Method and apparatus for automatic gain control in vehicle-to-everything system

Abstract

The present disclosure relates to a communication method and system for integrating a fifth generation (5G) communication system, which uses IoT technology to support higher data rates than fourth generation (4G) systems. The present disclosure can be applied to smart services based on 5G communication technology and IoT-related technologies, such as smart homes, smart buildings, smart cities, smart cars, connected cars, health care, digital education, smart retail, safety and security services. A method performed by a first terminal in a wireless communication system is provided, the method comprising: determining whether to send a preamble for automatic gain control (AGC); in the case of determining to send a preamble for AGC, determining a time slot for sending a preamble for the AGC and at least one symbol in the time slot; and sending the preamble for AGC to a second terminal in the determined time slot and on at least one symbol in the time slot.

Description

Technical Field

[0001] The present disclosure generally relates to a mobile communication system, and more particularly, to a method and apparatus for more efficiently performing automatic gain control (AGC) and data signal reception by a terminal (i.e., user equipment (UE)) supporting vehicle-to-everything (V2X) communication. Background Art

[0002] In order to meet the demand for increased wireless data traffic since the deployment of 4G communication systems, efforts have been made to develop improved 5G or quasi-5G (pre-5G) communication systems. Therefore, 5G or quasi-5G communication systems are also referred to as "quasi-4G networks" or "post-LTE systems". 5G communication systems are considered to be implemented in higher frequency (millimeter wave) bands, such as the 60GHz band, in order to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technology are discussed in 5G communication systems. In addition, in 5G communication systems, based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, collaborative communications, coordinated multi-point (CoMP), receiving-end interference elimination, etc., are being developed for system network improvements. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies have been developed.

[0003] The Internet, a human-centered connected network in which humans generate and consume information, is now evolving into the Internet of Things (IoT), in which distributed entities (such as things) exchange and process information without human intervention. The Internet of Everything (IoE) has emerged, which is a combination of IoT technology and big data processing technology through connection with cloud servers. Since IoT implementation requires technical elements such as "sensing technology", "wired / wireless communication and network architecture", "service interface technology" and "security technology", sensor networks, machine-to-machine (M2M) communication, machine type communication, etc. have been studied recently. This IoT environment can provide smart Internet technology services that create new value for human life by collecting and analyzing data generated by connected things. IoT can be applied to various fields including smart homes, smart buildings, smart cities, smart vehicles or connected vehicles, smart grids, health care, smart instruments and advanced medical services through the integration and combination between existing information technology (IT) and various industrial applications.

[0004] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine type communications (MTC), and machine-to-machine (M2M) communications can be implemented through beamforming, MIMO, and array antennas. Cloud radio access networks (RANs) as an application of the above-mentioned big data processing technologies can also be considered as an example of the fusion of 5G technologies and IoT technologies. Summary of the invention

[0005] Technical issues

[0006] One aspect of the present disclosure is to provide a method and apparatus for effectively performing AGC for control and data signal reception by a UE supporting V2X in an environment supporting multiple digital systems. Another aspect of the present disclosure is to provide a configuration of a base station (gNB) and an operation of a UE for performing AGC for a terminal (i.e., UE).

[0007] Solution to the problem

[0008] According to one aspect of the present disclosure, a method performed by a first terminal in a wireless communication system includes: determining whether to send a preamble code for AGC; in the case of determining to send a preamble code for AGC, determining a time slot used to send the preamble code for AGC and at least one symbol in the time slot; and sending the preamble code for AGC to a second terminal in the determined time slot and on at least one symbol in the time slot.

[0009] According to another aspect of the present disclosure, a method performed by a second terminal in a wireless communication system includes: determining whether to receive a preamble code for AGC; in the case where it is determined that the preamble code for AGC is received, monitoring a time slot used to receive the preamble code for AGC and at least one symbol in the time slot; and receiving the preamble code for AGC from a first terminal in the time slot and on at least one symbol in the time slot, wherein, in the case where it is determined by the first terminal to send a preamble code for AGC, the time slot used to receive the preamble code for AGC and at least one symbol in the time slot are determined by the first terminal.

[0010] According to another aspect of the present disclosure, a first terminal in a wireless communication system includes: a transceiver, which is configured to communicate with other network entities; and a controller, which is configured to: determine whether to send a preamble code for AGC; in the case of determining to send the preamble code for AGC, determine a time slot and at least one symbol in the time slot used to send the preamble code for AGC; and send the preamble code for AGC to a second terminal in the determined time slot and on at least one symbol in the time slot.

[0011] According to another aspect of the present disclosure, a second terminal in a wireless communication system includes: a transceiver, which is configured to communicate with other network entities; and a controller, which is configured to: determine whether to receive a preamble code for AGC; in the case of determining to receive the preamble code for AGC, monitor the time slot used to receive the preamble code for AGC and at least one symbol in the time slot; and receive the preamble code for AGC from the first terminal in the time slot and on at least one symbol in the time slot, wherein, in the case of determining by the first terminal to send the preamble code for AGC, the time slot used to receive the preamble code for AGC and at least one symbol in the time slot are determined by the first terminal.

[0012] Beneficial Effects of the Invention

[0013] The present disclosure is to solve the above-mentioned problems and disadvantages and to provide at least the advantages described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description in conjunction with the accompanying drawings, in which:

[0015] Figure 1A is a diagram illustrating V2X communication in a cellular system according to an embodiment;

[0016] Figure 1B is a diagram illustrating a demodulation reference signal (DMRS) pattern considered for V2X according to an embodiment;

[0017] Figure 1C is a diagram showing two methods of allocating a physical sidelink control channel (PSCCH) and a PSSCH by frequency division multiplexing (FDM) according to an embodiment;

[0018] Figure 1D is a diagram illustrating DMRS patterns (Type 1 and Type 2) for communication between a next generation NodeB (gNB) and a UE in a new radio (NR) system according to an embodiment;

[0019] Figure 1E is a diagram showing a partial structure of a receiver of a UE for performing AGC according to an embodiment;

[0020] Figure 1F is a diagram showing an example of signal strength through an amplifier when AGC is performed if an Orthogonal Frequency Division Multiplexing (OFDM) symbol is received over time according to an embodiment;

[0021] Figure 1Gis a diagram illustrating performance degradation of an ACG determination time according to a short symbol length supporting a wide length subcarrier spacing according to an embodiment;

[0022] Figure 1H is a diagram illustrating a first method and a second method according to an embodiment;

[0023] Fig. 1I is a diagram illustrating an operation of a UE according to a first method according to an embodiment;

[0024] Figure 1J is a diagram illustrating an operation of a UE according to a second method according to an embodiment;

[0025] Figure 1K is a diagram showing a DMRS position when a symbol length of a scheduled PSSCH is 7 and when the number of additional DMRSs is configured as 1 according to an embodiment;

[0026] Figure 1L is a block diagram showing an internal structure of a UE according to an embodiment; and

[0027] Figure 1M is a block diagram showing the internal structure of a gNB according to an embodiment.

[0028] Figure 2 A case where four subchannels starting from the third subchannel are allocated to the PSSCH is shown.

[0029] FIG. 3A to FIG. 3E The transmission position of the PSCCH in the side link is shown.

[0030] Best Mode for Carrying Out the Invention

[0031] Various embodiments of the present disclosure are described with reference to the accompanying drawings. However, the various embodiments of the present disclosure are not limited to specific embodiments, and it should be understood that various modifications, equivalents and or substitutions may be made to the embodiments described herein. With respect to the description of the accompanying drawings, the same components may be marked with the same reference numerals.

[0032] When describing the following disclosure, when it is determined that its detailed description may unnecessarily obscure the subject matter of the present disclosure, the detailed description of the related known configuration or function incorporated herein will be omitted. The terms to be described below are defined in consideration of the functions in the present disclosure, and may differ depending on the user, the user's intention or habit. Therefore, the definition of the term should be based on the content of the entire specification.

[0033] For the convenience of description, the terms used in the following description to identify connection nodes, terms related to network entities, terms related to messages, terms related to interfaces between network entities, and terms related to various types of identification information are shown. Therefore, the present disclosure is not limited to the terms provided below, and other terms indicating subjects with equivalent technical meanings may be used.

[0034] For convenience of description, the present disclosure uses terms and names defined in the 3rd Generation Partnership Project LTE (3GPP LTE). However, the present disclosure is not limited to the above terms and names, and can be equally applied to systems conforming to other standards such as 3GPP NR.

[0035] Figure 1A is a diagram illustrating V2X communication in a cellular system according to an embodiment.

[0036] V2X collectively refers to the communication technology through all interfaces with vehicles, including vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) and vehicle-to-pedestrian (V2P), depending on its shape and the components that make up the communication. V2P and V2V fundamentally follow the structure and working principle of Rel-13 device-to-device (D2D).

[0037] refer to Figure 1A , gNB a-01 includes at least one vehicle UE a-05, a-10, a-11, and a-12 and a pedestrian portable UE a-15 located in a V2X-supported cell a-02. That is, the vehicle UE a-05 performs cellular communication with the gNB a-01 using the vehicle UE to gNB links Uua-30 and a-35, and performs D2D communication with other vehicle UEs a-10, a-11, and a-12 or pedestrian portable UE a-15 using side links (PC5) a-20, a-21, a-22, and a-25. In order for the vehicle UE a-05 to directly exchange information with other vehicle UEs and pedestrian portable UEs using the side links, the gNB must allocate a resource pool that can be used for side link communication.

[0038] In the LTE system, resource allocation can be divided into two types, scheduled resource allocation (mode 3) and UE autonomous resource allocation (mode 4), according to the method by which the gNB allocates resources to the UE for V2X sidelink communication. In the case of scheduled resource allocation, the gNB allocates resources for sidelink transmission to the UE of the radio resource control connection (RRC) in a dedicated scheduling manner. The above method is effective for interference management and resource pool management (dynamic allocation and semi-persistent transmission) because the gNB can manage the resources of the sidelink. In the case of scheduled resource allocation (mode 3) in which the gNB allocates and manages resources for V2X, when the UE connected to the RRC has data to be sent to other UEs, the data can be sent to the gNB using an RRC message or a medium access control (MAC) control element (CE). In this case, SidelinkUEInformation and UEAssistanceInformation messages can be used as RRC messages. At the same time, the MAC CE can be, for example, a buffer status report MAC CE of a new format (including at least an indicator indicating that the corresponding report is a buffer status report for V2P communication and information about the size of data buffered for D2D communication). The detailed format and content of the buffer status report used by 3GPP are based on the 3GPP standard TS36.321 "E-UTRA MAC protocol specification". On the other hand, in the case of UE autonomous resource allocation, the gNB provides the sidelink transmit / receive resource pool for V2X as system information, and the UE selects the resource pool according to a predetermined rule. The resource selection method may include area mapping or sensing-based resource selection and random selection.

