Method and apparatus for sharing ta information through sidelink

Abstract

The present document relates to a method and apparatus for sharing timing advance (TA) information through a sidelink. To this end, a method by which a second user equipment (UE) communicates with a network comprises: a first user equipment receiving, from the second user equipment through a sidelink, TA information obtained by performing a random access procedure on the network; and the second user equipment performing communication with the network by using the TA information, wherein the receiving of the TA information through the sidelink is performed when the network satisfies at least one of predetermined conditions including a first condition including a non-terrestrial network (NTN).

Description

Method for sharing TA information through sidelink and device therefor

[0001] The following description relates to a method for performing communication by sharing TA (Timing Advance) information through sidelink and a device therefor.

[0002] Wireless communication systems utilize a variety of technologies, including LTE, LTE-Advanced, and WiFi, and 5G is also included. The three main usage scenarios for 5G include (1) Enhanced Mobile Broadband (eMBB), (2) Massive Machine Type Communication (mMTC), and (3) Ultra-reliable and Low Latency Communications (URLLC). Some use cases may require optimization across multiple areas, while others may focus on just a single Key Performance Indicator (KPI). 5G supports these diverse use cases in a flexible and reliable manner.

[0003] Meanwhile, standardization of NTN (Non-Terrestrial Network) is in full swing starting with Release 17 during the 5G standardization process.

[0004] Figure 1 is a drawing to explain the concept of NTN.

[0005] Specifically, FIG. 1 is a drawing citing the concept of various types of NTN introduced in “5G from Space: An Overview of 3GPP Non-Terrestrial Networks” (authors, Xingqin Lin et al.), and NTN may include a satellite network (110), a high-latitude platform station (120) as an IMT base station, an air-ground network (130), etc.

[0006] These various types of networks can provide efficient communication services to remote areas (140) by utilizing wide coverage as conceptualized and illustrated in Fig. 1, and have the advantage of being able to provide efficient communication services to user equipment (UE) such as UAVs (150).

[0007] However, communication between NTN and UE may experience communication delay due to high altitude, and for example, there may be an inevitable delay in UE accessing NTN and obtaining TA information, and / or there may be a disadvantage in that battery consumption may be high.

[0008] In order to solve the above-described problem, one aspect of the present invention provides a method and a device therefor for performing communication by sharing TA information acquired by a specific UE with another UE through a side link.

[0009] Specifically, embodiments of the present invention propose conditions under which it is efficient to share TA information through a side link between UEs, and a method for sharing TA information through a side link.

[0010] In addition, in one embodiment of the present invention, a method is proposed to increase the time and / or success probability for random access by performing 2-Step Random Access (2-Step RACH) recently introduced in 3GPP by utilizing TA information sharing as described above.

[0011] In addition, embodiments of the present invention will explain situations in which the TA information described above is utilized, such as a situation in which a U2N (UE-to-Network) Relay UE and a remote UE exist, and a situation in which a UE group is formed.

[0012] The problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0013] In one aspect of the present invention for solving the above-described problem, a method for performing communication with a network by a second user equipment (UE) in a mobile communication system is proposed, comprising: receiving, from the second user equipment, TA (Timing Advance) information obtained by a first user equipment performing a random access procedure on the network through a sidelink; and performing communication with the network by utilizing the TA information, wherein receiving the TA information through the sidelink is performed when at least one of predetermined conditions including a first condition that the network includes a Non-Terrestrial Network (NTN) is satisfied.

[0014] At this time, the predetermined condition may include a second condition in which the network is a network in which the uplink TA information of the network changes at a time interval less than a predetermined standard, and a third condition in which a time or power greater than a predetermined standard is consumed to update the TA information of the network.

[0015] Additionally, receiving the TA information via the sidelink may include receiving it at the second user device via the first stage SCI (Sidelink Control Information) transmitted by the first user device.

[0016] Alternatively, receiving the TA information via the sidelink may include the second user device transmitting a TA information request message to the first user device; and receiving a response message in response to the TA information request message in the form of user data on a Sidelink - Shared Channel (SL-SCH).

[0017] Alternatively, receiving the TA information via the sidelink may include receiving it at the second user device via an S-MIB (Sidelink Master Information Block) transmitted by the first user device.

[0018] Meanwhile, performing communication with the network includes performing a two-step random access procedure with the network, and the first message of the two-step random access procedure can be transmitted using the TA information.

