Method and apparatus for transmitting and receiving broadcast information in a wireless communication system

Abstract

The disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system and an Internet of Things (IoT) technology beyond a 4th-Generation (4G) system supporting higher data rates. The disclosure can be applied to intelligent services based on 5G communication technologies and IoT-related technologies, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Methods and apparatuses for transmitting and receiving broadcast information in a wireless communication system are disclosed.

Description

Technical Field

[0001] This disclosure generally relates to a method for transmitting and receiving broadcast information in a wireless communication system, and more specifically, to a method and apparatus for configuring the transmission and reception of broadcast information in a sidelink communication system. Background Technology

[0002] To meet the increased demand for wireless data traffic since the deployment of fourth-generation (4G) communication systems, efforts have been made to develop improved fifth-generation (5G) or pre-5G communication systems, also known as super 4G networks or post-Long Term Evolution (LTE) systems. The 5G communication systems established by the 3rd Generation Partnership Project (3GPP) are referred to as New Radio (NR) systems.

[0003] 5G communication systems are envisioned to be implemented in higher frequency millimeter-wave (mmWave) bands (e.g., the 60 GHz band) to achieve higher data rates. To reduce radio wave propagation loss and increase transmission distance, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies have been discussed and adopted in 5G communication systems.

[0004] Furthermore, in 5G communication systems, development is underway to improve system networks based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multipoint (CoMP), and receiver interference cancellation. In 5G systems, hybrid frequency shift keying (FSK), orthogonal amplitude modulation (FQAM), and sliding window superposition coding (SWSC) have been developed as advanced coding and modulation (ACM), while filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) have been developed as advanced access technologies.

[0005] The internet is now evolving into the Internet of Things (IoT), in which distributed entities (such as things) exchange and process information without human intervention. The Internet of Everything (IoE), which combines IoT technology with big data processing technology through connection to cloud servers, has also emerged. Because IoT implementation requires technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology, sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC) have recently been studied. Such an IoT environment can provide intelligent internet technology services, creating new value for human life by collecting and analyzing data generated between interconnected things. Through the convergence and integration of existing information technology (IT) and various industrial applications, IoT can be applied to a wide range of fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0006] Therefore, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, MTC, and M2M communication can be implemented through beamforming, MIMO, and array antennas. Cloud radio access networks (RAN), as an application of the aforementioned big data processing technologies, can also be considered an example of the convergence between 5G and IoT technologies.

[0007] With the development of mobile communication systems, a wide variety of services can now be provided. However, existing technologies lack efficiency in the process of configuring, sending, and receiving sidelink broadcast information in sidelink communication systems.

[0008] Therefore, a more efficient way to provide this service is needed. Summary of the Invention

[0009] Technical issues

[0010] There is a need to effectively provide various services in next-generation wireless communication systems.

[0011] Problem Solution

[0012] This disclosure is provided to address at least the aforementioned problems and / or disadvantages, and to provide at least the following advantages.

[0013] Therefore, one aspect of this disclosure is to provide a method for configuring broadcast information in a sidelink communication system, and a method and apparatus for sending and receiving broadcast information.

[0014] Another aspect of this disclosure is to provide a more efficient process for configuring, sending, and receiving sidelink broadcast messages in a sidelink communication system.

[0015] According to one aspect of this disclosure, a method performed by a first terminal includes sending time slot format information for sidelink communication to a second terminal on a physical sidelink broadcast channel. The time slot format information includes first information regarding the number of modes, second information regarding the mode period, and third information regarding the number of uplink time slots for the mode. The method also includes performing sidelink communication with the second terminal in at least one sidelink resource identified based on the first, second, and third information. Specifically, when the first information indicates that the number of modes is 1, the second information indicates the mode period of the mode, and the third information indicates the number of uplink time slots for that mode. Furthermore, when the first information indicates that the number of modes is 2, the second information indicates the period of both the first and second modes, and the third information indicates the number of uplink time slots for both the first and second modes.

[0016] According to another aspect of this disclosure, a method performed by a second terminal in a wireless communication system includes: receiving, on a PSBCH, time slot format information for sidelink communication from a first terminal, the time slot format information including first information about the number of modes, second information about the mode period, and third information about the number of uplink time slots for the mode; and performing sidelink communication with the first terminal in at least one sidelink resource identified based on the first, second, and third information, wherein, when the first information indicates that the number of modes is 1, the second information indicates the mode period of the mode, and the third information indicates the number of uplink time slots for the mode; and wherein, when the first information indicates that the number of modes is 2, the second information indicates the period of a first mode and a second mode, and the third information indicates the number of uplink time slots for the first and second modes.

[0017] According to another aspect of this disclosure, a first terminal includes: a transceiver configured to transmit and receive signals; and a controller configured to transmit slot format information for sidelink communication to a second terminal on the PSBCH, the slot format information including first information about the number of modes, second information about the mode period, and third information about the number of uplink slots for the mode, and to perform sidelink communication with the second terminal in at least one sidelink resource identified based on the first, second, and third information, wherein when the first information indicates that the number of modes is 1, the second information indicates the mode period of the mode, and the third information indicates the number of uplink slots for the mode, and wherein when the first information indicates that the number of modes is 2, the second information indicates the period of the first mode and the second mode, and the third information indicates the number of uplink slots for the first mode and the second mode.

[0018] According to another aspect of this disclosure, the second terminal includes: a transceiver configured to transmit and receive signals; and a controller configured to receive, on the PSBCH, time slot format information for sidelink communication from the first terminal, the time slot format information including first information about the number of modes, second information about the mode period, and third information about the number of uplink time slots for the mode, and to perform sidelink communication with the first terminal in at least one sidelink resource identified based on the first, second, and third information, wherein, when the first information indicates that the number of modes is 1, the second information indicates the mode period of the mode, and the third information indicates the number of uplink time slots for the mode, and wherein, when the first information indicates that the number of modes is 2, the second information indicates the period of the first mode and the second mode, and the third information indicates the number of uplink time slots for the first mode and the second mode.

[0019] Beneficial effects of the invention

[0020] According to embodiments of this disclosure, a variety of services of next-generation wireless communication systems can be effectively provided. Attached Figure Description

[0021] The above and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, wherein:

[0022] Figures 1A, 1B, 1C and 1D illustrate systems that apply this disclosure;

[0023] Figures 2A and 2B illustrate a vehicle-to-everything (V2X) communication method performed via a side link using the present disclosure;

[0024] Figure 3 The protocol of the sidelink terminal applying this disclosure is shown;

[0025] Figure 4 The types of synchronization signals that a sidelink terminal applying this disclosure can receive are shown;

[0026] Figure 5 The frame structure of the side link system according to an embodiment is shown;

[0027] Figure 6 The structure of the side-link synchronization channel according to an embodiment is shown;

[0028] Figure 7A illustrates a method for transmitting a sidelink synchronization signal according to a first embodiment;

[0029] Figure 7B illustrates a method for transmitting a sidelink synchronization signal according to a second embodiment;

[0030] Figure 8A method for transmitting a sidelink synchronization signal according to a third embodiment is shown;

[0031] Figure 9 An uplink-downlink configuration in base station coverage according to an embodiment is shown;

[0032] Figure 10 The number of uplink-downlink symbols occupied by 14 symbols constituting a time slot, according to an embodiment, is shown.

[0033] Figure 11 This illustrates the sending and receiving of information between sidelink terminals according to an embodiment;

[0034] Figure 12 The link types through which a sidelink terminal can perform sidelink communication according to an embodiment are shown;

[0035] Figure 13 The side link synchronization process according to the first embodiment is shown;

[0036] Figure 14 The side link synchronization process according to the second embodiment is shown;

[0037] Figure 15 The structure of the terminal according to an embodiment is shown;

[0038] Figure 16 The structure of a base station according to an embodiment is shown;

[0039] Figure 17 The illustration shows sidelink resource information received by a sidelink terminal according to an embodiment;

[0040] Figure 18 A method for setting sidelink resource information according to an embodiment is shown; and

[0041] Figure 19 The time slot structure of the subcarrier spacing according to an embodiment is shown. Detailed Implementation

[0042] Embodiments of this disclosure will be described in detail with reference to the accompanying drawings. For clarity and brevity, detailed descriptions of known functions and / or configurations will be omitted.

[0043] Some elements in the accompanying drawings may be exaggerated, omitted, or shown schematically, and the dimensions of each element do not perfectly reflect the actual dimensions. In the accompanying drawings, identical or corresponding elements are indicated by the same reference numerals.

[0044] The advantages and features of this disclosure, as well as the ways in which they are implemented, will become apparent from the embodiments described below with reference to the accompanying drawings. This disclosure may be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided as examples to fully convey the scope of this disclosure to those skilled in the art.

[0045] This disclosure will be described in accordance with the 5G mobile communication standards specified by the 3GPP mobile communication standardization organization, focusing on NR networks and packet cores (i.e., 5G System (5GS), 5G core network, or Next Generation (NG) core). However, with minor modifications, the subject matter of this disclosure can also be applied to other communication systems with similar technical backgrounds without departing from the scope of this disclosure.

[0046] In 5G systems, network data collection and analysis functions (NWDAFs) can be defined to collect, analyze, and provide data within the 5G network to support network automation. NWDAFs can collect, store, and analyze information from the 5G network and provide analysis results to unspecified network functions (NFs). The analysis results can be used independently within each NF.

[0047] For ease of description, some terms and names defined in the 3GPP standards will be used. However, this disclosure is not limited to these terms and names and can be applied to any other system conforming to any other standard.

[0048] For convenience, terms used to identify access nodes and refer to network entities, messages, interfaces between network entities, and various identifying information are used illustratively. Therefore, this disclosure is not limited to the terms used below, and other terms relating to subjects with equivalent technical meaning may be used.

[0049] In 5G communication systems, numerous services can be provided to users. Therefore, a method and apparatus are needed to provide these services within equal time intervals. One such service provided in 5G communication systems is one that meets the requirements of low latency and high reliability.

[0050] In vehicle communications, based on the D2D communication architecture, LTE-based V2X communication has been standardized in 3GPP Rel-14 and Rel-15. Efforts are underway to develop 5G NR-based V2X communication, where unicast, multicast (or multi-cast), and broadcast communication will be supported between terminals. Unlike LTE V2X communication, which is designed to send and receive basic safety information required for on-road driving, NR V2X communication aims to provide more advanced services such as platooning, advanced driving, extended sensors, and remote driving.

[0051] The aforementioned advanced services require high data rates; therefore, 5G NR V2X systems may require relatively wider bandwidth compared to traditional 4G LTE V2X systems. Consequently, it is necessary to support operation in high-frequency bands and address coverage issues caused by frequency characteristics through simulated beamforming. In such simulated beamforming systems, a method and apparatus are needed for acquiring beam information between the transmitting and receiving terminals.

[0052] Figures 1A, 1B, 1C and 1D illustrate systems that apply this disclosure.

[0053] Figure 1A shows a scenario within the coverage area, where all V2X terminals, namely UE-1 and UE-2, are within the coverage area of ​​the base station (gNB, eNB, roadside unit (RSU)).

[0054] All V2X UEs can receive data and control information from the base station via the downlink (DL) and transmit data and control information to the base station via the uplink (UL). This data and control information can be used for V2X communication or general cellular communication. Furthermore, V2X UEs can send and receive data and control information for V2X communication via the sidelink (SL).

[0055] Figure 1B shows a partial coverage scenario, where in a V2X UE, UE-1 is within the coverage area of ​​the base station, and UE-2 is outside the coverage area.

[0056] UE-1, located within the coverage area of ​​a base station, can receive data and control information from the base station via the downlink and send data and control information to the base station via the uplink.

[0057] UE-2 located outside the coverage area of ​​the base station cannot receive data and control information from the base station via the downlink, nor can it send data and control information to the base station via the uplink.

[0058] UE-2 can send and receive data and control information for V2X communication to and from UE-1 via a side link.

[0059] Figure 1C illustrates a scenario outside the coverage area, where all V2X UEs are located outside the base station's coverage area.

[0060] In scenario (c), UE-1 and UE-2 cannot receive data and control information from the base station via the downlink, nor can they send data and control information to the base station via the uplink.

[0061] UE-1 and UE-2 can send and receive data and control information for V2X communication via sidelink.

[0062] Figure 1D illustrates an inter-cell V2X communication scenario where UEs located in different cells perform V2X communication with each other. Specifically, in scenario (d), the V2X transmitting UE and the V2X receiving UE are connected to different base stations (i.e., Radio Resource Control (RRC) connected state) or camped in different cells (i.e., RRC connected released state or RRC idle state). In this case, UE-1 can be a V2X transmitting UE, and UE-2 can be a V2X receiving UE. Alternatively, UE-1 can be a V2X receiving UE, and UE-2 can be a V2X transmitting UE. UE-1 can receive V2X Dedicated System Information Blocks (SIBs) from the base station to which UE-1 is connected (or from the base station of the cell where UE-1 camps), and UE-2 can receive V2X Dedicated SIBs from another base station to which UE-2 is connected (or from the base station of the cell where UE-2 camps). The information in the V2X Dedicated SIBs received by UE-1 and UE-2 can be the same or different from each other. In the latter case, UE-1 and UE-2 may each receive different information for sidelink communication from the base stations they are connected to (or camped on). In this case, unified information is needed to enable sidelink communication between UEs located in different cells.

[0063] Although Figures 1A, 1B, 1C, and 1D illustrate a V2X system consisting of two UEs (UE-1 and UE-2) for ease of description, this is merely an example. Furthermore, the uplink and downlink between the base station and the V2X UE can be referred to as the Uu interface, and the sidelink between the V2X UEs can be referred to as the PC5 interface. Therefore, these terms are used interchangeably in this disclosure.

