Method for transceiving downlink channel and apparatus therefor

Abstract

Disclosed are a method for receiving a downlink channel and an apparatus thereof. Particularly, the method includes receiving a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH), acquiring an indicator indicating a spacing between subcarriers in the downlink channel through the PBCH, and receiving the downlink channel based on the spacing of the subcarriers. The spacing between the subcarriers indicated by the value of the indicator can be different according to a frequency band in which the terminal operates.

Description

[0001] This application is a divisional application of patent application No. 201880017831.6 (PCT / KR2018 / 006790), filed with the China Patent Office on September 12, 2019, with an international application date of June 15, 2018, entitled "Method and Apparatus for Receiving and Receiving Downlink Channels". Technical Field

[0002] This disclosure relates to methods and apparatus for transmitting and receiving downlink (DL) channels, and more specifically, to methods and apparatus for transmitting and receiving DL channels based on subcarrier intervals for DL ​​bandwidth indicated by the content of a Physical Broadcast Channel (PBCH) included in a Synchronization Signal Block (SSB). Background Technology

[0003] As current trends dictate that more and more communication devices require greater bandwidth, a next-generation fifth-generation (5G) system is needed to provide enhanced wireless broadband communication compared to traditional LTE systems. In next-generation 5G systems, communication scenarios are categorized into enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC), among others.

[0004] Here, eMBB is a next-generation mobile communication scenario characterized by high spectral efficiency, high user experience data rate, and high peak data rate; URLLC is a next-generation mobile communication scenario characterized by ultra-high reliability, ultra-low latency, and ultra-high availability (e.g., vehicle-to-everything (V2X), emergency services, and remote control); and mMTC is a next-generation mobile communication scenario characterized by low cost, low energy, short packet size, and massive connectivity (e.g., Internet of Things (IoT)). Summary of the Invention

[0005] Technical issues

[0006] This disclosure aims to provide methods and apparatus for transmitting and receiving downlink (DL) channels.

[0007] Those skilled in the art will understand that the purposes achievable by this disclosure are not limited to those specifically described above, and that the above and other purposes achievable by this disclosure will become clear from the following detailed description.

[0008] Technical solution

[0009] According to embodiments of this disclosure, a method for a user equipment (UE) to receive a downlink channel in a wireless communication system may include: receiving a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH); obtaining an indicator from the PBCH indicating a subcarrier spacing for the downlink channel; and receiving the downlink signal based on the subcarrier spacing. The indicator may indicate different subcarrier spacings depending on the frequency band in which the UE operates.

[0010] Here, the indicator can be 1 bit.

[0011] In addition, if the frequency band in which the UE operates exceeds a certain value, the subcarrier spacing indicated by the indicator can be 60kHz or 120kHz.

[0012] In addition, if the frequency band in which the UE operates is lower than a certain value, the subcarrier spacing indicated by the indicator can be 15 kHz or 30 kHz.

[0013] In addition, the downlink channel can carry system information or messages for initial access.

[0014] Furthermore, the subcarrier spacing used for system information and the subcarrier spacing used for initial access messages can be equal.

[0015] According to this disclosure, a UE for receiving a downlink channel in a wireless communication system may include: a transceiver configured to transmit and receive wireless signals from a BS; and a processor configured to: control the transceiver to receive a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH); obtain an indicator from the PBCH indicating a subcarrier spacing for the downlink channel; and control the transceiver to receive downlink signals based on the subcarrier spacing. The indicator may indicate different subcarrier spacings depending on the frequency band in which the UE operates.

[0016] Here, the indicator can be 1 bit.

[0017] In addition, if the frequency band in which the UE operates exceeds a certain value, the subcarrier spacing indicated by the indicator can be 60kHz or 120kHz.

[0018] In addition, if the frequency band in which the UE operates is lower than a certain value, the subcarrier spacing indicated by the indicator can be 15 kHz or 30 kHz.

[0019] In addition, the downlink channel can carry system information or messages for initial access.

[0020] Furthermore, the subcarrier spacing used for system information and the subcarrier spacing used for initial access messages can be equal.

[0021] According to embodiments of this disclosure, a method for transmitting a downlink channel by a BS in a wireless communication system may include: transmitting a synchronization signal block (SSB) comprising a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH); and transmitting the downlink signal based on a subcarrier spacing indicator transmitted on the PBCH. The subcarrier spacing indicator may indicate different subcarrier spacings depending on the frequency band in which the UE operates.

[0022] According to this disclosure, a BS for transmitting downlink channels in a wireless communication system may include: a transceiver configured to transmit wireless signals to and receive wireless signals from a UE; and a processor configured to: control the transceiver to transmit a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH), and to control the transceiver to transmit downlink signals based on a subcarrier spacing indicator transmitted on the PBCH. The subcarrier spacing indicator may indicate different subcarrier spacings depending on the frequency band in which the UE operates.

[0023] Beneficial effects

[0024] According to this disclosure, the DL channel is received based on the subcarrier spacing for the DL channel indicated by the synchronization signal block (SSB). Therefore, it is also possible to receive the DL channel using a parameter set different from the parameter set of the SSB.

[0025] Those skilled in the art will understand that the effects achievable through this disclosure are not limited to those specifically described above, and that other effects of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings. Attached Figure Description

[0026] Figure 1 This is a view illustrating the control plane and user plane architecture of the radio interface protocol between a User Equipment (UE) conforming to the 3GPP radio access network standard and the evolved UMTS Terrestrial Radio Access Network (E-UTRAN).

[0027] Figure 2 This is a view illustrating the physical channel in a 3GPP system and the general signal transmission method using that physical channel.

[0028] Figure 3 This is a view illustrating the radio frame structure used to transmit synchronization signals (SS) in a Long Term Evolution (LTE) system.

[0029] Figure 4This is a view illustrating an exemplary time slot structure available in the New Radio Access Technology (NR).

[0030] Figure 5 This is a view illustrating an exemplary connection scheme between a transceiver unit (TXRU) and an antenna unit.

[0031] Figure 6 This is an abstract illustration of a hybrid beamforming structure involving the TXRU and the physical antenna.

[0032] Figure 7 This is a view illustrating beam scanning used for synchronizing signals and system information during downlink (DL) transmission.

[0033] Figure 8 This is a view of an exemplary cell in an NR system.