[0019] At this time, the first message of the two-step random access procedure may include information of the first message and the third message of the four-step random access (4-Step RACH) procedure.

[0020] In the embodiments described above, the first user device is a U2N (User-to-Network) relay user device, and the second user device can correspond to a remote user device.

[0021] In contrast, the first user device and the second user device belong to one user device group, and the first user device may correspond to a group head user device.

[0022]

[0023] Meanwhile, in another aspect of the present invention for solving the above-described problem, a method for a network to perform communication with a second user equipment (UE) in a mobile communication system is proposed, the method comprising: transmitting a random access response including TA (Timing Advance) information in response to random access preamble information received from a first user equipment; transmitting information indicating that the network satisfies at least one of predetermined conditions, including a first condition including a Non-Terrestrial Network (NTN), to the first user equipment and the second user equipment; and receiving an uplink signal transmitted to the network by the second user equipment using the TA information acquired from the first user equipment through a sidelink.

[0024] At this time, the predetermined condition may include a second condition in which the network's uplink TA information changes at a time interval less than a predetermined standard, and a third condition in which a time or power greater than a predetermined standard is consumed to update the network's TA information.

[0025] Additionally, information indicating that one or more of the above conditions are satisfied can be transmitted via an RRC (Radio Resource Control) message.

[0026] Additionally, receiving an uplink signal from the second user device may include performing a two-step random access procedure with the second user device, and a first message of the two-step random access procedure may be received using the TA information.

[0027] At this time, the first message of the two-step random access procedure may include information of the first message and the third message of the four-step random access procedure.

[0028] In the embodiments described above, the first user device may be a U2N (User-to-Network) relay user device, and the second user device may correspond to a remote user device.

[0029] In contrast, the first user device and the second user device belong to one user device group, and the first user device may correspond to a group head user device.

[0030] Meanwhile, in another aspect of the present invention, a device operating as a second user equipment (UE) performing communication with a network in a mobile communication system is proposed, comprising: 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, wherein the operations include receiving, via a sidelink, Timing Advance (TA) information obtained by a first user equipment performing a random access procedure on the network; and performing communication with the network using the TA information, wherein receiving the TA information via the sidelink is performed when at least one of predetermined conditions including a first condition that the network includes a Non-Terrestrial Network (NTN) is satisfied.

[0031] In addition, in another aspect of the present invention, a network for performing communication with a second user equipment (UE) in a mobile communication system is proposed, comprising: 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, wherein the operations include: transmitting a random access response including TA (Timing Advance) information in response to random access preamble information received from a first user equipment; transmitting information indicating that at least one of predetermined conditions including a first condition that the network includes a Non-Terrestrial Network (NTN) is satisfied to the first user equipment and the second user equipment; and receiving an uplink signal transmitted to the network by the second user equipment utilizing the TA information acquired from the first user equipment through a sidelink.

[0032] According to the embodiments of the present invention as described above, by sharing TA information acquired by a specific UE with another UE through a side link to perform communication, time delay and battery consumption for acquiring TA information can be reduced.

[0033] In addition, embodiments of the present invention provide predetermined conditions for sharing TA information through a side link between UEs under certain conditions, thereby enabling efficient sharing of TA information.

[0034] In addition, embodiments of the present invention specifically propose a method for sharing TA information through a side link, thereby efficiently performing TA information sharing according to the embodiments in an existing side link communication method.

[0035] In addition, in one embodiment of the present invention, by utilizing the TA information sharing as described above, the two-step random access recently introduced in 3GPP can be performed, thereby obtaining the effect of shortening the time for random access and / or increasing the success probability.

[0036] In addition, embodiments of the present invention specifically present situations in which the TA information described above is utilized, such as a situation in which a U2N (UE-to-Network) Relay UE and a remote UE exist, and a situation in which a UE group is formed, thereby enabling efficient identification of a TA information sidelink sharing situation.

[0037] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0038] Figure 1 is a drawing to explain the concept of NTN.

[0039] FIG. 2 is a diagram for explaining a concept of sharing TA information through a side link according to one embodiment of the present invention.

[0040] FIG. 3 is a diagram for explaining certain conditions under which TA information is shared via a side link according to one embodiment of the present invention.

[0041] FIG. 4 is a diagram illustrating a procedure for performing sidelink communication according to one embodiment of the present invention.

[0042] FIG. 5 is a diagram for explaining a two-step random access procedure using TA information sharing according to one embodiment of the present invention.

