HK40011157B

HK40011157B - Method for transmitting and receiving synchronization signal block and apparatus therefor

Info

Publication number: HK40011157B
Application number: HK62019000661.4A
Authority: HK
Inventors: Kim Youngsub; Ko Hyunsoo; Kim Kijun; Yoon Sukhyon; Kim Eunsun; Park Haewook
Original assignee: Lg Electronics Inc.
Priority date: 2017-06-15
Filing date: 2018-06-07
Publication date: 2022-09-16

Description

Method for transmitting and receiving sync signal block and apparatus therefor

Technical Field

The present invention relates to a method for transmitting and receiving a synchronization signal block and an apparatus therefor, and more particularly, to a method for transmitting and receiving a synchronization signal block by changing a position at which the synchronization signal block can be transmitted when a parameter set for the synchronization signal block is different from a parameter set of data and an apparatus therefor.

Background

Since more and more communication devices require larger communication services with the current trend, a next generation fifth generation (5G) system is required to provide enhanced wireless broadband communication compared to the conventional LTE system. In such next generation 5G systems, called new RATs, communication scenarios are divided into enhanced mobile broadband (eMBB), ultra-reliable and low latency communication (URLLC), large-scale machine type communication (mtc), etc.

Here, the eMBB is a next generation mobile communication scenario characterized by high spectrum efficiency, high user experience data rate, high peak data rate, etc., the URLLC is a next generation mobile communication scenario characterized by ultra-high reliability, ultra-low latency, and ultra-high availability, etc. (e.g., vehicle-to-all (V2X), emergency services, and remote control), and the mtc is a next generation mobile communication scenario characterized by low cost, low energy, short packets, and large-scale connections (e.g., internet of things (IoT)).

Disclosure of Invention

Technical problem

An object of the present invention is to provide a method for transmitting and receiving a synchronization signal block and an apparatus therefor.

It will be appreciated by those skilled in the art that the objects that can be achieved by the present invention are not limited to what has been particularly described hereinabove and that the above and other objects that can be achieved by the present invention will be clearly understood from the following detailed description.

Technical scheme

A method for receiving a Synchronization Signal Block (SSB) by a terminal in a wireless communication system according to an embodiment of the present invention includes receiving at least one SSB mapped to a plurality of symbols, wherein two regions for candidate SSBs in which the at least one SSB can be received are allocated in a specific time period including the plurality of symbols, wherein a time between the two regions, a time before the two regions, and a time after the two regions are the same in the specific time period.

Here, the candidate SSBs may be arranged in each of the two regions in succession by a first number.

Further, when the subcarrier spacing of the SSB is a first value, 4 symbols may be included in the same time, and when the subcarrier spacing of the SSB is a second value, 8 symbols may be included in the same time.

Further, the regions for the candidate SSBs may be successively arranged by the second number in units of the specific period in a field, and then successively arranged again by the second number after a predetermined time.

Further, when the subcarrier interval of the SSB is a first value, the regions for the candidate SSB may be arranged consecutively by a second number in units of the specific time period, the regions being arranged repeatedly four times at intervals of the predetermined time.

Further, when the subcarrier spacing of the SSB is the first value, the number of slots included in the predetermined time may be 2, and when the subcarrier spacing of the SSB is the second value, the number of slots included in the predetermined time may be 4.

Also, a frequency band in which the terminal operates may be equal to or greater than a certain value.

Further, the same time may be composed of two symbols.

Further, the specific time period in which the two regions are allocated may repeatedly arrange in a localized manner in a field a specific number determined based on the frequency band in which the diagnosis operates.

Further, the specific number may be 2 when the frequency band in which the terminal operates is equal to or less than a specific value, and the specific number may be 4 when the frequency band in which the terminal operates is greater than the specific value.

A terminal for receiving a Synchronization Signal Block (SSB) in a wireless communication system according to the present invention comprises: a transceiver for transmitting/receiving signals to/from a base station; and a processor connected to the transceiver to control the transceiver to receive at least one SSB mapped to a plurality of symbols, wherein two regions for candidate SSBs in which the at least one SSB can be received are allocated in a specific time period including the plurality of symbols, wherein a time between the two regions, a time before the two regions, and a time after the two regions are the same in the specific time period.

A method for transmitting a Synchronization Signal Block (SSB) by a base station in a wireless communication system according to an embodiment of the present invention includes transmitting at least one SSB mapped to a plurality of symbols, wherein two regions for candidate SSBs in which the at least one SSB can be received are allocated within a specific time period including the plurality of symbols, wherein a time between the two regions, a time before the two regions, and a time after the two regions are the same in the specific time period.

A base station for transmitting a Synchronization Signal Block (SSB) in a wireless communication system according to the present invention includes a transceiver for transmitting/receiving a signal to/from a terminal; and a processor connected to the transceiver to control the transceiver to transmit at least one SSB mapped to a plurality of symbols, wherein two regions for candidate SSBs in which the at least one SSB can be received are allocated in a specific time period including the plurality of SSBs, wherein a time between the two regions, a time before the two regions, and a time after the two regions are the same in the specific time period.

Advantageous effects

According to the present invention, even if the parameter set for the synchronization signal block is different from the parameter set for the data, the control information transmission and reception for the data transmission can be efficiently performed.

It will be appreciated by persons skilled in the art that the effects that can be achieved by the present invention are not limited to what has been particularly described hereinabove and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a diagram illustrating a control plane and user plane architecture of a radio interface protocol between a User Equipment (UE) compliant with a third generation partnership project (3GPP) radio access network standard and an evolved UMTS terrestrial radio access network (E-UTRAN).

Fig. 2 is a view for explaining physical channels used in a 3GPP system and a general signal transmission method using the physical channels.

Fig. 3 is an example illustrating a radio frame structure for transmitting a Synchronization Signal (SS) in a Long Term Evolution (LTE) system.

Fig. 4 is a view illustrating an exemplary slot structure available in a new radio access technology (NR).

Fig. 5 is a diagram illustrating an exemplary connection scheme between a transceiver unit (TXRU) and an antenna element.

Fig. 6 is a view abstractly illustrating a hybrid beamforming structure in terms of TXRUs and physical antennas.

Fig. 7 is a view illustrating a beam scanning operation for a synchronization signal and system information during Downlink (DL) transmission.

Fig. 8 is a diagram illustrating an exemplary cell in an NR system.

Fig. 9 to 14 illustrate examples of configuring an SS burst according to a subcarrier spacing of an SSB.

Fig. 15 to 29 show examples of configuring candidate SSBs in an SS burst.

Fig. 30 and 31 show examples of indicating an actually transmitted ATSS among candidate SSBs.

Fig. 32 is a block diagram of a communication device according to an embodiment of the present invention.

Detailed Description

The configuration, operation, and other features of the present invention will be readily understood by the embodiments of the present invention described with reference to the accompanying drawings. The embodiments of the present invention set forth herein are examples in which the technical features of the present invention are applied to a third generation partnership project (3GPP) system.

Although embodiments of the present invention are described in the context of Long Term Evolution (LTE) and LTE-advanced (LTE-a) systems and NR systems, they are purely exemplary. Thus, embodiments of the present invention are applicable to any other communication system as long as the above definition is valid for the communication system.

The term "base station" (BS) may be used to cover the meaning of terms including Remote Radio Heads (RRHs), evolved node BS (enbs or enodebs), Transmission Points (TPs), Reception Points (RPs), relay stations, and the like.

The 3GPP communication standard defines Downlink (DL) physical channels corresponding to Resource Elements (REs) carrying information originating from higher layers and DL physical signals used in the physical layer and corresponding to REs not carrying information originating from higher layers. For example, a Physical Downlink Shared Channel (PDSCH), a Physical Broadcast Channel (PBCH), a Physical Multicast Channel (PMCH), a Physical Control Format Indicator Channel (PCFICH), a Physical Downlink Control Channel (PDCCH), and a physical hybrid ARQ indicator channel (PHICH) are defined as DL physical channels, and a Reference Signal (RS) and a Synchronization Signal (SS) are defined as DL physical signals. The RS, also referred to as a pilot signal, is a signal having a predetermined special waveform known to both the g node b (gnb) and the UE. For example, cell-specific RS, UE-specific RS (UE-RS), positioning RS (prs), and channel state information RS (CSI-RS) are defined as DL RS. The 3GPP LTE/LTE-a standard defines Uplink (UL) physical channels corresponding to REs carrying information originating from higher layers and UL physical signals used in the physical layer and corresponding to REs not carrying information originating from higher layers. For example, a Physical Uplink Shared Channel (PUSCH), a Physical Uplink Control Channel (PUCCH), and a Physical Random Access Channel (PRACH) are defined as UL physical channels, and a demodulation reference signal (DMRS) for UL control/data signals, and a Sounding Reference Signal (SRS) for UL channel measurement are defined as UL physical signals.

In the present invention, PDCCH/PCFICH/PHICH/PDSCH refers to a set of time-frequency resources or a set of REs, which carry Downlink Control Information (DCI)/Control Format Indicator (CFI)/DL acknowledgement/negative acknowledgement (ACK/NACK)/DL data, respectively. In addition, PUCCH/PUSCH/PRACH refers to a set of time-frequency resources or a set of REs that are distributed to carry UL Control Information (UCI)/UL data/random access signals. In the present invention, in particular, the time-frequency resources or REs allocated to or belonging to PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH are referred to as PDCCH RE/PCFICH RE/PHICH RE/PDSCH RE/PUSCH RE/PRACH RE or PDCCH resource/PCFICH resource/PHICH resource/PDSCH resource/PUCCH resource/PUSCH resource/PRACH resource. Hereinafter, if it is said that the UE transmits PUCCH/PUSCH/PRACH, this means that UCI/UL data/random access signals are transmitted on or through the PUCCH/PUSCH/PRACH. Furthermore, if it is said that the gNB transmits PDCCH/PCFICH/PHICH/PDSCH, this means that DL data/control information is transmitted on or through PDCCH/PCFICH/PHICH/PDSCH.

