KR20230060471A - Sidelink communication method and apparatus - Google Patents

Abstract

Disclosed are a method for controlling timing in a wireless communication system and an apparatus thereof. According to one embodiment of the present invention, the method for controlling timing, which is performed by a first distributed unit (DU) including a processor and a modulator and demodulator (MODEM) in a base station supporting function division, comprises: a step of acquiring first time information from a central unit (CU) included in the base station; a step of acquiring synchronization information with a first system based on the first time information; a step of checking the time in which a system frame number (SFN) is changed based on the synchronization information; a step of generating a first timing control signal including a signal for directing, when the SFM is changed, the changed SFN and a first tick signal which has a cycle identical to the changing cycle of the SFN; and a step for providing the first timing control signal to the MODEM. Therefore, the stable side-link communication may be guaranteed.

Description

Side link communication method and apparatus {SIDELINK COMMUNICATION METHOD AND APPARATUS}

The present invention relates to sidelink communication providing direct communication between terminals, and more particularly, to a method and apparatus for open loop power control through sidelink control channel transmission power ramping.

In 2016, the International Telecommunication Union - Frequency Class (hereafter ITU-R) announced the vision and requirements of the 5th generation mobile communication. Requested development of standards. These three core services are enhanced Mobile BroadBand (eMBB; hereinafter eMBB), which provides high-speed data, Ultra-high Reliable and Low Latency Communication (URLLC), and large-scale things. It consists of massive Internet-of-Things (hereinafter referred to as mMTC), and requirements are individually defined for each service. As described above, the reason why ITU-R specified three core services was to prepare in advance in the standard specification as convergence between numerous other industries and mobile communication emerged in the 5G mobile communication era.

In the 5th generation mobile communication, there is a demand for a method for providing stable communication during side link communication.

The present disclosure provides a method and apparatus for securing stable sidelink communication through open loop power control through sidelink control channel (PSCCH) transmission power ramping during sidelink communication that provides direct communication between terminals.

In addition, the present disclosure provides a method and apparatus for sidelink control channel transmission power ramping.

In addition, the present disclosure provides a method and apparatus for solving the problem of increasing power consumption of a terminal during sidelink communication.

In addition, the present disclosure provides a method and apparatus for supporting high-speed transmit power ramping without increasing feedback resources during sidelink communication.

In addition, the present disclosure provides a method and apparatus capable of reducing the effect of uplink reception interference caused by sidelink communication.

A method according to an embodiment of the present disclosure for achieving the above object is a sidelink communication method in a first terminal, a first control for transmitting control information for the sidelink communication based on open loop power control determining a first power value of a channel; transmitting the control information through the first control channel having the first power value; determining a second power value of a first data channel for transmitting data when a response signal corresponding to the control information is received; and transmitting a second control channel and the first data channel in one predetermined slot for the sidelink communication, wherein the third power value of the second control channel and the first data channel The second power value of may be determined based on at least the power value of the first control channel.

Also, according to an embodiment of the present disclosure, when the second power value and the third power value are determined, open loop power control information at a transmission time of the first data channel may be further used.

In addition, according to an embodiment of the present disclosure, when a response signal corresponding to the control information is not received, transmitting the control information through a third control channel until a preset condition is satisfied; further comprising, The power value of the third control channel may be increased by a predetermined value from the power value of the first control channel.

Also, according to an embodiment of the present disclosure, the preset condition may include the number of transmissions of the control channel.

In addition, according to an embodiment of the present disclosure, when the power value of the third control channel increases and exceeds a preset maximum power, the power value of the third control channel may be determined as a preset power value.

In addition, according to an embodiment of the present disclosure, the response signal corresponding to the control information includes an acknowledgment (ACK) indicating success of demodulation and decoding of the control information, and a response signal indicating failure of demodulation and decoding of the control information. It may include one of negative acknowledgments (NACK).

Also, according to an embodiment of the present disclosure, when the negative response is received, the third power value may be increased by a preset value.

In addition, according to another embodiment of the present disclosure, as a sidelink communication method in a first terminal, transmitting control information for the sidelink communication to a plurality of receiving terminals through a first control channel; When a response signal corresponding to the first control channel is received from a first receiving terminal among the plurality of receiving terminals, a second control channel and a first data channel are transmitted in one predetermined slot for the sidelink communication. doing; A response signal corresponding to the second control channel and the first data channel is received from the first receiving terminal, and a response corresponding to the second control channel or a response signal corresponding to the second control channel is received from at least one of other receiving terminals. Excluding the first receiving terminal from the terminals to receive the sidelink data when the response signal corresponding to the first data channel is not received; Transmitting the control information through a third control channel; And when a response signal corresponding to the third control channel is received from a second receiving terminal among the plurality of receiving terminals, a fourth control channel and a second data channel are transmitted in one predetermined slot for the sidelink communication. It may include, and the first data channel and the second data channel may transmit the same sidelink data.

In addition, according to an embodiment of the present disclosure, a response signal corresponding to the second control channel and the first data channel is received from the first receiving terminal, and the second control channel and the first data channel are received from a third receiving terminal. When a response signal corresponding to the data channel is received, further excluding the third receiving terminal from the terminals to receive the sidelink data; may further include.

In addition, according to an embodiment of the present disclosure, a response signal corresponding to the second control channel and the first data channel is received from the first receiving terminal, and a response to the second control channel is received from a third receiving terminal. If received, transmitting a fifth control channel and a third data channel; may further include, wherein the third data channel transmits the same sidelink data as the first data channel and the second data channel. can

In addition, according to an embodiment of the present disclosure, the first power value of the first control channel is determined based on open loop power control, and the second power value of the first data channel and the third power value of the second control channel are determined based on open loop power control. A power value, the fourth power value of the third control channel is determined based on the transmit power of the first control channel, and the fifth power value of the fourth control channel and the sixth power value of the second data channel may be determined based on the fourth power value.

In addition, according to an embodiment of the present disclosure, when there is no response from all of the plurality of receiving terminals, transmitting the control information through a third control channel until a preset condition is satisfied; further comprising, The power value of the third control channel may be increased by a predetermined value from the power value of the first control channel.

In addition, according to an embodiment of the present disclosure, the preset condition includes the number of transmissions of the control channel, and when the power value of the third control channel increases and exceeds the preset maximum power, the preset power value is set to the third control channel. 3 The power value of the control channel can be determined.

In addition, an apparatus according to an embodiment of the present disclosure is a first terminal for sidelink communication, and includes a sidelink receiving unit for receiving a sidelink signal from another terminal; a side link transmission unit for transmitting a side link signal to another terminal; and a controller including at least one processor, wherein the controller:

Determines a first power value of a first control channel for transmitting control information for the sidelink communication based on open loop power control, and transmits the control information through the first control channel having the first power value Controls the sidelink transmission unit to transmit, determines a second power value of a first data channel for transmitting data when a response signal corresponding to the control information is received from the sidelink reception unit, and the sidelink communication Controls the sidelink transmission unit to transmit a second control channel and the first data channel in one predetermined slot for

The third power value of the second control channel and the second power value of the first data channel may be determined based on at least the power value of the first control channel.

In addition, according to an embodiment of the present disclosure, when determining the second power value and the third power value, the controller may further use open loop power control information at the transmission time of the first data channel.

In addition, according to an embodiment of the present disclosure, the controller transmits the control information through a third control channel until a preset condition is satisfied when a response signal corresponding to the control information is not received. The transmission unit may be further controlled, and the power value of the third control channel may be increased by a predetermined value from the power value of the first control channel.

Also, according to an embodiment of the present disclosure, the preset condition may include the number of transmissions of the control channel.

In addition, according to an embodiment of the present disclosure, the controller may determine the power value of the third control channel as a preset power value when the power value of the third control channel exceeds a preset maximum power when the power value increases. .

In addition, according to an embodiment of the present disclosure, the response signal corresponding to the control information includes an acknowledgment (ACK) indicating success of demodulation and decoding of the control information, and a response signal indicating failure of demodulation and decoding of the control information. It may include one of negative acknowledgments (NACK).

Also, according to an embodiment of the present disclosure, when the negative response is received, the third power value may be increased by a preset value.

According to the present disclosure, in 5G NR sidelink communication, by realizing open-loop power control through sidelink control channel (PSCCH) transmission power ramping, resource consumption and terminal power consumption increase, and uplink reception interference effect increases etc., and has the advantage of securing stable sidelink communication.

1 is an exemplary diagram for explaining a 5G NR-based sidelink service scenario.
2 is an exemplary diagram according to the first embodiment of a 5G NR-based sidelink slot format.
3 is an exemplary diagram according to a second embodiment of a 5G NR-based sidelink slot format.
4 is an exemplary diagram according to a third embodiment of a 5G NR-based sidelink slot format.
5 is an exemplary diagram according to a fourth embodiment of a 5G NR-based sidelink slot format.
6 is an exemplary diagram for explaining each case of a transmitting terminal and a receiving terminal in sidelink transmission according to the present disclosure.
7 is a diagram illustrating an embodiment of a sidelink channel transmission scenario of 5G NR.
8 is a diagram illustrating another embodiment of a sidelink channel transmission scenario of 5G NR.
9 is a flowchart illustrating an operation between a transmitting terminal and a receiving terminal during sidelink control channel transmission power ramping according to the present disclosure.
10A is an exemplary view of a part for explaining channel transmission power ramping when a transmitting terminal transmits a sidelink control channel according to an embodiment of the present disclosure.
FIG. 10B is an exemplary diagram for explaining channel power ramping when a transmitting terminal transmits a sidelink control channel in succession to FIG. 10A according to an embodiment of the present disclosure.
11 is an exemplary diagram for explaining resource use in a sidelink channel transmission scenario according to an embodiment of the present disclosure.
12A is an exemplary view of a portion for explaining channel transmission power ramping when a transmitting terminal transmits a sidelink control channel according to an embodiment of the present disclosure.
FIG. 12B is an exemplary diagram for explaining channel power ramping when a transmitting terminal transmits a sidelink control channel, continuing from FIG. 12A according to an embodiment of the present disclosure.
13A is an exemplary view of a portion for explaining channel transmission power ramping when a transmitting terminal transmits a sidelink control channel according to an embodiment of the present disclosure.
FIG. 13B is an exemplary diagram for explaining channel power ramping when a transmitting terminal transmits a sidelink control channel in succession to FIG. 13A according to an embodiment of the present disclosure.
14 is an exemplary diagram for explaining a case in which one transmitting terminal and three receiving terminals exist in a groupcast communication mode according to an embodiment of the present disclosure.
15 is an exemplary view for explaining a case in which one transmitting terminal and three receiving terminals exist in a groupcast communication mode according to another embodiment of the present disclosure.
16 is a partial block diagram of a terminal using transmit power ramping of a sidelink control channel providing direct communication between terminals according to the present disclosure.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, they should not be interpreted in an ideal or excessively formal meaning. don't

A communication system to which embodiments according to the present invention are applied will be described. A communication system to which embodiments according to the present invention are applied is not limited to the contents described below, and embodiments according to the present invention can be applied to various communication systems. Here, the communication system may be used in the same sense as a communication network.

Throughout the specification, a network refers to, for example, wireless Internet such as WiFi (wireless fidelity), portable Internet such as WiBro (wireless broadband internet) or WiMax (world interoperability for microwave access), and GSM (global system for mobile communication). ) or CDMA (code division multiple access) 2G mobile communication networks, WCDMA (wideband code division multiple access) or CDMA2000 3G mobile communication networks, HSDPA (high speed downlink packet access) or HSUPA (high speed uplink packet access) It may include a 4G mobile communication network such as a 3.5G mobile communication network, a long term evolution (LTE) network or an LTE-Advanced network, and a 5G mobile communication network.

Throughout the specification, a terminal includes a mobile station, a mobile terminal, a subscriber station, a portable subscriber station, a user equipment, and an access terminal. It may refer to a terminal, a mobile station, a mobile terminal, a subscriber station, a mobile subscriber station, a user device, an access terminal, or the like, and may include all or some functions of a terminal, a mobile station, a mobile terminal, a subscriber station, a mobile subscriber station, a user equipment, an access terminal, and the like.