[0043] FIG. 6 is a diagram for explaining a situation in which a U2N Relay UE and a remote UE exist according to one embodiment of the present invention.

[0044] Figure 7 illustrates a wireless device to which the present technology can be applied.

[0045] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts irrelevant to the description have been omitted to clearly explain the present invention, and similar parts have been designated with similar reference numerals throughout the specification.

[0046] Throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0047] FIG. 2 is a diagram for explaining a concept of sharing TA information through a side link according to one embodiment of the present invention.

[0048] Referring to FIG. 2, a first user device (UE1) can perform a procedure (S210) for updating TA information to a network, specifically, a gNB, and for this purpose, UE 1 typically performs random access.

[0049] In this embodiment, if the network satisfies the first condition including NTN, or at least one of other predetermined conditions described below, it is proposed that UE 1 share the acquired TA information with UE 2 and UE 3 (S220, S230). By utilizing the shared TA information in this way, UE 2 and / or UE 3 can perform communication without a separate procedure for acquiring their own TA information from the network, thereby reducing communication delay and power consumption.

[0050] As illustrated in FIG. 2, the TA update procedure of UE 2 and / or UE 3 may be based on the TA information shared from UE 1 via the sidelink as described above (S240). Of course, UE 2 and / or UE 3 may independently perform TA information updates depending on their circumstances, but as described above, unnecessary delay and power consumption can be prevented by sharing TA information via the sidelink.

[0051] FIG. 3 is a diagram for explaining certain conditions under which TA information is shared via a side link according to one embodiment of the present invention.

[0052] As described above, in an NTN environment, when a UE obtains TA information through random access, etc., a large delay occurs compared to a general terrestrial network, and the battery consumption of the UE may be large. Therefore, in the embodiment described above with reference to FIG. 2, whether the network includes an NTN is presented as a first condition (310) and as a condition requiring TA information through a side link.

[0053] In this embodiment, even if the network does not include an NTN as in the first condition (310) described above, it is proposed to additionally consider a second condition (320) depending on whether TA information for uplink between the network and the UE changes at a time interval less than a predetermined standard, and a third condition (330) depending on whether time or power greater than a predetermined standard is consumed to update TA information between the network and the UE, and if at least one of these conditions is satisfied, it is proposed to set TA information to be shared via a sidelink (340).

[0054] For example, cases where a particular UE experiences significant delays in obtaining TA information and / or experiences significant battery drain (330) may exist in various cases other than when the network is an NTN. Furthermore, even in non-NTN cases, the TA change cycle may be very rapid, depending on the UE's / gNB's mobility speed.

[0055] Therefore, in this embodiment, it is proposed to set up TA information to be shared through a side link when one or more of the above conditions are satisfied.

[0056] If the network determines whether the above-described conditions are satisfied, the network can inform the service providing UEs of whether the TA information sidelink sharing conditions are satisfied, and can transmit this information, for example, through system information or an RRC message.

[0057] However, whether the above-described conditions are satisfied can be independently determined by the UE through information / signals received through the network.

[0058] Additionally, the time at which the first UE updates TA information and shares it via the sidelink may be set periodically, aperiodically, semi-statically, or semi-periodicly. In this case, the semi-periodic method adopts a periodic TA sharing method, but can be defined as a concept that allows this sharing mode to be turned ON / OFF.

[0059] Additionally, the frequency with which the first UE updates TA information via network access and whether the updated TA is shared via the sidelink each time may be configured differently. Specifically, whether the updated TA information is shared via the sidelink may be determined based on other predetermined criteria.

[0060]

[0061] FIG. 4 is a diagram illustrating a procedure for performing sidelink communication according to one embodiment of the present invention.

[0062] The embodiment of FIG. 4 can be combined with various embodiments of the present invention. In various embodiments of the present invention, the "transmission mode" may be referred to as a "mode" or a "resource allocation mode." Hereinafter, for convenience of explanation, the transmission mode in LTE may be referred to as the LTE transmission mode, and the transmission mode in NR may be referred to as the NR resource allocation mode.

[0063] Specifically, (a) of FIG. 4 shows terminal operation related to LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1. For example, LTE transmission mode 1 can be applied to general SL communication, and LTE transmission mode 3 can be applied to V2X communication.

[0064] Meanwhile, (b) of FIG. 4 shows terminal operation related to LTE transmission mode 2 or LTE transmission mode 4 or NR resource allocation mode 2.