Hereinafter, Orthogonal Frequency Division Multiplexing (OFDM) symbols/subcarriers/REs to which CRS/DMRS/CSI-RS/SRS/UE-RS is allocated or configured are referred to as CRS/DMRS/CSI-RS/SRS/UE-RS symbols/carriers/subcarriers/REs. For example, an OFDM symbol to which a Tracking Rs (TRS) is allocated or configured is referred to as a TRS symbol, a subcarrier to which a TRS is allocated or configured is referred to as a TRS subcarrier, and an RE to which a TRS is allocated or configured is referred to as a TRS RE. Also, a subframe configured to transmit the TRS is referred to as a TRS subframe. Also, a subframe in which a broadcast signal is transmitted is referred to as a broadcast subframe or a PBCH subframe, and a subframe in which a Synchronization Signal (SS), e.g., a Primary Synchronization Signal (PSS) and/or a Secondary Synchronization Signal (SSs), is transmitted is referred to as an SS subframe or a PSS/SSs subframe. The OFDM symbols/subcarriers/REs to which the PSS/SSS is allocated or configured is referred to as PSS/SSS symbols/subcarriers/REs.

In the present invention, a CRS port, a UE-RS port, a CSI-RS port, and a TRS port refer to an antenna port configured to transmit CRS, an antenna port configured to transmit UE-RS, and an antenna port configured to transmit CSI-RS, respectively; and an antenna port configured to transmit the TRS. Antenna ports configured to transmit the CRS may be distinguished from each other according to positions of REs occupied by the CRS ports by the CRS, antenna ports configured to transmit the UE-RS may be distinguished from each other according to positions of REs occupied by the UE-RS ports by the UE-RS, and antenna ports configured to transmit the CSI-RS may be distinguished from each other according to positions of REs occupied by the CSI-RS ports by the CSI-RS. Thus, the term CRS/UE-RS/CSI-RS/TRS port is also used to refer to the pattern of REs occupied by CRS/UE-RS/CSI-RS/TRS in a predetermined resource region.

Fig. 1 illustrates control plane and user plane structures in a radio interface protocol compliant with a 3GPP radio access network standard between a User Equipment (UE) and an evolved UMTS terrestrial radio access network (E-UTRAN). The control plane is a path in which the UE and the network transmit control messages to manage a call, and the user plane is a path in which data (e.g., voice data or internet packet data) generated from an application layer is transmitted.

The physical layer, which is the layer 1, provides an information transfer service to its higher layers using a physical channel. The physical layer is connected to a Medium Access Control (MAC) layer of a higher layer via a transport channel. Data is transferred between the MAC layer and the physical layer through the transport channel. Data is transmitted on a physical channel between physical layers of a transmitting side and a receiving side. The physical channel uses time and frequency as radio resources. Specifically, the physical channel is modulated with Orthogonal Frequency Division Multiple Access (OFDMA) for the Downlink (DL) and single carrier frequency division multiple access (SC-FDMA) for the Uplink (UL).

The MAC layer of layer 2 provides services to its higher layer (radio link control (RLC) layer) via a logical channel. The RLC layer of layer 2 supports reliable data transmission. RLC layer functions may be implemented in functional blocks within the MAC. A Packet Data Convergence Protocol (PDCP) layer of the layer 2 performs a header compression function to reduce an unnecessary amount of control information, and thus, efficiently transmits Internet Protocol (IP) packets, such as IP version 4(IPv4) or IP version 6(IPv6), via a radio interface having a narrow bandwidth.

A Radio Resource Control (RRC) layer at the lowest portion of the layer 3 is defined only on the control plane. The RRC layer controls logical channels, transport channels, and physical channels with respect to configuration, reconfiguration, and release of Radio Bearers (RBs). The radio bearer refers to a service provided at layer 2 for data transmission between the UE and the network. For this purpose, the RRC layers of the UE and the network exchange RRC messages with each other. If an RRC connection has been established between the UE and the network, the UE is in an RRC connected mode, and otherwise, the UE is in an RRC idle mode. A non-access stratum (NAS) layer above the RRC layer performs functions including session management and mobility management, etc.

Downlink transport channels for transferring data from the network to the UE include a Broadcast Channel (BCH) transmitting system information, a Paging Channel (PCH) transmitting a paging message, and a downlink Shared Channel (SCH) transmitting user traffic or control messages, etc. Downlink multicast traffic or control messages or downlink broadcast service traffic or control messages may be transmitted on the downlink SCH or a separately defined downlink Multicast Channel (MCH). Uplink transport channels for communicating data from the UE to the network include a Random Access Channel (RACH) for transmitting an initial control message and an uplink SCH for transmitting user traffic or control messages. Logical channels defined on top of the transport channels and mapped to the transport channels include a Broadcast Control Channel (BCCH), a Paging Control Channel (PCCH), a Common Control Channel (CCCH), a Multicast Control Channel (MCCH), a Multicast Traffic Channel (MTCH), and the like.

Fig. 2 is a view for explaining a physical channel used in a 3GPP system and a general method of transmitting a signal using the physical channel.

Referring to fig. 2, when a UE is powered on or enters a new cell, the UE performs an initial cell search operation (S201). Initial cell search involves acquiring synchronization to a base station, etc. Specifically, the UE synchronizes its timing to the base station and acquires a cell Identifier (ID) and other information by receiving a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from the base station. The UE may then acquire the information broadcast in the cell by receiving a Physical Broadcast Channel (PBCH) from the base station. During initial cell search, the UE may monitor a downlink reference signal (DL RS) channel state by receiving a DL RS.

After the initial cell search, the UE may receive a Physical Downlink Shared Channel (PDSCH) based on a Physical Downlink Control Channel (PDCCH) and information included in the PDCCH to acquire detailed system information (S202).

If the UE initially accesses the base station or does not have radio resources for signal transmission to the base station, the UE may perform a random access procedure with the base station (S203 to S206). In the random access procedure, the UE may transmit a predetermined sequence as a preamble on a Physical Random Access Channel (PRACH) (S203 and S205), and may receive a response message to the preamble on the PDCCH and the PDSCH associated with the PDCCH (S204 and S206). In case of the contention-based RACH, the UE may additionally perform a contention resolution procedure.

After the above procedure, the UE may receive a PDCCH and/or a PDSCH from the eNB (S207) and transmit a Physical Uplink Shared Channel (PUSCH) and/or a Physical Uplink Control Channel (PUCCH) to the eNB (S208), which is a general DL and UL signal transmission procedure. Specifically, the UE receives Downlink Control Information (DCI) on the PDCCH. Here, the DCI includes control information such as resource allocation information for the UE. Different DCI formats are defined according to different usage purposes of DCI.

The control information that the UE transmits to the base station on UL or receives from the base station on DL includes: DL/UL acknowledgement/negative acknowledgement (ACK/NACK) signals, Channel Quality Indicators (CQIs), Precoding Matrix Indices (PMIs), Rank Indicators (RIs), and the like. In the 3GPP LTE system, the UE may transmit control information such as CQI, PMI, RI, and the like on the PUSCH and/or PUCCH.

Fig. 3 is an example illustrating a radio frame structure for transmitting a Synchronization Signal (SS) in an LTE/LTE-a based wireless communication system. In particular, fig. 3 illustrates an example of a radio frame structure for transmitting a synchronization signal and a PBCH in Frequency Division Duplex (FDD). Fig. 3(a) shows the locations where the SS and the PBCH are transmitted in a radio frame configured by a normal Cyclic Prefix (CP) and fig. 3(b) shows the locations where the SS and the PBCH are transmitted in a radio frame configured by an extended CP.

The SS will be described in more detail with reference to fig. 3. SSs are classified into Primary Synchronization Signals (PSS) and Secondary Synchronization Signals (SSs). The PSS is used to acquire time domain synchronization, such as OFDM symbol synchronization, slot synchronization, etc., and/or frequency domain synchronization. Also, the SSS is used to acquire frame synchronization, cell group ID, and/or CP configuration of a cell (i.e., information indicating whether to use normal CP or extension). Referring to fig. 3, the PSS and SSS are transmitted through two OFDM symbols in each radio frame. Specifically, the SS is transmitted in the first slot in each of subframe 0 and subframe 5, taking into account the GSM (global system for mobile communications) frame length of 4.6ms, facilitating inter-radio access technology (inter-RAT) measurements. In particular, the PSS is transmitted in the last OFDM symbol in each of the first slot of subframe 0 and the first slot of subframe 5. And, the SSS is transmitted in a last second OFDM symbol in each of the first slot of the subframe 0 and the first slot of the subframe 5. The boundary of the corresponding radio frame may be detected through the SSS. The PSS is transmitted in the last OFDM symbol of the corresponding slot and the SSS is transmitted in the OFDM symbol immediately preceding the OFDM symbol in which the PSS is transmitted. According to the transmission diversity scheme of the SS, only a single antenna port is used. However, a transmission diversity scheme for the SS standard is not separately defined in the current standard.

By detecting the PSS, the UE can know that the corresponding subframe is one of subframe 0 and subframe 5 because the PSS is transmitted once every 5ms, but the UE cannot know whether the subframe is subframe 0 or subframe 5. Therefore, the UE cannot recognize the boundary of the radio frame from the PSS only. That is, frame synchronization cannot be obtained from the PSS only. The UE detects the boundary of a radio frame in such a way that SSS is transmitted twice in one radio frame with different sequences.

By performing a cell search procedure using the PSS/SSS to already demodulate DL signals and determine time and frequency parameters required to perform UL signal transmission at an accurate time, the UE can communicate with the eNB only after obtaining system information necessary for system configuration of the UE from the eNB.

The system information is configured with a Master Information Block (MIB) and a System Information Block (SIB). Each SIB includes a functionally related set of parameters and is classified into MIB, SIB type 1(SIB1), SIB type 2(SIB2), and SIB3 to SIB17 according to the included parameters.

The MIB includes the most frequently transmitted parameters that are essential for the UE to initially access the network served by the eNB. The UE may receive the MIB through a broadcast channel (e.g., PBCH). The MIB includes a downlink system bandwidth (DL BW), PHICH configuration, and a System Frame Number (SFN). Accordingly, the UE can explicitly know information about DL BW, SFN, and PHICH configuration by receiving PBCH. On the other hand, the UE may implicitly know information about the number of transmission antenna ports of the eNB by receiving the PBCH. Information about the number of transmit antennas of the eNB is implicitly signaled by masking (e.g., XOR operation) a sequence corresponding to the number of transmit antennas to a 16-bit Cyclic Redundancy Check (CRC) for detecting errors of the PBCH.