Here, a desktop computer capable of communicating with a terminal, a laptop computer, a tablet PC, a wireless phone, a mobile phone, a smart phone, and a smart watch (smart watch), smart glass, e-book reader, PMP (portable multimedia player), portable game device, navigation device, digital camera, DMB (digital multimedia broadcasting) player, digital voice digital audio recorder, digital audio player, digital picture recorder, digital picture player, digital video recorder, digital video player ) can be used.

Throughout the specification, a base station includes an access point, a radio access station, a node B, an evolved nodeB, a base transceiver station, and an MMR ( It may refer to a mobile multihop relay)-BS, and may include all or some functions of a base station, access point, wireless access station, NodeB, eNodeB, transmission/reception base station, MMR-BS, and the like.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate overall understanding in the description of the present invention, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

In 2016, the International Telecommunication Union - Frequency Class (hereafter ITU-R) announced the vision and requirements of the 5th generation mobile communication. Requested development of standards. These three core services are enhanced Mobile BroadBand (eMBB; hereinafter eMBB), which provides high-speed data, Ultra-high Reliable and Low Latency Communication (URLLC), and large-scale things. It consists of massive Internet-of-Things (hereinafter referred to as mMTC), and requirements are individually defined for each service. As described above, the reason why ITU-R specified three core services was to prepare in advance in the standard specification as convergence between numerous other industries and mobile communication emerged in the 5G mobile communication era.

To realize this, 3GPP moves various services by enabling realization of network slicing based on Software-Defined Networking (SDN)/Network Function Virtualization (NFV) in the core network standard. A framework that can be provided in a communication network has been prepared. In addition, in order to realize requirements such as low latency, a mobile edge computing (MEC) structure in which the core network is adjacent to the RAN base station is reflected.

On the other hand, in order to support services required in various industrial fields, attempts are being made to utilize 5G mobile communication as an infrastructure that provides new convergence services based on three core services. However, these attempts remain at the level of demonstration projects and have yet to lead to specific large-scale results. The cause is due to competition among industry players for leadership in convergence services, lack of technological maturity in the early stages of commercialization of 5G, and security concerns in other industries about data generated from convergence services.

Representative convergence services with other industries are vehicle-related convergence services. To this end, 3GPP, an international standardization organization for mobile communication, first introduced Direct Device-to-Device Communication for proximity service using cellular technology in the Release 12 standard. And, using this technology, LTE (Cellular) based vehicle communication (C-V2X; C-V2X) technology was adopted in Release 14. Subsequently, 3GPP developed 5G NR-based cellular-based vehicle communication technology in Release 16 through Release 15.

With 5G NR-based C-V2X (Release 16), the concept of sidelink was introduced. This is a link set up to perform direct communication between terminals (vehicles) without going through a network. The technology was developed so that it can be used for various convergence services that require direct communication between terminals. Hereinafter, as a prior art, the characteristics of the sidelink physical layer among 5G NR V2X technologies will be briefly described.

1 is an exemplary diagram for explaining a 5G NR-based sidelink service scenario.

Referring to FIG. 1 , a first base station 11 forms a first coverage area 10 to provide services, and a second base station 21 forms a second coverage area 20 to provide services. The first base station 11 provides service through terminal A 12 within the first coverage 10, and the second base station 21 provides terminal B 22 and terminal C within the second coverage 20. The service is provided through (23). Device A 12 is synchronized with the first base station 11, and device B 22 and device C 23 are synchronized with the second base station 21 (Level-2).

Meanwhile, since the terminal D 31 is out of the range of the first coverage 10 and the second coverage 20, it cannot synchronize with the first base station 11 or the second base station 21. As shown in FIG. 1, device D (31) sets device A (12) as a reference synchronization (SyncRef) device, and device A (12) transmits a sidelink synchronization signal block (Sidelink Synchronization Signal Block; S -SSB) is used to synchronize (Level 3). Meanwhile, the terminal E 32 exists within the first coverage 10 of the first base station 11 or the second coverage 20 of the second base station 12 and is present in the first base station 11 or the second base station 21 Since it cannot be connected to terminals synchronized with , it is inevitably connected to a terminal that sets device A (12) or device B (22) as a reference synchronization terminal out of coverage, such as terminal D (31), to secure synchronization ( Level 7).

On the other hand, terminal F 42 is outside the range of the first coverage 10 and the second coverage 20, but can secure synchronization within the coverage 40 of the GNSS network 41 that provides absolute time synchronization (Level 5). In addition, terminal G 43 connected to terminal F 42 but out of the third coverage 40 sets terminal F 42 as a reference synchronization (SyncRef) terminal and transmits from terminal F 42. Synchronization is performed using the Sidelink Synchronization Signal Block (S-SSB) (Level 6).

Terminal G 51 uses terminal F 42 synchronized with the GNSS network, not a terminal synchronized with the first base station 11 like terminal A 12, as a reference synchronization terminal (Level 6). Terminal H 52 uses terminal G 51 as a reference synchronization terminal, which eventually exists outside the first coverage 10, the second coverage 20, and the GNSS coverage 40, and is inside the coverage It is similar to the terminal E 32 and has the same priority in terms of using terminals existing in and synchronizing within the corresponding coverage as reference synchronization terminals (Level 7).

On the other hand, if it does not belong to any coverage and there is no reference synchronization terminal, it may be necessary to use the terminal's own clock as a reference for synchronization, and terminal I 61 corresponds to this case. This case is a method that can be used when all the above conditions are not satisfied, and is actually used with the lowest priority (Level 8). However, terminal J 62 uses terminal I (I), which utilizes the clock inside the terminal as a synchronization signal, as a reference synchronization terminal, which has the same priority as terminal E 32 and terminal H 52. can (Level 7).

According to the 5G sidelink service scenario embodiment shown in FIG. 1, it can be confirmed that direct communication between terminals can be provided in 5G using sidelink in various situations. However, regardless of which synchronization signal is used by terminals performing direct communication for this purpose, synchronization between terminals must be secured and maintained. Based on this, hereinafter, a channel required for direct communication between devices using a practical 5G sidelink - in particular, a physical layer (hereinafter referred to as PHY) channel - will be described.

In the PHY channel used for 5G sidelink, PSSCH (Physical Sidelink Shared Channel) that actually transmits user data, signaling and a part (Second-Stage) of signaling and control signals (Sidelink Control Information (SCI)), etc., to receive the associated PSSCH PSCCH (Physical Sidelink Control Channel) that transmits a part of the necessary SCI (First Stage), and PSBCH that a reference synchronization terminal transmits to target terminals through S-SSB (Sidelink - Synchronization Signal Block) to acquire synchronization between communication terminals (Physical Sidelink Broadcast Channel), and PSFCH (Physical Sidelink Feedback Channel) for transmitting a feedback signal for H-ARQ (Hybrid Automatic Repeat Request) that provides high reliability of PSSCH transmission.

In addition, the reference signals used in the 5G sidelink include a de-modulation reference signal (DM-RS) for demodulation of the PSSCH, PSCCH, and PSBCH, and transmission to remove frequency errors and noise generated in high-frequency channels A phase tracking reference signal (PT-RS), which is used for channel state information, and a channel state information reference signal (CSI-RS) used for channel measurement for channel state information are included. And, in 5G sidelink, a sidelink primary synchronization signal (SPSS) and a sidelink secondary synchronization signal (SSSS) are included in the synchronization signal of the S-SSB.

Hereinafter, a slot format for transmitting the PHY channels, the reference signal, and the synchronization signals used in 5G sidelink will be briefly described.

2 is an exemplary diagram according to the first embodiment of a 5G NR-based sidelink slot format.

Referring to FIG. 2, the first embodiment of the 5G NR-based sidelink slot format illustrates a slot format using a normal cyclic prefix (CP) consisting of 14 symbols in one slot.

Looking specifically at the first embodiment of the sidelink slot format, the first OFDM symbol period may be an AGC period 111. The OFDM symbol of the AGC period 111 may be configured by copying a signal transmitted in the second OFDM symbol period in order to stably perform an automatic gain control (AGC) operation at the receiving side. In addition, the last OFDM symbol period is composed of a guard period 115 so that transmission and reception can be switched. In addition, in the 12 symbol intervals from the 2nd OFDM symbol interval to the 13th OFDM symbol interval, the DMRS 112 for demodulation can be arranged in units of 3 OFDM symbol intervals. Among the 3 OFDM symbols in the 12 symbol intervals, the remaining 2 OFDM symbol intervals in which the DMRS is not deployed are PSSCHs for substantially transmitting user data, signaling and a part (Second-Stage) of the signaling and control signal (Sidelink Control Information; SCI), etc. (113) can be placed. Here, the PSCCH 114 for transmitting a part (First Stage) of SCI necessary for receiving the PSSCH may be transmitted through a part of the 2nd to 4th OFDM symbol period, that is, a part of 3 OFDM symbol periods. .

In FIG. 2, since the DMRS arranged in every 3 OFDM symbol intervals is transmitted in the 2nd OFDM symbol interval, the DMRS can be transmitted in the 5th OFDM symbol interval, the 8th OFDM symbol interval, and the 11th OFDM symbol interval. Therefore, the PSSCH 113 is the 3rd OFDM symbol period, the 4th OFDM symbol period, the 6th OFDM symbol period, the 7th OFDM symbol period, the 9th OFDM symbol period, the 10th OFDM symbol period, the 12th OFDM symbol period, and the 13th OFDM symbol period. It can be transmitted in an OFDM symbol interval.

3 is an exemplary diagram according to a second embodiment of a 5G NR-based sidelink slot format.

Referring to FIG. 3, the second embodiment of the 5G NR-based sidelink slot format also illustrates a slot format using a Normal CP consisting of 14 symbols in one slot as in the first embodiment.

Looking specifically at the second embodiment of the sidelink slot format, the first OFDM symbol period may be an AGC period 121. The OFEM symbol of the AGC period 121 may be configured by copying a signal transmitted in the second OFDM symbol period in order to stably perform the AGC operation at the receiving side. In addition, the second to last OFDM symbol period is composed of a guard period 125 so that transmission and reception can be switched. And in the 11 symbol intervals from the 2nd OFDM symbol interval to the 12th OFDM symbol interval, a PSSCH 123 that substantially transmits user data, signaling and a part (Second-Stage) of the signaling and control signal (Sidelink Control Information; SCI), etc. and a DMRS 122 for demodulation. DMRS is transmitted in the 4th OFDM symbol interval and the 11th OFDM symbol interval. Among the 11 symbol intervals from the 2nd OFDM symbol interval to the 12th OFDM symbol interval, the PSSCH is transmitted in the remaining OFDM symbol intervals in which the DMRS is not transmitted. In addition, a PSCCH 124 transmitting a part (First Stage) of SCI necessary for receiving the PSSCH is transmitted in the second OFDM symbol period and part of the third OFDM symbol period.

4 is an exemplary diagram according to a third embodiment of a 5G NR-based sidelink slot format.

Referring to FIG. 4, in the third embodiment of the 5G NR-based sidelink slot format, a slot format using a Normal CP consisting of 14 symbols in one slot as in the first and second embodiments is exemplified are doing In FIG. 4, a slot format including a PSFCH is different from the previous embodiments.

Looking specifically at the third embodiment of the sidelink slot format, the first OFDM symbol period may be the first AGC period 131-1. The first AGC period 131-1 may be configured by copying a signal transmitted in the second OFDM symbol period in order to stably perform an automatic gain control (AGC) operation at the receiving side. Here, the first AGC period 131-1 may be an AGC period for transmitting the PSSCH. In addition, the 11th OFDM symbol period and the 14th OFDM symbol period are composed of guard periods 136-1 and 136-2 capable of switching transmission and reception, respectively. In addition, in the 9 OFDM symbol intervals from the 2nd OFDM symbol interval to the 10th OFDM symbol interval, a PSSCH (133 ) and the DMRS 132 for demodulation are located. DMRS is transmitted in the 4th OFDM symbol interval and the 9th OFDM symbol interval. PSSCH is transmitted in the remaining OFDM symbol intervals in which the DMRS is not transmitted among the 2nd to 10th OFDM symbol intervals. In addition, a PSCCH 134 transmitting a part (First Stage) of SCI necessary for receiving the PSSCH is transmitted in the second OFDM symbol period and part of the third OFDM symbol period.

