in <FIG>. However, in the embodiment of <FIG>, since the UE that receives assistance information from a peer UE reports the assistance information to the gNB regardless of a resource allocation mode, it is intended that step S830 of <FIG> for determining the resource allocation mode be improved.

That is, when the UE that has received the assistance information from the peer UE is in an RRC_Connected state, the UE may determine whether the UE is operating in mode <NUM> or operating as a relay UE (S1000). If the UE operates as the relay UE, the UE reports the received assistance information of the peer UE to the gNB even if the UE is operating in mode <NUM> as described above (S840) according to the proposed method.

<FIG> is a diagram illustrating a method of performing an RRC configuration according to the embodiment described above with reference to <FIG>.

Unlike the case in which the U2N relay UE serving as the Tx UE differently determines, according to a mode thereof, whether to report the received assistance information to the gNB or to autonomously determine the DRX configuration, if it is regulated that the U2N relay UE report the configuration to the gNB regardless of mode thereof, there is an additional advantage of using the assistance information received from the remote UE in combination with various procedures.

<FIG> illustrates a process of performing an RRC configuration in a U2N relay situation.

In step <NUM>, a U2N remote UE and a U2N relay UE may perform a discovery procedure and establish PC5 RRC connection based on the discovery procedure.

In step <NUM>, the remote UE may transmit an RRC setup request message (referred to as RRCReestablishmentRequest or RRCResumeRequest) to a gNB through the relay UE which is PC5-RRC-connected to the remote UE. This embodiment proposes transmitting the RRC setup request message including the assistance information for determining the above-described SL DRX configuration.

In step <NUM>, PC5 and Uu RLC channels for SRB1 may be prepared.

In step <NUM>, the gNB may transmit an RRC Setup Complete message to the remote UE through the relay UE based on the information received in step <NUM>. In this case, the gNB may configure SL DRX with reference to the assistance information received from the remote UE. In this case, the SL DRX configuration information may be transmitted by being included in an RRCSetup (referred to as RRCReestablishment or RRCResume) message for the remote UE.

In addition, the remote UE may inform even the relay UE of the SL DRX configuration allocated to the remote UE through an RRCReconfiguration message. This serves to cause the relay UE to transmit a message received from the gNB in alignment with an active time of the remote UE. That is, in a UL operation, SL DRX of the remote UE may be configured by the gNB. SL DRX may be included in a message for existing RRC connection establishment or may be configured through a separate RRC message.

Next, in step <NUM>, a configuration related to a security mode may be performed, and in step <NUM>, an RRC reconfiguration procedure for SRB2/DRB may be performed in a U2N relay situation.

On the other hand, another embodiment of the present disclosure proposes that an SL DRX configuration for the relay UE or an SL DRX configuration to be used by the remote UE after the remote UE is connected to the relay UE be included in an RRCReconfiguration message indicating path switching (/handover (HO)) transmitted to the remote UE during direct-to-indirect path switching (/HO).

The relay UE prepared for path switching (/HO) with the remote UE may receive an SL DRX configuration for the remote UE and an SL DRX configuration to be used by the relay UE from a serving gNB thereof.

Referring to <FIG>, a communication system <NUM> applied to the present disclosure includes wireless devices, BSs, and a network. Herein, the wireless devices represent devices performing communication using RAT (e.g., <NUM> NR or LTE) and may be referred to as communication/radio/SG devices. The wireless devices may include, without being limited to, a robot 100a, vehicles 100b-<NUM> and 100b-<NUM>, an extended reality (XR) device 100c, a hand-held device 100d, a home appliance 100e, an Internet of things (IoT) device 100f, and an artificial intelligence (AI) device/server <NUM>. Herein, the vehicles may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an augmented reality (AR)/virtual reality (VR)/mixed reality (MR) device and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook). For example, the BSs and the network may be implemented as wireless devices and a specific wireless device 200a may operate as a BS/network node with respect to other wireless devices.

