Method for receiving and transmitting downlink control information and terminal using the same

Abstract

A method for receiving and transmitting downlink control information and a terminal using the method are provided. The method is characterized in that: a sidelink SPS activation / release DCI for indicating activation or release of sidelink semi-static scheduling (SPS) is generated; and the sidelink SPS activation / release DCI is transmitted to a terminal, wherein the sidelink SPS activation / release DCI further includes a sidelink SPS activation / release field and a sidelink SPS configuration index field that do not exist in a sidelink dynamic DCI for dynamically scheduling a sidelink.

Description

[0001] This application is a divisional application of the patent application with the original application number 201780022181.X (International Application No.: PCT / KR2017 / 003657, filing date: April 3, 2017, invention title: Method for transmitting downlink control information for sidelink scheduling in a wireless communication system and terminal using the same). Technical Field

[0002] The present invention relates to wireless communication, and more particularly, to a method for transmitting downlink control information for sidelink scheduling in a wireless communication system and a terminal using the same. Background Art

[0003] In the International Telecommunication Union Radiocommunication Sector (ITU-R), standardization work for International Mobile Telecommunications (IMT)-Advanced (i.e., the next generation mobile communication system from the third generation onwards) is underway. IMT-Advanced aims to support Internet Protocol (IP)-based multimedia services at a data transfer rate of 1 Gbps in stationary and slow-moving states and 100 Mbps in fast-moving states.

[0004] For example, the 3rd Generation Partnership Project (3GPP) is a system standard that meets the requirements of IMT-Advanced and is prepared for LTE-Advanced (LTE Advanced), which is an improvement over Long Term Evolution (LTE) based on an Orthogonal Frequency Division Multiple Access (OFDMA) / Single Carrier - Frequency Division Multiple Access (SC-FDMA) transmission scheme. LTE-Advanced is one of the strong candidates for IMT-Advanced.

[0005] Attention to device-to-device (D2D) technology for direct communication between devices is increasing. Specifically, D2D has become a focus of attention as a communication technology for public safety networks. Commercial communication networks are rapidly transitioning to LTE, but due to issues of conflict with existing communication standards and costs, current public safety networks are basically based on 2G technology. This technology gap and the demand for improved services have led to efforts to improve public safety networks.

[0006] Public safety networks have higher service requirements (reliability and security) than commercial communication networks. Specifically, if the coverage of cellular communication is not affected or available, public safety networks also require direct communication between devices, i.e., D2D operation.

[0007] Since D2D operations are communications between neighboring devices, they can have various advantages. For example, D2D UEs have high transmission rates and low latency and can perform data communication. In addition, in D2D operations, traffic concentrated on the base station can be dispersed. If a D2D UE acts as a relay, it can also act to extend the coverage area of the base station.

[0008] The above D2D communication can be extended and applied to signal transmission and / or reception between vehicles. Most specifically, communication related to vehicles is referred to as vehicle-to-everything (V2X) communication.

[0009] In V2X, the term "X" can refer to pedestrians, vehicles, infrastructure / networks, etc., which can be respectively indicated as V2P, V2V, and V2I / N.

[0010] Meanwhile, a wireless communication system can send signals by using semi-static scheduling (SPS). Here, semi-static scheduling (SPS) corresponds to the following scheduling method: First, a cycle period for sending signals is predetermined through a higher layer signal, and then signals are sent according to the predetermined cycle period using a modulation and coding scheme (MCS), resources, etc. indicated by a control channel, while guiding (or indicating) the activation of SPS through the control channel when notifying (or informing) specific resources. Signal transmission according to the above SPS can also be used for V2X communication.

[0011] In addition, a device-to-device direct link can also be referred to as a sidelink. Both a dynamic method and a semi-static method can be used as scheduling methods in the sidelink. In this regard, since the characteristics of downlink control information for dynamically performing scheduling are different from the characteristics of downlink control information for semi-statically performing scheduling, it may not be preferable to use downlink control information configured to have the same format. SUMMARY OF THE INVENTION

[0012] TECHNICAL PROBLEM

[0013] An object to be achieved by the present invention is to provide a method for transmitting downlink control information for sidelink scheduling in a wireless communication system and a terminal using the method.

[0014] TECHNICAL SOLUTION

[0015] In one aspect, a method for transmitting downlink control information for sidelink scheduling in a wireless communication system is provided. The method includes the steps of: generating sidelink SPS activation / release DCI indicating activation or release of sidelink semi-static scheduling (SPS); and transmitting the sidelink SPS activation / release DCI to a user equipment (UE). The sidelink SPS activation / release DCI further includes a sidelink SPS configuration index field and a sidelink SPS activation / release field that do not exist in sidelink dynamic DCI, and the sidelink dynamic DCI performs dynamic scheduling of the sidelink.

[0016] The sidelink SPS configuration index field may include information indicating one sidelink SPS configuration among a plurality of sidelink SPS configurations.

[0017] The total bit size of the sidelink SPS activation / release DCI may be greater than the total bit size of the sidelink dynamic DCI.

[0018] The sidelink SPS configuration index field may be configured with 3 bits.

[0019] The sidelink SPS activation / release field may be configured with 1 bit.

[0020] In another aspect, a wireless device is provided. The wireless device includes: a radio frequency (RF) unit that transmits and receives radio signals; and a processor operatively connected to the RF unit. The processor is configured to: generate sidelink SPS activation / release DCI indicating activation or release of sidelink semi-static scheduling (SPS); and transmit the sidelink SPS activation / release DCI to a user equipment (UE). The sidelink SPS activation / release DCI further includes a sidelink SPS configuration index field and a sidelink SPS activation / release field that do not exist in sidelink dynamic DCI, and the sidelink dynamic DCI performs dynamic scheduling of the sidelink.

[0021] Advantageous Effects

[0022] Multiple SPS processes / configurations can be configured in the sidelink. According to the present invention, different from the DCI that dynamically schedules the sidelink, the DCI that activates / releases SPS in the sidelink may additionally include a sidelink SPS configuration index field and a sidelink SPS configuration activation / release field that announce which specific SPS configuration the corresponding activation / release is targeted at. Therefore, even in the presence of multiple sidelink SPS configurations, the user equipment (or terminal) and the base station can perform the sidelink SPS process without any ambiguity. Brief Description of the Drawings

[0023] Figure 1 A wireless communication system is shown.

[0024] Figure 2 It is a diagram showing the radio protocol architecture for the user plane.

[0025] Figure 3 It is a diagram showing the radio protocol architecture for the control plane.

[0026] Figure 4 It shows the basic structure of ProSe.

[0027] Figure 5 It shows an example of the deployment of various types of UEs performing ProSe direct communication and the cell coverage.

[0028] Figure 6 It shows the user plane protocol stack for ProSe direct communication.

[0029] Figure 7 It shows the PC5 interface for D2D discovery.

[0030] Figure 8 It shows an example of the existing uplink SPS processing.

[0031] Figure 9 It shows an example of the case where the uplink SPS processing is applied to V2X.

[0032] Figure 10 It shows the UE operation method according to the uplink SPS.

[0033] Figure 11 It is a diagram showing the comparison between the existing (VoIP) uplink SPS activation / release DCI (first DCI) and the V2X uplink SPS activation / release DCI (second DCI) by applying [Proposed Method #2].

[0034] Figure 12 It shows an example of the method for interpreting specific fields when decoding the first DCI and the second DCI.

[0035] Figure 13 It is a diagram showing the comparison between the DCI for dynamically scheduling the sidelink channel (DCI for dynamic scheduling (V2X SL dynamic DCI)) and the sidelink channel SPS activation / release DCI (V2X SL SPS activation / release DCI).

[0036] Figure 14 It shows an example of the method for transmitting downlink control information for sidelink scheduling according to another exemplary embodiment of the present invention.

[0037] Figure 15An example of a method for performing SPS processing according to yet another exemplary embodiment of the present invention is shown.

[0038] Figure 16 Examples of verifying DCI as a DCI format for V2X sidelink SPS activation / release or verifying it as V2X sidelink dynamic DCI are described.

[0039] Figure 17 An example of using 2 reports simultaneously is shown.

[0040] Figure 18 It is a block diagram of a UE in which an embodiment of the present invention is implemented. Detailed Description

[0041] Figure 1 A wireless communication system is shown.

[0042] For example, the wireless communication system may be referred to as an evolved UMTS terrestrial radio access network (E-UTRAN) or a Long Term Evolution (LTE) / LTE-A system.

[0043] The E-UTRAN includes at least one base station (BS) 20 that provides a control plane and a user plane to a user equipment (UE) 10. The UE 10 may be fixed or mobile and may be referred to by another term such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a mobile terminal (MT), a wireless device, etc. The BS 20 is generally a fixed station that communicates with the UE 10 and may be referred to by another term such as an evolved Node B (eNB), a base transceiver system (BTS), an access point, etc.

[0044] The BSs 20 are interconnected via an X2 interface. The BS 20 is also connected to an evolved packet core (EPC) 30 via an S1 interface, more specifically, connected to a mobility management entity (MME) via S1-MME and connected to a serving gateway (S-GW) via S1-U.

[0045] The EPC 30 includes an MME, an S-GW, and a packet data network gateway (P-GW). The MME has access information of the UE or capability information of the UE, which is generally used for mobility management of the UE. The S-GW is a gateway that terminates at the E-UTRAN. The P-GW is a gateway that terminates at a PDN.

[0046] The layers of the radio interface protocol between the UE and the network can be classified into the first layer (L1), the second layer (L2), and the third layer (L3) based on the lower three layers of the well-known Open System Interconnection (OSI) model in the communication system. Among them, the physical (PHY) layer belonging to the first layer provides an information transfer service by using physical channels, and the radio resource control (RRC) layer belonging to the third layer is used to control the radio resources between the UE and the network. For this purpose, the RRC layer exchanges RRC messages between the UE and the BS.

[0047] Figure 2 is a diagram showing the radio protocol architecture for the user plane. Figure 3 is a diagram showing the radio protocol architecture for the control plane. The user plane is a protocol stack for user data transmission. The control plane is a protocol stack for control signal transmission.

[0048] Referring to Figure 2 and Figure 3 the PHY layer provides an information transfer service to the upper layer through physical channels. The PHY layer is connected to the medium access control (MAC) layer, which is the upper layer of the PHY layer, through transport channels. Data is transmitted between the MAC layer and the PHY layer through transport channels. Transport channels are classified according to how data is transmitted through the radio interface and what characteristics the data transmitted through the radio interface has.

[0049] Data moves between different PHY layers (i.e., the PHY layer of the transmitter and the PHY layer of the receiver) through physical channels. Physical channels can be modulated according to the orthogonal frequency division multiplexing (OFDM) scheme and use time and frequency as radio resources.

[0050] The functions of the MAC layer include the mapping between logical channels and transport channels and the multiplexing and demultiplexing of transport blocks provided through physical channels on the transport channels belonging to the MAC service data unit (SDU) of the logical channel. The MAC layer provides services to the radio link control (RLC) layer through logical channels.

[0051] The functions of the RLC layer include the concatenation, segmentation, and reassembly of RLC SDUs. To ensure various types of quality of service (QoS) required for radio bearers (RB), the RLC layer provides three types of operation modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). AM RLC provides error correction through automatic repeat request (ARQ).

[0052] The RRC layer is only defined on the control plane. The RRC layer is related to the configuration, reconfiguration, and release of radio bearers, and is responsible for the control of logical channels, transport channels, and PHY channels. RB refers to the logical route provided by the first layer (PHY layer) and the second layer (MAC layer, RLC layer, and PDCP layer) for transmitting data between the UE and the network.

[0053] The functions of the Packet Data Convergence Protocol (PDCP) layer on the user plane include the transmission of user data, as well as header compression and encryption. The functions of the PDCP layer on the user plane also include the transmission and encryption / integrity protection of control plane data.

