Patent Description:
To meet the increasing demand for wireless data traffic after the commercialization of 4th generation (<NUM>) communication systems, efforts have been made to develop 5th generation (<NUM>) communication systems.

Accordingly, <NUM> communication systems have been lately commercialized. In order to achieve a high data transmission rate, <NUM> communication systems may be implemented in an ultrahigh frequency band, for example a millimeter wave (mmWave) band, or for example a <NUM> gigahertz (GHz) band. To reduce path loss of radio waves and increase a distance by which the radio waves propagate in the ultrahigh frequency band, a beamforming technique, a massive multiple-input and multiple-output (MIMO) technique, a full-dimensional MIMO (FD-MIMO) technique, an array antenna, an analog beam-forming technique, and a large-scale antenna technique have been or will be applied to <NUM> communication systems.

In addition, to improve networks of communication systems, techniques, such as evolved small cells, advanced small cells, a cloud radio access network (cloud RAN), an ultra-dense network, device-to-device communication (D2D), wireless backhaul, a moving network, cooperative communication, coordinated multi-points (CoMP), and received interference cancellation, have been or will be applied to <NUM> communication systems.

Furthermore, advanced coding modulation (ACM) techniques, such as hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) and advanced access techniques, such as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) have been or will be applied to <NUM> communication systems.

Moreover, unlike long-term evolution (LTE) V2X communication that supports only broadcast, a unicast and a groupcast are also supported in release-<NUM> (Rel-<NUM>) new-ratio (NR) V2X communication. Furthermore, a PSFCH has been newly defined to improve the reliability of the unicast and the groupcast. Accordingly, a transmitting terminal, for example a terminal configured to transmit signals and/or channels, may receive an acknowledgement/negative-acknowledgement (ACK/NACK) feedback from a receiving terminal, for example a terminal configured to receive signals and/or channels, through the PSFCH, and thus, hybrid automatic repeat request (HARQ) may be enabled.

For reference, a low peak-to-average power ratio (PAPR) sequence, which is based on a Zadoff-Chu sequence, may be applied to the PSFCH, and <NUM>-bit HARQ-ACK/NACK included in the PSFCH may have the above-described sequence format. Also, the PSFCH may be transmitted in units of <NUM> resource block (RB), and code division multiplexing (CDM) may be applied to the PSFCH so that a plurality of users (or terminals) may transmit the PSFCH through one RB.

However, because the transmitting terminal may simultaneously receive HARQ ACK/NACK from a plurality of receiving terminals in a groupcast mode, as the number of receiving terminals included in a group increases, the number of PSFCHs to be received by the transmitting terminal may increase. However, because a maximum number of PSFCHs that is transceivable by a terminal is not defined in a current 3rd generation partnership project (3GPP) standard, the number of PSFCHs received may exceed a PSFCH receiving capability of the transmitting terminal depending on circumstances. Furthermore, because the transmitting terminal has to determine whether all PSFCHs received from the plurality of receiving terminals are ACK or NACK, an operation of determining whether the PSFCHs are ACK or NACK may increase the work load on the transmitting terminal.

<CIT> discloses a method for measuring signal reception power of a vehicle to everything (V2X) terminal in a wireless communication system and provides a method which receives information on at least one of whether a transmission diversity mode coexists on V2X resource pool set by the terminal, the number of antenna ports used by the transmission diversity mode of another terminal for which the terminal intends to measure the signal reception power, and the transmission diversity technique type of the other terminal, and detects a specific terminal performing a transmission diversity-based V2X transmission operation based on the information, and measures the physical sidelink shared channel reference signal received power (PSSCH RSRP) for the specific terminal.

Provided are an apparatus and method for efficiently transceiving a physical sidelink feedback channel (PSFCH) to perform vehicle-to-everything (V2X) communication in a wireless communication system.

The above and other aspects, features, and advantages of certain embodiments of the present disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings in which:.

Embodiments may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. The embodiments may be interchangeable with each other. Rather, these embodiments are provided so that this disclosure is thorough and complete and fully conveys the scope to those skilled in the art. Even when content described in a specific embodiment is not described in other embodiments, the content may be understood as being related to other embodiments unless described otherwise or the content contradicts the specific embodiment in the other embodiments. Like numbers generally refer to like elements throughout the specification.

The terms used herein are to just describe specific embodiments and not intended to limit the scope of other embodiments. The expression of a singular form may include the expression of a plural form unless otherwise indicating clearly in context.

Unless otherwise defined, all terms (including technical and scientific terms) used herein are to be interpreted as is customary in the art to which this disclosure belongs. It will be further understood that terms in common usage should also be interpreted as is customary in the relevant art and not in an idealized or overly formal sense unless explicitly so defined herein.

In addition, embodiments will be described in detail by focusing new-radio (NR) systems and long-term evolution (LTE)/ LTE-Advanced (LTE-A) systems. However, at the judgement of one skilled in the art, the embodiments may be applied not only to other communication systems having similar technical backgrounds but also to other communication systems using licensed and unlicensed bands with slight modifications within the scope of the disclosure.

Before the following detailed description, the definitions of several words and phrases used throughout the specification will be described. An expression "being connected (combined/accessed) to" and derivatives thereof may refer to any direct or indirect communication between at least two components regardless of whether the at least two components are in physical contact with each other. Terms "transmitting," "receiving," and "communicating" and derivatives thereof may include both direct and indirect communications. Terms "comprising" and "including" and derivatives thereof may refer to inclusion without limitation. A term "or" may be an inclusive word meaning 'and/or. ' An expression "being related to" and derivatives thereof may refer to including, being included in, being interconnected with, contain, being contained in, being connected to/with, being combined to/with, communicating with, cooperating with, interposing, putting in parallel, approximating to, being bound by, having, being characterized by, having a relationship with, and the like. A term "controller" refers to a device, a system, or a portion thereof, which controls at least one operation. The controller may be implemented in hardware or a combination of hardware and software and/or firmware. Functions related to any specific controller may be centralized or distributed locally or remotely. When an expression "at least one of" precedes a list of items, any and all combinations of one or more of the listed items may be used or only one of the listed items may be needed. For example, an expression "at least one of A, B, and C" may include any one of A, B, C, both A and B, both A and C, both B and C, and combinations of A, B, and C.

Various functions described below may be implemented or supported by one or more computer programs, each of which may be composed of computer-readable program code and executed on a computer readable medium. As used herein, terms "application" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, related data, or portions thereof, which are suitable for the implementation of suitable computer-readable program code. The term "computer-readable program code" includes all types of computer code including source code, object code, and execution code. The term "computer-readable medium" includes all types of media, such as read-only memory (ROM), random access memory (RAM), hard disc drive (HDD), compact disc (CD), digital video disc (DVD), or any other type of memory, which may be accessed by a computer. A "non-transitory" computer-readable medium excludes wired, wireless, optical, or other communication links that transmit transitory electrical or other signals. The non-transitory computer-readable medium includes a medium in which data may be stored permanently and a medium, for example a rewritable optical disc or an erasable memory device, in which data may be stored and overwritten later.

In various embodiments described below, a hardware access method will be explained as an example. However, the various embodiments include a technology using both hardware and software, and thus, the various embodiments do not exclude a software-based access method.

In the following description, a term referring to control information, a term referring to an entry, a term referring to network entities, a term referring to messages, and a term referring to a component of an apparatus will be provided as examples for brevity. Accordingly, embodiments are not limited by terms described below, and other terms having equivalent technical meanings may be used instead.

<FIG> is a diagram for explaining a unicast, a groupcast, and a physical sidelink feedback channel (PSFCH) transmission process, which are performed between terminals through a sidelink, according to an example embodiment.