The SIB1 includes not only information about the time domain scheduling of other SIBs, but also parameters necessary to determine whether a particular cell is suitable for cell selection. The UE receives the SIB1 via broadcast signaling or dedicated signaling.

The DL carrier frequency and corresponding system bandwidth can be obtained through MIB carried by PBCH. The UL carrier frequency and the corresponding system bandwidth can be obtained through system information corresponding to the DL signal. After receiving the MIB, if there is no valid system information stored in the corresponding cell, the UE applies the value of DL BW included in the MIB to UL bandwidth until system information block type 2(SystemInformationBlockType2, SIB2) is received. For example, if the UE obtains the SIB2, the UE can identify the entire UL system bandwidth that can be used for UL transmission through UL carrier frequency and UL bandwidth information included in the SIB 2.

In the frequency domain, the PSS/SSS and PBCH are transmitted regardless of the actual system bandwidth of a total of 6 RBs (i.e., 3 RBs on the left and 3 RBs on the right with respect to the DC subcarrier within the corresponding OFDM symbol). In other words, the PSS/SSS and PBCH are transmitted in only 72 subcarriers. Thus, the UE is configured to detect or decode SS and PBCH regardless of the downlink transmission bandwidth configured for the UE.

After the initial cell search has been completed, the UE can perform a random access procedure to complete access to the eNB. To this end, the UE transmits a preamble via a PRACH (physical random access channel), and is able to receive a response message via the PDCCH and the PDSCH in response to the preamble. In case of contention-based random access, it may transmit an additional PRACH and perform a contention resolution procedure, such as a PDCCH and a PDSCH corresponding to the PDCCH.

After performing the above-described procedure, the UE can perform PDCCH/PDSCH reception and PUSCH/PUCCH transmission as a general UL/DL signal transmission procedure.

The random access procedure is also referred to as a Random Access Channel (RACH) procedure. The random access procedure is used for various purposes including initial access, UL synchronization adjustment, resource allocation, handover, and the like. The random access procedure is classified into a contention-based procedure and a dedicated (i.e., non-contention-based) procedure. Generally, a contention-based random access procedure is generally used to perform initial access. On the other hand, the dedicated random access procedure is restrictively used to perform handover or the like. When performing a contention-based random access procedure, the UE randomly selects a RACH preamble sequence. Therefore, multiple UEs can simultaneously transmit the same RACH preamble sequence. As a result, a contention resolution process is required thereafter. In contrast, when performing the dedicated random access procedure, the UE uses a RACH preamble sequence exclusively allocated to the UE by the eNB. Accordingly, the UE can perform the random access procedure without colliding with a different UE.

The contention-based random access procedure includes 4 steps described below. The messages sent via the 4 steps 1-4 can be referred to in the present invention as messages (Msg) 1-4, respectively.

-step 1: RACH preamble (via PRACH) (UE to eNB)

-step 2: random Access Response (RAR) (via PDCCH and PDSCH) (eNB to UE)

-step 3: layer 2/layer 3 messages (via PUSCH) (UE to eNB)

-step 4: contention resolution message (eNB to UE)

On the other hand, the dedicated random access procedure includes 3 steps described below. The messages sent via the 3 steps 0-2 can be referred to in the present invention as messages (Msg) 0-2, respectively. It may also perform uplink transmission corresponding to PAR (i.e., step 3) as part of the random access procedure. The PDCCH (hereinafter, PDCCH order) can be used to trigger a dedicated random access procedure, which is used for the base station to instruct transmission of the RACH preamble.

-step 0: RACH preamble allocation via dedicated signaling (eNB to UE)

-step 1: RACH preamble (via PRACH) (UE to eNB)

-step 2: random Access Response (RAR) (via PDCCH and PDSCH) (eNB to UE)

After transmitting the RACH preamble, the UE attempts to receive a Random Access Response (RAR) in a pre-configured time window. Specifically, the UE attempts to detect a PDCCH (hereinafter, RA-RNTI PDCCH) having an RA-RNTI (random Access RNTI) in a time window (e.g., masking a CRC with the RA-RNTI in the PDCCH). If RA-RNTI PDCCH is detected, the UE checks if there is RAR for the UE in the PDSCH corresponding to RA-RNTI PDCCH. The RAR includes Timing Advance (TA) information indicating timing offset information for UL synchronization, UL resource allocation information (UL grant information), a temporary UE identifier (e.g., temporary cell-RNTI, TC-RNTI), and the like. The UE can perform UL transmission (e.g., message 3) according to the TA value and resource allocation information included in the RAR. HARQ is applied to UL transmissions corresponding to RARs. Specifically, the UE can receive reception response information (e.g., PHICH) corresponding to Msg3 after transmitting Msg 3.

The random access preamble (i.e., RACH preamble) is formed of a length T in the physical layer_CPHas a cyclic prefix and a length of T_SEQThe sequence portion of (a). T is_CPT of_SEQDepending on the frame structure and the random access configuration. Preamble format is composed ofAnd (4) controlling layers. The RACH preamble is transmitted in a UL subframe. The transmission of the random access preamble is limited to a specific time resource and frequency resource. These resources are referred to as PRACH resources. To match the index 0 with lower numbered PRBs and subframes in a radio frame, PRACH resources are numbered in ascending order of PRBs in subframe number and frequency domain within the radio frame. Random access resources are defined according to PRACH configuration indexes (refer to 3GPP TS36.211 standard documents). The PRACH configuration index is provided by higher layer signals (transmitted by the eNB).

In the LTE/LTE-a system, the subcarrier spacing of the random access preamble (i.e., RACH preamble) is specified to be 1.25kHz and 7.5kHz, respectively, for preamble formats 0 to 3 and 4 (refer to 3GPP TS 36.211).

< OFDM parameter set >

The new RAT system employs an OFDM transmission scheme or a transmission scheme similar to the OFDM transmission scheme. The new RAT system may use different OFDM parameters than those of LTE. Alternatively, the new RAT system may follow the set of parameters of legacy LTE/LTE-a, but with a larger system bandwidth (e.g., 100 MHz). Or one cell may support multiple parameter sets. That is, UEs operating with different sets of parameters may coexist within one cell.

In the 3GPP LTE/LTE-A system, the radio frame used is 10ms (307200T)_s) Long, comprising 10 equally sized Subframes (SF). Numbers may be respectively assigned to 10 SFs of one radio frame. Ts represents the sampling time and is denoted as T_s1/(2048 × 15 kHz). Each SF is 1ms in length and includes two slots. The 20 slots of a radio frame may be numbered sequentially from 0 to 19. Each slot is 0.5ms in length. The time taken to transmit one SF is defined as a Transmission Time Interval (TTI). The time resources may be distinguished by radio frame numbers (or radio frame indexes), SF numbers (or SF indexes), slot numbers (or slot indexes), and the like. TTI refers to an interval in which data can be scheduled. For example, in current LTE/LTE-a systems, there is a transmission opportunity for UL grant or DL grant every 1ms, without multiple us for less than 1msAn L/DL grant opportunity. Thus, in a legacy LTE/LTE-A system, the TTI is 1 ms.

Fig. 4 illustrates an exemplary slot structure available in a new radio access technology (NR).

To minimize data transmission delay, a time slot structure is considered in a fifth generation (5G) new RAT, in which control channels and data channels are multiplexed in Time Division Multiplexing (TDM).

In fig. 4, a region marked with diagonal lines indicates a transmission region of a DL control channel (e.g., PDCCH) carrying DCI, and a black portion indicates a transmission region of a UL control channel (e.g., PUCCH) carrying UCI. DCI is control information transmitted by the gNB to the UE and may include information on cell configuration that the UE should know, DL specific information (such as DL scheduling), UL specific information (such as UL grant), and the like. Also, UCI is control information that the UE transmits to the gNB. The UCI may include HARQ ACK/NACK reporting for DL data, CSI reporting for DL channel status, Scheduling Request (SR), etc.

In fig. 4, in the symbol field of symbol index 1 to symbol index 12, the physical channel (e.g., PDSCH) carrying DL data may be transmitted, and the physical channel (e.g., PUSCH) carrying UL data may also be transmitted. According to the slot structure illustrated in fig. 2, when DL transmission and UL transmission occur sequentially in one slot, transmission/reception of DL data and reception/transmission of UL ACK/NACK for the DL data may be performed in one slot. Accordingly, when an error is generated during data transmission, it is possible to reduce the time taken to retransmit data, thereby minimizing the delay of final data transmission.

In this slot structure, a time gap is required to allow the processes of the gNB and the UE switching from the transmission mode to the reception mode or from the reception mode to the transmission mode. For such a switching procedure between the transmission mode and the reception mode, some OFDM symbols corresponding to the DL-to-UL switching time are configured as Guard Periods (GP) in the slot structure.

In a conventional LTE/LTE-a system, DL control channels are multiplexed with data channels in TDM, and control channels PDCCH are transmitted distributed over the entire system band. However, in the new RAT, it is expected that the bandwidth of one system will be at least about 100MHz, which makes it unsuitable to spread the transmission of control channels over the entire frequency band. This may increase battery consumption of the UE and reduce efficiency for data transmission/reception if the UE monitors the total frequency band to receive the DL control channel. Therefore, in the present invention, the DL control channel can be transmitted in a centralized or distributed manner in the system band, i.e., some bands within the channel band.

In the NR system, the basic transmission unit is a slot. The slot duration includes 14 symbols each having a normal Cyclic Prefix (CP), or 12 symbols each having an extended CP. Furthermore, the time slots are scaled in time by a function of the subcarrier spacing used. That is, as the subcarrier spacing increases, the length of the slot decreases. For example, given 14 symbols per slot, if the number of slots in a 10ms frame is 10 for a 15kHz subcarrier spacing, then the number of slots is 20 for a 30kHz subcarrier spacing and 40 for a 60kHz subcarrier spacing. As the subcarrier spacing increases, the length of the OFDM symbol decreases. The number of OFDM symbols per slot is different depending on a normal CP or an extended CP, and does not vary according to a subcarrier spacing. Considering the basic 15-kHz subcarrier spacing and maximum FFT size 2048, the basic time unit for LTE, T_sDefined as 1/(15000 x 2048) seconds. T is_sWhich is also the sampling time of the 15kHz subcarrier spacing. In the NR system, many other subcarrier intervals other than 15kHz are available, and since the subcarrier intervals are inversely proportional to the corresponding time lengths, the actual sampling time T corresponding to the subcarrier intervals greater than 15kHz_sBecomes shorter than 1/(15000 × 2048) seconds. For example, the actual sampling times for subcarrier intervals of 30kHz, 60kHz and 120kHz may be 1/(2 × 15000 × 2048) seconds, 1/(4 × 15000 × 2048) seconds and 1/(8 × 15000 × 2048) seconds, respectively.