[0065] Referring to (a) of FIG. 4, in LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, the base station may schedule SL resources to be used by a terminal for SL transmission (S8000). For example, the base station may transmit information related to SL resources and / or information related to UL resources to the first terminal. The UL resources may include PUCCH resources and / or PUSCH resources. In addition, the UL resources may be resources for reporting SL HARQ feedback to the base station.

[0066] A first terminal can receive information related to a dynamic grant (DG) resource and / or information related to a configured grant (CG) resource from a base station. The CG resource can include a CG type 1 resource or a CG type 2 resource. In this specification, a DG resource can be a resource that a base station configures / allocates to the first terminal via downlink control information (DCI). In addition, in this specification, a CG resource can be a (periodic) resource that a base station configures / allocates to the first terminal via DCI and / or an RRC message. For example, in the case of a CG type 1 resource, the base station can transmit an RRC message including information related to the CG resource to the first terminal. In the case of a CG type 2 resource, the base station can transmit an RRC message including information related to the CG resource to the first terminal, and the base station can transmit a DCI related to activation or release of the CG resource to the first terminal.

[0067] In step S8010, the first terminal may transmit a PSCCH (e.g., Sidelink Control Information (SCI) or 1st-stage SCI) to the second terminal based on the resource scheduling. In step S8020, the first terminal may transmit a PSSCH (e.g., 2nd-stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second terminal. In step S8030, the first terminal may receive a PSFCH (Physical Sidelink Feedback Channel) related to the PSCCH / PSSCH from the second terminal. For example, HARQ feedback information (e.g., NACK information or ACK information) may be received from the second terminal via the PSFCH. In step S8040, the first terminal may transmit / report HARQ feedback information to the base station via a PUCCH or a PUSCH. For example, the HARQ feedback information reported to the base station may be information generated by the first terminal based on the HARQ feedback information received from the second terminal. In addition, the HARQ feedback information reported to the base station may be information generated by the first terminal based on a rule set in advance. The DCI may be DCI for scheduling the SL. The format of the DCI may be DCI format 3_0 or DCI format 3_1.

[0068] Table 1 shows an example of DCI for scheduling SL.

[0069] [Table 1]

[0070]

[0071] Referring to (b) of FIG. 4, in LTE transmission mode 2, LTE transmission mode 4, or NR resource allocation mode 2, a terminal can determine an SL transmission resource within SL resources configured by a base station / network or preset SL resources. The configured SL resources or preset SL resources may be a resource pool. For example, the terminal can autonomously select or schedule resources for SL transmission. The terminal can perform SL communication by selecting resources within the configured resource pool. For example, the terminal can perform sensing and resource (re)selection procedures to select resources within a selection window. The sensing may be performed on a subchannel basis.

[0072] In step S8010, a first terminal that has selected a resource within a resource pool can transmit a PSCCH (e.g., Sidelink Control Information (SCI) or 1st-stage SCI) to a second terminal using the resource. In step S8020, the first terminal can transmit a PSSCH (e.g., 2nd-stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second terminal. In step S8030, the first terminal can receive a PSFCH related to the PSCCH / PSSCH from the second terminal.

[0073] Referring to (a) or (b) of FIG. 4, a first terminal may transmit an SCI to a second terminal on a PSCCH. Alternatively, the first terminal may transmit two consecutive SCIs (e.g., 2-stage SCIs) to the second terminal on the PSCCH and / or the PSSCH. In this case, the second terminal may decode the two consecutive SCIs (e.g., 2-stage SCIs) to receive the PSSCH from the first terminal. In this specification, an SCI transmitted on a PSCCH may be referred to as a 1st SCI, a 1st SCI, a 1st-stage SCI, or a 1st-stage SCI format, and an SCI transmitted on a PSSCH may be referred to as a 2nd SCI, a 2nd SCI, a 2nd-stage SCI, or a 2nd-stage SCI format. For example, a 1st-stage SCI format may include SCI format 1-A, and a 2nd-stage SCI format may include SCI format 2-A and / or SCI format 2-B.

[0074]

[0075] As described above, based on the sidelink communication method, in one embodiment of the present invention, sharing TA information via the sidelink as described above may correspond to a second terminal (UE) receiving 1st-stage SCI transmitted by a first terminal (UE). This 1st-stage SCI may be transmitted via a PSCCH, as illustrated in FIG. 4.

