NR V2X retransmission procedure

Abstract

A wireless communication system is described, the wireless communication system including a plurality of user equipments (UEs) communicating with each other using a sidelink (SL). For transmission of packets, such as data packets, using the sidelink, the transceiver is configured to determine one or more transmission requirements for transmission of the data packets using the sidelink. In response to the determined one or more transmission requirements, the transceiver is configured to transmit one or more control messages, the one or more control messages including one or more of the following: - A common control message containing parameters for HARQ-based transmissions using the sidelink and for blind or non-HARQ transmissions using the sidelink. - A control message containing parameters for blind or non-HARQ transmissions using the sidelink.

Description

[Technical field]

[0001] The present application relates to the field of wireless communication systems or networks, more particularly to enhancements or improvements relating to retransmission procedures, more particularly to the field of vehicle-to-everything (V2X) communications. Embodiments of the present invention relate to New Radio (NR) V2X procedures for blind and HARQ based (re)transmissions. [Background technology]

[0002] FIG. 1 includes a core network 102 and one or more radio access networks RANs, as shown in FIG. 1(a). 1 , R.A.N. 2 , ...RAN N FIG. 1(b) is a schematic diagram of an example of a terrestrial wireless network 100 including one or more base stations gNB 1 Or gNB 5 FIG. 1 is a schematic diagram of an example of a radio access network RANn that may include a respective cell 106 1 or 106 5Each of the base stations serves a specific area around the base station, which is represented diagrammatically by . The base stations are provided to serve users in the cell. One or more base stations may serve users in licensed and / or unlicensed bands. The term base station BS means gNB in ​​5G networks, eNB in ​​UMTS / LTE / LTE-A / LTE-A Pro, or just BS in other mobile communication standards. The users may be fixed or mobile devices. Also, the wireless communication system may be accessed by mobile or fixed IoT devices that connect to the base station or the user. The mobile or IoT devices may include physical devices, ground-based vehicles such as robots or automobiles, aircraft such as manned or unmanned aerial vehicles (UAVs), the latter also called drones, buildings, and other items or devices that have embedded therein electronics, software, sensors, actuators, etc., as well as network connections that enable these devices to collect and exchange data across the existing network infrastructure. Although FIG. 1(b) shows an exemplary diagram of five cells, the RANn may include more or fewer such cells, and the RANn may also include only one base station. FIG. 1(b) shows an exemplary diagram of the cells 106. 2 Located in the base station gNB 2 Two user UEs, also called user equipment UEs, served by 1 and UE 2 Another user UE 3 is a base station gNB 4 Cell 106 served by 4 As shown in the arrow 108 1 , 108 2 , 108 3 is the user UE 1 , U.E. 2 , U.E. 3 From base station gNB 2 , gNB 4 or base station gNB 2 , gNB 4 From User UE1 , U.E. 2 , U.E. 3 1(b) shows a schematic representation of an uplink / downlink connection for transmitting data to a cell 106, which may be realized in a licensed band or in an unlicensed band. 4 2 IoT devices in 110 1 , 110 2 110 are shown, which may be fixed devices or mobile devices. 1 is arrow 112 1 As shown in the schematic diagram, the base station gNB 4 The IoT device 110 accesses the wireless communication system via the 2 is arrow 112 2 As represented diagrammatically by 3 Each base station gNB 1 Or gNB 5 Each backhaul link 114 1 or 114 5 , for example via an S1 interface, to a core network 102, which is represented diagrammatically in FIG. 1(b) by an arrow pointing to “core”. The core network 102 may be connected to one or more external networks. Furthermore, each base station gNB 1 Or gNB 5 1 through the respective backhaul links 116, e.g., via the S1 or X2 interface or the XN interface in NR. 1 or 116 5 gNBs may be connected to each other via a sidelink channel, which is represented diagrammatically in Fig. 1(b) by an arrow pointing to "gNBs". Sidelink channels, also called device-to-device (D2D) communication, enable direct communication between UEs. In 3GPP, the sidelink interface is named PC5.

[0003] For data transmission, a physical resource grid may be used. The physical resource grid may comprise a set of resource elements onto which various physical channels and physical signals are mapped. For example, the physical channels may include a physical downlink shared channel, a physical uplink shared channel, and a physical sidelink shared channel (PDSCH, PUSCH, PSSCH) carrying user-specific data, also referred to as downlink payload data, uplink payload data, and sidelink payload data, a physical broadcast channel (PBCH) carrying, for example, a master information block (MIB) and one or more system information blocks (SIBs), a physical downlink control channel, a physical uplink control channel, and a physical sidelink control channel (PDCCH, PUCCH, PSCCH) carrying, for example, downlink control information (DCI), uplink control information (UCI), and sidelink control information (SCI). Note that the sidelink interface may support two stages of SCI. This refers to a first control region that includes some portion of the SCI and, optionally, a second control region that includes a second portion of the control information.

[0004] For the uplink, the physical channel may further include a physical random access channel (PRACH or RACH) that the UE uses to access the network once it has synchronized and acquired the MIB and SIB. The physical signal may comprise a reference signal or symbol (RS), a synchronization signal, etc. The resource grid may comprise a frame or radio frame having a specific duration in the time domain and a given bandwidth in the frequency domain. The frame may have a specific number of subframes of a predefined length, e.g., 1 ms. Each subframe may include one or more slots of 12 or 14 OFDM symbols depending on the cyclic prefix (CP) length. The frame may also consist of a smaller number of OFDM symbols, e.g., when utilizing a reduced transmission time interval (sTTI) or a minislot / non-slot based frame structure with several OFDM symbols.

[0005] The wireless communication system may be any single-tone or multi-carrier system using frequency division multiplexing, such as an Orthogonal Frequency Division Multiplexing (OFDM) system, an Orthogonal Frequency Division Multiple Access (OFDMA) system, or any other IFFT-based signal with or without CP, such as DFT-s-OFDM. Other waveforms such as non-orthogonal waveforms for multiple access, such as Filter Bank Multi-Carrier (FBMC), Generalized Frequency Division Multiplexing (GFDM) or Universal Filter Multi-Carrier (UFMC), may also be used. The wireless communication system may operate, for example, according to the LTE-Advanced pro standard, or the 5G or NR (New Radio) standard, or the NR-U (New Radio unlicensed) standard.

[0006] The wireless network or communication system shown in FIG. 1 may include different overlay networks, e.g., base stations gNB 1 Or gNB 5 The network may be heterogeneous, having a network of macro cells with each macro cell including a macro base station such as a 10G base station, and a network of small cell base stations (not shown in FIG. 1), such as femto or pico base stations.

[0007] In addition to the terrestrial wireless networks mentioned above, there are also non-terrestrial wireless communication networks (NTNs) including spaceborne transceivers, such as satellites, and / or airborne transceivers, such as unmanned aerial systems. The non-terrestrial wireless communication networks or systems may operate in a similar manner to the terrestrial system described above with reference to FIG. 1, for example according to the LTE-Advanced Pro standard or the 5G or new radio (NR) standard.

[0008] In a mobile communication network, such as a LTE or 5G / NR network as described above with reference to FIG. 1, there may be UEs that communicate directly with each other over one or more sidelink (SL) channels, for example using a PC5 interface. The UEs that communicate directly with each other over the sidelink may include vehicles that communicate directly with other vehicles (V2V communication), vehicles that communicate with other entities of the wireless communication network (V2X communication), e.g. roadside entities such as traffic signals, traffic signs, or pedestrians. The other UEs may not be vehicle-related UEs and may include any of the devices mentioned above. Such devices may also communicate directly with each other (D2D communication) using the SL channels.

[0009] When considering two UEs that communicate directly with each other via sidelink, both UEs may be served by the same base station, such that the base station can provide sidelink resource allocation configuration or assistance to the UEs. For example, both UEs may be within the coverage area of ​​a base station, such as one of the base stations shown in FIG. 1. This is called the "in-coverage" scenario. Another scenario is called the "out-of-coverage" scenario. "Out-of-coverage" does not mean that the two UEs are not within range of one of the cells shown in FIG. 1, but rather that these UEs are within the coverage area of ​​a base station, such as one of the base stations shown in FIG. 1. - may not be connected to the base station, e.g. not in an RRC connected state, and the UE does not receive any sidelink resource allocation configuration or assistance from the base station; and / or - connected to a base station, but for one or more reasons the base station may not provide sidelink resource allocation configuration or assistance to the UE; and / or - May be connected to base stations that do not support NR V2X services, e.g., GSM, UMTS, LTE base stations and NR base stations that do not support V2X services; Please note that this means

[0010] When considering two UEs communicating directly with each other over the sidelink, for example using a PC5 interface, one of the UEs may be connected with the BS and may relay information from the BS to the other UE over the sidelink interface. The relaying may be performed in the same frequency band (in-band relaying) or a different frequency band may be used (out-of-band relaying). In the first case, the communication on Uu and the communication on the sidelink may be separated using different time slots as in a Time Division Duplex (TDD) system.

[0011] Figure 2 is a schematic diagram of an in-coverage scenario where two UEs communicating directly with each other are both connected to a base station gNB. The base station gNB has a coverage area, which is represented diagrammatically by a circle 200, and basically corresponds to the cell diagrammatically represented in Figure 1. The UEs communicating directly with each other include both a first vehicle 202 and a second vehicle 204 within the coverage area 200 of the base station gNB. Both vehicles 202, 204 are connected to the base station gNB and further directly connected to each other via a PC5 interface. Scheduling of V2V traffic and / or interference management is assisted by the gNB via control signaling over the Uu interface, which is the radio interface between the base station and the UE. In other words, the gNB provides the UE with a SL resource allocation configuration or assistance, and the gNB allocates resources to be used for V2V communication over the sidelink. This configuration is also called Mode 1 configuration in NR V2X and Mode 3 configuration in LTE V2X.

[0012] FIG. 3 is a schematic diagram of an out-of-coverage scenario in which UEs that communicate directly with each other may be physically present within a cell of a wireless communication network, but are not connected to a base station, or some or all of the UEs that communicate directly with each other are connected to a base station, but the base station does not provide SL resource allocation configuration or assistance. Three vehicles 206, 208, 210 are shown to communicate directly with each other over a sidelink, for example using a PC5 interface. Scheduling of V2V traffic and / or interference management is based on algorithms implemented between the vehicles. This configuration is also referred to as Mode 2 configuration in NR V2X and Mode 4 configuration in LTE V2X. As mentioned above, the scenario of FIG. 3 being an out-of-coverage scenario does not necessarily mean that the respective Mode 2 UE (in the case of NR) or Mode 4 UE (in the case of LTE) is outside the coverage 200 of the base station, but rather means that the respective Mode 2 UE (in the case of NR) or Mode 4 UE (in the case of LTE) is not served by the base station, is not connected to a base station in the coverage area, or is connected to the base station but does not receive SL resource allocation configuration or assistance from the base station. Therefore, there may be a situation where UEs 206, 208, and 210 of NR mode 2 or LTE mode 4 are present in addition to UEs 202 and 204 of NR mode 1 or LTE mode 3 within the coverage area 200 shown in FIG. 2 .

[0013] In the above-mentioned scenario of vehicular user equipment UE, such multiple user equipments form a user equipment group, also simply referred to as a group, and communication within or between group members may be performed via a sidelink interface between the user equipments, such as a PC5 interface. For example, the above-mentioned scenario using vehicular user equipment may be employed in the field of transportation industry, where multiple vehicles equipped with vehicular user equipments are grouped, for example, by a remote driving application. Other use cases where multiple user equipments may be grouped for sidelink communication with each other include, for example, factory automation and power distribution. In the case of factory automation, multiple mobile or fixed machines in a factory may be equipped with user equipment and grouped together for sidelink communication to control the operation of the machines, for example, to control the operation of a robot. In the case of power distribution, entities in a power distribution network may be grouped together in a certain area of ​​the system and equipped with respective user equipment to communicate with each other via sidelink communication to monitor the system and address faults or outages in the power distribution network.

[0014] Of course, in the above use cases, sidelink communication is not limited to intra-group communication, rather sidelink communication may take place between any UEs, such as any pair of UEs.

[0015] In a mobile communication system or network as described above with reference to FIG. 1, for example in an LTE or 5G / NR network, each entity may communicate using one or more frequency bands. A frequency band includes a start frequency, an end frequency, and all intermediate frequencies between the start frequency and the end frequency. In other words, the start frequency, the end frequency, and the intermediate frequencies may define a certain bandwidth, for example 20 MHz. A frequency band may also be referred to as a carrier, a bandwidth portion (BWP), a subband, etc.

[0016] When a single frequency band is used, the communications may be referred to as single-band operation, e.g. the UE transmits / receives radio signals to / from other network entities on frequencies within the 20 MHz band.

[0017] When using two or more frequency bands, the communication may be referred to as multi-band operation, or wideband operation, or carrier aggregation operation. The frequency bands may have different bandwidths or the same bandwidth, such as 20 MHz. For example, for frequency bands with the same bandwidth, the UE may transmit / receive radio signals to / from other network entities on frequencies within two or more frequencies in the 20 MHz band, such that the frequency range for wireless communication is a multiple of 20 MHz. The two or more frequency bands may be contiguous / adjacent frequency bands, or some or all of the frequency bands may be separated in the frequency domain. Multi-band operation may include frequency bands in the licensed spectrum, or frequency bands in the unlicensed spectrum, or frequency bands in both the licensed and unlicensed spectrum. Carrier aggregation CA is an example of using two or more frequency bands in the licensed and / or unlicensed spectrum.

[0018] 5G New Radio (NR) can support operation in unlicensed spectrum, and multi-band operation can include frequency bands in the unlicensed spectrum band. This may be referred to as NR-based access to unlicensed spectrum (NR-U), and the frequency bands may be referred to as sub-bands. The unlicensed spectrum may include bands that may coexist with IEEE 802.11, such as the 5 GHz band and the 6 GHz band. NR-U may support bandwidths that are integer multiples of 20 MHz, for example, due to regulatory requirements. The division of sub-bands is performed to minimize interference with coexisting systems, such as IEEE 802.11 systems, that may operate in one or more of the same bands with the same nominal bandwidth channel, such as a 20 MHz channel. Other examples of coexisting systems may use sub-bands with different sub-band sizes and nominal frequencies than the IEEE 802.11 systems mentioned above. For example, the unlicensed spectrum may include the 5 GHz band, the 6 GHz band, the 24 GHz band, or the 60 GHz band. Examples of such unlicensed bands include the Industrial, Scientific, and Medical (ISM) radio bands, which are internationally reserved for the use of radio frequency energy for industrial, scientific and medical purposes other than telecommunications.