[0039] Figure 1B is a diagram illustrating a DMRS pattern considered for V2X according to an embodiment.

[0040] Since V2X is vehicle-to-vehicle communication, the UE’s reception performance must be guaranteed even in high-speed mobile environments. Figure 1B As shown, in the LTE system, four DMRSs are allocated to symbol indexes {2, 5, 8, 11} for PSCCH and physical sidelink shared channel (PSSCH), and three DMRSs other than symbols for primary sidelink synchronization signal (PSSS) and secondary sidelink synchronization signal (SSSS) are allocated to symbol indexes {5, 7, 10} for physical sidelink broadcast channel (PSBCH).

[0041] Therefore, considering the channel estimation performance and frequency offset estimation performance of the side link, the DMRS structure is designed by minimizing the interval of DMRS symbols. In addition, since the V2X service exchanges information related to vehicle safety, the delay time of transmission and reception should be minimized to ensure the safety between vehicles. To this end, Figure 1CAs shown, a frequency division multiplexing (FDM) method of simultaneously transmitting a data channel and a control channel in different frequency domains in the same subframe is used. Therefore, by simultaneously receiving the data channel and the control channel to simultaneously process them, the delay time can be reduced.

[0042] Figure 1C 2 is a diagram showing two methods of allocating a PSCCH and a PSSCH through FDM according to an embodiment.

[0043] refer to Figure 1C , c-10 indicates a non-contiguous allocation scheme that separates PSCCH and PSSCH allocation resource regions in one subframe to support transmission and reception of multiple V2X UEs. c-20 indicates a contiguous allocation scheme that continuously allocates PSCCH and PSSCH to one subchannel to support transmission and reception of multiple V2X UEs.

[0044] Figure 1D is a diagram showing DMRS patterns (Type 1 and Type 2) used for communication between a gNB and a UE in an NR system according to an embodiment.

[0045] In the NR system, two DMRS modes are supported. Figure 1D Two DMRS modes are described in detail. Figure 1D In the figure, d-10 and d-20 represent DMRS type 1, where d-10 represents one symbol pattern and d-20 represents two symbol patterns.

[0046] DMRS type 1 of d-10 or d-20 is a DMRS pattern of a comb 2 structure, which can be composed of two code division multiplexing (CDM) groups, and FDM is performed on different CDM groups. Specifically, in d-10 and d-20, each part marked with green represents CDM group 0, and each part marked with red represents CDM group 1.

[0047] In the single symbol mode of d-10, two DMRS ports can be distinguished by applying CDM of one frequency to the same CDM group, where a total of four orthogonal DMRS ports can be configured. The DMRS port identifiers (IDs) mapped to the CDM groups respectively are shown in d-10 (in the case of a downlink, the DMRS port ID is represented by +1000 of the number shown).

[0048] In the dual symbol mode of d-20, four DMRS ports can be distinguished by applying CDM in time / frequency to the same CDM group, where a total of eight orthogonal DMRS ports can be configured. The DMRS port IDs mapped to the CDM groups are shown in d-20 (in the case of a downlink, the DMRS port ID is represented by +1000 of the number shown).

[0049] Different from this, DMRS type 2 of d-30 or d-40 is a structured DMRS pattern in which FD-OCC (frequency division-orthogonal cover code) is applied to adjacent subcarriers in one frequency, can be composed of three CDM groups, and FDM is performed on different CDM groups. Specifically, in d-20 and d-30, each part marked with blue represents CDM group 0, each part marked with green represents CDM group 1, and each part marked with red represents CDM group 2.

[0050] In the single symbol mode of d-30, two DMRS ports can be distinguished by applying CDM of one frequency to the same CDM group, where a total of six orthogonal DMRS ports can be configured. The DMRS port IDs mapped to the CDM groups respectively are shown in d-30 (in the case of the downlink, the DMRS port ID is represented by +1000 of the number shown).

[0051] In the dual symbol mode of D-40, four DMRS ports can be distinguished by applying CDM in time / frequency to the same CDM group, where a total of 12 orthogonal DMRS ports can be configured. The DMRS port IDs mapped to the CDM groups are shown in D-40 (in the case of the downlink, the DMRS port ID is represented by +1000 of the number shown).

[0052] As mentioned above, in the NR system, two different DMRS patterns (d-10 and d-20 or d-30 and d-40) can be configured, and whether the DMRS pattern is a single symbol pattern (d-10 and d-30) or an adjacent dual symbol pattern (d-20 and d-40) is also configurable. In addition, the gNB can not only schedule the DMRS port number, but also configure and signal the number of CDM groups scheduled together for physical downlink shared channel (PDSCH) rate matching. In the case of cyclic prefix (CP)-OFDM, in the case of supporting the above two DMRS patterns in downlink (DL) and uplink (UL), and in the case of DFT-S-OFDM (Discrete Fourier Transform-Spread-OFDM), only DMRS type 1 is supported in the above DMRS pattern of UL. Configurable additional DMRS is supported.

[0053] The pre-DMRS refers to the first DMRS that appears in the first (i.e. earliest) symbol in time, and the additional DMRS refers to the DMRS that appears in the symbol after the pre-DMRS. In the NR system, the number of additional DMRS can be configured from a minimum of zero to a maximum of three. In addition, when the additional DMRS is configured, the same mode as the pre-DMRS is assumed.

[0054] More specifically, when information indicating whether the preceding DMRS is the above-mentioned DMRS mode type 1 or type 2, information indicating whether the DMRS mode is a single symbol mode or an adjacent double symbol mode, and information about the number of CDM groups used with the DMRS port are indicated, in the case where an additional DMRS is additionally configured, the additional DMRS is configured in the same manner as the preceding DMRS.

[0055] In the case of the LTE system, when the vehicle UE a-05 performs D2D communication with other vehicle UEs a-10, a-11, and a-12 or pedestrian portable UE a-15 using side links (PC5) a-20, a-21, a-22, and a-25, as described above with reference to Figure 1A As described above, the vehicle UE a-05 is supported only in the form of simultaneously transmitting data to a plurality of non-specific nodes a-10, a-11, a-12 and a-15 by broadcasting.

[0056] However, in the NR system, support can be considered as a form in which the vehicle UE a-05 sends data to only one specific node through unicast or sends data to multiple specific nodes through groupcast. For example, such unicast and groupcast techniques can be effectively used to consider service scenarios such as platooning, which is a technology that connects two or more vehicles through one network and bundles and moves in a cluster.

[0057] Specifically, in order for the leader node of a group connected by a queue to control a specific node, unicast communication may be required, and in order to simultaneously control a group consisting of multiple specific nodes, multicast communication may be required. In particular, since the relative speed between nodes in the queue is very small, considering only the high-speed mobile environment of V2X (such as in the LTE system), it may be inefficient to determine the DMRS pattern of the side link by minimizing the interval of DMRS symbols. In addition, considering the flexible DMRS pattern configuration considered in the NR system, information on the method of configuring a DMRS pattern suitable for the V2X scenario is required.

[0058] Table 1 shows various numbers defined in the NR system. The subcarrier spacing Δf is determined according to the number μ, and the supported cyclic prefix (CP) length is determined. Table 1 shows the OFDM symbol and cyclic prefix length according to numerology.

[0059] Table 1

[0060] μ <![CDATA[Δf=2 μ ·15[kHz]]]> Cyclic prefix Symbol duration [μsec] CP length [μsec] 0 15 normal 66.67 4.69 1 30 normal 33.33 234 2 60 Normal, Extended 1667 1.17 (for ECF 4.17) 3 120 normal 8.33 0.59 4 240 normal 417 0.29

[0061] Table 2 and Table 3 show the number of OFDM symbols per slot, the number of slots per frame, and the number of slots per subframe in the normal CP and the extended CP, respectively.

[0062] Table 2

[0063]

[0064] Table 3

[0065]

[0066] In the NR system, Type A and Type B are defined as PDSCH or PUSCH mapping types. In PDSCH or PUSCH mapping type A, the first symbol of the DMRS symbol is located in the second or third OFDM symbol of the time slot, while in PDSCH or PUSCH mapping type B, the first symbol of the DMRS symbol is located in the first OFDM symbol of the time domain resources allocated for PUSCH transmission. In the case of data transmission for PDSCH or PUSCH, the time domain resource allocation can be transmitted by information about the time slot of the transmitted data and the starting symbol position S in the corresponding time slot and the number of symbols L to which the data is mapped. In the above, S can be the relative position from the beginning of the time slot, L can be the number of consecutive symbols, and S and L can be determined according to the start and length indication value (SLIV) defined as follows.

[0067] If (L-1)≤7, then

[0068] SLIV=14·(L-1)+S

[0069] otherwise

[0070] SLIV=14·(14-L+1)+(14-1-S)

[0071] Where 0 <L≤14-S

[0072] In the NR system, in general, the RRC configuration may allow the UE to receive a configuration of a table that includes the SLIV value, the PDSCH or PUSCH mapping type, and information about the time slot in which the PDSCH or PUSCH is transmitted in one row. Thereafter, for the purpose of time domain resource allocation of the DCI, the gNB indicates the index value in the configuration table so that the gNB can send the SLIV value, the PDSCH or PUSCH mapping type, and information about the time slot in which the PDSCH or PUSCH is transmitted to the UE.

[0073] Considering various digital hierarchies and time domain resource allocation methods for data transmission defined in the above-mentioned NR system, the AGC problem in the V2X communication environment is described. First, with respect to AGC, when receiving a signal, the UE performs an operation of amplifying the received signal. Determining how much the signal is amplified in the amplification operation may depend on the strength of the signal and the dynamic range of the UE amplifier.