[0076] In another embodiment, sharing TA information via sidelink as described above may include the second terminal transmitting a TA information request message to the first terminal, and the second terminal receiving a response message in response to the TA information request message in the form of user data on a Sidelink-Shared Channel (SL-SCH). In this case, the SL-SCH may be transmitted via the PSSCH of FIG. 4, and reception thereof may be acknowledged via the PSFCH.

[0077] In another embodiment, sharing TA information via sidelink as described above may include receiving, at the second terminal, a Sidelink Master Information Block (S-MIB) transmitted by the first terminal. This S-MIB may be received via the PSBCH at the physical layer.

[0078] In addition, sharing of such TA information can be set to be shared via sidelink if the conditions described above in relation to FIG. 3 are satisfied, regardless of the above-described LTE transmission mode / NR resource allocation mode.

[0079]

[0080] FIG. 5 is a diagram for explaining a two-step random access procedure using TA information sharing according to one embodiment of the present invention.

[0081] First, there are the following cases where the terminal performs random access.

[0082] - When the terminal does not have an RRC connection with the base station and makes an initial access

[0083] - When the terminal first connects to the target cell during the handover process

[0084] - When a random access process is requested by a command from the base station

[0085] - When data to be transmitted through uplink occurs in a situation where the uplink time synchronization is not correct or the designated radio resources used to request radio resources are not allocated.

[0086] - When performing a recovery process in case of radio link failure or handover failure

[0087] Under this background, in the above-described embodiments, the terminal performing random access can be interpreted as a case in which the TA is updated due to a mismatch in uplink time synchronization.

[0088] In the LTE system, the process of selecting a random access preamble provides both a contention-based random access procedure, in which a terminal randomly selects and uses a preamble from a specific set, and a non-contention-based random access procedure, in which a base station uses a random access preamble allocated only to specific terminals. However, the non-contention-based random access procedure may only be used when requested by the above-described handover process or a command from the base station.

[0089] A non-contention-based random access process can be performed as follows:

[0090] (1) Random access preamble allocation

[0091] As described above, the non-contention-based random access process can be performed (1) during a handover process and (2) when requested by a base station command. Of course, the contention-based random access process can also be performed in both of the above cases.

[0092] First, for a contention-free random access process, it is crucial to receive a designated random access preamble from the base station that is collision-free. Methods for receiving this random access preamble include a handover command and a PDCCH command. Through these methods, the terminal is assigned a random access preamble.

[0093] (2) Transmitting the first message

[0094] After the terminal is assigned a random access preamble designated only to itself as described above by the base station, the terminal transmits the preamble to the base station.

[0095] (3) Receiving the second message

[0096] After the terminal transmits the random access preamble as in the above-described step (2), the base station attempts to receive its own random access response within the random access response reception window indicated by the system information or handover command. More specifically, the random access response information may be transmitted in the form of a MAC Packet Data Unit (MAC PDU), and the MAC PDU may be transmitted through a Physical Downlink Shared CHaneel (PDSCH). In addition, it is preferable that the terminal monitor the Physical Downlink Control CHaneel (PDCCH) in order to properly receive the information transmitted through the PDSCH. That is, the PDCCH preferably includes information on the terminal that must receive the PDSCH, frequency and time information of the radio resources of the PDSCH, and the transmission format of the PDSCH. Once the terminal successfully receives the PDCCH transmitted to itself, it can properly receive the random access response transmitted through the PDSCH according to the information of the PDCCH. And the random access response may include a random access preamble identifier (ID; for example, RA-RNTI (Random Access Radio Network Temporary Identifier)), an uplink grant (UL Grant) indicating uplink radio resources, a temporary cell identifier (Temporary C-RNTI), and a time synchronization correction value (Timing Advance Command: TAC).

[0097] As described above, the reason why a random access preamble identifier is required in a random access response is that a single random access response may include random access response information for one or more terminals, and thus it is necessary to indicate to which terminal the uplink grant (UL Grant), temporary C-RNTI, and TAC are valid. In this step, it is assumed that the terminal selects a random access preamble identifier that matches the random access preamble it selected in step S402.

[0098] In a non-contention-based random access process, the random access process can be determined to have been performed normally by receiving random access response information and the random access process can be terminated.

[0099]

[0100] However, as described above, the non-contention-based random access process can be performed in limited circumstances, and generally can be performed through a contention-based random access process as illustrated in the drawing reference numeral 510 of FIG. 5.