[0064] In this document, a terminal that can be used interchangeably with a UE can refer to a device supporting device-to-device (D2D) communication, a vehicle supporting vehicle-to-vehicle (V2V) communication, a vehicle supporting vehicle-to-pedestrian (V2P) communication or a pedestrian's handheld device (e.g., a smartphone), a vehicle supporting vehicle-to-network (V2N) communication, or a vehicle supporting vehicle-to-infrastructure (V2I) communication. Furthermore, a terminal or UE can refer to an RSU with UE functionality, an RSU with base station functionality, or an RSU with a portion of base station functionality and a portion of UE functionality.

[0065] V2X communication can refer to D2D communication, V2V communication, or V2P communication, and can be used interchangeably with sidelink communication.

[0066] A base station may support both V2X and general cellular communications, or it may support only V2X communications. Furthermore, a base station may refer to a 5G base station (i.e., gNB), a 4G base station (i.e., eNB), or an RSU. Therefore, unless otherwise stated in this disclosure, the above terms related to base stations are used interchangeably.

[0067] Figures 2A and 2B illustrate the V2X communication method performed via a side link using the present disclosure.

[0068] As shown in Figure 2A, the sending UE (UE-1) and receiving UE (UE-2) can perform one-to-one communication, which can be called unicast communication.

[0069] In Figure 2B, the sending UE (UE-1 or UE-4) and the receiving UE (UE-2 and UE-3, or UE5, UE-6 and UE-7) can perform one-to-many communication, which can be referred to as multicast or multicast communication.

[0070] In Figure 2B, UE-1, UE-2, and UE-3 form one group (Group A) and perform multicast communication, while UE-4, UE-5, UE-6, and UE-7 form another group (Group B) and perform another multicast communication. Each UE performs multicast communication only within its group. Inter-group communication can be performed via unicast, multicast, or broadcast communication. Although Figure 2B shows two groups, this disclosure is not limited thereto.

[0071] V2X UEs can perform broadcast communication, where all V2X UEs receive data and control information sent by the V2X transmitting UE via a sidelink. For example, in Figure 2B, when UE-1 is assumed to be the transmitting UE for broadcasting, all other UEs (i.e., UE-2, UE-3, UE-4, UE-5, UE-6, and UE-7) can be receiving UEs that receive data and control information sent by UE-1.

[0072] The sidelink unicast, multicast, and broadcast communication methods according to embodiments of this disclosure can be supported in scenarios with coverage, partial coverage, and outside coverage.

[0073] In a sidelink system, resource allocation can be performed using the following methods.

[0074] (1) Mode 1 resource allocation

[0075] This refers to the resource allocation method scheduled by the base station (scheduled resource allocation). Specifically, the base station can allocate resources for sidelink transmission to RRC-connected UEs in a dedicated scheduling scheme. The scheduled resource allocation method may be effective for interference management and resource pool management (e.g., dynamic allocation and / or semi-persistent scheduling (SPS)) because the base station can manage sidelink resources. When there is data to be sent to other(multiple) UEs, the RRC-connected UE can use an RRC message or a Media Access Control (MAC) control element (CE) to notify the base station of the existence of data to be sent to other(multiple) UEs. For example, the RRC message can be a sidelink UE information message or a UE assistance information message. Furthermore, the MAC CE can be a buffer status report (BSR) MAC CE, a scheduling request (SR), etc., including at least one of an indicator indicating the BSR used for V2X communication and information about the size of the data buffered for sidelink communication. Because the base station schedules resources for sidelink transmitting UEs, the Mode 1 resource allocation method can be applied when the V2X transmitting UE is within the base station's coverage area.

[0076] (2) Mode 2 resource allocation

[0077] Mode 2 allows sidelink transmitting UEs to autonomously select resources (UE-autonomous resource selection). Specifically, the base station provides the UE with a sidelink transmit / receive resource pool for sidelink use via system information or RRC messages (e.g., RRCReconfiguration messages or PC5-RRC messages), and the transmitting UE receiving the transmit / receive resource pool selects the resource pool and resources according to predetermined rules. Because the base station provides configuration information about the sidelink transmit / receive resource pool, the Mode 2 resource allocation method can be applied when the sidelink transmitting and receiving UEs are within the base station's coverage area. If the sidelink transmitting and receiving UEs are outside the base station's coverage area, both UEs can perform Mode 2 operations within a pre-configured transmit / receive resource pool. UE-autonomous resource selection methods may include area mapping, awareness-based resource selection, random selection, etc.

[0078] (3) Even if the UE is within the coverage area of ​​the base station, it may not perform resource allocation or resource selection in the scheduling resource allocation mode or the UE autonomous resource selection mode. In this case, the UE can perform sidelink communication through the pre-configured sidelink transmit / receive resource pool.

[0079] Figure 3 The protocol of the sidelink terminal using this disclosure is shown.

[0080] The application layer of UE-A and UE-B can perform service discovery to determine which sidelink communication scheme (unicast, multicast, or broadcast) each UE will execute. Figure 3 In this scenario, it is assumed that UE-A and UE-B recognize that they will execute a unicast communication scheme through the service discovery process performed in their application layers. Sidelink UEs can obtain information about the source identifier (ID) and destination ID of the sidelink communication during the service discovery process.

[0081] When the service discovery process is complete Figure 3 The PC-5 signaling protocol layer shown can perform the D2D direct link connection establishment process. In this case, security settings information for D2D direct communication can be exchanged.

[0082] When the D2D direct link connection establishment process is complete, it can be Figure 3 The D2D PC-5RRC establishment process is performed in the PC-5RRC layer. In this case, information about the capabilities of UE-A and UE-B can be exchanged, and access layer (AS) parameter information for unicast communication can also be exchanged.

[0083] Once the PC-5RRC establishment process is complete, UE-A and UE-B can perform unicast communication.

[0084] While the above example illustrates unicast communication, it can be extended to multicast communication. For instance, when UE-A, UE-B, and UE-C perform multicast communication, UE-A and UE-B can perform the unicast service discovery, D2D direct link establishment, and PC-5RRC establishment procedures as described above. Furthermore, UE-A and UE-C can perform the unicast service discovery, D2D direct link establishment, and PC-5RRC establishment procedures. Similarly, UE-B and UE-C can perform the unicast service discovery, D2D direct link establishment, and PC-5RRC establishment procedures. That is, instead of performing a separate PC-5RRC establishment procedure for multicast communication, each pair of transmitting / receiving UEs participating in multicast communication can perform the unicast PC-5RRC establishment procedure. However, in multicast methods, it may not always be necessary to perform the unicast PC5 RRC establishment procedure. For example, there may be cases where multicast communication is performed without a PC5 RRC connection being established; in such cases, the unicast PC5 RRC establishment procedure can be omitted.

[0085] The PC-5RRC establishment process for unicast or multicast communication can be applied to all coverage, partial coverage, and out-of-coverage scenarios shown in Figure 1. When the UE performing unicast or multicast communication is within the coverage area of ​​the base station, the UE can perform the PC-5RRC establishment process before or after performing downlink or uplink synchronization with the base station.

[0086] Figure 4 The types of synchronization signals that a sidelink terminal applying this disclosure can receive are shown.

[0087] Specifically, the following sidelink synchronization signals can be received from various sidelink synchronization sources.

[0088] - The side-link UE can receive synchronization signals directly from the Global Navigation Satellite System (GNSS) or the Global Positioning System (GPS).

[0089] *In this case, the sidelink synchronization source can be GNSS.

[0090] - The side-link UE can indirectly receive synchronization signals from GNSS or GPS.

[0091] *Receiving a synchronization signal indirectly from GNSS can refer to the situation where a sidelink UE-A receives a sidelink synchronization signal (SLSS) sent by a sidelink UE-1 that is directly synchronized with the GNSS. In this case, the sidelink UE-A can receive the synchronization signal from the GNSS in two hops. In another example, a sidelink UE-2 that is synchronized with a sidelink synchronization signal (SLSS) sent by a sidelink UE-1 that is also synchronized with the GNSS can send an SLSS. Once this signal is received, the sidelink UE-A can receive the synchronization signal from the GNSS in three hops. Similarly, the sidelink UE-A can receive the synchronization signal from the GNSS in more than three hops.

[0092] *In this case, the sidelink synchronization source can be another sidelink UE that is already synchronized with the GNSS.

[0093] - The sidelink UE can directly receive synchronization signals from the LTE base station (i.e., eNB).

[0094] *The sidelink UE can directly receive the primary synchronization signal (PSS) / secondary synchronization signal (SSS) sent from the eNB.

[0095] *In this case, the sidelink synchronization source can be an eNB.

[0096] - A side-link UE can indirectly receive synchronization signals from an LTE base station (i.e., an eNB).

[0097] *Receiving a synchronization signal indirectly from the eNB can refer to the situation where a sidelink UE-A receives an SLSS sent by a sidelink UE-1 that is directly synchronized with the eNB. In this case, the sidelink UE-A can receive the synchronization signal from the eNB in ​​two hops. In another example, a sidelink UE-2 that is synchronized with an SLSS sent by a sidelink UE-1 that is also synchronized with the eNB can send an SLSS. Once this signal is received, the sidelink UE-A can receive the synchronization signal from the eNB in ​​three hops. Similarly, the sidelink UE-A can receive the synchronization signal from the eNB in ​​more than three hops.

[0098] *In this case, the sidelink synchronization source can be another sidelink UE that is already synchronized with the eNB.

[0099] - The side-link UE can indirectly receive synchronization signals from the NR base station (i.e., gNB).

[0100] *Receiving a synchronization signal indirectly from the gNB can refer to the situation where a sidelink UE-A receives an SLSS sent by a sidelink UE-1 that is directly synchronized with the gNB. In this case, the sidelink UE-A can receive the synchronization signal from the gNB in ​​two hops. In another example, a sidelink UE-2 that is synchronized with an SLSS sent by a sidelink UE-1 that is also synchronized with the gNB can send an SLSS. Once this signal is received, the sidelink UE-A can receive the synchronization signal from the gNB in ​​three hops. Similarly, the sidelink UE-A can receive the synchronization signal from the gNB in ​​more than three hops.

[0101] *In this case, the sidelink synchronization source can be another sidelink UE that is already synchronized with the gNB.

[0102] - Side-link UE-A can directly receive synchronization signals from another side-link UE-B.

[0103] When sidelink UE-B fails to detect an SLSS transmitted from a GNSS, gNB, eNB, or another sidelink UE that is acting as a sidelink synchronization source, sidelink UE-B may transmit an SLSS based on its own timing. Sidelink UE-A may directly receive SLSS transmitted by sidelink UE-B.

[0104] *In this case, the sidelink synchronization source can be a sidelink UE.

[0105] - Sidelink UE-A can indirectly receive synchronization signals from another sidelink UE-B.

[0106] *Receiving a synchronization signal indirectly from a sidelink UE-B can refer to the situation where a sidelink UE-A receives an SLSS sent by a sidelink UE-1 that is directly synchronized with the sidelink UE-B. In this case, the sidelink UE-A can receive the synchronization signal from the sidelink UE-B in two hops. In another example, a sidelink UE-2 that is synchronized with an SLSS sent by a sidelink UE-1 that is also synchronized with the sidelink UE-B can send an SLSS. Once this signal is received, the sidelink UE-A can receive the synchronization signal from the sidelink UE-B in three hops. Similarly, the sidelink UE-A can receive the synchronization signal from the sidelink UE-B in more than three hops.

[0107] *In this case, the sidelink synchronization source can be another sidelink UE that has already synchronized with a sidelink UE.

[0108] In this way, the side-link UE can receive synchronization signals from the various synchronization sources mentioned above, and can perform synchronization on synchronization signals sent from synchronization sources with higher priorities according to the pre-configured priorities.

[0109] For example, the following priorities can be pre-configured, following the order from synchronization signals with higher priority to synchronization signals with lower priority.

[0110] Case A

[0111] 1) Synchronization signal sent by GNSS > 2) Synchronization signal sent by UE that performs synchronization directly from GNSS > 3) Synchronization signal sent by UE that performs synchronization indirectly from GNSS > 4) Synchronization signal sent by eNB or gNB > 5) Synchronization signal sent by UE that performs synchronization directly from eNB or gNB > 6) Synchronization signal sent by UE that performs synchronization indirectly from eNB or gNB > 7) Synchronization signal sent by UE that does not perform direct or indirect synchronization with GNSS, eNB or gNB.

[0112] Case A is an example of a synchronization signal transmitted by a GNSS with the highest priority. Alternatively, the case of a synchronization signal transmitted by an eNB or gNB with the highest priority can be considered, and the following priorities can be pre-configured.

[0113] Case B

[0114] 1) Synchronization signal sent by eNB or gNB > 2) Synchronization signal sent by UE that performs synchronization directly from eNB or gNB > 3) Synchronization signal sent by UE that performs synchronization indirectly from eNB or gNB > 4) Synchronization signal sent by GNSS > 5) Synchronization signal sent by UE that performs synchronization directly from GNSS > 6) Synchronization signal sent by UE that performs synchronization indirectly from GNSS > 7) Synchronization signal sent by UE that does not perform direct or indirect synchronization with GNSS, eNB or gNB.

[0115] Whether a sidelink UE should follow Case A priority or Case B priority can be configured by the base station or can be pre-configured. Specifically, when the sidelink UE is within the coverage area of ​​the base station (i.e., within coverage), the base station can configure whether the sidelink UE should follow Case A priority or Case B priority through system information (e.g., SIB) or RRC signaling. If the sidelink UE is outside the coverage area of ​​the base station (i.e., outside coverage), the sidelink UE should follow Case A priority or Case B priority can be pre-configured.