Meanwhile, the sidelink slot format according to the third embodiment illustrated in FIG. 4 may be used for a slot for receiving a demodulation result from a receiving terminal that has received a PSSCH. Therefore, the first guard period 136-1 can be a period for switching between transmission and reception. In addition, the sidelink slot format according to the third embodiment may include a second AGC period 131-2 (PSFCH 135) and a second guard period 136-2 for automatic gain control. The OFDM symbol transmitted in the period 131-2 may be copied and transmitted as a PSFCH symbol to stabilize the AGC operation at the receiving side.In addition, the PSFCH 135 transmits the demodulation result of the PSSCH from the receiving terminal to the transmitting terminal. It can be configured by including feedback information The last OFDM symbol period can complete one sidelink slot format and become a second guard period 136-2 for the next operation.

5 is an exemplary diagram according to a fourth embodiment of a 5G NR-based sidelink slot format.

Referring to FIG. 5, in the fourth embodiment of the 5G NR-based sidelink slot format, a slot format using a Normal CP consisting of 14 symbols in one slot is exemplified in the same manner as in the first to third embodiments. are doing 5 illustrates a format for transmitting a Sidelink Primary Synchronization Signal (S-PSS) and a Sidelink Secondary Synchronization Signal (S-SSS) for synchronization in a 5G sidelink, unlike the previous embodiments.

Looking specifically at the fourth embodiment of the sidelink slot format, the PSBCH 141 transmitting a message including system parameters for the sidelink can be transmitted in the first OFDM symbol period. In addition, the S-PSS 142 may transmit in the second OFDM symbol interval and the third OFDM symbol interval. Here, the S-PSS 142 may be configured using one of two types of S-PSS sequences and transmitted using 127 sub-carriers. The S-SSS 143 can transmit in the 4th OFDM symbol interval and the 5th OFDM symbol interval. Here, the S-SSS 143 may be configured using one of 336 types of S-SSS sequences and transmitted using 127 sub-carriers. In the 6th to 13th OFDM symbol intervals, the PSBCH is transmitted, and in the last 14th OFDM symbol interval, one sidelink slot format is completed and a guard interval 144 for the next operation is configured.

6 is an exemplary diagram for explaining each case of a transmitting terminal and a receiving terminal in sidelink transmission according to the present disclosure.

In FIG. 6, two different transmitting terminals 261 and 271 are illustrated. Transmitting terminal A 261 may be a terminal adjacent to the base station 250, and transmitting terminal B 271 may be a terminal far from the base station. In addition, each of the transmitting terminal A 261 and the transmitting terminal B 271 may be terminals located within the coverage of the base station 250 .

The transmitting terminal A 261 may be a terminal that transmits a signal based on at least one of unicast, group cast, and broadcast. Similarly, the transmitting terminal B 271 may be a terminal that transmits a signal based on at least one of unicast, group cast, and broadcast.

The transmitting terminal A 261 may transmit a signal to the receiving terminal A1 262 and/or the receiving terminal A2 263. The transmitting terminal A 261 may communicate with the receiving terminal A1 262 by forming a sidelink coverage 260-1 for communication. In addition, the transmitting terminal A 261 can communicate with the receiving terminal A2 263 by forming a sidelink coverage 260-2 for communication.

In the same way, the transmitting terminal B 271 may transmit a signal to the receiving terminal B1 272 and/or the receiving terminal B2 273. Transmitting terminal B 271 can communicate by forming sidelink coverage 270-1 for communication with receiving terminal B1 272. In addition, the transmitting terminal B 261 can communicate with the receiving terminal B2 273 by forming a sidelink coverage 270-2 for communication.

Meanwhile, in a sidelink that provides direct communication between terminals, an open loop method is adopted as a power control method. Sidelink power control is applied to transmission of channels for sidelink required for sidelink, that is, PSCCH, PSSCH, PSFCH, and S-SSB. In addition, sidelink power control is applied to unicast transmission and groupcast transmission among sidelink communications, and is not applied to broadcast transmission.

In sidelink unicast transmission, PSSCH power control can be largely set to three modes.

1) A mode that considers only downlink path loss (path loss between the base station and the terminal, PL _DL ),

2) A mode that considers only sidelink path loss (path loss between a transmitting terminal and a receiving terminal, PL _SL ), and

3) It consists of a mode using both downlink path loss and sidelink path loss.

The first mode (mode that considers only downlink path loss) is a mode that can be applied when a terminal exists within network coverage, and serves to reduce the effect of interference on uplink reception at the base station according to sidelink transmission. . That is, through the first mode, transmitting terminals (terminals having a small downlink path loss) close to the base station transmit with less power than transmitting terminals far from the base station (terminals having a large downlink path loss).

For example, as shown in FIG. 6 , it is assumed that transmitting terminal A 261 operates in the first PSSCH power control mode while existing close to the coverage of the base station 250 . In this case, since the transmitting terminal A 261 forms the sidelink coverage A1 260-1 in consideration of the downlink path loss, communication with the receiving terminal A1 262 can succeed. However, communication with the receiving terminal A2 263 cannot succeed because of the transmission power determined based on the downlink path loss.

On the other hand, assuming that transmitting terminal B 271 operates in the first mode while being far away from the coverage of base station 250, transmitting terminal B 271 considers downlink path loss and uses sidelink coverage B2 (270- 2), communication with both the receiving terminal B1 272 and the receiving terminal B2 273 can succeed. However, the sidelink coverage B2 270-2 is much larger than the sidelink coverage B1 270-1 formed with the transmit power required by the receiving terminal B1 272.

Therefore, when using the first mode power control scheme of the sidelink, although there is an advantage of maintaining the effect of interference on uplink reception in terminals close to the base station, communication with receiving terminals outside the limited sidelink coverage may be difficult. there is. Conversely, when the first mode power control method is used, a problem of causing an increase in power consumption of the terminal may occur due to unnecessarily excessive transmission power of a terminal far from the base station.

Next, the second mode (a mode considering only sidelink path loss) will be described. The second mode is a mode that can be used both when the terminal exists within network coverage or when it exists outside network coverage. That is, this is a method of forming sidelink coverage by considering only sidelink path loss. Since the second mode determines the transmission power based on the path loss with the terminal to communicate with, the case where communication is difficult because the transmission power required for sidelink communication is used does not occur. There is a problem that can affect link reception with excessive interference.

For example, as shown in FIG. 6, when the transmitting terminal A 261 located close to the base station 250 operates in the second mode, it communicates with the receiving terminal A1 262 and the receiving terminal A2 263 ), it is possible to determine the required transmission power by considering the loss of each side link path. Therefore, sidelink coverage A1 260-1 required when transmitting terminal A 261 communicates with receiving terminal A1 262 and sidelink coverage A2 required when transmitting terminal A 261 communicates with receiving terminal A2 263 (260-2) is formed. Accordingly, the transmitting terminal A 261 uses more transmission power when communicating with the receiving terminal A2 263 than when communicating with the receiving terminal A1 262. When the transmitting terminal A 261 communicates with the receiving terminal A2 263, the uplink reception of the base station 250 has a larger interference effect.

On the other hand, assuming that the transmitting terminal B 271 is within the coverage of the base station 250 and operates in the second mode while being far from the base station 250, the case of communicating with the receiving terminal B1 272 and the receiving terminal B2 When communicating with (273), the required transmit power can be determined by considering the loss of each sidelink path. When the transmitting terminal B 271 communicates with the receiving terminal B2 273, the sidelink coverage 270-2 is the sidelink coverage 270-1 when the transmitting terminal B 271 communicates with the receiving terminal B1 272. ) is wider than In this way, when the transmitting terminal B 271 far from the base station uses the second mode power control method, the effect of interference on the uplink reception of the base station 250 is reduced, and sidelink communication can be smoothly provided. There are advantages.

As described above, the first and second modes of power control used in sidelink unicast transmission have advantages and disadvantages depending on the location of the transmitting terminal. It is preferable to perform sidelink power control using a mode using all sidelink path loss. That is, according to the location and path loss of the UE, the power control mode of the sidelink is configured to use both the downlink path loss and the sidelink path loss, and the best performance is to find the optimal method considering the location between the UEs. will appear.

Meanwhile, in sidelink groupcast transmission of 5G NR, PSSCH power control uses only a mode that considers only downlink path loss. The operation of open loop power control in groupcast is the same as the first mode in unicast transmission. In 5G NR, PSCCH, PSSCH, and PSFCH are used for sidelink transmission.

7 is a diagram illustrating an embodiment of a sidelink channel transmission scenario of 5G NR.

Referring to FIG. 7, an example in which PSSCHs for transmitting sidelink data are transmitted through different subchannels and PSFCHs for HARQ feedback are transmitted is illustrated. In addition, in the embodiment of FIG. 7, the number of PSSCH slots (N) associated with one PSFCH symbol is 4, and the number of subchannels allocated to the sidelink ( When L) is 3, the PSFCH period (N) is in units of 4 slots, and the minimum offset (K) of PSSCH slots associated with one PSFCH symbol is 2 One implementation of a sidelink channel transmission scenario of 5G NR example is shown.

Looking more specifically, a first subchannel will be described. PSSCH #01 (120-01) and PSSCH #02 (120-02) are sequentially transmitted through the first subchannel, and PSFCH symbols associated with PSSCHs transmitted in previous slots may be transmitted. In addition, PSSCH #03 (120-03), PSSCH #04 (120-04), PSSCH #01 (121-01), and PSSCH #02 (121-02) are transmitted through the first subchannel. In addition, PSFCH symbols associated with PSSCH #01 (120-01), PSSCH #02 (120-02), PSSCH #03 (120-03), and PSSCH #04 (120-04) are transmitted through the first subchannel. do. PSSCH #01 (120-01), PSSCH #02 (120-02), PSSCH #03 (120-03), PSSCH #04 (120-04), PSSCH #01 (121-04) transmitted through the first subchannel 01) and the PSCCHs 110-01, 110-02, 110-03, 110-04, 111-01, and 111-02 respectively corresponding to PSSCH #02 (121-02) are some symbols in corresponding slots. can be transmitted using

Looking at transmission in the second subchannel, PSSCH #05 (120-05) and PSSCH #06 (120-06) are sequentially transmitted through the second subchannel, and PSSCHs transmitted in previous slots are associated with PSSCHs. A PSFCH symbol may be transmitted. In addition, PSSCH #07 (120-07), PSSCH #08 (120-08), PSSCH #05 (121-05), and PSSCH #06 (121-05) are transmitted through the second subchannel. In addition, PSFCH symbols associated with PSSCH #05 (120-05), PSSCH #06 (120-06), PSSCH #07 (120-07), and PSSCH #08 (120-08) are transmitted through the second subchannel. do. PSSCH #05 (120-05), PSSCH #07 (120-07), PSSCH #08 (120-08), PSSCH #05 (121-05) and PSSCH #06 (121-05) transmitted through the second subchannel 06) PSCCHs 110-05, 110-07, 110-08, 111-05, and 111-06 corresponding to each may be transmitted using some symbols in corresponding slots.

PSSCH #06 (120-06) of the second subchannel may not have a corresponding PSCCH. The SCI associated with PSSCH #06 (120-06) may be transmitted through PSCCH #02 (110-02) corresponding to PSSCH #02 (120-02).

Regarding the third subchannel, PSSCH #09 (120-09) and PSSCH #10 (120-10) are sequentially transmitted through the third subchannel, followed by PSFCHs associated with PSSCHs transmitted in previous slots. Symbols can be transmitted. In addition, PSSCH #11 (120-11), PSSCH #12 (120-12), PSSCH #09 (121-09), and PSSCH #10 (121-10) are transmitted through the third subchannel. In addition, PSFCH symbols associated with PSSCH #09 (120-09), PSSCH #10 (120-10), PSSCH #11 (120-11), and PSSCH #12 (120-12) are transmitted through the third subchannel. do. As in the case of the first subchannel, PSSCH #09 (120-09), PSSCH #10 (120-10), PSSCH #11 (120-11), PSSCH #12 (120) transmitted through the third subchannel -12), PSCCHs 110-09, 110-10, 110-11, 110-12, 111-09, 111- corresponding to PSSCH #09 (121-09) and PSSCH #10 (121-10) respectively 10) may be transmitted using some symbols in corresponding slots.