[0034] Figure 9 This is a view cited to describe an embodiment of multiplexing the primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical broadcast channel (PBCH) in a synchronization signal (SS).

[0035] Figures 10 to 14 This is a view that is referenced to describe the methods used to configure SS bursts and SS burst sets.

[0036] Figure 15 It is a view cited to describe the method used to indicate information about SS indexes and SS transfer times.

[0037] Figures 16 to 33 This is a view illustrating performance measurement results according to an embodiment of the present disclosure.

[0038] Figures 34 to 36 This is a view cited to describe an embodiment of configuring the bandwidth of the DL common channel.

[0039] Figure 37 This is a block diagram illustrating the components used to implement the transmitting device 10 and receiving device 20 of this disclosure. Detailed Implementation

[0040] The configuration, operation, and other features of this disclosure will be readily understood by referring to the embodiments described in the accompanying drawings. The embodiments of this disclosure set forth herein are examples in which the technical features of this disclosure are applied to a 3rd Generation Partnership Project (3GPP) system.

[0041] Although embodiments of this disclosure are described in the context of Long Term Evolution (LTE) and LTE-Advanced (LTE-A) systems, they are purely exemplary. Therefore, embodiments of this disclosure can be applied to any other communication system, provided the foregoing definitions are valid for that system.

[0042] The term “base station” (BS) can be used to encompass the meanings of the following terms, including Remote Radio Header (RRH), Evolved Node B (eNB or eNode B), Transmitting Point (TP), Receiving Point (RP), Relay Station, etc.

[0043] The 3GPP communication standard defines downlink (DL) physical channels and DL physical signals. Downlink (DL) physical channels correspond to resource elements (REs) carrying information from higher layers. DL physical signals are used in the physical layer and correspond to REs that do not carry information from higher layers. For example, the Physical Downlink Shared Channel (PDSCH), Physical Broadcast Channel (PBCH), Physical Multicast Channel (PMCH), Physical Control Format Indicator Channel (PCFICH), Physical Downlink Control Channel (PDCCH), and Physical Hybrid ARQ Indicator Channel (PHICH) are defined as DL physical channels, and the Reference Signal (RS) and Synchronization Signal (SS) are defined as DL physical signals. RS, also known as pilot signals, are signals with predetermined special waveforms 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 and UL physical signals. Uplink (UL) physical channels correspond to Request Arrays (REs) carrying information from higher layers, while UL physical signals are used in the physical layer and correspond to REs that do not carry information from higher layers. For example, the Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), and Physical Random Access Channel (PRACH) are defined as UL physical channels, while the Demodulation Reference Signal (DMRS) for UL control / data signals and the Sounding Reference Signal (SRS) for UL channel measurements are defined as UL physical signals.

[0044] In this disclosure, PDCCH / PCFICH / PHICH / PDSCH refers to a set of time-frequency resources or a set of REs carrying downlink control information (DCI) / control format indicator (CFI) / DL positive acknowledgment / negative acknowledgment (ACK / NACK) / DL data. Furthermore, PUCCH / PUSCH / PRACH refers to a set of time-frequency resources or a set of REs carrying UL control information (UCI) / UL data / random access signals. Specifically, in this disclosure, 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 / PUCCH RE / PUSCH RE / PRACH RE or PDCCH resource / PCFICH resource / PHICH resource / PDSCH resource / PUCCH resource / PUSCH resource / PRACH resource. In the following text, if the UE transmits PUCCH / PUSCH / PRACH, it means that UCI / UL data / random access signals are transmitted on or through PUCCH / PUSCH / PRACH. Furthermore, if the gNB transmits PDCCH / PCFICH / PHICH / PDSCH, it means that DCI / control information is transmitted on or through PDCCH / PCFICH / PHICH / PDSCH.

[0045] Hereinafter, the orthogonal frequency division multiplexing (OFDM) symbols / carriers / subcarriers / REs that are assigned to or configured for CRS / DMRS / CSI-RS / SRS / UE-RS are referred to as CRS / DMRS / CSI-RS / SRS / UE-RS symbols / carriers / subcarriers / REs. For example, the OFDM symbol that assigns or configures the tracking RS (TRS) to or configures the TRS is called a TRS symbol, the subcarrier that assigns or configures the TRS to or configures the TRS is called a TRS subcarrier, and the RE that assigns or configures the TRS to or configures the TRS is called a TRS RE. Furthermore, a subframe configured to transmit a TRS is called a TRS subframe. Additionally, a subframe carrying a broadcast signal is called a broadcast subframe or PBCH subframe, and a subframe carrying a synchronization signal (SS) (e.g., the primary synchronization signal (PSS) and / or the secondary synchronization signal (SSS)) is called an SS subframe or a PSS / SSS subframe. The OFDM symbol / subcarrier / RE to which a PSS / SSS is assigned or configured is called a PSS / SSS symbol / subcarrier / RE.

[0046] In this disclosure, CRS port, UE-RS port, CSI-RS port, and TRS port refer to antenna ports configured to transmit CRS, UE-RS, CSI-RS, and TRS, respectively. Antenna ports configured to transmit CRS can be distinguished from each other by the location of REs occupied by CRS; antenna ports configured to transmit UE-RS can be distinguished from each other by the location of REs occupied by UEs; and antenna ports configured to transmit CSI-RS can be distinguished from each other by the location of REs occupied by CSI-RS. Therefore, the terms CRS / UE-RS / CSI-RS / TRS port also refer to the pattern of REs occupied by CRS / UE-RS / CSI-RS / TRS in a predetermined resource area.

[0047] Figure 1 The diagram illustrates the control plane and user plane protocol stacks in the radio interface protocol architecture between a User Equipment (UE) conforming to the 3GPP radio access network standard and the evolved UMTS Terrestrial Radio Access Network (E-UTRAN). The control plane is the path through which the UE and E-UTRAN send control messages to manage calls, while the user plane is the path through which data generated from the application layer, such as voice data or Internet packet data, is sent.

[0048] At Layer 1 (L1), the Physical (PHY) layer provides information delivery services to its higher-level, Media Access Control (MAC) layer. The Physical layer connects to the MAC layer via a transport channel. The transport channel transmits data between the MAC and Physical layers. Data is transmitted on the physical channel between the physical layers of the transmitter and receiver. This 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 and with Single Carrier Frequency Division Multiple Access (SC-FDMA) for the uplink.