[0116] When the base station configures situation A to the sidelink UE via system information or RRC signaling, the base station can further configure whether the sidelink UE considers priority 4 (synchronization with synchronization signals sent by the eNB or gNB), priority 5 (synchronization with synchronization signals sent by UEs that perform synchronization directly from the eNB or gNB), and priority 6 (synchronization with synchronization signals sent by UEs that perform synchronization indirectly from the eNB or gNB) in situation A. That is, when situation A is configured and further configured to consider priorities 4, 5, and 6, all priorities in situation A (i.e., from priority 1 to priority 7) will be considered. Conversely, when situation A is configured but not configured to consider priorities 4, 5, and 6, or when situation A is configured and further configured not to consider priorities 4, 5, and 6, priorities 4, 5, and 6 will be omitted from situation A (i.e., only priorities 1, 2, 3, and 7 will be considered).

[0117] In this disclosure, the sidelink synchronization signal can refer to the sidelink synchronization signal block (S-SSB). Furthermore, the S-SSB can consist of a sidelink primary synchronization signal (S-PSS), a sidelink secondary synchronization signal (S-SSS), and a physical sidelink broadcast channel (PSBCH). The S-PSS can consist of a Zadoff-Chu sequence or an M sequence, and the S-SSS can consist of an M sequence or a gold sequence. Similar to the PSS / SSS in a cellular system, the sidelink ID can be transmitted through a combination of S-PSS and S-SSS, or solely through S-SSS. Similar to the physical broadcast channel (PBCH) in a cellular system, the PSBCH can transmit master information blocks (MIBs) for sidelink communication.

[0118] In this disclosure, the pre-configuration of sidelink parameters in the sidelink UE can primarily be applied to situations where the sidelink UE is located outside the base station's coverage area (out-of-coverage scenario). The pre-configuration of parameters in the UE can be interpreted as using default values ​​embedded in the UE during manufacturing. In other examples, this could instruct the sidelink UE to access the base station and pre-acquire and store sidelink parameter information via RRC configuration, or instruct the sidelink UE to pre-acquire and store sidelink system information from the base station, even if the sidelink UE is not accessing the base station.

[0119] Figure 5 The frame structure of a side link system according to an embodiment is shown.

[0120] Figure 5The example shown depicts a system operating with 1024 radio frames, but this is merely an example. For instance, a system could operate with fewer or more radio frames than 1024, and the number of radio frames operated by the system could be configured by the base station or pre-configured. Specifically, when the sidelink UE is within the base station's coverage area, the sidelink UE can obtain information about radio frames through the MIB of the PBCH transmitted by the base station. When the sidelink UE is outside the base station's coverage area, the information about radio frames can be pre-configured within the sidelink UE.

[0121] exist Figure 5 In this system, radio frame numbers and system frame numbers can be treated equally. That is, radio frame number '0' can correspond to system frame number '0', and radio frame number '1' can correspond to system frame number '1'. A radio frame can consist of 10 subframes, and a subframe can have a length of 1 millisecond (ms) on the time axis. For example... Figure 5 As shown, the number of time slots constituting a subframe can vary depending on the subcarrier spacing used in NR V2X. For example, when using a 15 kHz subcarrier spacing in NR V2X communication, one subframe can equal one time slot. However, when using 30 kHz and 60 kHz subcarrier spacings in NR V2X communication, one subframe can equal two and four time slots, respectively. This also applies when using subcarrier spacings of 120 kHz or greater. That is, as the subcarrier spacing based on 15 kHz increases, the number of time slots constituting a subframe can typically increase to '2n', where 'n' is 0, 1, 2, 3, etc.

[0122] Figure 6 The structure of the sidelink synchronization channel according to an embodiment is shown.

[0123] Sidelink synchronization channels can be represented by S-SSBs, and an S-SSB can consist of 14 symbols, such as... Figure 6 As shown. Furthermore, an S-SSB can consist of an S-PSS, an S-SSS, a PSBCH, and a protection period (GAP). In this case, each of the S-PSS and S-SSS can consist of two OFDM symbols, the PSBCH can consist of nine OFDM symbols, and the GAP can consist of one OFDM symbol.

[0124] like Figure 6As shown, S-PSS can be mapped to OFDM symbol indices 1 and 2, S-SSS can be mapped to OFDM symbol indices 3 and 4, and GAP can be mapped to the last OFDM symbol of S-SSB (i.e., OFDM symbol index 13). PSBCH can be mapped to the remaining OFDM symbols besides S-PSS, S-SSS, and GAP. Although Figure 6 The diagram shows that S-PSS and S-SSS are located in consecutive symbols, but they can be placed separately with a symbol inserted between them. That is, S-PSS can be mapped to OFDM symbol indices 1 and 2, S-SSS can be mapped to OFDM symbol indices 4 and 5, and PSBCH can be mapped to OFDM symbol indices 0, 3, 6, 7, 8, 9, 10, 11, and 12. A demodulation reference signal (DMRS) can be transmitted in each OFDM symbol to which the PSBCH is mapped.

[0125] Information sent via PSBCH may include at least one of the following.

[0126] 1. Frame Number: This indicates the frame number through which S-SSBs (i.e., S-PSS, S-SSS, and PSBCH) are transmitted. When the sidelink UE transmitting the S-SSB is within the coverage area of ​​the base station, the frame number can be configured based on the system frame number of the base station where the sidelink UE resides. When the sidelink UE transmitting the S-SSB is outside the coverage area of ​​the base station, the frame number can be pre-configured based on the frame number of the UE transmitting the S-SSB. The frame number can be formed using 10 bits.

[0127] 2. Downlink and Uplink Configuration Information: As shown in Figure 1B, UE-1, located within the base station's coverage area, can communicate with UE-2, located outside the base station's coverage area (i.e., partial coverage scenario). In Figure 1B, the base station where UE-1 is located can operate as a Time Division Duplex (TDD) system. In this case, sidelink signals transmitted by UE-2 and other UEs outside the base station's coverage area (although not shown in Figure 1B) may cause interference.

[0128] Specifically, when UE-1 receives control and data information from the base station via the downlink, the sidelink control and data information sent by UE-2 may interfere with the downlink signal received by UE-1. In Figure 1B, if UE-1 is located at the edge of the base station's coverage area (i.e., UE-1 is far from the base station) and UE-2 is near UE-1, the interference problem may become severe. However, when UE-1 sends control and data information to the base station via the uplink, the sidelink control and data information sent by UE-2 may interfere with the uplink signal of UE-1 received by the base station. Because UE-2 is farther from the base station than UE-1, the signal received from UE-2 at the base station's receiver will not cause much interference to the signal received from UE-1. Furthermore, because the base station can have more receiving antennas than the receiver of UE-1, it can use more advanced receiving technologies, such as interference cancellation. Therefore, when comparing the situation where UE-2's signal interferes with the receiver of UE-1 and the situation where UE-2's signal interferes with the receiver of the base station, the former situation may have a greater impact on system performance.

[0129] To address the aforementioned interference issues in TDD systems, a sidelink UE transmitting S-SSB within the base station's coverage area can send TDD configuration information set by the base station (i.e., downlink and uplink configuration information followed by all UEs within the base station's coverage area) via the PSBCH to another sidelink UE located outside the base station's coverage area. A sidelink UE located outside the base station's coverage area and receiving this information via the PSBCH can configure a resource pool for transmitting and receiving sidelink control and data information by using only uplink subframes or uplink time slots, excluding downlink subframes, special subframes, downlink time slots, and flexible time slots.

[0130] 3. Time slot index: such as Figure 5 As shown, a system frame can consist of multiple subframes. Furthermore, depending on the subcarrier spacing, a subframe can consist of multiple time slots. Therefore, it may be necessary to have an indicator indicating which time slot of the indicated frame number is used to transmit the S-SSB. The time slot index can refer to information indicating the index of the time slot through which the S-SSB is transmitted within the frame index indicated by the frame number. For example, a subcarrier spacing of 15kHz, 30kHz, 60kHz, or 120kHz can consist of 10, 20, 40, or 80 time slots within a frame formed in 10ms. Therefore, 7 bits might be needed to transmit an 80-time-slot index.

[0131] 4. Override indicator: as shown above Figure 4As described, when the base station's synchronization signal is configured to have a higher priority than the GNSS synchronization signal, an S-SSB transmitted by a sidelink UE directly synchronized with the base station can have a higher priority than an S-SSB transmitted by any other sidelink UE, i.e., a higher priority than an S-SSB transmitted by a sidelink UE directly or indirectly synchronized with GNSS and an S-SSB transmitted by another sidelink UE. This can indicate that the base station's timing is transmitted via sidelink UEs located within the base station's coverage area to sidelink UEs located outside the base station's coverage area. To determine priority, a 1-bit indicator indicating coverage status can be included in the PSBCH. For example, when the 1-bit indicator is set to '1', this can indicate that the sidelink UE transmitting the PSBCH is within the base station's coverage area. Furthermore, when the 1-bit indicator is set to '0', this can indicate that the sidelink UE transmitting the PSBCH is outside the base station's coverage area. Therefore, the sidelink UE receiving the PSBCH can determine whether the received S-SSB was sent from a sidelink UE within the base station's coverage area or from a sidelink UE outside the base station's coverage area. Based on this, it can be determined which S-SSB should be synchronized on (i.e., the sidelink synchronization source should be selected).

[0132] In addition to the information mentioned above, the PSBCH may include reserved bits that are not used in the current version. For example, it may include reserved bits consisting of 2 bits or 1 bit, which can be used in future versions of the UE. That is, the sidelink UE of version 16 does not interpret the reserved bits, and if the reserved bits are used to introduce new sidelink functions in future versions 17 and the next, then the sidelink UE after version 17 can interpret the corresponding bits.

[0133] Figure 7A illustrates a method for transmitting a sidelink synchronization signal according to a first embodiment, and Figure 7B illustrates a method for transmitting a sidelink synchronization signal according to a second embodiment.

[0134] In Figures 7A and 7B, for a UE that is a sidelink synchronization source for transmitting S-SSBs, information about the start point of S-SSB transmission can be configured from or pre-configured by the base station. Specifically, when the sidelink synchronization source is within the coverage area of ​​the base station, the base station can configure information about the start point at which the sidelink synchronization source UE can transmit S-SSBs through SIB or RRC configuration information. In this case, the information about the S-SSB transmission start point can refer to an offset, and this offset can indicate the difference between slot #0 in the system frame number (SFN) #0 of the base station where the UE transmitting S-SSBs resides and the actual start slot for transmitting S-SSBs in the period, as shown in Figures 7A and 7B.

[0135] Conversely, when the sidelink synchronization source is located outside the base station's coverage area (i.e., outside the coverage area), information about the start point for transmitting S-SSBs can be pre-configured in the UE. In this case, the information about the start point for S-SSB transmission can refer to an offset, and this offset can indicate the difference between slot #0 in the direct frame number (DFN) #0 of the UE transmitting the S-SSB and the actual start slot for transmitting the S-SSB in the period.

[0136] Figure 7A illustrates the case of configuring (or pre-configuring) one offset, and Figure 7B illustrates the case of configuring (or pre-configuring) two offsets. Configuring one or two offsets can also indicate that one or two time resources are configured for S-SSB transmission. It is possible to configure three offsets, which indicates that three time resources are configured for S-SSB transmission. When the sidelink UE is within the coverage area of ​​the base station, a maximum of one time resource can be configured for S-SSB transmission. When the sidelink UE is outside the coverage area of ​​the base station, up to three time resources can be configured (or pre-configured) for S-SSB transmission (i.e., two or three resources can be configured or pre-configured).

[0137] In Figures 7A and 7B, a subcarrier spacing (SCS) of 15 kHz is assumed. In this case, a time slot can have the same concept as a subframe. When the subcarrier spacing is defined as 15 kHz × 2n and 'n' is a positive integer (i.e., when the subcarrier spacing is greater than 15 kHz), a subframe can consist of 2n time slots. Conversely, when 'n' is a negative integer (i.e., when the subcarrier spacing is less than 15 kHz), a time slot can consist of 2n subframes. Furthermore, because a subcarrier spacing of 15 kHz is assumed in Figures 7A and 7B, a system frame (or radio frame) can consist of 10 time slots. Figure 6 As shown, a time slot can always consist of 14 OFDM symbols, regardless of the subcarrier spacing.

[0138] As described above, Figure 7A illustrates a time resource configured for S-SSB transmission. In this case, only one offset value indicating the starting point of S-SSB transmission can be configured. Specifically, as an example, the starting point for transmitting the S-SSB is shown as slot #3 of SFN#1 in Figure 7A, and this can indicate that the transmission of the S-SSB begins 13 slots after offset from slot #0 of SFN#0. Therefore, the base station can send the UE-configured offset value of 13 slots to the S-SSB via system information or RRC signaling. Using the configured offset value, a sidelink UE can transmit the S-SSB in the corresponding slot. Similarly, using a pre-configured offset value, a UE located outside the base station's coverage area can transmit the S-SSB in the corresponding slot. In this case, the S-SSB transmitted in the corresponding slot can have the structure shown in Figures 7A, 7B, or 8.

[0139] The S-SSB initially transmitted in slot #3 of SFN#1 can be repeatedly transmitted at a period of P slots, as shown in Figure 7A. The value of P can be fixed, or configured by the base station via system information or RRC signaling (or pre-configured if the sidelink UE is outside the base station's coverage area). In Figure 7A, it is assumed that the value of P is 160ms (160 subframes or 160 slots).

[0140] Figure 7B illustrates a configuration of two time resources for S-SSB transmission. In this case, two offset values ​​indicating the start point of S-SSB transmission can be configured. As mentioned above, if the sidelink UE is outside the base station's coverage area, two offset values ​​can be pre-configured. A UE pre-configured with two time resources for S-SSB transmission using these two offset values ​​can transmit S-SSBs in one of these resources and receive S-SSBs transmitted by another sidelink UE in the other resource, instead of transmitting S-SSBs in both time resources. This approach resolves the half-duplex problem where S-SSB transmission and reception cannot occur simultaneously.