< analog beamforming >

For the 5G mobile communication system in question, a technique using an ultra high frequency band, i.e., a millimeter wave band at 6GHz or more, in order to transmit data to a plurality of users at a high transmission rate in a wide frequency band is considered. The 3GPP refers to this technology as NR, and thus the 5G mobile communication system will be referred to as an NR system in the present invention. However, the millimeter wave band has such a frequency characteristic that a signal attenuates too quickly according to distance due to the use of an excessively high frequency band. Therefore, NR systems using frequency bands at or above at least 6GHz employ a narrow beam transmission scheme in which signals are transmitted in a specific direction with concentrated energy, rather than being transmitted omni-directionally, thereby compensating for fast propagation attenuation and thus overcoming the reduction in coverage caused by the fast propagation attenuation. However, if a service is provided only by using one narrow beam, service coverage of one base station becomes narrow, and thus the base station provides a service in a wide band by collecting a plurality of narrow beams.

Since the wavelength becomes short in the millimeter wave band, that is, the millimeter wave (mmW) band, a plurality of antenna elements can be mounted in the same area. For example, in a two-dimensional (2D) array on a 5cm × 5cm board, a total of 100 antenna elements may be mounted at intervals of 0.5 λ (wavelength) in a 30GHz band having a wavelength of about 1 cm. Therefore, it is considered to increase the beam forming gain by using a plurality of antenna elements at mmW, thereby increasing the coverage or throughput.

In order to form a narrow beam in the millimeter-wave band, a beamforming scheme in which a base station or a UE transmits the same signal with an appropriate phase difference through a plurality of antennas, thereby increasing energy only in a specific direction, is mainly considered. Such beamforming schemes include digital beamforming for generating phase differences between digital baseband signals, analog beamforming for generating phase differences between modulated analog signals by using time delays (i.e., cyclic shifts), and hybrid beamforming using both digital and analog beamforming, among others. Independent beamforming per frequency resource is possible if a TXRU is provided for each antenna element to enable control of the transmission power and phase to each antenna. However, it is not efficient to install TXRUs for all of about 100 antenna elements at cost. That is, in order to compensate for fast propagation attenuation in the millimeter-band, a plurality of antennas should be used, and digital beamforming requires as many RF components (e.g., digital-to-analog converters (DACs), mixers, power amplifiers, and linear amplifiers) as the number of antennas. Therefore, implementing digital beamforming in the millimeter-wave band faces a problem of an increase in the price of the communication device. Therefore, in the case where a large number of antennas are required in the millimeter-wave band, analog beamforming or hybrid beamforming is considered. In analog beamforming, multiple antenna elements are mapped to one TXRU, and the direction of the beam is controlled by an analog phase shifter. A disadvantage of this analog beamforming scheme is that frequency selective Beamforming (BF) cannot be provided because only one beam direction can be generated in the entire frequency band. The hybrid BF is between digital BF and analog BF, where fewer than Q TXRUs are used for the antenna elements. In the hybrid BF, although the number of beam directions is different depending on the connections between the B TXRUs and the Q antenna elements, the direction of beams that can be simultaneously transmitted is limited to B or below B.

Fig. 5 is a diagram illustrating an exemplary connection scheme between a TXRU and an antenna element.

Fig. 5(a) illustrates a connection between the TXRU and the sub-array. In this case, the antenna element is connected to only one TXRU. In contrast, (b) of fig. 5 illustrates connections between the TXRU and all antenna elements. In this case, the antenna element is connected to all TXRUs. In fig. 5, W represents a phase vector subjected to multiplication in the analog phase shifter. That is, the direction of analog beamforming is determined by W. Here, the CSI-RS antenna ports may be mapped to the TXRUs in a one-to-one or one-to-many correspondence.

As described previously, since a digital baseband signal to be transmitted or a received digital baseband signal is subjected to signal processing in digital beamforming, signals can be simultaneously transmitted or received in or from a plurality of directions on a plurality of beams. In contrast, in analog beamforming, an analog signal to be transmitted or a received analog signal is beamformed in a modulation state. Therefore, signals cannot be simultaneously transmitted or received in or from multiple directions outside the coverage of one beam. Base stations typically rely on broadband transmission or multi-antenna characteristics to communicate with multiple users simultaneously. If the base station uses analog BF or hybrid BF and forms an analog beam in one beam direction, the base station has no choice but to communicate only with users covered in the same analog beam direction, given the nature of analog BF. By reflecting the drawbacks caused by the nature of analog BF or hybrid BF, the RACH resource allocation and base station resource utilization scheme described later according to the present invention is proposed.

Fig. 6 abstractly illustrates a hybrid beamforming structure in terms of TXRUs and physical antennas.

For the case of using multiple antennas, hybrid BF has emerged where digital BF is combined with analog BF. Analog BF (or RF BF) is an operation of performing precoding (or combining) in an RF unit. Due to the precoding (or combination) in each of the baseband unit and the RF unit, the hybrid BF provides a benefit of performance approaching that of a digital BF, while reducing the number of RF chains and the number of DACs (or analog-to-digital converters (ADCs)). For convenience, the hybrid BF structure may be represented with N TXRUs and M physical antennas. The digital BF of the L data layers to be transmitted by the transmitting end may be represented as an N × L matrix, and then the N converted digital signals are converted into analog signals by the TXRU and applied with the analog BF represented as an M × N matrix. In fig. 6, the number of digital beams is L, and the number of analog beams is N. Further, it is considered in the NR system that a base station is configured to change an analog BF based on a symbol in order to more efficiently support BF for a UE located in a specific region. Further, when N TXRUs and M RF antennas are defined by one antenna panel, the NR system also considers introducing a plurality of antenna panels to which mutually independent hybrid BF is applicable. As such, in the case where the base station uses multiple analog beams, the analog beams at each UE that facilitate signal reception may be different. Therefore, a beam sweeping operation is being considered in which, for at least SS, system information, and paging, etc., the base station changes the applicable multiple analog beams based on the symbol in a specific slot or SF to allow all UEs to have a reception opportunity.

Fig. 7 is a view illustrating a beam scanning operation for SS and system information during DL transmission. In fig. 7, a physical resource or a physical channel broadcasting system information of the new RAT system is referred to as xPBCH. At this time, analog beams from mutually different antenna panels may be simultaneously transmitted in one symbol, and introduction of a Beam Reference Signal (BRS) as a reference signal (BS) transmitted for a single analog beam corresponding to a specific antenna panel is being discussed, as illustrated in fig. 7, in order to measure a channel of each analog beam. The BRS may be defined for a plurality of antenna ports, and each antenna port of the BRS may correspond to a single analog beam. Unlike the BRS, the SS or xPBCH can be transmitted for all analog beams included in the analog beam group so that any UE can successfully receive the SS or xPBCH.

Fig. 8 is a diagram illustrating an exemplary cell in an NR system.

Referring to fig. 8, a scheme of forming one cell by a plurality of TRPs is being discussed in an NR system, compared to a wireless communication system such as conventional LTE in which one base station forms one cell. If a plurality of TRPs form one cell, seamless communication is possible even if the TRP serving the UE is changed, thereby having an advantage of easily managing mobility of the UE.

In contrast to the LTE/LTE-a system that omnidirectionally transmits PSS/SSS, a method for transmitting signals such as PSS/SSS/PBCH by BF performed by sequentially switching beam directions to all directions at a gNB to which millimeter waves are applied is considered. Such signal transmission/reception performed by switching the beam direction is called beam sweeping (beam sweeping) or beam scanning (beam sweeping). In the present invention, "beam sweep" is a behavior of the transmission side, and "beam sweep" is a behavior of the reception side. For example, if up to N beam directions are available for the gNB, the gNB transmits signals such as PSS/SSS/PBCH in the N beam directions, respectively. That is, the gNB transmits SSS such as PSS/SSS/PBCH in each direction by sweeping beams in directions available to or supported by the gNB. Or if the gNB is capable of forming N beams, each of the plurality of beams may be configured into one beam group, and the PSS/SSS/PBCH may be transmitted/received per beam group. At this time, one beam group includes one or more beams. Signals such as PSS/SSS/PBCH transmitted in the same direction may be defined as one SS block (SSB), and there may be a plurality of SSBs in one cell. If there are multiple SSBs, each SSB may be identified using an SSB index. For example, if PSS/SSS/PBCH is transmitted in 10 beam directions in one system, the PSS/SSS/PBCH transmitted in the same direction may form one SSB, and it can be understood that there are 10 SSBs in the system. In the present invention, the beam index may be interpreted as an SSB index.

Before describing the present invention, the location of arranging each SSB described in the present invention means the location of a resource region in which SSBs can be transmitted, and thus may be referred to as a candidate SSB as a resource region in which SSBs can be transmitted.

That is, although the location or resource region of the candidate SSB in which the SSB can be transmitted is defined in the present invention, the SSB is not necessarily transmitted in the defined location of the candidate SSB. In other words, while SSBs can be sent at defined locations of candidate SSBs, there may be candidate SSB locations that do not send SSBs in some cases. Thus, in addition to the definition of candidate SSB locations, the present invention additionally describes a method of indicating information about the actually transmitted synchronization signal blocks (ATSS).

In addition, the SS burst proposed in the present invention is a bundling position of candidate SSBs, and represents a set or arrangement of candidate SSBs in a specific duration or a specific time unit. The SS bursts may have different specific durations or specific time units according to subcarrier intervals. For example, when the number of OFDM symbols included in one symbol is 14, an SS burst having a subcarrier spacing of 15kHz or 30kHz used in a frequency band of 6GHz or less may refer to a set or arrangement of candidate SSBs included in one slot, and an SS burst having a subcarrier spacing of 120kHz or 240kHz used in a frequency band of 6GHz or more may refer to a set or arrangement of candidate SSBs included within 0.25 ms.

Further, the set of SS bursts is a bundle of the above-described SS bursts, and may refer to a set or arrangement of SS bursts in a unit time of 5 ms.