[0054] Configuring an RB means defining the characteristics of radio protocol layers and channels to provide a specific service and configuring various detailed parameters and operation methods. RBs can be divided into two types: signaling RBs (SRBs) and data RBs (DRBs). SRBs are used as the channels through which RRC messages are sent on the control plane, and DRBs are used as the channels through which user data is sent on the user plane.

[0055] If an RRC connection is established between the RRC layer of the UE and the RRC layer of the E-UTRAN, the UE is in the RRC connected state. Otherwise, the UE is in the RRC idle state.

[0056] The downlink transport channels for sending data from the network to the UE include the Broadcast Channel (BCH) for sending system information and the Downlink Shared Channel (SCH) for sending user services or control messages. The services or control messages of downlink multicast or broadcast services can be sent through the downlink SCH, or can be sent through an additional Downlink Multicast Channel (MCH). In addition, the uplink transport channels for sending data from the UE to the network include the Random Access Channel (RACH) for sending initial control messages and the Uplink Shared Channel (SCH) for sending user services or control messages.

[0057] The logical channels located above the transport channels and mapped to the transport channels include the Broadcast Control Channel (BCCH), Paging Control Channel (PCCH), Common Control Channel (CCCH), Multicast Control Channel (MCCH), and Multicast Traffic Channel (MTCH).

[0058] The physical channel includes a plurality of OFDM symbols in the time domain and a plurality of subcarriers in the frequency domain. A subframe includes a plurality of OFDM symbols in the time domain. An RB is a resource allocation unit and includes a plurality of OFDM symbols and a plurality of subcarriers. Additionally, each subframe may use specific subcarriers of a specific OFDM symbol (e.g., the first OFDM symbol) of the corresponding subframe for the physical downlink control channel (PDCCH), i.e., the L1 / L2 control channel. The transmission time interval (TTI) is the unit time for subframe transmission.

[0059] The RRC state indicates whether the RRC layer of the UE is logically connected to the RRC layer of the E-UTRAN. The case where the RRC layer of the UE is logically connected to the RRC layer of the E-UTRAN is called the RRC connected state. The case where the RRC layer of the UE is not logically connected to the RRC layer of the E-UTRAN is called the RRC idle state. The E-UTRAN can check the presence of the corresponding UE in the RRC connected state in each cell (since the UE has an RRC connection), and thus can effectively control the UE. In contrast, the E-UTRAN cannot check the UE in the RRC idle state, and the core network (CN) manages the UE in the RRC idle state in each tracking area (i.e., a larger area unit than a cell). That is, the presence of the UE in the RRC idle state is checked only for each large area. Therefore, in order to be provided with common mobile communication services such as voice or data, the UE needs to transition to the RRC connected state.

[0060] When the user first turns on the power of the UE, the UE first searches for a suitable cell and remains in the RRC idle state in the corresponding cell. The UE in the RRC idle state establishes an RRC connection with the E-UTRAN through the RRC connection procedure when it is necessary to establish an RRC connection, and transitions to the RRC connected state. The cases where the UE in the RRC idle state needs to establish an RRC connection include various cases. For example, the cases may include the need to send uplink data for reasons such as the user attempting to make a call and sending a response message in response to a paging message received from the E-UTRAN.

[0061] The non-access stratum (NAS) layer located above the RRC layer performs functions such as session management and mobility management.

[0062] In the NAS layer, to manage the mobility of the UE, two types of states are defined: EPS Mobility Management Registered (EMM-REGISTERED) and EMM Deregistered (DEREGISTERED). These two states are applied to the UE and the MME. The UE is initially in the EMM Deregistered state. To access the network, the UE performs a process of registering the UE with the corresponding network through the initial attachment procedure. If the attachment procedure is successfully executed, the UE and the MME become in the EMM Registered state.

[0063] To manage the signaling connection between the UE and the EPC, two types of states are defined: EPS Connection Management Idle (ECM-IDLE) state and ECM Connected (ECM-CONNECTED) state. These two states are applied to the UE and the MME. When a UE in the ECM-IDLE state establishes an RRC connection with the E-UTRAN, the UE becomes in the ECM-CONNECTED state. The MME in the ECM-IDLE state becomes in the ECM-CONNECTED state when it establishes an S1 connection with the E-UTRAN. When the UE is in the ECM-IDLE state, the E-UTRAN does not have information about the context of the UE. Therefore, the UE in the ECM-IDLE state performs processes related to the mobility of the UE (e.g., cell selection or cell reselection) without receiving a command from the network. In contrast, when the UE is in the ECM-CONNECTED state, the mobility of the UE is managed in response to a command from the network. If the location of the UE in the ECM-IDLE state is different from the location known to the network, the UE notifies its corresponding location to the network through the tracking area update procedure.

[0064] Now, D2D operations will be described. In 3GPP LTE-A, the service related to D2D operations is called Proximity-based Service (ProSe). Hereinafter, ProSe is equivalent to D2D operations and ProSe can be interchanged with D2D operations. Now, ProSe will be described.

[0065] ProSe includes ProSe direct communication and ProSe direct discovery. ProSe direct communication is communication performed between two or more neighboring UEs. The UE can perform communication using the protocol of the user plane. A ProSe enabled UE means a UE that supports processes related to the requirements of ProSe. Unless otherwise specified, ProSe enabled UEs include both public safety UEs and non-public safety UEs. A public safety UE is a UE that supports both functions specified for public safety and ProSe processes, and a non-public safety UE is a UE that supports ProSe processes and does not support functions specified for public safety.

[0066] ProSe direct discovery is a process for discovering another ProSe-capable UE adjacent to a ProSe-capable UE. In this case, only the capabilities of two types of ProSe-capable UEs are used. EPC-level ProSe discovery means a process in which the EPC determines whether two types of ProSe-capable UEs are in proximity and notifies the two types of ProSe-capable UEs of the proximity.

[0067] Hereinafter, for convenience, ProSe direct communication may be referred to as D2D communication, and ProSe direct discovery may be referred to as D2D discovery.

[0068] Figure 4 Shows the basic structure of ProSe.

[0069] Refer to Figure 4 , the basic structure for ProSe includes E-UTRAN, EPC, multiple types of UEs including ProSe applications, a ProSe application server (ProSe APP server), and ProSe functions.

[0070] EPC represents the E-UTRAN core network configuration. The EPC may include an MME, S-GW, P-GW, a policy and charging rules function (PCRF), a home subscriber server (HSS), etc.

[0071] The ProSe APP server is a user for generating ProSe capabilities of application functions. The ProSe APP server can communicate with the application in the UE. The application in the UE can use the ProSe capabilities to generate application functions.

[0072] The ProSe function may include at least one of the following functions, but is not necessarily limited thereto.

[0073] - Interworking with third-party applications via reference points

[0074] - Authorization and configuration of UEs for discovery and direct communication

[0075] - Function enabling EPC-level ProSe discovery

[0076] - Processing of ProSe-related new subscriber data and data storage, as well as processing of ProSe identifiers

[0077] - Security-related functions

[0078] - Providing control for policy-related functions to the EPC

[0079] - Providing functions for charging (via the EPC or outside the EPC, e.g., offline charging)

[0080] The reference points and reference interfaces in the basic structure for ProSe are described below.

[0081] - PC1: The reference point between the ProSe application in the UE and the ProSe application in the ProSe APP server. This is used to define the signaling requirements in the application dimension.

[0082] - PC2: The reference point between the ProSe APP server and the ProSe function. This is used to define the interaction between the ProSe APP server and the ProSe function. The update of the application data in the ProSe database of the ProSe function can be an example of this interaction.

[0083] - PC3: The reference point between the UE and the ProSe function. This is used to define the interaction between the UE and the ProSe function. The configuration for ProSe discovery and communication can be an example of this interaction.

[0084] - PC4: The reference point between the EPC and the ProSe function. This is used to define the interaction between the EPC and the ProSe function. This interaction can illustrate the time when the path for 1:1 communication between multiple types of UEs is established or the time when the ProSe service for real-time session management or mobility management is authenticated.

[0085] - PC5: The reference point for discovery and communication, relaying, and 1:1 communication between multiple types of UEs using the control / user plane.

[0086] - PC6: The reference point for functions such as ProSe discovery between users belonging to different PLMNs.

[0087] - SGi: This can be used to exchange application data and various types of application dimension control information.

[0088] D2D operations can be supported when the UE is being served within the coverage of the network (cell) or when it is outside the coverage of the network.

[0089] Figure 5 Deployment examples of various types of UEs performing ProSe direct communication and cell coverage are shown.

[0090] Refer to Figure 5 In (a), various types of UEs A and B can be outside the cell coverage. Refer to Figure 5 In (b), UE A can be within the cell coverage and UE B can be outside the cell coverage. Refer to Figure 5 In (c), various types of UEs A and B can be within the coverage of a single cell. Refer toFigure 5 In (d), UE A may be within the coverage area of the first cell, and UE B may be within the coverage area of the second cell. ProSe direct communication may be performed between various types of UEs located at various positions as Figure 5 described.

[0091] <Radio Resource Allocation for D2D Communication (ProSe Direct Communication)>

[0092] At least one of the following two modes may be used for resource allocation for D2D communication.

[0093] 1. Mode 1

[0094] Mode 1 is a mode in which the eNB schedules resources for ProSe direct communication. To send data according to Mode 1, the UE needs to be in the RRC_CONNECTED (RRC connected) state. The UE requests transmission resources from the eNB. The eNB performs a scheduling assignment and schedules resources for sending data. The UE may send a scheduling request to the eNB and send a ProSe buffer status report (BSR). Based on the ProSe BSR, the eNB has data to be transmitted via ProSe direct communication of the UE and determines the resources required for transmission.

[0095] 2. Mode 2

[0096] Mode 2 is a mode in which the UE directly selects resources. The UE directly selects resources for ProSe direct communication from a resource pool. The resource pool may be configured by the network or may be previously determined.

[0097] Meanwhile, if the UE has a serving cell, that is, if the UE is in the RRC_CONNECTED state with the eNB or is located in a specific cell in the RRC_IDLE (RRC idle) state, the UE is considered to be within the coverage area of the eNB.

[0098] If the UE is outside the coverage area, only Mode 2 can be applied. If the UE is within the coverage area, the UE may use Mode 1 or Mode 2 according to the configuration of the eNB.

[0099] If there is no other exceptional condition, the UE can change the mode from Mode 1 to Mode 2 or from Mode 2 to Mode 1 only when the eNB performs the configuration.

[0100] <D2D Discovery (ProSe Direct Discovery)>

[0101] D2D discovery refers to the process by which a ProSe - capable terminal discovers other ProSe - capable terminals in its vicinity and can be referred to as ProSe direct discovery. The information used for ProSe direct discovery is hereinafter referred to as discovery information.

[0102] The PC 5 interface can be used for D2D discovery. The PC 5 interface includes the MAC layer, the PHY layer, and the ProSe protocol layer (i.e., the higher layer). The higher layer (ProSe protocol) handles the permission for advertisement and the monitoring of discovery information. The content of the discovery information is transparent to the access stratum (AS). The ProSe protocol only conveys valid discovery information to the AS for advertisement. The MAC layer receives the discovery information from the higher layer (ProSe protocol). The IP layer is not used for sending discovery information. The MAC layer determines the resources for advertising the discovery information received from the higher layer. The MAC layer generates a MAC protocol data unit (PDU) for carrying the discovery information and sends the MAC PDU to the physical layer. No MAC header is added.

[0103] For advertising discovery information, there are two types of resource assignments.

[0104] 1. Type 1

[0105] Type 1 is a method of assigning resources for advertising discovery information in a UE - non - specific manner. The eNB provides a resource pool configuration for advertising discovery information to multiple types of UEs. This configuration can be broadcast via SIB. This configuration can be provided via UE - specific RRC messages. Alternatively, this configuration can be broadcast in other layers via non - RRC messages, or can be provided by UE - specific signaling.