[0141] As shown in Figure 7A, Figure 7B illustrates that the time resources for the first S-SSB transmission are located in slot #3 of SFN#1, 13 slots after slot #0 of SFN#0. Therefore, the value of offset1 can be 13 slots, as shown in Figure 7A. Figure 7B also shows that the time resources for the second S-SSB transmission are located in slot #8 of SFN#1, 18 slots after slot #0 of SFN#0. Therefore, the value of offset2 can be 18 slots. Thus, using the configured offset values, the sidelink UE can receive or transmit S-SSBs in the corresponding slots.

[0142] As shown in Figure 7B, the S-SSB initially transmitted in slot #3 of SFN#1 can be repeatedly transmitted with a period of P1 slots. Furthermore, the S-SSB initially transmitted in slot #8 of SFN#1 can be repeatedly transmitted with a period of P2 slots, as shown in Figure 7B. The values ​​of P1 and P2 can be fixed or pre-configured, and can be equal to or different from each other. In Figure 7B, it is assumed that each value of P1 and P2 is 160 ms (160 subframes or 160 slots).

[0143] When three time resources are configured for S-SSB transmission, three offset values ​​can be pre-configured. In this case, as with the configuration of two S-SSB transmission resources, S-SSB transmissions can be omitted from all three S-SSB transmission resources.

[0144] Figure 8 A method for transmitting a sidelink synchronization signal according to a third embodiment is shown.

[0145] Figures 7A and 7B illustrate S-SSB transmission once within an S-SSB transmission period. In contrast, it's possible for an S-SSB to be transmitted more than once within an S-SSB transmission period. For example, when transmitting S-SSBs in a hybrid beamforming system, beam scanning can be used to perform S-SSB transmission. That is, different S-SSBs can be transmitted in different beam directions. In another example, as the subcarrier spacing increases, the coverage of the S-SSB decreases due to the reduced power density. In this case, repeating the S-SSB transmission along the time axis can solve the coverage problem. Specifically, assuming S-SSBs are transmitted through M frequency blocks, the power density decreases by a factor of x when the subcarrier spacing increases by a factor of x. Therefore, the S-SSB can be repeated x times along the time axis.

[0146] For the purposes mentioned above, Figure 8 This illustrates the case where the S-SSB is transmitted four times within the S-SSB transmission cycle. Figure 8 The diagram illustrates S-SSB transmission in a time slot N0 time slots away from SFN#0 or DFN#0 (i.e., with an offset of N0). As described above, the sidelink synchronization source UE can initiate S-SSB transmission in a time slot N0 time slots away from SFN#0 or DFN#0. In this case, S-SSB can be transmitted K times during a specific time period, and this transmission can be performed in each S-SSB transmission cycle. Specifically, as... Figure 8 As shown, during time slot N2, S-SSB can be transmitted 4 times (K=4) from a time slot N0 time slots away from SFN#0 or DFN#0. Although Figure 8 It shows that N2 is different from N3, but N2 and N3 can also have the same value. Although in Figure 8 The example assumes K is 4, but this is merely an example. At least one of the values ​​of K and N2 can be configured from the base station or can be pre-configured, and may or may not change depending on the carrier band and / or SCS used for S-SSB transmission.

[0147] The value of N1 refers to the spacing between adjacent S-SSBs and can vary or remain unchanged depending on the carrier band and / or SCS used for S-SSB transmission. For example, in band 1 (or frequency range 1 (FR1)) outside the millimeter wave (mmWave) band, the value of N1 can be configured to be large because beam scanning is not required. In FR2, which includes the millimeter wave band, beam scanning may be required to extend coverage, and in this case, the value of N1 can be configured to be small to reduce the delay time in the synchronization process due to beam scanning.

[0148] In another example, S-SSB transmission can be configured in the sidelink synchronization source UE using combinations of N0, K, N2, and N3. Specifically, for S-SSB transmission, subcarrier spacing of 15kHz, 30kHz, or 60kHz can be used in FR1. Furthermore, for S-SSB transmission, subcarrier spacing of 60kHz or 120kHz can be used in FR2. The subcarrier spacing used for transmitting S-SSB in FR1 and FR2 can be related to the frequency on which the sidelink is operated, or it can be configured from the base station via system information and RRC. If there is no base station, such subcarrier spacing can use pre-configured values, or it can be configured via PC5-RRC.

[0149] In addition to the subcarrier spacing, the number of S-SSB transmissions (K) in each subcarrier spacing can be configured from the base station via system information and RRC. If there is no base station, the number of S-SSB transmissions can use a pre-configured value or can be configured via PC5-RRC. For example, when using a 15kHz subcarrier spacing in FR1, K can be 1. When using a 30kHz subcarrier spacing in FR1, K can be 1 or 2. When K is set to 2, the S-SSB can be transmitted twice. When using a 60kHz subcarrier spacing in FR1, K can be 1, 2, or 4. When K is set to 2 or 4, the S-SSB can be transmitted twice or four times. When using a 60kHz subcarrier spacing in FR2, K can be set to one of 1, 2, 4, 8, 16, and 32. As in the examples above, a K greater than 1 indicates the corresponding number of times the S-SSB is transmitted. When using a 120kHz subcarrier spacing in FR2, K can be set to one of 1, 2, 4, 8, 16, 32, and 64. In the example above, a K greater than 1 can indicate the number of times the S-SSB is repeatedly sent.

[0150] N3 can always be fixed at 160ms. Furthermore, the value of N1 can be configured from the base station via system information and RRC. If there is no base station, the value of N1 can use a pre-configured value, or it can be configured via PC5-RRC.

[0151] exist Figure 8 In this context, the same or different beams can be used to transmit S-SSBs. For example, in... Figure 8 In this context, time slots #a0, #a1, #a2, #a3, #b0, #b1, #b2, and #b3 are the locations for transmitting S-SSBs. In this case, in... Figure 8 The S-SSBs transmitted in time slots #a0, #a1, #a2, and #a3 can use different beams, which can be repeatedly transmitted in time slots #b0, #b1, #b2, and #b3 (i.e., the beam from time slot #a0 is transmitted in time slot #b0, and the beam from time slot #a1 is transmitted in time slot #b1). In another example, in Figure 8 S-SSBs transmitted in time slots #a0, #a1, #a2, and #a3 can use the same beam, and beams different from those transmitted in time slots #a0, #a1, #a2, and #a3 can be used for S-SSB transmission in time slots #b0, #b1, #b2, and #b3.

[0152] Figure 9 An uplink-downlink configuration in base station coverage according to an embodiment is shown.

[0153] In a 5G communication system, the UL / DL configuration of time slot 901 and symbol 902 can be performed in three steps. First, the UL / DL of the symbol / time slot can be semi-statically configured in the symbol unit based on cell-specific configuration information 910 through system information. Specifically, the cell-specific UL / DL configuration information through system information can include UL / DL pattern information and reference subcarrier information. Through the UL / DL pattern information, the mode period 903, the number of consecutive DL time slots 911 starting from the start point of each mode, the number of symbols in the next time slot 912, the number of consecutive UL time slots 913 starting from the end of the mode, and the number of symbols in the next time slot 914 can be indicated. In this case, the UE can determine time slots and symbols not indicated by UL and DL as flexible time slots / symbols.

[0154] Second, based on user-specific configuration information 920 via dedicated high-level signaling, in each of the time slots 921 and 922 containing flexible time slots or symbols, the number of consecutive DL symbols 923 or 925 can be indicated from the start symbol of the time slot, and the number of consecutive UL symbols 924 or 926 can be indicated from the end of the time slot, or the entire time slot can be indicated as DL or UL.

[0155] Finally, in order to dynamically change the DL / UL signal transmission segments, each symbol in each time slot that is indicated as a flexible symbol (i.e., a symbol not indicated as DL or UL) can be indicated by the slot format indicator (SFI) 931 or 932 contained in the DL control channel as a DL symbol, UL symbol, or flexible symbol.

[0156] Figure 10 The number of uplink-downlink symbols occupied by 14 symbols constituting a time slot is shown according to an embodiment.

[0157] when Figure 9 The time slot format indicator shown indicates Figure 10 When selecting an index in the format shown, you can choose the format for a specific time slot.

[0158] Figure 11 This illustrates when information is sent and received between sidelink terminals according to an embodiment.

[0159] exist Figure 11 In this example, side-link UE 1102 exists within the coverage area communicating with base station 1100, while another side-link UE 1104 exists outside the coverage area communicating with base station 1100. For example... Figure 11 As shown, side-link UEs 1102 and 1104 can be synchronized with the signal of GNSS 1106, or side-link UE 1104 can be synchronized by a synchronization signal sent by a terminal other than GNSS 1106. (See Figure 1B.) Figure 11 The link between UE 1102 and base station 1100 can be a Uu link consisting of an uplink and a downlink, and the link between UE 1102 and 1104 can be a side link. UE 1104 can perform a side link synchronization procedure to send and receive control / data information with other UEs, including UE 1102. If UE 1102 sends a synchronization signal, in addition to the side link synchronization signal, UE 1102 can also send broadcast information including basic information about the side link. Side link broadcast information can be sent from UE 1102 to UE 1104 via PSBCH.

[0160] Sidelink broadcast information can be referred to by other terms, such as sidelink MIB (SL-MIB) or sidelink system information. Figure 6 As described, the sidelink broadcast information may contain a field indicating the time resource region for S-SSB transmission. This field may be referred to as a term such as TDD-SL-config, TDD-SL-configCommon, or common sidelink resource information. When configuring S-SSB time resource information, the TDD information configured for Uu communication between base station 1100 and UE 1102 (i.e., the TDD information configured for cellular communication, not the TDD information configured for sidelink communication) should be considered. For example, when UE 1104 performs a sidelink transmission during the downlink receive cycle of UE 1102, the downlink receive performance of UE 1102 may be degraded due to interference from UE 1104. In contrast, when UE 1104 performs a sidelink transmission during the uplink transmit cycle of UE 1102 (i.e., the receive cycle of base station 1100), the sidelink signal of UE 1104 received by base station 1100 may interfere with the uplink signal of UE 1102. However, because UE 1104 is farther from base station 1100 than UE 1102, the interference caused by the sidelink signal of UE 1104 to the uplink signal of UE 1102 at the receiving end of base station 1100 is likely to be minimal. Therefore, performing sidelink transmission / reception at least within the resource area configured for uplink transmission period Uu can minimize the interference caused by the sidelink to the cellular link. The TDD configuration information for the sidelink may include at least one of the following.

[0161] Reference subcarrier spacing

[0162] - Pattern 1 (transmission period, number of downlink slots, number of downlink symbols, number of uplink slots, number of uplink symbols)

[0163] - Pattern 2 (transmission period, number of downlink time slots, number of downlink symbols, number of uplink time slots, number of uplink symbols)

[0164] Depending on the base station's configuration or pre-configuration, mode 2 can be omitted. For example... Figure 9As shown, a mode has a specific transmission cycle, and the downlink, uplink, or flexible symbol in the corresponding transmission cycle can be determined based on the number of downlink time slots, the number of downlink symbols, the number of uplink time slots, and the number of uplink symbols. Specifically, the number of downlink time slots in the transmission cycle can refer to the number of time slots consisting only of downlink symbols, and the number of downlink symbols can refer to the number of downlink symbols configured starting from the first symbol in the time slot immediately following the number of time slots consisting only of downlink symbols. Furthermore, the number of uplink time slots in the transmission cycle can refer to the number of time slots consisting only of uplink symbols, and the number of uplink symbols can refer to the number of uplink symbols configured starting from the last symbol in the time slot immediately preceding the number of time slots consisting only of uplink symbols. Additionally, symbols or time slots not configured as downlink or uplink in the transmission cycle can be considered flexible symbols or flexible time slots by the UE. In the areas corresponding to flexible symbols and flexible time slots, uplink or downlink control and data information can be transmitted and received via another upper-layer signal or L1 signal. The information required to configure TDD information for Uu may include reference subcarrier spacing information and information for modes 1 and 2. Information for modes 1 and 2 may require information about the transmission period, the number of uplink / downlink time slots, and the number of uplink / downlink symbols. In this case, information about the transmission period may require 3 bits, information about the number of uplink or downlink time slots may require 9 bits, and information about the number of uplink or downlink symbols may require 4 bits. In Uu, TDD information can be transmitted and received as SIB information in the form of Physical Downlink Shared Channel (PDSCH).

[0165] Considering the TDD information configured in the Uu link, common-side link resource information needs to be configured, and since it is sent / received via PSBCH, high transmission reliability is required for this common-side link resource information. Therefore, fewer bits are needed than those used to configure the TDD information in the Uu link.

[0166] Public sidelink resource information can be configured with specific fields using at least one of the following methods. Furthermore, it is entirely possible to configure public sidelink resource information using any combination of the following methods.

[0167] Method 11-1The field includes 2 bits for the reference subcarrier spacing, 3 bits for the transmission period, and 7 bits for the number of sidelink time slots, for a total of 12 bits. The reference subcarrier spacing is used as a reference for configuring sidelink resources, and candidate values ​​can be 15, 30, 60, and 120 kHz. The transmission period refers to the period during which the sidelink resource configuration is repeated, and can be expressed as one of 0.5, 0.625, 1, 1.25, 2, 2.5, 5, and 10 ms. In this case, the 0.625 ms value is only valid when the reference subcarrier spacing is 120 kHz, the 1.25 ms value is only valid when the reference subcarrier spacing is 60 or 120 kHz, and the 2.5 ms value is only valid when the reference subcarrier spacing is 30, 60, or 120 kHz.