[0074] The dynamic range is the range of signal strengths in which the input and output of the amplifier have a linear relationship. If the input and output of the amplifier do not have a linear relationship and the phase of the signal is arbitrarily changed, the corresponding signal may not be available for data reception. However, if the amplified strength is too large, the signal will not be amplified beyond a predetermined strength, and the phase of the signal is arbitrarily changed, so the UE cannot arbitrarily amplify the received signal. Moreover, if the amplified strength is too small, the data reception performance may be reduced. Therefore, the UE needs to amplify the received signal with an appropriate strength. Therefore, when the UE performs amplification, it may be important to first find out the strength of the received signal. For example, this can be an operation of reducing the degree of amplification when the strength of the received signal is too large, and an operation of increasing the degree of amplification when the received signal is too small. As described above, the UE needs to change the degree of amplification according to the strength of the received signal, and this operation is called AGC.

[0075] Figure 1E is a diagram showing a partial structure of a receiver of a UE for performing AGC according to an embodiment.

[0076] refer to Figure 1E , the received signal (input signal) of the UE is first amplified by a variable gain amplifier (VGA) e-10, and the amplified signal is sent to a detector e-20 that estimates the amplification strength. The signal strength estimated in this way is compared with a set point determined by the dynamic range of the UE, and the error amplifier e-30 confirms the difference between the two and sends the gain control to the parameters of the VGA. The degree of amplification is determined in the VGA according to the difference between the estimated signal strength and the set point, and the degree of amplification is used to allow the amplified signal to be included in the dynamic range of the UE amplifier. As a result, the AGC operation can be a process of determining how much the received signal is amplified.

[0077] Figure 1F is a diagram showing an example of signal strength through an amplifier when AGC is performed if OFDM symbols (CP-OFDM or DFT-S-OFDM symbols) are received over time according to an embodiment.

[0078] refer to Figure 1F , when receiving a signal, the UE performs an AGC operation and requires time to determine the degree of amplification in order to amplify the received signal with appropriate strength. The time taken to determine the appropriate degree of amplification of the amplifier by AGC may be referred to as AGC establishment time. The UE determines the degree of amplification by performing AGC during the first partial cycle of receiving control and data signals. Since the signal received during the AGC establishment time is unreliable, the signal may be difficult to use for decoding data or control signals. Therefore, a signal based on the value f-12 that stabilizes after the AGC establishment time may be used for decoding data or control signals.

[0079] Figure 1F It shows the time taken by AGC according to the symbol length when the AGC setup time is 15 μsec, and the symbol length is based on various numbers defined in the NR system shown in Table 1 above. Figure 1F f-10, f-20, f-30 and f-40 in the figure show the cases where the subcarrier spacing is 15KHz, 30KHz, 60KHz and 120KHz respectively.

[0080] When the subcarrier spacing is 120kHz, the AGC setup time may occupy two symbols as shown in f-40. Unlike this, the AGC setup time may occupy one symbol in the subcarrier spacing corresponding to f-10, f-20, and f-30. In this case, the symbol corresponding to the AGC setup time may be difficult to use for decoding data or control signals.

[0081] In addition, in the LTE system, only QPSK and 16QAM are supported as modulation rates for PSSCH transmission, but in the V2X sidelink transmission of the NR system, high modulation rates such as 64QAM can be supported. Compared with low modulation rates, high modulation rates may require longer AGC establishment time.

[0082] In addition, flexible scheduling and shorter transmission time interval (TTI) lengths are supported, resulting in a larger proportion of AGC establishment time compared to scheduling of all 14 symbols. Therefore, the longer the AGC establishment time, the lower the relative transmission efficiency. If the AGC establishment part includes a reference signal (RS), there may be serious problems with reception performance because the RS cannot be used for channel estimation. For example, the above-mentioned pre-placed DMRS needs to take AGC into account for positioning. Therefore, due to the above-mentioned problems in the NR system, the method of performing AGC needs to be changed.

[0083] As described above, factors to be considered when performing AGC in the NR V2X sidelink communication system that are different from those in the conventional LTE system have been described. Therefore, in view of these issues, an embodiment of the present disclosure provides a method for performing AGC. Another embodiment of the present disclosure provides an operation method of the gNB and UE required when performing AGC according to the method provided in the first embodiment.

[0084] According to an embodiment, a method and apparatus for effectively performing AGC by a UE performing NR V2X sidelink control and data signal reception is provided. As described above, in order to operate an NR system, especially NR V2X, the method for effectively performing AGC needs to effectively perform AGC in the NR sidelink communication system by considering the following four (4) factors:

[0085] 1. Short symbol length supported by wide subcarrier spacing.

[0086] 2. Supporting high modulation rates requires a longer AGC setup time.

[0087] 3. Support increased ratio of AGC setup part according to flexible scheduling and short TTI length.

[0088] 4. The position of the RS transmitted in the symbol before the time domain of the transmission control and data signals.

[0089] A method of performing AGC according to Factor 4 will be described according to another embodiment.

[0090] As above reference Figure 1F As described above, the number of symbols occupied by the AGC setup time can vary according to the subcarrier spacing. Specifically, as the subcarrier spacing increases, the number of symbols occupied by the AGC setup time will also increase.

[0091] In addition, the AGC setup time required to perform AGC should be determined so that reception performance is not degraded, and the AGC setup time should not be too long so that transmission efficiency is not degraded.

[0092] If, in order to perform AGC, only symbols for sending data and control signals are sent / received without separate signals, the receiver must use the first symbol of the data and control signals to perform AGC, so the first symbol cannot be used to decode the data and control signals. As a result, the reception performance of the data and control signals inevitably deteriorates. On the other hand, if a dedicated signal or preamplifier for performing AGC is sent before sending the data and control signals, even if AGC is not performed again when the data and control signals are received, the receiving power amplification level can be set by the dedicated signal or preamble code previously sent for performing AGC. However, since frequency and time resources are used to send a dedicated signal or preamble code for performing AGC, frequency and time resources may not be used for another data transmission, thereby reducing frequency utilization efficiency.

[0093] Therefore, based on the above factors 1 to 3, a method of performing AGC is provided.

[0094] Figure 1G is a diagram illustrating performance degradation of an ACG determination time according to a short symbol length supporting a wide length subcarrier spacing according to an embodiment.

[0095] refer to Figure 1G, in g-10 and g-20, the experimental environment is shown. As shown in g-10 and g-20, in the experiment according to the figure, it is assumed that the experiment is performed on the data channel and the DMRS is located in the third and twelfth symbols. g-10 represents the case where the preamble code for AGC is not sent, and g-20 represents the case where the preamble code for AGC is sent in the first symbol of the time slot.

[0096] In g-30, the result is shown assuming that 0 / 3 / 6 / 9 / 12 / 15 microseconds (μsec) are required as the AGC setup time when the subcarrier spacing is 60 kilohertz (kHz).

[0097] It can be seen from the results of g-30 that when the subcarrier spacing is 60kHz, the performance decreases significantly as the AGC setup time increases. This is because the received signal cannot be used for decoding when the AGC operation is performed. Even if the AGC setup time is 3μs, the performance is reduced by about 30% compared to the maximum transmission efficiency. In the low frequency range (FR1) in the NR sidelink communication system, {15, 30, 60}KHz can be considered as the subcarrier spacing, while in the high frequency range (FR2), {60, 120}KHz can be considered as the subcarrier spacing. Based on the experimental results, the present disclosure provides a method for effectively performing AGC in an NR sidelink communication system.

[0098] In particular, the method is a method of configuring a preamble code for effectively performing AGC in an NR sidelink communication system.

[0099] The method may be a method of maintaining a time domain in which control information and a data signal are transmitted according to a subcarrier spacing and inserting a preamble into a previous (ie, immediately preceding) symbol.

[0100] For example, when the control and data signals are mapped from the 0th symbol of time slot n, the preamble is transmitted from the last symbol or the last two symbols of time slot n-1. Alternatively, the preamble may not be defined in units of OFDM symbols, but may be transmitted with a predetermined or indicated length or a length defined as a fixed value, for example, a length corresponding to 15 μsec.

[0101] In the case of FR1, for the subcarrier spacing corresponding to 60KHz, a preamble of a single symbol length is inserted. However, no preamble is inserted for the subcarrier spacing corresponding to 15KHz and 30KHz.

[0102] In the case of FR2, for a subcarrier spacing corresponding to 60 KHz, a preamble of one symbol length is inserted. However, for a subcarrier spacing corresponding to 120 KHz, a preamble of two symbols length is inserted.

[0103] In the case of FR2, considering the preamble overhead, a single-symbol-length preamble can be inserted for 120KHz in the same way as for 60KHz.

[0104] In addition, a method of inserting a preamble into the first symbol or the first two symbols in the time domain and transmitting control and data signals after the preamble is provided, wherein the control and data signals are transmitted according to a subcarrier spacing.

[0105] For example, if the control and data signals are allocated to be mapped from the 0th symbol of time slot n, the preamble is transmitted from the first or first two symbols of time slot n. Alternatively, the preamble may not be defined in units of OFDM symbols, but may be transmitted with a predetermined or indicated length or a length defined as a fixed value, for example, a length corresponding to 15usec.

[0106] In the case of FR1, a preamble of one symbol length is inserted for a subcarrier spacing corresponding to 60 KHz, whereas no preamble is inserted for subcarrier spacing corresponding to 15 KHz and 30 KHz.

[0107] In the case of FR2, for a subcarrier spacing corresponding to 60 KHz, a preamble of one symbol length is inserted. However, for a subcarrier spacing corresponding to 120 KHz, a preamble of two symbols length is inserted.

[0108] In the case of FR2, taking into account the preamble overhead, a preamble of one symbol may be inserted for 120KHz in the same manner as for 60KHz.

[0109] The preamble refers to a signal transmitted by a UE transmitting a control and data signal so that the UE receiving the control and data signal performs AGC, and may be replaced by other terms.

[0110] Figure 1H is a diagram illustrating method 1 and method 2 according to an embodiment.

[0111] Will refer to Figure 1H Describe Method 1 and Method 2 in detail.

[0112] As mentioned above, in the case of LTE V2X sidelink, FDM is used in the same subframe, through which the data channel and the control channel are transmitted simultaneously in different frequency domains, such as Figure 1C However, in the case of the NR V2X side link, a method in which FDM is performed on a data channel and a control channel and a method in which time division multiplexing (TDM) is performed on a data channel and a control channel may be considered together.

[0113] Specifically, refer to Figure 1HIn h-10, h-20, h-30 and h-40, a method for multiplexing a data channel and a control channel in an NR V2X side link is shown. The methods of h-10, h-20, h-30 and h-40 will be described below.