<FIG> illustrates a plurality of terminals, for example first terminal <NUM>, second terminal <NUM>, third terminal <NUM>, fourth terminal <NUM>, fifth terminal <NUM>, sixth terminal <NUM>, seventh terminal <NUM>, and eighth terminal <NUM>, configured to perform vehicle-to-everything (V2X) communication according to an embodiment.

To begin with, it can be seen that a communication scheme between the first terminal <NUM> and second terminal <NUM> is one-to-one communication, that is, unicast communication performed through a sidelink.

Although <FIG> illustrates an example in which a signal is transmitted from the first terminal <NUM> to the second terminal <NUM>, the signal may be transmitted in an opposite direction. That is, the signal may be transmitted from the second terminal <NUM> to the first terminal <NUM>.

In addition, an operation of exchanging signals between the first and second terminals <NUM> and <NUM> through a unicast may include performing a scrambling process, a control information mapping process, a data transmission process, and a unique identification (ID) value verification process by using resources or values known between the first and second terminals <NUM> and <NUM>. Also, the first and second terminals <NUM> and <NUM> may be mobile terminals, such as vehicles.

Thereafter, it can be seen that a communication scheme between the third to fifth terminals <NUM>, <NUM>, and <NUM> is groupcast communication in which the third terminal <NUM> transmits common data to other terminals, for example the fourth and fifth terminals <NUM> and <NUM>, in a group through a sidelink.

During the groupcast communication, other terminals, for example the second and seventh terminals <NUM> and <NUM>, that are not included in the group may not receive signals transmitted by the third terminal <NUM> for a groupcast.

For reference, a terminal configured to transmit signals for the groupcast may not be the third terminal <NUM> but another terminal, for example the fourth terminal <NUM> or the fifth terminal <NUM>, in the group. Also, the allocation of resources to transmit signals may be determined by a base station or a terminal serving as a leader in the group or may be selected by the terminal configured to transmit the signals. In addition, the third to fifth terminals <NUM>, <NUM>, and <NUM> may be mobile terminals, such as vehicles.

Finally, communication among the sixth to eighth terminals <NUM>, <NUM>, and <NUM> will now be examined. A communication scheme may include communication in which the seventh and eighth terminals <NUM> and <NUM> receive common data from the sixth terminal <NUM> in groupcast communication and transmit feedback on information related to a success or failure of reception of the common data to the sixth terminal <NUM>. Although not shown, feedback on information related to a success or failure of reception of data may also be transmitted between terminals, for example the first and second terminals <NUM> and <NUM>, which are in unicast communication.

For reference, the information related to the success or failure of reception of the data may be Hybrid Automatic Repeat reQuest (HARQ)-acknowledgement/negative-acknowledgement (ACK/NACK) information, which may be included in a PSFCH. Also, the sixth to eighth terminals <NUM>, <NUM>, and <NUM> may be mobile terminals, such as vehicles.

As described above, various communication schemes may be applied between the plurality of terminals, for example the first to eighth terminals <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> configured to perform V2X communication according to an example embodiment. Hereinafter, <FIG> will be described based on V2X communication schemes.

<FIG> is a diagram for explaining a process of transmitting signaling between a terminal and a base station and a process of transceiving channels between terminals, according to example embodiments.

Referring to <FIG>, a wireless communication system <NUM> according to an example embodiment may include a base station <NUM> and a plurality of terminals, for example terminals <NUM> and <NUM>.

For reference, although <FIG> illustrates an example in which the wireless communication system <NUM> includes only two terminals <NUM> and <NUM> and one base station <NUM> for brevity, the disclosure is not limited thereto. That is, the wireless communication system <NUM> may include more or fewer terminals and base stations.

In addition, each of the terminals <NUM> and <NUM> shown in <FIG> may be all capable of V2X communication, for example unicast, groupcast, and PSFCH transmission, described with reference to <FIG>. Thus, although unicast communication between the two terminals <NUM> and <NUM> is illustrated in <FIG> may be interpreted as the illustration of groupcast communication between some terminals of a group.

The wireless communication system <NUM> may be referred to as radio access technology (RAT). For example, the wireless communication system <NUM> may be a wireless communication system using a cellular network, such as an NR communication system, an LTE communication system, an LTE-advanced (LTE-A) communication system, a code division multiple access (CDMA) communication system, and a global system for mobile communications (GSM) communication system. In embodiments, the wireless communication system <NUM> may be a wireless local area network (WLAN) communication system, or another arbitrary wireless communication system.

A wireless communication network used in the wireless communication system <NUM> may share available network resources and support the communication of a plurality of wireless communication devices including the terminals <NUM> and <NUM>.

For example, in the wireless communication network, information may be transmitted using various multiple access methods, such as CDMA, frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), OFDM-FDMA, OFDM-TDMA, and OFDM-CDMA.

In embodiments, the wireless communication system <NUM> may be an NR communication system. However, example embodiments are not limited thereto and may also be applied to previous-generation and next-generation wireless communication systems.

Moreover, the base station <NUM> may refer to a fixed station configured to communicate with the terminals <NUM> and <NUM> and/or another base station. The base station <NUM> may communicate with the terminals <NUM> and <NUM> and/or another base station and exchange data and control information with the terminals <NUM> and <NUM> and/or another base station.

For example, the base station <NUM> may be referred to as Node B, evolved-Node B (eNB), next-generation Node B (gNB), a sector, a site, a base transceiver system (BTS), an access point (AP), a relay node, a remote radio head (RRH), or a radio unit (RU).

In the present embodiment, the base station <NUM> may be interpreted as a partial area or function covered by a base station controller (BSC) of CDMA, Node B of wideband CDMA (WCDMA), eNB of LTE, gNB of NR, or a sector (site). The terminals <NUM> and <NUM> may be fixed devices as user devices or mobile devices as vehicles and may refer to any devices capable of communicating with the base station <NUM> and transmitting and receiving data and/or control information to and from the base station <NUM>.

For example, the terminals <NUM> and <NUM> may be referred to as wireless stations (STA), mobile stations (MS), mobile terminals (MT), user terminals (UT), user equipment (UE), subscriber stations (SS), wireless devices, handheld devices, or vehicles.

Moreover, the base station <NUM> may be connected to the terminals <NUM> and <NUM> through wireless channels and provide various communication services to the terminals <NUM> and <NUM> through the connected wireless channels. Also, all user traffic of the base station <NUM> may be serviced through a shared channel. In addition, the base station <NUM> may schedule the terminals <NUM> and <NUM> by collecting status information, such as PSFCH capabilities, buffer states, available transmission power states, and channel states of the terminals <NUM> and <NUM>.

Furthermore, the wireless communication system <NUM> may support a beam-forming technique using an orthogonal frequency division multiplexing (OFDM) scheme. In addition, the wireless communication system <NUM> may support an adaptive modulation & coding (AMC) scheme, which determines a modulation scheme and a channel coding rate based on channel states of the terminals <NUM> and <NUM>.

For reference, the wireless communication system <NUM> may transmit and receive signals using a wide frequency band including not only a frequency band of less than <NUM> but also a frequency band of <NUM> or more.

For example, the wireless communication system <NUM> may increase a data transmission rate by using a millimeter wave band, such as a <NUM> band or a <NUM> band.

A signal attenuation per distance may be relatively large in the millimeter wave band. Thus, the wireless communication system <NUM> may support a transceiving operation based on a directional beam to ensure coverage. Furthermore, the wireless communication system <NUM> may perform a beam sweeping operation to enable the transceiving operation based on the directional beam.

Here, the beam sweeping operation may indicate that the terminals <NUM> and <NUM> and the base station <NUM> sequentially or randomly sweep directional beams having a predetermined pattern to determine a transmission beam and a receiving beam of which orientation directions are aligned with each other. That is, patterns of the transmission beam and the receiving beam of which the orientation directions are aligned with each other may be determined as a pair of beam patterns. Also, a beam pattern may refer to a shape of a beam, which is determined based on a width of the beam and an orientation direction of the beam.