Hereinafter, the present invention describes a method of configuring a set of SS bursts according to a subcarrier spacing (SCS) of a Synchronization Signal Block (SSB) in a system supporting a new rat (nr).

In NR, all SSBs are positioned within a 5ms window regardless of the periodicity of the set of SS bursts. In addition, the number of SSBs that need to be located within 5ms is defined differently depending on the frequency range.

For example, in a frequency band of 3GHz or lower, a maximum of 4 SSBs are arranged within a 5ms window, and in a frequency band of 3GHz to 6GHz, a maximum of 8 SSBs are arranged within a 5ms window. In addition, in a frequency band of 6GHz or higher, a maximum of 64 SSBs may be arranged within a 5ms window. Further, as the subcarrier spacing of the SSB, 15kHz or 30kHz may be used in a band of 6GHz or less, and 120kHz or 240kHz may be used in a band of 6GHz or more. However, it is assumed in the present invention that only a subcarrier spacing of 15kHz is used in a frequency band of 3GHz or lower.

In order to satisfy the above condition, the SS burst set needs to be configured such that a maximum of 4 or 8 SSBs are arranged within 5ms at a subcarrier interval of 15kHz, and the SS burst set needs to be configured such that 8 SSBs are arranged within 5ms at a subcarrier interval of 30 kHz. Further, the SS burst set needs to be configured such that a maximum of 64 SSBs are arranged at subcarrier intervals of 120kHz and 240 kHz.

As shown in table 1, for each subcarrier interval, there are various minimum times required to arrange the maximum number of SSBs from 2ms to 4 ms. Therefore, it is necessary to configure various SS burst sets within a 5ms window.

Thus, the present invention describes how to arrange SSBs within a 5ms window according to subcarrier spacing.

[ Table 1]

1. SS burst set configuration in 3GHz or lower frequency band

It is assumed in the present invention that only the 15kHz subcarrier spacing is used as the subcarrier spacing of the SSB in the 3GHz or lower band. A maximum of 4 SSBs may be included within a 5ms window in a 3GHz or lower frequency band. With a 15kHz subcarrier spacing, a maximum of 2 SSBs can be arranged within 1ms, and thus a minimum of 2ms is required to include a maximum of 4 SSBs. In addition, based on the above description, the SS burst set may be configured in a frequency band of 3GHz or less, as shown in fig. 9.

Examples 1 to 1

As shown in fig. 9(a), an SS burst set configured such that 4 SSBs are arranged within 2ms may be considered. When the set of SS bursts is configured as shown in fig. 9(a), a UE in an idle state can use only 2ms for SSB decoding, and thus is advantageous from the viewpoint of power consumption. If 4 or fewer SSBs are used within the 5ms window, the UE may be notified of the actually transmitted SSB using the bitmap. However, if no bitmap information exists, the UE may assume that the SSB is sent from the front arrangement of candidate SSB transmission positions for SSB transmission.

Examples 1 to 2

In embodiment 1-2, 2 SSBs are defined as a single SS burst unit, and the SS burst units are arranged at predetermined intervals of 1ms or more, as shown in fig. 9 (b). That is, since 2 SSBs constitute a single SS burst, the single SS burst becomes a single SS burst unit in embodiment 1-2. When the set of SS bursts is configured in this manner, the duration in which the SSB is not arranged can be used for uplink transmission, and thus low-delay communication using the same can be performed. If 4 or fewer SSBs are used within the 5ms window, the UE may be notified of the actually transmitted SSB using the bitmap. However, if there is no bitmap information, the UE may assume that the SSB is transmitted from the front arrangement of candidate SSB transmission positions for SSB transmission, or that the SS burst units are alternately arranged. For example, when 2 SSBs are arranged, one SSB may be arranged in a first SS burst unit and the remaining one SSB may be arranged in a second SS burst unit.

2. SS burst aggregation configuration in 3GHz to 6GHz bands

15kHz and 30kHz are used as the subcarrier spacing for SSB in the 3GHz to 6GHz band. Up to 8 SSBs may be arranged within a 5ms window in the respective frequency band. Specifically, up to 2 SSBs may be arranged within 1ms at a subcarrier interval of 15kHz, and up to 2 SSBs may be arranged within 0.5ms at a subcarrier interval of 30 kHz. Therefore, arranging 8 SSBs at 15kHz subcarrier spacing requires at least 4ms, and arranging 8 SSBs at 30kHz subcarrier spacing requires a minimum of 2 ms. Based on this, an embodiment for SS burst set configuration in the 3GHz to 6GHz band is described with reference to fig. 10 and 11.

(1) When the subcarrier spacing of the SSB is 15kHz

Example 2-1

As shown in fig. 10(a), the set of SS bursts may be configured such that all 4 SSBs are arranged within 4 ms. When the set of SS bursts is configured as shown in fig. 10(a), a UE in an idle state can use only 4ms for SSB decoding, and thus is advantageous from the viewpoint of power consumption. If 8 or fewer SSBs are used in the 5ms window, the UE may be notified of the actually transmitted SSBs using the bitmap. However, if no bitmap information exists, the UE may assume that the SSB is sent from the front arrangement of candidate SSB transmission positions for SSB transmission.

Examples 2 to 2

In embodiment 2-2, 4 SSBs are defined as a single SS burst unit, and the SS burst units are arranged at predetermined intervals of 1ms or more, as shown in fig. 10 (b). That is, since 2 SSBs constitute a single SS burst, 2 SS bursts are defined as a single SS burst unit in embodiment 2-2. When the set of SS bursts is configured in this manner, a duration in which the SSB is not configured can be used for uplink transmission, and thus low-delay communication using the same can be performed.

If 8 or fewer SSBs are used within the 5ms window, the UE may be notified of the actually transmitted SSB using the bitmap. However, if there is no bitmap information, the UE may assume that the SSB is transmitted from the front arrangement of candidate SSB transmission positions for SSB transmission, or that the SS burst units are alternately arranged. For example, when 3 SSBs are arranged, one SSB may be arranged in a first SS burst unit, and another SSB may be arranged in a second SS burst unit, and the remaining one SSB may be arranged in the first SS burst unit again.

(2) When the sub-carrier spacing of the SSB is 30kHz

Examples 2 to 3

As shown in fig. 11(a), the SS burst set may be configured such that all 8 SSBs are arranged in 2 ms. When the set of SS bursts is configured as shown in fig. 11(a), a UE in an idle state can use only 2ms for SSB decoding, and thus is advantageous from the viewpoint of power consumption. If 8 or fewer SSBs are used in the 5ms window, the UE may be notified of the actually transmitted SSBs using the bitmap. However, if no bitmap information exists, the UE may assume that the SSB is sent from the front arrangement of candidate SSB transmission positions for SSB transmission.

Examples 2 to 4

In embodiments 2 to 4, N SSBs are defined as a single SS burst unit, and the SS burst units are arranged at predetermined intervals of 0.5ms or more, as shown in fig. 11 (b). When the set of SS bursts is configured in this manner, a duration in which SSBs are not arranged can be used for uplink transmission, and thus low-delay communication using the same can be performed.

If 8 or fewer SSBs are used within the 5ms window, the UE may be notified of the actually transmitted SSB using the bitmap. However, if there is no bitmap information, the UE may assume that the SSB is transmitted from the front arrangement of candidate SSB transmission positions for SSB transmission, or that the SS burst units are alternately arranged. For example, when 3 SSBs are arranged, one SSB may be arranged in a first SS burst unit, and another SSB may be arranged in a second SS burst unit, and the remaining one SSB may be arranged in a third SS burst unit.

3. SS burst set configuration in 6GHz or higher frequency band

120kHz and 240kHz are used as subcarrier spacing for SSB in the 6GHz or higher frequency band. Up to 64 SSBs may be arranged within a 5ms window in the respective frequency band. Up to 2 SSBs may be arranged within 0.125ms at 120kHz subcarrier spacing, and up to 4 SSBs may be arranged within 0.125ms at 240kHz subcarrier spacing. Thus, a minimum of 4ms is required to arrange 64 SSBs at 120kHz subcarrier spacing, and a minimum of 2ms is required to arrange 64 SSBs at 240kHz subcarrier spacing. Based on this, an embodiment for SS burst set configuration in a 6GHz or higher frequency band is described with reference to fig. 12 to 15. In addition, in embodiments 3-1 to 3-3, it is assumed that a single SSB burst unit is configured in units of 8 SSBs in consideration of the smoothing operation of URLLC (ultra-reliable low-delay communication) and the bitmap overhead of indicating information on ATSS to the UE.

Example 3-1

As shown in fig. 12, the set of SS bursts may be configured such that all 64 SSBs are contiguous. Here, fig. 12(a) shows the SS burst set configuration in the case where the subcarrier spacing is 120kHz and fig. 12(b) shows the SS burst set configuration in the case where the subcarrier spacing is 240 kHz.

When the SS burst set is configured as shown in fig. 12, the UE in the idle state can use only 4ms for SSB decoding in the case of 120kHz and only 2ms for SSB decoding in the case of 240kHz, and thus is advantageous from the viewpoint of power consumption. If 64 or fewer SSBs are used in the 5ms window, the UE may be notified of the actual transmitted SS burst using a bitmap. In addition, the UE may know information about the number of SSBs used per SS burst by performing blind detection or using other methods. However, if no bitmap information exists, the UE may assume that the SSB is sent from the front arrangement of candidate SSB transmission positions for SSB transmission.

Examples 3 to 2

In embodiment 3-2, N SSBs are defined as a single SS burst unit, and the SS burst units are arranged at predetermined intervals of 0.125ms or more, as shown in fig. 13. Fig. 13(a) shows the SS burst set configuration in the case where the subcarrier spacing is 120kHz and fig. 13(b) shows the SS burst set configuration in the case where the subcarrier spacing is 240 kHz.

When the set of SS bursts is configured in this manner, the duration in which the SSB is not arranged can be used for uplink transmission, and thus low-delay communication using the same can be performed.

If 64 or fewer SSBs are used within the 5ms window, the UE may be notified of the actual transmitted SS burst using a bitmap. In addition, the UE may know information about the number of SSBs used per SS burst by performing blind detection or using other methods.

However, if there is no bitmap information, the UE may assume that the SSB is transmitted from the front arrangement of candidate SSB transmission positions for SSB transmission, or that the SS burst units are alternately arranged. For example, when 3 SSBs are arranged, one SSB may be arranged in a first SS burst unit, another SSB may be arranged in a second SS burst unit, and the remaining one SSB may be arranged in a third SS burst unit.