[0049] The MAC layer at Layer 2 (L2) provides services to its higher-level Radio Link Control (RLC) layer via logical channels. The RLC layer at L2 supports reliable data transmission. RLC functionality can be implemented within the function blocks of the MAC layer. The Packet Data Convergence Protocol (PDCP) layer at L2 performs header compression to reduce unnecessary control information and thus efficiently transmits Internet Protocol (IP) packets, such as IP version 4 (IPv4) or IP version 6 (IPv6) packets, via a narrow-bandwidth air interface.

[0050] The Radio Resource Control (RRC) layer, located at the lowest part of Layer 3 (or L3), is defined only on the control plane. The RRC layer controls the configuration, reconfiguration, and release of radio bearers (RBs), logical channels, transport channels, and physical channels. Radio bearers refer to the services provided at L2 for data transmission between the UE and the E-UTRAN. For this purpose, the RRC layers of the UE and E-UTRAN exchange RRC messages. If an RRC connection has already been established between the UE and the E-UTRAN's RRC layers, the UE is in RRC connected mode; otherwise, the UE is in RRC idle mode. Above the RRC layer, the Non-Access Stratum (NAS) performs functions including session management and mobility management.

[0051] Downlink transport channels used for transmitting data from E-UTRAN to UE include the Broadcast Channel (BCH) carrying system information, the Paging Channel (PCH) carrying paging messages, and the Downlink Shared Channel (SCH) carrying user traffic or control messages. Downlink multicast traffic or control messages, or downlink broadcast traffic or control messages, can be transmitted on the downlink SCH or a separately defined downlink multicast channel (MCH). Uplink transport channels used for transmitting data from UE to E-UTRAN include the Random Access Channel (RACH) carrying initial control messages and the uplink SCH carrying user traffic or control messages. Logical channels defined above transport channels and mapped to transport channels include the Broadcast Control Channel (BCCH), Paging Control Channel (PCCH), Common Control Channel (CCCH), Multicast Control Channel (MCCH), and Multicast Service Channel (MTCH).

[0052] Figure 2 The diagram illustrates a physical channel in a 3GPP system and a general method for transmitting signals on that physical channel.

[0053] refer to Figure 2 When the UE is powered on or enters a new cell, the UE performs an initial cell search (S201). The initial cell search involves obtaining synchronization with the eNB. Specifically, the UE synchronizes its timing with the eNB and obtains the cell identifier (ID) and other information by receiving the primary synchronization channel (P-SCH) and secondary synchronization channel (S-SCH) from the eNB. The UE can then obtain information broadcast in the cell by receiving the physical broadcast channel (PBCH) from the eNB. During the initial cell search, the UE can monitor the DL channel status by receiving the downlink reference signal (DL RS).

[0054] After the initial cell search, the UE can obtain detailed system information by receiving the Physical Downlink Control Channel (PDCCH) and the Physical Downlink Shared Channel (PDSCH) based on the information included in the PDCCH (S202).

[0055] If the UE initially accesses the eNB or does not have radio resources for signal transmission to the eNB, the UE may perform a random access procedure with the eNB (S203 to S206). During the random access procedure, the UE may transmit a predetermined sequence as a preamble on the Physical Random Access Channel (PRACH) (S203 and S205), and may receive response messages to the preamble on the PDCCH and the PDSCH associated with the PDCCH (S204 and S206). In the case of a contention-based RACH, the UE may additionally perform a contention resolution procedure.

[0056] Following the above process, the UE can receive PDCCH and / or PDSCH from the eNB (S207) and transmit the Physical Uplink Shared Channel (PUSCH) and / or Physical Uplink Control Channel (PUCCH) to the eNB (S208), which is the general DL and UL signal transmission process. Specifically, the UE receives Downlink Control Information (DCI) on the PDCCH. Here, DCI includes control information, such as resource allocation information for the UE. Different DCI formats are defined according to different uses of DCI.

[0057] Control information transmitted by the UE to the eNB on the UL or received by the UE from the eNB on the DL includes: DL / UL positive / negative acknowledgment (ACK / NACK) signals, channel quality indicator (CQI), precoding matrix index (PMI), rank indicator (RI), etc. In 3GPP LTE systems, the UE can transmit control information such as CQI, PMI, RI, etc. on the PUSCH and / or PUCCH.

[0058] Figure 3 This diagram illustrates the radio frame structure used for transmitting synchronization signals (SS) in an LTE system. Specifically, Figure 3 The diagram illustrates the radio frame structure used to transmit synchronization signals and PBCH in Frequency Division Duplex (FDD). Figure 3 Part (a) shows the location of the SS and PBCH transmission in a radio frame configured with a normal cyclic prefix (CP) and Figure 3 Section (b) shows the location where the SS and PBCH are transmitted in a radio frame configured by the extended CP.

[0059] Reference Figure 3A more detailed description of SS. SS is categorized into Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS). PSS is used to obtain time-domain synchronization, such as OFDM symbol synchronization, time slot synchronization, and / or frequency-domain synchronization. Furthermore, SSS is used to obtain cell frame synchronization, cell group ID, and / or CP configuration (i.e., information indicating whether a normal CP or an extended CP is used). Reference Figure 4 The PSS and SSS are transmitted via two OFDM symbols in each radio frame. Specifically, considering the 4.6 ms GSM (Global System for Mobile Communications) frame length, the SS is transmitted in the first time slot of each of subframes 0 and 5, which facilitates inter-radio access technology (RAT) measurements. In particular, the PSS is transmitted in the last OFDM symbol of each of the first time slots of subframe 0 and subframe 5. And, the SSS is transmitted in the second to last OFDM symbols of each of the first time slots of subframe 0 and subframe 5. The boundaries of the corresponding radio frames can be detected via the SSS. The PSS is transmitted in the last OFDM symbol of the corresponding time slot, and the SSS is transmitted in the OFDM symbol immediately preceding the OFDM symbol in which the PSS is transmitted. According to the SS transmission diversity scheme, only a single antenna port is used. However, the transmission diversity scheme used for the SS standard is not separately defined in the current standard.

[0060] refer to Figure 3 By detecting the PSS (Personal Sequence Segment), the UE can determine whether the corresponding subframe is subframe 0 or subframe 5, because the PSS is sent every 5 ms. However, the UE cannot determine whether the subframe is subframe 0 or subframe 5. That is, frame synchronization cannot be obtained solely from the PSS. The UE detects the boundary of a radio frame by detecting SSSs that are sent twice within a radio frame using different sequences.