[0106] The UE autonomously selects resources from the indicated resource pool and uses the selected resources to advertise discovery information. The UE can advertise discovery information via randomly selected resources during each discovery period.

[0107] 2. Type 2

[0108] Type 2 is a method of assigning resources for advertising discovery information in a UE - specific manner. A UE in the RRC_CONNECTED state can request resources for advertising discovery signals from the eNB via RRC signaling. The eNB can advertise the resources for advertising discovery signals via RRC signaling. Resources for monitoring discovery signals can be assigned within a resource pool configured for multiple types of UEs.

[0109] The eNB 1) can announce the type 1 resource pool for discovery signal announcements to UEs in the RRC_IDLE state through the SIB. The ProSe direct discovery has multiple types of UEs that are permitted to use the type 1 resource pool to announce discovery information in the RRC_IDLE state. Alternatively, the eNB 2) announces through the SIB that the eNB supports ProSe direct discovery, but may not provide resources for discovery information announcements. In this case, the UE needs to enter the RRC_CONNECTED state for discovery information announcements.

[0110] For UEs in the RRC_CONNECTED state, the eNB can configure through RRC signals that the UE must use the type 1 resource pool for discovery information announcements or must use type 2 resources.

[0111] Figure 6 Illustrate the user plane protocol stack for ProSe direct communication.

[0112] Refer to Figure 6 , the PC 5 interface consists of the PDCH, RLC, MAC, and PHY layers.

[0113] In ProSe direct communication, there may be no HARQ feedback. The MAC header can include the source layer-2 ID and the destination layer-2 ID.

[0114] Figure 7 Illustrate the PC 5 interface for D2D discovery.

[0115] Refer to Figure 7 , the PC 5 interface consists of the MAC layer, the PHY layer, and the ProSe protocol layer corresponding to the higher layer. The higher layer (ProSe protocol) is responsible for authorizing the announcement (or notification) and monitoring of discovery information, and the content of the discovery information is transparent to the access layer. The ProSe protocol only allows discovery information that is valid for announcements to be passed to the AS.

[0116] The MAC layer receives discovery information from the higher layer. The IP layer is not used for sending discovery information. The MAC layer determines (or decides) the resources to be used for announcing the discovery information received from the higher layer. The MAC layer generates a MAC protocol data unit (PDU) carrying the discovery information and sends the generated MAC PDU to the physical layer. In this article, no MAC header is added.

[0117] The above operations can also be applied to vehicle-to-everything (V2X). Hereinafter, the device-to-device direct link can be referred to as the sidelink.

[0118] Hereinafter, the present invention will be described in detail.

[0119] First, semi-static scheduling (SPS) will be described in detail.

[0120] In a wireless communication system, a user equipment (UE) receives scheduling information such as DL grants, UL grants, etc. through a PDCCH. Then, based on the received scheduling information, the UE performs operations of receiving a PDSCH and transmitting a PUSCH. Generally, a UL grant and a PDSCH are received within the same subframe. Thereafter, a PUSCH is transmitted at least 4 subframes after the subframe in which the UL grant has been received. In addition to this dynamic scheduling, LTE / LTE-A also provides semi-static scheduling (SPS).

[0121] Downlink or uplink SPS can be notified (or informed) to the UE through a higher layer signal such as radio resource control (RRC) in which subframes semi-static transmission (PUSCH) / reception (PDSCH) is performed. Parameters given as a higher layer signal can correspond to, for example, a cyclic period of subframes and an offset value.

[0122] After identifying SPS transmission / reception through RRC signaling, when the UE receives an activation or release signal for SPS transmission through a physical downlink control channel (PDCCH) / enhanced PDCCH (EPDCCH), the UE performs or releases SPS transmission / reception. More specifically, even if SPS is assigned through RRC signaling, SPS transmission / reception is not immediately performed. Instead, in the case where an activation or release signal is received through a PDCCH / EPDCCH, after applying a modulation and coding rate according to the frequency resource (resource block) and modulation and demodulation scheme (MCS) information assigned by the corresponding PDCCH / EPDCCH, the UE performs SPS transmission / reception in a subframe corresponding to the subframe cyclic period and offset value assigned to the corresponding subframe through RRC signaling.

[0123] Hereinafter, SPS activation / release operations (related to WAN (VoIP( / UL)) communication) will be described in more detail.

[0124] The UE can verify a PDCCH for semi-static scheduling activation only when the following conditions are met.

[0125] 1) CRC parity bits obtained for the PDCCH payload should be scrambled by a semi-static scheduling C-RNTI, and 2) the "new data indicator" field should be set to "0".

[0126] The UE can verify an EPDCCH for semi-static scheduling activation only when the following conditions are met.

[0127] 1) The CRC parity bits obtained for the EPDCCH payload should be scrambled by the semi-static scheduling C-RNTI, and 2) the "new data indicator" field should be set to "0".

[0128] The UE can verify the semi-statically scheduled MPDCCH only when the following conditions are met.

[0129] 1) The CRC parity bits obtained for the MPDCCH payload should be scrambled by the semi-static scheduling C-RNTI, and 2) the "new data indicator" field should be set to "0".

[0130] The above verification is performed when all fields of the corresponding DCI format are configured as shown in the following table. Once the verification is achieved, the UE can consider the received DCI information as a valid semi-static activation / release. If the verification is not achieved, the received DCI format can be considered as received with an unmatched CRC.

[0131] [Table 1]

[0132]

[0133] Table 1 shown above shows an example of specific fields for PDCCH / EPDCCH verification for SPS activation.

[0134] [Table 2]

[0135]

[0136] Table 2 shown above shows an example of specific fields for PDCCH / EPDCCH verification for SPS release.

[0137] [Table 3]

[0138]

[0139] Table 3 shown above shows an example of specific fields for MPDCCH verification for SPS activation.

[0140] [Table 4]

[0141]

[0142] Table 4 shown above shows an example of specific fields for MPDCCH verification for SPS release.

[0143] In the case of activating downlink SPS under DCI format indication, the TPC field for PUCCH can be used to indicate one PUCCH resource value among the 4 PUCCH resource values configured by the higher layer. At this time, as shown in the following table, the mapping can be defined.

[0144] [Table 5]

[0145]

[0146] In the case of configuring multiple sidelink (SL) and / or uplink (UL) semi-static scheduling (SPS) processes / configurations (e.g., multiple SPS configurations / processes for uplink (and / or uplink + sidelink) (e.g., SPS configurations / processes for voice over Internet Protocol (VoIP), SPS configurations / processes for intelligent transportation systems (ITS))), the proposed method described in detail below presents a method for efficiently managing and operating these processes (e.g., SPS process / configuration activation / release, frequency resource reallocation, HARQ retransmission).

[0147] For example, the terms "sidelink SPS process / configuration" and "uplink SPS process / configuration" can each be interpreted as an SPS process / configuration for supporting "PC5-link-based V2X message transmission" and an SPS process / configuration for supporting "UU-link-based V2X message transmission" (and / or existing "WAN uplink ( / VOIP)" SPS process / configuration).

[0148] [Proposed Method #1] By configuring ( / signaling) different (new) "V2X_SPS-RNTI" (a part) for each "sidelink and / or uplink SPS process / configuration", independent management and operation (e.g., SPS process / configuration activation / release, frequency resource reallocation, HARQ retransmission) can be achieved for each "sidelink and / or uplink process / configuration".

[0149] For example, in the case of applying the corresponding rules, this can be interpreted as configuring ( / signaling) different "RNTI" values (a part) between multiple sidelink SPS processes / configurations (or uplink SPS processes / configurations) and / or configuring ( / signaling) different "RNTI" values (a part) between sidelink SPS processes / configurations and uplink SPS processes / configurations.

[0150] Here, as another example, it is also possible to configure (or signal) different (or common) "RNTI" values (a part thereof) between an existing (or traditional) WAN (VOIP ( / uplink)) communication-related SPS process ( / configuration) (e.g., "SPS C-RNTI") and a (V2X) uplink SPS process ( / configuration) (and / or sidelink SPS process ( / configuration)). Hereinafter, reference will be made to Figures 8 to 10 for a more detailed description thereof.

[0151] Figure 8 An example of an existing uplink SPS process is shown.

[0152] Referring to Figure 8 , the base station sends a high-layer signal (e.g., a radio resource control (RRC) signal) including the SPS cycle period to the UE (S801).

[0153] The base station may send, for example, an uplink SPS activation DCI for VoIP to the UE (which may be referred to as VoIP UL SPS activation DCI) (S802). The VoIP UL SPS activation DCI may include a cyclic redundancy check (CRC), and the CRC may be scrambled by using the SPS-C-RNTI (hereinafter referred to as the first RNTI).

[0154] The UE sends a signal to the base station at the SPS cycle period by using the resources configured according to the VoIP UL SPS activation DCI (S803).

[0155] The UE receives a DCI for releasing the VoIP UL SPS (which may be referred to as VoIP UL SPS release DCI) (S804). The VoIP UL SPS release DCI may also include a CRC, and the CRC may be scrambled by using the SPS-C-RNTI (the first RNTI).

[0156] The VoIP UL SPS activation DCI / VoIP UL SPS release DCI can be received through a physical downlink control channel (PDCCH) or an enhanced PDCCH (EPDCCH).

[0157] Figure 9 An example of the case where the uplink SPS process is applied to V2X is shown. Herein, the corresponding uplink SPS process will be referred to as the V2X uplink SPS process.

[0158] Referring to Figure 9 , the base station sends a high-layer signal (e.g., a radio resource control (RRC) signal) including the SPS cycle period to the UE (S901).

[0159] The base station may send, for example, uplink SPS activation DCI for V2X (which may be referred to as V2X UL SPS activation DCI) to the UE (S902). The V2X UL SPS activation DCI may include a cyclic redundancy check (CRC), and the CRC may be scrambled by using a V2X-SPS-RNTI (hereinafter referred to as the second RNTI). Herein, the second RNTI may correspond to another RNTI different from the above-mentioned first RNTI.

[0160] The UE sends a V2X signal to the base station at an SPS cycle period by using resources configured according to the V2X UL SPS activation DCI (S903).

[0161] The UE receives DCI for releasing V2X UL SPS (which may be referred to as V2X UL SPS release DCI) (S904). The V2X UL SPS release DCI may also include a CRC, and the CRC may be scrambled by using a V2X-SPS-RNTI (the second RNTI).

[0162] Figure 10 Illustrates a method for UE operation according to uplink SPS.

[0163] Refer to Figure 10 , the UE receives DCI indicating activation or release of uplink SPS (S210). The UE decodes the DCI based on the first RNTI or the second RNTI (S220). The first RNTI and the second RNTI have been described in detail with reference to Figure 8 and Figure 9 respectively. Figures 8 to 10 May correspond to an application example of [Proposed Method #1].

[0164] [Proposed Method #2] A single common (or shared) "V2X_SPS-RNTI" is configured ( / signaled) to multiple "sidelink (and / or uplink) SPS processes ( / configurations)", and this method can identify (or distinguish) which "sidelink (and / or uplink) SPS process ( / configuration)" the corresponding control information is related to by means of a (new) predefined ( / signaled) specific field within the "(sidelink (and / or uplink)-SPS)(activation / release) DCI" decoded by using the corresponding RNTI, where the specific field is, for example, a field notifying the "LCID" linked ( / interconnected) with the "(sidelink (and / or uplink) SPS process ( / configuration) index ( / ID))" and / or a "(sidelink (and / or uplink) SPS process ( / configuration) index ( / ID))" field (configured ( / signaled) by predefined signaling).