[0101] The process by which a terminal performs random access with a specific base station may largely include (1) a step of transmitting a random access preamble by the terminal to the base station (hereinafter, a "first message (message 1)" transmission step if there is no confusion), (2) a step of receiving a random access response from the base station in response to the transmitted random access preamble (hereinafter, a "second message (message 2)" reception step if there is no confusion), (3) a step of transmitting an uplink message using information received in the random access response message (hereinafter, a "third message (message 3)" transmission step if there is no confusion), and (4) a step of receiving a message corresponding to the uplink message from the base station (hereinafter, a "fourth message (message 4)" reception step if there is no confusion).

[0102] (1) Transmitting the first message

[0103] First, the terminal can randomly select one random access preamble from a set of random access preambles indicated through system information or a handover command, and select a PRACH (Physical RACH) resource capable of transmitting the random access preamble to transmit it (step 1).

[0104] (2) Receiving the second message

[0105] The method for receiving random access response information is similar to the non-contention-based random access process described above. That is, after the terminal transmits the random access preamble as in step 1, the terminal attempts to receive its own random access response within the random access response reception window indicated by the base station through system information or a handover command, and receives the PDSCH through the corresponding RA-RNTI information (step 2). Through this, an uplink grant (UL Grant), a temporary cell identifier (Temporary C-RNTI), and a time synchronization correction value (Timing Advance Command: TAC) can be received.

[0106] (3) Third message transmission

[0107] When a terminal receives a valid random access response, it processes the information contained in the random access response. That is, the terminal applies the TAC and stores the temporary C-RNTI. In addition, it transmits data (i.e., the third message) to the base station using the UL authorization (step 3). The third message must include the terminal identifier. In a contention-based random access process, the base station cannot determine which terminals are performing the random access process, because the terminals must be identified for later collision resolution.

[0108] Two methods for including a terminal identifier have been discussed. In the first method, if the terminal already has a valid cell identifier assigned to the cell before the random access procedure, the terminal transmits its cell identifier via the uplink transmission signal corresponding to the UL grant. On the other hand, if the terminal has not been assigned a valid cell identifier before the random access procedure, the terminal transmits including its own unique identifier (e.g., S-TMSI or Random ID). Typically, the unique identifier is longer than the cell identifier. If the terminal transmits data corresponding to the UL grant, it starts a timer for contention resolution (contention resolution timer).

[0109] (4) Receiving the 4th message

[0110] After the terminal transmits data including its own identifier through the UL grant included in the random access response, it waits for instructions from the base station for collision resolution. That is, it attempts to receive the PDCCH to receive a specific message (step 4). Two methods have been discussed for receiving the PDCCH. As mentioned above, if the third message transmitted in response to the UL grant uses its own identifier as its cell identifier, it attempts to receive the PDCCH using its own cell identifier, and if the identifier is a unique identifier, it may attempt to receive the PDCCH using the temporary C-RNTI included in the random access response. In the former case, if the PDCCH is received through its own cell identifier before the collision resolution timer expires, the terminal determines that the random access process has been performed normally and terminates the random access process. In the latter case, if the PDCCH is received through the temporary C-RNTI before the collision resolution timer expires, the terminal checks the data transmitted by the PDSCH indicated by the PDCCH. If the content of the above data contains its own unique identifier, the terminal determines that the random access process has been performed normally and terminates the random access process.

[0111]

[0112] Meanwhile, the drawing reference numeral 520 of FIG. 5 illustrates the concept of a two-stage random access that is distinct from the non-contention-based random access and contention-based four-stage random access described above.

[0113] This two-step random access is a random access process introduced in Release 16 of NR, and as illustrated in FIG. 5, the message A initially transmitted by the terminal to the base station is characterized by being transmitted including the first message and the third message in the four-step random access of drawing reference numeral 510 (step A).

[0114] Additionally, in the two-step random access process, the base station may respond to the terminal with message B, which is characterized in that it is transmitted including the second message and the fourth message in the four-step random access of drawing reference numeral 510 (step B).

[0115] This has the advantage of simplifying the four-step random access process into two steps, allowing for faster random access, but has the disadvantage of a low probability of success in random access, because message A in the two-step random access is transmitted without considering TA information, i.e., the TAC received through the second message in the four-step random access process.

[0116] However, in a situation where a terminal is sharing TA information acquired by another terminal through a side link as described above with respect to FIGS. 2 to 4, the probability of successful transmission of message A in the two-step random access process of FIG. 5 may increase, and thus random access may be completed more quickly.