[0061] After demodulating the DL signal by performing the cell search procedure using PSS / SSS and determining the time and frequency parameters required to perform UL signal transmission at the precise time, the UE is able to communicate with the eNB only after obtaining the system information required for the UE's system configuration from the eNB.

[0062] The system information configuration includes a Master Information Block (MIB) and a System Information Block (SIB). Each SIB includes a set of function-related parameters and is classified into MIB, SIB Type 1 (SIB1), SIB Type 2 (SIB2), and SIB3 through SIB8 based on the parameters included.

[0063] The MIB includes the most frequently transmitted parameters, which are essential for the UE's initial access to the network served by the eNB. The UE can receive the MIB via a broadcast channel (e.g., PBCH). The MIB includes the downlink system bandwidth (DL BW), PHICH configuration, and system frame number (SFN). Therefore, the UE can explicitly learn about the DL BW, SFN, and PHICH configuration by receiving the PBCH. On the other hand, the UE can implicitly learn about the number of transmit antenna ports of the eNB. This information about the number of transmit antennas of the eNB is implicitly signaled by masking (e.g., XOR operation) the sequence corresponding to the number of transmit antennas to a 16-bit Cyclic Redundancy Check (CRC) used to detect errors in the PBCH.

[0064] SIB1 includes not only time-domain scheduling information about other SIBs, but also parameters necessary to determine whether a particular cell is suitable for cell selection. The UE receives SIB1 via broadcast signaling or dedicated signaling.

[0065] The UE can obtain the DL carrier frequency and corresponding system bandwidth through the MIB carried by the PBCH. It can also obtain the UL carrier frequency and corresponding system bandwidth through the system information corresponding to the DL signal. After receiving the MIB, if no valid system information is stored in the corresponding cell, the UE applies the DL BW value included in the MIB to the UL bandwidth until it receives System Information Block Type 2 (SIB2). For example, if the UE obtains SIB2, it can identify the entire UL system bandwidth available for UL transmission through the UL carrier frequency and UL bandwidth information included in SIB2.

[0066] In the frequency domain, PSS / SSS and PBCH are transmitted regardless of the total of 6 RBs (i.e., the actual system bandwidth relative to the 3 RBs to the left and 3 RBs to the right of the DC subcarrier within the corresponding OFDM symbol). In other words, PSS / SSS and PBCH are transmitted only across the 72 subcarriers. Therefore, the UE is configured to detect or decode SS and PBCH regardless of the downlink transmission bandwidth configured for the UE.

[0067] After completing the initial cell search, the UE can perform a random access procedure to complete access to the eNB. For this purpose, the UE sends a preamble via the PRACH (Physical Random Access Channel) and can receive response messages in response to the preamble via the PDCCH and PDSCH. In the case of contention-based random access, it can send an additional PRACH and perform contention resolution procedures, such as the PDCCH and the corresponding PDSCH.

[0068] After performing the above process, as a general UL / DL signal transmission process, the UE is able to perform PDCCH / PDSCH reception and PUSCH / PUCCH transmission.

[0069] The random access procedure is also known as the random access channel (RACH) procedure. Random access procedures are used for various purposes, including initial access, UL synchronization adjustment, resource allocation, handover, etc. Random access procedures are categorized into contention-based procedures and dedicated (i.e., non-contention-based) procedures. Typically, contention-based random access procedures are used for initial access. On the other hand, dedicated random access procedures are restricted to use for handover, etc. When performing a contention-based random access procedure, the UE randomly selects the RACH preamble sequence. Therefore, multiple UEs can simultaneously transmit the same RACH preamble sequence. As a result, a contention resolution process is required afterward. Conversely, when performing a dedicated random access procedure, the UE uses a RACH preamble sequence specifically allocated to the UE by the eNB. Therefore, the UE can perform the random access procedure without conflicting with other UEs.

[0070] The contention-based random access procedure comprises the four steps described below. The messages sent via these four steps can be referred to in this invention as messages (Msg) 1 to 4, respectively.

[0071] - Step 1: RACH Precursor (via PRACH) (UE to eNB)

[0072] - Step 2: Random Access Response (RAR) (via PDCCH and PDSCH (eNB to UE))

[0073] - Step 3: Layer 2 / Layer 3 message (via PUSCH) (UE to eNB)

[0074] - Step 4: Contention Resolution Message (eNB to UE)

[0075] On the other hand, the dedicated random access procedure includes the three steps described below. The messages sent via these three steps can be referred to in this invention as messages (Msg) 0 to 2, respectively. As part of the random access procedure, it can also perform uplink transmissions corresponding to the PAR (i.e., step 3). The dedicated random access procedure can be triggered using a PDCCH (hereinafter, PDCCH command), which is used by the eNB to indicate the transmission of the RACH preamble.

[0076] - Step 0: RACH preamble assignment via dedicated signaling (eNB to UE)

[0077] - Step 1: RACH Precursor (via PRACH) (UE to eNB)

[0078] - Step 2: Random Access Response (RAR) (via PDCCH and PDSCH) (eNB to UE)

[0079] After transmitting the RACH preamble, the UE attempts to receive a Random Access Response (RAR) in a preconfigured time window. Specifically, the UE attempts to detect a PDCCH with RA-RNTI (Random Access RNTI) (hereinafter, RA-RNTI PDCCH) in the time window (for example, a CRC masked with RA-RNTI in the PDCCH). If the RA-RNTI PDCCH is detected, the UE checks whether there is an RAR for the UE in the PDSCH corresponding to the 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 (for example, temporary Cell-RNTI, TC-RNTI), and the like. The UE can perform UL transmission (for example, Message 3) according to the resource allocation information and the TA value included in the RAR. HARQ is applied to the UL transmission corresponding to the RAR. Specifically, the UE can receive reception response information (for example, PHICH) corresponding to Message 3 after transmitting Message 3.