For example, the vehicles 100b-<NUM> and 100b-<NUM> may perform direct communication (e.g. V2V/V2X communication).

Wireless communication/connections 150a, 150b, or 150c may be established between the wireless devices 100a to 100f/BS <NUM>, or BS <NUM>/BS <NUM>. Herein, the wireless communication/connections may be established through various RATs (e.g., <NUM> NR) such as UL/DL communication 150a, sidelink communication 150b (or, D2D communication), or inter BS communication (e.g. relay, integrated access backhaul (IAB)). The wireless devices and the BSs/the wireless devices may transmit/receive radio signals to/from each other through the wireless communication/connections 150a and 150b. For example, the wireless communication/connections 150a and 150b may transmit/receive signals through various physical channels. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/demapping), and resource allocating processes, for transmitting/receiving radio signals, may be performed based on the various proposals of the present disclosure.

Herein, {the first wireless device <NUM> and the second wireless device <NUM>} may correspond to {the wireless device 100x and the BS <NUM>} and/or {the wireless device 100x and the wireless device 100x}.

The one or more processors <NUM> and <NUM> may generate one or more Protocol Data Units (PDUs) and/or one or more service data unit (SDUs) according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document.

As an 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 the one or more processors <NUM> and <NUM>.

<FIG> illustrates a vehicle or an autonomous driving vehicle applied to the present disclosure. The vehicle or autonomous driving vehicle may be implemented by a mobile robot, a car, a train, a manned/unmanned aerial vehicle (AV), a ship, etc..

Referring to <FIG>, a vehicle or autonomous driving vehicle <NUM> may include an antenna unit <NUM>, a communication unit <NUM>, a control unit <NUM>, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The blocks <NUM>/<NUM>/140a to 140d correspond to the blocks <NUM>/<NUM>/<NUM> of FIG. <NUM>, respectively.

The control unit <NUM> may perform various operations by controlling elements of the vehicle or the autonomous driving vehicle <NUM>. The control unit <NUM> may include an ECU. The driving unit 140a may cause the vehicle or the autonomous driving vehicle <NUM> to drive on a road. The driving unit 140a may include an engine, a motor, a powertrain, a wheel, a brake, a steering device, etc. The power supply unit 140b may supply power to the vehicle or the autonomous driving vehicle <NUM> and include a wired/wireless charging circuit, a battery, etc. The sensor unit 140c may acquire a vehicle state, ambient environment information, user information, etc. The sensor unit 140c may include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a position module, a vehicle forward/backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illumination sensor, a pedal position sensor, etc. The autonomous driving unit 140d may implement technology for maintaining a lane on which a vehicle is driving, technology for automatically adjusting speed, such as adaptive cruise control, technology for autonomously driving along a determined path, technology for driving by automatically setting a path if a destination is set, and the like.

For example, the communication unit <NUM> may receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d may generate an autonomous driving path and a driving plan from the obtained data. The control unit <NUM> may control the driving unit 140a such that the vehicle or the autonomous driving vehicle <NUM> may move along the autonomous driving path according to the driving plan (e.g., speed/direction control). In the middle of autonomous driving, the communication unit <NUM> may aperiodically/periodically acquire recent traffic information data from the external server and acquire surrounding traffic information data from neighboring vehicles. In the middle of autonomous driving, the sensor unit 140c may obtain a vehicle state and/or surrounding environment information. The autonomous driving unit 140d may update the autonomous driving path and the driving plan based on the newly obtained data/information. The communication unit <NUM> may transfer information about a vehicle position, the autonomous driving path, and/or the driving plan to the external server. The external server may predict traffic information data using AI technology, etc., based on the information collected from vehicles or autonomous driving vehicles and provide the predicted traffic information data to the vehicles or the autonomous driving vehicles.