[0168] Alternatively, the available value for the transmission period can vary depending on the reference subcarrier spacing. For example, Table 1 below shows the values ​​indicated by the transmission period field based on the reference subcarrier spacing.

[0169] Table 1

[0170]

[0171] In Table 1, the number of sidelink slots refers to the number of slots configured for the sidelink out of all slots within the indicated transmission period, and the sidelink slots are sequentially located starting from the last slot in the transmission period (in reverse order). The number of sidelink slots, formed by 7 bits, can indicate a maximum of 128 slots. Alternatively, the last 2*n or 3*n (or a natural number * n) slots in the transmission period can be indicated for the sidelink. In this case, 'n' is the slot value for the sidelink indicated by the aforementioned 7 bits, and the value of the natural number multiplied by 'n' can vary depending on the subcarrier spacing. For example, when the number of sidelink slots is 10 and the total number of slots in the transmission period is 100, the UE determines that the last 10 slots out of the 100 slots are configured for the sidelink. The UE does not expect the value indicated by the number of sidelink slots, formed by 7 bits, to be configured to indicate more than the total number of slots determined by the reference subcarrier spacing and the transmission period, and if this occurs, the UE considers it an error. Furthermore, the number of side link slots formed by 7 bits can be configured from the least significant bit (LSB). Method 11-1 is characterized by having information only about the number of slots for a specific link (e.g., a side link), in addition to the reference subcarrier spacing and transmission period, so as to have a TDD information size smaller than Uu as described above.

[0172] Method 11-2While similar to method 11-1, this method notifies the common sidelink resource information when the base station operates modes 1 and 2 in Uu. When notifying TDD information in Uu, the base station configures the transmission periods of modes 1 and 2 to have the same value. Therefore, this transmission period value can be configured as the transmission period of the common sidelink resource information. For example, if each transmission period of mode 1 and mode 2 is 10ms, then the transmission period of the common sidelink resource information is also set to 10ms. This can be considered as PS = P1 = P2, where PS is the sidelink transmission period, P1 is the transmission period of mode 1, and P2 is the transmission period of mode 2. Furthermore, the minimum value among the number of uplink slots for each mode included in the TDD information in Uu can be used as the value of the number of sidelink slots in the common sidelink resource information. For example, when the number of uplink slots for mode 1 is 10 and the number of uplink slots for mode 2 is 5, the number of sidelink slots in the common sidelink resource information is set to 5. This can be considered as NS = min(N1, N2), where NS is the number of sidelink time slots, N1 is the number of uplink time slots in mode 1, and N2 is the number of uplink time slots in mode 2.

[0173] Method 11-3 Although similar to Method 11-1, the information indicated by the 3-bit transmission period in the common-side link resource information is different in Method 11-3. Eight values ​​other than two of the ten values ​​of 0.5, 0.625, 1, 1.25, 2, 2.5, 4, 5, 10, and 20 ms can be configured as the 3-bit transmission period. For example, values ​​of 0.5, 1, 2, 2.5, 4, 5, 10, and 20 ms, excluding 0.625 and 1.25, can be used to indicate the transmission period information in the common-side link resource information.

[0174] Method 11-4 While similar to Method 11-1, Method 11-4 includes 2 bits of reference subcarrier spacing, 4 bits of transmission period, and 6 bits of the number of sidelink time slots, for a total of 12 bits. The reference subcarrier spacing is used as a reference for configuring sidelink resources, and candidate values ​​can be 15, 30, 60, and 120 kHz. The transmission period refers to the time during which the sidelink resource configuration is repeated and has a value of 0.5, 0.625, 1, 1.25, 2, 2.5, 4, 5, 10, and 20 ms. In this case, the 0.625 ms value is only valid when the reference subcarrier spacing is 120 kHz, the 1.25 ms value is only valid when the reference subcarrier spacing is 60 or 120 kHz, and the 2.5 ms value is only valid when the reference subcarrier spacing is 30, 60, or 120 kHz.

[0175] The number of sidelink slots refers to the number of slots configured for sidelinks out of all slots within the indicated transmission period, and the sidelink slots are sequentially positioned (in reverse order) starting from the last slot in the transmission period. The number of sidelink slots, formed by 6 bits, can indicate a maximum of 64 slots. Alternatively, the last 2*n or 3*n (or a natural number * n) slots in the transmission period can be indicated for sidelinks. In this case, 'n' is the slot value for the sidelinks indicated by the aforementioned 6 bits, and the value of the natural number multiplied by 'n' can vary depending on the subcarrier spacing. For example, in a reference subcarrier spacing of 120 kHz, the last 2n slots in the transmission period can be indicated for sidelinks, in which case a maximum of 128 slots can be indicated as the number of sidelink slots. The UE does not expect the value indicated by the number of sidelink slots formed by 6 bits to be configured to indicate more than the total number of slots determined by the reference subcarrier spacing and the transmission period. If this occurs, the UE considers it an error. Furthermore, the number of sidelink slots formed by 6 bits can be configured from the LSB.

[0176] Method 11-5 While similar to Method 11-1 in that the common sidelink resource information includes fields such as the reference subcarrier spacing, transmission period, and number of sidelink slots, in Method 11-5, the number of transmission periods and sidelink slots can vary in bit count depending on the 2-bit reference subcarrier spacing. For example, in a reference subcarrier spacing of 15 kHz or 30 kHz, the number of transmission periods and sidelink slots can be formed by 3 bits and 7 bits, respectively, and in a reference subcarrier spacing of 60 kHz or 120 kHz, the number of transmission periods and sidelink slots can be formed by 4 bits and 6 bits, respectively. Furthermore, even if the transmission period has the same number of bits, the value of the transmission period indicated for each reference subcarrier spacing can be different. For example, Table 2 below shows the values ​​indicated by the transmission period field based on the reference subcarrier spacing.

[0177] Table 2

[0178]

[0179]

[0180] In Table 2, if the reference subcarrier spacing is 15kHz or 30kHz, the values ​​indicated by the 3-bit transmission period can be 0.5, 1, 2, 2.5, 4, 5, 10, and 20, where 2.5 can be considered a valid indication only for 30kHz. Additionally, if the reference subcarrier spacing is 60kHz or 120kHz, the values ​​indicated by the 4-bit transmission period can be 0.5, 0.625, 1, 1.25, 2, 2.5, 4, 5, 10, and 20, where 0.625 can be considered a valid instruction only for 120kHz. The number of sidelink slots (x*n) indicates that the last x*n slots in the transmission period will be configured for the sidelink. In this case, 'x' is a natural number and can have different values ​​for each subcarrier spacing, or the same value regardless of the subcarrier spacing, and 'n' is the value indicated by the field "Number of Sidelink Slots" in the common sidelink resource information.

[0181] Method 11-6 While similar to methods 11-1 or 11-5 in that the common sidelink resource information includes fields such as the reference subcarrier spacing, transmission period, and number of sidelink slots, in method 11-6, the number of sidelink slots can vary in bit count depending on the 2-bit reference subcarrier spacing, while the transmission period remains at 4 bits. For example, in a reference subcarrier spacing of 15 kHz or 30 kHz, a number of sidelink slots formed by 6 bits and reserved bit information formed by 2 bits can be used, and in a reference subcarrier spacing of 60 kHz or 120 kHz, a number of sidelink slots formed by 7 bits and reserved bit information formed by 1 bit can be used. Reserved bits are not fields included in the common sidelink resource information. However, reserved bits can be configured as one of the information fields in the PSBCH through which the common sidelink resource information is transmitted and received, and can be used for future services.

[0182] Method 11-7 This is a generalization of methods 11-1 to 11-6 described above. The common sidelink information has a k-bit value and is configured with fields including x bits of the reference subcarrier spacing, y bits of the transmission period, and z bits of the number of sidelink time slots (i.e., k = x + y + z). Depending on the reference subcarrier spacing value, at least one of 'y' and 'z' can have different values. Consider the transmission period (T) available in a specific subcarrier spacing (i). i The value of 'y' is determined by the quantity of 'y', and can be determined by y i =ceiling(log2(T) i To determine.

[0183] The 'y' included in the common sidelink information can have a different bit value for each reference subcarrier interval, or it can be calculated using some or all subcarrier interval values. i The maximum value among the values ​​(i.e., max(y1, y2, ..., y)). i Considering the maximum number of sidelink slots available in a given subcarrier interval (i) (N) i The value of 'z' can be determined by z. i =ceiling(log2(N) i To determine.

[0184] The 'z' included in the common sidelink information can have a different bit value for each reference subcarrier interval, or it can be a z calculated using some or all subcarrier interval values. i The maximum value among the values ​​(i.e., max(z1, z2, ... z)). i The number of side link time slots (N) indicated by the z-bit value. i ) can be indicated as N i = m * b, where 'm' is a natural number that can vary depending on the subcarrier spacing, or may remain unchanged, and 'b' is the value indicated by the z-bit. The number of sidelink time slots refers to the number of the last time slots configured for the sidelink within the time slots of the transmission cycle.

[0185] Method 11-8 This is similar to the methods described above in that the common sidelink information has a k-bit value and is configured with fields including x-bit reference subcarrier spacing, y-bit transmission period, and z-bit number of sidelink slots. However, in methods 11-8, the z-bit consists of za-bits and zb-bits (i.e., z = za + zb). The value of 'za' indicates the granularity information of the slots used for the sidelink, and the value of 'zb' indicates the number of sidelink slots. In other words, the number of sidelink slots (N) i ) was determined to be N i = m*b, where the values ​​of 'm' and 'b' can be determined by the za bits and zb bits, respectively.

[0186] For example, when the reference subcarrier spacing is 120 kHz and the transmission period is 20 ms, there may be a total of 160 time slots within the indicated transmission period, and when indicating sidelink time slots in units of one time slot, a total of 8 bits may be required. However, if less than 8 bits are needed due to the limitation of PSBCH information size, and if sidelinks can be indicated in units of 4 time slots, a total of 6 bits may be required, since only a total of 40 time slots need to be indicated. For each subcarrier spacing, the bit size of "za" and "zb" may or may not change, and the range of information indicated by each bit may or may not change for each subcarrier spacing. Alternatively, unlike methods 11-8, a method using a single field to inform about the transmission period and the number of sidelink time slots can be fully considered. That is, in this method, a value of a specific field can indicate the transmission period and the number of the last time slots used for sidelink communication within the transmission period.

[0187] Figure 12 The link types through which a sidelink terminal can perform sidelink communication according to an embodiment are shown.

[0188] Specifically, sidelink communication can be performed through at least one of the following links.

[0189] A link between an NR sidelink UE and another NR sidelink UE can be referred to as an NR sidelink. An NR sidelink UE can send sidelink control information and data information for NR sidelink communication to another NR sidelink UE via the NR sidelink. Furthermore, an NR sidelink UE can receive sidelink control information and data information for NR sidelink communication from another NR sidelink UE via the NR sidelink.

[0190] The link between the NR sidelink UE and the LTE sidelink UE can be referred to as the LTE sidelink. In this case, it can be assumed that the NR sidelink UE has the capability to support LTE sidelink communication. The NR sidelink UE can send and receive control information and data information for LTE sidelink communication through the LTE sidelink.

[0191] - The downlink or uplink between the NR side link UE and the NR base station can be referred to as NR Uu.

[0192] *The NR sidelink UE can receive control and data information about NR sidelink transmission and reception from the gNB via NR Uu. Furthermore, the NR sidelink UE can transmit NR sidelink control and data information received from another NR sidelink UE to the gNB via NR Uu.

[0193] *The NR sidelink UE can receive control and data information regarding LTE sidelink transmission and reception from the gNB via the NR Uu. Furthermore, the NR sidelink UE can transmit LTE sidelink control and data information received from the LTE sidelink terminal to the gNB via the NR Uu. In this case, it can be assumed that the NR sidelink UE has the capability to support LTE sidelink communication.

[0194] The downlink or uplink between the NR side link UE and the LTE base station (eNB) can be referred to as LTE Uu.

[0195] *The NR sidelink UE can receive control and data information regarding NR sidelink transmission and reception from the eNB via LTE Uu. Furthermore, the NR sidelink UE can transmit NR sidelink control and data information received from another NR sidelink UE to the eNB via LTE Uu. In this case, it can be assumed that the NR sidelink UE has the capability to support LTE Uu.

[0196] - The NR sidelink UE can receive control and data information regarding LTE sidelink transmission and reception from the eNB via LTE Uu. Furthermore, the NR sidelink UE can transmit LTE sidelink control and data information received from the LTE sidelink terminal to the eNB via LTE Uu. In this case, it can be assumed that the NR sidelink UE has the capability to support LTE sidelink communication and also has the capability to support LTE Uu.

[0197] Figure 13 The side link synchronization process according to the first embodiment is illustrated.

[0198] exist Figure 13 In this scenario, NR V2X UE-1 and LTE V2X UE-1 are within the eNB's coverage area, while NR V2X UE-2 and LTE V2X UE-2 are outside the eNB's coverage area. NR V2X UE-1 and LTE V2X UE-1, within the eNB's coverage area, can detect and receive LTE PSS / SSS transmitted by the eNB; however, NRV2X UE-2 and LTE V2X UE-2, outside the eNB's coverage area, cannot detect and receive LTE PSS / SSS transmitted by the eNB. Figure 13 In this context, it can be assumed that NR V2X UE-1 within the eNB coverage area has already been based on Figure 4 The rules described in [the document] select the eNB as the synchronization source. Although Figure 13The example shown illustrates that the NR V2X UE-1 can transmit both NR S-SSB and LTE SLSS, but this is merely an example. That is, the NR V2X UE-1 can have the capability to transmit only NR S-SSB without the ability to transmit LTE SLSS.