Because the terminals <NUM> and <NUM> and the base station <NUM> of the wireless communication system <NUM> may be configured and operate as described above, communication between the terminals <NUM> and <NUM> or between the terminals <NUM> and <NUM> and the base station <NUM> will now be described in further detail.

The terminals <NUM> and <NUM> may transmit or receive signals SIG1, SIG2, SIG4, and SIG4 to and from the base station <NUM> through an uplink or a downlink and access a network of the wireless communication system <NUM>. A link between the terminals <NUM> and <NUM> and the base station <NUM>, for example a data transceiving interface, may be referred to as a Uu link. Furthermore, to exchange various pieces of setting information required for a signal transceiving operation between the terminals <NUM> and <NUM> and the base station <NUM>, radio resource control (RRC) connection may be made between the terminal <NUM> or <NUM> and the base station <NUM>. The RRC connection may be referred to as Uu-RRC.

Specifically, for example, the terminals <NUM> and <NUM> may transmit the signals SIG2 and SIG4 for a maximum number of PSFCHs, which may be transceived during one time transmission interval (TTI), for example a slot, to the base station <NUM>. In embodiments, the maximum number of PSFCHs which may be transceived during one TTI may be referred to as a maximum PSFCH transceiving capability, or a max PSFCH transceiving capability. Also, information about the max PSFCH transceiving capability may correspond to RRC information, which may be one of user equipment (UE) capability information elements. Accordingly, the terminals <NUM> and <NUM> may transmit the signals SIG2 and SIG4 for the max PSFCH transceiving capability to the base station <NUM> due to RRC signaling. Thus, the information about the max PSFCH transceiving capability may be included in a physical uplink shared channel (PUSCH). The information about the max PSFCH transceiving capability may be included in a physical uplink control channel (PUCCH) or a physical random access channel (PRACH) in addition to the PUSCH, but an example embodiment pertains an example in which the information is included in the PUSCH.

For reference, in the present embodiment, the contents disclosed in Table <NUM> may be newly introduced and defined in connection with the max PSFCH transceiving capability of a terminal. Thus, the terminals <NUM> and <NUM> may signal for the max PSFCH transceiving capability to the base station <NUM> based on items described in Table <NUM>.

For example, 'UE capability signaling' of item (<NUM>) of Table <NUM> may be expressed as shown in Table <NUM> below.

Furthermore, the contents disclosed in Table <NUM> may be arranged as in Table <NUM>-<NUM> and Table <NUM>-<NUM> below.

For reference, Table <NUM>-<NUM> and Table <NUM>-<NUM> are tables into which one continuous table is divided on account of limited space.

As described above, in an example embodiment, the terminal <NUM> or <NUM> may signal for the max PSFCH transceiving capability to the base station <NUM>, an example of which will be described in further detail with reference to <FIG>. Moreover, the base station <NUM> may perform RRC signaling, for example signals SIG1 and SIG3, to the terminals <NUM> and <NUM> based on the signaling from the terminals <NUM> and <NUM> and perform a scheduling operation for transmitting and receiving signals, for example PSSCH, PSCCH, and PSFCH, between the terminals <NUM> and <NUM> or perform groupcast-related setting operations of, for example, selecting a leader in a group and setting a size of a zone for a groupcast.

For reference, the terminals <NUM> and <NUM> may receive scheduling information for sidelink communication, based on the RRC signaling, for example signals SIG1 and SIG3, from the base station <NUM> or information, for example downlink control information (DCI), of a physical downlink control channel (PDCCH).

In addition, the terminals <NUM> and <NUM> may transmit and receive signals, for example channel CH1, channel CH2, and channel CH3, to and from each other through a sidelink. The sidelink, for example a data transceiving interface, between the terminals <NUM> and <NUM> may be referred to as a PC5 link. Furthermore, to exchange various pieces of setting information required to transceive the signals between the terminals <NUM> and <NUM>, RRC connection may be made between the terminals <NUM> and <NUM>. The RRC connection may be referred to as PC5-RRC.

Herein, the channels transceived through the sidelink may include, for example, a sidelink control channel, for example a physical sidelink control channel (PSCCH), a sidelink shared channel or data channel, for example a physical sidelink shared channel (PSSCH), a sidelink broadcast channel, for example a physical sidelink broadcast channel (PSBCH) broadcasted with a synchronization signal, and a feedback transmission channel, for example a physical sidelink feedback channel (PSFCH).

In embodiments, the terminal <NUM> configured to perform a data transmission operation in the sidelink may be referred to as a transmitting terminal, and the terminal <NUM> configured to perform a data receiving operation in the sidelink may be referred to as a receiving terminal. Both the transmitting terminal and the receiving terminal may respectively perform the data transmission operation and the data receiving operation in the sidelink.

The transmitting terminal <NUM> may generate sidelink scheduling information, for example sidelink control information (SCI), based on scheduling information provided by the base station <NUM>. Also, the transmitting terminal <NUM> may transmit a PSCCH CH1 including the generated sidelink scheduling information to the receiving terminal <NUM>.

Here, the sidelink scheduling information may be transmitted as single SCI to the receiving terminal <NUM> or may be divided into two pieces of SCI and transmitted to the receiving terminal <NUM>. For reference, a method in which the sidelink scheduling information is divided into two pieces of SCI and transmitted to the receiving terminal <NUM> may be referred to as <NUM>-stage SCI, or a <NUM>-stage PSCCH.

The transmitting terminal <NUM> may transmit a PSSCH CH2, which is a data channel, to the receiving terminal <NUM>, based on the sidelink scheduling information. Also, the receiving terminal <NUM> may transmit feedback on a PSFCH CH3, which includes information, for example HARQ-ACK/NACK, related to a success or failure of the reception of the PSSCH CH2 transmitted by the transmitting terminal <NUM>, to the transmitting terminal <NUM>. Thus, the transmitting terminal <NUM> may determine whether the PSFCH CH3 received from the receiving terminal <NUM> includes HARQ ACK or NACK and determine whether the PSSCH CH2 is to be retransmitted, based on the determination result.

As described above, various signals or channels may be transmitted and received between the terminals <NUM> and <NUM> and the base station <NUM> as will be described below in further detail.

The wireless communication system <NUM> according to an example embodiment has characteristics and configurations as described above. Thus, a structure of a time-frequency range applied to a sidelink of an NR communication system according to an example embodiment will now be described with reference to <FIG>.

For reference, the structure of the time-frequency range shown in <FIG> may be an example of a time-frequency range applicable to the present embodiment, and thus, the disclosure is not limited thereto. However, for brevity, the structure of the time-frequency range shown in <FIG> will be described as an example.

To begin with, referring to <FIG>, the abscissa denotes a time area, and the ordinate denotes a frequency range. A minimum transmission unit in the time domain may be an OFDM symbol, and Nsymb OFDM symbols may form one slot. A length of a subframe may be <NUM>, and a length of a radio frame may be <NUM>. A minimum transmission unit in the frequency range may be a subcarrier, and a system transmission bandwidth may include a total of NBW subcarriers.

In the time-frequency range, a basic unit of a resource may be a resource element (RE), which may be expressed by an OFDM symbol index and a subcarrier index. A resource block (RB) or a physical resource block (PRB) may be defined by Nsymb consecutive OFDM symbols in the time domain and NRB consecutive subcarriers in the frequency domain. Accordingly, one RB may include Nsymb x NRB REs.

For reference, a minimum transmission unit of data may be typically an RB unit. In the NR communication system, typically, Nsymb may be at least one, NRB may be equal to <NUM>, and NBW and NRB may be proportional to the system transmission bandwidth. Also, a data rate may increase in proportion to the number of RBs, which is scheduled for a terminal.