[0019] During operation using unlicensed subbands, Listen-Before-Talk (LBT) is performed for each subband separately. This may occur, for example, due to interference from other communication systems coexisting on the same band, such as other Public Land Mobile Networks (PLMNs) or systems operating according to IEEE 802.11 specifications, where one or more subbands are busy or occupied. In such a situation, a transmitter, either the transmitting gNB or the transmitting UE, may only transmit in subbands that are detected to be not busy, also referred to as free or unoccupied subbands, as determined by the LBT algorithm. For example, with transmissions of more than 20 MHz in the 5 GHz operable unlicensed band, a transmitter, such as a gNB or a UE, performs Listen-Before-Talk (LBT) in each subband separately. Once the LBT results are available for each subband, a device, e.g., a gNB in ​​the downlink DL or a UE in the uplink UL, can transmit in those subbands that are determined to be free or unoccupied, i.e., won subbands, and cannot transmit in occupied, busy or non-won subbands.

[0020] Please note that the information in the above sections is merely intended to enhance understanding of the background of the invention, and therefore may contain information that does not form part of prior art already known to those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0021] Starting from the prior art as discussed above, there is a need for enhancements or improvements regarding retransmission procedures.

[0022] Embodiments of the invention will now be described in more detail with reference to the accompanying drawings. [Brief description of the drawings]

[0023] [Figure 1(a)] FIG. 1(a) shows a schematic diagram of an example of a wireless communication system. [Figure 1(b)] FIG. 1(b) shows a schematic diagram of an example of a wireless communication system. [Diagram 2] FIG. 2 is a schematic diagram of an in-coverage scenario in which UEs that communicate directly with each other are connected to a base station. [Diagram 3] FIG. 3 is a schematic diagram of an out-of-coverage scenario in which UEs directly connected to each other do not receive SL resource allocation configuration or assistance from the base station. [Figure 4] FIG. 4 is a schematic diagram for operating a network node in mode 1. [Diagram 5] FIG. 5 is an example of a DAI procedure for scheduling HARQ and blind transmissions. [Figure 6] FIG. 6 shows an example of the use of DCI containing a single PUCCH position for a total of (MxP) transmissions. [Figure 7] FIG. 7 illustrates an example of the use of a DCI that includes multiple PUCCH resources corresponding to each of the retransmission resource positions. [Figure 8] FIG. 8 is an example using DCI that includes the PUCCH resource location corresponding to the first transmission; for subsequent transmissions, the TX UE can assume a time gap between the resource locations of these transmissions and derive the respective PUCCH locations accordingly. [Figure 9] FIG. 9 is a schematic diagram of multiplexing HARQ-based and blind / HARQ-less transmissions in a single PUCCH according to an embodiment. [Figure 10] FIG. 10 is a schematic block diagram for explaining a timeline separation process according to an embodiment. [Figure 11] FIG. 11 is a schematic diagram of a network operation according to an embodiment in which a base station is configured to transmit a single DCI indicating a HARQ-based transmission to a TX UE and receive a single HARQ feedback. [Figure 12]FIG. 12 is a schematic diagram of a network operation according to an embodiment in which a base station is configured to transmit a single DCI indicating a HARQ-based transmission to a TX UE and receive a single HARQ feedback, and the TX UE receives multiple feedbacks from the RX UEs. [Figure 13] FIG. 13 is a schematic diagram of a network operation according to an embodiment in which a base station is configured to transmit a single DCI indicating a HARQ-based transmission to a TX UE and receive a single HARQ feedback, and the TX UE transmits multiple SCIs to a RX UE. [Figure 14] FIG. 14 is a schematic diagram of a network operation according to an embodiment in which a base station is configured to transmit a single DCI indicating a HARQ-based transmission to a TX UE and receive a single HARQ feedback, and the TX UE transmits multiple SCIs to a RX UE and receives multiple feedbacks from the RX UE. [Figure 15] FIG. 15 is a schematic diagram of a network operation according to an embodiment in which a base station is configured to transmit a single DCI indicating a HARQ-based transmission to a TX UE and receive a single HARQ feedback, and the TX UE transmits multiple SCIs to a RX UE and receives multiple feedbacks related to data content from the RX UE. [Figure 16] FIG. 16 is a schematic diagram of a network operation according to an embodiment in which a base station is configured to transmit multiple DCIs to a TX UE and receive multiple HARQ feedbacks, and the TX UE transmits multiple SCIs to a RX UE and receives feedback from the RX UE in response to each SCI. [Figure 17] FIG. 17 is a schematic diagram of a network operation according to an embodiment in which a base station is configured to transmit multiple DCIs to a TX UE and receive multiple HARQ feedbacks, and the TX UE transmits multiple SCIs to a RX UE and receives feedback from the RX UE in response to each data transmission. [Figure 18]FIG. 18 is a schematic diagram of a cell, such as a cell in the network of FIG. 1, having a coverage area divided into multiple zones. [Figure 19] FIG. 19 illustrates an example of a computer system capable of executing units or modules as well as method steps described according to the approach of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings, in which like or similar elements are given the same reference numerals, and in which:

[0025] In a wireless communication system or network, the initial Vehicle-to-Everything (V2X) specification, as described above with reference to FIG. 1, is included in Release 14 of the 3GPP® standard. Resource scheduling and allocation have been modified according to the requirements of V2X, but the original Device-to-Device (D2D) communication standard is used as the basis for the design.

[0026] Release 15 of the LTE V2X standard (also known as improved V2X or eV2X) was completed in June 2018 and is now targeting Release 16, which 3GPP is looking forward to with its first release 5G NR V2X. NR V2X identifies a set of use cases to be realized, and one of the key focuses of these use cases is to guarantee a certain Quality of Service (QoS) for a given application service.

[0027] Based on the recently completed Rel.16 work item, 3GPP agreed to operate in two configurations in terms of resource allocation: Mode 1 and Mode 2. V2X UEs operating in Mode 1 get scheduling information for sidelink (SL) transmissions from the base station (BS / eNB / gNB), while Mode 2 UEs perform resource selection autonomously. It was also agreed that unicast and groupcast transmissions support hybrid automatic repeat request (HARQ) feedback, while broadcast transmissions do not support this feature. All comm / cast type transmissions also support blind retransmissions, which can be used in cases where the packet delay budget (PDB) does not allow the use of HARQ feedback due to delay constraints.

[0028] Once resources are allocated, the TX (transmitting) UE has to report to the RX (receiving) UE about the resources allocated for transmission using Sidelink Control Information (SCI). A single SCI contains information related to only [2, 3 or 4] (re)transmissions, but it is agreed that an overall of 32 (re)transmissions per packet are allowed.

[0029] The NR V2X system has two operating modes: Mode 1 and Mode 2. V2X Mode 1 configuration allows Sidelink (SL) (Vehicle-to-Vehicle / V2V) communication by base stations (BS / eNB / gNB) for resource scheduling and interference management for vehicular UEs within the base station's coverage. Control signaling is provided to the UEs over the Uu interface (via Downlink Control Indicator (DCI)). V2X Mode 2 configuration for SL communication is performed autonomously using a distributed (decentralized) algorithm between UEs based on pre-configured resource configuration.

[0030] In mode 1, the base station is responsible for selecting and allocating resources used by the TX UEs for transmitting (and retransmitting) packets to the RX UEs. The TX UE requests resources from the base station by using SR / BSR (Scheduling Request / Buffer Status Report). During the resource request, the base station allocates resources based on higher layer information about the priority, reliability and latency requirements attached to the packet. Based on this information, the base station decides, depending on the base station implementation (scheduler), the following: ● Whether the packet requires HARQ feedback or blind retransmission (based on the reliability requirements). ● The number of resubmissions in any of the above schemes (based on PDB requirements). ● Resources used for (re)transmission by the TX UE (based on resource availability). ● Resources used by the TX UE on the PUCCH (Physical Uplink Control Channel) to provide feedback (only in case of HARQ feedback) to the base station. ● The base station then informs the TX UE about the resources to be used for the (re)transmission by sending Downlink Control Information (DCI) to the TX UE. In LTE, the DCI only contained the frequency location of the initial transmission and the retransmission and the time gap between them, since the maximum number of transmissions of a packet was limited to 2. Since the maximum number loaded in NR is 32, the embodiments described herein provide an efficient solution for the DCI structure.

[0031] In Fig. 4, a schematic diagram for operating in mode 1 is shown. A base station, such as the gNB of Fig. 1, receives a message 312 from a TX UE, e.g., one of the UEs or IoT devices of Fig. 1. 1 That is, the TX UE requests resources by receiving SR / BSR to the base station. The base station can use higher layer information 314 to determine important parameters for the transmission. 2The base station may then transmit DCI to the TX UE. 3 The TX UE may then transmit SCI and / or data to the RX UE. 4 The RX UE can then transmit a HARQ ACK / NACK to the TX UE. The TX UE can then transmit one or more respective messages 312 5 The HARQ feedback can be forwarded to the base station by

[0032] In the case of blind retransmission, the base station does not provide information regarding the resources used for HARQ feedback, but only provides resources for the actual transmission of the packet, which is then forwarded by blind retransmission.

[0033] The TX UE in turn uses this resource information to send Sidelink Control Information (SCI) to the RX UE, providing information on which resources it can receive the transmission on. The RX UE maintains a timer after receiving every (re)transmission. Upon receiving a transmission, the timer is started. If another transmission of the same packet arrives at the RX UE before the timer expires (having the same HARQ process ID and New Data Indication (NDI) and not a new transmission being started), the RX UE keeps the previous transmission in a buffer, uses both transmissions to decode the packet and restarts the timer. The same process is repeated until the RX UE successfully decodes the packet or the timer expires and the buffer is cleared.

[0034] Since the total number of retransmissions (up to 32) exceeds the number of retransmission resources that can be specified in the SCI (up to 4), multiple SCIs (and possibly DCIs) will be needed to inform the TX UE (and subsequent RX UE) about the resources used for retransmissions. The embodiments provide procedures for using single or multiple DCIs to transmit SCIs that handle multiple (re)transmissions. In the context of the embodiments described herein, this is referred to as Idea 1.3, while the generally proposed new DCI structure is described in the embodiments referred to as Ideas 1.1 to 1.4.

[0035] Furthermore, in case of HARQ based retransmissions, the base station has the additional responsibility of allocating PUCCH resources to the TX UEs so that the TX UEs can report the status (ACK / NACK) of a given transmission to the base station. The different procedures followed for specifying retransmission and feedback resources in DCI are described in the embodiment referred to as idea 1.3.

[0036] In the SCI sent by the TX UE to the RX UE, the instances and the procedure to be followed when HARQ feedback is sent back to the TX UE are described in relation to the embodiment called idea 4.1. As described in European application EP19192133, there is no need to specify feedback resources in the PSFCH (Physical Sidelink Feedback Channel) since there is an implicit mapping between the data transmitted in the PSFCH and the position of the feedback in the PSFCH.

[0037] In Mode 2, the TX UE is responsible for selecting and allocating resources for transmission to the RX UEs. The TX UE is also responsible for deciding if a packet requires HARQ feedback or blind retransmission, along with other decisions described in connection with Mode 1 that are handled by the base station. The procedures that the TX UE follows to make these decisions are described in connection with the embodiment referred to as Idea 5.

[0038] For blind retransmission, the TX UE only needs to report via the SCI to the RX UE about the resources used for the (re)transmission of the packet. In NR, with the agreement that the SCI can only contain [2, 3 or 4] retransmission resource positions, multiple SCIs are required if the total number of retransmissions (up to 32) exceeds the number of retransmission resources that can be specified in the SCI. Essentially, the same procedure is followed as described in relation to blind retransmission in Mode 1.

[0039] For HARQ retransmissions, the TX UE can follow the same procedure as described for mode 1 above. The RX UE needs to know how long it has to hold the different retransmitted versions of a packet until it can clear its buffers. This can be done with a preconfigured or PC5-RRC configured retransmission timer, which is started / reset after a transmission or retransmission and flushes the buffer when it reaches a preconfigured threshold.

[0040] The present invention provides improvements and enhancements in wireless communication systems or networks that address the above-mentioned problems by providing an efficient SCI structure. More specifically, embodiments of the present invention avoid signaling overhead for providing location or location information while providing actual location / location with a desired accuracy. Embodiments of the present invention can be implemented in a wireless communication system such as that shown in FIG. 1, including a base station and a user such as a mobile terminal or IoT device. FIG. 18 is a schematic diagram of a wireless communication system including a transmitter 300, such as a base station, and one or more receivers 302, 304, such as user equipment UE. The transmitter 300 and receivers 302, 304 may communicate over one or more wireless communication links or channels 306a, 306b, 308, such as radio links. The transmitter 300 includes one or more antennas ANT (antennas) coupled to each other. T Alternatively, the receivers 302, 304 may include an antenna array having multiple antenna elements, a signal processor 300a, and a transceiver 300b. UEor an antenna array having multiple antennas, signal processors 302a, 304a, and transceivers 302b, 304b. The base station 300 and the UEs 302, 304 may communicate via respective first wireless communication links 306a and 306b, such as a wireless link using a Uu interface, while the UEs 302, 304 may communicate with each other via a second wireless communication link 308, such as a wireless link using a PC5 / sidelink (SL) interface. The UEs may communicate with each other via the sidelink (SL) when they are not served by the base station, are not connected to the base station, e.g., are not in an RRC connected state, or more generally, when no SL resource allocation configuration or assistance is provided by the base station. The system or network of FIG. 18, one or more UEs 302, 304, and the base station 300 may operate in accordance with the teachings of the invention described herein.

[0041] The present invention relates to a transceiver for a wireless communication system, the wireless communication system including a plurality of user equipments (UEs) communicating with each other using a side link (SL), wherein: For transmission of a packet, such as a data packet, over the sidelink, the transceiver determines one or more transmission requirements for transmission of the data packet over the sidelink; In response to the determined one or more transmission requirements, the transceiver transmits one or more control messages, the one or more control messages comprising: - a common control message including parameters for HARQ-based transmissions using sidelinks and blind or non-HARQ (HARQ-free) transmissions using sidelinks, or - a control message including parameters for a HARQ-based transmission using sidelink, or - a control message, including parameters for blind or non-HARQ transmissions using sidelink; including one or more of A transceiver is provided (see, for example, claim 1).