Lastly, PSFCH symbols shown last in each subchannel may transmit HARQ feedback signals for providing high reliability to PSSCHs transmitted through each subchannel.

As described above, since the PSFCH periodicity is 4 slots, HARQ feedback signals for PSSCHs of 4 slots transmitted in a corresponding subchannel can be transmitted in one PSFCH period.

Summarizing the above, basically, one PSCCH and one PSSCH can be transmitted per PSSCH slot and subchannel, and there is a feedback symbol interval for transmitting the PSSCH reception result for each PSFCH period.

However, a case in which the PSCCH does not exist in every slot will be described. As illustrated in FIG. 7, PSSCH #06 (120-06) is located in a slot that does not transmit a corresponding PSCCH. SCI information corresponding to PSSCH #06 (120-06) may be transmitted through PSCCH #02 (110-02) located in the same slot and subchannel as PSSCH #02 (120-02).

Next, HARQ feedback will be reviewed. HARQ feedback may be allocated to PSFCHs 130-01 to 130-12 corresponding to associated slots in a corresponding subchannel. For example, feedback of the reception result of PSCCH #12 (110-12) and PSSCH #12 (120-12) may be transmitted through PSFCH #12 (130-12) as shown by reference numeral 701. This is transmitted through PSFCHs corresponding to each slot in the corresponding subchannel for each of PSSCH #02 (120-02) and PSSCH #06 (120-06) transmitted in conjunction with one PSCCH #02 (110-02). It can be. More specifically, the feedback of the reception result of PSSCH #02 (120-02) is transmitted through the PSFCH #02 (130-02) as shown by reference numeral 702, and the feedback of the reception result of PSSCH #06 (120-06) is As shown by reference numeral 703, it may be transmitted through PSFCH #06 (130-06). As such, each of the PSFCHs 130-01 to 130-12 may provide feedback on the reception state of the PSSCH and/or PSCCH transmitted through one slot in a corresponding subchannel.

According to the configuration of FIG. 7 described above, basically, one PSCCH and one PSSCH are transmitted per PSSCH slot and subchannel, and in a specific case, one PSCCH may transmit SCI for two or more PSSCHs. In addition, PSFCH resources corresponding to each PSSCH slot and subchannel may be allocated.

8 is a diagram illustrating another embodiment of a sidelink channel transmission scenario of 5G NR.

Referring to FIG. 8, an example in which PSSCHs for transmitting sidelink data are transmitted through different subchannels similarly to that described in FIG. 7 and PSFCHs for HARQ feedback are transmitted is illustrated. In addition, PSSCHs that transmit a part (first stage) of SCI necessary for receiving PSSCHs are illustrated together.

In the embodiment of FIG. 8 , the interval between the PSCCH/PSSCH and the corresponding PSFCH may be a minimum of 2 slots and a maximum of 3 slots in consideration of the time required for PSSCH demodulation. Specifically, for example, HARQ feedback associated with PSSCH #06 and PSCCH #06 may be transmitted through PSFCH #06 as shown by reference numeral 801. In this case, the interval between PSCCH/PSSCH and PSFCH may be 2 slots. As another example, HARQ feedback associated with PSSCH #03 and PSCCH #03 may be transmitted through PSFCH #03 as shown by reference numeral 802. In this case, the interval between PSCCH/PSSCH and PSFCH may be 3 slots.

If the PSFCH period is shortened as illustrated in FIG. 8, the effect of reducing the delay for sidelink communication can be obtained, which can be more effectively used for low-latency services such as V2X.

Since the specific configuration of FIG. 8 can be understood using the information described in FIG. 7, detailed additional description will be omitted.

Meanwhile, in sidelink transmission, HARQ feedback for transmitting PSCCH and PSSCH reception results may be set differently according to communication modes. Hereinafter, sidelink HARQ feedback defined in the 5G NR standard will be briefly described.

First of all, in the unicast communication mode, the receiving terminal may perform one of the following three operations.

1) When the receiving terminal successfully receives the PSCCH and successfully receives the PSSCH including user data and additional control information by utilizing this control information, the receiving terminal may transmit "ACK" to the transmitting terminal.

2) When the receiving terminal successfully receives the PSCCH but does not successfully receive the PSSCH including user data and additional control information, the receiving terminal may transmit "NACK" to the transmitting terminal.

3) If the receiving terminal does not successfully receive the PSCCH, the receiving terminal does not transmit any signal to the transmitting terminal ("No Signal").

The three cases described above can be interpreted as indicating the state of the received power level as follows.

For example, when the receiving terminal transmits “ACK” through the PSFCH, it may mean that transmission power of a currently configured sidelink between the receiving terminal and the transmitting terminal is sufficient to receive the PSCCH and the PSSCH.

As another example, when the receiving terminal transmits "NACK" through the PSFCH, it may mean that the currently configured sidelink transmission power between the receiving terminal and the transmitting terminal is sufficient for PSCCH reception, but somewhat insufficient for receiving the PSSCH.

As another example, if the receiving terminal does not transmit any signal through the PSFCH, it may mean that transmission power of a currently set sidelink between the receiving terminal and the transmitting terminal is insufficient to receive the PSCCH and the PSSCH.

Meanwhile, in the 5G NR standard, two options are adopted as sidelink HARQ feedback methods in groupcast communication mode.

The first option is a NACK-based feedback method, and the receiving terminal successfully receives the PSCCH but does not successfully receive the PSSCH, and the relative distance between the receiving terminal and the transmitting terminal is within the required communication range. "NACK" is transmitted to the transmitting terminal, and signals are not transmitted in the other cases ("No Signal").

In the second option, the same procedure as the sidelink HARQ feedback procedure in unicast communication mode is used.

In the first option, since the PSFCH channel is shared and used by terminals belonging to groupcast, PSFCH resource efficiency is increased, but the reliability of sidelink groupcast communication may be somewhat insufficient.

In the second option, since resource efficiency of the PSFCH channel is separately allocated to terminals belonging to the groupcast, resource efficiency is lowered, but reliability of sidelink groupcast communication can be increased through retransmission to a specific terminal.

As described above, in 5G NR sidelink communication, in order to provide direct communication between terminals, synchronization setting between terminals, open loop power control between terminals, and HARQ operation between terminals are performed, resulting in relatively reliable reliability compared to communication between the base station and the terminal. this may fall Typically, when sidelink communication is performed through open-loop power control, an error may occur when measuring downlink path loss and sidelink path loss for open-loop power control. Such an error may cause excessive transmission power. Since excessive transmit power can cause a problem that greatly affects uplink communication quality, in order to solve this problem, a sufficient negative power offset is applied to the transmit power estimated by open loop power control to obtain a transmit power smaller than the estimated transmit power. should be sent to

For example, even in the random access method using open-loop power control, in order to prevent such an excessive transmission power problem, for example, transmission of -12dB to -9dB that is sufficiently smaller than the power estimated through open-loop power control It is set to transmit with power.

Therefore, as described above, when direct communication is performed between terminals using the sidelink channels (PSCCH and PSSCH) to which open-loop power control is applied, the probability of successful reception decreases, which causes unnecessary PSSCH (re)transmission. will do Accordingly, when a method in which a PSCCH and a corresponding PSSCH are simultaneously transmitted in one slot is used in a 5G NR sidelink scenario, the PSSCH is transmitted even in a situation where PSCCH reception is not successful due to an error in open loop power control. The power consumption of is increased, and unnecessary interference is caused to degrade uplink communication quality.

Therefore, in 5G NR sidelink communication, resource consumption and terminal power consumption that may occur by transmitting the PSCCH and the corresponding PSSCH in the same slot using the open loop power control method as described above, and increase the effect of uplink reception interference There is a need for a method and apparatus for solving such problems. In addition, in 5G NR sidelink communication, it is necessary to improve the PSCCH and PSSCH transmission schemes to provide stable sidelink communication.

In the following description, a method and apparatus including a technology for securing sidelink communication performance will be described.

9 is a flowchart illustrating an operation between a transmitting terminal and a receiving terminal during sidelink control channel transmission power ramping according to the present disclosure.

The transmitting terminal 210 may be a terminal that transmits user data, signaling and/or control signals in sidelink communication, and the receiving terminal 220 receives user data, signaling and/or control signals in sidelink communication. can be a terminal. For example, during sidelink communication in unicast mode, terminals transmitting data, signaling, and/or control signals may be switched between each other. As another example, during sidelink communication in the group cast mode, a terminal that transmits user data to a plurality of terminals in a group may be a transmitting terminal 210, and terminals that receive user data from a specific terminal may be a receiving terminal ( 220) can be.

In the following description, the operation of FIG. 9 will be described with respect to a method of determining transmit power during sidelink communication in unicast mode.

In step S211, the transmitting terminal 210 may determine transmit power of a control channel to be transmitted using an open loop power control method. Since the open loop power control method is a widely known technique in the field of mobile communication, a detailed description thereof will be omitted.

In step S212, the transmitting terminal 210 may transmit the PSCCH with power determined based on the open loop power control method. In FIG. 9, only transmission of the PSCCH is illustrated, but as in FIGS. 7 and 8 described above, the PSCCH may be transmitted together with the PSSCH. However, in the embodiment of FIG. 9 according to the present disclosure, only the PSCCH may be transmitted.

In step S212, the receiving terminal 220 may attempt reception detection of the "control channel" or "control channel and data channel". In FIG. 9 according to an embodiment of the present disclosure, the transmitting terminal 210 transmits only the PSCCH. Therefore, the receiving terminal 210 cannot detect the data channel in step S212, and can demodulate and decode the received control channel, for example, the PSCCH.

In step S213, the receiving terminal 210 may determine HARQ feedback based on the demodulation and decoding results of the control channel. If the transmitting terminal 210 transmits both the control channel and the data channel, the receiving terminal 220 may operate according to one of the three operations of the receiving terminal in the unicast communication mode described above with reference to FIG. 8 when determining HARQ feedback. there is.

For example, the receiving terminal 220 may transmit "ACK" when demodulation and decoding of control information transmitted through a control channel and user data transmitted through a data channel are successful.

As another example, when the receiving terminal 220 successfully demodulates and decodes the control information transmitted through the control channel, but fails to demodulate and decode the user data transmitted through the data channel, the receiving terminal 220 may transmit "NACK". there is.

As another example, the receiving terminal 220 may not transmit any signal when demodulation and decoding of both control information transmitted through the control channel and user data transmitted through the data channel fail. In this case, no signal is transmitted because it cannot be identified whether the actual transmitting terminal 210 has transmitted a signal. ACK and NACK can be transmitted through a promised resource like the PSFCH described above with reference to FIGS. 7 and 8 .

In FIG. 9 according to the present disclosure, it is assumed that only the PSCCH is transmitted. Therefore, this is a case where there is no data transmitted through the PSSCH. Therefore, the receiving terminal 220 fails even if it attempts demodulation and decoding because there is no data transmitted on the PSSCH. Therefore, as shown in FIG. 9, when the transmitting terminal 210 transmits only the PSCCH, the receiving terminal 220 cannot feed back an ACK.

In step S214, the receiving terminal 220 may transmit HARQ feedback through a promised resource such as PSFCH. In step S214, the HARQ feedback that the receiving terminal 220 can transmit may be NACK or no signal.

In step S214, the transmitting terminal 210 may receive feedback from the receiving terminal 220. In general, the transmitting terminal 210 may receive ACK, NACK, or may not receive any signal (No Signal). However, in the case of FIG. 9, the transmitting terminal may receive a NACK or may not receive any signal (No Signal).

In step S215, the transmitting terminal 210 may determine transmission power based on the HARQ feedback received in step S214. The transmitting terminal 210 may determine the transmission power according to which signal is received from the receiving terminal 220 when determining the transmission power. The transmitting terminal 210 may identify whether or not the receiving terminal 220 has successfully demodulated and decoded the control channel based on the signal received in step S214. Depending on the success of demodulation and decoding of the control channel, the receiving terminal 220 transmits "NACK" or does not transmit any signal (No Signal). Therefore, the fact that the transmitting terminal 210 has received "NACK" means that the receiving terminal 220 successfully received the control channel, but failed to receive (or demodulate and decode) the data channel. In addition, the fact that the transmitting terminal 210 did not receive any signal (No Signal) indicates that the receiving terminal 220 did not successfully receive the control channel.