[0080] A random access preamble (i.e., RACH preamble) consists of a cyclic prefix of length TCP and a sequence part of length TSEQ. TCP and TSEQ depend on the frame structure and random access configuration. The preamble format is controlled by higher layers. The RACH preamble is transmitted in a UL subframe. The transmission of the random access preamble is limited to specific time resources and frequency resources. These resources are referred to as PRACH resources. To match index 0 with the lower-numbered subframes in the PRB and radio frame, PRACH resources are numbered in ascending order of the subframe number of the radio frame and the PRB in the frequency domain. The random access resources are defined according to the PRACH configuration index (refer to the 3GPP TS 36.211 standard document). The RACH configuration index is provided by a higher layer signal (transmitted by the eNB).

[0081] In LTE / LTE-A systems, for preamble formats 0 to 3 and preamble format 4, the subcarrier spacing of the random access preamble (i.e., RACH preamble) is specified as 1.25 kHz and 7.5 kHz respectively (refer to 3GPP TS 36.211).

[0082] <OFDM parameter set>

[0083] The new RAT system employs an OFDM transmission scheme or a similar scheme. The new RAT system can use OFDM parameters different from LTE OFDM parameters. Alternatively, the new RAT system can follow the parameter set of traditional LTE / LTE-A but with a larger system bandwidth (e.g., 100 MHz). Or, a single cell can support multiple parameter sets. That is, UEs operating with different parameter sets can coexist within a single cell.

[0084] <Subframe Structure>

[0085] In 3GPP LTE / LTE-A systems, radio frames are 10 ms (307200 Ts) long and consist of 10 equal-sized subframes (SFs). The 10 SFs of a radio frame can be assigned numbers. Ts represents the sampling time and is expressed as Ts = 1 / (2048...). (15kHz). Each SF (Segmented Stream) is 1ms long and includes two time slots. A radio frame has 20 time slots, numbered sequentially from 0 to 19. Each time slot is 0.5ms long. The time taken to transmit an SF is defined as the Transmission Time Interval (TTI). Time resources can be distinguished by radio frame number (or radio frame index), SF number (or SF index), time slot number (or time slot index), etc. TTI refers to the interval in which data can be scheduled. For example, in current LTE / LTE-A systems, there is one UL (Ultimate Rank) or DL ​​(Delegated Rank) transmission opportunity every 1ms, while there are no multiple UL / DL transmission opportunities in time intervals shorter than 1ms. Therefore, in traditional LTE / LTE-A systems, the TTI is 1ms.

[0086] Figure 4 The illustration shows an exemplary time slot structure available in the new radio access technology (NR).

[0087] To minimize data transmission latency, a time-slot structure is considered in fifth-generation (5G) NR systems, in which control channels and data channels are multiplexed using time-division multiplexing (TDM).

[0088] exist Figure 4 In the diagram, the area marked with a slash indicates the transmission area of ​​DL control channels (e.g., PDCCH) carrying DCI, and the black area indicates the transmission area of ​​UL control channels (e.g., PUCCH) carrying UCI. DCI is control information sent by the gNB to the UE and may include information about cell configurations the UE should know, DL-specific information (such as DL scheduling), and UL-specific information (such as UL authorization). Additionally, UCI is control information sent by the UE to the gNB. UCI may include HARQACK / NACK reports for DL ​​data, CSI reports for DL ​​channel states, scheduling requests (SRs), etc.

[0089] exist Figure 4 In this context, symbols with symbol indices 1 to 12 can be used to transmit physical channels carrying DL data (e.g., PDSCH) or physical channels carrying UL data (e.g., PUSCH). According to... Figure 2 The time-slot structure illustrated in the diagram allows for the transmission / reception of DL data and the reception / transmission of UL ACK / NACK for DL ​​data to be performed within a single time slot when DL and UL transmissions occur sequentially within that time slot. Therefore, when errors occur during data transmission, the time spent on data retransmission can be reduced, thereby minimizing the latency of the final data transmission.

[0090] In this time-slot structure, time slots are required to allow the gNB and UE to switch from transmit mode to receive mode or vice versa. For the switch between transmit and receive modes, some OFDM symbols corresponding to the DL-to-UL handover time are configured as guard periods (GP) in the time-slot structure.

[0091] In traditional LTE / LTE-A systems, the DL control channel is multiplexed with the data channel using TDM, and the control channel PDCCH is transmitted distributed across the entire system frequency band. However, in NR, a system bandwidth of at least approximately 100MHz is expected, making it impractical to transmit the control channel across the entire frequency band. If the UE monitors the entire frequency band to receive the DL control channel, this could increase UE battery consumption and reduce efficiency for data transmission / reception. Therefore, the DL control channel can be transmitted centrally or distributed within some frequency bands within the system frequency band, i.e., within the channel bands described in this disclosure.

[0092] In NR systems, the basic transmission unit is a time slot. A time slot duration consists of 14 symbols, each with a normal cyclic prefix (CP), or 12 symbols, each with an extended CP. Furthermore, time slots are time-scaled according to the subcarrier spacing used. That is, as the subcarrier spacing increases, the slot length decreases. For example, given 14 symbols per time slot, if the number of time slots in a 10 ms frame is 10 for a 15 kHz subcarrier spacing, then the number of time slots is 20 for a 30 kHz subcarrier spacing and 40 for a 60 kHz subcarrier spacing. The length of OFDM symbols decreases as the subcarrier spacing increases. The number of OFDM symbols per time slot varies depending on whether there is a normal or extended CP and does not change based on the subcarrier spacing. Considering the basic 15-kHz subcarrier spacing and the maximum FFT size of 2048, the basic time unit T in LTE... s Defined as 1 / (15000) 2048 seconds. T s This is also the sampling time for a 15kHz subcarrier spacing. In NR systems, many other subcarrier spacings besides 15kHz are available, and because the subcarrier spacing is inversely proportional to the corresponding time length, the actual sampling time T corresponding to subcarrier spacings greater than 15kHz is... s Become shorter than 1 / (15000) 2048) seconds. For example, the actual sampling time for subcarrier spacing of 30kHz, 60kHz, and 120kHz can be 1 / (2... 15000 2048) seconds, 1 / (4 15000 2048) seconds and 1 / (8 15000 2048 seconds.