[0042] According to an embodiment (see, for example, claim 2), in a transceiver, one or more transmission requirements are: - whether a packet requires HARQ feedback or blind retransmission based on reliability requirements, e.g., QoS or channel conditions; - the number of retransmissions for the HARQ feedback scheme and / or the blind retransmission scheme, e.g. based on packet delay budget (PDB) requirements; - resources to use for transmission and retransmission using sidelink based on resource availability, e.g., resource congestion status, Contains one or more of the following:

[0043] According to an embodiment (see e.g. claim 3), the transceiver determines one or more transmission requirements in response to higher layer information about the packet, such as priority, PDB or an acceptable packet error rate (PER) (related to the reliability associated with the packet).

[0044] According to an embodiment (see e.g. claim 4), the transceiver is a base station of a wireless communication system communicating with a transmitting UE (TX UE) using a Uu link, the TX UE communicating with one or more receiving UEs (RX UEs) using a sidelink, the transmitting UE and / or the receiving UE being in NR mode 1.

[0045] According to an embodiment (see, for example, claim 5), in the transceiver, the base station comprises: - Dynamic grant, in which the base station sends DCI to the TX UE; - configured grant type 1, where the base station configures resources for the TX UE via RRC signaling; - configured grant type 2, where the base station configures resources for the TX UE via RRC signaling and DCI is sent to activate / deactivate the grant; , and transmit one or more control messages to the TX UE using one or more of the following:

[0046] According to an embodiment (see, for example, claim 6), in the transceiver, each of the one or more control messages comprises a common control message parameter, the common control message parameter being: - Resource location display, - Slot aggregation display, - the total number of retransmissions, - MCS level, - Max TX power, - Destination ID, - Cast type, - transmission procedure indication, e.g. blind transmission or retransmission or HARQ enabled transmission, - Priority display, Contains one or more of the following:

[0047] According to an embodiment (see e.g. claim 7), in the transceiver, the resource location indication comprises a time and frequency location of a transmission and / or one or more retransmissions for a given maximum or allowable number of transmissions and / or retransmissions, e.g. 32 retransmissions in NR SL, Wherein, if the frequency location or subchannel of the initial transmission and one or more retransmissions is the same, the resource location indication is: - a bitmap indicating the time slots in which retransmissions occur, e.g. in the form of a vector or in the form of an index mapped to a table in the TX UE containing multiple bitmap vectors; - a timing offset that allows the receiving UE to derive the time slot in which the retransmission occurs until the total number of possible retransmissions is reached; Includes at least one of the following: Here, if the frequency locations or subchannels of the initial transmission and one or more retransmissions are different, the resource location indication comprises a time-frequency pattern indicating the time and frequency location of the resource, e.g. in the form of an index that is mapped to a table in the TX UE that contains multiple time-frequency patterns.

[0048] According to an embodiment (see e.g. claim 9), in the transceiver, the TX UE is configured with a parameter, e.g. a PSSCH-aggregation factor parameter using RRC signaling, which indicates the number of slots to be aggregated for the transmission of a packet, e.g. for a jumbo packet using multiple PSSCH regions between slots, and The slot aggregation indication only indicates the frequency or subchannel and starting point of the first slot to be used.

[0049] According to an embodiment (see, for example, claim 9), in the transceiver, the time offset between each aggregated slot is pre-configured or configured using semi-static signaling such as RRC.

[0050] According to an embodiment (see, for example, claim 10), in the transceiver, the control message is - a retransmission type indication, indicating whether one or more retransmissions on the sidelink are HARQ-based retransmissions or blind retransmissions; - Downlink Allocation Index (DAI), - a retransmission feedback resource location indication indicating a resource location for transmitting feedback from the TX UE to the base station, e.g. on a PUCCH; A common control message includes one or more of the following:

[0051] According to an embodiment (see, for example, claim 11), in the transceiver, the retransmission type indication is - is explicit and includes an explicit parameter indicating whether the transmitted packet uses HARQ-based retransmission or blind retransmission, or - Implicitly, by setting one or more predetermined parameters in the DCI to a pre-defined or default value.

[0052] According to an embodiment (see, for example, claim 12), in the case of an implicit retransmission type indication, in the transceiver: The use of blind retransmissions is - using non-numeric or default or pre-configured values ​​of parameters such as PUCCH resource indicator indicating the resource used for feedback from the TX UE to the base station, for example, on PUCCH, or a time gap such as PSSCH / PDCCH-HARQ timing indicator between the DCI and feedback, for example, on PUCCH, or - resource location indication for transmission and / or retransmission towards a set or resource pool of resources that does not include any resource of the PSFCH; and / or The use of HARQ-based retransmissions is - resource location indication for transmission and / or retransmission towards a set or resource pool of resources including resources of the PSFCH; As shown by: and / or indicated by the use of a destination ID, priority information or cast type, e.g. transmission resources for broadcast or a destination ID with no HARQ configured.

[0053] According to an embodiment (see, for example, claim 13), in a transceiver, The DCI includes a downlink allocation index (DAI), the DAI includes a counter DAI (cDAI) and a total DAI (tDAI), and If the DCI is for blind retransmission using sidelink, - the counter DAI is not incremented or is assigned a default value or a predefined value, such as -1, and / or - DCI does not count towards your total DAI, and / or - the TX UE ignores the counter DAI, and / or - The counter DAI is incremented, but the counter DAI of subsequent DCIs for HARQ-based retransmissions is not incremented.

[0054] According to an embodiment (see, for example, claim 14), in a transceiver, The DCI includes a downlink allocation index (DAI), the DAI includes a counter DAI (cDAI) and a total DAI (tDAI), and A counter DAI is incremented if the DCI is for a HARQ-based retransmission and if the DCI is for a blind retransmission, where the transceiver increments the counter DAI for DCI indicating a blind or HARQ-less transmission and / or retransmission reported from a TX UE for a HARQ-less or blind transmission.

[0055] According to an embodiment (see, for example, claim 15), the transceiver comprises: If the DCI for no HARQ or blind transmission is correctly received at the TX UE, the transceiver receives an ACK from the TX UE on the designated PUCCH resource to signal that no further resources are required for the given transmission and increments a counter DAI; If the DCI for no HARQ or blind transmission is received erroneously at the TX UE, the transceiver receives a NACK from the TX UE on the designated PUCCH resource.

[0056] According to an embodiment (see, for example, claim 16), in a transceiver, In case of blind retransmission and HARQ-based retransmission, the transmission position indication and / or retransmission position indication in the DCI indicates some or all of the transmission and / or retransmission positions; In the case of only HARQ-based retransmission, the retransmission location indication in the DCI sent to the TX UE indicates the PUCCH resources on which the TX UE can forward the HARQ feedback received from the RX UE to the base station.

[0057] According to an embodiment (see e.g. claim 17), in the transceiver, in the case of HARQ based retransmissions, the retransmission position indication in the DCI indicates the number of transmission and / or retransmission resource positions, where the number of transmission and / or retransmission resource positions is MxP, where MxP is the maximum or allowable number of transmissions and / or retransmissions for a packet, e.g. not to exceed 32 retransmissions for NR, where M is the number of transmission and / or retransmission resource positions contained in a single DCI, and where P is the number of DCIs transmitted for a given packet.

[0058] According to an embodiment (see e.g. claim 18), in the transceiver, the DCI comprises a single PUCCH location for M transmission and / or retransmission resource locations, the transceiver comprising: - transmitting DCI comprising M transmission and / or retransmission resource locations and only one PUCCH location; - receiving, in response to the DCI, a composite feedback for the RX UE from the TX UE for all M transmissions by using a single PUCCH location; - Repeat transmission of the DCI P times until feedback indicates successful decoding of the packet at the RX UE or until the maximum number of retransmissions MxP is reached.

[0059] According to an embodiment (see e.g. claim 19), in a transceiver, the DCI comprises a number of PUCCH positions for each transmission and / or retransmission resource position, the transceiver comprising: - transmitting DCI comprising M transmission and / or retransmission resource locations and one PUCCH location for each transmission and / or retransmission resource location; - receiving, in response to the DCI, feedback for the RX UEs for each of the M transmissions by using a PUCCH position for transmission and / or retransmission from the TX UE; - Repeat transmission of the DCI P times until feedback indicates successful decoding of the packet at the RX UE or until the maximum number of retransmissions MxP is reached.

[0060] According to an embodiment (see, for example, claim 20), in a transceiver, the DCI comprises a plurality of PUCCH locations for a plurality of transmission and / or retransmission resource locations, the transceiver comprising: - transmitting DCI comprising MxP transmission and / or retransmission resource locations and a PUCCH location after every M transmission and / or retransmission resource location; - receiving feedback for RX UEs from TX UEs for every M-th transmission by using a PUCCH position for transmission and / or retransmission in response to the DCI; - Continue receiving feedback from the TX UE every M-th transmission until the feedback indicates successful decoding of the packet at the RX UE or until the maximum number of retransmissions MxP is reached.

[0061] According to an embodiment (see, for example, claim 21), in the transceiver, the DCI is indicated explicitly or implicitly, In case of explicit indication, the DCI contains all PUCCH positions for transmission and / or retransmission, In the case of an implicit indication, the DCI includes the PUCCH resource location corresponding to the first transmission, and for the second or subsequent transmissions and / or retransmissions, the TX UE may specify the PUCCH location for the second or subsequent transmissions and / or retransmissions as: - using the time gap between resource positions for the second and / or subsequent transmissions and / or retransmissions and applying the given time gap starting from the PUCCH resource position for the first transmission, or - deriving using a time gap between the first transmission position and the PUCCH resource position and applying the given time gap to the second and subsequent retransmission resource positions; At least one of the following is performed.

[0062] According to an embodiment (see, for example, claim 22), in the transceiver, the DCI is indicated explicitly or implicitly, Transceivers were first used in DCI. - a HARQ-Timing Indicator pointing to the slot in which the first HARQ feedback is reported, and - a PUCCH Resource Indication (PRI) indicating one of multiple configured PUCCH configurations to use for PUCCH transmission in the slot; indicates, By applying the same offset to the PUCCH resources as is applied to the PSSCH transmission, one or more slots for the second and subsequent HARQ-feedback are determined.

[0063] According to an embodiment (see, for example, claim 23), the transceiver comprises: - receiving an ACK from the TX UE when the TX UE determines that all permissible transmissions and / or retransmissions for the packet have been completed; or - Receive an explicit parameter indicating that all permissible transmissions and / or retransmissions for a packet have been completed.

[0064] According to an embodiment (see, e.g., claim 24), the transceiver stops allocating further resources for the packet in response to an ACK or an explicit indication that transmission and / or retransmission for the packet is completed, independent of feedback on the PSFCH.

[0065] According to an embodiment (see, for example, claim 25), in the transceiver, the control message is a control message for HARQ-based retransmission, the control message for HARQ-based retransmission comprising: - resources used by the PUCCH, - the time gap between DCI and PUCCH; - the slot offset between DCI reception and the first sidelink transmission scheduled by DCI, The parameter indicates one or more of:

[0066] According to an embodiment (see, for example, claim 26): The transceiver is a transmitting UE (TX UE) that communicates with one or more receiving UEs (RX UEs) using a sidelink, the transmitting UE and / or the receiving UE are in NR mode 2, and The one or more control messages are sidelink control information (SCI) messages that contain sidelink control information (SCI).

[0067] According to an embodiment (see, for example, claim 27), in the transceiver, the one or more transmission requirements are: - resources used by the PUCCH for the TX UE to provide feedback to the base station in case of HARQ-based transmission using sidelink; - a time gap between a PDCCH transmission including DCI to the TX UE and a PUCCH transmission including feedback from the TX UE to the base station; - the slot offset between DCI reception and the first sidelink transmission scheduled by DCI; The present invention further includes one or more of the following:

[0068] The present invention relates to a user equipment for a wireless communication system, the wireless communication system comprising a plurality of user equipments (UE) for communicating with each other using a side link (SL), wherein: The user equipment is a transmitting user equipment (TX UE) served by a base station of a wireless communication system, communicating with one or more receiving user equipments (RX UE) using a sidelink, and For transmission over the sidelink of a packet, such as a data packet, the TX UE receives one or more control messages, such as a DCI, from a serving base station in response to one or more transmission requirements for the transmission of the data packet, the one or more control messages including: - a common DCI including parameters for HARQ-based transmissions using sidelink and blind or non-HARQ transmissions using sidelink, or - DCI for HARQ-based retransmissions containing parameters for HARQ-based transmissions using sidelink, or - DCI for non-HARQ retransmissions, including parameters for blind transmissions or non-HARQ transmissions using sidelink; including one or more of A user equipment is provided (see, for example, claim 28).

[0069] According to an embodiment (see eg claim 29) in the user equipment, the serving base station comprises or is the inventive transceiver as described above.

[0070] According to an embodiment (see, for example, claim 30), in the user equipment, the control message is a common DCI, In response to the common DCI, the TX UE: - a single SCI for all resource locations with an indication that feedback must be sent for each transmission, or - multiple SCIs including different subsets of resource locations described in the DCI and specifying for each transmission feedback must be transmitted; is expected to send at least one of Upon receiving feedback from the RX UE for each transmission, the TX UE provides feedback to the base station regarding the PUCCH resources for the transmission, either implicitly derived or explicitly indicated in the DCI.

[0071] According to an embodiment (see, for example, claim 31), in the user equipment, the control message is a common DCI, In response to the common DCI, the TX UEs are expected to transmit a single SCI as an SCI with at least two stages.

[0072] According to an embodiment (see, for example, claim 32), in the user equipment, the control message is a common DCI, The DCI includes a downlink allocation index (DAI), and the DAI includes a counter DAI (cDAI) that is incremented to be successfully received at the TX UE when the DCI is for a HARQ-based retransmission and when the DCI is for a blind retransmission; If the DCI for no HARQ transmission or blind transmission is successfully received, the TX UE sends an ACK to the base station and increments a counter DAI for the DCI indicating a blind retransmission to the base station.