[0114] Regarding h-10, the control channel and the data channel associated with the control channel are non-overlapping and are transmitted in the same resource in time. In addition, the frequency resources used by the two channels are the same.

[0115] Regarding h-20, the control channel and the data channel associated with the control channel are non-overlapping and are transmitted in the same resource in time. In addition, the frequency resources used by the two channels may be different.

[0116] Regarding h-30, the control channel and the data channel associated with the control channel do not overlap in frequency resources and are transmitted as time resources. In addition, the time resources used by the two channels are the same.

[0117] Regarding h-40, part of the control channel and the data channel associated with the part of the control channel overlap in time on the resource and are transmitted as non-overlapping frequency resources. In addition, another associated data channel or part of another control channel is transmitted in time in the resource in a non-overlapping manner.

[0118] In the case of h-10, h-20, h-30 and h-40, the control channel occupies one symbol and the data channel occupies five symbols. The actual number of symbols used to transmit the control channel and the data channel may vary.

[0119] According to method 1, a method of maintaining a time domain in which control and data signals are transmitted according to the subcarrier spacing and inserting a preamble into the immediately preceding symbol is shown in h-11, h-21, h-31, and h-41. Here, an example of a case where one preamble is inserted is shown. In addition, h-11, h-21, h-31, and h-41 respectively show examples of method 1 according to methods h-10, h-20, h-30, and h-40, in which a data channel and a control channel are multiplexed.

[0120] According to method 1, when scheduling of control and data signals is performed in the first symbol of a slot, the preamble may be inserted into the last symbol position of the previous slot.

[0121] Fig. 1I is a diagram illustrating an operation of a UE according to method 1 according to an embodiment.

[0122] Will refer to Fig. 1IThe operation of the UE according to method 1 is described in detail. According to method 1, in step i-01, the UE sends control and data signals. In step i-02, it is determined whether a preamble needs to be inserted according to the subcarrier spacing. If the preamble needs to be inserted according to the subcarrier spacing, then in step i-03, the preamble is sent to the symbol immediately before the corresponding control and data signal. If the scheduling of the control and data signals is performed in the first symbol of the time slot, the UE can send the time slot in advance before sending the control and data signals, and can send the preamble at the last symbol position of the time slot. If it is determined in step i-02 that it is not necessary to insert the preamble according to the subcarrier spacing, only the control and data signals are sent without inserting the preamble in step i-04. According to method 1, in step i-11, the UE receives the control and data signals. In step i-12, it is determined whether to perform the preamble reception for AGC according to the subcarrier spacing. If it is determined that the preamble reception for AGC is performed according to the subcarrier spacing, in step i-13, the preamble is received by monitoring the previous symbol of the received signal. If it is determined in step i-12 that there is no need to receive the preamble code for AGC according to the subcarrier spacing, the control and data signals are immediately received in step i-14.

[0123] At the same time, according to method 2, by Figure 1H H-12, h-22, h-32 and h-42 show a method of inserting a preamble code into a symbol before a time domain in which control and data signals are sent at a subcarrier interval, and sending the control and data signals after the preamble code.

[0124] Here, an example of the case where one preamble is inserted is shown. In addition, h-12, h-22, h-32 and h-42 respectively show examples of method 2 according to methods h-10, h-20, h-30 and h-40, in which a data channel and a control channel are multiplexed.

[0125] Figure 1J is a diagram illustrating an operation of a UE according to method 2 according to an embodiment.

[0126] Will refer to Figure 1JThe operation of the UE according to method 2 is described in detail. According to method 2, in step j-01, the UE transmits control and data signals. In step j-02, it is determined whether to perform preamble reception for AGC according to the subcarrier spacing. If the preamble reception is performed for the subcarrier spacing, in step j-3, the preamble is transmitted to the symbol before the transmitted signal. If it is determined in step j-02 that the preamble does not need to be inserted according to the subcarrier spacing (if the preamble reception is not performed for the subcarrier spacing), only the control and data signals need to be sent in step j-04 without inserting the preamble. According to method 2, in step j-11, the UE receives control and data signals. In step j-12, it is determined whether to perform preamble reception for AGC according to the subcarrier spacing. If it is determined that the preamble reception for AGC is performed for the subcarrier spacing, the preamble is received by monitoring the first symbol of the received signal in step j-13. If it is determined in step j-12 that it is not necessary to receive the preamble for AGC according to the subcarrier spacing, the control and data signals are immediately received in step j-14.

[0127] Therefore, the preamble insertion cycle according to Method 1 and Method 2 may be performed as follows.

[0128] For method 1, if a preamble needs to be inserted according to the subcarrier spacing, preamble transmission is performed for each scheduled transmission time slot.

[0129] For method 2, if a preamble needs to be inserted according to the subcarrier spacing, the preamble transmission is performed in the first scheduled transmission time slot.

[0130] In addition, another method (method 3) is possible. For example, according to method 3, if preamble insertion is required according to the subcarrier spacing, preamble transmission is performed in the first scheduled transmission time slot, but when scheduling is performed again in time slot A (i.e., the first scheduled transmission time slot) after the first time slot transmission, the preamble is not sent.

[0131] Method 1 of the preamble insertion period is a method of sending a preamble in each scheduled transmission slot, but unnecessary overhead may increase. Alternatively, its method 2 can reduce unnecessary overhead by sending the preamble in the first scheduled transmission slot. In addition, its method 3 is based on method 2, but by introducing the transmission window of time slot A, more overhead can be reduced than method 2. Depending on which method of determining the preamble insertion period is used, the UE can perform AGC by receiving the preamble only at the corresponding time point in consideration of the preamble transmission period.

[0132] Another embodiment of the present disclosure describes a method for solving problems related to the position of an RS transmitted in a symbol before the time domain of transmitting control and data signals, which corresponds to the fourth factor (Factor 4) of the factors to be considered when performing AGC in an NR V2X sidelink communication system discussed above.

[0133] In the case of DMRS for the data channel introduced in the NR UE to gNB link Uu a-30 and a-35, a pre-DMRS is introduced to position the DMRS in front of the data channel in the time domain to achieve fast channel estimation, thereby reducing the delay in data decoding. However, when the RS is included in the AGC establishment part, serious problems may occur in terms of reception performance because the RS cannot be used for channel estimation. For example, if the pre-DMRS is located at the first symbol of the data channel, and the first symbol of the data channel is used for AGC through method 2 disclosed above, the position of the pre-DMRS needs to be determined.

[0134] In this regard, the aforementioned method 1 is advantageous in that, by maintaining the time domain of the transmission control and data signals and inserting the preamble into the immediately preceding symbol, there is no need to further consider the positioning of the RS.

[0135] As described below, a method for configuring the location of RS in an NR V2X sidelink communication system is provided, and specifically, a method for configuring a gNB and a UE for DMRS is provided.

[0136] As mentioned above, the DMRS of the data channel introduced in the NR UE to gNB links Uu-a-30 and a-35 is designed to be configured in a flexible manner. Specifically, the configuration information about the DMRS pattern in the NR system can be as follows.

[0137] Based on the following five (5) pieces of information, DMRS information may be configured on a data channel in the NR Uu communication system.

[0138] 1. Depending on whether the corresponding DMRS mode is PDSCH or PUSCH mapping type A and type B, the DMRS position configuration including the position of the pre-DMRS will be different.

[0139] 2. Whether DMRS mode type 1 or type 2 is configured in RRC, where dmrs-Type∈{1,2}.

[0140] 3. Information indicating whether the preceding DMRS pattern is a single symbol pattern or an adjacent dual symbol pattern, which is configured in the RRC as information on the maximum length of the DMRS symbol, where DMRS-max-len∈{1,2}.

[0141] 4. An additional number of DMRS is configured in RRC, where DMRS-max-len∈{1,2}.

[0142] 5. The DMRS port number and the number of CDM groups are indicated through downlink control information (DCI).

[0143] The DMRS in the NR V2X sidelink communication system needs to be designed according to the characteristics of the sidelink. Specifically, D2D communication is performed using other vehicle UEs a-10, a-11, and a-12; a pedestrian portable UE A-15; and side links (PC5), a-20, a-21, a-22, and a-25. Therefore, unlike cellular communication using gNB a-01 and vehicle UE to gNB links Uu a-30 and a-35, there is no need to define two channels such as PDSCH and PUSCH. In addition, because the sidelink needs to be able to work even when the radio resource control is not connected, the method of configuring DMRS through RRC in the NR Uu communication system is not suitable. First, based on the method of configuring DMRS information for the data channel in the NR Uu communication system, the following five (5) DMRS design elements to be considered for NR sidelink communication are as follows.

[0144] 1. Method for configuring DMRS location.

[0145] 2. Methods for configuring DMRS modes (Type 1 and Type 2).

[0146] 3. A method for supporting multiple orthogonal DMRS ports.

[0147] 4. Method for configuring multiple additional DMRSs.

[0148] 5. A method for indicating a DMRS port number and multiple CDM groups.

[0149] A method based on the above considerations will be described below.

[0150] First, the method of configuring the position of DMRS in the NR side link using PUSCH mapping type A and type B in the NR Uu communication system is recovered. In the case of PDSCH mapping type B, when the scheduling symbol length is NCP, DMRS is designed only for 2 / 4 / 7. In the case of PUSCH mapping type B, DMRS positions of various symbol lengths are supported. Therefore, as a method of supporting physical sidelink shared channel (PSSCH) mapping types using PUSCH mapping type A and type B in the NR Uu communication system, as a method of configuring the DMRS position in the NR side link, there may be the following three (3) alternatives.

[0151] Alternative-1: Only PSSCH mapping type A is supported.

[0152] In case of PSSCH mapping type A, the reference point l of the position is defined from the first symbol of the slot. The DMRS positions in Table 4 below are used.

[0153] In Table 4, one of the following methods can be selected to determine l 0 The value of .

[0154] - Only supports l 0 =2

[0155] - Only supports l 0 =3

[0156] -Support 0 =2 or 3.

[0157] You can choose one of the following configuration methods to determine l 0 =2 or 3.

[0158] l 0 =2 or 3 is indicated by the sidelink control information.

[0159] l 0 =2 or 3 is indicated by the sidelink MIB (Master Information Block) or SIB (System Information Block).