[0117] In the above-described two-step random access process (520), the two transmission messages are referred to as 'message A' and 'message B' to distinguish them from the four transmission messages in the four-step random access process (510). However, if there is no confusion, they may be referred to as the 'first message' and 'second message' of the two-step random access process according to the order.

[0118]

[0119] Below, situations in which the TA information described above is utilized are described, such as a situation in which a U2N (UE-to-Network) Relay UE and a remote UE exist, and a situation in which a UE group is formed.

[0120] FIG. 6 is a diagram for explaining a situation in which a U2N Relay UE and a remote UE exist according to one embodiment of the present invention.

[0121] A U2N relay situation refers to a situation where a remote UE has difficulty communicating directly with the network (specifically, gNB) and receives the relevant information through a U2N Relay UE.

[0122] That is, in the above-described embodiment, the UE that obtains TA information from the gNB on its own is a U2N Relay UE, and the UE that receives it through a side link can respond in the case where it is a remote UE.

[0123] In step 1 of FIG. 6, the U2N remote UE and the U2N Relay UE perform a discovery procedure and can perform a PC5 RRC connection based on this.

[0124] In step 2, the remote UE may send an RRC Setup request message (also known as RRCReestablishmentRequest, or RRCResumeRequest) to the gNB via the PC5 RRC connected Relay UE.

[0125] Based on this, PC5 and Uu RLC channels for SRB1 can be prepared in step 3. In this embodiment, it is proposed that the relay UE transmits the TA information obtained from the gNB through the PC5 interface.

[0126] In step 4, the gNB may send an RRC Setup Complete message to the remote UE via the Relay UE based on the information received in step 2.

[0127] Afterwards, in step 5, settings related to security mode can be performed, and in step 6, RRC reconfiguration procedures can be performed to suit the SRB2 / DRBs to the U2N Relay situation.

[0128]

[0129] Meanwhile, in another embodiment of the present invention, the UEs as described above belong to one UE group, and a UE that updates TA information by itself through a gNB corresponds to a group head, and a UE that shares this may be utilized in a form corresponding to a UE supported by the group head.

[0130]

[0131] Figure 7 illustrates a wireless device to which the present technology can be applied.

[0132] Referring to FIG. 7, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals via various wireless access technologies (e.g., LTE, NR). Here, the first wireless device (100) and the second wireless device (200) may correspond to UE 1 and UE 2 of FIG. 2, respectively, or may correspond to UE1 and gNB of FIG. 2.

[0133] 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 the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (102) may process information in the memory (104) to generate first information / signal, and then transmit a wireless signal including the first information / signal via the transceiver (106). In addition, the processor (102) may receive a wireless signal including second information / signal via the transceiver (106), and then store information obtained from signal processing of the second information / signal 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 descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE E-UTRA, 5G 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 the present invention, a wireless device may also mean a communication modem / circuit / chip.

[0134] 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 descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. 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). Furthermore, 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 store software code including commands for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods and / or operation flowcharts disclosed in this document. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE E-UTRA, 5G 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 the present invention, a wireless device may also mean a communication modem / circuit / chip.

[0135] Hereinafter, the 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 PHY, MAC, RLC, PDCP, RRC, SDAP). 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 descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors (102, 202) can 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 herein, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can 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 descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0136] 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 descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software configured to perform 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 descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0137] 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.

[0138] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or flowcharts of this document, to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts of this document, from one or more other devices. For example, one or more transceivers (106, 206) can be connected to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can 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 receive user data, control information, wireless signals / channels, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein, via one or more antennas (108, 208). In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. 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.

[0139]

[0140] The detailed description of the preferred embodiments of the present invention disclosed above has been provided to enable those skilled in the art to implement and practice the present invention. While the above description has been made with reference to preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the scope of the present invention. For example, those skilled in the art can utilize the individual components described in the above-described embodiments in combination with each other.

[0141] Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0142] The method for sharing TA information through a side link according to the embodiments of the present invention as described above and the device therefor are suitable for use in the NTN application environment discussed in 3GPP, but as described above, they can also be widely used in various situations where individual acquisition of TA information is difficult in communication methods other than 3GPP.