[0073] According to an embodiment (see e.g. claim 33), in the user equipment, if unexpected traffic arrives before the HARQ-ACK for the no HARQ transmission is reported to the base station and the TX UE needs more resources, the TX UE reuses the HARQ-ACK feedback for the blind transmission as a Scheduling Request (SR) to inform the base station that more resources are needed, e.g. by sending a NACK for the blind transmission in case more resources are needed.

[0074] According to an embodiment (see e.g. claim 34), in a user equipment, The TX UE receives from the base station one or more common DCIs indicating slot aggregation and one or more DCIs for packets requiring only one-time transmission or one-shot transmission; When slot aggregation on the sidelink is active, the TX UE applies the same HARQ timeline for all transmissions for which the TX UE has to send a HARQ-ACK to the base station, where PSSCH aggregation may always be active or may be activated by the base station using RRC or DCI signaling, and the HARQ timeline is for the maximum slot aggregation that is configured or activated for all transmissions; The HARQ timeline is the time it takes from the time the TX UE receives the DCI to the time the TX UE is ready to send feedback to the base station after it receives and decodes the transmission.

[0075] The present invention relates to one or more base stations; A plurality of user equipments (UEs) communicating with each other using a side link (SL), the plurality of UEs including a transmitting UE (TX UE), the TX UE communicating with one or more receiving UEs (RX UEs) using the side link; A wireless communication system comprising: The base station serves the TX UE; For transmission over the sidelink of a packet, such as a data packet, the base station determines one or more transmission requirements for the transmission over the sidelink of the data packet, and in response to the determined one or more transmission requirements, the base station transmits one or more control messages to the TX UE, the one or more control messages comprising: - a common control message including parameters for HARQ-based transmissions using the sidelink and blind or non-HARQ transmissions using the sidelink, or - a control message for HARQ-based retransmission comprising parameters for a HARQ-based transmission using sidelink, or - a control message for non-HARQ retransmissions, including parameters for blind transmissions or non-HARQ transmissions using sidelink; one or more of the TX UE receives one or more control messages from the base station, transmits the one or more control messages to the RX UE, and transmits packets to the RX UE according to parameters indicated in the one or more control messages; A wireless communication system is provided (see, for example, claim 35).

[0076] The present invention relates to one or more inventive base stations as described above; A plurality of user equipments (UEs) of the present invention communicating with each other using a side link (SL), the plurality of UEs including a transmitting UE (TX UE) as described above, the TX UE receiving a service provided by a base station and communicating with one or more receiving UEs (RX UEs) using the side link; Equipped with the TX UE receives one or more control messages from the base station, sends one or more control messages to the RX UE, and further sends packets to the RX UE according to parameters indicated in the one or more control messages; A wireless communication system is provided (see, for example, claim 36).

[0077] According to an embodiment (see, for example, claim 37), in a wireless communication system, The base station sends a single DCI to the TX UE, indicating a HARQ-based transmission, transmission and / or retransmission resource location and a single PUCCH location; The TX UE sends a single SCI to the RX UE, The RX UE sends a single HARQ feedback to the TX UE, where the RX UE combines all received retransmissions and sends the HARQ feedback only after successfully decoding a packet or after a maximum number of retransmissions; and The TX UE relays a single HARQ feedback to the base station using a single PUCCH resource defined in a single DCI.

[0078] According to an embodiment (see, for example, claim 38), in a wireless communication system, The base station sends a single DCI to the TX UE indicating a HARQ-based transmission and including a single PUCCH location for a transmission and / or retransmission resource location; The TX UE sends a single SCI to the RX UE, The TX UE receives multiple HARQ feedbacks from the RX UE, but only notifies the base station if the RX UE successfully decodes the packet; The TX UE schedules a CBG-based transmission to the RX UE using a single SCI, e.g. including several code blocks grouped into a CBG, and expects multiple feedbacks, e.g. one per CBG.

[0079] According to an embodiment (eg see claim 39), in a wireless communication system, a TX UE stops retransmission when a RX UE responds with a positive ACK. According to an embodiment (see, for example, claim 40), in a wireless communication system, The base station sends a single DCI to the TX UE indicating a HARQ-based transmission and including a single PUCCH location for a transmission and / or retransmission resource location; The TX UE sends a plurality of SCIs to the RX UE, each SCI having a retransmission resource location; The RX UE combines all received retransmissions and sends HARQ feedback only after successfully decoding the packet, or after a maximum number of retransmissions, or after a configured or preconfigured number of retransmissions; The TX UE relays a single HARQ feedback to the base station using a single PUCCH resource defined for a single DCI.

[0080] According to an embodiment (see, for example, claim 41), in a wireless communication system, The base station sends a single DCI to the TX UE indicating a HARQ-based transmission and including a single PUCCH location for a transmission and / or retransmission resource location; The TX UE transmits a plurality of SCIs with a retransmission resource location for each of the SCIs; The RX UE combines the received transmissions defined for a given SCI and transmits HARQ feedback based on the transmissions defined for the SCI; The TX UE relays a single HARQ feedback to the base station using a single PUCCH resource defined for a single DCI.

[0081] According to an embodiment (eg see claim 42), in a wireless communication system, a TX UE receives feedback for each SCI and stops transmitting the SCI when a RX UE responds with a positive ACK.

[0082] According to an embodiment (see, for example, claim 43), in a wireless communication system, The base station sends a single DCI to the TX UE indicating a HARQ-based transmission and including a single PUCCH location for a transmission and / or retransmission resource location; The TX UE transmits a plurality of SCIs with a retransmission resource location for each of the SCIs; The RX UE sends HARQ feedback for each of its transmissions; The TX UE relays a single HARQ feedback to the base station using a single PUCCH resource defined for a single DCI.

[0083] According to an embodiment (eg see claim 44), in a wireless communication system, a TX UE receives all feedback and stops retransmission and transmission of another SCI once the RX UE responds with a positive ACK.

[0084] According to an embodiment (see, for example, claim 45), in a wireless communication system, The base station sends a single DCI to the TX UE indicating a HARQ-based transmission and each DCI includes a single PUCCH location for a transmission and / or retransmission resource location; The TX UE transmits a plurality of SCIs with a retransmission resource location for each of the SCIs; The RX UE combines the received transmissions defined for the given SCI and transmits HARQ feedback based on the transmissions defined for the SCI; The TX UE receives the feedback for each SCI and relays the feedback to the base station using the PUCCH resource defined in the corresponding DCI; Now, when the RX UE receives feedback indicating that the packet has been successfully decoded, the base station stops sending DCI for that packet to the TX UE.

[0085] According to an embodiment (see, for example, claim 46), in a wireless communication system, The base station transmits a plurality of DCIs to the TX UE, each DCI indicating a HARQ-based transmission and including a single PUCCH location for a transmission and / or retransmission resource location; The TX UE transmits a plurality of SCIs with a retransmission resource location for each of the SCIs; The RX UE sends HARQ feedback for each of the transmissions; The TX UE receives all the feedback and relays the feedback to the base station using the PUCCH resource defined in the corresponding DCI; If the RX UE responds with a positive ACK, the TX UE stops the SCI, and in response to the positive feedback, the base station stops sending DCI for the packet to the TX UE.

[0086] According to an embodiment (see, for example, claim 47), in a wireless communication system, when a RX UE responds with a positive ACK, the TX UE stops the SCI, and in response to the positive feedback, the base station stops sending DCI for the packet to the TX UE.

[0087] According to an embodiment (see, for example, claim 48), in a wireless communication system, if the DCI provides resource allocations for an initial transmission and for one or more retransmissions and for a feedback channel, e.g., PUCCH, the base station disables all subsequent resource allocations, e.g., resource allocations for rescheduling the disabled resources to the same or another SL UE, for the initial transmission and for one or more retransmissions in response to an ACK for either from the TX UE.

[0088] According to an embodiment (see, for example, claim 49), in a wireless communication system, resources are allocated in an SCI based on information provided by a base station to a TX UE on a DCI: - if the frequency location or subchannel of the initial transmission and the frequency location or subchannel of one or more retransmissions are the same, the resource is a bitmap indicating the time slots in which retransmissions occur, for example in the form of a vector or in the form of an index that is mapped to a table in the RX UE that contains multiple bitmap vectors; - a timing offset that allows the RX UE to derive the time slot in which the retransmission occurs; is defined by at least one of - if the frequency location or subchannel of the initial transmission and the frequency location or subchannel of one or more retransmissions are different, the resource indicates the time and frequency location of the resource, e.g. in the form of an index that is mapped to a table in the RX UE that contains multiple time-frequency patterns; - a slot aggregation parameter indicating the number of aggregated slots; - DAI parameters, It is defined by one or more of the following:

[0089] According to an embodiment (see, for example, claim 50), in a wireless communication system, when using configured grants, if some grants include information about PUCCH and some do not include information about PUCCH, the TX UE: - sending feedback back to the base station using the grant including the PUCCH resource; - A grant that does not contain PUCCH resources is used for blind transmission.

[0090] According to an embodiment (see, for example, claim 51), in a wireless communication system, when using configured grants, the TX UE decides with which grant to transmit packets depending on the characteristics of the grant, e.g. the TX UE can use a grant for packets requiring high or low priority and / or reliability and / or latency depending on the quality of the resources.

[0091] According to an embodiment (see, for example, claim 52), in the wireless communication system, when using configured grants, the TX UE decides with which grant to transmit packets depending on the communication type, e.g. the TX UE can use a grant for packets related to broadcast, groupcast or unicast transmission depending on the resource status.

[0092] According to an embodiment (see, for example, claim 53), a wireless communication system comprises: UE is - a mobile terminal, or - Fixed terminal, or - Cellular IoT-UE, or - a vehicle UE, or - Vehicle Group Leader (GL) UE, or - an IoT or Narrowband IoT (NB-IoT) device, or - Ground vehicles, or - Air vehicles, or - Drones, or a mobile base station, or - Road Side Unit (RSU), or - Buildings, or - other items or devices, such as sensors or actuators, that are provided with network connectivity to enable communication using a wireless communication network; or - other items or devices, such as sensors or actuators, that are provided with network connectivity that allows them to communicate using a sidelink of a wireless communication network; or - any sidelink-capable network entity, and / or The base station - a macrocell base station, or - a small cell base station, or - a base station central unit, or - a base station distribution device, or - Road Side Unit (RSU), or - UE, or - Group Leader (GL), - Repeater, or - a remote radio head, or - AMF, or - SMF, or - a core network entity, or - a Mobile Edge Computing (MEC) entity, or - network slices in the NR or 5G Core context, or - a Transmit / Receive Point (TRP) enabling an item or device to communicate using a wireless communication network, the item or device being provided with network connectivity for communicating using the wireless communication network; Contains one or more of the following:

[0093] The present invention relates to a method for operating a transceiver in a wireless communication system, the wireless communication system including a plurality of user equipments (UEs) for communicating with each other using a side link (SL), the method comprising: For transmission over the sidelink of a packet, such as a data packet, the transceiver determines one or more transmission requirements for transmission over the sidelink of the data packet; transmitting one or more control messages in response to the determined one or more transmission requirements, the one or more control messages comprising: - a common control message containing parameters for HARQ-based transmissions using the sidelink and for blind or non-HARQ transmissions using the sidelink, or - a control message for a HARQ-based transmission including parameters for a HARQ-based transmission using the sidelink and a control message including parameters for a blind transmission or a non-HARQ transmission using the sidelink; a transmitting step including one or more of: (see, for example, claim 54).

[0094] The present invention relates to a method for operating a user equipment in a wireless communication system, the wireless communication system including a plurality of user equipments (UEs) for communicating with each other using a side link (SL), where the user equipments are transmitting user equipments (TX UEs) served by a base station of the wireless communication system, the method comprising: communicating with one or more receiving user equipments (RX UEs) using a sidelink; receiving, using the TX UE, one or more control messages, such as DCI, from a serving base station in response to one or more transmission requirements for transmission of a packet, such as a data packet, over a sidelink, the one or more control messages comprising: - a common DCI including parameters for HARQ-based transmissions using sidelink and blind or non-HARQ transmissions using sidelink, or - DCI for HARQ-based retransmissions containing parameters for HARQ-based transmissions using sidelink, or - DCI for non-HARQ retransmissions, including parameters for blind transmissions or non-HARQ transmissions using sidelink; a receiving step including one or more of: (see, e.g., claim 55).

[0095] The present invention relates to a method for operating a wireless communication system comprising one or more base stations and a plurality of user equipments (UEs) for communicating with each other using a side link (SL), the plurality of UEs including a transmitting UE (TX UE), the TX UE communicating with one or more receiving UEs (RX UEs) using the side link, the method comprising: providing service to a TX UE by a base station; determining, by the base station, one or more transmission requirements for transmission over the sidelink of a packet, such as a data packet, of the data packet; and transmitting, by the base station, one or more control messages to the TX UE in response to the determined one or more transmission requirements, the one or more control messages comprising: - a common control message including parameters for HARQ-based transmissions using the sidelink and blind or non-HARQ transmissions using the sidelink, or - a control message for HARQ-based retransmission comprising parameters for a HARQ-based transmission using sidelink, or - a control message for non-HARQ retransmissions, including parameters for blind transmissions or non-HARQ transmissions using sidelink; a transmitting step including one or more of: receiving, by the TX UE, one or more control messages from the base station; transmitting, by the TX UE, one or more control messages to the RX UE; and transmitting, by the TX UE, packets to the RX UE according to parameters indicated in the one or more control messages; (see, for example, claim 56).

[0096] The present invention relates to a method for operating a wireless communication system comprising one or more base stations as described above and a plurality of user equipments (UEs) communicating with each other using a side link (SL), the plurality of UEs including a transmitting UE (TX UE) as described above, the method comprising the steps of: Serving a TX UE by a base station, the TX UE communicating with one or more receiving UEs (RX UEs) using a sidelink; receiving, at the TX UE, one or more control messages from the base station, transmitting, at the TX UE, one or more control messages to the RX UE, and further transmitting, at the TX UE, packets to the RX UE according to parameters indicated in the one or more control messages; (see, for example, claim 57).

[0097] The present invention provides a non-transitory computer program product comprising a computer readable medium having stored thereon instructions which, when executed on a computer, perform the inventive method as described above (see, for example, claim 58).

[0098] Computer Program Products An embodiment of the present invention provides a computer program product comprising instructions which, when executed by a computer, cause the computer to carry out one or more methods according to the present invention.

[0099] The embodiments described herein relate to the idea of ​​enabling NR V2X to be enhanced to provide multiple blind and HARQ (re)transmissions in Mode 1 and Mode 2.