<FIG> illustrates a vehicle applied to the present disclosure. The vehicle may be implemented as a transport means, an aerial vehicle, a ship, etc..

Referring to <FIG>, a vehicle <NUM> may include a communication unit <NUM>, a control unit <NUM>, a memory unit <NUM>, an I/O unit 140a, and a positioning unit 140b. Herein, the blocks <NUM> to <NUM>/140a and 140b correspond to blocks <NUM> to <NUM>/<NUM>.

The communication unit <NUM> may transmit and receive signals (e.g., data and control signals) to and from external devices such as other vehicles or BSs. The control unit <NUM> may perform various operations by controlling constituent elements of the vehicle <NUM>. The memory unit <NUM> may store data/parameters/programs/code/commands for supporting various functions of the vehicle <NUM>. The I/O unit 140a may output an AR/VR object based on information within the memory unit <NUM>. The I/O unit 140a may include an HUD. The positioning unit 140b may acquire information about the position of the vehicle <NUM>. The position information may include information about an absolute position of the vehicle <NUM>, information about the position of the vehicle <NUM> within a traveling lane, acceleration information, and information about the position of the vehicle <NUM> from a neighboring vehicle. The positioning unit 140b may include a GPS and various sensors.

As an example, the communication unit <NUM> of the vehicle <NUM> may receive map information and traffic information from an external server and store the received information in the memory unit <NUM>. The positioning unit 140b may obtain the vehicle position information through the GPS and various sensors and store the obtained information in the memory unit <NUM>. The control unit <NUM> may generate a virtual object based on the map information, traffic information, and vehicle position information and the I/O unit 140a may display the generated virtual object in a window in the vehicle (<NUM> and <NUM>). The control unit <NUM> may determine whether the vehicle <NUM> normally drives within a traveling lane, based on the vehicle position information. If the vehicle <NUM> abnormally exits from the traveling lane, the control unit <NUM> may display a warning on the window in the vehicle through the I/O unit 140a. In addition, the control unit <NUM> may broadcast a warning message regarding driving abnormity to neighboring vehicles through the communication unit <NUM>. According to situation, the control unit <NUM> may transmit the vehicle position information and the information about driving/vehicle abnormality to related organizations.

<FIG> illustrates a robot applied to the present disclosure. The robot may be categorized into an industrial robot, a medical robot, a household robot, a military robot, etc., according to a used purpose or field.

Referring to <FIG>, a robot <NUM> may include a communication unit <NUM>, a control unit <NUM>, a memory unit <NUM>, an I/O unit 140a, a sensor unit 140b, and a driving unit 140c. Herein, the blocks <NUM> to <NUM>/140a to 140c correspond to the blocks <NUM> to <NUM>/<NUM> of <FIG>, respectively.

The communication unit <NUM> may transmit and receive signals (e.g., driving information and control signals) to and from external devices such as other wireless devices, other robots, or control servers. The control unit <NUM> may perform various operations by controlling constituent elements of the robot <NUM>. The memory unit <NUM> may store data/parameters/programs/code/commands for supporting various functions of the robot <NUM>. The I/O unit 140a may obtain information from the exterior of the robot <NUM> and output information to the exterior of the robot <NUM>. The I/O unit 140a may include a camera, a microphone, a user input unit, a display unit, a speaker, and/or a haptic module. The sensor unit 140b may obtain internal information of the robot <NUM>, surrounding environment information, user information, etc. The sensor unit 140b may include a proximity sensor, an illumination sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, a radar, etc. The driving unit 140c may perform various physical operations such as movement of robot joints. In addition, the driving unit 140c may cause the robot <NUM> to travel on the road or to fly. The driving unit 140c may include an actuator, a motor, a wheel, a brake, a propeller, etc..

<FIG> illustrates an AI device applied to the present disclosure. The AI device may be implemented by a fixed device or a mobile device, such as a TV, a projector, a smartphone, a PC, a notebook, a digital broadcast terminal, a tablet PC, a wearable device, a Set Top Box (STB), a radio, a washing machine, a refrigerator, a digital signage, a robot, a vehicle, etc..