The transmitting terminal 210 may determine transmission power of PSCCH or transmission power of PSCCH/PSSCH based on the received signal in step S215. Determination of transmission power of PSCCH or transmission power of PSCCH/PSSCH may be performed as follows.

When a “NACK” signal is detected in HARQ feedback, the transmitting terminal 210 according to the present disclosure may determine power of PSCCH/PSSCH. On the other hand, when no signal is transmitted through HARQ feedback, the transmitting terminal 210 according to the present disclosure may re-determine only transmission power of the PSCCH.

Specifically, when the "NACK" signal is detected in the HARQ feedback, the transmitting terminal 210 knows that the transmission power set to transmit the PSCCH in step S212 is sufficient for receiving terminal 220 to receive and demodulate and decode the PSCCH. can Therefore, in step S215, the transmitting terminal 210 may determine the transmit power of the PSCCH as the transmit power of the PSCCH previously set in step S212. In addition, the transmitting terminal 210 may determine transmission power of the PSSCH to be transmitted in step S216 based on the transmission power of the PSCCH determined in step S215. The transmit power of the PSSCH may be equal to or higher than the transmit power of the PSCCH.

On the other hand, when no signal is received in the symbol promised by HARQ feedback, the transmitting terminal 210 determines that the transmission power set to transmit the PSCCH in step S212 is insufficient for receiving terminal 220 to demodulate and decode. Able to know. Accordingly, the transmission terminal 210 according to the present disclosure may set the transmit power of the PSCCH to a new value in step S215. For example, the transmission power of the PSCCH determined in step S215 may be set to a higher value than the power value set in step S211. At this time, the power value higher than the power value set in step S211 may be a value obtained by adding a specific power value set in advance to the power value set in step S211.

In step S216, the transmitting terminal 210 may transmit only the PSCCH or transmit the PSCCH/PSSCH together based on the power determination in step S215. If the transmitting terminal 210 transmits only the PSCCH, it is a case where no signal is received from the HARQ feedback resource in step S214, and if the transmitting terminal 210 transmits the PSCCH/PSSCH, it receives NACK from the HARQ feedback resource. may be the case

Using the method illustrated in FIG. 9 , before actual data transmission between the transmitting terminal 210 and the receiving terminal 220 , it is possible to accurately know the power required for data transmission using HARQ feedback. Accordingly, unnecessary power waste of the transmitting terminal 210 caused by PSSCH transmission failure can be prevented. In addition, interference of the PSSCH, which fails to transmit from the transmitting terminal 210 to the receiving terminal 220, on sidelink communication of other terminals or uplink communication of the base station can be reduced.

10A is an exemplary view of a part for explaining channel transmission power ramping when a transmitting terminal transmits a sidelink control channel according to an embodiment of the present disclosure, and FIG. 10B is a diagram continuing from FIG. 10A according to an embodiment of the present disclosure. It is an exemplary diagram for explaining channel power ramping when a transmitting terminal transmits a sidelink control channel.

Hereinafter, an operation of a transmitting terminal using transmit power ramping of a control channel in a unicast mode sidelink according to the present disclosure will be described using FIGS. 10A and 10B.

Referring to FIG. 10A , the transmission terminal 210 previously described in FIG. 9 may transmit a control channel, for example, a PSCCH 230 through an allocated resource. At this time, the transmission power of the first control channel 230 may be the transmission power (P ₀ ) determined by the open loop power control method as in step S211 described with reference to FIG. 9 .

The transmitting terminal 210 may then attempt signal detection in a predetermined HARQ feedback resource as in step S214 described with reference to FIG. 9 . 10a illustrates a “No Signal” state in which no signal is detected in HARQ feedback resources. When the signal is not detected in the HARQ feedback resource, the transmitting terminal 210 may transmit the second control channel 231 in the next resource. In this case, the second control channel 231 may transmit with transmission power increased by a preset power increment ΔP to the transmission power used for the first control channel 230 . In FIG. 10A , power increased by a preset power increase amount (ΔP) to the transmission power (P ₀ ) determined by the open-loop power control method is exemplified as P ₁ .

After transmitting the second control channel 231, the transmitting terminal 210 may attempt to detect a signal in a corresponding HARQ feedback resource. 10A illustrates a case in which there is no HARQ feedback signal even after transmission of the second control channel 231.

When the transmission terminal 210 determines that the feedback signal for the second control channel 231 is also “No Signal,” the transmission power reflected in the second control channel 231 is increased by a preset power increment ΔP. The third control channel 232 may be transmitted again at the next control channel transmission time point with the power P ₂ .

10A illustrates a case in which the receiving terminal 220 transmits the HARQ feedback signal 233 through a predetermined resource, for example, the PSFCH after transmitting the third control channel 232. Accordingly, the transmitting terminal 210 may receive the NACK as HARQ feedback as in step S214 described with reference to FIG. 9 .

FIG. 10B is an exemplary diagram for explaining timing subsequent to FIG. 10A. Accordingly, in FIG. 10B , the horizontal axis means time, and the vertical axis means power. However, the power of the vertical axis is different in that the scale is different from that of FIG. 10A. Also, in FIG. 10A, the timing at which the receiving terminal 220 transmits the NACK corresponds to the end of the timing diagram. In FIG. 10B, the timing at which the receiving terminal 220 transmits the NACK corresponds to the start of the timing diagram. That is, the timing at which NACK is transmitted to the HARQ feedback signal 233 in FIG. 10A and the timing at which NACK is transmitted to the HARQ feedback signal 233 in FIG. 10B may correspond to each other.

Referring to FIG. 10B, the transmitting terminal 210 may detect that NACK is transmitted as an HARQ feedback signal 233. As described in FIG. 10A, the transmitting terminal 210 is in a state of transmitting only the first control channel 230, the second control channel 231, and the third control channel 232. Therefore, the transmitting terminal 210 can only receive the HARQ feedback signal 233 NACK or receive no signal.

Accordingly, the fact that the transmitting terminal 210 has received the NACK indicates that the transmission power of the third control channel 232 is an appropriate power that the receiving terminal 220 can detect. Accordingly, the transmitting terminal 210 may transmit the fourth control channel 234 and the first data channel 235 to the reserved resource at the next time point. In this case, the fourth control channel 234 may be determined based on the transmit power of the third control channel 232 . For example, the fourth control channel 234 may be determined to have the same power (P ₂ ) as the power of the third control channel 232 described above. Also, the transmitting terminal 210 may determine the first data channel 235 based on the transmission power of the third control channel 232 . In FIG. 10B , the transmission power of the first data channel is illustrated as P ₃ .

The transmitting terminal 210 transmits the fourth control channel 234 and the first data channel (234) and the first data channel (235) using the determined power values (P ₂ and P ₃ ). 235) can be transmitted.

Afterwards, the transmitting terminal 210 may receive the HARQ feedback signal 236 through a predetermined resource. In FIG. 10B, a case in which “NACK” is received as the HARQ feedback signal 236 is illustrated. When NACK is received, the transmitting terminal 210 may recognize that transmission power of the actually transmitted first data channel 235 is not sufficient.

Therefore, the transmitting terminal 210 may determine the transmit power of the second data channel 238 as higher power (P ₄ ) than the transmit power of the first data channel 235 . In addition, the fact that the transmitting terminal 210 has received a NACK means that the receiving terminal 220 has received a control channel and has succeeded in demodulation and decoding. Accordingly, transmission power of the fifth control channel 237 may be determined as the same power (P ₂ ) as that of the previous fourth control channel 234 .

As another method of power determination according to the present disclosure, when determining the transmit power of the second data channel 238, the open loop power control, the transmit power of the fourth control channel 234 and the transmit power of the first data channel 235 It can be determined by considering the power. Therefore, in FIG. 10B, although the power of the second data channel 238 is determined to be higher than the power of the first data channel 235, considering the open loop method, the distance between the receiving terminal 220 and the transmitting terminal 210 becomes smaller or Alternatively, when the propagation environment is improved, it may have a value different from the power illustrated in FIG. 10B. The transmission power of the fifth control channel 237 as well as the power value of the second data channel 238 is the same as that of the power of the second data channel 238, open loop power control, the fourth control channel 234 It can be determined in consideration of transmit power and transmit power of the first data channel 235 .

Since the transmitting terminal 210 receives the NACK through the HARQ feedback resource corresponding to the first data channel 235, the fifth control channel 237 and the second data channel 238 are determined in the next reserved resource. The fifth control channel 237 and the second data channel 238 may be transmitted using the power values P ₂ and P ₄ .

The transmitting terminal 210 may receive the HARQ feedback signal 238 through a predetermined resource in response to transmission of the fifth control channel 237 and the second data channel 238 . In FIG. 10B, the case where ACK is received as the HARQ feedback signal 238 is illustrated. When the ACK is received as the HARQ feedback signal 238, the transmitting terminal 210 may determine the corresponding sidelink data transmission as “successful” and complete the procedure.

Meanwhile, control channels that are not transmitted together with data channels, such as the first control channel 230, the second control channel 231, and the third control channel 232 described above, may be set to include the same control information. .

On the other hand, since the fourth control channel 234 and the fifth control channel 237 are associated with the first data channel 235 and the second data channel 238, respectively, different control information is transmitted according to a change in allocated resources. can In addition, the first data channel 235 and the second data channel 238 are generated based on the same data, and different symbols are selected and transmitted among coded symbols according to the HARQ retransmission procedure for signals used for actual transmission. It can be.

In addition, the number of transmissions of control channels that are not transmitted together with data channels, such as the first control channel 230, the second control channel 231, and the third control channel 232, may be set to a certain number and limited. The transmitting terminal 9210) may not receive the HARQ feedback signal through a predetermined resource as in step S214 described in FIG. 9 even though it has transmitted as many times as the set number of transmissions (No Signal). In this way, when the HARQ feedback signal is not received, the transmitting terminal 210 may determine the corresponding sidelink data transmission as “failure” and complete the procedure. At this time, the set number of transmissions may include “0”. When the set transmission number is “0”, the transmission power determined in the open loop power control step (S211) may be used as the transmission power of the fourth control channel 234 and the first data channel 235.

In addition, the control channel and the data channel, such as the first data channel 235 transmitted together with the fourth control channel 234 or the second data channel 238 transmitted together with the fifth control channel 237, are configured in the same slot. The maximum number of simultaneous transmissions can be set to a certain number. Even though the transmitting terminal 210 has transmitted as many times as the set number of transmissions, when the HARQ feedback signal is "NACK" or "No Signal" through a predetermined resource as in step S214, the corresponding sidelink data transmission is determined to be "failed". and complete the procedure. At this time, the set maximum number of transmissions may include “1” to prevent retransmission.

In addition, an upper limit of transmission power of control channels that are not transmitted together with data channels, such as the first control channel 230, the second control channel 231, and the third control channel 232, may be set. In a situation in which the set number of transmissions is not transmitted, if the upper limit of the set transmission power is exceeded, the transmitting terminal 210 continues to transmit the control channel with the transmission power corresponding to the upper limit value, or the sidelink data transmission is "failed". ", and the procedure can be completed.

11 is an exemplary diagram for explaining resource use in a sidelink channel transmission scenario according to an embodiment of the present disclosure.

Prior to referring to FIG. 11, comparing with FIG. 7, it can be seen that they have the same shape. That is, in FIG. 11, as in FIG. 7, the number (N) of PSSCH slots associated with one PSFCH symbol is 4 and the number (L) of subchannels allocated to the sidelink is 3, and the PSFCH period ( N) is a unit of 4 slots, and a PSSCH slot minimum offset (K) associated with one PSFCH symbol can be a sidelink channel transmission scenario of 5G NR using a parameter of 2.

Therefore, in FIG. 11, the same reference numerals as in FIG. 7 described above will be used for each resource, for example, PSSCHs, PSCCHs, and PSFCHs.