[0100] An embodiment provides a transceiver for a wireless communication system including a plurality of user equipments (UEs) communicating with each other using a sidelink (SL). For transmission of packets, such as data packets, using the sidelink, the transceiver determines one or more transmission requirements for transmission of the data packets using the sidelink. In response to the determined one or more transmission requirements, the transceiver transmits one or more control messages, the one or more control messages including one of the following: - a common control message containing parameters for HARQ-based transmissions using the sidelink and for blind or non-HARQ transmissions using the sidelink, or - a control message including parameters for a HARQ-based transmission using sidelink, or - A control message containing parameters for blind or non-HARQ transmissions using the sidelink.

[0101] In other words, based on the work in NR Uu, all DCI will include a PUCCH resource allocation in the feedback sent by the TX UE to the base station. When this is carried over to NR V2X, the described embodiment means that when a "blind" or "no HARQ" transmission is made, it only refers to the PC5 communication link. This means that the base station provides PUCCH resources for feedback on DCI (as required by the Uu work), but the base station can also instruct the TX UE to perform a blind or no HARQ transmission to the RX UE via the sidelink PC5.

[0102] Again, based on understanding of the progress of the specification, the information conveyed by the base station to the TX UE can be carried out in three possible ways: - The base station sending a DCI to the TX UE, e.g. using a dynamic grant, corresponding to one packet for sidelink transmission with feedback report to the base station. - The base station configuring resources for the TX UE via RRC signaling using a configured grant of type 1. - The base station configures resources for the TX UE via RRC signaling using a configured grant of type 2, where DCI is sent to activate / deactivate the grant.

[0103] Based on this understanding, ideas 1.2 and 1.3 state that although they are new parameters of DCI, they can also be used for RRC signaling. Similarly, idea 4 states that when the base station transmits DCI to the TX UE, it is also possible for the base station to transmit RRC signaling instead.

[0104] The described transceiver may be, for example, a UE or IoT device of a network and may operate in a network such as that described in FIG. 1, the network being adapted according to the described embodiments.

[0105] Idea 1

[0106] According to an embodiment, the one or more transmission requirements include one or more of the following: - Whether the packet requires HARQ feedback or blind retransmission, based on reliability requirements, e.g. QoS or channel conditions. - The number of retransmissions for the HARQ feedback scheme and / or the blind retransmission scheme, e.g. based on Packet Delay Budget (PDB) requirements. - Resources to use for transmission and retransmission using sidelink based on resource availability, e.g. resource congestion.

[0107] Alternatively or additionally, the transceiver may be configured to determine one or more transmission requirements in response to higher layer information about the packet, such as priority, PDB, or an acceptable packet error rate (PER), or other information related to reliability associated with the packet.

[0108] Elsewhere, in general terms, idea 1 relates to the Mode 1-DCI structure: the base station decides, which is up to the base station implementation (scheduler): - Whether the packet requires HARQ feedback or blind retransmission (based on reliability requirements). - The number of resubmissions for any of the above schemes (based on PDB requirements). - Resources used for (re)transmission by the TX UE (based on resource availability). - Resources used on PUCCH for TX UE to provide feedback to the base station (only for HARQ feedback). - The time gap between the PDCCH transmission containing DCI to the TX UE and the PUCCH transmission containing feedback from the TX UE to the base station. - The slot offset between DCI reception and the first sidelink transmission scheduled by DCI.

[0109] The parameters necessary to indicate the resources used for the PUCCH, the time gap between the DCI and the PUCCH, and the slot offset between the DCI reception and the first sidelink transmission scheduled by the DCI may be used, for example, according to 3GPP where they were discussed and agreed upon. The transceiver according to idea 1 may be implemented as a base station of a wireless communication system communicating with a transmitting UE (TX UE) using a Uu link, the TX UE communicating with one or more receiving UEs (RX UEs) using a sidelink, the transmitting UE and / or the receiving UE being in NR mode 1.

[0110] IDEA 1.1 - DCI Format

[0111] To further concretize idea 1, an embodiment related to a DCI format is described in relation to idea 1.1. The described transceiver, which is a base station, may be implemented such that the one or more transmission requirements further include one or more of the following: - Resources used on the PUCCH for TX UE to provide feedback to the base station in case of HARQ based transmission using sidelink. - The time gap between the PDCCH transmission containing DCI to the TX UE and the PUCCH transmission containing feedback from the TX UE to the base station. - The slot offset between DCI reception and the first sidelink transmission scheduled by DCI.

[0112] Related to this idea, but not limited to idea 1.1, the base station may be implemented to transmit one or more control information to the TX UE using one or more of the following: - Dynamic grant, where the base station sends DCI to the TX UE. - Type 1 configured grant, where the base station configures resources for the TX UE via RRC signaling. - Type 2 configured grant, where the base station configures resources for the TX UE via RRC signaling and DCI is sent to activate / deactivate the grant.

[0113] In other words, idea 1.1 is related to the DCI format. Once the base station makes the above-mentioned decision required to transmit a packet, it must convey this information to the TX UE via a new DCI format according to the embodiment. The embodiment proposes that the DCI format itself can be defined in one of two basic ways / means. - Using a single common DCI format. - Using different DCI formats for HARQ-based retransmissions and blind retransmissions.

[0114] To reduce the complexity of blind decoding at the UE side, using a single DCI format would be advantageous, but its size would be larger to accommodate both HARQ-based retransmissions and blind retransmissions.

[0115] Since HARQ-based retransmissions require additional parameters compared to blind retransmissions, it is not important whether a single DCI format or different formats are used, as the reporting is split into common parameters required for DCI. This is followed by a section describing the parameters used for each of the DCI formats.

[0116] IDEA 1.2 - COMMON PARAMETERS

[0117] According to idea 1.1, particularly in relation to the transceiver being implemented as a base station, each of the one or more control messages includes a common control message parameter, and the common control message parameter includes one or more of the following: - Resource location display, - Slot aggregation display, - the total number of retransmissions, - MCS level (Modulation Coding Scheme), - Max TX power, - Destination ID (of the receiver), - Cast type, - a transmission procedure indication, e.g. blind transmission or retransmission or HARQ enabled transmission, or - Priority display.

[0118] Optionally, the transceiver may be further implemented such that the resource location indication includes a time location and a frequency location of the retransmission and / or one or more retransmissions for a given maximum or allowable number of transmissions and / or retransmissions, such as 32 retransmissions in NR SL. If the frequency location or subchannel of the initial transmission and the one or more retransmissions is the same, the resource location indication may include at least one of the following: - a bitmap indicating the time slots in which retransmissions occur, e.g. in the form of a vector or in the form of an index mapped to a table in the TX UE containing multiple bitmap vectors; - A timing offset that allows the receiving UE to derive the time slot in which the retransmission occurs, up to the total number of possible retransmissions.

[0119] The timing offset can be defined in the DCI or configured via RRC configuration.

[0120] If the frequency locations or subchannels of the initial transmission and one or more retransmissions are different, the resource location indication may include a time-frequency pattern indicating the time and frequency location of the resource, e.g., in the form of an index that is mapped to a table in the TX UE that contains multiple time-frequency patterns.

[0121] According to an embodiment, the described TX UE is configured with a parameter, e.g. a PSSCH (Physical Sidelink Shared Channel)-aggregation factor parameter using RRC signaling, indicating the number of slots to be aggregated for transmission of the packet, e.g. for a large packet using multiple PSSCH regions between slots, and the slot aggregation indication may indicate only the frequency or subchannel and starting point of the first slot to use.

[0122] In other words, common DCI parameters may be commonly used in new DCI formats even if only one DCI format is defined or if multiple DCI formats are defined, e.g., two formats, one for HARQ-based retransmission and one for blind retransmission.

[0123] DCI Resource Location Indication

[0124] Considering that the maximum number of retransmissions has increased from 2 (LTE) to 32 (NR), it is necessary to define explicit time and frequency locations of the transmissions. To achieve this, the embodiments propose that resources can be defined in the DCI in at least one of the following ways: - If the frequency location (subchannel) of the initial and retransmission is the same, a bitmap indicating the time slots in which the retransmission occurs can be used. The bitmap is indicated in the DCI in the following form: Vector, or An index mapped to a table containing multiple bitmap vectors. - If the frequency location (subchannel) of the initial and retransmissions is the same, the time slot in which the retransmission occurs can be implicitly derived based on one or more of the following pre-configured, semi-statically configured or dynamically indicated parameters: ○ Number of (re)transmission positions. ○ Time offset between (re)transmission positions. If the frequency locations are different, a time-frequency pattern can be used to indicate the time and frequency locations of the resource, which can be in the form of an index mapped to a table containing multiple time-frequency patterns.

[0125] Slot Aggregation Display

[0126] The slot aggregation indication can be implemented independently of the resource location indication in the DCI. In case a large packet has to be transmitted, slot aggregation is possible, where multiple PSSCH regions between slots are used for the transmission of the packet. The number of slots to be aggregated in such a case is defined by the PSSCH-aggregation factor parameter and may be configured, for example, by RRC signaling. The timing offset between the aggregated slots, for example 0 to X slots, may be preconfigured or semi-statically configured, for example, by RRC signaling. In this case, the embodiment proposes that the DCI includes the following parameters: - The DCI only specifies the frequency (subchannel) and the starting point (explicit or implicit) of the first slot used for the transmission of the jumbo packet. Together with the configured PSSCH-aggregation factor parameter (for a dedicated ID), the UE knows how many slots the same resource allocation applies to, i.e. how many slots are aggregated.

[0127] The time offset between each aggregated slot may be pre-configured and / or configured using semi-static signaling, such as RRC.

[0128] IDEA 1.3 - Parameters for a common new DCI format

[0129] To keep the blind decoding effort low in Mode 1 TX, the network may decide to configure the UE with a single DCI format for scheduling SL transmissions. The embodiments related to this specification provide an apparatus and method for interpreting the values ​​of certain parameters for blind transmission and HARQ-based transmission.

[0130] According to an embodiment, the transceiver, such as implemented as a base station, is implemented such that the control messages are common control messages, similar to those listed above, including one or more of the following: - a retransmission type indication indicating whether one or more retransmissions on the sidelink are HARQ-based retransmissions or blind retransmissions; Downlink Allocation Index (DAI), A retransmission feedback resource location indication, for example on the PUCCH, indicating the resource location for transmitting feedback from the TX UE to the base station.

[0131] According to an embodiment, such a transceiver is adapted for the retransmission type indication to be: - is explicit and includes an explicit parameter indicating whether the transmitted packet uses HARQ-based retransmission or blind retransmission, or - implicit, by setting one or more predetermined parameters in the DCI to a pre-defined or default value; It may be implemented as follows.

[0132] According to an embodiment, in the case of an implicit retransmission type indication, the use of blind retransmission is - using non-numeric or default or pre-configured values ​​of parameters such as PUCCH resource indicator indicating the resource used for feedback from the TX UE to the base station, for example, on PUCCH, or a time gap such as PSSCH / PDCCH-HARQ timing indicator between the DCI and feedback, for example, on PUCCH, or - resource location indication for transmission and / or retransmission towards a set or resource pool of resources that does not include any resource of the PSFCH; and / or The use of HARQ-based retransmissions is - a resource location indication for transmission and / or retransmission indicating a set of resources or a resource pool including resources of the PSFCH; As shown by:

[0133] Alternatively or additionally, it may be indicated by use of a destination ID, priority information or a cast type, for example transmission resources for broadcast or a cast type such as a destination ID with no HARQ configured.

[0134] According to an embodiment, the DCI includes a downlink allocation index (DAI), which includes a counter DAI (cDAI) and a total DAI (tDAI). If the DCI is for blind retransmission using sidelink: - the counter DAI is not incremented or is assigned a default value or a predefined value, such as -1, and / or - DCI does not count towards your total DAI, and / or - the TX UE ignores the counter DAI, and / or - The counter DAI is incremented, but the counter DAI of subsequent DCIs for HARQ-based retransmissions is not incremented.

[0135] In other words, for indication of HARQ-based retransmission and / or blind retransmission, the DCI format may provide for both HARQ-based retransmission as well as blind retransmission and therefore parameters may be defined to inform the TE UE which type of retransmission to use for a particular packet.

[0136] ● An explicit parameter indicating whether the transmitted packet uses HARQ-based retransmission and / or blind retransmission.

[0137] This indication may be performed in an implicit manner or by setting certain default values ​​of other parameters of the DCI. ● Non-numeric or default or pre-configured values ​​of parameters, e.g. PUCCH resource indication indicating resources used on PUCCH, and / or implicit indication of the use of blind retransmission by using a time gap, e.g. PSSCH / PDCCH-HARQ timing indication between DCI and feedback, e.g. on PUCCH. ● Implicit display based on resource location parameters. o If the resource is located in a resource pool with a defined PSFCH (Physical Shared Feedback Channel), then the TX UE can assume that the transmitted packet will use HARQ based retransmission, unless otherwise specified. o If a resource is located in a resource pool that does not have a defined PSFCH, then the TX UE may assume that the transmitted packet will use blind retransmission, unless otherwise specified.

[0138] By using a HARQ reporting mechanism to report SL feedback to the base station in terms of the Downlink Allocation Index (DAI), the network can adopt a similar method to the Downlink Allocation Indication (DAI) for DCI scheduling SL grants, e.g., for dynamic HARQ-ASK codebooks.

[0139] NR uses a downlink allocation index DAI included in the DCI. The DAI field is divided into two parts: counter DAI (cDAI) and, in case of carrier aggregation, total DAI (tDAI). The counter DAI included in the DCI may indicate the number of scheduled downlink transmissions up to the point in time when the DCI is received in a carrier-first-time-second manner. The total DAI included in the DCI may indicate the total number of downlink transmissions across all carriers up to this point in time, i.e., the highest cDAI at the current point in time.

[0140] For these parameters used in the shared DCI format, the embodiment proposes the following. ● In case of a DCI that means a blind retransmission, the counter DAI is not incremented and / or the DCI is not counted in the total DAI. ○ It is also possible to assign a preset value to this parameter, e.g. a default value or -1. o A TX UE may choose to ignore this field. ● Alternatively, the counter DAI in case of blind transmission is incremented, but the counter DAI for subsequent SL grants with HARQ is not incremented.