[0165] As a (one or more) field(s) for the above purposes, the "DM-RS CS (3-bit) field" can be (re-)used (e.g., in the case of (re-)using the existing "DCI format 0" type of "((VOIP) uplink (and / or side-link)-SPS)(activation / release) DCI" for the purpose of "(side-link (and / or (V2X) uplink)-SPS)(activation / release) DCI") and / or the "HARQ ID (3 / 4-bit) RV (2-bit) field" (e.g., in the case of (re-)using the existing "DCI format 1 / 1A / 2 / 2A / 2B / 2C / 2D" type of "((VOIP) uplink( / downlink) (and / or side-link)-SPS)(activation / release) DCI" for the purpose of "((V2X) side-link (and / or uplink)-SPS(activation / release) DCI").

[0166] In this document, for example, the size (X_size) of the field for the corresponding purpose can be fixed to a pre-configured ( / signaled) value (e.g., "3 bits"), and in the case where the maximum number (SPS_NUM) of "(side-link (and / or uplink) SPS processes ( / configurations)" configured ( / signaled) in the form of "carrier( / cell)-specific configuration" by the network (or (serving) cell) can vary (or change), the bits of "(X_size - ceiling(LOG2(SPS_NUM)))" (and / or "X_size - floor(LOG2(SPS_NUM))") can be processed by padding with zeros (or padding with a specific pre-configured ( / signaled) value) (e.g., this can be used for "virtual CRC") (in this document, for example, "ceiling(X)" and "floor(X)" can respectively indicate the function of taking the "smallest integer value greater than or equal to X" and the function of taking the "largest integer value less than or equal to X").

[0167] In this document, for example, in the case where a common "RNTI" value is configured ( / signaled) between an existing WAN (VOPI ( / uplink)) communication-related SPS process ( / configuration) and a (V2X) uplink SPS process ( / configuration) (and / or in the case of using "(activation / release) DCI" with the same (payload) size), the corresponding control information can be distinguished from which of the existing WAN (VOIP ( / uplink)) communication-related SPS process ( / configuration) and the (V2X) uplink SPS process ( / configuration) by a new field (e.g., "1" bit) predefined ( / signaled) and / or (reuse) of an existing field pre-specified ( / signaled) within the "(activation / release) DCI" decoded by using the corresponding common RNTI (which will be referred to as C_V2XARDCI hereinafter). For example, in the case of (re)using an "(activation / release) DCI" of the existing "DCI format 0" type, the "MCS / RV (5-bit) field (MSB (1 bit))" and / or the "TPC (2-bit) field (MSB (1 bit))" and / or the "CS DM RS (3-bit) field (MSB (1 bit))" can be (re)used).

[0168] In this document, for example, by defining a new field in C_V2XARDCI, in the case where the (payload) size becomes larger than that of the "(activation / release) DCI" related to the existing WAN (VOIP ( / uplink)) communication transmitted within the same user equipment (UE) specific search space (USS) ( / common search space (CSS)), in order to prevent an increase in the number of blind decoding sessions of the UE, padding with zero (or a specific pre-configured ( / signaled) value) can be performed (e.g., this can be used for "virtual CRC") until the WANARDCI (payload) size becomes equal to the (payload) size of C_V2XARDCI.

[0169] Figure 11 is a diagram showing a comparison between an existing (VoIP) uplink SPS activation / release DCI (first DCI) and a V2X uplink SPS activation / release DCI (second DCI) by applying [Proposed Method #2]. As described above with reference to Figure 8 and Figure 9 respectively, the first DCI can be CRC scrambled by SPS-C-RNTI (first RNTI), and the second DCI can be CRC scrambled by V2X-SPS-RNTI (second RNTI).

[0170] Referring to Figure 11, each of the first DCI and the second DCI includes a plurality of fields. The first DCI and the second DCI may include a plurality of common fields and a plurality of fields that are different from each other. For example, the first DCI and the second DCI may generally have a carrier indication field (0 bits or 3 bits), a resource block assignment and a hopping resource assignment field, an MCS and a redundancy version (RV) field, etc. In contrast, the first DCI may include a cyclic shift (CS) field corresponding to a demodulation reference signal (DM-RS) (which will be referred to as the DM-RS CS field hereinafter), while the second DCI may include an uplink SPS configuration index field instead of the DM-RS CS field.

[0171] According to the RNTI, if the DCI is CRC scrambled by the V2X-SPS-RNTI (the second RNTI), it may indicate that there is no DM-RS CS field (which refers to the above CS DM RS (3-bit) field) and there is an uplink SPS configuration index field. Alternatively, it may also indicate that in the first DCI, the DM-RS CS field is used for its original purpose (corresponding to notifying (or indicating) the cyclic shift of the DM-RS), and in the second DCI, the DM-RS CS field is used as the uplink SPS configuration index field.

[0172] Figure 12 An example of a method for interpreting specific fields when decoding the first DCI and the second DCI is shown.

[0173] Refer to Figure 12 , the UE receives a DCI (S310) indicating uplink SPS activation or release, and then, in the case of decoding the DCI based on the second RNTI, the DM-RS cyclic shift field of the DCI is interpreted as the UL SPS configuration index (S320).

[0174] As described above in [Proposed Method #2] and Figure 11 In the V2X uplink SPS activation / release DCI (the second DCI), the DM-RS cyclic shift field included in the existing uplink SPS activation / release DCI (the first DCI) may be interpreted as the UL SPS configuration index. As described above, this may also be expressed as including the UL SPS configuration index field in the V2X uplink SPS activation / release DCI (the second DCI), rather than the DM-RS cyclic shift field.

[0175] In the following, the DCI for scheduling the Physical Sidelink Control Channel (PSCCH) or Physical Sidelink Shared Channel (PSSCH) will be described in detail. The DCI for scheduling the (one or more) sidelink channels may include dynamic DCI (e.g., a method of scheduling only one transmission (using only one DCI)) and DCI based on the SPS method (e.g., a method of scheduling multiple transmissions (using only one DCI)), and more specifically, the DCI for activating / releasing sidelink SPS.

[0176] Figure 13 FIG. is a diagram showing a comparison between the DCI for dynamically scheduling a sidelink channel (DCI for dynamic scheduling (V2X SL dynamic DCI)) and the sidelink channel SPS activation / release DCI (V2X SL SPS activation / release DCI).

[0177] The total number of bits of each of the V2X SL dynamic DCI and the V2X SL SPS activation / release DCI may be configured differently. The V2X SL dynamic DCI and the V2X SL SPS activation / release DCI may include a common field, and the V2X SL SPS activation / release DCI may further include an additional field. More specifically, the V2X SL SPS activation / release DCI may have a larger total number of bits.

[0178] For example, the V2X SL dynamic DCI and the V2X SL SPS activation / release DCI may generally include a carrier indication field (3 bits), a field indicating the lowest index of the subchannel for initial transmission, a field indicating the frequency resource location, a field indicating the time gap between the initial transmission and the retransmission, etc.

[0179] Compared with the V2X SL dynamic DCI, the V2X SL SPS activation / release DCI may further include a sidelink SPS configuration index (3 bits) and a sidelink SPS activation / release field (1 bit).

[0180] Figure 14 FIG. shows an example of a method for transmitting downlink control information for sidelink scheduling according to another exemplary embodiment of the present invention.

[0181] Referring to Figure 14 , the wireless device generates a DCI (S410) indicating the activation or release of the V2X sidelink SPS, and then, the wireless device transmits the DCI (S420).

[0182] At this time, the DCI may further include a sidelink SPS configuration index (3 bits) and a V2X sidelink SPS activation / release field (1 bit) that are not included in the V2X sidelink dynamic DCI. More specifically, the V2X sidelink SPS activation / release DCI may have a larger total number of bits than the V2X sidelink dynamic DCI.

[0183] The sidelink SPS configuration index field may include information indicating at least one of a plurality of sidelink SPS configurations.

[0184] [Proposed Method #3] (For example, in the case where a single common "V2X_SPS-RNTI" and "(activation / release) DCI format" are used to manage and operate multiple "(sidelink and / or uplink SPS processes ( / configurations))",) the set of subframes (SFs) ( / cell sets) (and / or search space (SS) types (CSS / USS) and / or control channel (PDCCH / EPDCCH set) types) in which the relevant "(sidelink and / or uplink SPS) (activation / release) DCI" is received for each "(sidelink and / or uplink SPS process ( / configuration))" may be configured ( / signaled) differently (or independently).

[0185] For example, this operation may also be (limitedly) applied only to the case where multiple sidelink and / or uplink SPS transmissions are not performed in one subframe.

[0186] In the case of applying a part of the above proposed methods (e.g., [Proposed Method #1], [Proposed Method #2], [Proposed Method #3]), (A) differentiation (related to SPS process ( / configuration) activation / release, frequency resource reallocation, HARQ retransmission operation ( / instruction)) may be performed between multiple "(sidelink SPS processes ( / configurations))" (or "uplink SPS processes ( / configurations)"), and / or (B) differentiation (related to SPS process ( / configuration) activation / release, frequency resource reallocation, HARQ retransmission operation ( / instruction)) may be performed between "(sidelink SPS processes ( / configurations))" and "uplink SPS processes ( / configurations)".

[0187] For example, a single common "V2X_SPS-RNTI" may be configured ( / signaled) to multiple "(sidelink and / or uplink SPS processes ( / configurations))", and "activation / release" ( / frequency resource reallocation / HARQ retransmission) instructions related to multiple "(sidelink and / or uplink SPS processes ( / configurations))" may be simultaneously performed through one or more (new) predefined ( / signaled) specific fields within the "(sidelink and / or uplink - SPS) (activation / release) DCI" decoded by the corresponding RNTI.

[0188] For example, (A) in the case where (one or more) new specific fields can be implemented in bitmap form (e.g., in the case where it is possible to simultaneously handle (up to) "4" "sidelink and / or uplink SPS processes / configurations" by using "activation / release" ( / frequency resource reallocation / HARQ retransmission)), the corresponding fields can be implemented in the form of a bitmap ("WXYZ") with a length of "4 bits".

[0189] For example, in the bitmap, each of W, X, Y, and Z corresponds to 1 bit, and each bit is given a value of 0 or 1. In each bit, 0 / 1 can respectively indicate the activation / release of the corresponding sidelink and / or uplink SPS process / configuration. For example, W can indicate "activation / release of sidelink and / or uplink SPS process / configuration #0". X can indicate "activation / release of sidelink and / or uplink SPS process / configuration #1". Y can indicate "activation / release of sidelink and / or uplink SPS process / configuration #2". And Z can indicate "activation / release of sidelink and / or uplink SPS process / configuration #3". This can also be understood as the "sidelink and / or uplink SPS process / configuration index / ID" (information) linked / interconnected with the specific field values pre-configured / signaled in advance.

[0190] Alternatively, (B) (one or more) new specific fields can be implemented in a number of fields equal to the (maximum) number of sidelink and / or uplink SPS processes / configurations that can be simultaneously handled by using "activation / release" ( / frequency resource reallocation / HARQ retransmission). For example, in the case where it is possible to simultaneously "activate / release" (up to) "4" "sidelink and / or uplink SPS processes / configurations", and in the case where the "sidelink and / or uplink SPS process / configuration index / ID" is represented as "3 bits", the (one or more) corresponding fields can be implemented as "4" fields each having a length of "3 bits".

[0191] (According to the proposed method), in the case of simultaneously instructing (or indicating) "activation" ( / release / frequency resource reallocation / HARQ retransmission) related to multiple "sidelink and / or uplink SPS processes ( / configurations)", in order to reduce the conflict between "sidelink and / or uplink SPS processes ( / configurations)" with the same "cycle period value" and / or "frequency ( / time) resource position value" among the corresponding "sidelink and / or uplink SPS processes ( / configurations)" (simultaneously instructed (or indicated)), the "subframe offset" information of each "sidelink and / or uplink SPS process ( / configuration)" can be configured through the "subframe offset" information field of each "sidelink and / or uplink SPS process ( / configuration)" newly defined in (A) "higher layer signaling (e.g., "RRC")" or (B) "(sidelink and / or uplink - SPS)(activation / release) DCI".