In addition, a channel bandwidth may indicate an RF bandwidth corresponding to the system transmission bandwidth. For example, in an NR communication system having a channel bandwidth of <NUM> at a subcarrier width of <NUM>, a transmission bandwidth may include <NUM> RBs.

Referring to <FIG> and <FIG> based on the above description, a subchannel and a resource pool defined to improve resource use efficiency in release-<NUM> (Rel-<NUM>) NR V2X communication are illustrated. For reference, a basic frame structure, for example a structure of a time-frequency domain, of NR V2X communication and a <NUM>-stage PSCCH are illustrated in <FIG>. Also, a resource pool is illustrated in <FIG>.

Specifically, in the NR V2X communication, one slot may include at least one resource pool, each of which may include a plurality of subchannels. Here, a size of the subchannel may be, for example, any one of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> RBs. However, the size of the subchannel may be any one of <NUM>, <NUM>, and <NUM> RBs according to circumstances. As an example, <FIG> illustrates an example which includes subchannel #<NUM> and subchannel #<NUM>, and each of subchannel #<NUM> and subchannel #<NUM> includes <NUM> RBs, illustrated as RB #<NUM> of subchannel #<NUM> through RB #<NUM> of subchannel #<NUM>, and RB #<NUM> of subchannel #<NUM> through RB #<NUM> of subchannel #<NUM>.

In addition, a <NUM>-th symbol (symbol <NUM>) of the slot may be a symbol for automatic gain control (AGC) training.

Furthermore, a PSFCH for determining whether a PSSCH is normally received may be allocated and transmitted in a twelfth symbol (symbol <NUM>) of the slot. Transmission timing may be in two or three slots after a slot in which the PSSCH is transmitted. For example, when a PSSCH is transmitted in a slot A, a PSFCH corresponding to the PSSCH may be transmitted feedback in a slot A+<NUM> or a slot A+<NUM>.

For reference, a PSFCH may include <NUM> PRB (or <NUM> RB) and be transmitted for each subchannel. Also, a transceiving period of each PSFCH may be set, and a minimum value of the transceiving period may be defined as <NUM>, for example <NUM> slot unit. Since a plurality of PSFCHs may use the same resource, up to six cyclic shifts may be applied to different PSFCHs transmitted to the same RB. Accordingly, up to ( <MAT> subchannel) ≈ <NUM> PSFCHs may be transmitted during each slot.

AGC for receiving a PSFCH may be allocated in a symbol (for example, symbol <NUM>) immediately preceding the PSFCH. Because a transmission subject, for example a transmitting terminal, of the <NUM>-th to ninth symbols (symbols <NUM> to <NUM>) is different from a transmitting terminal, for example a receiving terminal, of the eleventh and twelfth symbols (symbols <NUM> and <NUM>), the AGC for the PSFCH may be separately needed.

In addition, a guard symbol may be allocated to the tenth and thirteenth symbols (symbols <NUM> and <NUM>) to ensure a guard time for timing advance. Because the transmission subject of the <NUM>-th to ninth symbols (symbols <NUM> to <NUM>) is different from the transmitting terminal of the eleventh and twelfth symbols (symbols <NUM> and <NUM>), symbol timings may be misaligned by a receiver, and thus, the guard symbol may be needed.

Demodulation reference signals (DMRSs), PSCCHs, and PSSCHs may be allocated to the first to ninth symbols (symbols <NUM> to <NUM>) other than the channels and symbols described above. Furthermore, PSFCHs, AGC, and guard symbols may be allocated to the first to ninth symbols (symbols <NUM> to <NUM>). However, for brevity, an example embodiment pertains to an example in which PSFCHs, AGC, and guard symbols are allocated to the tenth to thirteenth symbols.

For reference, in the NR V2X communication, because the PSCCH is transmitted by two stages, a 1st PSCCH may be originally allocated to a PSCCH scheduling range, and a 2nd PSCCH may be allocated to a PSSCH range.

More specifically, the 1st PSCCH may be present from a lowest RB (e.g., RB #<NUM> of subchannel #<NUM>) of a subchannel and include 1st SCI. Also, the 1st SCI may include allocation information, for example frequency domain resource allocation (FDRA) and time domain resource allocation (TDRA), of the PSSCH and allocation information of the 2nd PSCCH. The 2nd PSCCH may include 2nd SCI and be first allocated to a lowest RE, for example SC #<NUM>, where SC refers to a subcarrier, excluding an RE for a DMRS in a first DMRS symbol, for example a DMRS of symbol <NUM>. In addition, the 2nd SCI may include information required to decode the PSSCH.

As described above, a time-frequency range applied to the sidelink of the NR communication system may be configured according to the present embodiment. Hereinafter, a configuration of a radio-frequency (RF) transceiver of a terminal or a base station, according to an example embodiment, will be described with reference to <FIG> and <FIG>.

<FIG> is a block diagram of RF transceiver components included in a terminal or a base station, according to an example embodiment. <FIG> is a simplified block diagram of RF transceiver components of <FIG>, according to an embodiment.

For reference, the RF transceiver components of <FIG> and <FIG> may be included in the terminal <NUM> or <NUM> of <FIG> or the base station <NUM>. Also, the RF transceiver components of <FIG> and <FIG> may include both components in a transmitting path and components in a receiving path.

Hereinafter, for brevity, an example in which the RF transceiver components illustrated in <FIG> and <FIG> are included in the terminal <NUM> of <FIG> will be described. Also, a baseband circuit <NUM> of <FIG> will be described centering on the components in the receiving path.

To begin with, referring to <FIG>, the terminal such as terminal <NUM> may include an antenna <NUM>, a front-end module (FEM) <NUM>, an RF integrated circuit (RFIC) <NUM>, and the baseband circuit <NUM>.

The antenna <NUM> may be connected to the FEM <NUM> and transmit a signal provided by the FEM <NUM> to another wireless communication device, for example a terminal or a base station, or provide a signal received from another wireless communication device to the FEM <NUM>. Also, the FEM <NUM> may be connected to the antenna <NUM> and separate a transmission frequency from a receiving frequency. That is, the FEM <NUM> may separate a signal provided by the RFIC <NUM> for each frequency band and provide the separated signal to the antenna <NUM> corresponding thereto. In addition, the FEM <NUM> may provide a signal provided by the antenna <NUM> to the RFIC <NUM>.

As described above, the antenna <NUM> may transmit the signal, of which the frequency is separated, to the outside, for example the outside of the terminal such as terminal <NUM>, or provide an externally received signal to the FEM <NUM>.

For reference, the antenna <NUM> may include, for example, an array antenna, without being limited thereto. Also, the antenna <NUM> may be provided in singular or plural. Thus, in some embodiments, terminal <NUM> may support a phased array and multi-input and multiple-output (MIMO) using a plurality of antennas. However, one antenna <NUM> is illustrated in <FIG> for brevity.

The FEM <NUM> may include an antenna tuner. The antenna tuner may be connected to the antenna <NUM> and adjust an impedance of the antenna <NUM>.

The RFIC <NUM> may perform an up-conversion on a baseband signal received from the baseband circuit <NUM> and generate an RF signal. Also, the RFIC <NUM> may perform a down-conversion on an RF signal received from the FEM <NUM> and generate a baseband signal.

Specifically, the RFIC <NUM> may include a transmit circuit <NUM> for an up-conversion operation, a receive circuit <NUM> for a down-conversion operation, and a local oscillator <NUM>.

For reference, the transmit circuit <NUM> may include a first analog baseband filter, a first mixer, and a power amplifier. Also, the receive circuit <NUM> may include a second analog baseband filter, a second mixer, and a low-noise amplifier.