[0093] Simulated Beamforming

[0094] For the 5G mobile communication systems under discussion, the use of ultra-high frequency bands, i.e., millimeter-wave bands of 6 GHz or higher, is considered to facilitate the transmission of data to multiple users at high transmission rates over a wide bandwidth. 3GPP refers to this technology as NR, and therefore, in this disclosure, the 5G mobile communication system will be referred to as an NR system. However, millimeter-wave bands have frequency characteristics that cause signal attenuation too rapidly with distance due to the use of excessively high bands. Therefore, NR systems using at least 6 GHz or higher bands employ narrow-beam transmission schemes, where signals are transmitted with concentrated energy in a specific direction rather than omnidirectionally, thereby compensating for rapid propagation attenuation and thus overcoming the reduction in coverage caused by rapid propagation attenuation. However, if service is provided using only a single narrow beam, the service coverage of a gNB becomes narrow, and therefore the gNB provides service with broadband by combining multiple narrow beams.

[0095] As wavelengths shorten in the millimeter band, or millimeter wave (mmW) band, it becomes possible to install multiple antenna elements in the same area. For example, in a two-dimensional (2D) array on a 5 cm × 5 cm panel, a total of 100 antenna elements can be installed at intervals of 0.5λ (wavelength) in the 30 GHz band with wavelengths of approximately 1 cm. Therefore, it is possible to increase coverage or throughput by using multiple antenna elements in the mmW band to increase beamforming gain.

[0096] To form narrow beams in the millimeter band, a primary beamforming scheme is considered where a gNB or UE transmits the same signal with appropriate phase differences through multiple antennas, thereby increasing energy only in a specific direction. Such beamforming schemes include digital beamforming for generating phase differences between digital baseband signals, analog beamforming for generating phase differences between modulated analog signals using time delays (i.e., cyclic shifts), and hybrid beamforming using both digital and analog beamforming. Independent beamforming per frequency resource is possible if a TXRU is provided for each antenna element to allow control over the transmit power and phase of each antenna. However, installing TXRUs for all approximately 100 antenna elements is not cost-efficient. That is, multiple antennas must be used to compensate for the rapid propagation attenuation in the millimeter band, and digital beamforming requires as many RF components (e.g., digital-to-analog converters (DACs), mixers, power amplifiers, and linear amplifiers) as there are antennas. Therefore, implementing digital beamforming in the millimeter band faces the problem of increased communication equipment costs. Therefore, in millimeter-band applications requiring a large number of antennas, analog beamforming or hybrid beamforming is considered. In analog beamforming, multiple antenna elements are mapped to a single TXRU, and the beam direction is controlled by an analog phase shifter. A drawback of this analog beamforming scheme is that it cannot provide frequency-selective beamforming (BF) because only one beam direction can be generated across the entire frequency band. Hybrid BF lies between digital and analog BF, where fewer than Q antenna elements are used with B TXRUs. In hybrid BF, although the number of beam directions varies depending on the connection between the B TXRUs and Q antenna elements, the number of beam directions that can be transmitted simultaneously is limited to B or less.

[0097] Figure 5 This is a view illustrating an exemplary connection scheme between the TXRU and the antenna unit.

[0098] Figure 5 The diagram (a) illustrates the connection between the TXRU and the subarray. In this case, the antenna element is connected to only one TXRU. In contrast, Figure 5 (b) illustrates the connections between the TXRU and all antenna elements. In this case, the antenna elements are connected to all TXRUs. Figure 5 In this context, W represents the phase vector used for multiplication in the analog phase shifter. That is, the direction of the analog beamforming is determined by W. Here, CSI-RS antenna ports can be mapped to TXRUs in a one-to-one or one-to-many correspondence.

[0099] As previously mentioned, since the digital baseband signal to be transmitted or received undergoes signal processing in digital beamforming, signals can be transmitted on multiple beams in multiple directions or received on multiple beams from multiple directions. In contrast, in analog beamforming, the analog signal to be transmitted or received is beamformed in a modulated state. Therefore, it is not possible to transmit signals simultaneously in multiple directions outside the coverage of a single beam or to receive signals in multiple directions outside the coverage of a single beam. gNBs typically rely on broadband transmission or multi-antenna characteristics to communicate with multiple users simultaneously. If a gNB uses an analog beamforming (BF) or a hybrid beamforming (BF) and forms an analog beam in one beam direction, then due to the nature of the analog BF, the gNB can only communicate with users covered in the same analog beam direction. By reflecting the drawbacks caused by the nature of analog or hybrid BFs, a RACH resource allocation and gNB resource utilization scheme according to the present invention is proposed.

[0100] Hybrid Simulation Beamforming

[0101] Figure 6 An abstract illustration of a hybrid beamforming structure involving TXRU and physical antenna.

[0102] For applications using multiple antennas, hybrid baseband arrays (BFs) combining digital and analog BFs have emerged. Analog BFs (or RF BFs) perform precoding (or combination) operations within the RF units. Due to the precoding (combination) in each of the baseband and RF units, hybrid BFs offer performance benefits approaching those of digital BFs while reducing the number of RF chains and DACs (or analog-to-digital converters (ADCs)). For convenience, a hybrid BF structure can be represented using N TXRUs and M physical antennas. The digital BF for L data layers to be transmitted by the transmitter can be represented as an N×L matrix, and then the N converted digital signals are converted to analog signals by TXRUs and undergo an analog BF represented as an M×N matrix. Figure 6 In this context, the number of digital beams is L, and the number of analog beams is N. Furthermore, in NR systems, the gNB is considered to be configured to change the analog beamforming frequency (BF) based on the symbol, in order to more efficiently support BF for UEs located in a specific area. Additionally, when an antenna panel is defined by N TXRUs and M RF antennas, the introduction of multiple antenna panels with independently applicable hybrid BFs is also considered. Therefore, when the gNB uses multiple analog beams, different analog beams may be preferred for signal reception at each UE. Thus, beam sweeping operations are being considered, where, at least for SS, system information, and paging, the gNB changes multiple analog beams based on the symbol in a specific time slot or SF to allow all UEs to have a reception opportunity.

[0103] Figure 7 This is a view illustrating beam sweep for SS and system information during DL transmission. Figure 7 In this context, the physical resource or physical channel for broadcasting system information of a new RAT system is called the xPBCH. Analog beams from different antenna panels can be transmitted simultaneously within a single symbol, and the introduction of a beam reference signal (BRS) for transmission targeting a single analog beam corresponding to a specific antenna panel is under discussion. Figure 7 The diagram illustrates how to measure the channel of each analog beam. A BRS can be defined for multiple antenna ports, and each antenna port of a BRS can correspond to a single analog beam. Unlike BRS, SS or xPBCH can be transmitted for all analog beams included in an analog beam group, ensuring that any UE can successfully receive either SS or xPBCH.