[0160] - According to the resource pool configuration instructions 0 =2 or 3.

[0161] In the case of PSSCH mapping type A, the meaning of "symbol duration" in the following Table 4 represents the symbol duration between the first symbol of the time slot and the last symbol of the scheduled PSSCH.

[0162] Alternative-2: Only PSSCH mapping type B is supported.

[0163] In case of PSSCH mapping type B, the reference point l of the position is defined from the first symbol of the scheduled PSSCH.

[0164] If the above method 1 is used, the DMRS position is determined based on the following Table 5. In Table 5, l 0 The value is configured as l 0 =0.

[0165] If the above-mentioned method 2 is used, when inserting a preamble for AGC for one symbol, the DMRS position in Table 6 is used. Otherwise, the DMRS position in Table 5 is used.

[0166] For example, refer to Figure 1K, when the symbol length of the scheduled PSSCH is 7 and the number of additional DMRSs is configured as 1, the position of the DMRS disclosed in Table 6 is shown in k-02. For reference, k-01 represents the DMRS position of the existing PUSCH mapping type B in the same case.

[0167] In Table 6 below, 0 The value is configured as l 0 =0.

[0168] If the above-mentioned method 2 is used, when inserting the preamble for AGC for two symbols, the DMRS positions in the following Table 7 shall be used. Otherwise, the DMRS positions in Table 5 shall be used.

[0169] In Table 7, l 0 The value is configured as l 0 =2.

[0170] In case of PSSCH mapping type B, the meaning of "duration in symbol" in Tables 5, 6 and 7 indicates the symbol duration of the scheduled PSSCH.

[0171] Alternative-3: Support PSSCH mapping type A and type b.

[0172] If both types (Type A and Type B) are supported, the DMRS positions given in Alternative-1 and Alternative-2 may be used, and reference may be made to the DMRS position configuration method described in Alternative-1 and Alternative-2.

[0173] To support both types, if the DMRS pattern is type A or type B, it can be indicated by SCI. If the DMRS pattern is type A or type B, it may be indicated by the sidelink MIB or SIB. If the DMRS pattern is type A or type B, it can be indicated according to the resource pool configuration.

[0174] Table 4

[0175]

[0176] Table 5

[0177]

[0178] Table 6

[0179]

[0180] Table 7

[0181]

[0182] Even when the above-mentioned method 1 or method 2 is not used, that is, even when the preamble code for AGC is not introduced, the above-mentioned Table 4 and Table 5 can also be used to locate the DMRS of the NR side link.

[0183] Next, since the DMRS pattern (type 1 and type 2) in the NR side link is considered, the DMRS pattern (type 1 and type 2) in the NR Uu communication system can be considered. In addition, the number of orthogonal DMRS ports supported in the NR side link should be considered together to determine the DMRS pattern. Considering the mobile speed, it is generally difficult to support a higher level in the side link environment compared to the Uu communication environment. Therefore, as Figure 1D As described in , the dual symbol mode for supporting multiple orthogonal DMRS ports can be excluded from consideration. Therefore, in Tables 4, 5, 6 and 7, only the DMRS position configuration in the case of supporting the single symbol mode is considered. In addition, as a method of configuring the DMRS mode (type 1 and type 2) in the NR side link, the following three (3) options are possible.

[0184] Alternative-1: DMRS pattern type 1 only, e.g. Figure 1D The pattern is d-10.

[0185] Alternative-2: DMRS pattern type 2 only, e.g. Figure 1D Mode d-30.

[0186] Alternative 3: Support DMRS pattern type 1 and type 2. In this case, to support both types, the DMRS pattern may be type 1 or type 2 indicated by the SCI; the DMRS pattern may be type 1 or type 2 indicated by the sidelink type MIB or SIB; or the DMRS pattern may be type 1 or type 2 indicated according to the resource pool configuration.

[0187] Depending on the maximum number of orthogonal DMRS ports supported by the NR side link, the method of indicating or not indicating the NR side link DMRS port number and the number of CDM groups.

[0188] Unlike the NR Uu communication system, even without an RRC connection, it should be possible to indicate the method for configuring the number of additional DMRS (dmrs-Additional∈{0, 1, 2, 3}) in the NR side link. Therefore, the number of additional DMRS can be indicated by SCI; the number of additional DMRS can be indicated by side MIB or SIB; or the number of additional DMRS can be indicated according to the resource pool configuration.

[0189] Therefore, the method and parameter configuration method of mainly configuring the DMRS position of the data channel have been described, but the structure of the DMRS is not limited to the data channel. Specifically, the same DMRS pattern and position configuration as the data channel can be applied to the control channel of the NR V2X side link. In addition, even when the DMRS structure of the control channel of the NR V2X side link is designed differently, if the first symbol of the control channel is used for AGC by the aforementioned method 2, the DMRS of the control channel should not be located in the first symbol of the control channel. In addition, even when other reference signals for the NR V2X side link including DMRS are introduced, if the first symbol of the control channel is used for AGC by the aforementioned method 2, the symbol should be restricted so that the RS is not sent in the symbol. For example, even when the channel state information RS (CSI-RS) for the NR V2X side link is introduced, it is necessary to force the RS not to be sent at the symbol position used for AGC.

[0190] According to an embodiment, a method is provided in which a transmitting UE generates a DMRS sequence for a PSSCH in a side link and sends the generated DMRS sequence to a receiving UE. In addition, the receiving UE receives the DMRS sequence. In the side link, the receiving UE assumes that the following sequence in equation (1) is used to send the DMRS.

[0191]

[0192] Here, r(n) represents a reference signal sequence and is defined in 38.211, and c() represents a pseudo-random sequence and is defined in Section 5.2.1 of 38.211. The pseudo-random sequence can be initialized according to equation (2).

[0193]

[0194] Here, l represents the OFDM symbol number in the time slot, Indicates the time slot number in the frame. In the side link, assume that n SCID = 0 and This can be assumed in the following five (5) ways.

[0195] Method 1 is the decimal of PSCCH CRC. Here, is satisfied. For the values ​​of p and L, see 5.1 of TS38.212.

[0196] Method 2 is the target ID. Here, assuming It is the target ID value in SCI.

[0197] Method 3 is source ID. Here, assume It is the source ID value in SCI.

[0198] Method 4 is the side link synchronization ID. Here, it is assumed that Sidelink synchronization ID The sidelink synchronization ID is an ID used when synchronizing in the sidelink.

[0199] Method 5 is a combination of methods 1 to 4 above. If the number of bits used in methods 1 to 4 is 16 bits or less, when the number of bits When the number does not exceed 16 bits, even in the combination of different methods, different combinations of methods can be considered. For example, in the case of a combination of method 2 (target ID) and method 3 (source ID), assuming that the target ID is 4 bits of information and the source ID is also 4 bits of information, it can be determined by a combination of target ID + source ID or source ID + target ID. Through such a combination, it is possible to further randomize the DMRS sequence.

[0200] In the above method, if the number of digits in methods 1 to 5 is If the DMRS does not exceed 16 bits, the following bits can be considered to be filled with zeros. If one of the above methods is used, the UE can assume this and receive the DMRS for the PSSCH.

[0201] According to an embodiment, a method is provided in which a transmitting UE indicates information about a DMRS port for a PSSCH in a sidelink. Specifically, the signaling information may be determined by the following four (4) conditions.

[0202] Condition 1 is the maximum number of orthogonal DMRS ports for single-user MIMO (SU-MIMO) supported by each UE. A method of indicating the DMRS ports may differ depending on Condition 1.

[0203] Condition 2 is the maximum orthogonal DMRS port of multi-user MIMO (MU-MIMO) supported by each UE. The method of indicating the DMRS port may differ depending on Condition 2.

[0204] Condition 3 is the used DMRS configuration type. The method of indicating the DMRS port may vary depending on condition 3. In this case, for example, DMRS pattern type 1 or DMRS pattern type 2 may be used as the DMRS configuration type of condition 3. However, the embodiments of the present disclosure are not limited thereto. The number of patterns to be used may vary. For example, DMRS pattern type 1 may refer to reference Figure 1D Description of 1d-10.

[0205] In addition, DMRS mode type 2 can refer to Figure 1DHowever, mode types 1 and 2 are not limited to 1d-10 and 1d-20, and various DMRS patterns (e.g., patterns configured or predefined by the gNB) may be used. Alternatively, it may be assumed that reference Figure 1D A symbol pattern in the DMRS pattern described.

[0206] Condition 4 is whether to indicate the number of DMRS CDM groups. The method of indicating the DMRS port may vary depending on condition 4. If the number of CDM groups is 1, it can be assumed that the ratio of the energy per resource element (EPRE) of PSSCH to DMRS EPRE is a predetermined value or a configured value (e.g., 0 dB). If the number of CDM groups is 2, it can be assumed that the ratio of PSSCH EPRE to DMRS EPRE is a predetermined value or a configured value (e.g., -3 dB). If the number of CDM groups is 3, it can be assumed that the ratio of PSSCH EPRE to DMRS EPRE is a predetermined value or a configured value (e.g., -4.77 dB). In addition, if the number of DMRS CDM groups is indicated, the receiving UE can simulate MU interference when MU-MIMO is supported.

[0207] In this case, the information for indicating the DMRS port may be determined based on at least one of the above conditions 1 to 4. An example of a specific method for indicating the DMRS port is as follows.

[0208] When the conditions are condition 1 (2 ports) + condition 2 (1 port) + condition 3 (type 2) + condition 4 (indication), as a method of indicating the DMRS port, the following Table 8 can indicate the SCI, and thus can indicate DMRS port related information (for example, DMRS port number, the number of DMRS ports, and the number of CDM groups).

[0209] Table 8

[0210] value Number of DMRS CDM groups without data DMRS Port 0 1 0 1 1 1 2 2 0 3 2 1 4 2 2 5 2 3 6 3 0 7 3 1 8 3 2 9 3 3 10 3 4 11 3 5 12 1 0，1 13 2 0，1 14 3 0，1 15 Reserve Reserve

[0211] When the conditions are condition 1 (2 ports) + condition 2 (0 ports) + condition 3 (type 2) + condition 4 (indication), as a method of indicating a DMRS port, the following Table 9 can indicate SCI, and thus can indicate DMRS port related information.