[0141] Assigning a non-incremental or default value of DAI, as shown in FIG. 5, helps the UE to report correctly to the base station. For example, if the UE misses the DCI scheduling SL grant in PDCCH monitoring occasion #1, it can recover from PDCCH monitoring occasion #2 due to the presence of DCI with HARQ during which HARQ feedback is required. However, if the UE misses the DCI in PDCCH monitoring occasion #2, the UE cannot recognize the grant. This is not a critical issue, since there is no need to report this transmission to the base station and the UE must send an SR / BSR for the new grant anyway.

[0142] FIG. 5 shows a DAI procedure for scheduling HARQ and blind transmissions.

[0143] This procedure can be failsafe if the UE misses the DCI for HARQ.

[0144] PUCCH Indication

[0145] In the case of blind retransmission, a single DCI can transmit all retransmission positions, or the base station can choose to transmit multiple DCIs that include a subset of the retransmission resource positions with positions indicated in the above method.

[0146] For HARQ-based retransmission, each DCI sent to the TX UE may also indicate a PUCCH resource, and the TX UE may forward the HARQ feedback received from the RX UE to the base station. It is not effective to allocate PUCCH resources for each retransmission in a single DCI, since the overhead and size of the DCI will increase.

[0147] Therefore, embodiments propose that the number of retransmission resource locations indicated in the DCI can be quantized to be a multiple of the total number of retransmissions associated with a particular packet. For each DCI, the PUCCH locations may be defined in one of the following ways: Each DCI contains a single PUCCH position for a total of (MxP) retransmissions as shown in FIG. In this method, each DCI contains only one subset of retransmission resource locations (M) and PUCCH locations. o A TX UE receiving this DCI is expected to send an SCI to the RX UE with the resource location. o Now the RX UE attempts to receive all M transmissions at the defined resource locations and then soft-combine the transmissions. o Sends an ACK / NACK to the TX UE based on whether the RX UE was able to decode the packet correctly or not. o It is then relayed to the base station by using the single PUCCH position defined in the DCI. This procedure is repeated P times until the RX UE correctly decodes the packet or the maximum number of retransmissions (MxP) is reached. Each DCI may include multiple PUCCH resources corresponding to respective retransmission resource positions as shown in FIG. o According to this method, the DCI contains a subset of retransmission resource locations and PUCCH locations for each resource location. o Indication of PUCCH position for the respective feedback can be in an implicit or explicit manner, e.g. ● Explicit method: DCI may include all PUCCH positions of each (re)transmission. ● Implicit method 1: The DCI may include the PUCCH location corresponding to the first transmission. For subsequent transmissions, the TE UE may assume a time gap between the resource locations of these transmissions and derive the respective PUCCH locations accordingly, e.g. as shown in Fig. 8 . ● DCI may also derive the PUCCH resource location based on the time gap between the initial transmission location and the PUCCH resource location, and apply a predefined time gap for subsequent retransmission resource locations. In the first DCI, the base station indicates a HARQ-timing indication indicating a slot in which the first HARQ-ACK is notified, and a PUCCH resource indication (PRI) 316 indicating one of a plurality of configured PUCCH configurations to be used for PUCCH transmission in the slot. 1 Also specify. ● In the implicit approach, the timing refers only to the first PUCCH resource and subsequent PUCCH resources are determined by applying the same offset to the PUCCH resource that is also applied to the PSSCH transmission. ● Other parameters such as PRI are also carried over from the first PUCCH for HARQ-ACK notification. Thus, FIG. 8 shows the allocation of subsequent PUCCH resources 316 based on the first PUCCH. 2 and 316 3 This shows the implicit derivation of For up to 32 DCIs, allowing a single SCI to indicate up to 4 transmissions may require up to 4 SCIs. The implicit method therefore allows a reduction in the messages transmitted.

[0148] The procedure followed by a TX UE on receiving the DCI may be performed in one of two ways: o TX UEs are expected to send a single SCI for all resource locations with an indication that they have to send feedback for each of their transmissions. o It is expected that the TX UE will transmit multiple SCIs containing different subsets of the resource locations described in the DCI and specifying for each transmission feedback has to be sent.

[0149] The RX UE may thereby provide feedback for each of the transmissions. Upon receiving feedback from the RX UE for each transmission, the TX UE may provide feedback to the base station regarding the PUCCH resources for the transmission, which are implicitly derived or explicitly indicated in the DCI.

[0150] Regarding idea 1.3, in the case of blind retransmission and HARQ-based retransmission, the transceiver may indicate some or all of the transmission and / or retransmission positions, and in the case of only HARQ-based retransmission, the retransmission position indication in the DCI sent to the TX UE may indicate PUCCH resources on which the TX UE can forward HARQ feedback received from the RX UE to the base station.

[0151] According to an embodiment, such a transceiver may be implemented such that, in the case of HARQ based retransmissions, the retransmission position indication in the DCI indicates the number of transmission and / or retransmission resource positions, where the number of transmission and / or retransmission resource positions is MxP, where MxP is the maximum or allowable number of transmissions and / or retransmissions for a packet, e.g., not to exceed 32 retransmissions for NR, where M is the number of transmission and / or retransmission resource positions contained in a single DCI, and where P is the number of DCIs transmitted for a given packet.

[0152] According to an embodiment, such a transceiver may be implemented such that the DCI includes a single PUCCH location for M transmission and / or retransmission resource locations, where the transceiver: - transmitting DCI comprising M transmission and / or retransmission resource locations and only one PUCCH location; - receiving, in response to the DCI, a composite feedback for the RX UE from the TX UE for all M transmissions by using a single PUCCH location; - repeat transmission of the DCI P times until feedback indicates successful decoding of the packet at the RX UE or until a maximum number of retransmissions MxP is reached; It is configured as follows.

[0153] According to an embodiment, such a transceiver may be implemented such that the DCI includes a plurality of PUCCH positions for each transmission and / or retransmission resource position, where the transceiver: - transmitting DCI comprising M transmission and / or retransmission resource locations and one PUCCH location for each transmission and / or retransmission resource location; - receiving, in response to the DCI, feedback for the RX UEs for each of the M transmissions by using a PUCCH position for transmission and / or retransmission from the TX UE; - Repeat transmission of the DCI P times until feedback indicates successful decoding of the packet at the RX UE or until the maximum number of retransmissions MxP is reached.

[0154] According to an embodiment, such a transceiver may be implemented such that the DCI includes a plurality of PUCCH locations for the transmission and / or retransmission resource locations but not each of the transmission and / or retransmission resource locations, and the transceiver: - transmitting DCI comprising MxP transmission and / or retransmission resource locations and a PUCCH location after every M transmission and / or retransmission resource location; - receiving feedback for RX UEs from TX UEs for every M-th transmission by using a PUCCH position for transmission and / or retransmission in response to the DCI; - Continue receiving feedback from the TX UE every M-th transmission until the feedback indicates successful decoding of the packet at the RX UE or until the maximum number of retransmissions MxP is reached.

[0155] According to an embodiment, the DCI is an explicit or implicit indication. In the case of an explicit indication, the DCI may include all PUCCH locations for the transmission and / or retransmission. In the case of an implicit indication, the DCI may include the PUCCH resource locations corresponding to the first transmission. For the second and subsequent transmissions and / or retransmissions, the TX UE may indicate the PUCCH locations for the second and subsequent transmissions and / or retransmissions as: - using the time gap between resource positions for the second and / or subsequent transmissions and / or retransmissions and applying the given time gap starting from the PUCCH resource position for the first transmission, or - deriving using a time gap between the first transmission position and the PUCCH resource position and applying the given time gap to the second and subsequent retransmission resource positions; At least one of the following is performed.

[0156] According to an embodiment, the DCI may indicate, either explicitly or implicitly: In the first DCI, the transceiver indicates: - a HARQ-Timing Indicator pointing to the slot in which the first HARQ-feedback is reported, and - A PUCCH Resource Indication (PRI) indicating one of multiple configured PUCCH configurations to use for PUCCH transmission in the slot.

[0157] By applying the same offset to the PUCCH resources as is applied to the PSSCH transmission, one or more slots for the second and subsequent HARQ-feedback are determined.

[0158] Thus, in response to the common DCI, the TX UE may be expected to transmit at least one of a single SCI with all resource locations with an indication of feedback for each of the transmissions, or to transmit multiple SCIs with another subset of the resource locations described in the DCI and specify that feedback must be transmitted for each of the transmissions. Upon receiving feedback from the RX UE for each transmission, the TX UE may provide feedback to the base station on the PUCCH resources implicitly derived or explicitly indicated in the DCI for the transmission. In response to the common DCI, the TX UE may be expected to transmit a single SCI as an SCI with at least two stages. That is, the PSCCH for one transmission may be split into two SCIs. The SCIs may be frequency multiplexed (FDMed) or time multiplexed (TDMed) first and second stage SCIs.

[0159] IDEA 1.4 - Individual DCI format parameters

[0160] Apart from the above mentioned common parameters, embodiments propose that the DCI format for HARQ based transmissions may include parameters indicating the resources used for PUCCH, the time gap between DCI and PUCCH, and the slot offset between DCI reception and the first sidelink transmission scheduled by DCI. The DCI for blind transmissions may not include these parameters related to HARQ feedback. In this case, separate indications for HARQ based transmissions and blind transmissions are also not necessary and can therefore be omitted. A transceiver according to such embodiments may be based on additional parameters including parameters indicating one or more of the following: - resources used by the PUCCH, - the time gap between DCI and PUCCH; - The slot offset between DCI reception and the first sidelink transmission scheduled by DCI.

[0161] Idea 2: Strengthening the HARQ reporting procedure

[0162] The embodiments relate to HARQ reporting of blind transmissions. Such embodiments can address issues that may arise in different scenarios. In one scenario, the base station has full control over all mode 1 UEs and explicitly indicates for each of the transmissions whether or not HARQ is used. Furthermore, as explained in relation to the other embodiments, the same DCI format is used for HARQ and no HARQ / blind transmissions. However, unlike the previous section, the embodiments address ensuring the correct reception of these DCIs as well. Therefore, the embodiments propose that these are also protected using the DAI used for HARQ-based transmissions. However, in this case, it is necessary to specify what the UE reports for no HARQ / blind transmissions to the base station.

[0163] A transceiver according to such an embodiment may be implemented in view of the DCI including a Downlink Allocation Index (DAI), where the DAI includes a counter DAI (cDAI) and a total DAI (tDAI). The counter DAI is incremented if the DCI is for a HARQ-based retransmission and if the DCI is for a blind retransmission. The transceiver increments the counter DAI for DCIs indicating a reported blind retransmission from a TX UE for a no HARQ transmission or a blind transmission.

[0164] According to an embodiment, if the DCI for a no HARQ or blind transmission is correctly received at the TX UE, such transceiver may be configured to receive an ACK from the TX UE on the designated PUCCH resource to signal correct reception of the DCI. Since correct reception is assumed, the transceiver may decide not to schedule a new resource for this transmission. If the DCI for a no HARQ or blind transmission is incorrectly received at the TX UE, the transceiver may be configured to receive a NACK from the TX UE on the designated PUCCH resource. The transceiver may schedule a new grant for the same transmission in this case.

[0165] According to idea 2, the transceiver may be configured to receive an ACK from the TX UE when the TX UE determines that all allowable transmissions and / or retransmissions for the packet are completed. In response to the ACK, the transceiver may stop allocating further resources for the packet, independent of feedback on the PSFCH. Alternatively or additionally, the transceiver may be configured to receive an explicit parameter indicating that all allowable transmissions and / or retransmissions for the packet are completed, and the explicit parameter may be configured to cause the transceiver to stop allocating further resources for the packet, independent of feedback on the PSFCH.

[0166] The user equipment according to idea 2 may be implemented accordingly. The control message may be a common DCI. The DCI may include a downlink allocation index (DAI), including a cDAI that is incremented when the DCI is a HARQ-based retransmission and when the DCI is a blind retransmission. The TX UE is configured to send an ACK to the base station on the corresponding PUCCH resource when the DCI for no HARQ transmission or blind transmission is successfully received.

[0167] Such a user equipment may be configured such that if unexpected traffic arrives before the HARQ-ACK of a no HARQ transmission is reported to the base station and the TX UE needs more resources, the TX UE may be configured to reuse the HARQ-ACK feedback for the blind transmission as a Scheduling Request (SR) to inform the base station that more resources are needed, e.g. by sending a NACK for the blind transmission in case more resources are needed. This procedure may be applied, e.g., when the SR field is not present in the corresponding PUCCH resource.

[0168] In other words, in another scenario, the base station may not explicitly specify in the DCI whether HARQ should be used for a particular transmission, and the UE may decide autonomously based on QoS or depending on the UE implementation. However, in this case, the base station must specify PUCCH resources for HARQ-ACK reporting, since it does not know whether HARQ was used or not. Therefore, feedback for HARQ-based retransmissions and blind retransmissions may be multiplexed on the same PUCCH resources. Two different operations of the UE for determining HARQ feedback for blind transmissions are described in connection with the following embodiments. ● For example, as shown in Fig. 9 , which shows a schematic diagram of multiplexing HARQ-based and blind / HARQ-free transmissions in a single PUCCH, if the TX UE correctly receives the corresponding DCI, it can simply report an ACK of the HARQ-free / blind transmission on the specified PUCCH resource to the base station, to inform the base station that no further resources are required for the given transmission. ● If the TX UE does not receive the DCI correctly, i.e. DCI318 2 If you missed it, DCI318 2 Related feedback 322 2 As shown in Fig. 1, regardless of HARQ-based transmission or blind transmission (e.g., DCI318 3The DAI will determine that it has missed the DCI and will report a NACK. ● This allows the gNB to detect missed DCI for blind transmissions and schedule a new grant for the same transmission accordingly. In a different embodiment, unexpected traffic may arrive before the HARQ-ACK for the no-HARQ transmission is reported to the base station, and the UE may need more resources. In this case, the UE may reuse the HARQ-ACK feedback for the blind transmission as a Scheduling Request (SR) to inform the base station that it needs more resources. This is done by sending a NACK for the blind transmission when it needs more resources. In another embodiment, this procedure is only applied if the SR field is not present in the specified PUCCH resource.