Here, the first analog baseband filter may filter the baseband signal received from the baseband circuit <NUM> and provide the filtered baseband signal to the first mixer. Also, the first mixer may perform an up-conversion of converting a frequency of the baseband signal from a baseband to a high-frequency band according to a frequency of a signal provided by the local oscillator <NUM>. Due to the up-conversion, the baseband signal may be provided as an RF signal to the power amplifier, and the power amplifier may amply power of the RF signal and provide the RF signal, of which power is amplified, to the FEM <NUM>.

The low-noise amplifier may amplify the RF signal provided by the FEM <NUM> and provide the amplified RF signal to the second mixer. The second mixer may perform a down-conversion of converting a frequency of the RF signal from a high-frequency band to a baseband according to the frequency of the signal provided by the local oscillator <NUM>. Due to the down-conversion, the RF signal may be provided as a baseband signal to the second analog baseband filter, and the second analog baseband filter may filter the baseband signal and provide the filtered baseband signal to the baseband circuit <NUM>.

Moreover, the baseband circuit <NUM> may receive a baseband signal from the RFIC <NUM> and process the baseband signal or generate the baseband signal and provide the baseband signal to the RFIC <NUM>.

In addition, the baseband circuit <NUM> may include a controller <NUM>, a storage <NUM>, and a signal processing unit <NUM>.

Specifically, the controller <NUM> may control not only the overall operations of the baseband circuit <NUM> but also the overall operations of the RFIC <NUM>. Also, the controller <NUM> may write data to the storage <NUM> or read data from the storage <NUM>. To this end, the controller <NUM> may include at least one processor, at least one microprocessor, or at least one microcontroller or be a portion of a processor. More specifically, the controller <NUM> may include, for example, a central processing unit (CPU) and a digital signal processor (DSP).

The storage <NUM> may store basic programs, application programs, and data, for example setting information, for operations of the terminal <NUM>. For example, the storage <NUM> may store instructions and/or data associated with the controller <NUM>, the signal processing unit <NUM>, or the RFIC <NUM>.

Furthermore, the storage <NUM> may include various storage media. That is, the storage <NUM> may include a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. For example, the storage <NUM> may include random access memory (RAM), for example dynamic RAM (DRAM), phase-change RAM (PRAM), magnetic RAM (MRAM), and static RAM (SRAM), and flash memory, such as NAND flash memory, NOR flash memory, and OneNAND flash memory.

In addition, the storage <NUM> may store various processor-executable instructions. The processor-executable instructions may be executed by the controller <NUM>.

The signal processing unit <NUM> may process the baseband signal received from the RFIC <NUM>.

Specifically, the signal processing unit <NUM> may include a demodulator <NUM>, a RxFilter & cell searcher <NUM>, and other components <NUM>.

To begin with, the demodulator <NUM> may include a channel estimator, a data deallocation unit, an interference whitener, a symbol detector, a channel state information (CSI) generator, a mobility measurement unit, an automatic gain control unit, an automatic frequency control unit, a symbol timing recovery unit, a delay spread estimation unit, and a time correlator and perform functions of each of components described above.

Herein, the mobility measurement unit may be a unit configured to measure signal quality of serving cells and/or neighbor cells to support mobility. The mobility measurement unit may measure a received signal strength indicator (RSSI), a reference signal received power (RSRP), a reference signal received quality (RSRQ), a reference signal (RS)-signal-to-interference-plus(&)-noise ratio (SINR) of cells.

For reference, although not shown, the demodulator <NUM> may include a plurality of sub-demodulators configured to independently or jointly perform the above-described operations on signals, which are respectively de-spread in a 2nd generation (<NUM>) communication system, a 3rd generation (<NUM>) communication system, a 4th generation (<NUM>) communication system, and a 5th generation (<NUM>) communication system, or signals of respective frequency bands.

Thereafter, the RxFilter & cell searcher <NUM> may include a RxFilter, a cell searcher, a fast Fourier transform (FFT) unit, a time duplex-automatic gain control (TD-AGC) unit, and a time duplex-automatic frequency control (TD-AFC) unit.

Herein, the RxFilter, which may also be referred to as an receiver (Rx) front end, may perform sampling, interference cancellation, and amplification on the baseband signal received from the RFIC <NUM>. Also, the cell detector may include a primary synchronization signal (PSS) detector and a secondary synchronization signal (SSS) detector and measure magnitudes and quality of signals from adjacent cells.

Moreover, the other components <NUM> may include a symbol processor, a channel decoder, and an uplink processor.

Herein, the symbol processor may perform channel-deinterleaving, demultiplexing, and rate-matching to decode demodulated signals for each channel. Also, the channel decoder may decode the demodulated signals in units of code blocks.

For reference, the symbol processor and the channel decoder may include a hybrid automatic repeat request (HARQ) processing unit, a turbo decoder, a cyclic redundancy check (CRC) checker, a Viterbi decoder, and a turbo encoder.

The uplink processor, which is a processor configured to generate a transmission baseband signal, may include a signal generator, a signal allocator, an inverse fast Fourier transform (IFFT) unit, a discrete Fourier transform (DFT) unit, and a transmitter (Tx) front end.

Herein, the signal generator may generate a PUSCH, a PUCCH, and a PRACH. Also, the Tx Front End may perform operations, such as an interference cancellation and a digital mixing, on the transmission baseband signal.

For reference, the other components <NUM> may further include a sidelink processor. The sidelink processor may generate a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), and a physical sidelink feedback channel (PSFCH). In another case, the sidelink processor may not be separately provided but integrated with the uplink processor into one processor. However, for brevity, an example embodiment pertains an example in which the sidelink processor is provided separately from the uplink processor.

The signal processing unit <NUM> may have configurations and characteristics described above. However, respective configurations or functions of the demodulator <NUM>, the RxFilter & cell searcher <NUM>, and the other components <NUM> in the signal processing unit <NUM> may be changed. For example, the channel estimator in the demodulator <NUM> may be included in the RxFilter & cell searcher <NUM> or the other components <NUM>, and the FFT unit in the RxFilter & cell searcher <NUM> may be included in the demodulator <NUM> or the other components <NUM>. Also, the channel decoder in the other components <NUM> may be included in the demodulator <NUM> or the RxFilter & cell searcher <NUM>. However, for brevity, an example embodiment pertains an example in which respective configurations or functions of the demodulator <NUM>, the RxFilter & cell searcher <NUM>, and the other components <NUM> in the signal processing unit <NUM> are implemented as described above.

As described above, <FIG> illustrates a case in which the baseband circuit <NUM> includes the controller <NUM>, the storage <NUM>, and the signal processing unit <NUM>.

However, at least two of the controller <NUM>, the storage <NUM>, and the signal processing unit <NUM> may be integrated into one component in the baseband circuit <NUM>. Also, the baseband circuit <NUM> may further include additional components other than the above-described components or may not include some components. Furthermore, the signal processing unit <NUM> may further include additional components other than the above-described components or may not include some components.

However, for brevity, an example embodiment pertains an example in which the baseband circuit <NUM> includes the components described above.

Furthermore, in some embodiments, the controller <NUM>, the storage <NUM>, and the signal processing unit <NUM> may be included in one device. In other embodiments, the controller <NUM>, the storage <NUM>, and the signal processing unit <NUM> may be distributed and included in respectively different devices , for example in a distributed architecture.

The RF transceiver components of <FIG>, which has the above-described configuration may be included in, for example, one or more of the terminal <NUM> or <NUM> or the base station <NUM> of <FIG>.

The RFIC <NUM> and the baseband circuit <NUM> may include components, which are well known to one of ordinary skill as shown in <FIG>. Also, the components may be executed in a known manner by using hardware, firmware, a software logic or a combination thereof.