[0192] In this document, for example, the "subframe gap (SF gap)" information applied between multiple "sidelink and / or uplink SPS processes ( / configurations)" (simultaneously indicated) can be configured ( / signaled) (e.g., in the case of simultaneously "activating" 2 "sidelink and / or uplink SPS processes ( / configurations)" with the same "cycle period value (P)" and "frequency ( / time) resource position value", (according to the ascending (or descending) order of the "sidelink and / or uplink SPS process ( / configuration) index ( / ID)"), the (periodic) resources related to "sidelink and / or uplink SPS process ( / configuration) #1" can be indicated in "SF#0, SF#P,..., SF#(N·P)" (or "SF#(0 + SF GAP), SF#(P + SF GAP),..., SF#(N·P + SF GAP)"), and the (periodic) resources related to "sidelink and / or uplink SPS process ( / configuration) #2" can be indicated in "SF#(0 + SFGAP), SF#(P + SF GAP),..., SF#(N·P + SF GAP)" (or in "SF#0, SF#P,..., SF#(N·P)"). In this document, SF indicates a subframe.

[0193] In this document, as another example, the "sidelink and / or uplink SPS processes ( / configurations)" processed by "activation" ( / release / frequency resource reallocation / HARQ retransmission) can be limited to those with different "cycle period values" and / or "frequency ( / time) resource position values".

[0194] For example, (A) in the case of using “activation” ( / release / reassignment of frequency resources / HARQ retransmission) to simultaneously process “sidelink and / or uplink SPS processes ( / configurations)” having the same “cycle period value” and / or “frequency ( / time) resource position value”, and / or (B) in the case of configuring ( / signaling) multiple “sidelink and / or uplink SPS processes ( / configurations)” having (partially) different “resource block size / position” and / or “cycle period value” and / or “MCS value”, etc., it is possible to announce (or notify) which “sidelink and / or uplink SPS process ( / configuration)” is valid in the current subframe (set) through predefined (higher layer / physical layer) signaling (e.g., “(sidelink and / or uplink - SPS)(activation / release) DCI”).

[0195] (Partially) different parameter (sets) (e.g., “resource block size / position”, “MCS value”) can be mapped ( / signaled) for each pre - configured ( / signaled) subframe set, and the corresponding parameter (set) can be applied to the “sidelink and / or uplink SPS process ( / configuration)” that is valid ( / “on”) (or is used) within the specific subframe set.

[0196] Alternatively, (different from the proposed method above) in the case where (one or more) “sidelink and / or uplink SPS process (configuration) index ( / ID)” fields are not defined in the “(sidelink and / or uplink - SPS)(activation / release) DCI” and the periodic resources related to the “sidelink and / or uplink SPS process ( / configuration) #X” are indicated at the time point “SF#N”, the “(sidelink and / or uplink - SPS) release ( / reassignment of frequency resources / HARQ retransmission) DCI” received at the time point “SF#(N - K)” (e.g., “K = 4”) can be regarded as ( / assumed to) implicitly indicate the DCI for the “release ( / reassignment of frequency resources / HARQ retransmission)” of the corresponding “sidelink and / or uplink SPS process ( / configuration) #X”.

[0197] For example, (A) the “mode 1 DCI” that announces (or notifies) the (PSCCH and / or PSSCH) scheduling information related to sidelink (and / or uplink) SPS (e.g., V2X SL (and / or uplink) SPS activation / release DCI) can be composed of (a part of) the following fields. And / or, (B) the “K” - time (repeated) re - transmission operations related to the same transport block (TB) can be defined to be performed according to (a part of) the following rules.

[0198] It is possible to attempt to perform decoding of "Mode 1 DCI" using a "(separately configured ( / signaled))" "RNTI" that is different (or the same) from the "(SideLink and / or UL-SPS) (activation / release) DCI" (described above).

[0199] One or more fields (a part of) within "Mode 1 DCI" (such as at least one of (Example #1-1), (Example #1-2), (Example #1-3), (Example #1-5), and (Example #1-6) described below) can be reconfigured as ( / used as) a field ( / fields) of "Schedule Assignment ( / PSCCH)".

[0200] Type of field configuring "Mode 1 DCI"

[0201] (Example #1-1) "(SideLink and / or UL SPS process ( / configuration) index ( / ID))" field.

[0202] (Example #1-2) "Timing gap" (indication) field between "Data ( / PSSCH)" interconnected with "Schedule Assignment ( / PSCCH)" (and / or interval (indication) field between "Resource (re) selection trigger timing" and "Schedule Assignment ( / PSCCH) transmission timing"). Here, for example, when operating in "Mode 1", the corresponding field value can be fixed to a predefined ( / signaled) specific value (such as "Timing gap = 0"), and in this case, the corresponding field can also be omitted.

[0203] (Example #1-3) "(Retransmission count counter ( / indicator) (related to the same transport block (TB)))" field (and / or "(Redundancy version (RV) (related to the same TB))" field). Here, for example, the corresponding field can be (only) available specifically when "Mode 1 DCI" (and / or "SA ( / PSCCH)") is sent together (or collectively) during each retransmission related to the same TB.

[0204] (Example #1-4) "SA ( / PSCCH)" related frequency ( / time) resource information field.

[0205] (Example #1-5) "Data ( / PSSCH)" related frequency ( / time) resource information field.

[0206] (Example #1-6) “SA( / PSCCH)” and / or “data( / PSSCH)” related “Transmission Power Control (TPC) command” field (e.g., when the size of the corresponding “TPC command” field is equal to “1 bit”, a “0” value may indicate “apply a pre-configured ( / signaled) (maximum) transmission power value (i.e., “non-open loop power control”), and a “1” value may indicate “determine the transmission power value according to a predefined “open loop power control” formula”) and / or a field for notifying (or informing) whether to apply “data( / PSSCH)” related “frequency hopping” and / or “data( / PSSCH)” related “Time Resource Pattern (T-RPT)” field.

[0207] (Example #1-7) An indicator field related to “sidelink and / or uplink SPS process ( / configuration) activation ( / release)”.

[0208] (Example #1-8) An information field related to a time period (e.g., “subframe” unit) of a predetermined length ( / size) during which resources related to “sidelink and / or uplink SPS process ( / configuration)” are maintained (or an information field indicating the number of cycles of “sidelink and / or uplink SPS process ( / configuration)” during which the corresponding resources are maintained). This field may be interpreted as “activation duration timer” information.

[0209] Upon receiving the above “Mode 1 DCI”, the rules for “K” (repeated) retransmission operations related to the same transport block (TB) can be determined by at least one of the following examples.

[0210] (Example #2-1) When “Mode 1 DCI” (and / or “SA( / PSCCH)”) is sent together (or collectively) during each retransmission ( / initial transmission) related to the same TB, the retransmission ( / initial transmission) can be performed according to the scheduling information of (“SA( / PSCCH)” and / or “data( / PSSCH)”) notified ( / indicated) by the above fields within the corresponding “Mode 1 DCI” (e.g., (Example #1-1)( / (Example #1-2), (Example #1-3), (Example #1-4), (Example #1-5), etc.).

[0211] (Example #2-2) To perform “K” (repeated) retransmissions related to the same TB, in the case of transmitting only one “Pattern 1 DCI” (and / or “SA( / PSCCH)”) related to the initial transmission scheduling, (A) it can be assumed that the (”data( / PSSCH)”) retransmissions are performed within consecutive subframes by using the same frequency resources as the initial transmission, or (B) the time resource pattern (T-RPT) information related to the (”data( / PSSCH)”) retransmission ( / initial transmission) can be announced (or notified) within one “Pattern 1 DCI” (and / or “SA( / PSCCH)”) related to the initial transmission scheduling. For example, in the case of (B), it can be assumed that the frequency resources related to the retransmission are the same as those of the initial transmission.

[0212] Figure 15 An example of a method for performing SPS processing according to another exemplary embodiment of the present invention is shown.

[0213] Referring to Figure 15 , the wireless device determines the priority corresponding to each of the plurality of SPS processes (S510), and can configure the SPS-related parameters differently according to the priority of each SPS process (S520). The SPS process may correspond to an SPS process ( / configuration) corresponding to the sidelink and / or an SPS process ( / configuration) corresponding to the uplink. The SPS-related parameters may include, for example, at least one of first information, second information, third information, and fourth information. The first information announces the fixed time gap between the data scheduled by the sidelink control information and the sidelink control information. The second information announces the fixed time gap between the time point when resource selection is triggered and the sidelink control information. The third information announces the sensing window size corresponding to the segment for which sensing is to be performed for resource selection therebetween. The fourth information is related to the open-loop transmission power.

[0214] More specifically, in the case of configuring ( / signaling) a plurality of “sidelink and / or uplink SPS processes ( / configurations)”, for example, the value of the “fixed time gap” between the “data( / PSSCH)” interconnected with the “SA( / PSCCH)” for each “sidelink and / or uplink SPS process ( / configuration) (set)” can be configured ( / signaled) differently (and / or the interval (or gap) between the “resource (re)selection trigger timing” and the “SA( / PSCCH) transmission timing” and / or the “sensing window size” (based on SA decoding / energy measurement) and / or the “(open-loop) transmission power parameter”). Therefore, the parameter levels between the “sidelink and / or uplink SPS process ( / configuration) (sets)” can be specified differently (implicitly).

[0215] For example, by configuring ( / signaling) a "timing gap" (and / or the interval (or gap) between "resource (re) - selection trigger timing" and "SA ( / PSCCH) transmission timing" and / or the "sensing window size (based on SA decoding / energy measurement)") with a relatively large value (or small value) within a "sidelink and / or uplink SPS process ( / configuration) (set)" having a relatively high priority, and by configuring ( / signaling) a "sidelink and / or uplink SPS process ( / configuration) (set)" with a relatively low priority (i.e., a "timing gap" (and / or the interval (or gap) between "resource (re) - selection trigger timing" and "SA ( / PSCCH) transmission timing" and / or the "sensing window size (based on SA decoding / energy measurement)") with a relatively small value (or large value)), a V2X UE performing V2X communication can (with high probability) detect ( / sense) an "SA ( / PSCCH)" with a relatively high priority, and can also select ( / schedule) its own "data ( / PSSCH)" resources while (as much as possible) avoiding the "data ( / PSSCH)" being scheduled by the corresponding "SA ( / PSCCH)".

[0216] A "(one or more) (open - loop) transmission power parameter" (such as "P_O" and / or "ALPHA", etc.) with a relatively large value can be configured ( / signaled) within a "sidelink and / or uplink SPS process ( / configuration) (set)" having a relatively high priority. Herein, for example, a "sidelink and / or uplink SPS process ( / configuration) (set)" with a relatively high priority can be used ( / assigned) for an "event - triggered V2X message transmission ( / service type)" and / or a "service type requiring relatively high reliability".

[0217] More specifically, the first information, second information, and third information corresponding to an SPS process with a relatively high priority among multiple SPS processes can be configured to have a larger value (or smaller value) than the first information, second information, and third information corresponding to an SPS process with a relatively low priority.

[0218] In addition, among multiple SPS processes, a fourth information corresponding to an SPS process with a relatively high priority can be configured to have a larger value (or smaller value) than the fourth information corresponding to an SPS process with a relatively low priority.

[0219] Among multiple SPS processes, an SPS process with a relatively high priority can be used for event - triggered vehicle - to - everything (V2X) message transmission.

[0220] Among multiple SPS processes, an SPS process with a relatively high priority can be used for a service type requiring relatively high reliability.