[0199] Since the NR V2X UE-1 within the eNB's coverage area has selected the eNB as its synchronization source, this indicates that the NR V2X UE has the capability to detect LTE PSS / SSS signals as synchronization signals from the eNB (Alt1). In a further example, the NR V2X UE-1's selection of the eNB as its synchronization source can indicate that the NR V2X UE-1 can detect LTE PSS / SSS signals transmitted by the eNB and decode the LTE PBCH (Alt2), detect LTE PSS / SSS signals transmitted by the eNB, decode the LTE PBCH, and also decode the LTE V2X SIB information configured for the LTE V2X UE (Alt3), or detect LTE PSS / SSS signals transmitted by the eNB, decode the LTE PBCH, and decode the NR V2X SIB information configured for the NR V2X UE within the eNB's coverage area (Alt4). Alternatively, the UE can support both Alt3 and Alt4.

[0200] Under these different assumptions, an NR V2X UE within the eNB coverage area can send NR S-SSBs for a sidelink UE located outside the eNB coverage area. In this case, Figures 6 to 11 The above information can be included in the PSBCH used to construct the NRS-SSB. Specifically, it can include... Figure 6 At least one of the frame number, downlink and uplink configuration information, slot index, and coverage indicator described in the document. Additionally, it can be obtained through... Figure 11 One of the methods described in the document is used to configure downlink and uplink configuration information.

[0201] exist Figure 13In one example, NR V2X UE-1 can configure the PSBCH coverage indicator field to '1' because it is within the eNB's coverage area. In another example, because NR V2X UE-1 is within the eNB's coverage area but transmits NR S-SSB, from the perspective of the NR sidelink, NR V2X UE-1 can be considered outside the base station's coverage area. Therefore, in this case, NR V2X UE-1 can configure the PSBCH coverage indicator field to '0'. Specifically, if the eNB's Uu and the NR V2X UE-1's NR sidelink have the same frequency, NR V2X UE-1 is considered within the base station's coverage area, and the PSBCH coverage indicator field can be set to '1'. Conversely, if the eNB's Uu and the NR V2X UE-1's NR sidelink have different frequencies, NR V2X UE-1 is considered outside the base station's coverage area, and the PSBCH coverage indicator field can be set to '0'.

[0202] exist Figure 13 In this context, the NR S-SSB sent by NR V2X UE-1 within the eNB coverage area is used to perform sidelink synchronization operations for NR sidelink UEs located outside the eNB coverage area. For example... Figure 4 As described, the NR sidelink UE can select either the NR base station (gNB) or the LTE base station (eNB) as its sidelink synchronization source. Because the NR V2X UE-1 is within the gNB coverage area, it can... Figure 6 The described method of transmitting uplink-downlink configuration information via PSBCH aims to minimize interference caused by sidelink UEs located outside gNB coverage to cellular UEs or sidelink UEs within gNB coverage. However, when the carrier frequency of Uu operation and the frequency of NR sidelink operation are different, it may not be necessary to consider the aforementioned interference issue. In this case, the uplink-downlink configuration information included in the PSBCH is unnecessary and can be omitted, set to unused (i.e., none), or set to specific values ​​(e.g., all bits indicating uplink-downlink configuration information are set to '0' or '1'). Conversely, when the carrier frequency of Uu operation and the frequency of NR sidelink operation are equal, it is necessary to consider the interference issue.

[0203] In this case, such as Figure 6 As shown, uplink-downlink configuration information, consisting of 12 or 13 bits, can be included in the PSBCH.

[0204] Figure 14 The side link synchronization process according to the second embodiment is illustrated.

[0205] exist Figure 14 In this scenario, NR V2X UE-1 and NR V2X UE-2 are within the gNB's coverage area, while NR V2X UE and LTE V2X UE are outside the gNB's coverage area. NR V2X UE-1 and NR V2X UE-2, within the gNB's coverage area, can detect and receive NR SSBs transmitted by the gNB. However, NR V2X UE and LTE V2X UE, outside the gNB's coverage area, cannot detect and receive NR SSBs transmitted by the gNB. Furthermore, the LTE V2X UE cannot detect and receive NR SSBs, even if it is within the gNB's coverage area. Figure 14 In this context, it can be assumed that NR V2X UE-1 and NR V2X UE-2 within the gNB coverage area have already been based on Figure 4 The rules mentioned above selected gNB as the synchronization source. Although Figure 14 The example shown illustrates that the NR V2X UE-1 can transmit both NR S-SSB and LTE SLSS, but this is merely an example. That is, the NR V2X UE-1 can have the capability to transmit only NR S-SSB without the ability to transmit LTE SLSS.

[0206] exist Figure 13 The diagram shows an NR sidelink UE present within eNB coverage and expecting to transmit NRS-SSB within gNB coverage. Conversely, Figure 14 This illustrates a scenario where an NR sidelink UE exists within gNB coverage and intends to transmit LTE SLSS within that coverage area. The subcarrier spacing used for LTE SLSS transmission is always fixed at 15kHz, which may differ from the subcarrier spacing used for NRS-SSB transmission. Therefore, when NR V2X UE-1 transmits LTE SLSS within gNB coverage, and when NR Uu and the LTE sidelink operate on the same carrier frequency, this can potentially cause interference to both the UE performing NR sidelink communication and the UE performing NR cellular communication within gNB coverage. Conversely, if NR Uu and the LTE sidelink operate on different carrier frequencies, the aforementioned interference issue may not be a concern.

[0207] Under these different assumptions, an NR sidelink UE (supporting LTE sidelink) within the gNB coverage area can transmit LTE SLSS for an LTE sidelink UE located outside the gNB coverage area. In this case, Figure 6 The information mentioned above can be included in the PSBCH used to construct the LTE SLSS. Specifically, it can include... Figure 6The frame number, downlink and uplink configuration information, slot index, and coverage indicator described in the document are used. In this case, because LTE SLSS only uses a 15kHz subcarrier spacing, the slot index can have the same characteristics as described in the document. Figure 6 The subframe index described in the text has the same meaning.

[0208] exist Figure 14 In one example, NR V2X UE-1 can configure the PSBCH coverage indicator field to '1' because it is within the gNB coverage area. In another example, because NR V2X UE-1 is within the gNB coverage area but transmits LTE SLSS, from the perspective of the LTE sidelink, NR V2X UE-1 can be considered outside the base station's coverage area. Therefore, NR V2X UE-1 can configure the PSBCH coverage indicator field to '0'. Specifically, if the gNB's Uu and NR V2X UE-1's LTE sidelink have the same frequency, NR V2X UE-1 is considered within the base station's coverage area, and the PSBCH coverage indicator field can be set to '1'. Conversely, if the gNB's Uu and NR V2X UE-1's LTE sidelink have different frequencies, NR V2X UE-1 is considered outside the base station's coverage area, and the PSBCH coverage indicator field can be set to '0'.

[0209] exist Figure 13 In this context, the NR S-SSB sent by NR V2X UE-1 within the eNB coverage area is used to perform sidelink synchronization operations for NR sidelink UEs located outside the eNB coverage area. For example... Figure 4 As shown, the NR sidelink UE can select either the NR base station (gNB) or the LTE base station (eNB) as the sidelink synchronization source. However, in Figure 14 In this context, the LTE SLSS transmitted by NR V2X UE-1 within the gNB coverage area is used to perform sidelink synchronization operations for LTE sidelink UEs located outside the gNB coverage area. Because LTE sidelink UEs cannot select the gNB as their sidelink synchronization source, NR V2X UE-1 can always set the PSBCH coverage indicator to [value missing]. Figure 14 The '0' in the Uu operation is used regardless of whether the carrier frequency of the Uu operation is equal to or different from the carrier frequency of the LTE sidelink operation.

[0210] Because NR V2X UE-1 is within the gNB coverage area, it can be like Figure 6The diagram shows uplink-downlink configuration information transmitted via the PSBCH to minimize interference caused by sidelink UEs located outside the gNB coverage area to cellular UEs or sidelink UEs located within the gNB coverage area. However, when the carrier frequency of NR Uu operation and the frequency of LTE sidelink operation are different from each other, the aforementioned interference issue does not need to be considered. In this case, the uplink-downlink configuration information included in the PSBCH is unnecessary and can be omitted, set to unused (i.e., none), or set to specific values ​​(e.g., all bits indicating uplink-downlink configuration information are set to '0' or '1'). Conversely, when the carrier frequency of NR Uu operation and the frequency of LTE sidelink operation are equal to each other, it is necessary to consider the interference issue.

[0211] The LTE sidelink operates in a dedicated frequency band for the Intelligent Transport System (ITS), which may differ from the NR Uu band. Furthermore, the PSBCH transmitted by NR V2X UE-1 within the gNB coverage area is used to support the synchronization process of the LTE sidelink UE. As mentioned above, because the LTE sidelink UE does not consider the gNB as a sidelink synchronization source, therefore... Figure 14 Even if the NR V2X UE-1 is within the base station's coverage area, the NR V2X UE-1 can set the coverage indicator to "0", and the uplink-downlink configuration information formed by 3 bits can be included in the PSBCH, just like in the PSBCH of a traditional LTE sidelink. In this case, the uplink-downlink configuration information included in the PSBCH sent by the NR V2X UE-1 can be set to "none".

[0212] Figure 15 The structure of a terminal according to an embodiment is shown.

[0213] refer to Figure 15 The terminal (UE) may include a transceiver, a terminal controller, and a memory. In this disclosure, the terminal controller may be defined as a circuit, an application-specific integrated circuit, or at least one processor.

[0214] A transceiver can send signals to and receive signals from other network entities. For example, a transceiver can receive system information from a base station and can receive synchronization signals or reference signals.

[0215] According to an embodiment, the terminal controller can control the overall operation of the terminal. For example, the terminal controller can control the signal flow of operations described in this disclosure and shown in the accompanying drawings. Specifically, the terminal controller operates according to control signals received from the base station and can exchange messages or signals with other terminals and / or base stations via a transceiver.

[0216] The memory can store at least one of the information sent and received by the transceiver and the information generated by the terminal controller.

[0217] Figure 16 The structure of a base station according to an embodiment is shown.

[0218] refer to Figure 16 A base station (eNB or gNB) may include a transceiver, a base station controller, and a memory. In this disclosure, the base station controller may be defined as a circuit, an application-specific integrated circuit, or at least one processor.

[0219] A transceiver can send signals to and receive signals from other network entities. For example, a transceiver can send system information to a terminal and can send synchronization signals or reference signals.

[0220] According to embodiments, the base station controller can control the overall operation of the base station. For example, the base station controller can control the operations described in this disclosure to manage and reduce interference with neighboring base stations. Specifically, the base station controller sends control signals to the terminal via a transceiver to control the terminal's operation, and can exchange messages or signals with the terminal via the transceiver.

[0221] The memory can store at least one of the information transmitted and received by the transceiver and the information generated by the base station controller.

[0222] Figure 17 The illustration shows sidelink resource information received by a sidelink terminal according to an embodiment.

[0223] refer to Figure 17 and Figure 11 The sidelink UE 1104 receives sidelink resource information from the sidelink UE 1102 via the PSBCH. Specifically, the sidelink resource information may include TDD configuration information for uplink and downlink communication within the coverage area of ​​the base station 1100. The TDD configuration information may indicate at least one or any combination of the following fields.

[0224] 1. Field indicating transmission period: This field indicates the period of resources (e.g., uplink time slots) used for uplink transmissions of UEs located within the coverage area of ​​base station 1100 operating in TDD mode. This field may include all values ​​of 0.5, 0.625, 1, 1.25, 2, 2.5, 4, 5, 10, and 20 ms, or at least some of these values. In addition to the values ​​mentioned above, integer values ​​that can be divided by 20 ms without a remainder may be included, and the minimum such integer value may be 0.5 ms. Furthermore, the values ​​indicating the above transmission period may vary depending on the subcarrier spacing. For example, when configuring the transmission period based on a 15 kHz subcarrier spacing, the transmitting UE is allowed to use 3 bits to fully inform which value among 0.5, 1, 2, 4, 5, 10, and 20 ms is configured as the transmission period. Regardless of the S-SSB subcarrier spacing, a 15 kHz subcarrier spacing can always be applied as a fixed value. Furthermore, 15 kHz is an example; any other subcarrier spacing can always be applied as a fixed value. Furthermore, FR1 and FR2 can have different fixed subcarrier spacing values. The transmission period can be considered as the value of 'T'.

[0225] 2. Field indicating transmission period mode: This field may or may not appear in the PSBCH, depending on the subcarrier spacing. When present in the PSBCH, it can contain 1 bit of information. This indicates whether the transmission period value configured in the transmission period field has one transmission period or a combination of two transmission periods of equal length.

[0226] For example, when the transmission period value indicates 10ms in the transmission period field, a 1-bit transmission period mode field can indicate whether the transmission period value indicates a 10ms transmission period or the sum of two 5ms transmission periods. Alternatively, it can indicate whether the transmission period value configured in the transmission period field indicates one transmission period or one of two consecutive transmission periods. For example, when the transmission period value indicates 10ms in the transmission period field, a 1-bit transmission period mode field can indicate whether the transmission period value indicates one 10ms transmission period or another 20ms transmission period formed by two 10ms units. In short, the transmission period mode field can be used to indicate whether the transmission period value represents one transmission period or a combination of two transmission periods. If the transmission period value indicated in the transmission period field is T, the former case refers to T = T1 + T2, where T1 = T2, and the latter case refers to T + T = T0.

[0227] 3. Field indicating the number of sidelink time slots: This field indicates information about the number of time slots used for sidelink communication within a transmission period configured by the transmission period field and the transmission period mode field. Specifically, this field indicates the number of sidelink time slots starting from the last time slot among all time slots included in the transmission period indicated by the transmission period field and the transmission period mode field (in reverse order).