Examples 3 to 3

In NR, SSB and data can be multiplexed and transmitted even when the subcarrier spacing of SSB is different from that of data. That is, one of 60kHz and 120kHz may be selected as the subcarrier spacing of data, one of 120kHz and 240kHz may be selected as the subcarrier spacing of SSB, and data and SSB may be multiplexed.

If the subcarrier spacing of data is 60kHz and the subcarrier spacing of SSB is 120kHz, when the SS burst set is configured as in embodiment 3-2, SSB is arranged from the middle of a slot having a subcarrier spacing of 60kHz, as shown in fig. 14 (a).

However, when the SS burst set is configured as shown in fig. 14(a), since symbols for downlink control and symbols for uplink control need to be allocated to the front and rear of the slot in the NR, the control region of the front and rear of the slot with the 60kHz subcarrier spacing may not be guaranteed. Therefore, the SS burst can be reconfigured only in the case where the SS burst is configured such that the control region of the data cannot be guaranteed, as shown in fig. 14 (b).

Alternatively, the SS burst set configuration may be designed according to a 60kHz slot duration. As shown in fig. 15, it is possible to design the SS burst set configuration such that SSBs are arranged from the front of a time slot having a subcarrier spacing of 60kHz while allocating a predetermined duration in which no SSB is arranged for uplink communication, similarly to embodiment 3-2. Here, fig. 15(a) shows an embodiment in which the SSB subcarrier spacing is 120kHz and the data subcarrier spacing is 60kHz, and fig. 15(b) shows an embodiment in which the SSB subcarrier spacing is 240kHz and the data subcarrier spacing is 60 kHz.

Further, it may be considered to add an offset of each cell ID to the SS burst set configuration proposed in embodiments 1-1 to 3-3. When the offset is added, interference from the SSBs of the neighboring cells can be reduced.

< configuration of SS burst >

Now, a method of configuring an SS burst when an SSB subcarrier spacing is different from a data subcarrier spacing in a system supporting NR (new RAT) is described. In NR, a time/frequency resource grid is configured using a data parameter set as a reference parameter set. The SSB may be the same as or different from the reference parameter set and may multiplex a resource grid configured based on the data parameter set.

In addition, in a system supporting NR, each slot may include a symbol for downlink control, a guard period for downlink/uplink switching, and a symbol for uplink control. Here, if a case where SSBs having different subcarrier intervals and data are multiplexed occurs, the SSBs may be mapped overlapping with symbols for downlink control or the like due to a symbol duration difference. In this case, collision between the SSB and the symbol for data control can be avoided according to the configuration of the SS burst, which is a bundling unit of the SSB.

Meanwhile, in the current NR, a slot may consist of 14 OFDM symbols or 7 OFDM symbols. As shown in fig. 16(a) and (b), the SS burst configuration may vary according to the number of symbols of the slot. Therefore, the base station needs to allocate 1 bit to the PBCH content to transmit information indicating that the number of symbols of the current slot is 7 or 14 to the UE, and inform the UE of information on the number of symbols per slot of the neighboring cell through the PBCH content.

Further, the SSB discussed in NR consists of a total of 4 symbols including PSS, SSS, and PBCH, and 2 SSBs may be included in a slot consisting of 14 OFDM symbols, and 1 SSB may be included in a slot consisting of 7 OFDM symbols.

In addition, the SSB may have a subcarrier spacing of 15kHz or 30kHz in a frequency band of 6GHz or lower and a subcarrier spacing of 120kHz or 240kHz in a frequency band of 6GHz or higher. In contrast, the subcarrier spacing for data may be any one of 15kHz, 30kHz, 60kHz, and 120 kHz. Further, referring to the NR slot structure currently discussed, when one slot is composed of 14 OFDM symbols, one slot includes 1 or 2 symbols for downlink control, a guard period, and 2 symbols for uplink control. If one slot is composed of 7 OFDM symbols, the slot includes one symbol for downlink control, a guard period, and 2 symbols for uplink control.

Based on the above description, the present invention describes a method of arranging SSBs in slots when SSBs having different subcarrier spacings and data are multiplexed.

4. SS burst configuration in 6GHz or lower frequency band

Hereinafter, a method of arranging the SSBs when multiplexing the SSBs and data is described. In the frequency band of 6GHz or less, the data subcarrier spacing may be 15kHz, 30kHz, or 60kHz, and the SSB subcarrier spacing may be 15kHz or 30 kHz. In addition, one guard period for downlink/uplink switching and one or two symbols for uplink control are required in a slot, respectively. A method of arranging SSBs in an SS burst based on the above description will be described in embodiments 4-1 to 4-4. It is assumed that the set of SS bursts including the SS bursts described in embodiments 4-1 to 4-4 is configured as shown in fig. 17.

Example 4-1

When SSB having a subcarrier spacing of 15kHz and data having a subcarrier spacing of 30kHz are multiplexed in a slot composed of 14 OFDM symbols, SSB may be arranged as shown in fig. 18. In this case, even when the data subcarrier spacing is 15kHz or 30kHz, the SSB having the subcarrier spacing of 15kHz is arranged not to intrude into the control region. Here, considering the SS burst configuration and the SS burst set configuration shown in fig. 17 and 18, the method of arranging the SSBs within the 5ms window may be arranged as follows.

-15kHz subcarrier spacing

The first OFDM symbol of the candidate SSB has an index of 2,8 +14 x n. Here, n is 0,1 for carrier frequencies lower than or equal to 3GHz, and n is 0,1,2,3 for carrier frequencies higher than 3GHz and lower than or equal to 6 GH.

Example 4 to 2

When SSB having a subcarrier spacing of 30kHz and data having a subcarrier spacing of 60kHz are multiplexed in a slot composed of 14 OFDM symbols, SSB may be arranged as shown in fig. 19. In this case, even when the data subcarrier spacing is 30kHz or 60kHz, the SSB having the subcarrier spacing of 30kHz is arranged not to intrude into the control region. Here, considering the SS burst configuration and the SS burst set configuration shown in fig. 17 and fig. 19, the method of arranging the SSBs within the 5ms window may be arranged as follows.

Sub-carrier spacing of-30 kHz

Examples 4 to 3

When SSB having a subcarrier spacing of 15kHz and data having a subcarrier spacing of 60kHz are multiplexed in a slot composed of 14 OFDM symbols, SSB may be arranged as shown in fig. 20. In this case, the SSB having the 15kHz subcarrier spacing overlaps with the guard period and the uplink control symbol included in the first and third slots of the data having the 60kHz subcarrier spacing and the downlink control symbol included in the second and fourth slots of the data. Accordingly, the first and third slots may be configured as downlink-only slots having no uplink control symbols.

Examples 4 to 4

When SSB having a subcarrier spacing of 15kHz and data having a subcarrier spacing of 30kHz are multiplexed in a slot composed of 7 OFDM symbols, SSB may be arranged as shown in fig. 21. In this case, the SSB having the 15kHz subcarrier spacing overlaps with the guard period and the uplink control symbol included in the first slot of the data having the 30kHz subcarrier spacing and the downlink control symbol included in the second slot of the data. Thus, the first time slot may be configured as a downlink-only time slot without uplink control symbols.

5. SS burst configuration in 6GHz or higher frequency band

Now, the SSB arrangement when SSB and data are multiplexed in a frequency band of 6GHz or higher is described based on embodiments 5-1 to 5-3. In the frequency band of 6GHz or higher, the data subcarrier spacing may be 60kHz or 120kHz, and the SSB subcarrier spacing may be 120kHz or 240 kHz. In addition, one guard period for downlink/uplink switching and one or two symbols for uplink control are required in a slot, respectively. A method of arranging SSBs in an SS burst based on the above description will be described in examples 5-1 to 5-3. Assume that an SS burst set including SS bursts described in embodiments 5-1 to 5-3 is configured as shown in fig. 22.

Example 5-1

When SSB having a subcarrier spacing of 120kHz and data having a subcarrier spacing of 60kHz are multiplexed in a slot composed of 14 OFDM symbols, SSB may be arranged as shown in fig. 23. In this case, the SSB having the subcarrier spacing of 120kHz is arranged not to intrude into the control region even when the data subcarrier spacing is 60kHz or 120 kHz. Here, considering the SS burst configuration and the SS burst set configuration shown in fig. 22 and 23, the method of arranging the SSBs within the 5ms window may be arranged as follows.

120kHz subcarrier spacing

The first OFDM symbol of the candidate SSB has an index of 4,8,16,20 +28 x n. Here, for carrier frequencies above 6GHz, n is 0,1,2,3,5,6,7,8,10,11,12,13,15,16,17, 18.

Examples 5 and 2

When SSB having a subcarrier spacing of 240kHz and data having a subcarrier spacing of 60kHz or 120kHz are multiplexed in a slot composed of 14 OFDM symbols, SSB may be arranged as shown in fig. 24. In this case, SSB having a subcarrier spacing of 240kHz is arranged not to intrude into the control region of data.

Here, considering the SS burst configuration and the SS burst set configuration shown in fig. 22 and 24, the method of arranging the SSBs within the 5ms window may be arranged as follows.

Sub-carrier spacing of 240kHz

The first OFDM symbol of the candidate SSB has an index {8,12,16,20,32,36,40,44} +56 x n. Here, for carrier frequencies above 6GHz, n is 0,1,2,3,5,6,7, 8.

Examples 5 to 3

The SSB arrangement when the SSB having the subcarrier spacing of 120kHz or 240kHz and the data having the subcarrier spacing of 60kHz are multiplexed in the slot composed of 14 OFDM symbols has been described in embodiments 5-1 and 5-2. Further, when all SS burst configurations and SS burst set configurations are considered, a control region of data having a subcarrier spacing of 60kHz may not be guaranteed in the case of a specific SS burst set configuration as shown in fig. 25, as shown in fig. 26.

In other words, if the set of SS bursts is configured as shown in fig. 25 and the SS bursts are configured as in embodiment 5-1, the gap period or downlink control symbol for uplink control transmission may overlap with the SSB as shown in fig. 26.