In FIG. 11, a transmission method according to the present disclosure that is different from that of FIG. 7 described above will be described, and will be described in contrast to FIG. 7 described above.

In the sidelink channel transmission scenario according to the embodiment of FIG. 7 described above, both the sidelink control channel and the sidelink data channel are transmitted in all resources (slots, subchannels, etc.). On the other hand, in the sidelink channel transmission scenario illustrated in FIG. 11 according to the present disclosure, there is a difference in that both the sidelink control channel and the sidelink data channel are transmitted only in some resources, and only the sidelink control channel is transmitted in the remaining resources. That is, as described above with reference to FIG. 9, before transmitting the data channel of the sidelink, the sidelink transmitting terminals transmit only the control channel so that appropriate transmission power can be known.

Due to this difference, in the sidelink channel transmission scenario according to the present disclosure, power consumption of terminals is relatively reduced and the effect of interference on the uplink is reduced.

In the unicast mode sidelink providing direct communication between terminals according to the present disclosure, the sidelink channel transmission scenario based on transmission power ramping of the control channel uses the HARQ feedback method for the data channel as it is proposed in 5G NR technology. there is.

As another example, in a unicast mode sidelink providing direct communication between devices according to the present disclosure, a sidelink channel transmission scenario based on transmission power ramping of a control channel may change an HARQ feedback method for a data channel. By changing the HARQ feedback method for the data channel according to the present disclosure, a new HARQ feedback method for a data channel that can more effectively realize a low-delay factor will be reviewed with reference to FIG. 11 .

In the unicast mode sidelink channel transmission scenario according to the present disclosure, feedback for a control channel may be additionally adopted. For example, by newly defining a control channel feedback signal whether reception of a control channel is successful or not, it is possible to distinguish a feedback signal of a data channel from a feedback signal of a data channel. By feeding back a feedback signal for a control channel having a short reception processing time more quickly, it is possible to obtain a benefit of reducing a sidelink channel transmission delay factor by realizing faster ramping of transmission power of the control channel.

A method for distinguishing between control channel and data channel feedback signals according to the present disclosure will be described.

When a feedback signal is transmitted according to the method proposed as a standard in 5G NR for the sidelink channel transmission method illustrated in FIGS. 7 and 11, a time delay of at least 2 slots and up to 5 slots occurs at the feedback transmission point.

More specifically, referring to FIG. 7, PSSCH #12 (120-12) and PSCCH #12 (110-12) may be fed back through resources of PSFCH #12 (130-12) two slots later. That is, a delay of 2 slots occurs.

PSSCH #09 (120-09) and PSCCH #09 (110-09), which are the first slots transmitted using the same PSFCH resource, can be fed back through the resources of PSFCH #09 (130-09) 5 slots later. Therefore, when using the NR standard method, a delay of a minimum of 2 slots and a maximum of 5 slots may occur in feedback.

In contrast, in the present disclosure, the delay of the feedback signal of the control channel may be reduced to a minimum of 0 slots and a maximum of 3 slots. Specifically, for example, in the case of PSCCH #10 (110-10), according to the NR standard, feedback must be made through PSFCH #10 (130-10) together with corresponding PSSCH #10 (120-10). However, in the present disclosure, as shown by reference numeral 1101, feedback on the control channel of PSCCH #10 (110-10) may be transmitted through PSFCH #10 (120-10). By newly defining a feedback signal for a control channel, each PSFCH resource can be allocated and used as a feedback signal for a data channel and a control channel.

However, even in the present disclosure, the NR standard may be used as feedback for the data channel. For example, feedback on PSSCH #12 (120-12) in FIG. 11 can be transmitted through PSFCH #12 (130-12) as shown by reference numeral 1102, and feedback on PSSCH #09 (120-09) is referenced. As shown in code 1103, it can be transmitted through PSFCH #09 (130-09).

In summary, in the NR standard, a delay occurs by the number of slots based on the number of PSSCH slots associated with a PSFCH symbol among slots transmitted at least 2 slots before the feedback resource. Accordingly, the delay of the PSCCH associated with the PSSCH also has the same delay. On the other hand, according to the present disclosure, all PSCCHs included in a PSFCH period can be directly fed back through a PSFCH symbol. Therefore, the delay time can be minimized when using the method according to the present disclosure.

12A is an exemplary view of a portion for explaining channel transmission power ramping when a transmitting terminal transmits a sidelink control channel according to an embodiment of the present disclosure, and FIG. 12B is a diagram continuing from FIG. 12A according to an embodiment of the present disclosure. It is an exemplary diagram for explaining channel power ramping when a transmitting terminal transmits a sidelink control channel.

The scenarios of FIGS. 12A and 12B apply the method of distinguishing the feedback signals of the control channel and the data channel described above.

In FIG. 12A , a horizontal axis may mean time, and a vertical axis may mean power. Then, referring to FIG. 12A, a method for determining sidelink transmission power by a transmitting terminal according to the present disclosure will be described. In addition, in FIGS. 12a and 12b according to the present disclosure, the feedback of the control channel may be a case of using an ACK-based feedback of an "ACK-No" scheme instead of an "ACK-NACK" scheme.

Referring to FIG. 12A , a transmitting terminal 210 may transmit a first control channel 204, for example, a PSCCH, to a receiving terminal 220 through an allocated resource. In this case, the transmit power of the first control channel 240 may be the transmit power P ₀ determined by the open loop power control method. Thereafter, the transmitting terminal 210 may attempt signal detection in a predefined HARQ feedback resource. In FIG. 12a, a “No Signal” state in which no signal is detected in HARQ feedback resources is illustrated. When the signal is not detected in the HARQ feedback resource, the transmitting terminal 210 may transmit the second control channel 241 in the next resource. In this case, the second control channel 241 may transmit with transmission power increased by a preset power increment ΔP to the transmission power used for the first control channel 240 . In FIG. 12A , power increased by a preset power increase amount (ΔP) to the transmission power (P ₀ ) determined by the open-loop power control method is exemplified as P ₁ . After transmitting the second control channel 241, the transmitting terminal 210 may attempt to detect a signal in a corresponding HARQ feedback resource. 12a illustrates a case in which there is no HARQ feedback signal even after transmission of the second control channel 241. When the transmission terminal 210 determines that the feedback signal for the second control channel 241 is also “No Signal”, the transmission power reflected in the second control channel 241 is increased by a preset power increment ΔP. The third control channel 242 may be transmitted again at the next control channel transmission time with the power (P ₂ ).

The above description may be the same operation as that of FIG. 10A.

12a illustrates a case in which the receiving terminal 220 having received the third control channel 242 transmits the HARQ feedback signal 243 through a predetermined resource, for example, the PSFCH. The case of FIG. 10 is a method using the “ACK-NACK” scheme, but FIG. 12A is based on the “ACK-No” scheme, and as described above, the control channel and the data channel are separated and fed back. Accordingly, when the receiving terminal 220 receives the third control channel 242 and successfully demodulates and decodes, an ACK may be transmitted as the HARQ feedback signal 243.

FIG. 12B is an exemplary diagram for explaining timing subsequent to FIG. 12A. Accordingly, in FIG. 12B, the horizontal axis means time, and the vertical axis means power. However, the power of the vertical axis is different in that the scale is different from that of FIG. 12A. Also, in FIG. 12A, the timing at which the receiving terminal 220 transmits the ACK corresponds to the end of the timing diagram. In FIG. 12B, the timing at which the receiving terminal 220 transmits the ACK corresponds to the start of the timing diagram. That is, the timing at which the ACK is transmitted through the HARQ feedback signal 243 in FIG. 12A may correspond to the timing at which the ACK is transmitted through the HARQ feedback signal 243 in FIG. 12B.

Referring to FIG. 12B, the transmitting terminal 210 may detect that the ACK is transmitted as the HARQ feedback signal 243. The fact that the transmitting terminal 210 has received the ACK indicates that the transmission power of the third control channel 242 is an appropriate power capable of being detected by the receiving terminal 220 . Accordingly, the transmitting terminal 210 may transmit the fourth control channel 244 and the first data channel 245 to the reserved resource at the next time point. In this case, the fourth control channel 244 may be determined based on the transmit power of the third control channel 242 . For example, the fourth control channel 244 may be determined to have the same power (P ₂ ) as that of the third control channel 242 described above. Also, the transmitting terminal 210 may determine the first data channel 245 based on the transmission power of the third control channel 242 . In FIG. 12B, the transmission power of the first data channel 255 is illustrated as P ₃ .

The transmitting terminal 210 transmits the fourth control channel 244 and the first data channel (244) and the first data channel (245) using the determined power values (P ₂ and P ₃ ). 245) can be transmitted.

Then, the transmitting terminal 210 may receive the HARQ feedback signal through a predetermined resource. At this time, in the embodiments of FIGS. 12A and 12B according to the present disclosure, it is assumed that HARQ feedback of a control channel and a data channel are separated and transmitted. Therefore, feedback for each of the fourth control channel 244 and the first data channel 245 can be made.

Referring to FIG. 12B, the signal of the control channel feedback 246-1 for the fourth control channel 244 is fed back as “ACK”, and the data channel feedback 246-2 for the first data channel 245 Illustrates the case of being fed back with NACK. Accordingly, the transmission terminal 210 may determine the transmission power of the fifth control channel 247 as the same power (P ₂ ) as that of the previous fourth control channel 244 . Also, the transmitting terminal 210 may determine the transmit power of the second data channel 248 as higher than the transmit power of the first data channel 245 (P ₄ ).

As another method of determining the transmit power of the second data channel 248, open-loop power control when determining the transmit power of the second data channel 248 as described above with reference to FIG. 10B, transmit power of the fourth control channel 244 And it may be determined considering the transmit power of the first data channel 245.

Thereafter, the transmitting terminal 210 receives "ACK" as the feedback 249-1 for the control channel in the HARQ feedback reception step S214 as shown in FIG. 9 described above, and the feedback 249-2 for the data channel If "ACK" is received with , sidelink data transmission may be determined as "successful" and the procedure may be completed.

In the above procedure, the first control channel 240, the second control channel 241, and the third control channel 242 transmitted in FIG. 12A are the first control channel 230 transmitted in FIG. 10A, the second control channel ( 231) and the third control channel 232 can be viewed as the same procedure, but if the method described in FIG. 11 is used, feedback of the control channel can be received more quickly. Therefore, the time interval between each control channel is significantly reduced.

In addition, as described with reference to FIG. 9, since the data channel is transmitted only when reception of the control channel is successful, interference can be reduced.

13A is an exemplary view of a part for explaining channel transmission power ramping when a transmitting terminal transmits a sidelink control channel according to an embodiment of the present disclosure, and FIG. 13B is a diagram continuing from FIG. 13A according to an embodiment of the present disclosure. It is an exemplary diagram for explaining channel power ramping when a transmitting terminal transmits a sidelink control channel.

The scenarios of FIGS. 13A and 13B apply the method of distinguishing the feedback signals of the control channel and the data channel described above.

In FIG. 13A , a horizontal axis may mean time, and a vertical axis may mean power. Then, referring to FIG. 13A, a method for determining sidelink transmission power by a transmitting terminal according to the present disclosure will be described. In addition, in FIGS. 13a and 13b according to the present disclosure, the feedback of the control channel will be the case of using the ACK-based feedback of the "ACK-No" system instead of the "ACK-NACK" system as in the previously described FIGS. 12a and 12b. can In addition, in FIGS. 13A and 13B, the feedback signal of the data channel may also be a case of using an ACK-based feedback, which is an "ACK-No" scheme instead of an "ACK-NACK" scheme. That is, when the data channel is successfully received, the “ACK” signal is fed back, and when the data channel is not successfully received, no signal is fed back (No Signal).