[0212] Table 9

[0213] value Number of DMRS CDM groups without data DMRS Port 0 1 0 1 2 0 2 3 0 3 1 0，1 4 2 0，1 5 3 0，1 6-7 Reserve Reserve

[0214] When the conditions are condition 1 (2 ports) + condition 2 (1 port) + condition 3 (type 2) + condition 4 (not indicated), as a method of indicating a DMRS port, the following Table 10 can indicate SCI, and thus can indicate DMRS port related information.

[0215] Table 10

[0216] value DMRS Port 0 0 1 1 2 2 3 3 4 4 5 5 6 0，1 7 Reserve

[0217] When the conditions are condition 1 (2 ports) + condition 2 (0 ports) + condition 3 (type 2) + condition 4 (not indicated), as a method of indicating a DMRS port, the following Table 11 can indicate SCI, and thus can indicate DMRS port related information.

[0218] Table 11

[0219] value DMRS Port 0 0 1 0，1

[0220] When the conditions are condition 1 (4 ports) + condition 2 (2 ports) + condition 3 (type 2) + condition 4 (indication), as a method of indicating a DMRS port, the following Table 12-1 can indicate SCI, and thus can indicate DMRS port related information.

[0221] Table 12-1

[0222] value Number of DMRS CDM groups without data DMRS Port 0 1 0 1 1 1 2 1 0，1 3 2 0 4 2 1 5 2 2 6 2 3 7 2 0，1 8 2 2，3 9 2 0-2 10 2 0-3 11 3 0 12 3 1 13 3 2 14 3 3 15 3 0，1 16 3 2，3 17 3 0-3 18-31 Reserve Reserve

[0223] By reducing unnecessary signaling in Table 12-1, a 4-bit table can be used as shown in Table 12-2 below.

[0224] Table 12-2

[0225] value Number of DMRS CDM groups without data DMRS Port 0 1 0 1 1 1 2 1 0，1 3 2 0 4 2 1 5 2 2 6 2 3 7 2 0，1 8 2 2，3 9 2 0-2 10 2 0-3 11 3 0 12 3 1 13 3 2 14 3 3 15 3 0-3

[0226] When the conditions are condition 1 (4 ports) + condition 2 (1 port) + condition 3 (type 2) + condition 4 (indication), as a method of indicating a DMRS port, the following Table 13 can indicate SCI, and thus can indicate DMRS port related information.

[0227] Table 13

[0228] value Number of DMRS CDM groups without data DMRS Port 0 1 0 1 1 1 2 1 0，1 3 2 0 4 2 1 5 2 2 6 2 3 7 2 0-2 8 2 0-3 9 3 0 10 3 1 11 3 2 12 3 3 13 3 0-3 14-15 Reserve Reserve

[0229] When the conditions are condition 1 (4 ports) + condition 2 (2 ports) + condition 3 (type 2) + condition 4 (not indicated), as a method of indicating a DMRS port, the following Table 14 can indicate SCI, and thus can indicate DMRS port related information.

[0230] Table 14

[0231] value DMRS Port 0 0 1 1 2 2 3 3 4 0，1 5 2，3 6 0-2 7 0-3

[0232] When the conditions are condition 1 (4 ports) + condition 2 (1 port) + condition 3 (type 2) + condition 4 (not indicated), as a method of indicating a DMRS port, the following Table 15 can indicate SCI, and thus can indicate DMRS port related information.

[0233] Table 15

[0234] value DMRS Port 0 0 1 1 2 2 3 3 4 0-2 5 0-3 6-7 Reserve

[0235] When the conditions are condition 1 (2 ports) + condition 2 (1 port) + condition 3 (type 1) + condition 4 (indication), as a method of indicating a DMRS port, the following Table 16 can indicate SCI, and thus can indicate DMRS port related information.

[0236] Table 16

[0237] value Number of DMRS CDM groups without data DMRS Port 0 1 0 1 1 1 2 1 0，1 3 2 0 4 2 1 5 2 0，1 6-7 Reserve Reserve

[0238] When the conditions are condition 1 (2 ports) + condition 2 (0 ports) + condition 3 (type 1) + condition 4 (indication), as a method of indicating a DMRS port, the following Table 17 can indicate SCI, and thus can indicate DMRS port related information.

[0239] Table 17

[0240] value Number of DMRS CDM groups without data DMRS Port 0 1 0 1 1 0，1 2 2 0 3 2 0，1

[0241] When the conditions are condition 1 (2 ports) + condition 2 (1 port) + condition 3 (type 1) + condition 4 (not indicated), as a method of indicating a DMRS port, the following Table 18 can indicate SCI, and thus can indicate DMRS port related information.

[0242] Table 18

[0243] value DMRS Port 0 0 1 1 2 0，1 3 Reserve

[0244] When the conditions are condition 1 (2 ports) + condition 2 (0 ports) + condition 3 (type 1) + condition 4 (not indicated), as a method of indicating a DMRS port, the following Table 19 can indicate SCI, and thus can indicate DMRS port related information.

[0245] Table 19

[0246] value DMRS Port 0 0 1 0，1

[0247] When the conditions are condition 1 (4 ports) + condition 2 (2 ports) + condition 3 (type 1) + condition 4 (indication), as a method of indicating a DMRS port, the following Table 20 can indicate SCI, and thus can indicate DMRS port related information.

[0248] Table 20

[0249] value Number of DMRS CDM groups without data DMRS Port 0 1 0 1 1 1 2 1 0，1 3 2 0 4 2 1 5 2 2 6 2 3 7 2 0，1 8 2 2，3 9 2 0-2 10 2 0-3 11-15 Reserve Reserve

[0250] When the conditions are condition 1 (4 ports) + condition 2 (1 port) + condition 3 (type 1) + condition 4 (indication), as a method of indicating a DMRS port, the following Table 21 can indicate SCI, and thus can indicate DMRS port related information.

[0251] Table 21

[0252] value Number of DMRS CDM groups without data DMRS Port 0 1 0 1 1 1 2 1 0，1 3 2 0 4 2 1 5 2 2 6 2 3 7 2 0，1 8 2 0-2 9 2 0-3 10-15 Reserve Reserve

[0253] When the conditions are condition 1 (4 ports) + condition 2 (2 ports) + condition 3 (type 1) + condition 4 (not indicated), as a method of indicating a DMRS port, the following Table 22 can indicate SCI, and thus can indicate DMRS port related information.

[0254] Table 22

[0255] value DMRS Port 0 0 1 1 2 2 3 3 4 0，1 5 2，3 6 0-2 7 0-3

[0256] When the conditions are condition 1 (4 ports) + condition 2 (1 port) + condition 3 (type 1) + condition 4 (not indicated), as a method of indicating a DMRS port, the following Table 23 can indicate SCI, and thus can indicate DMRS port related information.

[0257] Table 23

[0258] value DMRS Port 0 0 1 1 2 2 3 3 4 0，1 5 0-2 6 0-3 7 Reserve

[0259] The method for indicating the DMRS port information of the PSSCH disclosed in this embodiment is distinguished from the method in the existing communication system based on at least one of the following: whether the maximum number of orthogonal DMRS ports to be supported by SU-MIMO of each UE supported in the side link is supported; whether the maximum number of orthogonal DMRS ports to be supported by MU-MIMO of each UE is supported; whether the type of DMRS configuration used is supported; and whether the number of DMRS CDM groups is supported. In addition, a method of minimizing unnecessary signaling can be used to minimize signaling overhead. Moreover, the index order can be modified for each signaling table.

[0260] According to an embodiment, an additional method of inserting a preamble code according to the subcarrier spacing is provided. As described above, a method of configuring a preamble code has been disclosed below so as to effectively perform AGC in an NR sidelink communication system.

[0261] As described above, for the subcarrier spacing corresponding to 15KHz / 30KHz, no preamble is inserted. For the subcarrier spacing corresponding to 60KHz, a preamble of a single symbol length is inserted. For the subcarrier spacing corresponding to 120KHz, considering the preamble overhead, a preamble of two symbol lengths may be inserted in the same manner as for 60KHz, or a preamble of a single symbol length may be inserted.

[0262] Therefore, it is assumed that the time interval required for AGC is 15usec. However, since an increased time interval may be required, an example of a method of configuring a preamble in another time interval will be described below.

[0263] According to the first method, for the subcarrier spacing corresponding to 15KHz, no preamble is inserted. For the subcarrier spacing corresponding to 30KHz, a preamble of a single symbol length is inserted. For the subcarrier spacing corresponding to 60KHz and 120KHz, a preamble of two symbol lengths is inserted. This method is disclosed under the assumption that the time interval required for AGC is required to be 35usec for all subcarrier spacings.

[0264] According to the second method, for subcarrier spacings corresponding to 15 kHz and 30 kHz, a preamble of a single symbol length is inserted. For subcarrier spacings corresponding to 60 kHz and 120 kHz, a preamble of two symbols length is inserted.

[0265] In the second method, the preamble is always sent in the AGC region. When using this method, it may be helpful to perform sensing in a mode where the UE directly performs sensing in the sidelink to select resources, such as listen before talk (LBT).

[0266] More specifically, since the preamble is always sent in the AGC region, the UE can determine whether the corresponding channel is idle or busy by performing energy detection on the preamble in the region. In this case, when the channel is idle, it is determined that the channel is not occupied by another UE. When the channel is busy, it is determined that the channel is occupied by another UE.

[0267] When the preamble is transmitted in the AGC region by the second method, it means that the control information and data are transmitted in the next time slot. In contrast, according to the above method 2, the control information and data are transmitted in the corresponding time slot. Therefore, when the second method is used, it may be very important to select resources by performing sensing in the side link.

[0268] The preamble refers to a signal transmitted by a UE transmitting a control and data signal so that the UE receiving the control and data signal performs AGC. The method of inserting a preamble (preamble length and positioning) according to the subcarrier spacing is not limited to the above method.

[0269] In order to implement the above embodiments of the present disclosure, Figure 1L and Figure 1M The transmitter, receiver and processor of each of the UE and gNB are shown respectively.

[0270] In order to perform the method of performing AGC and the reference signal configuration method in the V2X system, the receiver, processor and transmitter of the gNB and the UE should operate according to the above embodiments.

[0271] Specifically, Figure 1L is a block diagram illustrating an internal structure of a UE according to an embodiment.

[0272] like Figure 1L As shown, the UE includes a UE receiver 1800 , a UE transmitter 1804 and a UE processor 1802 .