Referring to <FIG>, an AI device <NUM> may include a communication unit <NUM>, a control unit <NUM>, a memory unit <NUM>, an I/O unit 140a/140b, a learning processor unit 140c, and a sensor unit 140d. The blocks <NUM> to <NUM>/140a to 140d correspond to blocks <NUM> to <NUM>/<NUM>, respectively.

The communication unit <NUM> may transmit and receive wired/radio signals (e.g., sensor information, user input, learning models, or control signals) to and from external devices such as other AI devices (e.g., 100x, <NUM>, or <NUM> of <FIG>) or an AI server (e.g., <NUM> of <FIG>) using wired/wireless communication technology. To this end, the communication unit <NUM> may transmit information within the memory unit <NUM> to an external device and transmit a signal received from the external device to the memory unit <NUM>.

The control unit <NUM> may determine at least one feasible operation of the AI device <NUM>, based on information which is determined or generated using a data analysis algorithm or a machine learning algorithm. The control unit <NUM> may perform an operation determined by controlling constituent elements of the AI device <NUM>. For example, the control unit <NUM> may request, search, receive, or use data of the learning processor unit 140c or the memory unit <NUM> and control the constituent elements of the AI device <NUM> to perform a predicted operation or an operation determined to be preferred among at least one feasible operation. The control unit <NUM> may collect history information including the operation contents of the AI device <NUM> and operation feedback by a user and store the collected information in the memory unit <NUM> or the learning processor unit 140c or transmit the collected information to an external device such as an AI server (<NUM> of <FIG>). The collected history information may be used to update a learning model.

The memory unit <NUM> may store data for supporting various functions of the AI device <NUM>. For example, the memory unit <NUM> may store data obtained from the input unit 140a, data obtained from the communication unit <NUM>, output data of the learning processor unit 140c, and data obtained from the sensor unit <NUM>. The memory unit <NUM> may store control information and/or software code needed to operate/drive the control unit <NUM>.

The input unit 140a may acquire various types of data from the exterior of the AI device <NUM>. For example, the input unit 140a may acquire learning data for model learning, and input data to which the learning model is to be applied. The input unit 140a may include a camera, a microphone, and/or a user input unit. The output unit 140b may generate output related to a visual, auditory, or tactile sense. The output unit 140b may include a display unit, a speaker, and/or a haptic module. The sensing unit <NUM> may obtain at least one of internal information of the AI device <NUM>, surrounding environment information of the AI device <NUM>, and user information, using various sensors. The sensor unit <NUM> may include a proximity sensor, an illumination sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, and/or a radar.

The learning processor unit 140c may learn a model consisting of artificial neural networks, using learning data. The learning processor unit 140c may perform AI processing together with the learning processor unit of the AI server (<NUM> of <FIG>). The learning processor unit 140c may process information received from an external device through the communication unit <NUM> and/or information stored in the memory unit <NUM>. In addition, an output value of the learning processor unit 140c may be transmitted to the external device through the communication unit <NUM> and may be stored in the memory unit <NUM>.

Claim 1:
A method of relaying, by a first user equipment, UE, (100a-f; <NUM>) sidelink communication (150b) between a base station, BS, (<NUM>) and a second UE (100a-f; <NUM>) in a wireless communication system, the method comprising:
receiving (S910) assistance information for determining a sidelink discontinuous reception, DRX, configuration from the second UE (100a-f; <NUM>);
transmitting (S920) the assistance information to the BS (<NUM>) regardless of a resource allocation mode of the first UE (100a-f; <NUM>);
receiving (S930) Uu link DRX configuration information and sidelink DRX configuration information from the BS (<NUM>); and
transmitting (S940) the sidelink DRX configuration information to the second UE (100a-f; <NUM>).