[0221] In the case of a predefined event occurring (e.g., in the case of a speed / travel direction / position change (or alteration) that is equal to or greater than a predefined (signaled) threshold compared to a previous time point when "V2X message transmission" has been performed), a "V2X message (e.g., "CAM" generation (transmission))" can be (immediately) triggered. Accordingly, the "cycle period" and / or "size change pattern" (and / or the interval between consecutive "V2X message generation (transmission)") etc. related to "V2X message generation (transmission)" can be changed (or varied) (in the time domain).

[0222] When considering this problem (phenomenon), it may be difficult for a V2X UE to perform "V2X message transmission" with high "reliability" (and / or meet the "latency requirement") through a specific cycle period and / or time / frequency resource size and / or MCS of a "single SPS configuration / process" configured (signaled) by a base station. To solve this problem, the cycle period related to the "single SPS configuration (process)" can be configured to be (extremely) short and large-sized (time / frequency) resources can be assigned. However, in terms of efficient resource management, this method is not preferred.

[0223] As a solution, a base station can configure (signal) "multiple SPS configurations (processes)" (with different cycle periods and / or (time / frequency) resource sizes (and / or MCS)) for a V2X UE, and then, the base station can also allow the V2X UE to report a part of the following information.

[0224] The information reporting can be performed through a predefined (signaled) channel (e.g., "PUSCH (PUCCH)", "SR"). The base station that has received (been reported) this information can "release" ("deactivate") the "SPS configuration (process)" that is not used by the corresponding V2X UE (or is (most) unsuitable for the corresponding V2X UE), or the corresponding base station can newly configure (signal) the (most) suitable "SPS configuration (process)" (or the (time / frequency) resource size (and / or MCS) and / or cycle period related to the (existing) "SPS configuration (process)") for the corresponding V2X UE.

[0225] As another example, the base station that has received (been reported) this information can (eventually) instruct the corresponding V2X UE to perform a handover to the (most) suitable "SPS configuration (process)" among the "multiple SPS configurations (processes)".

[0226] In this document, for example, the corresponding handover instruction can be executed via a predefined ( / signaled) channel (e.g., “(E)PDCCH( / PDSCH)”). In this document, for example, this rule can be applied only limitedly to V2X communication based on “Mode 1 (i.e., the method by which the base station controls ( / signals) scheduling information related to “V2X message transmission”)” and / or “RRC_connected V2X UE ( / V2X UE within the cell coverage).

[0227] The V2X UE can report at least one of the following information.

[0228] (Example #A) “SPS configuration ( / process) (index / ID) information” of the configured ( / signaled) “multiple SPS configurations ( / processes)” that is used by (or (most) suitable for) the corresponding V2X UE and / or that is not used by (or (most) unsuitable for) the corresponding V2X UE.

[0229] (Example #B) “Utilization information” and / or “collision detection information” and / or “interference ( / energy) measurement information” and / or “timing misalignment” information between the time points ( / cycle periods) at which the (current) “V2X message transmission ( / generation)” of each of the configured ( / signaled) “multiple SPS configurations ( / processes)” is misaligned (e.g., this can also be interpreted as the (estimated) cycle period / offset information of the (current) “V2X message transmission ( / generation)” time point ( / cycle period) that is suitable for the corresponding V2X UE).

[0230] As another example, a V2X UE configured ( / signaled) by the base station with “multiple SPS configurations ( / processes)” having different cycle periods and / or (time / frequency) resource sizes (and / or MCS) can select / use the SPS configuration ( / process) that is most suitable for the corresponding V2X UE, and the V2X UE can report the corresponding result (e.g., the “SPS configuration ( / process) (index / ID) information” selected / used by the V2X UE) to the base station.

[0231] Hereinafter, methods for efficiently supporting sidelink SPS operations and uplink SPS operations related to V2X communication, such as methods for configuring DCI format fields, will be described in detail.

[0232] First, the sidelink SPS operation will be described in detail.

[0233] In the case of mode 1 SPS, the base station can configure several (multiple) SPS configurations for the UE. The MCS specific to the SPS configuration and the cycle period specific to the SPS configuration can be configured. The base station can use PDCCH / EPDCCH to dynamically trigger / release different SPS configurations. Before the transmission time point associated with the SPS configuration, the UE can notify the base station that the UE will not perform data transmission.

[0234] For V2V, mode 1 can support cross-carrier scheduling and dynamic scheduling for sidelink SPS.

[0235] Below, multiple SPS configurations will be described in detail.

[0236] In PC 5-based mode 1 SPS, the base station can configure multiple SPS configurations. The parameters in each SPS configuration can be predetermined (or determined in advance) by the higher layer signal. For example, the SPS offset can vary according to the SPS configuration, and the exact mapping between the index of each SPS configuration and the SPS offset value can be defined by the RRC signal.

[0237] The UE can request the desired SPS configuration, and the base station can activate the SPS configuration according to the request made by the UE. The configuration index of the SPS configuration can be transmitted through the SPS trigger message, and thus, the desired SPS configuration can be verified. If the UE can manage and operate only one SPS configuration at a time, the configuration index of the SPS configuration can be converted into digits. For example, if there are a total of 8 SPS configurations, the configuration index of the activated or to-be-activated configuration can be notified by 3 bits, and then this configuration index can be transmitted through the SPS trigger message.

[0238] On the contrary, if the UE can manage and operate multiple SPS configurations simultaneously, the indexes corresponding to the multiple SPS configurations can be represented in the form of a bitmap. For example, if there are a total of 8 SPS configurations, the configuration index of the activated or to-be-activated configuration can be notified by an 8-bit bitmap, and then this configuration index can be transmitted through the SPS trigger message.

[0239] After triggering or releasing the sidelink SPS configuration, if the base station does not monitor the sidelink message, the base station cannot confirm whether the UE has actually performed the SPS message transmission or whether the UE has suspended the transmission, etc. Therefore, the UE can feedback the ACK / NACK corresponding to whether the UE has correctly received the sidelink SPS trigger / release message.

[0240] <(E)PDCCH for sidelink SPS>

[0241] The DCI for sidelink SPS can be sent via PDCCH or EPDCCH. This DCI can be referred to as DCI format 5. DCI format 5 can include at least one of the following fields.

[0242] Resource indication field for PSCCH. It can be determined that this field has a size of 6 bits.

[0243] TPC command for PSCCH and PSSCH. It can be determined that this field has a size of 1 bit.

[0244] Hopping flag (1 bit), resource block assignment, and hopping resource assignment fields (depending on the bandwidth, it can be determined that this field has a size of any one of 5 bits to 13 bits). Time resource pattern (7 bits).

[0245] If the number of information bits included in DCI format 5 mapped to a given search space is less than the payload size of DCI format 0 scheduling the same serving cell, a value of 0 (zero) can be appended to DCI format 5 so that the payload size can be the same as that of DCI format 0 (zero padding). In this case, the number of bits of the appended 0 (zero) value, that is, the number of zero-padding bits, can be equal to 0, or can be equal to a different value other than 0. When considering this characteristic, it is not preferred to use zero-padding bits as a new field. More specifically, in order to use a new field such as an SPS configuration index for DCI format, it may be necessary to change a part (or some) of the existing fields. Most specifically, this can correspond to the case of reusing an existing DCI format (such as DCI format 5).

[0246] Considering the complexity of SPS configuration detection (blind decoding) and the aspect of saving (E)PDCCH resources, the following two methods can be considered.

[0247] 1) Method of using different RNTIs for each SPS configuration. According to this method, no additional (or additionally appended) DCI bits are required.

[0248] 2) Method of using the same RNTI while adopting the "SPS configuration index" field.

[0249] In the method where the DCI bit is not added, a specific RNTI can be assigned to each SPS configuration. For example, different RNTIs such as SL SPS C-RNTI 0, SL SPS C-RNTI 1,... can be assigned to the SPS configuration. In this case, an overly large number of RNTIs may be required, and the UE may be required to perform a large number of blind decoding sessions to detect the SPS trigger / release message. Therefore, it may be preferable to perform method 2) rather than method 1). More specifically, it may be preferable that each SPS configuration uses a common RNTI and each SPS configuration includes a field indicating which SPS configuration the trigger / release corresponds to.

[0250] The SPS configuration field can be represented as an index of the SPS configuration. For example, in the case where there are 7 SPS configurations, the size of the SPS configuration field can be equal to 3 bits. The SPS configuration field can also be represented in the form of a bitmap. In the example shown above, the SPS configuration field can be represented as a 7-bit bitmap. In this case, managing and operating multiple SPS configurations simultaneously is sufficient for performing the indication (or instruction).

[0251] Hereinafter, the cross-carrier scheduling and dynamic scheduling of the sidelink SPS for V2V in mode 1 will be described in detail. Preferably, the (E)PDCCH design for the sidelink SPS is compatible with the sidelink dynamic scheduling. One way to achieve this is to include an indication field indicating whether the design is for dynamic scheduling or for SPS scheduling. A more resource-saving method corresponds to distinguishing the scheduling mode through the SPS configuration field itself. For example, when the value of the SPS configuration field is equal to '000', this can indicate dynamic scheduling or a single transmission (e.g., one TB transmission). Other values can be matched with SPS configuration 0 to SPS configuration 7 respectively.

[0252] In the case of dynamic scheduling, after transmitting a transport block (TB), the sidelink resources assigned by the base station are automatically released. Other operations can be the same as the sidelink SPS operations. Which specific value (status) of the SPS configuration field indicates the dynamic scheduling mode and / or the SPS scheduling mode can be signaled in advance by the base station through a higher-layer signal or predetermined (this can be determined in the standard specification).

[0253] Figure 16 Describe an example of verifying the DCI as the DCI format for V2X sidelink SPS activation / release or the V2X sidelink dynamic DCI.

[0254] The DCI format for V2X sidelink SPS activation / release and the V2X sidelink dynamic DCI may include at least one or more common fields. Additionally, the DCI format for V2X sidelink SPS activation / release may further include fields not included in the V2X sidelink dynamic DCI (e.g., the SPS configuration index field).

[0255] Among the fields included in the DCI format, when each of the predetermined specific fields has a predetermined value (sequence), the UE may verify the corresponding DCI format as the DCI format for V2X sidelink SPS activation / release.

[0256] For example, in the case of SPS release, since no actual SPS data transmission occurs, the values of the DCI fields related to resource allocation (MCS, RV, resource block allocation field, etc.) become unnecessary (or redundant) values. Therefore, the values of the DCI fields related to resource allocation may be configured as a predetermined sequence (e.g., all values may be set to 0).

[0257] The following table shows an example of the mapping between the cyclic shift DM-RS field and the V2X uplink SPS configuration index.

[0258] [Table 6]

[0259] Value of the SPS configuration field of the sidelink (E)PDCCH Use "000” Sidelink dynamic scheduling "001” Sidelink SPS configuration 0 for V2X "010” Sidelink SPS configuration 1 for V2X "011” Sidelink SPS configuration 2 for V2X "100” Sidelink SPS configuration 3 for V2X "101” Sidelink SPS configuration 4 for V2X "110” Sidelink SPS configuration 5 for V2X "111” Sidelink SPS configuration 6 for V2X

[0260] To save DCI fields in DCI format 5, there may be some flexibility in resource allocation for SPS. To schedule the indicated sidelink V2V (including SPS), the number of bits of the DCI field may be reduced according to the positional correlation between the SA and the data. When sending SPS data in the T-RPT mode, the T-RPT field, the frequency hopping flag field, and / or the RV field may be used. However, when each SPS (re)transmission follows the DCI, this DCI field may not be required.

[0261] If the time gap between SA transmission and data transmission is notified in advance or fixed, the time indication field corresponding to the data transmission (the field notifying the timing offset between the announced (or notified) SA and the data) will not be required. Additionally, if the SA can announce (or notify) the start position of the frequency allocation of the data, the resource block allocation field included in the DCI may be sufficient to only notify the RB size of the corresponding data. Therefore, the resource block allocation field may be reduced to 3 to 7 bits.