Referring to FIG. 13A , a transmitting terminal 210 may transmit a first control channel 250, for example, a PSCCH, to a receiving terminal 220 through an allocated resource. At this time, the transmission power of the first control channel 250 may be the transmission power (P ₀ ) determined by the open loop power control method. Thereafter, the transmitting terminal 210 may attempt signal detection in a predefined HARQ feedback resource. 13a illustrates a “No Signal” state in which no signal is detected in HARQ feedback resources. When the signal is not detected in the HARQ feedback resource, the transmitting terminal 210 may transmit the second control channel 251 in the next resource. In this case, the second control channel 251 may transmit with transmission power increased by a preset power increment ΔP to the transmission power used for the first control channel 250 . In FIG. 13A , the power increased by a preset power increment ΔP to the transmission power P ₀ determined by the open-loop power control method is exemplified as P ₁ . After transmitting the second control channel 251, the transmitting terminal 210 may attempt to detect a signal in a corresponding HARQ feedback resource. 13A illustrates a case in which there is no HARQ feedback signal even after transmission of the second control channel 251. When the transmission terminal 210 determines that the feedback signal for the second control channel 251 is “No Signal,” the transmission power reflected in the second control channel 251 is increased by a preset power increment ΔP. With the power P ₂ , the third control channel 252 may be transmitted again at the time of transmission of the next control channel.

13A illustrates a case in which the receiving terminal 220 having received the third control channel 252 transmits the HARQ feedback signal 253 through a predetermined resource, for example, the PSFCH. 12a is based on the “ACK-No” scheme and, as described above, is a case in which the control channel and the data channel are separated and fed back. Accordingly, when the receiving terminal 220 receives the third control channel 252 and successfully demodulates and decodes, an ACK may be transmitted as the HARQ feedback signal 253.

The above description may be the same procedure as that of FIG. 12A described above.

FIG. 13B is an exemplary diagram for explaining timing subsequent to FIG. 13A. Accordingly, in FIG. 13B, the horizontal axis means time, and the vertical axis means power. However, the power of the vertical axis is different in that the scale is different from that of FIG. 13A. Also, in FIG. 13A, the timing at which the receiving terminal 220 transmits the ACK corresponds to the end of the timing diagram. In FIG. 13B, the timing at which the receiving terminal 220 transmits the ACK corresponds to the start of the timing diagram. That is, the timing at which the ACK is transmitted through the HARQ feedback signal 253 in FIG. 13A may correspond to the timing at which the ACK is transmitted through the HARQ feedback signal 253 in FIG. 13B.

Referring to FIG. 13B, the transmitting terminal 210 may detect that an ACK is transmitted as an HARQ feedback signal 253. The fact that the transmitting terminal 210 has received the ACK indicates that the transmission power of the third control channel 252 is an appropriate power that can be detected by the receiving terminal 220 . Accordingly, the transmitting terminal 210 may transmit the fourth control channel 254 and the first data channel 255 to the reserved resource at the next time point. In this case, the fourth control channel 254 may be determined based on the transmit power of the third control channel 252 . For example, the fourth control channel 254 may be determined to have the same power (P ₂ ) as that of the third control channel 252 described above. Also, the transmitting terminal 210 may determine the first data channel 255 based on the transmission power of the third control channel 252 . In FIG. 13B, the transmission power of the first data channel 255 is illustrated as P ₃ .

The transmitting terminal 210 transmits the fourth control channel 254 and the first data channel (254) using the determined power values (P ₂ and P ₃ ) for the fourth control channel 254 and the first data channel (255). 255) can be transmitted.

Then, the transmitting terminal 210 may receive the HARQ feedback signal through a predetermined resource. At this time, in the embodiments of FIGS. 13A and 13B according to the present disclosure, it is assumed that HARQ feedback of a control channel and a data channel are separated and transmitted. Therefore, feedback for each of the fourth control channel 254 and the first data channel 255 can be made. In addition, in FIGS. 13A and 13B , an ACK-based feedback, which is an “ACK-No” system, is used not only in the control channel but also in the data channel.

Referring to FIG. 13B, the signal of the control channel feedback 256-1 for the fourth control channel 254 is fed back as “ACK”, and the data channel feedback 246-2 for the first data channel 255 exemplifies a case in which no signal is transmitted as "No Signal". Accordingly, the transmitting terminal 210 may determine that transmission of the fourth control channel 254 has succeeded, but transmission of the first data channel 255 has failed. Accordingly, the transmitting terminal 210 may determine the transmission power of the fifth control channel 257 as the same power (P ₂ ) as that of the previous fourth control channel 254 . Also, the transmitting terminal 210 may determine the transmit power of the second data channel 258 as higher than the transmit power of the first data channel 255 (P ₄ ).

As another method of determining the transmit power of the second data channel 258, when determining the transmit power of the second data channel 258, open-loop power control, the transmit power of the fourth control channel 254 and the first data channel It may be determined by considering the transmit power of (255).

Thereafter, as shown in FIG. 9 described above, the transmitting terminal 210 receives "ACK" as the feedback 249-1 for the control channel in the HARQ feedback reception step S214, and the feedback 249-2 for the data channel. ), sidelink data transmission may be determined as “successful” and the procedure may be completed.

In the above procedure, the first control channel 240, the second control channel 241, and the third control channel 242 transmitted in FIG. 13A are the first control channel 240 transmitted in FIG. 12A, the second control channel ( 241) and the third control channel 242 may be transmitted by the same procedure. Accordingly, the same effect as described in FIGS. 12A and 12B may be obtained.

Since the method according to FIGS. 13A and 13B uses ACK-based feedback even in the data channel, fewer signals are transmitted for feedback than in FIGS. 12A and 12B. Therefore, there is an advantage in that power consumption of the terminal can be reduced and the effect of uplink interference can be reduced.

Control channel (PSCCH) transmission power ramping in the sidelink unicast communication mode according to the present disclosure described above can also be applied in the groupcast communication mode. Hereinafter, control channel transmission power ramping in the groupcast communication mode according to the present disclosure will be described.

14 is an exemplary diagram for explaining a case in which one transmitting terminal and three receiving terminals exist in a groupcast communication mode according to an embodiment of the present disclosure.

The example of FIG. 14 is an example of a case in which all receiving terminals transmit HARQ feedback as sidelink feedback option 2 (Option-2) in groupcast communication. In addition, FIG. 14 illustrates a control channel transmission power ramping operation to which ACK-based feedback according to the present disclosure is applied. Here, N _C is the number of receiving terminals transmitting the control channel ACK feedback, N _D is the number of receiving terminals transmitting the data channel ACK feedback, and K is the accumulated number of terminals that successfully receive the data channel.

First, in the first slot, the transmitting terminal transmits only the control channel, and all receiving terminals do not successfully receive the control channel (N _C =0, N _D =0, K=0). Subsequently, at the time of the second slot, receiving terminal #0 successfully receives the control channel and feeds back ACK, and the remaining receiving terminals do not successfully receive the control channel (N _C =1, N _D =0, K= 0).

Due to the ACK fed back by the receiving terminal #0, the transmitting terminal transmits not only the control channel but also the data channel at the time of the third slot. At this third slot, receiving terminal #1 successfully receives the control channel and data channel and feeds back ACK signals, respectively, and receiving terminal #0 successfully receives only the control channel and feeds back the ACK for the control channel. Meanwhile, receiving terminal #2 is in a situation where it has not successfully received any channel (N _C =2, N _D =1, K=1). Here, since the difference between the number of receiving terminals transmitting control channel ACK feedback (N _C ) and the number of receiving terminals transmitting data channel ACK feedback (N _D ) ((N _C - N _D ) is "1", the transmitting terminal is Even at the time of the fourth slot, not only the control channel but also the data channel are transmitted.

At the time of the fourth slot, receiving terminal #0 successfully receives the control channel and data channel and feeds back ACK signals, respectively, and receiving terminal #2 successfully receives only the control channel and feeds back the ACK for the control channel. On the other hand, the transmitting terminal does not take a separate action for the feedback transmitted by the receiving terminal #1, which has already successfully received data, as being redundant (N/A) (N _C =2, N _D =1). , K=2).

Finally, since N _C - N _D = 1 even at the time of the fifth slot, the transmitting terminal transmits not only the control channel but also the data channel, and the receiving terminal #2 successfully receives the control channel and the data channel at the time of the fifth slot, Each may be a case of feeding back an ACK signal. In this way, when all receiving terminals belonging to the groupcast group successfully receive data, the corresponding sidelink data transmission procedure may be completed (N _C =1, N _D =1, K=3).

15 is an exemplary view for explaining a case in which one transmitting terminal and three receiving terminals exist in a groupcast communication mode according to another embodiment of the present disclosure.

15 will also be described using the same parameters as those of FIG. 14 described above. Specifically, FIG. 15 is an example of a case in which all receiving terminals transmit HARQ feedback as sidelink feedback option 2 (Option-2) in groupcast communication. 15, N _C is the number of receiving terminals transmitting control channel ACK feedback, N _D is the number of receiving terminals transmitting data channel ACK feedback, and K is the accumulated number of terminals that successfully receive data channels.

Looking at FIGS. 14 and 15 in contrast, the first and second slot views are the same as the operation of FIG. 14 described above. However, FIG. 15 illustrates a state in which the receiving terminal #0 successfully receives the control channel and the data channel at the time of the third slot and feeds back an ACK signal, and all other receiving terminals fail to successfully receive the control channel. (N _C =1, N _D =1, K=1). Therefore, the feedback by receiving terminal #0 is excluded from the subsequent procedure, and since all of the remaining receiving terminals have not received the control channel (N _C - N _D =0, K≠3), the transmitting terminal is at the time of the fourth slot. Again, only the control channel is transmitted.

Then, since the receiving terminal #2 succeeds in receiving the control channel in the fourth slot, the transmitting terminal can transmit both the control channel and the data channel in the fifth slot. Accordingly, as a response of the fifth slot, both the control channel and the data channel from receiving terminal #1 succeed and feed back ACK signals, respectively, and receiving terminal #2 succeeds in the control channel and can feed back ACK only for the control channel (N _C =2, N _D =1, K=2).

Since the difference ((N _C - N _D ) of the number of receiving terminals (N _D ) transmitting the data channel ACK feedback according to the feedback of the fifth slot is "1", the transmitting terminal transmits the control channel and the data channel together in the sixth slot. In response to the transmission in the sixth slot, it may be the case that the receiving terminal #2 feeds back an ACK signal because both the control channel and the data channel are successful (N _C =1, N _D =1, K = 3) Therefore, since reception of the sidelink data is successful in all of the receiving terminals, the transmitting terminal may complete the transmission procedure.

As described above, it was confirmed that the sidelink control channel transmission power ramping operation according to the present disclosure can be applied not only to a unicast communication mode but also to a groupcast communication mode using feedback.

16 is a block diagram of a terminal using transmit power ramping of a sidelink control channel according to the present disclosure.

Referring to FIG. 16, a terminal may communicate with another terminal or a base station through an antenna 301, and may have a configuration for communicating with the base station. For example, the terminal may include a downlink radio frequency (RF) unit, a downlink analog to digital converter (ADC) unit 312, and a downlink path loss measurement unit 313. .

16 illustrates only configurations necessary for direct communication between devices according to the present disclosure. Accordingly, a configuration related to uplink transmission is omitted.

The downlink radio frequency (RF) unit 311 may receive a downlink radio frequency (RF) signal from the base station through the antenna 301, convert it into a baseband signal, and output the baseband analog signal. The downlink ADC unit 312 may convert a baseband analog signal into a digital signal and output the converted digital signal. The downlink path loss measurement unit 313 may measure downlink path loss in a signal received through an antenna and converted into a digital signal. This path loss measurement can be measured based on various methods, and is not limited to one specific method in the present disclosure.

In addition, the terminal may have a configuration for uplink transmission to communicate with the base station. In the following description, the "base station communication unit" may include the downlink RF unit 311, the downlink ADC unit 312, and the downlink path loss measurement unit 313 illustrated in FIG. 16 . And the base station communication unit may further include a configuration for uplink transmission. In addition, the base station communication unit may further include a modem for demodulation and decoding of a signal received from the base station or a communication processor (CP) for performing a modem function.

Next, a configuration required for sidelink communication included in the terminal will be described.

The terminal includes a sidelink RF receiver 321, a sidelink ADC unit 322, a sidelink path loss measurement unit 323, a sidelink synchronization detector 324, and a sidelink RF receiver 321 to receive signals from other terminals during sidelink communication. A link feedback detector 325 may be included. In the present disclosure, the sidelink RF receiver 321, the sidelink ADC unit 322, the sidelink path loss measurement unit 323, the sidelink synchronization detector 324, and the sidelink feedback detector 325 are collectively referred to as "sidelink It will be referred to as "receiver".