However, <FIG> illustrates only an example of the RF transceiver components, and embodiments are not limited thereto. That is, various changes, for example addition or deletion of components, may be made in <FIG>.

<FIG> illustrates an example in which a configuration of the RF transceiver components of <FIG> is partially changed, for example simplified.

Specifically, the terminal <NUM> may include a processor <NUM>, a transceiver <NUM>, a memory <NUM>, and an antenna <NUM>.

The processor <NUM> may control the overall operations of the transceiver <NUM> and write or read data to or from the memory <NUM>. That is, the processor <NUM> may be, for example, a component including functions of the controller <NUM> of <FIG>.

The transceiver <NUM> may transmit and receive wireless signals and be controlled by the processor <NUM>. That is, the transceiver <NUM> may be, for example, a component including functions of the FEM <NUM>, the RFIC <NUM>, and the signal processing unit <NUM> of <FIG>.

The memory <NUM> may include basic programs, application programs, and data, for example setting information, for operations of the terminal <NUM>. Thus, the memory <NUM> may store instructions and/or data associated with the processor <NUM> and the transceiver <NUM>. That is, the memory <NUM> may be, for example, a component including functions of the storage <NUM> of <FIG>.

The antenna <NUM> may be connected to the transceiver <NUM> and transmit a signal provided by the transceiver <NUM> to another wireless communication device, for example a terminal or a base station, or provide a signal received from another wireless communication device to the transceiver <NUM>. That is, the antenna <NUM> may be, for example, a component including functions of the antenna <NUM> of <FIG>.

Because the terminal <NUM> or <NUM> or the base station <NUM> has characteristics and configurations described above in an example embodiment, an example of a process of signaling between the terminal <NUM> or <NUM> and the base station <NUM> to enable V2X communication will now be described in detail with reference to <FIG>.

<FIG> is a flowchart of a signaling process performed between the terminal <NUM> or <NUM> and the base station <NUM> of <FIG>, according to an embodiment.

For reference, <FIG> will be described with reference to <FIG> and <FIG>.

Referring to <FIG>, to enable efficient PSFCH transceiving operations in V2X communication, signaling may be mutually transmitted between a terminal <NUM>, which may be for example a transmitting terminal, and a base station <NUM>.

To begin with, at operation S100, to enable the efficient PSFCH transceiving operations, the terminal <NUM> may signal a maximum number of PSFCHs, which can be received during one TTI, to the base station <NUM>. In embodiments, the maximum number of PSFCHs which may be received during one TTI may be referred to as a maximum PSFCH receiving capability F, or a max PSFCH receiving capability F.

Specifically, the processor <NUM> may control the transceiver <NUM> to signal the max PSFCH receiving capability F to the base station <NUM>.

Here, the TTI may include a slot, and the max PSFCH receiving capability F may include the number of PSFCHs received in at least one of a groupcast and a unicast. That is, the max PSFCH receiving capability F may include a total number of PSFCH received in each of the groupcast and the unicast or include only the number of PSFCHs received in the groupcast or the unicast. Thus, the max PSFCH receiving capability F may be, for example, any one of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

At operation S150, when the base station <NUM> receives signals for information about the max PSFCH receiving capability F from the terminal <NUM>, the base station <NUM> may set sidelink communication of the terminal <NUM> to satisfy the following inequality: F ≥ L × M × N.

For reference, F may refer to a maximum number of PSFCHs, which can be received during one slot, and L may refer to the number of PSSCHs transmitted in the groupcast during each slot. Also, M may refer to the number of receiving terminals included in the same group, for example a group of terminals for a groupcast, as the transmitting terminal, and N may refer to a PSFCH receiving period.

That is, to enable efficient PSFCH transceiving operations, the base station <NUM> may determine the values L, M, and N associated with the terminal <NUM> considering the maximum PSFCH receiving capability F. Also, the base station <NUM> may further consider the following methods in a groupcast mode to satisfy the inequality presented above.

Moreover, at operation S200, to enable efficient PSFCH transceiving operations, the terminal <NUM> may signal a maximum number of PSFCHs, which can be transmitted during one TTI, to the base station <NUM>. In embodiments, the maximum number of PSFCHs which may be transmitted during one TTI may be referred to as a maximum PSFCH transmission capability R, or a max PSFCH transmission capability R.

Specifically, the processor <NUM> may control the transceiver <NUM> to signal the max PSFCH transmission capability R to the base station <NUM>.

Here, the TTI may include a slot, and the max PSFCH transmission capability R may include the number of PSFCHs transmitted in at least one of a groupcast and a unicast. That is, the max PSFCH transmission capability R may include a total number of PSFCHs transmitted in each of the groupcast and the unicast or include only the number of PSFCH transmitted in the groupcast or the unicast. Thus, the max PSFCH transmission capability R may be, for example, any one of, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

For reference, operation S200 may be performed before operation S100 or operations S100 and S200 may be performed simultaneously. Also, the terminal <NUM> may perform only one of operations S100 and S200, and the base station <NUM> may perform only a specific operation S150 or S250, or only a portion of operations S150 or S250, according to the operation performed by the terminal <NUM>. However, for brevity, an example embodiment pertains an example in which operation S200 is performed after operation S100 and the terminal <NUM> performs both operations S100 and S200.

When the base station <NUM> receives signaling information about the max PSFCH transmission capability R from the terminal <NUM>, at operation S250 the base station <NUM> may set the sidelink communication of the terminal <NUM> to satisfy the following inequality: U + G ≥ R.

For reference, U may refer to the number of PSSCHs received in the unicast during one slot, and G may refer to the number of PSSCHs received in the groupcast during one slot. Also, R may refer to a maximum number of PSFCHs, which can be transmitted during one slot.

That is, to enable efficient PSFCH transceiving operations, the base station <NUM> may determine a unicast and/or a groupcast to which the terminal <NUM> may belong, by considering the max PSFCH transmission capability R based on the inequality U + G ≥ R. Also, to satisfy the inequality above, the base station <NUM> may prioritize the unicast and the groupcast and determine R receiving channels, for example R receiving channels that may be received in the unicast and the groupcast, as receiving channels of the terminal <NUM> according to the order of higher priority.

As described above, due to the above-described processes, at operation S300 the base station <NUM> may perform RRC signaling to the terminal <NUM> based on the signaling received from the terminal <NUM>. Thus, the base station <NUM> may perform a scheduling operation for sidelink communication of the terminal <NUM> or perform groupcast-related setting operations of, for example, selecting a leader in a group and setting a size of a zone for a groupcast.

As described above, signaling may be mutually transmitted between the terminal <NUM> and the base station <NUM> to enable efficient PSFCH transceiving operations in the V2X communication. Hereinafter, a PSFCH determination method of a terminal in V2X communication, according to an example embodiment, examples of which will be described with reference to <FIG> and <FIG>.

<FIG> is a flowchart of a PSFCH determination method of a terminal, according to an example embodiment. <FIG> is a detailed flowchart of operations S1200 and S1300 of <FIG>, according to an example embodiment.

For reference, <FIG> and <FIG> will be described with reference to <FIG> and <FIG>.

Referring to <FIG>, to begin with, at operation S1000 k PSFCHs (where k is an integer greater than <NUM>) may be selected from all PSFCHs received during one TTI, and RSRPs or SINRs of the selected k PSFCHs may be measured.

Specifically, the processor <NUM> may select the k PSFCHs from all the PSFCHs, based on a preset specific criterion or randomly. Also, the processor <NUM> may control the transceiver <NUM> to sequentially measure RSRPs or SINRs of the k PSFCHs (where k is an integer greater than <NUM>), from among all the PSFCHs received during one TTI.