[0262] Similarly, by performing sub-channelization of the data region, more DCI bits can be saved. For example, by dividing (or sub-channelizing) the data region into 10 sub-channels, the resource block allocation field may be reduced to 4 bits.

[0263] The following shows an example of changing the fields (DCI fields) included in DCI format 5 for sidelink SPS.

[0264] [Table 7]

[0265]

[0266] DCIs including different SP configurations can be associated with a common RNTI, and the corresponding RNTI can be different from the RNTI used for dynamic scheduling.

[0267] DCI format 5 can undergo minor changes and then can be used for (E)PDCCH for sidelink SPS triggering / release.

[0268] Depending on the relationship between the time / frequency position of the SA and the data, the resource block assignment field and the T-RPT field for DCI format 5 can be excluded or their lengths can be reduced.

[0269] In summary, 1) after receiving an (E)PDCCH message for SPS triggering / release, the UE can feedback ACK / NACK. 2) DCIs with different SP configurations can be associated with a common RNTI, and from the UE's perspective, the corresponding RNTI can be different from the RNTI used for dynamic scheduling. 3) DCI format 5 can undergo minor changes and then can be used for (E)PDCCH for sidelink SPS triggering / release. 4) Depending on the relationship between the time / frequency position of the SA and the data, the resource block assignment field and the T-RPT field can be excluded or their lengths can be reduced.

[0270] In the following, methods for efficiently supporting uplink SPS operations will be described in detail.

[0271] As described above, in the case of mode 1 SPS, the base station can configure several (multiple) SPS configurations for the UE. The MCS specific to the SPS configuration and the cyclic period specific to the SPS configuration can be configured. The base station can use PDCCH / EPDCCH to dynamically trigger / release different SPS configurations. Before the transmission time point associated with the SPS configuration, the UE can notify the base station that the UE will not perform data transmission.

[0272] <(E)PDCCH Design for Uplink SPS>

[0273] Uplink SPS and sidelink SPS are similar in that they are both related to V2X message transmission and the base station configures resources. Therefore, preferably, uplink SPS and sidelink SPS have the same design.

[0274] In the uplink SPS (E)PDCCH design, the DCI used for UL grant (e.g., DCI format 0) can become the basic DCI. Considering the characteristics of SPS, the uplink SPS (E)PDCCH should distinguish its SPS triggering / release. In addition, multiple SPS configurations should be supported. For this purpose, it may be necessary to change some (or a part) of the fields included in the existing DCI format, and then adopt a new field (SPS configuration index). In this article, the SPS configuration field can be represented as an index of the SPS configuration. For example, the SPS configuration field can be represented as an index of the SPS configuration. For example, in the case of 7 SPS configurations, the size of the SPS configuration field can be equal to 3 bits.

[0275] If the cyclic shift DM RS field is used as the SPS configuration index, each of the remaining values except "000" can match SPS configurations 0 to 7. Except for the cyclic shift DM RS field, the execution of V2X uplink SPS triggering / release can be similar to that of LTE uplink SPS.

[0276] The following table shows an exemplary mapping between the values of the cyclic shift DM RS field and the values of the V2X uplink SPS configuration index.

[0277] [Table 8]

[0278]

[0279] The SPS configuration field can also be represented as a bitmap (e.g., an 8-bit bitmap). This case is preferred for the synchronization management and operation of multiple SPS configurations.

[0280] <Handling conflicts between different SPS configurations>

[0281] In the uplink SPS, how to handle the change of the message arrival pattern may be an important issue. First, if the message arrival pattern changes, the UE can inform (or notify) the base station of this change so that appropriate actions can be taken.

[0282] The UE can inform the base station that the UE will not send any data before the transmission time point associated with the SPS configuration. The UE can inform that it will not send any data during an SPS transmission opportunity, or the UE can inform that it will not send any data during all SPS transmission opportunities (i.e., a relatively long period according to the SPS configuration).

[0283] In the latter case, the UE report can be regarded as an SPS configuration change / release request. More specifically, in the case where the message arrival pattern changes because the UE does not use a specific SPS configuration during a specific period, the UE can report this situation to the base station so that the base station can activate another SPS configuration suitable for the changed message arrival pattern. This report can be provided through a high-layer signal to prevent excessive uplink overhead.

[0284] In the former case, the UE report can be regarded as a "verification of a single transmission opportunity". The base station can know which SPS transmission opportunity the UE is actually using.

[0285] This verification can correspond to a positive verification or a negative verification. In the case where the verification corresponds to a positive verification, when the UE sends data, the corresponding report is sent, and if there is no positive verification, it can be interpreted that no data is sent. In this case, the corresponding resources can be used for other purposes.

[0286] In the case where the verification corresponds to a negative verification, the corresponding report is sent when the UE does not send any data. Among these two verification methods, it may be preferable to use the positive verification method. This is because the corresponding report can reduce the number of transmission sessions performed for sending the report. The advantage of positive verification is that the number of verification messages transmitted is not greater than the actual SPS data transmission.

[0287] Most specifically, in the case where multiple SPS configurations are configured for the UE, this advantage becomes clearer. For example, in order to handle a change in message size, if negative verification is used, the UE will be required to send a negative verification before each of the unused SPS transmission opportunities. On the contrary, if positive verification indicates the actually used SPS configuration, it can be generalized that positive verification selects the SPS configuration during each data transmission. For example, PUCCH resources can be assigned to the UE, and the index of the SPS configuration to be used during the next data transmission can be included in the PUCCH transmission.

[0288] Figure 17An example of using 2 reports simultaneously is shown. The UE can be configured with 3 cycle periods, i.e., 1000 ms, 500 ms, and 100 ms with different SPS configurations. The UE can first be instructed to activate SPS configuration #1. If the message generation cycle period becomes 100 ms, the UE can report a change request to the base station, and the base station can release SPS configuration #1. Thereafter, the base station can activate SPS configuration #3. Thus, the message generation cycle period can become 500 ms. The UE can have data scheduled to be sent during several SPS transmission opportunities. At this time, although the verification can correspond to a positive verification, the data is not sent. When the UE recognizes this situation, the UE can report another change request to the base station, and the base station can then activate SPS configuration #2.

[0289] Compared with other uplink transmissions, the reports related to sidelink transmissions can have a lower priority. For example, if the UE schedules ACK / NACK transmissions or PUSCH transmissions, the verification of SPS transmissions can be discarded.

[0290] Since the base station can know when the UE sends the verification, the base station can prevent the verification from being discarded due to scheduling. If the transmission of the verification is discarded due to the scheduling of the base station, in order to avoid violating (or not violating) the latency requirements, the UE can send the data during the corresponding SPS transmission opportunity. When the base station is informed (or learns) that the verification transmission has been discarded, the base station can not use the corresponding SPS resources for other purposes.

[0291] Meanwhile, when performing V2X mode 1 communication, a method that allows the V2X transmitting UE to determine the (V2X data transmission related) MCS value as implemented by the UE (or independently determine this MCS value) can be supported.

[0292] In this article, for example, in the case where the same DCI format (or DCI format with the same configuration) (e.g., a role similar to the (existing) "DCI format 5") (which will be referred to as mode 1_DCI) is used for scheduling V2X mode 1 communication based on the "dynamic format" and / or "SPS format", the MCS field can be defined.

[0293] For example, if the MCS field value in the mode 1_DCI received from the (serving) base station indicates a pre-configured ( / signaled) specific value (or "reserved state"), the V2X UE can determine the (V2X data transmission related) MCS value as implemented by the UE (or independently determine this MCS value) (e.g., if the MCS field value in the mode 1_DCI indicates another value (other than the values mentioned above), the V2X data transmission can be performed according to the corresponding MCS value).

[0294] For example, a field may be defined (additionally) to indicate a "cyclic shift (CS) index" value (and / or a seed value related to sequence generation, such as a sequence group number (U), a basic sequence number (V)) related to PSSCH( / PSCCH) DM-RS (sequences) within a DCI format related to V2X mode 1 communication scheduling.

[0295] For example, instead of defining (additionally) Mode1_CSFD within a DCI format related to V2X mode 1 communication scheduling, (A) if a "cyclic shift (CS) index" value (and / or a seed value related to sequence generation) related to PSSCH( / PSCCH) DM-RS (sequences) is received from a (serving) base station via RRC signaling, the V2X transmitting UE can generate PSSCH( / PSCCH) DM-RS (sequences) according to the corresponding value.

[0296] (B) Alternatively, if a "cyclic shift (CS) index" value (and / or a seed value related to sequence generation) related to PSSCH( / PSCCH) DM-RS (sequences) is not received from a (serving) base station (via RRC signaling), the V2X transmitting UE can determine the "cyclic shift (CS) index" value (and / or a seed value related to sequence generation) related to PSSCH( / PSCCH) DM-RS (sequences) as the UE implementation (or independently determine the value).

[0297] For example, the type ( / range) of "cyclic shift (CS) index" values (and / or seed values related to sequence generation) that can be determined as the UE implementation (or independently determined) can be preconfigured ( / signaled).

[0298] The "cyclic shift (CS) index" value (and / or a seed value related to sequence generation) related to PSSCH DM-RS (sequences) determined according to the above rules can also be signaled through a (specific) field within SA (for example, a role similar to the existing "SCI format 0").

[0299] For example, the (mode 1) PSSCH( / PSCCH) DM-RS (sequence) ("cyclic shift (CS) index" value) can be generated ( / determined) by a function that defines an RNTI (SPS-RNTI) value related to V2X mode 1 communication based on an "SPS format" (and / or an RNTI (DYM-RNTI) value related to V2X mode 1 communication based on a "dynamic format") to be reconfigured ( / signaled) as input parameters, and the function is, for example, "FLOOR(SPS-RNTI / 2) MOD 8" (herein, "FLOOR(X)" and "A MOD B" respectively indicate a function to take an integer equal to or less than X and a function to take the remainder obtained by dividing A by B).

[0300] In the case where a V2X UE performing V2X mode 1 communication based on the "SPS format" has received the configuration ( / signaling) of (time / frequency) resources such that the corresponding V2X UE can perform (TMD) transmissions of PSCCH and PSSCH more than W and Q times respectively, (A) if the pre-configured ( / signaled) S-th (e.g., "S = 1") PSCCH transmission is performed and the (predefined) SPS release DCI format (which will be referred to as SPS_RELFMT) is received before the interconnected PSSCH transmission (in subframe #N) (and / or if SPS_RELFMT is received when performing the (PSCCH / PSSCH) transmission operation related to a (specific) transport block (in subframe #N)), then it can be set (based on the assumption that the SPS resources have been released after a time point including (or not including) subframe #(N + 4)) such that subsequent transmission operations are not performed (by the corresponding SPS resources) (or it can be set such that only the transmission related to the (specific) transport block can be performed ( / completed)).

[0301] In this document, for example, in order to release the pre-configured ( / signaled) (mode 1) SPS resources and / or suspend the (PSCCH / PSSCH) transmission operation based on the corresponding (SPS) resources, it can be set such that SPS_RELFMT can be received before the pre-configured ( / signaled) value (e.g., "4 ms") from the (at least) first PSCCH transmission point related to a (specific) transport block.

[0302] In the case where a V2X UE performing V2X mode 1 communication based on the "dynamic format" has received the configuration ( / signaling) of (time / frequency) resources within multiple subframes for transmitting a (specific) transport block, if the DCI format (DYN_RELFMT) indicating that the (predefined) dynamic transmission is suspended is received when performing the (PSCCH / PSSCH) transmission operation related to the (specific) transport block (in subframe #J), then it can be set (based on the assumption that the dynamic resources are invalid (or effective) after a time point including (or not including) subframe #(J + 4)) such that subsequent transmission operations are not performed (or it can be set such that only the transmission related to the (specific) transport block can be performed ( / completed)).