The sidelink RF receiver 321 may receive a sidelink radio frequency (RF) signal from another terminal through the antenna 301, convert the baseband signal into a baseband signal, and output the baseband analog signal. The sidelink ADC unit 322 may convert a baseband analog signal into a digital signal and output the converted digital signal. The sidelink pathloss measuring unit 323 may measure sidelink pathloss in a signal received through an antenna and converted into a digital signal. This path loss measurement can be measured based on various methods, and is not limited to one specific method in the present disclosure. The sidelink synchronization detection unit 324 may detect a sidelink synchronization signal transmitted by another terminal and synchronize with the detected synchronization signal to use for sidelink communication. The sidelink feedback detection unit 325 may detect a feedback signal from another terminal participating in sidelink communication.

In addition, the terminal includes a sidelink data channel transmission unit 334, a sidelink control channel transmission unit 335, and a sidelink digital to analog converter (DAC) unit 333 to transmit signals to other terminals during sidelink communication. ) sidelink power controller 332 and sidelink RF transmitter 331. In the present disclosure, a sidelink data channel transmission unit 334, a sidelink control channel transmission unit 335, and a sidelink digital to analog converter (DAC) unit 333 for transmitting signals to other terminals during sidelink communication. ) The sidelink power controller 332 and the sidelink RF transmitter 331 are collectively referred to as a "sidelink transmitter".

The sidelink data channel transmission unit 334 may process user data to be transmitted according to sidelink communication protocols, map them to data channels, and output the data. The sidelink control channel transmission unit 335 may output control information to be multiplexed to a data channel and transmitted, or map control information to be transmitted separately to a control channel and output the same. The sidelink DAC unit 333 may convert a digital signal input from the sidelink control channel transmitter 335 and/or the sidelink data channel transmitter 334 into an analog signal and output the converted analog signal. Under the control of the sidelink transmission power determining unit 326 to be described later, the sidelink power control unit 332 amplifies the control channel and/or the data channel to have power capable of being transmitted to other terminals participating in sidelink communication. can be printed out. The sidelink RF transmission unit 331 band-raises the power-amplified data of each channel into a radio frequency (RF) signal and transmits the power-amplified data of each channel to other terminals participating in sidelink communication through the antenna 301.

Meanwhile, although the feedback transmission unit is not separately illustrated in FIG. 16, the sidelink transmission unit may further include a feedback transmission unit. When receiving a control channel and/or a data channel through the sidelink, the feedback transmission unit generates an ACK/NACK signal for feedback to the transmitting terminal in response to demodulation and decoding results, or ACK-NO based, ACK or transmission may not generate a feedback signal to When the feedback transmission unit generates a response signal to be transmitted, it may be fed back to the transmitting terminal through the same path as the sidelink control channel transmission unit 335 or the sidelink data channel transmission unit 334.

In addition, the terminal may include a sidelink transmission determining unit 327, a sidelink transmission power determining unit 326, and a sidelink control unit 302 for controlling sidelink communication. The sidelink transmission determination unit 327 and the sidelink transmission power determination unit 326 may be implemented by being integrated into the sidelink control unit 302 according to an implementation method. In addition, the sidelink control unit 302 may be performed in a part of a communication processor including a modem, and the communication processor, sidelink transmission determination unit 327, and sidelink transmission power determination unit 326 described below. ) may be implemented in a form including control logic for the operation. In FIG. 16 according to the present disclosure, the characteristics of each function are separately functionally illustrated in order to distinguish and explain.

The sidelink transmission determination unit 327 may control the output of the sidelink data channel transmission unit 334 and/or the sidelink control channel transmission unit 335 based on information received from the sidelink feedback detection unit 325. there is. In the case of using the methods described in FIGS. 7 and 8 , transmission may be determined depending on whether the response signal is an ACK or a NACK. According to FIG. 9, it is possible to determine whether to transmit a sidelink based on a response signal about whether a control channel is received. As another example, based on the contents described above with reference to FIGS. 14 and 15, when the transmitting terminal communicates with a plurality of receiving terminals and receives an ACK as feedback on the control channel, the sidelink transmission determining unit 327 Data can be controlled to be output through the sidelink data channel transmission unit 334 and the sidelink control channel transmission unit 335 . On the other hand, when the transmitting terminal communicates with a plurality of receiving terminals and does not receive any signal as feedback on the control channel, the sidelink transmission determining unit 327 blocks the sidelink data channel transmitting unit 334, and It can be controlled to be output only from the link control channel transmission unit 335.

In addition, the sidelink transmission power determination unit 326 may determine transmission power by using the downlink path loss measurement result using the signal received from the base station communication unit and utilizing the sidelink path loss result measured by the sidelink reception unit. . Such transmit power may be determined according to the method described in FIGS. 10A and 10B or 12A and 12B or 13A and 13B. In particular, when the sidelink transmission power determination unit 326 determines the power for the sidelink control channel, information from the sidelink feedback detection unit 325 may be utilized. Accordingly, the sidelink transmission power determining unit 326 may store the preset power increase value described above.

The sidelink control unit 302 controls each functional block of a transmitting terminal using transmit power ramping of a control channel in a sidelink that provides direct communication between terminals according to the embodiments described in the present disclosure and controls operations. can do.

The operation of the method according to the embodiment of the present invention can be implemented as a computer readable program or code on a computer readable recording medium. A computer-readable recording medium includes all types of recording devices in which information that can be read by a computer system is stored. In addition, computer-readable recording media may be distributed to computer systems connected through a network to store and execute computer-readable programs or codes in a distributed manner.

In addition, the computer-readable recording medium may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, and flash memory. The program command may include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine code generated by a compiler.

Although some aspects of the present invention have been described in the context of an apparatus, it may also represent a description according to a corresponding method, 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 may also be represented by a corresponding block or item or a corresponding feature of a device. Some or all of the method steps may be performed by (or using) a hardware device such as, for example, a microprocessor, programmable computer, or electronic circuitry. In some embodiments, at least one or more of the most important method steps may be performed by such a device.

In embodiments, a programmable logic device (eg, a field programmable gate array) may be used to perform some or all of the functions of the methods described herein. In embodiments, a field-programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein. Generally, methods are preferably performed by some hardware device.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the claims below. You will understand that you can.

Claims (20)

In the sidelink communication method in the first terminal,
determining a first power value of a first control channel for transmitting control information for the sidelink communication based on open loop power control;
transmitting the control information through the first control channel having the first power value;
determining a second power value of a first data channel for transmitting data when a response signal corresponding to the control information is received; and
Transmitting a second control channel and the first data channel in one predetermined slot for the sidelink communication; includes,
Here, the third power value of the second control channel and the second power value of the first data channel are determined based on at least the power value of the first control channel.
Sidelink communication method in a first terminal. The method of claim 1,
When the second power value and the third power value are determined, the open loop power control information at the transmission time of the first data channel is further used.
Sidelink communication method in a first terminal. The method of claim 1,
Transmitting the control information through a third control channel until a preset condition is satisfied when a response signal corresponding to the control information is not received; further comprising,
The power value of the third control channel is increased by a predetermined value to the power value of the first control channel.
Sidelink communication method in a first terminal. The method of claim 3,
The preset condition includes the number of transmissions of the control channel.
Sidelink communication method in a first terminal. The method of claim 3,
Determining a power value of the third control channel as a preset power value when the power value of the third control channel exceeds a preset maximum power,
Sidelink communication method in a first terminal. The method of claim 1,
The response signal corresponding to the control information,
Including one of an acknowledgment (ACK) indicating success of demodulation and decoding of the control information and a no response (No Signal) indicating failure of demodulation and decoding of the control information,
Sidelink communication method in a first terminal. The method of claim 6,
Increasing the third power value by a preset value when the negative response is received;
Sidelink communication method in a first terminal. In the sidelink communication method in the first terminal,
Transmitting control information for the sidelink communication to a plurality of receiving terminals through a first control channel;
When a response signal corresponding to the first control channel is received from a first receiving terminal among the plurality of receiving terminals, a second control channel and a first data channel are transmitted in one predetermined slot for the sidelink communication. doing;
A response signal corresponding to the second control channel and the first data channel is received from the first receiving terminal, and a response corresponding to the second control channel or a response signal corresponding to the second control channel is received from at least one of other receiving terminals. Excluding the first receiving terminal from the terminals to receive the sidelink data when the response signal corresponding to the first data channel is not received;
Transmitting the control information through a third control channel; and
Transmitting a fourth control channel and a second data channel in one predetermined slot for the sidelink communication when a response signal corresponding to the third control channel is received from a second receiving terminal among the plurality of receiving terminals Step; including,
Here, the first data channel and the second data channel transmit the same sidelink data,
Sidelink communication method in a first terminal. The method of claim 8,
A response signal corresponding to the second control channel and the first data channel is received from the first receiving terminal, and a response signal corresponding to the second control channel and the first data channel is received from a third receiving terminal. further excluding the third receiving terminal from the terminal to receive the sidelink data; further comprising,
Sidelink communication method in a first terminal. The method of claim 8,
When response signals corresponding to the second control channel and the first data channel are received from the first receiving terminal and a response to the second control channel is received from the third receiving terminal, the fifth control channel and the second control channel are received. Transmitting 3 data channels; further comprising,
Here, the third data channel transmits the same sidelink data as the first data channel and the second data channel.
Sidelink communication method in a first terminal. The method of claim 8,
determining a first power value of the first control channel based on open loop power control;
A second power value of the first data channel, a third power value of the second control channel, and a fourth power value of the third control channel are determined based on transmit power of the first control channel, and
The fifth power value of the fourth control channel and the sixth power value of the second data channel are determined based on the fourth power value.
Sidelink communication method in a first terminal. The method of claim 11,
Transmitting the control information through a third control channel until a preset condition is satisfied when there is no response from all of the plurality of receiving terminals; further comprising,
The power value of the third control channel is increased by a predetermined value to the power value of the first control channel.
Sidelink communication method in a first terminal. The method of claim 12,
The preset condition includes the number of transmissions of the control channel,
Determining a power value of the third control channel as a preset power value when the power value of the third control channel exceeds a preset maximum power,
Sidelink communication method in a first terminal. In the first terminal for sidelink communication,
a sidelink receiving unit for receiving a sidelink signal from another terminal;
a side link transmission unit for transmitting a side link signal to another terminal; and
A controller comprising at least one processor, wherein the controller:
Determine a first power value of a first control channel for transmitting control information for the sidelink communication based on open loop power control;
Controlling the sidelink transmitter to transmit the control information through the first control channel having the first power value;
determining a second power value of a first data channel for transmitting data when a response signal corresponding to the control information is received from the sidelink receiver; and
Controls the sidelink transmission unit to transmit a second control channel and the first data channel in one predetermined slot for the sidelink communication;
Here, the third power value of the second control channel and the second power value of the first data channel are determined based on at least the power value of the first control channel.
A first terminal for sidelink communication. The method of claim 14,
Wherein the controller further determines the second power value and the third power value by using open loop power control information at a transmission time of the first data channel when determining the third power value.
A first terminal for sidelink communication. The method of claim 14,
The controller:
Further controlling the sidelink transmission unit to transmit the control information through a third control channel until a preset condition is satisfied when a response signal corresponding to the control information is not received, and
The power value of the third control channel is increased by a predetermined value to the power value of the first control channel.
A first terminal for sidelink communication. The method of claim 16
The preset condition includes the number of transmissions of the control channel.
A first terminal for sidelink communication. The method of claim 16
The controller determines the power value of the third control channel as a preset power value when the power value of the third control channel exceeds a preset maximum power when the increase,
A first terminal for sidelink communication. The method of claim 14,
The response signal corresponding to the control information,
Including one of an acknowledgment (ACK) indicating success of demodulation and decoding of the control information and a no response (No Signal) indicating failure of demodulation and decoding of the control information,
A first terminal for sidelink communication. The method of claim 19
Increasing the third power value by a preset value when the negative response is received;
A first terminal for sidelink communication.

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