[0169] Displaying maximum retransmissions

[0170] If the base station does not control each of the transmissions, it may not be able to keep track of how many retransmissions have already been performed for a particular packet. In this case, the TX UE simply reports again on the PUCCH what the RX UE has sent to the base station on the PSFCH. This may be problematic if the RX UE reports a NACK again after all 32 retransmissions have been performed. In this case, the base station will allocate resources for further retransmissions without knowing that 32 retransmissions have already been performed. This leads to a waste of resources, since the UE may not have enough data to use this resource.

[0171] Therefore, the embodiment proposes the following solution. 1. The TX UE has specific knowledge of how many retransmissions it has already performed for a particular TB or packet. If the TX UE determines that all 32 retransmissions have already been performed, it will report an ACK to the base station in any case. The same applies if the RX UE sends a NACK on the PSFCH. In this way, resource waste can be reduced. 2. The RX UE has specific knowledge of how many retransmissions it has already performed for a particular TB or packet. If the RX UE determines that all 32 retransmissions have already been performed, it will report an ACK to the TX UE in any case, even if the TB or packet could not be successfully decoded. In this way, resource waste can be reduced. 3. There can also be an explicit parameter indicating that all 32 retransmissions have been performed, and if a NACK is sent from the RX UE to the TX UE, the base station can determine that the packet could not be decoded successfully.

[0172] Idea 3: Multiple HARQ-based simultaneous transmissions

[0173] A base station can schedule multiple DCIs corresponding to HARQ-based transmissions of different packets, some of which can use slot aggregation to transmit larger packets, while at the same time some DCIs can be used for packets that require only one transmission (no retransmissions - one-shot transmission).

[0174] According to the general idea of ​​the present embodiment, a user equipment (TX UE) of a wireless communication system is provided. The wireless communication system includes a plurality of user equipments (UE) for communicating with each other using a side link (SL), where the user equipment is a transmitting user equipment (TX UE) served by a base station of the wireless communication system, and communicates with one or more receiving user equipments (RX UE) using the side link. For transmitting a packet such as a data packet using the side link, the TX UE receives one or more control messages such as DCI from the serving base station according to one or more transition requirements for transmitting the data packet, and the one or more control messages include: - any common DCI including parameters for HARQ-based transmissions using sidelink and blind or non-HARQ transmissions using sidelink, or - two different DCIs - a DCI for HARQ-based retransmissions comprising parameters for HARQ-based transmissions using sidelink and / or a DCI for non-HARQ retransmissions comprising parameters for blind transmissions or non-HARQ transmissions using sidelink. Optionally, the serving base station may comprise or be a transceiver, as described in connection with other embodiments.

[0175] That is, the transceiver may transmit one or more of the following: - a common control message containing parameters for HARQ-based transmissions using the sidelink and for blind or non-HARQ transmissions using the sidelink, or - a control message for HARQ-based retransmission containing parameters for a HARQ-based transmission using sidelink, or - A control message for non-HARQ retransmissions containing parameters for blind transmissions or non-HARQ transmissions using sidelink.

[0176] According to an embodiment, the TX UE may be configured to receive from the base station one or more common DCIs indicating slot aggregation and one or more DCIs for packets that require only one or one-shot transmission. If slot aggregation on the sidelink is active, the TX UE is configured to apply the same HARQ timeline for transmissions for which the TX UE has to send a HARQ-ACK to the base station. PSSCH aggregation may be always active or may be activated by the base station using RRC or DCI signaling, and the HARQ timeline is the maximum slot aggregation that is set or activated for all transmissions. The HARQ timeline is the time taken from the time the TX UE receives the DCI to the time the TX UE is ready to send feedback to the base station after it receives and decodes the transmission.

[0177] In other words, since a UE is communicating with multiple UEs in parallel and the slot aggregation scheme is used only for a subset of the communication links, the timing of HARQ reports to the base station becomes complicated due to different timing requirements for one-shot and slot aggregated transmissions.

[0178] In Uu, the processing time is always applied from the end of the PDSCH or PUSCH to determine the earliest time for HARQ reporting. If the timeline is not met, the UE does not report to the base station. However, in Uu, the UE is configured with an aggregation factor (a specific K for K repetitions) and this parameter is applied globally to all transmissions, so there is no mismatch even if the UE misses a DCI. However, in SL, a mixed operation of slot aggregated transmissions and one-shot transmissions is expected. This is mainly an issue when the UE misses a DCI. In this case, it is not known whether it is a slot aggregated transmission or a grant for one-shot transmission, and the processing timeline cannot be determined properly.

[0179] Single throughput for SL HARQ

[0180] If slot aggregation is activated for a TX UE, the embodiments propose to apply the same HARQ timeline for all transmissions for which the TX UE has to send a HARQ-ACK to the base station. PSSCH aggregation may be always active or may be activated by the base station using RRC or DCI signaling.

[0181] The DCI with SL grant may specify the timing of the HARQ-ACK report, e.g., the slot where a PUCCH from the TX UE is expected. However, the UE will not report a HARQ-ACK in the specified slot if the HARQ timeline is not met, e.g., if the specified slot is earlier than the HARQ timeline. According to an embodiment, the UE may apply for all transmissions the HARQ timeline of the maximum slot aggregation configured / activated in the UE. Even if HARQ feedback for one-shot transmissions is already available in the specified slot but does not meet the configured HARQ timeline of the maximum aggregation, the UE will not report a HARQ-ACK in the specified PUCCH. This can be seen in Figure 10, which shows a schematic block diagram to explain the timeline separation process.

[0182] In another embodiment, the single processing capability may vary depending on the configuration, for example, whether the UE is configured with slot aggregation or not, or based on the resource pool configuration (PSFCH periodicity).

[0183] Idea 4: Mode 1 HARQ retransmission procedure and SCI structure

[0184] According to an embodiment according to idea 4, a wireless communication system as shown in Fig. 1 is adapted to include one or more base stations and a plurality of user equipments (UEs) communicating with each other using a sidelink (SL), the plurality of UEs including a transmitting UE, the transmitting UE communicating with one or more receiving UEs using the sidelink. The base station is for serving the TX UE. For transmission of packets, such as data packets, using the sidelink, the base station determines one or more transmission requirements for the transmission of the data packets using the sidelink, and in response to the determined one or more transmission requirements, the base station transmits one or more control messages to the TX UE, the one or more control messages including one or more of the following: - a common control message including parameters for HARQ-based transmissions using the sidelink and blind or non-HARQ transmissions using the sidelink, or - a control message for HARQ-based retransmission comprising parameters for a HARQ-based transmission using sidelink, or - A control message for non-HARQ retransmissions containing parameters for blind transmission or non-HARQ transmission using sidelink.

[0185] The TX UE may be configured to receive one or more control messages from the base station, transmit the one or more control messages to the RX UE, and further transmit packets to the RX UE according to parameters indicated in the one or more control messages.

[0186] According to idea 4, one or more base stations of the wireless communication system may be according to another embodiment described herein. Alternatively or additionally, a plurality of user equipments of the wireless communication system may be implemented as described in relation to another embodiment described herein. The TX UE may be configured to receive one or more control messages from the base station, send one or more control messages to the RX UE, and further send packets to the RX UE according to parameters indicated in the one or more control messages.

[0187] In other words, the previous section described the possibility of transmitting a single or multiple DCIs including retransmission resource locations based on whether the TX UE transmits an SCI to the RX UE. Here, the RX UE is expected to decode the transmission and determine whether it was successfully decoded or not. Based on this determination, the RX UE transmits HARQ feedback to the TX UE.

[0188] Idea 4.1 - Periodicity of HARQ Feedback Sent from RX UE to TX UE

[0189] According to the embodiment described in relation to Fig. 11, the base station of the wireless communication system according to the embodiment may be configured to transmit a single DCI 318 to the TX UE indicating the HARQ-based transmission, transmission and / or retransmission resource location and a single PUCCH location. The TX UE may be configured to transmit a single SCI 324 to the RX UE. The RX UE may be configured to transmit a single HARQ feedback 326 to the TX UE, which may be configured to combine all received retransmissions 328 and transmit HARQ feedback only after successful decoding of the packet or after a maximum number of retransmissions. The TX UE relays the single HARQ feedback 332 to the base station using the single PUCCH resource defined in the single DCI 318.

[0190] According to an embodiment described in connection with Fig. 12, the wireless communication system described herein is implemented such that the base station configures the TX UE to transmit a single DCI 318 described in connection with Fig. 11 to the TX UE, the single DCI 318 indicating a HARQ based transmission and including a single PUCCH location for the transmission and / or retransmission resource location. The TX UE is configured to transmit a single SCI 324 of Fig. 11 to the RX UE. The TX UE receives multiple HARQ feedbacks 326 from the RX UE. 1 From 326 N , but only notifies the base station if the RX UE successfully decodes the packet. The TX UE stops retransmissions once the RX UE responds with a positive HARQ, i.e., further data signals 334 can be omitted after the feedback 326 from the RX UE is interpreted as a positive ACK.

[0191] A TX UE may schedule a CBG-based transmission to a RX UE using a single SCI, e.g. including several code blocks grouped into a CBG, and expect multiple feedbacks, e.g. one pair per CBG.

[0192] In other words, according to the embodiment proposed in relation to FIG. 11, the transmission process of HARQ feedback can be defined as a single DCI being sent from the BS to the TX UE, followed by a single SCI being sent from the TX UE to the RX UE, thereby providing a single HARQ feedback from the RX UE to the TX UE. ● The RX UE will combine all received retransmissions and send HARQ feedback only after successful decoding of the packet or after the maximum number of retransmissions. o It is then associated by the TX UE to the base station using a single PUCCH resource defined in a single DCI 318.

[0193] According to the embodiment described in relation to FIG. 12 and sometimes referred to as single DCI, single SCI and multiple HARQ feedback per transmission, the following occurs: ● The TX UE receives multiple HARQ feedbacks from the RX UE. 1 From 326 N However, the base station is only notified if the RX UE successfully decodes the packet. ● A TX UE may use a single SCI 324 to schedule CBG-based transmissions via RX UEs, i.e. transmissions involving multiple code blocks grouped into a CBG (Code Block Group). o In this case the TX UE expects multiple feedbacks, i.e. one for each CBG.

[0194] According to an embodiment, sometimes referred to as single DCI, multiple SCIs, and single HARQ feedback shown in Fig. 13, a wireless communication system is implemented such that the base station is configured to transmit a single DCI to the TX UE indicating a HARQ-based transmission and including a single PUCCH location for transmission and / or retransmission resource locations. The TX UE is configured to transmit multiple SCIs with a retransmission resource location for each SCI to the RX UE. The RX UE is configured to combine all received retransmissions and transmit HARQ feedback only after successful packet decoding or after a maximum number of retransmissions or after a configured or preconfigured number of retransmissions. The TX UE is configured to associate the single HARQ feedback to the base station using the single PUCCH resource defined for the single DCI.

[0195] In other words: • The TX UE will transmit multiple SCIs 324, each with a retransmission resource location. ● The RX UE will combine all received retransmissions and transmit HARQ feedback 326 only after either successfully decoding the packet, or after a maximum number of retransmissions, or after a configured or pre-configured number of retransmissions. ● It is then associated by the TX UE to the base station using a single PUCCH resource defined in a single DCI.

[0196] According to an embodiment described in relation to Fig. 14, the wireless communication system is implemented such that the base station is configured to transmit a single DCI 318 to the TX UE indicating the HARQ transmission and including a single PUCCH location for the transmission and / or retransmission resource location. The TX UE transmits multiple SCIs 324 with retransmission resource locations for each of the SCIs. The RX UE is configured to combine the received transmissions defined for a given SCI and transmit HARQ feedback based on the transmissions defined for that SCI, i.e. up to P HARQ feedbacks. The TX UE is configured to receive feedback for each SCI and stop transmitting the SCI when the RX UE responds with a positive ACK in one of the feedbacks 326. The TX UE relays the single HARQ feedback 332 to the base station using the single PUCCH resource defined for the single DCI 318.

[0197] In other words, FIG. 14 illustrates the following scenarios, which may be termed single DCI, multiple SCIs, and multiple HARQ feedback per SCI. ● The TX UE will transmit multiple SCIs, each with a retransmission resource location. ● The RX UE will combine the received transmissions defined for a given SCI and transmit HARQ feedback based on the transmissions defined for that SCI. ● The TX UE will receive feedback for each SCI and will stop transmitting SCIs once the RX UE responds with a positive ACK. ● It is then associated by the TX UE to the base station using a single PUCCH resource defined in a single DCI.

[0198] According to an embodiment illustrated in connection with Fig. 15, which may be referred to as single DCI, multiple SCIs, and multiple HARQ feedback per retransmission, a base station of a wireless communication system is configured to transmit a single DCI 318 to a TX UE indicating a HARQ-based transmission and indicating a single PUCCH location for transmission and / or retransmission resource location. The TX UE is configured to transmit multiple SCIs 324 with retransmission resource locations for each of the SCIs. The RX UE is configured to transmit HARQ feedback for each of the transmissions. The TX UE is configured to receive all feedback and stop retransmissions and transmission of another SCI once the RX UE responds with a positive ACK, i.e., if one of the messages 326 contains a positive feedback. The TX UE is configured to relay the single HARQ feedback to the base station using a single PUCCH resource defined for the single DCI.

[0199] In other words, according to the embodiment: ● The TX UE will transmit multiple SCIs, each with a retransmission resource location. ● The RX UE will send HARQ feedback for each transmission. ● The TX UE will stop transmitting SCI once it has received all feedback and the RX UE has responded with a positive ACK. ● It is then associated by the TX UE to the base station using a single PUCCH resource defined in a single DCI.

[0200] According to an embodiment described in relation to Fig. 16 and sometimes referred to as multiple DCIs, multiple SCIs (for each DCI), multiple HARQ feedbacks per SCI, the wireless communication system is implemented such that the base station is configured to transmit multiple DCIs to the TX UEs, each DCI indicating a HARQ based transmission and each DCI including a single PUCCH location for transmission and / or retransmission resource location. The TX UE is configured to transmit multiple SCIs with a retransmission resource location for each of the SCIs. The RX UE is configured to combine received transmissions defined for a given SCI and transmit HARQ feedback based on the transmissions defined for that SCI. The TX UE is configured to receive feedback for each SCI and associates the feedback to the base station using the PUCCH resource defined for the corresponding DCI. If feedback is received indicating successful decoding of a packet by the RX UE, the base station is configured to stop transmitting DCIs to the TX UE for that packet.