[0104] Figure 8 This is a view of an exemplary cell in an NR system.

[0105] refer to Figure 8 In contrast to traditional LTE wireless communication systems where one eNB forms a cell, NR systems are discussing configurations where multiple TRPs form a cell. If multiple TRPs form a cell, seamless communication is advantageously possible even if the TRP serving the UE is changed, thereby facilitating UE mobility management.

[0106] Compared to LTE / LTE-A systems that transmit PSS / SSS omnidirectionally, consider a method for transmitting signals such as PSS / SSS / PBCH via beam sweeping (BF), in which BF is performed by sequentially switching the beam direction to all directions at the gNB applying millimeter waves. Signal transmission / reception performed by switching beam directions is called beam sweeping or beam scanning. In this disclosure, "beam sweeping" is an action on the transmitting side, and "beam scanning" is an action on the receiving side. For example, if up to N beam directions are available for the gNB, the gNB transmits signals such as PSS / SSS / PBCH in N beam directions. That is, the gNB transmits SS signals such as PSS / SSS / PBCH in each direction by sweeping the beams in directions available to or supported by the gNB. Alternatively, if the gNB is capable of forming N beams, the beams can be grouped, and PSS / SSS / PBCH can be transmitted / received on a group basis. A beam group includes one or more beams. Signals such as PSS / SSS / PBCH transmitted in the same direction can be defined as an SS block (SSB), and multiple SSBs can exist in a cell. If multiple SSBs exist, each SSB can be identified using an SSB index. For example, if PSS / SSS / PBCH are transmitted in 10 beam directions in a system, then PSS / SSS / PBCH transmitted in the same direction can form an SSB, and it can be understood that there are 10 SSBs in the system. In this disclosure, the beam index can be interpreted as the SSB index.

[0107] Now, a method for indicing the time of sending the SS according to embodiments of the present disclosure and a method for configuring DL bandwidth via the SS will be described.

[0108] 1. SS Block Configuration

[0109] If the maximum payload size of the PBCH is 80 bits, then a total of four OFDM symbols can be used for SS block transmission. Simultaneously, the timing positions of the NR-PSS, NR-SSS, and NR-PBCH included in the SSB need to be discussed. In the initial access state, the NR-PBCH can be used as a reference signal for accurate time / frequency tracking. To improve tracking accuracy, it is effective to separate the two OFDM symbols used for the NR-PBCH as much as possible. Therefore, the first and fourth OFDM symbols of the SSB can be used for NR-PBCH transmission. Thus, the second OFDM symbol can be allocated to the NR-PSS, and the third OFDM symbol can be used for the NR-SSS.

[0110] The results of measuring PBCH decoding performance based on the number of REs used for DMRS show that if two OFDM symbols are allocated to the PBCH, 192 REs can be used for DMRS and 384 REs can be used for data. In this case, assuming a PBCH payload size of 64 bits, a coding speed equal to 1 / 12 of the coding speed of the LTE PBCH can be achieved.

[0111] One approach is to map the encoded NR-PBCH bits to REs in the PBCH symbols. However, this method has drawbacks in terms of interference and decoding performance. On the other hand, if the encoded NR-PBCH bits are mapped to REs included in N PBCH symbols, this method can achieve better performance in terms of interference and decoding.

[0112] Meanwhile, a comparison between bits encoded using the same method in two OFDM symbols and bits encoded using different methods in two OFDM symbols shows that the latter offers better performance because the encoded bits have more redundant bits. Therefore, using bits encoded using different methods in two OFDM symbols can be considered.

[0113] Furthermore, NR systems support multiple parameter sets. Therefore, the parameter set used for SSB transmission may differ from the parameter set used for data transmission. Additionally, if different types of channels, such as PBCH and PDSCH, are multiplexed in the frequency domain, spectrum transmission can lead to inter-carrier interference (ICI) and thus performance degradation. To address this issue, a guard frequency can be introduced between PBCH and PDSCH. Furthermore, to reduce the impact of ICI, the network can allocate data RBs such that they are not adjacent to each other.

[0114] However, the aforementioned method is inefficient because a large number of REs must be reserved as guard frequencies. Therefore, reserving one or more subcarriers at the edges as guard frequencies within the PBCH transmission bandwidth may be more efficient. The exact number of reserved REs can be varied depending on the subcarrier spacing of the PBCH. For example, for a 15kHz subcarrier spacing in PBCH transmission, two subcarriers can be reserved at each edge of the PBCH transmission bandwidth. On the other hand, for a 30kHz subcarrier spacing in PBCH transmission, one subcarrier can be reserved.

[0115] refer to Figure 9In part (a), the NR-PBCH is allocated within 288 REs, forming 24 RBs. Simultaneously, since the sequence length of NR-PSS / NR-SSS is 127, 12 RBs are required to transmit NR-PSS / NR-SSS. That is, when configuring the SSB, the SSB is allocated across 24 RBs. Furthermore, it is preferable to allocate the SSB across 24 RBs for RB grid alignment between different parameter sets such as 15, 30, and 60 kHz. Additionally, since it is assumed in NR that a minimum bandwidth of 5 MHz for 25 RBs can be defined with a 15 kHz subcarrier spacing, 24 RBs are used for SSB transmission. Furthermore, the NR-PSS / SSS should be positioned in the middle of the SSB, which may mean that the NR-PSS / SSS is allocated between RBs 7 and 18.

[0116] At the same time, if Figure 9 If the SSB configuration shown in section (a) is configured, problems may occur in the UE's automatic gain control (AGC) operation at subcarrier spacings of 120 kHz and 240 kHz. That is, for subcarrier spacings of 120 kHz and 240 kHz, NR-PSS may not be successfully detected due to AGC operation. In this scenario, changing the SSB configuration can be considered in the following two embodiments.

[0117] (Method 1)PBCH-PSS-PBCH-SSS

[0118] (Method 2)PBCH-PSS-PBCH-SSS-PBCH

[0119] In other words, the PBCH symbol can be positioned at the beginning of the SSB and used as a dummy symbol for AGC operations, enabling the UE to perform AGC operations more reliably.