[0228] For example, if a total of 100 time slots are determined by the transmission period field and the transmission period pattern field, and if 10 time slots are determined by the number of sidelink time slots field, then the UE determines that the last 10 time slots out of the 100 time slots are used for sidelink communication. Furthermore, the method for interpreting the number of sidelink time slots field can vary depending on the transmission period pattern. For example, if the transmission period pattern field indicates a combination of two transmission periods, the field indicating the number of sidelink time slots can be used, in part, to indicate the number of time slots used for sidelink communication out of all time slots included in the first transmission period, and also in part, to indicate the number of time slots used for sidelink communication out of all time slots included in the second transmission period. In short, depending on whether one or two transmission periods are determined by the transmission period and the transmission period pattern, the method for interpreting the field indicating the number of sidelink time slots can differ. The size of this field can be 8 bits or any other number of bits.

[0229] When the information indicating sidelink resources in the PSBCH is 12 bits, this information can consist of a 3-bit field indicating the transmission period, a 1-bit field indicating the transmission period pattern, and an 8-bit field indicating the number of sidelink slots. Furthermore, the information indicating sidelink resources is assumed to be based on a reference subcarrier spacing of 15 kHz. The transmission period value indicated by the 3-bit transmission period field can be all or some of 0.5, 1, 2, 4, 5, 10, and 20 ms. The 1-bit transmission period pattern field indicates whether the transmission period value represents one transmission period or a combination of two transmission periods. That is, the transmission period pattern indicates whether only one transmission period or two transmission periods exist. When indicating only one transmission period, the entire 8-bit field indicating the number of sidelink slots indicates information about the number of slots used for the sidelink within the transmission period. Alternatively, when the maximum transmission period is 20 ms at 15 kHz, there are only 20 slots, so it is possible to indicate the number of sidelink slots using only the 5 bits of the LSB, allowing the remaining MSB bits to have a fixed value of 0 or 1.

[0230] When there are two transmission cycles, the 8-bit field indicating the number of sidelink time slots is split into two fields. That is, the 4-bit MBS indicates the number of sidelink time slots in all time slots of the first transmission cycle, and the 4-bit LSB indicates the number of sidelink time slots in all time slots of the second transmission cycle. For example, when the indicated transmission cycle is 20ms and the transmission cycle mode has two transmission cycles, each of the first and second transmission cycles can have a length of 10ms. In other words, the sum of the first and second transmission cycles becomes the value indicated by the transmission cycle field.

[0231] Alternatively, when the indicated transmission period is 10 ms and the transmission period mode has two transmission periods, each of the first and second transmission periods can have a length of 10 ms equal to the value indicated by the transmission period field. According to the method described above, in the 8 bits of the field indicating the number of side link slots, the first 4 bits are used to indicate the number of side link slots in the 10 ms first transmission period, and the last 4 bits are used to indicate the number of side link slots in the 10 ms second transmission period. Therefore, the UE can receive information indicating different numbers of side link slots relative to the first and second transmission periods.

[0232] A time slot with a 15kHz subcarrier spacing will have the same time length as two time slots with a 30kHz subcarrier spacing, four time slots with a 60kHz subcarrier spacing, and eight time slots with a 120kHz subcarrier spacing. Therefore, when synchronizing an SSB with a subcarrier spacing different from 15kHz, and then performing communication for sidelink communication with that subcarrier spacing, the UE will reinterpret the sidelink resource information indicated by the 15kHz subcarrier spacing as sidelink resource information with the subcarrier spacing used in synchronization, and then perform sidelink communication. In other words, when configuring a specific time slot for sidelink resources using sidelink resource information indicated by a 15kHz subcarrier spacing, the UE will determine the time slots in which at least one symbol (or all symbols in that time slot) partially overlaps with that specific time slot in terms of time resources as the resource area configured for sidelink communication. Although it is assumed that the reference subcarrier spacing indicating the sidelink resource information is 15kHz, any other subcarrier spacing value can be used. FR1 and FR2 can have the same or different reference subcarrier spacing values.

[0233] The field indicating the transmission period and the field indicating the transmission period pattern can be formed by separate, different bit fields. Alternatively, in a single bit field, a single bit value can indicate both the transmission period and the transmission period pattern.

[0234] exist Figure 17In this context, the two transmission periods P1 and P2 are determined by a field indicating the transmission period and a field indicating the transmission period mode. The sum of P1 and P2 should be a value divided by 20ms without pauses. Alternatively, in... Figure 17 In this context, the value of only one of the two transmission cycles, P1 or P2, can be determined by the fields indicating the transmission cycle and the field indicating the transmission cycle mode. For example, Table 3 below shows information about this index, P1, and P2.

[0235] Table 3

[0236] index P1 P2 1 0.5ms 0.5ms 2 1 ms 1ms 3 0.5 ms 2ms 4 ... ...

[0237] Referring to Table 3, the transmission period field indicates transmission periods P1 and P2, and the transmission period mode field indicates whether only the P1 value is used or both the P1 and P2 values ​​are used together.

[0238] Alternatively, as shown in Table 4 below, if the value indicated by a specific index has only one P1 value, it is determined to be a mode that considers only one transmission cycle, and if the value indicated by another specific index has both P1 and P2 values, it is considered to be a mode that considers two transmission cycles. For example, in Table 4, when the index indicates 3, the UE determines a transmission cycle that repeats for 0.5 ms. Conversely, when the index indicates 1, the UE determines a combination of a first transmission cycle that repeats for 0.5 ms and a second transmission cycle that repeats for 0.5 ms as a combined transmission cycle.

[0239] Table 4

[0240] index P1 P2 1 0.5ms 0.5ms 2 1 ms 1ms 3 0.5ms 4 ... ...

[0241] The bit field indicating the number of sidelink time slots indicates how many sidelink time slots are actually included in the time slots within the configured transmission period. The number of time slots is determined by the configured transmission period and subcarrier spacing, where the transmission period is indicated by the transmission period field, and the subcarrier spacing can follow the sidelink synchronization signal or a value defined in the standard.

[0242] When following the values ​​defined in the standard, the subcarrier spacing can have different or the same values ​​according to FR1 and FR2. When the bit field indicating the number of sidelink slots is N bits, and when the total number of slots in the transmission period indicated by the corresponding bit field is K, the granularity indicated by the bit field indicating the number of sidelink slots can be ceiling(K / 2). N ), floor(K / 2 N ), round(K / 2 N ) or max(floor(K / 2 NThe number of slots for a side link can be determined by at least one of max(floor(40 / 16), 1), or a combination thereof. For example, if the total number of slots in a particular transmission period is 40, and the size of the bit field indicating that period is 4 bits, then the number of slots used for the side link can be indicated at intervals of max(floor(40 / 16), 1) = 2. That is, each of the 16 values ​​can indicate one of 2, 4, 6, 8, ..., 32 values ​​from the end of the transmission period as the value of the number of slots used for the side link. When the bit field indicating the number of side link slots indicates two transmission periods, different bit fields can be used, in which case the field sizes can be equal or different depending on the configured transmission period.

[0243] Alternatively, as shown in Table 5 below, the number of uplink time slots (or the number of time slots available for sidelink resources) can be indicated to the UE based on the transmission period, transmission period mode, and the total number of time slots within a specific transmission period. The 4-bit information used to provide transmission period information indicates one of the index values ​​in Table 5 (indexes 1 to 16) and provides the associated transmission period information P1 and P2. Additionally, the 1-bit information used to provide transmission period mode information indicates whether only one of transmission period mode 1 (P1) and transmission period mode 2 (P2) is used, or both. When only one of transmission period modes 1 and 2 is used, it can indicate that only one specific mode from the standard is used, or a specific value can be determined by another higher-layer signal.

[0244] In Table 5, 'μ' is a code that provides subcarrier spacing information, where μ=1 is 15kHz, μ=2 is 30kHz, μ=3 is 60kHz, μ=4 is 120kHz, and μ=5 is 240kHz. That is, depending on the value of 'μ', the subcarrier spacing is typically expressed as 15*2. μ kHz. Using 1 bit and 4 bits of information, the UE can determine whether the unit of the transmission period indicating the number of UL time slots includes one or more transmission periods, and can determine the total number of time slots (S1, S2) within a specific transmission period based on the subcarrier spacing. When only S1 or S2 is indicated, 8 bits are used to indicate whether the last 2^8 time slots out of all time slots in the S1 or S2 transmission period are allocated as uplink time slots. When both S1 and S2 are indicated, N1 bits and N2 bits are used to indicate whether the last 2^N1 time slots and the last 2^N2 time slots out of all time slots in the S1 and S2 transmission periods are allocated as uplink time slots, respectively. The sum of N1 and N2 is 8 bits.

[0245] In Table 5 below, the index containing 0.625ms is only valid when μ=3, the index containing 1.25ms is only valid when μ=2 or 3, and the index containing 2.5ms is only valid when μ=1, 2, or 3. In summary, sidelink TDD configuration information can be determined using 13 bits (i.e., 1+4+8=13) or 12 bits excluding the bit indicating the transmission cycle mode (i.e., 4+8=12). In this case, it is assumed that two transmission cycle modes, P1 and P2, are always notified to the UE. If one transmission cycle mode exists, and even if the PSBCH defaults to notifying two transmission cycle modes, the transmission cycle and the number of uplink slots within it can always be set to the same value, so Uu can effectively operate as if indicating a single transmission cycle.

[0246] Table 5

[0247]

[0248] At 0.5 ms and μ = 0, the transmission period has 7 symbol units. Therefore, the UE does not consider this valid information and may consider it an error. Alternatively, at 0.5 ms and μ = 0, the UE can always determine that all resources are configured as uplink resources. The value of μ can be obtained from the sidelink synchronization signal, or applied as a common or separate value to FR1 and FR2 according to the 3GPP standard, so that the UE can consider it always fixed. When the value of μ in each of FR1 and FR2 is fixed, the UE can have a different value of μ than that obtained from the sidelink synchronization signal. For example, when μ is defined as 60 kHz in Table 5, the UE can obtain a synchronization signal of 15 kHz. Therefore, if slot information is provided with a subcarrier spacing of 60 kHz when the sidelink slot unit is considered as a 15 kHz subcarrier spacing, the UE will only determine the slot based on the 15 kHz subcarrier spacing as an uplink slot if all slots based on the 60 kHz subcarrier spacing contained in a slot based on the 15 kHz subcarrier spacing are configured as uplink slots. In other words, when a time slot based on a 15kHz subcarrier spacing contains four time slots based on a 60kHz subcarrier spacing, and when at least one of the four time slots based on the 60kHz subcarrier spacing indicates a time slot other than an uplink time slot, the UE determines that the time slot based on the 15kHz subcarrier spacing is not an uplink time slot. If the bit field indicating the number of sidelink time slots (or the number of uplink time slots) included in each transmission cycle is N bits, and when the total number of time slots in the transmission cycle to be indicated by the corresponding bit field is K, the granularity indicated by the bit field indicating the number of sidelink time slots uses ceiling(K / 2). N ), floor(K / 2 N ), round(K / 2N ) or max(floor(K / 2 N Determined by at least one of ), 1), or a combination thereof.

[0249] Figure 18 A method for setting sidelink resource information according to an embodiment is shown.

[0250] In the PSBCH field, TDD configuration information is used to provide time slot information for sending and receiving sidelink data to and from the UE. Specifically, based on the TDD common information of the base station operating in the Uu, the UE can use sidelink resources to notify another UE of UL time slots. The TDD configuration information is divided into the following detailed elements. The subcarrier spacing indicated in the TDD configuration information can be obtained from the synchronization signal, determined based on a reference subcarrier spacing value for a specific frequency or transmission period, determined through the common uplink signal or L1 signal, or determined through other field information of the PSBCH. For example, when the subcarrier spacing obtained by the UE through the sidelink synchronization signal is 15kHz, the UE considers the TDD configuration information to be based on a 15kHz configuration. In another example, such as... Figure 17 As shown, the subcarrier spacing (or the value of μ) can be obtained from the sidelink synchronization signal, or applied as a common or separate value to FR1 and FR2 according to the 3GPP standard, so that the UE can treat it as always fixed.

[0251] When the μ value is fixed for each of FR1 and FR2, the UE can have a different μ value than that obtained from the sidelink synchronization signal. In yet another example, the subcarrier spacing and cyclic prefix (CP) used in the sidelink synchronization signal are pre-configured or predefined values ​​for each frequency band, each region, each resource pool, or a combination thereof, and the UE can use them. For example, when using frequency B in region A, the UE can perform access using the normal cyclic prefix and a subcarrier spacing of 15 kHz.

[0252] - Transmission cycle mode number indicator: This indicates the number of transmission cycle modes. Figure 18 In this context, it indicates whether a transmission cycle consists of one mode 1800 or two modes 1802. One mode indicates the number of UL slots (S1) in one transmission cycle (P1), and two modes indicate the corresponding number of UL slots (S1, S2) in two separate transmission cycles (P1, P2). For example, the transmission cycle mode number indicator can be formed by 1 bit.

[0253] - Transmission Cycle Indicator: This indicator, based on the number of transmission cycle modes, indicates one or two transmission cycles. For example, as shown in Table 6 below, it can indicate (multiple) transmission cycles depending on the number of transmission cycle modes. In another example, the transmission cycle indicator can be formed of 4 bits to indicate (multiple) transmission cycles, as shown in Table 6.