For reference, the processor <NUM> may control the transceiver <NUM> to sequentially measure the RSRPs or SINRs of the k PSFCHs after all the k PSFCHs are selected. In embodiments, whenever one PSFCH is selected, the processor <NUM> may control the transceiver <NUM> to immediately measure an RSRP or SINR of the selected PSFCH.

Here, k may be preset by a manufacturer or a user of the terminal <NUM> based on at least one of a channel state of the terminal <NUM>, performance of the terminal <NUM>, and a total number of PSFCHs. Also, for example, when a base station, for example base station <NUM> in <FIG>, sets a sidelink, the terminal <NUM> may be guided to set k as any one of values within a specific range.

When the RSRPs or SINRs of the selected k PSFCHs are sequentially measured, at operation S1100 the k PSFCHs may be sorted in ascending order based on the measured RSRPs or SINRs.

Specifically, the processor <NUM> may sort the k PSFCHs in the ascending order based on the RSRPs or SINRs of the k PSFCHs measured by the transceiver <NUM>. When the sorting of the k PSFCHs in the ascending order is completed, at operation S1200 it may be sequentially determined whether the k PSFCHs, which are sorted, are HARQ ACK or NACK in ascending order, and at operation S1300 it may be determined whether a PSSCH is to be retransmitted based on the determination result.

Specifically, the processor <NUM> may control the transceiver <NUM> to sequentially determine whether the k PSFCHs, which are sorted, are HARQ ACK or NACK in the ascending order. Also, the processor <NUM> may determine whether the PSSCH is to be retransmitted based on the determination result.

For reference, the HARQ ACK/NACK determination operation may be performed by a channel decoder of the transceiver <NUM>, for example the channel decoder included in the other components <NUM> of <FIG>.

<FIG> specifically illustrates examples of operations S1200 and S1300, according to an embodiment.

Specifically, referring to <FIG>, operation S1200 may start with operation S1210 of determining whether an m-th PSFCH ( where <NUM>≤m (integer) ≤k), from among the k PSFCHs that are sorted, is HARQ ACK or NACK.

Thus, if it is determined at operation S1220 that the m-th PSFCH (where <NUM>≤m (integer) ≤k), from among the k PSFCHs that are sorted, is HARQ ACK, it may be determined at operation S1320 whether m is less than k. Based on a result of the determination of operation S1320, the HARQ ACK/NACK determination operation on m+<NUM>-th to k-th PSFCHs, from among the k PSFCHs that are sorted, may proceed (return to operation S1210) or the HARQ ACK/NACK determination operation on the k PSFCHs that are sorted may end (proceed to operations S1330 to S1350).

For example, when m is less than k, for example when there is at least one PSFCH on which the HARQ ACK/NACK determination operation is not performed, from among the k PSFCHs that are sorted, the HARQ ACK/NACK determination operation may be sequentially performed on the m+<NUM>-th to k-th PSFCHs at operation S1210.

Otherwise, when m is equal to k, for example when the HARQ ACK/NACK determination operation on the k PSFCHs that are sorted is completely performed, the HARQ ACK/NACK determination operation on the k PSFCHs that are sorted may end, and it may be determined whether an operation of measuring RSRPs or SINRs of next k PSFCHs is to proceed, depending on whether there is at least one PSFCH on which the HARQ ACK/NACK determination operation is not performed, from among all the PSFCHs by proceeding to operations S1330 to S1350.

Specifically, at operation S1330, when there is at least one PSFCH on which the HARQ ACK/NACK determination operation is not performed, from among all the PSFCHs, the operation of measuring the RSRPs or the SINRs of the next k PSFCHs may proceed at operation S1340. In this case, operations S1100 to S1300 described above may be sequentially performed on the next k PSFCHs. Otherwise, at operation S1330, when there is no PSFCH on which the HARQ ACK/NACK determination operation is not performed, from among all the PSFCHs, the HARQ ACK/NACK determination operation on all the PSFCHs may end at operation S1350.

Moreover, at operation S1220 when it is determined that the m-th ( where <NUM>≤m (integer) ≤k) PSFCH, from among the k PSFCHs that are sorted, is HARQ NACK, the HARQ ACK/NACK determination operation on the m+<NUM>-th to k-th PSFCHs, from among the k PSFCHs that are sorted, may be interrupted, and it is determined that the PSSCH is to be retransmitted at operation S1310.

For reference, if it is determined that the PSSCH is to be retransmitted, all PSSCHs, for example all PSSCHs corresponding to all the PSFCHs, may be retransmitted. Also, operations S1210 to S1350 described above may be performed by the processor <NUM> and the transceiver <NUM>.

Specifically, in a PSFCH determination method of the terminal <NUM>, according to an example embodiment, a completion of the measuring of the RSRPs or SINRs of the selected k PSFCHs (refer to operation S1000) may not be followed by selecting new k PSFCHs again from the remaining PSFCHs, but a subsequent processing operation, for example an ACK/NACK determination operation, on the selected k PSFCHs in operation S1000 may be performed before the new k PSFCHs are selected. Thus, the complexity of the ACK/NACK determination operation may be reduced as compared to a case in which it is determined whether all the PSFCHs are ACK or NACK at once, and a processing time and a memory required for the ACK/NACK determination operation may be reduced. In addition, NACK may be rapidly determined because a PSFCH having a low RSRP or SINR, from among the selected k PSFCHs, is first determined as ACK or NACK.

As described above, a PSFCH determination method of a terminal according to an example embodiment, may be performed. Hereinafter, an example of a PSFCH determination method of a terminal, according to another example embodiment, will be described with reference to <FIG> and <FIG>.

<FIG> is a flowchart of a PSFCH determination method of a terminal, according to an example embodiment. <FIG> is a detailed flowchart of operation S2000 of <FIG>.

Referring to <FIG>, to begin with, at operation S2000 RSRPs or SINRs of all PSFCHs, which are received during one TTI, may be measured, and k PSFCHs that satisfy the preset criterion may be selected from the PSFCHs of which the RSRPs or SINRs are measured. Here, k may be an integer greater than <NUM>.

Specifically, the processor <NUM> may control the transceiver <NUM> to sequentially measure RSRPs or SINRs of all the PSFCHs received during one TTI. When the number of PSFCHs that satisfy the preset criterion, from among the PSFCHs of which the RSRPs or SINRs are measured, reaches k, the selecting operation, for example operation S2000, may end.

<FIG> specifically illustrates an example of operation S2000.

Specifically, referring to <FIG>, operation S2000 may start with operation S2010 of measuring an RSRP or SINR of an n-th PSFCH ( where n is a positive integer less than a total number of PSFCHs).

Thus, at operation S2010, when the RSRP or SINR of the n-th PSFCH (where n is a positive integer less than the total number of PSFCHs) is measured, it may be determined at operation S2020 whether the n-th PSFCH satisfies a preset criterion.

If it is determined that the n-th PSFCH satisfies the preset criterion, at operation S2030 a cumulative count of PSFCHs that satisfy the preset criterion may be incremented by <NUM>. At operation S2040, when the cumulative count, which is incremented by <NUM>, for example the number of PSFCHs that satisfy the preset criterion, is equal to k, operation S2100 of <FIG> may be performed. When the cumulative count, which is incremented by <NUM>, for example the number of PSFCHs that satisfy the preset criterion, is less than k, operation S2010 of measuring an RSRP or SINR of the next PSFCH, for example an n+<NUM>-th PSFCH, may be performed.

Even when it is determined that the n-th PSFCH does not satisfy the preset criterion, operation S2010 of measuring the RSRP or SINR of the next PSFCH, for example the n+<NUM>-th PSFCH, may be performed.

For reference, various criteria may be present, and methods of selecting k PSFCHs based on each criterion may be as follows.