Therefore, in order to guarantee a specific SS burst set configuration and a guard period for uplink control and 2 downlink control symbols in the SS burst configuration, the SS burst set configuration shown in fig. 26 may be reconfigured as shown in fig. 27. In addition, when the SSB subcarrier spacing is 240kHz, SSBs may be arranged corresponding to the positions of SSBs having a subcarrier spacing of 120kHz of fig. 27. For example, 2 SSBs with a subcarrier spacing of 240kHz may be arranged within a duration corresponding to one SSB with a subcarrier spacing of 120 kHz.

That is, when SSBs are arranged from the middle portion of a slot having a subcarrier spacing of 60kHz, an SS burst set configuration can be represented as shown in fig. 28 and 29. Here, fig. 28 shows a case where the SSB subcarrier spacing is 120kHz and fig. 29 shows a case where the SSB subcarrier spacing is 240 kHz.

Here, considering the SS burst configuration and the SS burst set configuration shown in fig. 25 and fig. 27 to 29, the method of arranging the SSBs within the 5ms window may be arranged as follows.

120kHz subcarrier spacing

The first OFDM symbol of the candidate SSB has an index 4,8,16,20,32,36,44,48, +70 x n. Here, for carrier frequencies above 6GHz, n is 0,2,4, 6.

The first OFDM symbol of the candidate SSB has an index 2,6,18,22,30,34,46,50, +70 x n. Here, for carrier frequencies above 6GHz, n is 1,3,5, 7.

Sub-carrier spacing of 240kHz

The first OFDM symbol of the candidate SSB has an index {8,12,16,20,32,36,40,44,64,68,72,76,88,92,96,100} +140 x n. Here, for carrier frequencies above 6GHz, n is 0, 2.

The first OFDM symbol of the candidate SSB has an index 4,8,12,16,36,40,44,48,60,64,68,72,92,96,100,104, +140 xn. Here, for carrier frequencies above 6GHz, n is 1, 3.

When the SS burst is configured as described above, the symbol in which the SSB is transmitted is fixed regardless of the subcarrier spacing in the 6GHz or higher frequency band. That is, when the slot subcarrier spacing is 60kHz, the SSB may be transmitted in the third to sixth symbols and the ninth to twelfth symbols, and when the SSB has subcarrier spacings of 120kHz and 240kHz from the viewpoint of the SSB, the SSB may be transmitted in symbols that are temporally aligned with symbol positions at which the SSB is transmitted in a slot having a 60kHz subcarrier spacing.

Accordingly, when the UE detects one SSB based on the above description, the UE may estimate the positions of the remaining SSBs. Furthermore, SSBs can be used to make measurements using this information. Additional combining gain can be obtained if SSB combining is allowed in the SS burst.

< method of indicating actually transmitted synchronization Signal Block (ATSS) >

6. Method for indicating ATSS generally

Hereinafter, a method of indicating ATSS to a UE in a system supporting NR (new RAT) will be described. In the current NR, all SSBs are positioned within a 5ms window, regardless of the periodicity of the set of SS bursts. The number of SSBs that need to be located within 5ms is defined in terms of frequency range.

That is, a maximum of 4 SSBs are arranged within 5ms in the frequency band of 3GHz or less, and a maximum of 8 SSBs are arranged within 5ms in the frequency band of 3GHz to 6 GHz. In the frequency band of 6GHz or higher, a maximum of 64 SSBs can be arranged within a 5ms window.

In addition, the SSB may have a subcarrier spacing of 15kHz or 30kHz in a frequency band of 6GHz or less, and may have a subcarrier spacing of 120kHz or 240kHz in a frequency band of 6GHz or more. Meanwhile, each subcarrier spacing defines in the standard document where an SSB can transmit in a set of SS bursts.

It is assumed that ATSS is indicated by Remaining Minimum System Information (RMSI) or Other System Information (OSI) in the present embodiment.

In order to notify ATSS information on a maximum of 64 SSBs, there are a method of notifying only the number of transmitted SSBs and a method of notifying information on all locations using a bitmap. According to the method of informing only the number of ATSSs, the ATSS can be indicated using only up to 6 bits, but flexibility with respect to SSB transmission of the base station is reduced. In contrast, the method using the bitmap provides sufficient flexibility for the base station, but requires 64 bits at most.

However, allocating 64-bit resources to all neighboring cells separately may result in considerable overhead. Therefore, various ATSS indication methods for effectively indicating ATSS need to be considered. Therefore, a method of indicating ATSS in a system supporting NR is described in the present embodiment.

The maximum number of SSBs that can be transmitted in a frequency band of 3GHz or less is 4, and the maximum number of SSBs that can be transmitted in a frequency band of 3GHz to 6GHz is 8. A position where each band can transmit the SSB may be defined as shown in fig. 30 (a). Now, a specific method for indicating ATSS will be described.

Example 6-1

This is a method of indicating only the total number of SSBs sent. That is, a maximum of 4 SSBs are transmitted in a frequency band of 3GHz or less and thus 2 bits are required, and a maximum of 8 SSBs are transmitted in a frequency band of 3GHz to 6GHz and thus 3 bits are required. In this case, although a small number of bits are used, the flexibility of SSB transmission is reduced. That is, the base station needs to sequentially transmit the total number of SSBs from SSB #0 because the base station only knows the total number of SSBs. For example, if the number of transmitted SSBs is 3, SSB #0, SSB #1, and SSB #2 are transmitted in fig. 30 (a).

Example 6 to 2

This is a method of indicating information on the transmitted SSB using a bitmap. That is, a maximum of 4 SSBs are transmitted in a frequency band of 3GHz or lower and thus 4 bits are used, and a maximum of 8 SSBs are transmitted in a frequency band of 3GHz to 6GHz and thus 8 bits are used. In this case, although the number of bits used is increased compared to embodiment 6-1, sufficient flexibility of SSB transmission can be provided. That is, the base station can select a desired SSB from SSBs #0 to #7 and transmit the selected SSB because each SSB index allocates 1 bit.

However, the maximum number of SSBs in the band of 6GHz or more is 64, and a position where an SSB can be transmitted in the band of 6GHz or more is defined as type 1 or type2 of fig. 30 (b). In order to perform sufficiently flexible transmission by a bitmap as in a band of 6GHz or less, 64 bits are required. Even if ATSS indication is performed using RMSI/OSI, the number of bits of 64 bits may play a considerable overhead. Therefore, ATSS can be indicated by the methods of embodiments 6-3 to 6-7 to provide maximum flexibility with a smaller number of bits, but sufficient flexibility cannot be supported.

Examples 6 to 3

This is a method of indicating only the total number of SSBs sent. That is, a maximum of 64 SSBs are transmitted in a frequency band of 6GHz or higher, and thus 6 bits are used. In this case, although a small number of bits are used, the flexibility of SSB transmission is reduced. That is, the base station needs to transmit the total number of SSBs from SSB #0 because the base station only knows the total number of SSBs. For example, referring to type 1 of fig. 30(b), if the number of transmitted SSBs is 16, 16 SSBs of SSB #0 to SSB #15 are transmitted.

Examples 6 to 4

Only the total number of transmitted SSBs is indicated, and the SSBs to be transmitted may be divided into SSB groups and transmitted. In the present embodiment, it is assumed that a single SSB group includes 8 SSBs as in type2 of fig. 30 (b). The base station needs 6 bits to inform the UE of information about the number of ATSSs in the 64 SSBs, and can use the information to identify the number of actually transmitted SSBs per SSB group. The number of SSBs actually transmitted is calculated by the following equation 1.

[ equation 1]

N # of the SSB actually transmitted

Here, when the number of ATTS per SSB group is indicated, it may be assumed that ATSSs are sequentially transmitted from the beginning of the SSB group.

Examples 6 to 5

The ATSS may be indicated by indicating information related to SSB group transmission using a bitmap and indicating information on the number of SSBs transmitted in the SSB group using a bit other than the bitmap.

For example, 64 SSBs may be divided into 8 SSB groups, as in type2 of fig. 30(b), and an 8-bit bitmap may be transmitted to inform the UE of information on the SSB groups used for ATSS transmission. When the region capable of transmitting the SSB is defined as type2 of fig. 30(b), there is an advantage in that when the SSB is multiplexed with the slot having the 60kHz subcarrier spacing, the boundary of the SSB group is aligned with the boundary of the slot having the 60kHz subcarrier spacing. Accordingly, when a bitmap is used to indicate whether to use an SSB group, the UE can know whether to transmit SSBs per slot for all subcarrier spacings in a frequency band of 6GHz or higher.

Further, for the ATSS indication, additional information for indicating which SSB of the 8 SSBs in each SSB group is transmitted is required. Therefore, a method of using additional bits to inform information about how many SSBs are used among 8 SSBs included in an SSB group may be used. Here, 3 bits are required to inform information about the number of actually used SSBs among 8 SSBs included in one group, and the corresponding information needs to be equally applied to all SSB groups.

For example, if SSB group #0 and SSB group #1 are indicated by bitmap information and transmission of 3 SSBs in each SSB group is indicated by 3-bit information, SSB group #0 and SSB group #1 include 3 SSBs, respectively and thus the total number of ATSSs is 6. Here, SSBs are arranged in the SSB group sequentially from the position of the foremost candidate SSB.

If the 8-bit bitmap information for indicating the SSB group used is 00000000 (all zeros), an indication method different from that of embodiment 6-5 may be applied. This will be described in detail by embodiment 7 which will be described later.

Examples 6 to 6

The ATSS may be indicated by indicating information on SSB group transmission using a bitmap and indicating information on the number of transmitted SSBs in the SSB group using a bit other than the bitmap.

For example, the total 64 SSBs may be divided into 8 SSB groups, as in type2 of fig. 30(b), and an 8-bit bitmap may be transmitted to inform the UE of information on the SSB groups for ATSS transmission. When the region capable of transmitting the SSB is defined as type2 as in fig. 30(b), there is an advantage in that when the SSB is multiplexed with the slot having the 60kHz subcarrier spacing, the boundary of the SSB group is aligned with the boundary of the slot having the 60kHz subcarrier spacing. Accordingly, when a bitmap is used to indicate whether to use an SSB group, the UE can know whether to transmit SSBs per slot for all subcarrier spacings in a frequency band of 6GHz or higher.