[0273] The UE receiver 1800 and the UE transmitter 1804 may be collectively referred to as a transceiver. The transceiver may send and receive signals to and from the gNB. The signal may include control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal and an RF receiver for low-noise amplifying the received signal and down-converting the frequency. In addition, the transceiver may receive a signal through a wireless channel, output the signal to the UE processor 1802, and transmit a signal output from the UE processor 1802 through a wireless channel.

[0274] According to the above-described embodiments of the present disclosure, the UE processor 1802 may control a series of processes to operate the UE. The UE processor 1802 may be referred to as a controller, and the controller may be defined as a circuit, an application specific integrated circuit (ASIC), or at least one processor.

[0275] Figure 1M is a block diagram showing the internal structure of a gNB according to an embodiment.

[0276] like Figure 1M As shown, the gNB of the present disclosure may include a gNB receiver 1901, a gNB transmitter 1905 and a gNB processor 1903.

[0277] The gNB receiver 1901 and the gNB transmitter 1905 are collectively referred to as a transceiver. The transceiver can send and receive signals to and from the UE. The signal may include control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal and an RF receiver for low-noise amplification and down-converting the received signal. In addition, the transceiver may receive a signal through a wireless channel, may output a signal to the gNB processor 1903, and may send a signal output from the gNB processor 1903 through a wireless channel.

[0278] The gNB processor 1903 can control a series of processes to operate the gNB. The gNB processor 1903 can be called a controller, and the controller can be defined as a circuit, an ASIC, or at least one processor.

[0279] Another embodiment of the present disclosure describes a method for determining an AGC in a side link, a transmission position of a PSCCH according to the AGC, and a DMRS transmission position of a PSSCH. Figure 1H As described above, a symbol region for AGC may be required before sending control and data information in the sidelink. For the transmission position of PSCCH in the sidelink, the following alternatives may be considered.

[0280] *Alternative 1: PSCCH is located at the first sidelink symbol of the slot

[0281] *Alternative 2: PSCCH is located at the second sidelink symbol of the slot

[0282] *Alternative 3: PSCCH is located at the third sidelink symbol of the slot

[0283] In the above description, "sidelink symbol" refers to a symbol used as a sidelink in a time slot. Note that all symbols in a time slot can be used for sidelink transmission, and only part of the time slot can be used for sidelink transmission. In the present disclosure, it is specified that the position in time assumed by the sidelink transmission is determined based on the sidelink symbol. In addition, the symbol length of the PSCCH can be pre-configured for each TX / RX resource pool. For example, X∈{2,3} can be configured as the possible length of X. In addition, the position of the PSCCH in the frequency can be only in the frequency where the PSSCH is such as Figure 2The PSSCH is transmitted in one of the scheduled subchannels shown, and can be mapped and transmitted starting from the lowest PRB in frequency. The starting position of the subchannel (startRB-Subchannel, 2-11), the size of the subchannel (sizeSubchannel, 2-12), and the number of subchannels (numSubchannel, 2-13) can be configured in the resource pool. The length LsubCH (2-14) to which the PSSCH is allocated can be determined in frequency in the configured resource pool information. Figure 2 A case is shown where four subchannels are allocated to the PSSCH starting from the third subchannel based on a low subchannel in the frequency of the subchannels configured as a resource pool. In this case, an example is shown in which the PSCCH is mapped from the lowest PRB in the frequency in an area where the PSCCH is allocated and transmitted in one subchannel. This embodiment describes a method for determining the DMRS transmission position of the PSSCH for the above three alternatives. Please note that the present disclosure is not limited to the DMRS positions given below. Even if the detailed position of transmitting the DMRS changes, according to the UE speed limited by the present disclosure, the configured number of DMRS symbols, and the number of subchannels allocated to the PSSCH, the method for determining the transmission position of the DMRS can be applied regardless of the detailed DMRS position.

[0284] First, alternative 1 is a method in which the symbol region used for AGC is not considered separately in the case where the PSCCH is located in the first sidelink symbol of the slot. An example of the PSCCH location of alternative 1 is as follows Figure 3A 3-20 in . Therefore, when the corresponding method is used, there is a disadvantage that the PSCCH reception performance may be degraded. However, considering this method, when the symbol length of the PSCCH is 3 or less, the PDCCH DMRS transmission position in the NR Uu system can be reused as is. More specifically, a method for supporting a DMRS mode for PSSCH will be described below.

[0285] [Method for supporting DMRS pattern in time for PSSCH]

[0286] In the following Tables 24 and 25, the location of the DMRS is based on the first symbol for the side link.

[0287] *The DMRS pattern for PSSCH is defined as single-symbol DMRS.

[0288] **In d-10 and d-30, two frequency modes of PSSCH single-symbol DMRS are shown. DMRS Type A (d-10) is a type that supports up to four orthogonal DMRS ports and has a cyclic shift (CS) length 2 structure in a Comb 2 structure. DMRS Type B (d-30) is a structure in which an orthogonal cover code (OCC) is applied to two REs near the frequency axis and FDM is applied to support up to six orthogonal DMRS ports. Both modes can be used in the side link, or only one of the two mode types can be selected and supported. If both modes are supported, the configuration of the two modes can be pre-configured in the resource pool. Alternatively, it can be dynamically indicated by SCI.

[0289] * A DMRS pattern in time for PSSCH may be determined by a method in which a single-symbol DMRS is transmitted in a symbol interval in which PSSCH is transmitted, and whether a single fixed DMRS pattern is used for resource pool configuration or multiple DMRS patterns in time are used may be pre-configured.

[0290] **If a fixed DMRS pattern is configured for resource pool configuration, considering the high-speed transmission environment of the side link, the DMRS pattern in time in the PSSCH region can be determined as a DMRS pattern corresponding to dmrs-AdditionalPosition = 3 by "Duration in the side link symbol" based on Table 24. If dmrs-AdditionalPosition is 0, 1, 2, and 3, it means that DMRS is sent with 1, 2, 3, and 4 symbols, respectively.

[0291] **If multiple DMRS modes are used for resource pool configuration, the UE can select the corresponding mode. In addition, the information of the selected mode can be notified to other UEs through SCI. In this case, based on Table 24, the optional DMRS mode in time can be "dmrs-AdditionalPosition". According to Table 24, the actual DMRS mode transmitted in time is determined by the "duration of the side link symbol" and the selected "dmrs-AdditionalPosition".

[0292] Table 24

[0293]

[0294] In Table 24, l o The value of may be used as a fixed value, or may be determined according to the PSCCH symbol length. o The value of is fixed, then l oIt may be 3. In contrast, when l is determined based on the PSCCH symbol length o When the value of o The value of can be pre-configured in the resource pool as 2 or 3. In contrast, if the PSCCH symbol length of the configured resource pool is 2, then l o The value of is determined to be 2, or if the PSCCH symbol length of the configured resource pool is 3, then l o The value of is determined to be 3. Figure 3B 3-50 in FIG. 24 shows an example, wherein according to Table 241 o The value of is configured as 2 and four DMRS symbols are transmitted. Figure 3B middle, Figure 3B 3-60 of FIG. 241 show the o An example in which the value of is configured as 3 and four DMRS symbols are transmitted.

[0295] Next, alternative 2 is one in which a symbol region method for AGC is considered in the case where the PSCCH is located in the second sidelink symbol of the slot. Figure 3A In the example of the PSCCH position of alternative 2, 3-30 is shown. At this time, for the use of the first side link symbol, the following method can be considered.

[0296] *Method 1: Send PSSCH

[0297] *Method 2: Send preamble for AGC

[0298] * Method 3: Copy and send the PSCCH transmitted in the second sidelink symbol

[0299] In the case of alternative 2, unlike alternative 1, the PDCCH DMRS transmission position in the NR Uu system cannot be reused as it is. Specifically, since the first symbol of the side link is considered to be a symbol of AGC, when the PSCCH has a maximum length of three symbols, the first PSSCH DMRS position should be located after the PSCCH symbol. More specifically, even when method 1 is used, the PSSCH DMRS cannot be sent in the first symbol of the side link. This is because, when the PSSCH DMRS is sent to a symbol area used in consideration of AGC, distortion may occur in DMRS channel estimation, and thus the PSSCH decoding performance may be reduced. Therefore, when alternative 2 is considered, in the above-mentioned method of supporting the DMRS pattern in time for PSSCH, the following Table 25 can be used instead of Table 24. However, the disclosure is not limited to the DMRS positions of Table 25.

[0300] Table 25

[0301]

[0302] In Table 25, l o The value of may be used as a fixed value, or may be determined according to the PSCCH symbol length. o The value of is fixed, then l o It may be 4. In contrast, when l is determined based on the PSCCH symbol length, o When the value of o The value of can be pre-configured as 3 or 4 in the resource pool. In contrast, when the PSCCH symbol length of the configured resource pool is 2, l o The value is determined to be 3. When the PSCCH symbol length of the configured resource pool is 3, l o The value of is determined to be 4. Figure 3C 3-70 in FIG. 25 shows an example, wherein according to Table 251 o The value of is configured as 4 and two DMRS symbols are transmitted. Figure 3C 3-80 in FIG. 25 shows an example, wherein according to Table 251 o The value of is configured to be 4 and four DMRS symbols are transmitted. However, considering only the case where the PSCCH DMRS is always transmitted after the region where the PSCCH is transmitted in time, compared to alternative 1, in alternative 2, the last symbol of the PSCCH is pushed back by one symbol, and therefore, if the channel changes rapidly over time, the accuracy of the channel estimation of the PSCCH located in the front region of the first PSCCH DMRS may be reduced. Therefore, when one or more of the following conditions are met, the PSSCH DMRS may overlap with the region where the PSCCH is transmitted in time, and may be transmitted in another frequency domain. In the present disclosure, the following conditions are not limited to alternative 2.