Claims

1. In a method for a second user equipment (UE) to perform communication with a network in a mobile communication system, The first user device receives TA (Timing Advance) information obtained by performing a random access procedure to the network from the second user device through a sidelink; and Including the second user device performing communication with the network by utilizing the TA information, Receiving the above TA information via sidelink, A method of communicating with a network, performed when the network satisfies at least one of predetermined conditions including a first condition that the network includes a Non-Terrestrial Network (NTN).

2. In paragraph 1, The above conditions are, A second condition is a situation in which TA information between the above network and the second user device changes at a time interval less than a predetermined standard. A method for communicating with a network, comprising a third condition that a predetermined standard or more of time or power is consumed to update TA information between the network and the second user device.

3. In paragraph 1, Receiving the above TA information via sidelink, A method of communicating with a network, comprising receiving from a second user device a first step SCI (Sidelink Control Information) transmitted by the first user device.

4. In paragraph 1, Receiving the above TA information via sidelink, The second user device transmits a TA information request message to the first user device; A method for communicating with a network, comprising receiving a response message in response to the above TA information request message in the user data format of SL-SCH (Sidelink - Shared Channel).

5. In paragraph 1, Receiving the above TA information via sidelink, A method of communicating with a network, comprising receiving from a second user device an S-MIB (Sidelink Master Information Block) transmitted by the first user device.

6. In paragraph 1, Performing communication with the above network, Including performing the above network and the two-step random access procedure, A method of communicating with a network, wherein the first message of the above two-step random access procedure is transmitted using the above TA information.

7. In paragraph 6, The first message of the above two-step random access procedure is, A method of communicating with a network, comprising information of a first message and a third message of a four-step random access procedure.

8. In paragraph 1, The above first user device is a U2N (User-to-Network) relay user device, A method for communicating with a network, wherein the second user device corresponds to a remote user device.

9. In paragraph 1, The above first user device and the above second user device belong to one user device group, A method for communicating with a network, wherein the first user device corresponds to a group head user device.

10. In a method for a network to perform communication with a second user equipment (UE) in a mobile communication system, Transmitting a random access response including TA (Timing Advance) information in response to random access preamble information received from a first user device; When the above network satisfies at least one of the predetermined conditions including the first condition that the above network includes a Non-Terrestrial Network (NTN), information indicating that at least one of the predetermined conditions is satisfied is transmitted to the first user device and the second user device; and A communication method of a network, comprising receiving an uplink signal transmitted to the network by the second user device using the TA information acquired from the first user device through a sidelink.

11. In Article 10, The above conditions are, A second condition is that the network is one in which TA information between the above network and the second user device changes at a time interval less than a predetermined standard; A method of communication in a network, comprising a third condition that a predetermined standard or more of time or power is consumed to update TA information between the network and the second user device.

12. In paragraph 10, A network communication method in which information indicating that one or more of the above conditions are satisfied is transmitted through system information or an RRC (Radio Resource Control) message.

13. In paragraph 10, Receiving an uplink signal from the second user device, Comprising performing a two-step random access procedure with the second user device, A communication method of a network, wherein the first message of the above two-step random access procedure is received by utilizing the above TA information.

14. In paragraph 13, The first message of the above two-step random access procedure is, A method of communication in a network, comprising information of a first message and a third message of a four-step random access procedure.

15. In paragraph 10, The above first user device is a U2N (User-to-Network) relay user device, A method of communication in a network, wherein the second user device corresponds to a remote user device.

16. In paragraph 10, The above first user device and the above second user device belong to one user device group, A network communication method, wherein the first user device corresponds to a group head user device.

17. In a device that operates as a second user equipment (UE) that performs network and communication in a mobile communication system, 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; The above actions are, The first user device receives TA (Timing Advance) information obtained by performing a random access procedure to the network through a sidelink; and Including performing communication with the network by utilizing the above TA information, Receiving the above TA information via sidelink, A user device device, which is performed when the above network satisfies any one or more of the predetermined conditions including the first condition that the above network includes a Non-Terrestrial Network (NTN).

18. In a network that performs communication with a second user equipment (UE) in a mobile communication system, 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; The above actions are, Transmitting a random access response including TA (Timing Advance) information in response to random access preamble information received from a first user device; When the above network satisfies at least one of the predetermined conditions including the first condition that the above network includes a Non-Terrestrial Network (NTN), information indicating that at least one of the predetermined conditions is satisfied is transmitted to the first user device and the second user device; and A network comprising: receiving an uplink signal transmitted to the network by the second user device utilizing the TA information acquired from the first user device via a sidelink.

Images