[0201] In other words, the embodiment comprises: ● The base station transmits multiple DCIs, each of which includes a retransmission resource location, which is transmitted from the TX UE to the RX UE via the SCI. ● The RX UE will combine the received transmissions defined for a given SCI and send HARQ feedback based on the transmissions defined for that SCI. ● The TX UE receives feedback for each SCI and then associates with the base station using the PUCCH resource defined in the corresponding DCI. ● Once the RX UE successfully decodes the packet, it will relay it to the base station and stop sending DCI for that packet to the TX UE.

[0202] According to an embodiment described in connection with FIG. 17 and sometimes referred to as multiple DCIs, multiple SCIs (for each DCI), multiple HARQ feedbacks per retransmission, the wireless communication system is implemented such that the base station is configured to transmit multiple DCIs to the TX UE indicating a HARQ based transmission, each DCI including a single PUCCH location for a transmission and / or retransmission resource location. The TX UE is configured to transmit multiple SCIs including a retransmission resource location for each of the SCIs. The RX UE transmits HARQ feedback for each of the transmissions. The TX UE is configured to receive all feedback and relays the feedback to the base station using the PUCCH resource defined in the corresponding DCI. When the RX UE responds with a positive ACK, the TX UE is configured to stop the SCI, and in response to the positive feedback, the base station is configured to stop the DCI transmission to the TX UE for that packet.

[0203] In other words, the embodiment can be described as follows. ● The base station transmits multiple DCIs, each DCI containing a retransmission resource location, which is transmitted from the TX UE to the RX UE via the SCI. ● The RX UE will send HARQ feedback for each transmission. ● The TX UE shall be configured to receive all feedback and shall relay it to the base station using the PUCCH resources defined in the corresponding DCI. ● The TX UE will stop transmitting the SCI once the RX UE responds with a positive ACK, which will be relayed to the base station, and the base station will stop transmitting the DCI to the TX UE for that packet.

[0204] If the DCI provides resource allocations for the initial transmission and another retransmission with a feedback channel, e.g. PUCCH, respectively, an ACK sent from the TX UE to the GNB for one of these transmissions invalidates the subsequent resource allocation. For example, if the DCI schedules four transmission positions distributed in time, the TX UE can first use the resource allocation that is first in time to perform the initial transmission. Assuming that the RX UE responds with a NACK, the TX UE reports an ACK to the GNB and uses the next resource in time to perform the retransmission. If the RX UE then reports an ACK, the TX UE reports an ACK to the GNB and does not use the following two resources that foresaw a possible retransmission. This can be rescheduled by the GNB to the same or another SL UE.

[0205] IDEA 4.2-SCI Structure

[0206] According to an embodiment, the wireless communication system may be implemented such that, based on information that the base station provides to the TX UE on the DCI, resources are defined in the SCI by one or more of the following: - if the frequency location or subchannel of the initial transmission and the frequency location or subchannel of one or more retransmissions are the same, the resource is defined by at least one of the following: a bitmap indicating the time slot in which the retransmission occurs, for example in the form of a factor or in the form of an index that maps to a table in the RX UE that contains multiple bitmap factors; o A timing offset that allows the RX UE to derive the time slot in which the retransmission occurs. - if the frequency location or subchannel of the initial transmission and the frequency location or subchannel of one or more retransmissions are different, the resource indicates the time and frequency location of the resource, e.g. in the form of an index mapped to a table in the RX UE containing multiple time-frequency patterns; - a slot aggregation parameter indicating the number of aggregated slots; - DAI parameters, Thus, it is defined.

[0207] Idea 5: Mode 2: Blind retransmission and HARQ retransmission procedures

[0208] To further specify the transceiver according to the general idea, according to an embodiment, the transceiver may be implemented as a transmitting UE that communicates with one or more receiving UEs using a sidelink. The transmitting UE and / or the receiving UE may operate in NR mode 2. The one or more control messages are sidelink control information messages (SCI messages) that include sidelink control information (SCI).

[0209] In other words, in Mode 2, the TX UE is responsible for making decisions regarding the following aspects: ● Whether the packet requires HARQ feedback or blind retransmission (based on reliability requirements). ○ QoS, channel conditions, etc. ● The number of resubmissions in any of the above schemes (based on PDB requirements). ● Resources used for (re)transmission by the TX UE (based on resource availability).

[0210] The TX UE receives higher layer information about the packet, which may provide parameters such as priority, PDB, and acceptable packet error rate (PER) (related to the reliability attached to the packet). The embodiment proposes that the TX UE considers and uses this higher layer information to make the above decision. Based on the TX UE's sensing result, it must also consider the resource congestion situation at a certain time. The TX UE can transmit the priority attached to the packet on the SCI so that the RX UE can align accordingly.

[0211] Idea 6: Set Grants

[0212] According to an embodiment, the wireless communication system described herein may be implemented to use configured grants. When using configured grants, if some grants include information about PUCCH and some do not, the TX UE may be configured as follows: - sending feedback back to the base station using the grant including the PUCCH resource; - A grant that does not contain PUCCH resources is used for blind transmission.

[0213] According to an embodiment, such a wireless communication system may be configured such that when using configured grants, the TX UE decides on which grant to transmit packets depending on the characteristics of the grant, e.g. the TX UE may use a grant for packets requiring high or low priority and / or reliability and / or latency depending on the quality of the resources.

[0214] Such a wireless communication system may be implemented such that when using configured grants, the TX UE decides with which grant to transmit packets depending on the communication type, e.g., the TX UE may use grants for packets related to broadcast, groupcast or unicast transmission depending on resource conditions.

[0215] In other words, in the configured grants, some grants may contain information about PUCCH, and some may not. The ones containing PUCCH resources are used by the TX UE to send feedback back to the base station. The grants without them can be used for blind transmission. Since the base station can provide multiple configured grants to the TX UE, and the TX UE can use any of these grants to transmit TB, the UE decides which grant to use based on the characteristics of the grants. These characteristics include the quality of resources that the TX UE can use in case of high / low priority, reliability, and latency, as well as the cast type (broadcast, groupcast, and unicast).

[0216] overview The embodiments of the present invention have been described in detail above, and each embodiment and aspect may be implemented individually, or two or more embodiments or aspects may be implemented in combination.

[0217] It should be noted that the above-described embodiments of various aspects of the present invention are described in an environment where communication takes place between a transmitter, such as a TX UE, and a receiver, such as a RX UE, in a V2X scenario. However, the present invention is not limited to such communication, rather the above-described principles may be applied to communication between any devices over a sidelink as well, such as D2D, V2V communication.

[0218] Thus, the embodiments described herein may be implemented in wireless communication systems, e.g. in vehicular communication systems, e.g. V2X, as in the context of cellular (e.g. 3G, 4G, 5G or future) or ad-hoc communication networks. The embodiments focus on optimal procedures for the base station (in mode 1) or the TX UE (in mode 2) to transmit control information regarding the resources used for (re)transmission of packets as well as the resources used for transmission of feedback.

[0219] Depending on the embodiment, the wireless communication system may include a terrestrial network, or a non-terrestrial network, or a network or segment of a network that uses airborne or satellite vehicles or a combination thereof as a receiver.

[0220] According to an embodiment, the User Equipment (UE) may be one or more of a mobile terminal, or a fixed terminal, or a cellular IoT-UE, or a vehicular UE, or a vehicle group leader (GL) UE, or an IoT, or a Narrowband IoT (NB-IoT) device, or a Non-Access Point WiFi (Non-AP STA), e.g. 802.11ax or 802.11be, or a ground-based vehicle, or an airborne vehicle, or a drone, or a mobile base station, or a roadside unit, or a building, or other item or device, such as a sensor or actuator, that is provided with network connectivity to enable communication using a wireless communication network, or other item or device, such as a sensor or actuator, that is provided with network connectivity to enable communication using a sidelink of a wireless communication network, or any sidelink capable network entity. The base station (BS) may be implemented as a mobile base station or a fixed base station, and may be any one or more of a macro cell base station, or a small cell base station, or a base station central unit, or a base station distribution unit, or a roadside unit, or a UE, or a group leader (GL), or a repeater, or a remote radio head, or an AMF, or an SMF, or a core network entity, or a mobile edge computing entity, or a network slice in a NR or 5G core context, or an 802.11ax or 802.11be WiFi AP STA, for example, or any transmit / receive point (TRP) that enables an item or device to communicate using a wireless communication network, where the item or device is provided with network connectivity for communicating using a wireless communication network.

[0221] Although some aspects of the described concepts have been described in the context of an apparatus, it will be apparent that these aspects also represent descriptions of corresponding methods, where a block or apparatus corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method step also represent descriptions of a corresponding block or item or feature of a corresponding apparatus.

[0222] Various elements and features of the invention may be implemented in hardware using analog and / or digital circuitry, in software, through the execution of instructions by one or more general-purpose or special-purpose processors, or as a combination of hardware and software. For example, embodiments of the invention may be implemented in the environment of a computer system or another processing system. FIG. 19 shows an example of a computer system 500. The units or modules, as well as the steps of the methods performed by these units, may be executed on one or more computer systems 500. The computer system 500 includes one or more processors 502, such as special-purpose or general-purpose digital signal processors. The processors 502 are connected to a communication infrastructure 504, such as a bus or a network. The computer system 500 includes a main memory 506, such as a random access memory (RAM), and a secondary memory 508, such as a hard disk drive and / or a removable storage drive. The secondary memory 508 may allow computer programs or other instructions to be loaded into the computer system 500. The computer system 500 may further include a communication interface 510, allowing software and data to be transferred between the computer system 500 and external devices. The communications may be from electronic, electromagnetic, optical, or other signals capable of being processed by the communications interface. Communications may use wire or cable, fiber optics, phone lines, cellular phone links, RF links, and other communications channels 512.

[0223] The terms "computer program medium" and "computer readable medium" are generally used to refer to tangible storage media, such as a hard disk installed in a removable unit or hard disk drive. These computer program products are means for providing software to the computer system 500. Computer programs, also called computer control logic, are stored in the main memory 506 and / or the secondary memory 508. The computer programs may also be received via the communication interface 510. The computer programs, when executed, enable the computer system 500 to perform the present invention. In particular, the computer programs, when executed, enable the processor 502 to perform the processes of the present invention, such as any of the methods described herein. Such computer programs may thus represent the controller of the computer system 500. When the present disclosure is implemented using software, the software may be stored in a computer program product and loaded into the computer system 500 using an interface, such as a removable storage medium, the communication interface 510.

[0224] The implementation in hardware or in software can be carried out using a digital storage medium, such as a floppy disk, DVD, Blu-ray, CD, ROM, PROM, EPROM, EEPROM or flash memory, having electronically readable control signals stored thereon and cooperating (or capable of cooperating) with a programmable computer system such that the respective method is executed. Hence, the digital storage medium can be computer readable.

[0225] Some embodiments of the present invention comprise a data carrier having electronically readable control signals capable of cooperating with a programmable computer system to cause one of the methods described herein to be performed.

[0226] Generally, embodiments of the present invention may be implemented as a computer program product with program code operable to perform one of the methods of the present invention when the computer program product runs on a computer. The program code may for example be stored on a machine readable carrier.

[0227] Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier. In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.

[0228] A further embodiment of the inventive method is therefore a data carrier (or digital storage medium or computer readable medium) comprising a computer program recorded thereon for performing one of the methods described herein. A further embodiment of the inventive method is therefore a data stream or a sequence of signals representing the computer program for performing one of the methods described herein. The data stream or the sequence of signals can for example be arranged to be transferred by a data communication connection, for example the Internet. A further embodiment comprises a processing means, for example a computer or a programmable logic device, configured to or adapted to perform one of the methods described herein. A further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.

[0229] In some embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functions of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. In general, the methods are preferably performed by any hardware apparatus.

[0230] The above described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to those skilled in the art. It is therefore intended that the present invention be limited only by the scope of the impending claims and not by the specific details expressed by the description and illustration of the embodiments herein.

[0231] List of acronyms and symbols TIFF0007680439000001.tif179132

Claims

1. 1. A transceiver for a wireless communication system, the wireless communication system including a plurality of user equipments (UEs) communicating with each other using a side link (SL), wherein: For transmission over the sidelink of a packet, the transceiver determines one or more transmission requirements for the transmission of the packet over the sidelink; and in response to the one or more transmission requirements determined, the transceiver transmits one or more control messages, the one or more control messages including parameters for a HARQ based retransmission using the sidelink and a blind retransmission using the sidelink. the transceiver is a transmitting UE (TX UE) that communicates with one or more receiving UEs (RX UEs) using the sidelink, and the one or more control messages are sidelink control information (SCI) messages that include sidelink control information (SCI); transceiver.

2. The one or more control messages: - a retransmission type indication, indicating whether the one or more retransmissions on the sidelink are a HARQ based retransmission or a blind retransmission; - Downlink Allocation Index (DAI); - a retransmission feedback resource location indication, indicating a resource location for transmitting feedback from the transmitting UE to a base station on a PUCCH; including one or more of:

2. The transceiver of claim 1.

3. The retransmission type indication is - explicit and includes an explicit parameter indicating whether the transmitted packet uses HARQ-based retransmission or blind retransmission, or - implicitly, by setting one or more predetermined parameters in said one or more control messages to a pre-defined or default value; 3. The transceiver of claim 2.

4. For an implicit retransmission type indication, The use of blind retransmissions includes: - using a non-numeric or default or pre-configured value of a PUCCH resource indication indicating resources used for the feedback on the PUCCH from the transmitting UE to the base station, or a PSSCH / PDCCH-HARQ timing indication between the one or more control messages and the feedback on the PUCCH, or - a resource location indication for said transmission and / or retransmission towards a set or resource pool of resources that does not include any resource of the PSFCH; and / or The use of HARQ based retransmissions includes: - resource location indication for said transmission and / or retransmission towards a set or resource pool of resources including resources of the PSFCH; Denoted by, and / or as indicated by the use of destination ID, priority information, or cast type; 4. The transceiver of claim 3.

5. The transceiver includes: - receiving an explicit parameter indicating that all permissible transmissions and / or retransmissions for said packet have been completed; 5. A transceiver according to any one of claims 2 to 4.

6. the transceiver, in response to the explicit parameter indicating that the transmission and / or retransmission for the packet is completed, stops allocating further resources for the packet, independent of feedback on a PSFCH.

6. The transceiver of claim 5.

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