[0303] [Condition that the PSSCH DMRS symbol overlaps with the region of the PSCCH at the transmission time and is transmitted in another frequency domain]

[0304] *Condition 1: UE speed (absolute speed of TX UE or relative speed between TX / RX UE) is greater than or equal to A

[0305] *Condition 2: The number of configured DMRS symbols is greater than or equal to B

[0306] *Condition 3: The number of subchannels allocated by PSSCH is greater than or equal to C

[0307] First, condition 1 may be a valid condition because the channel changes rapidly over time when the UE speed is high. For example, when the corresponding speed is A km / h or higher, the corresponding condition may be established. Next, condition 2 may be a valid condition because a large number of DMRS symbols are configured when the channel changes rapidly over time. For example, when the number of DMRS symbols is configured to be 4 (when dmrs-AdditionalPosition=3 in Table 24 and Table 25), the corresponding condition may be established. In addition, since the PSSCH area located in the front area of ​​the first PSSCH DMRS increases with the increase in the number of subchannels allocated by the PSSCH, the corresponding condition may be a valid condition. For example, when the number of subchannels allocated by the PSSCH is C or more, the corresponding condition may be established. However, the present disclosure is not limited to the above conditions. In addition, when one or more of the above conditions are met, a method of allowing the PSSCH DMRS to overlap with the area where the PSCCH is transmitted in time and to be transmitted in other frequency domains may be considered. For example, if condition 2 and condition 3 are met at the same time, this method may be used. Figure 3D 3-90 and 3-100 in FIG. 3 show two methods of sending PSCCH DMRS before sending PSCCH in the time domain. First, as Figure 3D As shown in 3-90 of FIG. 1 , as a first method, it is shown that l o The first method is a method of allowing PSSCH DMRS to be transmitted in all frequency domains where PSCCH is not transmitted when PSSCH DMRS overlaps with the region where PSCCH is transmitted in time and is transmitted in other frequency domains. Specifically, Figure 3D As shown in 3-90 of FIG. 1 , even when the PSCCH is mapped to all PRBs and is not transmitted in one subchannel, the PSSCH DMRS overlaps with the region where the PSCCH is transmitted in the remaining frequency domain. In contrast, as a second method, Figure 3D 3-100 in FIG. 25 shows that according to Table 25, l 0 The value of is configured as 2 and four DMRS symbols are transmitted. The second method is a method in which, when the PSSCH DMRS overlaps with the area of ​​the PSCCH at the transmission time and is transmitted in other frequency domains, the PSSCH DMRS is allowed to be transmitted in all frequency domains of another subchannel in which the PSCCH is not transmitted.

[0308] In Table 24 and Table 25, a method has been described in which the first DMRS symbol (pre-DMRS) of the PSSCH DMRS is determined based on the first symbol used in the side link. o, and fixed or configured according to the PSCCH symbol length l o At this time, considering the PSCCH symbol length, the first DMRS symbol l of the PSCCH DMRS o The position of the PSSCH DMRS may be fixed or configured to always be located after the PSCCH symbol. Different from this, the first DMRS symbol l of the PSSCH DMRS may be determined in such a way that o The position of the PSSCH DMRS symbol is such that the PSSCH DMRS symbol overlaps with the region of the PSCCH at the transmission time and is transmitted in other frequency domains. In addition, as described above, only when one or more of the above conditions are met, the PSSCH DMRS symbol may be allowed to overlap with the region of the PSCCH at the transmission time and be transmitted in other frequency domains. o The position of the next DMRS symbol, if the PSCCH DMRS symbol overlaps with the area of ​​the PSCCH at the transmission time and is transmitted in other frequency domains, one or more PSCCH DMRS symbols may overlap with the area of ​​the PSCCH at the transmission time. It may overlap with the area of ​​the PSCCH at the transmission time. Note that the present disclosure is not limited to the PSSCH DMRS position configuration method in Tables X and Y. Generally, the PSSCH DMRS symbol position can be determined to always be located after the PSCCH in time. Alternatively, the PSSCH DMRS symbol position may overlap with the area of ​​the PSCCH at the transmission time and may be configured in other frequency domains. In the latter case, the following three methods can be considered.

[0309] *PSSCH DMRS transmission in overlapping areas is not allowed, and puncturing (or rate matching) is performed on the PSSCH DMRS in the corresponding areas.

[0310] *PSSCH DMRS transmission in overlapping areas is allowed, and PSSCH DMRS is sent.

[0311] *When the proposed condition [PSSCH DMRS symbol overlaps with the region of PSCCH at the transmission time and is transmitted in other frequency domains] is met, PSSCH DMRS transmission of the overlapping region is allowed.

[0312] Finally, for alternative 3, if the PSCCH is located in the third sidelink symbol of the slot, one or two symbol regions for AGC can be considered. First, assuming one symbol region for AGC, the location example of alternative 3 is as follows Figure 3E3-110 in . However, unlike alternative 2, it can be considered that the PSSCH can be sent in the first side link symbol and the PSSCH DMRS can be sent in the second side link symbol. Figure 3E The reason why the PSSCH DMRS shown in 3-110 is considered to be transmitted in the second side link symbol is because the PSSCH is transmitted in the first side link symbol, and therefore, in the case where the channel changes rapidly over time, when the PSSCH DMRS is located after the PSCCH symbol in time, the channel estimation performance may degrade. However, in alternative 3, the following conditions can be considered as conditions for transmitting the PSSCH DMRS in the second side link symbol.

[0313] [Condition: In alternative 3 PSSCH DMRS is transmitted in the second sidelink symbol]

[0314] *Condition 1: UE speed (absolute speed of TX UE or relative speed between TX / RX UE) is greater than or equal to A

[0315] *Condition 2: The number of configured DMRS symbols is greater than or equal to B

[0316] *Condition 3: The number of subchannels allocated by PSSCH is greater than or equal to C

[0317] Specifically, the PSSCH DMRS may be sent in the second sidelink symbol only when one or more of the above conditions are met. Figure 3E As shown in 3-120, the PSSCH DMRS is sent after the PSCCH region in time. Figure 3E In the case of 3-120, two symbol regions can be considered for AGC.

[0318] In the above-described embodiments, according to the detailed embodiments presented, the components included in the present disclosure are expressed in the singular or plural. However, the singular form or plural form is selected to facilitate the description suitable for the presented situation, and the various embodiments of the present disclosure are not limited to its single element or multiple elements. In addition, multiple elements expressed in the specification can be configured as a single element, or a single element in the specification can be configured as multiple elements. In addition, an element expressed in plural form can be configured in singular form, or an element expressed in singular form can be configured in plural form.

[0319] On the other hand, in the drawings illustrating the method of the present disclosure, the order of description does not necessarily correspond to the order of execution, and the relationship of the front and the back may be changed or executed in parallel.

[0320] Optionally, the drawings illustrating the method of the present disclosure may include some additional components or omit some components within the scope that does not impair the nature of the present disclosure.

[0321] While the invention has been particularly shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims

1. A method performed by a first terminal in a wireless communication system, the method include: Generate a sequence of a demodulation reference signal DMRS for a physical side link shared channel PSSCH based on a pseudo random sequence; as well as sending the DMRS for the PSSCH to a second terminal, The pseudo-random sequence is initialized based on a cyclic redundancy check CRC on a physical side link control channel PSCCH, Wherein, the pseudo-random sequence is initialized as follows: in, Generate as follows: and Among them, the n SCID is a fixed value, and the fixed value is 0, in, represents the time slot number in the frame, l represents the OFDM symbol number in the time slot, in, represents the number of symbols per time slot, in, Indicates the decimal value of PSCCH CRC. Among them, p i represents the check digit, and Wherein, L represents the number of check bits.

2. The method according to claim 1, in, The pseudo-random sequence is initialized based on a decimal representation of the CRC on the PSCCH.

3. The method according to claim 1, in, The pseudo-random sequence is initialized based on a scrambling identifier.

4. A method performed by a second terminal in a wireless communication system, the method include: receiving a demodulation reference signal DMRS for a physical side link shared channel PSSCH from a first terminal, The sequence of the DMRS for the PSSCH is generated based on a pseudo-random sequence, and Wherein, the pseudo-random sequence is initialized based on a cyclic redundancy check CRC on a physical side link control channel PSCCH, Wherein, the pseudo-random sequence is initialized as follows: in, Generate as follows: and Among them, the n SCID is a fixed value, and the fixed value is 0, in, represents the time slot number in the frame, l represents the OFDM symbol number in the time slot, in, represents the number of symbols per time slot, in, Indicates the decimal value of PSCCH CRC. Among them, p i represents the check digit, and Wherein, L represents the number of check bits.

5. The method according to claim 4, in, The pseudo-random sequence is initialized based on a decimal representation of the CRC on the PSCCH.

6. The method according to claim 4, in, The pseudo-random sequence is initialized based on the scrambling identifier.

7. A first terminal in a wireless communication system, wherein the first terminal include: a transceiver configured to communicate with other network entities; as well as A controller, the controller being configured to: Generate a demodulation reference signal DMRS sequence for a physical side link shared channel PSSCH based on a pseudo-random sequence, and sending the DMRS for the PSSCH to a second terminal, The pseudo-random sequence is initialized based on a cyclic redundancy check CRC on a physical side link control channel PSCCH, Wherein, the pseudo-random sequence is initialized as follows: in, Generate as follows: and Among them, the n SCID is a fixed value, and the fixed value is 0, in, represents the time slot number in the frame, l represents the OFDM symbol number in the time slot, in, represents the number of symbols per time slot, in, Indicates the decimal value of PSCCH CRC. Among them, p i represents the check digit, and Wherein, L represents the number of check bits.

8. The first terminal according to claim 7, in, The pseudo-random sequence is initialized based on a decimal representation of the CRC on the PSCCH.

9. The first terminal according to claim 7, in, The pseudo-random sequence is initialized based on a scrambling identifier.

10. A second terminal in a wireless communication system, wherein the second terminal include: a transceiver configured to communicate with other network entities; as well as A controller, the controller being configured to: receiving a demodulation reference signal DMRS for a physical side link shared channel PSSCH from a first terminal, The sequence of the DMRS for the PSSCH is generated based on a pseudo-random sequence, and Wherein, the pseudo-random sequence is initialized based on a cyclic redundancy check CRC on a physical side link control channel PSCCH, Wherein, the pseudo-random sequence is initialized as follows: in, Generate as follows: and Among them, the n SCID is a fixed value, and the fixed value is 0, in, represents the time slot number in the frame, l represents the OFDM symbol number in the time slot, in, represents the number of symbols per time slot, in, Indicates the decimal value of PSCCH CRC. Among them, p i represents the check digit, and Wherein, L represents the number of check bits.

11. The second terminal according to claim 10, in, The pseudo-random sequence is initialized based on a decimal representation of the CRC on the PSCCH.

12. The second terminal according to claim 10, in, The pseudo-random sequence is initialized based on the scrambling identifier.

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