Herein, each of k and the reference value may be preset by a manufacturer or a user of the terminal <NUM> based on at least one of a channel state of the terminal <NUM>, performance of the terminal <NUM>, and a total number of PSFCHs. Also, for example, when a base station, for example base station <NUM> in <FIG>, sets a sidelink, the terminal <NUM> may be guided to set k as any one of values within a specific range.

Referring back to <FIG>, when the k PSFCH are selected at operation S2000, the selected k PSFCHs may be sorted in ascending order based on measured RSRPs or SINRs at operation S2100.

Specifically, the processor <NUM> may sort the k PSFCHs in the ascending order, based on the RSRPs or SINRs of the respective PSFCHs measured by the transceiver <NUM>.

When the sorting of the k PSFCHs in the ascending order is completed, it may be sequentially determined whether the k PSFCHs, which are sorted, may be HARQ ACK or NACK in ascending order at operation S2200, and it may be determined whether a PSSCH is to be retransmitted based on the determination result at operation S2300.

For reference, because operations S2100 to S2300 may correspond to operations S1100 to S1300 described above with reference to <FIG> and <FIG>, detailed descriptions thereof are omitted.

As described above, the PSFCH determination method of the terminal, according to an example embodiment, may be performed. Hereinafter, a wireless communication device, which is implemented according to an embodiment, will be described with reference to <FIG>.

<FIG> is a block diagram of a wireless communication device <NUM> according to an embodiment.

For reference, the wireless communication device <NUM> of <FIG> may be applied to a base station, for example base station <NUM> in <FIG>; eNB, gNB, and AP, or a terminal, for example terminals <NUM> or <NUM> in <FIG>; STA, MS, and UE, which is implemented according to embodiments. Furthermore, in some embodiments, the wireless communication device <NUM> of <FIG> may operate in a standalone (SA) mode or a non-standalone (NSA) mode.

Specifically, the wireless communication device <NUM> implemented in a network environment <NUM> is illustrated in <FIG>.

The wireless communication device <NUM> may include a bus <NUM>, a processor <NUM>, a memory <NUM>, an input/output (I/O) interface <NUM>, a display module <NUM>, and a communication interface <NUM>. In another case, the wireless communication device <NUM> may omit at least one of the components described above or may further include at least one other component. However, for brevity, an example embodiment pertains an example in which the wireless communication device <NUM> includes the components described above.

The bus <NUM> may connect the processor <NUM>, the memory <NUM>, the I/O interface <NUM>, the display module <NUM>, and the communication interface <NUM> to each other. Thus, signals, for example control messages and/or data, may be exchanged and transmitted among the processor <NUM>, the memory <NUM>, the I/O interface <NUM>, the display module <NUM>, and the communication interface <NUM> through the bus <NUM>.

The processor <NUM> may include at least one of a central processing unit (CPU), an application processor (AP), and a communication processor (CP). Also, the processor <NUM> may perform operations or data processing operations related to the control and/or communication of other components of the wireless communication device <NUM>. In embodiments, the processor <NUM> may be a component including functions of the processor <NUM> of <FIG>.

The memory <NUM> may include a volatile memory and/or a non-volatile memory. Also, the memory <NUM> may store commands or instructions or data, which are associated with other components in the wireless communication device <NUM>.

In addition, the memory <NUM> may store software and/or a program <NUM>. The program <NUM> may include, for example, a kernel <NUM>, middleware <NUM>, an application programming interface (API) <NUM>, an application program <NUM> (also referred to as an "application"), and network access information <NUM>.

For reference, at least some of the kernel <NUM>, the middleware <NUM>, and the API <NUM> may be called an operating system (OS). Also, in embodiments the memory <NUM> may be a component including functions of the memory <NUM> of <FIG>.

For example, the I/O interface <NUM> may transmit commands or data, which are received from a user or another external device, to other components of the wireless communication device <NUM>. Also, the I/O interface <NUM> may output commands or data, which are received from other components of the wireless communication device <NUM>, to a user or another external device.

The display module <NUM> may include, for example, a liquid crystal display (LCD), a light-emitting diode (LED) display, an organic LED (OLED) display, a micro electromechanical systems (MEMS) display, or an electronic paper display.

In addition, the display module <NUM> may display various contents, for example texts, images, videos, icons, or symbols, to the user. The display module <NUM> may include a touch screen and receive a touch, a gesture, proximity, or a hovering input by using, for example, an electronic pen or a user's body part.

The communication interface <NUM> may set communication between the wireless communication device <NUM> and an external device, for example electronic devices <NUM> and <NUM> or a server <NUM>. For example, the communication interface <NUM> may be connected to a network <NUM> through wireless communication or wired communication and communicate with an external device, for example the electronic device <NUM> or the server <NUM>. Also, the communication interface <NUM> may communicate with an external device, for example the electronic device <NUM>, through wireless communication <NUM>. In addition, the communication interface <NUM> may be a component including functions of the transceiver <NUM> of <FIG>.

For reference, the wireless communication <NUM> may be a cellular communication protocol and use, for example, at least one of NR, LTE, LTE-A, CDMA, WCDMA, a universal mobile telecommunication system (UMTS), wireless broadband (WiBro), and GSM. In addition, the wired communication may include, for example, at least one of a universal serial bus (USB), a high-definition multimedia interface (HDMI), recommended standard <NUM> (RS-<NUM>), and plain old telephone service (POTS).

Furthermore, the network <NUM>, which is a telecommunications network may include, for example, at least one of a computer network, for example local area network (LAN) or wide-area network (WAN), the Internet, and a telephone network.

Moreover, each of the electronic devices <NUM> and <NUM>, which are external devices, may be of the same type as or a different type from the wireless communication device <NUM>. Also, the server <NUM> may include a group of at least one server.

For reference, all or some of operations performed by the wireless communication device <NUM> may be performed by other external devices, for example the electronic devices <NUM> and <NUM> or the server <NUM>.

In addition, when the wireless communication device <NUM> needs to perform a function or a service automatically or by request, the wireless communication device <NUM> may perform the function or the service by itself or request other external devices, for example the electronic devices <NUM> and <NUM> or the server <NUM>, to perform a partial function or service. Also, the other external devices, for example the electronic devices <NUM> and <NUM> or the server <NUM>, may perform the requested function or service and transmit a result to the wireless communication device <NUM>. In this case, the wireless communication device <NUM> may perform the function or the service based on the received result or by additionally processing the received result.

For the above-described mechanism, for example, a cloud computing technique, a distributed computing technique, or a client-server computing technique may be applied to the wireless communication device <NUM>.

According to the embodiments described above, an excess of PSFCH receiving capability and an overload of an operation of determining whether PSFCHs are ACK or NACK may be solved by transmitting signaling for the max PSFCH transceiving capability and using an efficient ACK/NACK determination method of PSFCHs. Thus, the performance and operational efficiency of the terminal may be improved.

Claim 1:
A terminal (<NUM>) configured to perform vehicle-to-everything communication, the terminal (<NUM>) comprising:
a transceiver (<NUM>) configured to transmit and receive one or more wireless signals; and
a processor (<NUM>) configured to:
control the transceiver (<NUM>) to measure reference signal received powers, RSRPs, or signal-to-interference & noise ratios, SINRs, of each one of a group of k physical sidelink feedback channels, PSFCHs, from among a plurality of PSFCHs received during one time transmission interval, TTI, wherein k is an integer greater than <NUM>,
sort the k PSFCHs, based on the RSRPs or the SINRs, in ascending order,
control the transceiver (<NUM>) to perform a sequential determination of whether the sorted k PSFCHs are a hybrid automatic repeat request, HARQ, acknowledgement, ACK, or a HARQ negative-acknowledgement, NACK, in the ascending order, and
determine whether a physical sidelink shared channel, PSSCH, is to be retransmitted, based on the sequential determination.