[0303] In this document, for example, in order to invalidate (release) the pre-configured ( / signaled) (mode 1) dynamic resources and / or suspend the (PSCCH / PSSCH) transmission operation based on the corresponding (dynamic) resources, it can be set such that DYN_RELFMT can be received before the pre-configured ( / signaled) value (e.g., "4 ms") from the (at least) first PSCCH transmission point related to a (specific) transport block

[0304] For example, in a case where the V2X UE has received configuration ( / signaling) from its (serving) base station ( / cell) indicating that the V2X UE shall prioritize GNSS timing ( / synchronization) over base station timing ( / synchronization) within a specific carrier, if another base station ( / cell) is detected within the corresponding (specific) carrier (e.g., this can be understood as the V2X UE being within the coverage area of the detected other base station ( / cell)), and if the corresponding other base station ( / cell) is transmitting configuration ( / signaling) indicating that the UE shall prioritize base station timing ( / synchronization), then (if the V2X UE is (at least) within the coverage area of the detected other base station ( / cell)), the V2X UE may prioritize base station timing ( / synchronization).

[0305] The V2X UE may also receive from its (serving) base station ( / cell) configuration ( / signaling) indicating which base station ( / cell) within a specific carrier the base station timing ( / synchronization) or GNSS timing ( / synchronization) shall be prioritized for.

[0306] In a case where HARQ-ACK feedback corresponding to the reception of "sidelink (and / or uplink)-SPS (activation / release) DCI" is defined, in the case of "NACK", the V2X UE is capable of performing mode 2 (fallback) operation (based on an (excluded) pool) during a preconfigured ( / signaled) period.

[0307] In a case where multiple "sidelink (and / or uplink) SPS processes ( / configurations)" are configured ( / signaled) (for a specific V2X UE), power control of an independent ("open loop" (and / or "closed loop" (e.g., "individual TPC accumulation"))) can be managed and operated for each "sidelink (and / or uplink) SPS process ( / configuration) (set)" through a predefined DCI format (e.g., "DCI 3 ( / 3A)") (which will be referred to as V2XSPS_TPCDCI).

[0308] Multiple (TPC) fields (with a preconfigured ( / signaled) size) may exist within the corresponding V2XSPS_TPCDCI, and the interconnection ( / linking) information between a specific (TPC) field index and a "(specific) sidelink (and / or uplink) SPS process ( / configuration)" (and / or "cell index where the (specific) sidelink (and / or uplink) SPS process ( / configuration) is configured ( / signaled)") and / or "V2X UE ID" can be configured through predefined (higher layer / physical layer) signaling.

[0309] The corresponding V2XSPS_TPCDCI can (exclusively) direct (or indicate) power control information corresponding to another cell (e.g., a secondary cell) (except for the primary cell (and / or the cell in which the V2XSPS_TPCDCI is received (e.g., the (primary cell) common search space))) in a “cross-carrier( / cell) scheduling format”.

[0310] For the corresponding V2XSPS_TPCDCI, (A) a new V2XTPC-RNTI value can be configured ( / signaled) and / or (B) an existing (WAN communication related) TPC-PUSCH-RNTI (and / or TPC-PUCCH-RNTI) value can be (shared and) reused. In the latter case, a field (e.g., “1 bit”) can be defined within the V2XSPS_TPCDCI to distinguish the corresponding DCI from the (existing) WAN communication related TPC DCI. The V2XSPS_TPCDCI related (payload) size can be defined to equally match the size of the (existing) WAN communication related TPC DCI (e.g., “DCI 3( / 3A)”) sent from the same (common( / UE-specific)) search space (SS) region (e.g., zero padding (and / or padding with a pre-configured( / signaled) value)) can be performed until the corresponding size becomes equal to the (payload) size of the (existing) WAN communication related TPC DCI).

[0311] Configuration ( / signaling) can be performed such that a “separate TPC accumulation” operation can be applied for each “sidelink (and / or uplink) SPS process( / configuration)”. Different (or independent) “open-loop parameters (e.g., “P_O” and / or “ALPHA”, etc.)” can be configured ( / signaled) for each “sidelink (and / or uplink) SPS process( / configuration)”, and / or different (or independent) power control parameters can be configured ( / signaled) for each (V2X message) PPP (and / or V2X message type( / characteristic (e.g., cycle period))) within a (single) specific “sidelink (and / or uplink) SPS process( / configuration)”, thereby allowing the V2X UE to apply interconnected power control parameters when transmitting a specific (V2X message) PPP (and / or V2X message type( / characteristic (e.g., cycle period))) within the corresponding “sidelink (and / or uplink) SPS process( / configuration)”.

[0312] In this document, for example, independent "(open-loop)" (and / or "(closed-loop)" (e.g., "separate TPC accumulation")) power control for each "sidelink (and / or uplink) SPS process (set)" can be achieved by specifying a "power offset value" within (a part (or all) of) the "(sidelink (and / or uplink) SPS process (set))" via predefined (higher layer ( / physical layer)) signaling.

[0313] As another example, in the case of configuring ( / signaling) multiple "sidelink (and / or uplink) SPS processes (configurations)", "(open-loop)" (and / or "(closed-loop)" (e.g., "separate TPC accumulation")) power control operations ( / parameters) can be commonly applied ( / managed and operated) among the multiple "sidelink (and / or uplink) SPS processes (configurations)".

[0314] Since the above examples of proposed methods can be included as one of the implementation methods of the present invention, it will be clear that the corresponding examples can be regarded as (or treated as) a proposed method. Additionally, although the above proposed methods can be implemented independently, the above proposed methods can also be implemented in the form of a combination (or integration) of parts of the proposed methods. For example, although the present invention is described based on the 3GPP LTE / LTE-A system for simplicity of description, the scope of systems to which the proposed methods can be applied can be extended to different systems other than the 3GPP LTE / LTE-A system. For example, the proposed methods according to the present invention can also be extendedly applied to D2D communication. In this document, for example, D2D communication refers to performing communication between a UE and another UE using a direct wireless channel. And, in this document, for example, although a UE refers to a user device, in the case where a network device such as a base station transmits / receives signals according to the communication method performed between UEs, the corresponding network device can also be regarded as a type of UE. Additionally, for example, the proposed methods according to the present invention can also be only limitedly applied to mode 2 V2X operation (and / or mode 1 V2X operation).

[0315] Additionally, for example, in the proposed methods according to the present invention, the "(sidelink and / or uplink - SPS) (activation / release) DCI" can be limitedly transmitted only through a "(PDCCH or EPDCCH) UE-specific search space" (or "PDCCH common search space").

[0316] Additionally, for example, in the proposed methods according to the present invention, the "(sidelink and / or uplink - SPS) (activation / release) DCI" can also be interpreted as a "mode 1 DCI" (received from a base station) (announcing PC5 (V2V) SPS-related scheduling information).

[0317] Figure 18 It is a block diagram of a UE in which embodiments of the present invention are implemented.

[0318] Referring to Figure 18 , UE 1100 includes a processor 1110, a memory 1120, and a radio frequency (RF) unit 1130. The processor 1110 implements the proposed functions, processes, and / or methods.

[0319] The RF unit 1130 is connected to the processor 1110 to transmit and receive radio signals.

[0320] The processor may include an application specific integrated circuit (ASIC), other chip sets, logic circuits, and / or data processing devices. The memory may include a read only memory (ROM), a random access memory (RAM), a flash memory, a memory card, a storage medium, and / or other storage devices. The RF unit may include a baseband circuit for processing radio signals. When an embodiment is implemented in software, the above technologies may be implemented by using modules (processing, functions, etc.) that execute the above functions. The modules may be stored in the memory and may be executed by the processor. The memory may be internal or external to the processor and may be connected to the processor by using various well-known means.

Claims

1. A method for receiving downlink control information (DCI) in a wireless communication system, the method being performed by a user equipment (UE), and the method comprises the following steps: Receiving, from a base station, semi-persistent scheduling (SPS) activation / release DCI; And Activating or releasing an SPS configuration based on the SPS activation / release DCI, wherein, if the SPS activation / release DCI is related to sidelink SPS between the UE and another UE, the SPS activation / release DCI includes (i) a sidelink SPS configuration index field and (ii) a sidelink SPS activation / release field, wherein the sidelink SPS configuration index field notifies a sidelink SPS configuration, wherein the sidelink SPS activation / release field notifies activation or release of the sidelink SPS configuration, and wherein, if the SPS activation / release DCI is related to uplink SPS between the UE and the base station for vehicle-to-everything (V2X) communication, the SPS activation / release DCI includes 3-bit information for information on cyclic shift of a demodulation reference signal (DM-RS), and the 3-bit information notifies an index of an uplink SPS configuration related to the uplink SPS.

2. The method according to claim 1, wherein, the sidelink SPS configuration index field includes information indicating one sidelink SPS configuration among a plurality of sidelink SPS configurations.

3. The method according to claim 1, wherein, the total bit size of the SPS activation / release DCI is greater than the total bit size of sidelink dynamic DCI.

4. The method according to claim 1, wherein, the sidelink SPS configuration index field is configured with 3 bits.

5. The method according to claim 1, wherein, the sidelink SPS activation / release field is configured with 1 bit.

6. A user equipment (UE), the UE comprises: A transceiver configured to transmit and receive radio signals; And A processor operatively connected to the transceiver, wherein the processor is configured to: Receive semi-persistent scheduling (SPS) activation / release downlink control information (DCI) from a base station, and Activate or release an SPS configuration based on the SPS activation / release DCI, wherein, if the SPS activation / release DCI is related to sidelink SPS between the UE and another UE, the SPS activation / release DCI includes (i) a sidelink SPS configuration index field and (ii) a sidelink SPS activation / release field, wherein the sidelink SPS configuration index field notifies a sidelink SPS configuration, wherein the sidelink SPS activation / release field notifies activation or release of the sidelink SPS configuration, and Wherein, if the SPS activation / release DCI is related to the uplink SPS between the UE and the base station for vehicle-to-everything V2X communication, the SPS activation / release DCI includes 3-bit information for information on the cyclic shift of the demodulation reference signal DM-RS, and the 3-bit information notifies the index of the uplink SPS configuration related to the uplink SPS.

7. The UE according to claim 6, Wherein, the sidelink SPS configuration index field includes information indicating one sidelink SPS configuration among a plurality of sidelink SPS configurations.

8. The UE according to claim 6, Wherein, the total bit size of the SPS activation / release DCI is greater than the total bit size of the sidelink dynamic DCI.

9. The UE according to claim 6, Wherein, the sidelink SPS configuration index field is configured with 3 bits.

10. The UE according to claim 6, Wherein, the sidelink SPS activation / release field is configured with 1 bit.

11. A method for transmitting downlink control information DCI in a wireless communication system, the method being performed by a base station, and the method comprising the steps of: generating a semi-static scheduling SPS activation / release DCI; and transmitting the SPS activation / release DCI to a user equipment UE, wherein, if the SPS activation / release DCI is related to the sidelink SPS between the UE and another UE, the SPS activation / release DCI includes (i) a sidelink SPS configuration index field and (ii) a sidelink SPS activation / release field, wherein, the sidelink SPS configuration index field notifies the sidelink SPS configuration, wherein, the sidelink SPS activation / release field notifies the activation or release of the sidelink SPS configuration, and wherein, if the SPS activation / release DCI is related to the uplink SPS between the UE and the base station for vehicle-to-everything V2X communication, the SPS activation / release DCI includes 3-bit information for information on the cyclic shift of the demodulation reference signal DM-RS, and the 3-bit information notifies the index of the uplink SPS configuration related to the uplink SPS.

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