[0254] Table 6

[0255]

[0256] - UL Slot Count Indicator: This indicator is interchangeable with the sidelink slot count indicator and indicates how many slots in a transmission cycle are designated as UL slots. For example, if a transmission cycle consists of 10 slots and the UL slot count indicator has a value of 3, then the last 3 slots out of the 10 slots are configured as UL slots. The UL slot count indicator can be formed by n bits. When a transmission cycle mode is indicated, the UL slot count indicator indicates the number of UL slots (S1) within transmission cycle P1. When two transmission cycle modes are indicated, the UL slot count indicator simultaneously indicates the number of UL slots (S1, S2) within each transmission cycle (P1, P2). For this purpose, equation (1) or equation (1A) below can be used.

[0257] [Equation 1]

[0258] SIV = C1' * B' + A'

[0259] in O≤A≤C1,O≤B≤C2

[0260] [Equation 1A]

[0261] SIV = C1'*B'+A' where O≤A≤C1,O≤B≤C2

[0262] In equation (1) or (1A), 'SIV' is an abbreviation for the sidelink resource indicator value and is used to represent the value of the UL slot quantity indicator in another term. SIV is merely an example, and other abbreviations or terms with similar meanings may be used. 'C1' is the total number of slots included in the transmission cycle (P1) of the first mode, and 'C2' is the total number of slots included in the transmission cycle (P2) of the second mode. 'A' is the number of actual UL slots (S1) indicated by the UL slot quantity indicator in the transmission cycle (P1) of the first mode, and 'B' is the number of actual UL slots (S2) indicated by the UL slot quantity indicator in the transmission cycle (P2) of the second mode. 'K' is a value determined by 'C1', 'C2', and the number of bits (n) of the UL slot quantity indicator. For example, when (C1+1)·(C2+1)>2n, K is Otherwise, K is 1. Alternatively, regardless of the above conditions, the following can be applied.

[0263] In another example, SIV can be expressed as A = 0, 1*K, 2*K, ..., using equation (1) or (1A). The unit indicates the UL time slot in the first transmission cycle, and is expressed as B = 0, 1*K, 2*K, ... The unit indicates the UL time slot in the second transmission cycle.

[0264] When the transmission cycle mode number indicator indicates only one mode, the UE treats the values ​​of the second transmission cycle (P2), the total number of time slots contained in the transmission cycle (P2) of the second mode (C2), and the actual number of UL time slots indicated by the UL time slot number indicator in the transmission cycle (P2) of the second mode (S2) as 0, so that equation (1) or (1A) becomes SIV = A'.

[0265] Furthermore, when only one pattern is indicated, K = 1 can be considered regardless of the conditions described above used to determine the value of K. The floor function applied in equation (1) or (1A) You can use the floor function ([]) or the floor function (round down) in part or in full. Instead. Similarly, in The floor function used in China You can use the rounding function ([]) or the round-down function. Substitute. For example, in (C1+1)·(C2+1)>2 7 (When the UL slot number indicator is 7 bits (n=7)) Otherwise, K = 1.

[0266] In another example, when the two transmission cycle patterns are indicated by equation (1) or (1A), S1 has values ​​of 0*K, 1*K, 2*K, 3*K, etc., and S2 has values ​​of 0*K, 1*K, 2*K, 3*K, etc. Equation [1] is available when the corresponding transmission cycle patterns apply the same K value, and equation (2) is available when the corresponding transmission cycle patterns apply different K values.

[0267] [Equation 2]

[0268] SIV=C1′*B′+A′

[0269] in O≤A≤C1,O≤B≤C2

[0270] Equation (2) has a similar concept to equations (1) or (1A), but uses the values ​​K1 and K2 instead of the value K. K1 is a value determined by the number of bits (n) of C1 and the UL slot quantity indicator, and K2 is a value determined by the number of bits (n) of C2 and the UL slot quantity indicator. For example, in (C1+1)>sqrt(2 n )hour, Otherwise, K = 1. For example, in (C² + 1) > sqrt(2... n )hour, Otherwise, K = 1. Generally, in (C i +1)>sqrt(2 n )hour, Otherwise, K = 1. Alternatively, regardless of the above conditions, the following can be applied: or

[0271] When only one mode is indicated, regardless of the conditions described above used to determine the value of K1, K1 can be considered to be 1, and K2 is not present. In another example, when the UL slot count indicator is 7 bits, the value of 'n' in the above equation can be n = 7. The floor function applied in the above equation... You can use the rounding function ([]) or the round-down function. replace.

[0272] In another example, the UL slot quantity indicator information can be communicated via equation (3) as shown below.

[0273] SIV=(C1+1)*B+A

[0274] Where O≤A≤C1, O≤B≤C2

[0275] Equation (3) uses a definition similar to that of Equation (1) or (1A) or Equation (2), but without a K value. Instead, the reference subcarrier spacing indicating the UL slot quantity indicator information is determined based on a specific value determined by the transmission cycle mode quantity indicator and the transmission cycle indicator. For example, when operating with a 120 kHz subcarrier spacing on sidelink resources, if the UL slot quantity indicator information is indicated by the transmission cycle mode quantity indicator and the transmission cycle indicator based on a 15 kHz subcarrier spacing, the UE can consider one UL slot indicated based on the 15 kHz subcarrier spacing as being applied to a total of 8 slots.

[0276] Figure 19 The time slot structure of the subcarrier spacing according to an embodiment is shown. Figure 19 In the diagram, reference numeral 1900 indicates a time slot structure based on 15kHz, reference numeral 1902 indicates a time slot structure based on 30kHz, and reference numeral 1904 indicates a time slot structure based on 60kHz. For example, when a UE receives TDD configuration information based on a normal cyclic prefix and 15kHz, but sidelink communication actually operates at 60kHz and a normal cyclic prefix, the UE can receive TDD configuration information based on 1900. Figure 19 Slots 13 and 14 in 1904 are used as information for UL slots (or sidelink communication slots). In this case, the UE determines that slots 13a, 13b, 13c, 13d, 14a, 14b, 14c, and 14d in 1904 are configured as UL slots (or sidelink communication slots) for actually performing sidelink communication. In another example, the UE may assume that equation (3) is always based on a 15kHz subcarrier spacing and a normal cyclic prefix to provide TDD configuration information. In yet another example, in the TDD configuration information, the normal cyclic prefix and the reference subcarrier spacing (μ k ) can be determined by the following equation (4).

[0277] [Equation 4]

[0278]

[0279] The definitions and candidate values ​​of C1, C2, and n in equation [4] are the same as those described in equations (1) or (1A) to (3) above. i 'μ' represents the subcarrier spacing during which the UE actually performs sidelink communication. The relationship between the 'μ' value and the subcarrier spacing is shown in Table 7 below. For example, when the UE performs sidelink communication at 120kHz, the transmission period mode is set to 2(P1, P2), each transmission period is 10ms (P1 = 10ms, P2 = 10ms, i.e., C1 = C2 = 80), and 'n' is 7 bits. Through the above equation 'μ'... kThe value is set to 0, and the UE determines the number of UL slots (or slots used for sidelink communication) based on a reference subcarrier spacing of 15 kHz, such as... Figure 19 Or as shown in 20.

[0280] In summary, according to equation (4), based on the total number of time slots (C1, C2) of each transmission cycle indicated by the transmission cycle mode number indicator and transmission cycle indicator in the TDD configuration information, the number of bits (n) of the UL time slot number indicator in the TDD configuration information, and the subcarrier spacing value (μ) of the UE actually performing sidelink communication, the calculation is as follows: i ), to determine the reference subcarrier spacing value (μ) applied to the UL slot quantity indicator. k As shown in Table 7 below, the subcarrier spacing values ​​(μ) used for actual sidelink communication are... i The value can be pre-configured by the UE based on each frequency band, each region, each resource pool, or a combination thereof. The floor function applied in equation (4) You can use the rounding function ([]) or the round-down function. To replace.

[0281] Table 7

[0282] Subcarrier spacing (kHz) <![CDATA[μ (for example, μ_ i or μ_k)]]> 15 0 30 1 60 2 120 3 240 4

[0283] In Table 7, the TDD configuration information can have a total of 12 bits, including a 1-bit transmission cycle mode number indicator, a 4-bit transmission cycle indicator, and a 7-bit UL timeslot number indicator.

[0284] It should be understood that each block and combination of blocks in the flowchart illustration can be implemented by a processor provided to a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to generate machine-readable instructions, such that the instructions, executed by the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart block or blocks. These computer program instructions can also be stored in a computer-usable or computer-readable storage medium, which can instruct the computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-usable or computer-readable storage medium produce an article of manufacture including instruction means for implementing the functions specified in the flowchart block or blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus, thereby producing a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more blocks of the flowchart.

[0285] Furthermore, each block of the flowchart may indicate a module, code segment, or code section, which includes one or more executable instructions for implementing a specified logical function(s). In some alternative implementations, the functions mentioned in a block may appear out of order. For example, two blocks shown consecutively may actually be executed substantially simultaneously, or these blocks may sometimes be executed in reverse order, depending on the functions involved.

[0286] As used herein, the term "unit" refers to a software or hardware element that performs a predetermined function, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, the term "unit" is not always limited to software or hardware. A "unit" can be configured to be stored in addressable memory or to execute one or more processors. Therefore, a "unit" includes software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided by elements and units can be combined into functionality of fewer elements and units, or divided into functionality of more elements and units. Furthermore, elements and units can be implemented as one or more central processing units (CPUs) within an operating device or secure multimedia card. This unit may include one or more processors.

[0287] While this disclosure has been specifically shown and described with reference to certain embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the subject matter as defined by the appended claims.

Claims

1. A method performed by a user equipment in a wireless communication system, the method comprising: Obtain time division duplex (TDD) configuration information associated with at least one time slot used for sidelink communication; as well as Send the Physical Sidelink Broadcast Channel (PSBCH) containing the TDD configuration information. The TDD configuration information includes first information, second information, and third information. Among them, based on the number of the first information indication patterns Wherein, when the number of modes is 1: (i) the period of the first mode is indicated based on the second information, and (ii) the number of uplink UL slots of the first mode is indicated based on the third information, and Wherein, when the number of modes is 2: (i) the period of the first mode and the period of the second mode are indicated based on the second information, and (ii) the number of UL slots of the first mode and the number of UL slots of the second mode are indicated based on the third information.

2. The method as described in claim 1, wherein, The third piece of information corresponds to the number of UL time slots used for sidelink communication.

3. The method as described in claim 1, wherein, The TDD configuration information corresponds to 12 bits, and Wherein, the first information corresponds to 1 bit in the 12 bits, the second information corresponds to 4 bits in the 12 bits, and the third information corresponds to 7 bits in the 12 bits.

4. A method performed by a user equipment in a wireless communication system, the method comprising: Receive physical side link broadcast channel PSBCH; as well as Based on the PSBCH, time-division duplex (TDD) configuration information associated with sidelink communication is obtained, wherein the TDD configuration information includes first information, second information, and third information. Among them, based on the number of the first information indication patterns Wherein, when the number of modes is 1: (i) the period of the first mode is indicated based on the second information, and (ii) the number of uplink UL slots of the first mode is indicated based on the third information, and Wherein, when the number of modes is 2: (i) the period of the first mode and the period of the second mode are indicated based on the second information, and (ii) the number of UL slots of the first mode and the number of UL slots of the second mode are indicated based on the third information.

5. The method of claim 4, wherein, The third piece of information corresponds to the number of UL time slots used for sidelink communication.

6. The method of claim 4, wherein, The TDD configuration information corresponds to 12 bits, and Wherein, the first information corresponds to 1 bit in the 12 bits, the second information corresponds to 4 bits in the 12 bits, and the third information corresponds to 7 bits in the 12 bits.

7. A user equipment (UE) in a wireless communication system, the UE comprising: transceiver; and The processor, coupled to the transceiver, is configured to: Obtain time division duplex (TDD) configuration information associated with at least one time slot used for sidelink communication; as well as Send the Physical Sidelink Broadcast Channel (PSBCH) containing the TDD configuration information. The TDD configuration information includes first information, second information, and third information. Among them, based on the number of the first information indication patterns Wherein, when the number of modes is 1: (i) the period of the first mode is indicated based on the second information, and (ii) the number of uplink UL slots of the first mode is indicated based on the third information, and Wherein, when the number of modes is 2: (i) the period of the first mode and the period of the second mode are indicated based on the second information, and (ii) the number of UL slots of the first mode and the number of UL slots of the second mode are indicated based on the third information.

8. The UE as claimed in claim 7, wherein, The third piece of information corresponds to the number of UL time slots used for sidelink communication.

9. The UE as claimed in claim 7, wherein, The TDD configuration information corresponds to 12 bits, and Wherein, the first information corresponds to 1 bit in the 12 bits, the second information corresponds to 4 bits in the 12 bits, and the third information corresponds to 7 bits in the 12 bits.

10. A user equipment (UE) in a wireless communication system, the UE comprising: transceiver; and The processor, coupled to the transceiver, is configured to: Receive physical side link broadcast channel PSBCH; as well as Based on the PSBCH, obtain the Time Division Duplex (TDD) configuration information associated with side link communication. The TDD configuration information includes first information, second information, and third information. Among them, based on the number of the first information indication patterns Wherein, when the number of modes is 1: (i) the period of the first mode is indicated based on the second information, and (ii) the number of uplink UL slots of the first mode is indicated based on the third information, and Wherein, when the number of modes is 2: (i) the period of the first mode and the period of the second mode are indicated based on the second information, and (ii) the number of UL slots of the first mode and the number of UL slots of the second mode are indicated based on the third information.

11. The UE as claimed in claim 10, wherein, The third piece of information corresponds to the number of UL time slots used for sidelink communication.

12. The UE as claimed in claim 10, wherein, The TDD configuration information corresponds to 12 bits, and Wherein, the first information corresponds to 1 bit in the 12 bits, the second information corresponds to 4 bits in the 12 bits, and the third information corresponds to 7 bits in the 12 bits.

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