For the ATSS indication, additional information for indicating which SSB of the 8 SSBs in each SSB group is transmitted is required. Therefore, a method of using an additional bit to inform information about how many SSBs are used among 8 SSBs included in an SSB group may be used. 6 bits are required to inform information about the number of SSBs actually used among the 64 SSBs, and the number of ATSSs transmitted in the SSB group can be identified using the corresponding information. This is calculated by the following equation 2.

[ equation 2]

The # - [ B ] of the SSB group actually transmitted

(SSB group index defining actual transmission: AT SSB group # 0-AT SSB group # B-1)

N # of the SSB actually transmitted

Here, when the number of ATSSs per SSB group is indicated, it may be assumed that the ATSSs are sequentially transmitted from the beginning of each SSB group.

If the 8-bit bitmap information for indicating the SSB group used is 00000000 (all zeros), an indication method different from that of embodiment 6-6 may be applied. This will be described in detail by embodiment 7 which will be described later.

Examples 6 to 7

The ATSS may be indicated by indicating information related to SSB group transmission using a bitmap and indicating whether to send SSBs in the SSB group using a bit other than the bitmap.

For example, the total 64 SSBs may be divided into 8 SSB groups as in type2 of fig. 30(b) and an 8-bit bitmap may be sent to inform the UE of information about the SSB groups used for ATSS transmission. When the region capable of transmitting the SSB is defined as type2 of fig. 30(b), there is an advantage in that when the SSB is multiplexed with the slot having the 60kHz subcarrier spacing, the boundary of the SSB group is aligned with the boundary of the slot having the 60kHz subcarrier spacing. Accordingly, when a bitmap is used to indicate whether to use an SSB group, the UE can know whether to transmit an SSB per slot for all subcarrier intervals in a band of 6GHz or higher.

Further, for the ATSS indication, additional information for indicating which SSB of the 8 SSBs in each SSB group is transmitted is required. Therefore, the bitmap can be used to inform information about which SSBs of the 8 SSBs included in the SSB group are transmitted. In this case, 8 bits are required because bitmap information on 8 SSBs included in an SSB group needs to be transmitted, and the corresponding information needs to be equally applied to all SSB groups. For example, if transmission using the SSB group #0 and the SSB group #1 is indicated by a bitmap for the SSB group and the first and fifth SSBs in the SSB group is indicated by a bitmap for the SSB group, the first and fifth SSBs in the SSB group #0 and the SSB group #1 are transmitted, and thus the total number of ATSSs is 4.

If the 8-bit bitmap information for indicating the SSB group used is 00000000 (all zeros), an indication method different from that of embodiments 6-7 may be applied. This will be described in detail by embodiment 7 which will be described later.

When ATSS is indicated as in embodiments 6-1 to 6-7, an offset in the 5ms window with respect to the SSB position may also be indicated. In addition, the UE may assume that there is no ATSS for the duration corresponding to the indicated offset. Meanwhile, although the cells included in the cell list transmitted to the UE may use the above-described indication methods of embodiments 6-1 to 6-7, a default format for the case of detecting a cell not included in the cell list may be defined. Further, a procedure for re-confirming ATSS information indicated to the UE through RMSI or OSI through UE-specific RRC signaling may be required. For example, when an SSB group including ATSS is indicated using 8 bits and then ATSS indexes in the indicated SSB group are indicated using 8 bits as in embodiment 6-7, a procedure for re-confirming ATSS using a full bitmap through RRC signaling may be performed for confirmation similarly to embodiment 6-2.

7. Method for indicating ATSS under specific conditions

Embodiment 7 describes an ATSS indication mechanism that can be used when the 8-bit bitmap for SSB group indication is 00000000 (all zeros) in embodiments 6-5 to 6-7 described above, as shown in fig. 31. Here, the remaining bits except for 8 bits for SSB group indication may be used for ATSS indication. That is, referring to fig. 31, a bit included in a "bit actually transmitting an SSB indication" part in an SSB group may be used. The specific ATSS indication mechanism is described by examples 7-1 to 7-4.

Example 7-1

The location of the ATSS may be defined in the form of a pattern. When the number of bits in the "bits actually transmitting SSB indication" part in SSB group of fig. 31 is K, K bits may be used to indicate 2 at most^KAt least one of the patterns. When the pattern is indicated, the UE may operate assuming that the ATSS is transmitted in the pattern.

Example 7-2

The SSB group for the ATSS among the SSB groups is indicated to the UE using K bits as a bitmap. The UE operates assuming that all 8 SSBs that can be included in the indicated SSB group are ATSSs.

Examples 7 to 3

The SSBs, which is an ATSS, among the initial K SSBs is indicated to the UE using K bits as a bitmap. The UE operates assuming that the SSB is repeatedly transmitted in a 5ms window using the indicated K ATSS information as one pattern in a corresponding manner.

Examples 7 to 4

K bits may be used to indicate the ATSS periodicity and the total number of ATSSs sent. Some of the K bits are used to indicate the ATSS periodicity and the remaining bits are used to indicate the number of ATSSs. Accordingly, the UE can acquire location information of the ATSS through the ATSS periodicity and information on the number of ATSSs.

When ATSS is indicated as in embodiments 7-1 to 7-4, an offset relative to the SSB position within a 5ms window may also be indicated. The UE may assume that there is no ATSS for the duration corresponding to the indicated offset.

Referring to fig. 32, the communication apparatus 3300 includes a processor 3310, a memory 3320, an RF module 3330, a display module 3340, and a User Interface (UI) module 3350.

For simplicity of description, part of the modules may be omitted from the communication apparatus 3300. The communication device 3300 may have some modules added or omitted. In addition, the modules of the communication apparatus 3300 may be divided into more modules. The processor 3310 is configured to perform operations according to the embodiments of the present invention described previously with reference to the drawings. In particular, for detailed operations of the processor 3310, reference may be made to the descriptions of fig. 1 to 31.

The memory 3320 is connected to the processor 3310 and stores an Operating System (OS), applications, program codes, data, and the like. The RF module 3330 connected to the processor 3310 up-converts a baseband signal into an RF signal or down-converts an RF signal into a baseband signal. To this end, the RF module 3330 performs digital-to-analog conversion, amplification, filtering, and up-conversion, or inversely performs the processes. In the present invention, the RF module 3330 may be referred to as a transceiver. The display module 3340 is connected to the processor 3310 and displays various types of information. The display module 3340 may be configured as, but is not limited to, known components such as a Liquid Crystal Display (LCD), a Light Emitting Diode (LED) display, and an Organic Light Emitting Diode (OLED) display. The UI module 3350 is connected to the processor 3310 and may be configured with a combination of well-known user interfaces such as a keyboard, a touch screen, and the like.

The embodiments of the invention described above are defined combinations of elements and features of the invention. Elements or features may be considered selectively unless otherwise specified. Each element or feature may be practiced without being combined with other elements or features. Further, the embodiment of the present invention may be configured by combining some of the elements and/or features. The order of operations described in the embodiments of the present invention may be rearranged. Some of the structures or features of any one embodiment may be included in another embodiment and may be replaced with corresponding structures or features of another embodiment. It is obvious to those skilled in the art that claims that are not explicitly cited in each other in the appended claims may be presented in combination as an embodiment of the present invention or included as a new claim by subsequent amendment after the application is filed.

The described specific operations performed by the BS may be performed by an upper node of the BS. That is, it is apparent that, in a network composed of a plurality of network nodes including the BS, various operations performed for communication with the UE may be performed by the BS or by a network node other than the BS. The term "BS" may be replaced by the terms "fixed station", "node B", "evolved node B (enodeb or eNB)", "Access Point (AP)", and the like.

Embodiments of the invention may be implemented by various means, such as hardware, firmware, software, or combinations thereof. In a hardware configuration, the method according to an exemplary embodiment of the present invention may be implemented by one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), digital signal processing devices (DSDPs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or the like.

In a firmware or software configuration, embodiments of the present invention may be implemented in the form of modules, steps, functions, and the like, which perform the functions or acts described above. The software codes may be stored in memory units and executed by processors. The memory unit is located inside or outside the processor, and may transmit and receive data to and from the processor via various known means.

It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms than those herein set forth without departing from the spirit or essential characteristics of the invention. The embodiments described above are therefore to be construed in all aspects as illustrative and not restrictive. The scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the description above, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Industrial applicability

Although the method for transmitting and receiving a synchronization signal block and the apparatus therefor have been described by emphasizing an example in which it is applied to a 5G new RAT system, the method and apparatus may be applied to various mobile communication systems other than the 5G new RAT system.

Claims

1. A method for receiving a synchronization signal block, SSB, by a user terminal, UE, in a wireless communication system, the method comprising:

receiving at least one SSB mapped to 4 symbols respectively,

wherein the first region and the second region for the candidate SSB in which the at least one SSB can be received are allocated in a time period including a plurality of symbols,

wherein the number of symbols between the first region and the second region is the same as the number of symbols before the first region within the time period,

wherein the number of symbols before the first region and the number of symbols after the second region are the same during the time period,

wherein the period is arranged 4 times consecutively and 4 times consecutively after a predetermined time within a half frame,

wherein, in the time domain, the length of the predetermined time is the same as the length of the time period,

wherein the time period is configured to be 2 slots for a subcarrier spacing of 120kHz, an

Wherein the time period is configured to be 4 slots for a subcarrier spacing of 240 kHz.

2. The method of claim 1, wherein the candidate SSBs are arranged consecutively by a first number in each of the first and second regions.

3. The method of claim 1, wherein the number of symbols is 4 for a subcarrier spacing of 120 kHz.

4. The method of claim 1, wherein a frequency band in which the UE is configured to operate is equal to or greater than 6 GHz.

5. A user terminal, UE, configured to receive a synchronization signal block, SSB, in a wireless communication system, the UE comprising:

a transceiver; and

at least one processor coupled with the transceiver,

wherein the at least one processor is configured to receive at least one SSB mapped to 4 symbols, respectively,

6. A method for transmitting a synchronization signal block, SSB, by a base station in a wireless communication system, the method comprising:

transmitting at least one SSB mapped to 4 symbols respectively,

wherein a first region and a second region for candidate SSBs in which the at least one SSB can be transmitted are allocated in a time period including a plurality of symbols,

7. A base station for transmitting a synchronization signal block, SSB, in a wireless communication system, the base station comprising:

a transceiver; and

at least one processor coupled with the transceiver,

wherein the at least one processor is configured to transmit at least one SSB mapped to 4 symbols, respectively,