[0120] At the same time, it can be like Figure 9 The NR-PSS / NR-SSS / NR-PBCH assignments are illustrated in part (b). That is, NR-PSS can be assigned to symbol 0, and NR-SSS can be assigned to symbol 2. NR-PBCH can be assigned to symbols 1 through 3. Here, symbols 1 and 3 can be dedicated to NR-PBCH. In other words, NR-PBCH can be mapped only to symbols 1 and 3, and NR-SSS and NR-PBCH can be mapped together to symbol 2.

[0121] 2. SS Burst Set Configuration

[0122] Figure 10 The diagrams illustrate SS burst sets configured with subcarrier spacing of 120 kHz and 240 kHz, respectively. (Reference) Figure 10 For subcarrier spacing of 120kHz and 240kHz, SS bursts are configured with a predetermined gap every four SS bursts. That is, SSBs are arranged with a symbol period of 0.125ms, used to clear UL transmission every 0.5ms.

[0123] However, a subcarrier spacing of 60 kHz can be used for data transmission in frequency bands of 6 GHz or higher. That is, as... Figure 11 As shown in the diagram, the 60kHz subcarrier spacing used for data transmission and the 120kHz or 240kHz subcarrier spacing used for SSB transmission can be multiplexed in NR.

[0124] At the same time, from Figure 11 As shown in the boxed section, when an SSB with a 120kHz subcarrier spacing is multiplexed with data with a 60kHz subcarrier spacing, the SSB with the 120kHz subcarrier spacing and the GP and DL control regions with the 60kHz subcarrier spacing conflict or overlap with each other. Since conflicts between the SSB and the DL / UL control regions should preferably be avoided, the configuration of the SS burst and SS burst set needs to be modified.

[0125] In this disclosure, two embodiments are proposed to modify the SS burst configuration to avoid the aforementioned problems.

[0126] One embodiment involves changing the positions of SS burst format 1 and SS burst format 2, such as... Figure 12 As shown in the diagram. That is, Figure 11 The SS burst format 1 and SS burst format 2 in the box shown in the figure are swapped, as follows: Figure 12 As illustrated, this is to prevent conflicts between the SSB and DL / UL control areas. In other words, SS burst format 1 is positioned at the beginning of a time slot with a 60kHz subcarrier spacing, and SS burst format 2 is positioned at the end of a time slot with a 60kHz subcarrier spacing.

[0127] The above embodiments can be summarized as follows.

[0128] 1) 120-kHz subcarrier spacing

[0129] - The first OFDM symbol of the candidate SSB has indices {4,8,16,20,32,36,44,48} ​​+ 70 For carrier frequencies greater than 6 GHz, n = 0, 2, 4, 6.

[0130] - The first OFDM symbol of the candidate SSB has indices {2,6,18,22,30,34,46,50} + 70 For carrier frequencies greater than 6 GHz, n = 1, 3, 5, 7.

[0131] 2) 240-kHz subcarrier spacing

[0132] - The first OFDM symbol of the candidate SSB has the index {8,12,16,20,32,36,40,44,64,68,72,76,88,92,96,100} + 140 For carrier frequencies greater than 6 GHz, n = 0, 2.

[0133] - The first OFDM symbol of the candidate SSB has the index {4,8,12,16,36,40,44,48,60,64,68,72,92,96,100,104} + 140 For carrier frequencies greater than 6 GHz, n = 1, 3.

[0134] Another embodiment is to change the SS burst set configuration, such as Figure 13 As illustrated in the diagram. In other words, the SS burst set can be configured such that the starting boundary of the SS burst set is aligned with the starting boundary of the time slot with a 60kHz subcarrier spacing, i.e., matched.

[0135] Specifically, SS bursts are configured using SSBs centralized at 1ms. Therefore, an SS burst with a 120kHz subcarrier spacing has 16 SSBs at 1ms, and an SS burst with a 240kHz subcarrier spacing has 32 SSBs at 1ms. If SS bursts are configured in this way, then for a 60kHz subcarrier spacing, one time slot is allocated as the interval between SS bursts.

[0136] The second embodiment is summarized below.

[0137] 1) 120kHz subcarrier spacing

[0138] The first OFDM symbol of the candidate SSB has the index {4,8,16,20} + 28. n. For carrier frequencies greater than 6 GHz, n = 0,1,2,3,5,6,7,8,10,11,12,13,15,16,17,18.

[0139] 2) 240-kHz subcarrier spacing

[0140] - The first OFDM symbol of the candidate SSB has indices {8,12,16,20,32,36,40,44} + 56 n. For carrier frequencies greater than 6 GHz, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0141] 3. A method for indicating the actual SS / PBCH block transmitted within a 5ms time period.

[0142] Simultaneously, the number of candidate SSB transmissions can be limited based on the network environment. For example, the number of candidates can vary depending on the subcarrier spacing of the SSB deployment. In this case, the location of the actually transmitted SSB can be indicated to the CONNECTED / IDLE mode UE. Here, the actually transmitted SS / PBCH block indicating the location of the actually transmitted SSB indicates what can be used for resource utilization purposes for the serving cell, such as rate matching, and for measuring corresponding resources for neighboring cells.

[0143] Regarding the serving cell, if the UE can accurately determine the untransmitted SSBs, then the UE can determine that it can receive other information, such as paging or data, from the candidate resources of the untransmitted SSBs. For this resource flexibility, it is necessary to accurately indicate the SSBs actually transmitted in the serving cell.

[0144] In other words, since other information such as paging or data may not be received in resources carrying SSBs, the UE needs to know the SSB candidates that are not actually transmitted in order to improve resource utilization efficiency by receiving other data or signals in the untransmitted SSBs.

[0145] Therefore, a 4, 8, or 64-bit full bitmap is needed to accurately indicate the SSBs actually transmitted in the serving cell. The number of bits included in the bitmap can be determined based on the maximum number of SSBs that can be transmitted in each frequency range. For example, to indicate the SSBs actually transmitted in a 5ms time period, 8 bits are needed in the 3GHz to 6GHz frequency range, and 64 bits are needed in the 6GHz or higher frequency range.

[0146] The bits used to indicate the SSB actually transmitted in the serving cell can be defined by the Residual Minimum System Information (RMSI) or other System Information (OSI), and the RMSI / OSI includes configuration information for data or paging. The SS / PBCH block indication is associated with the DL resource configuration, thus it can be concluded that the RMSI / OSI includes information about the actually transmitted SSB.

[0147] Simultaneously, it may be necessary to actually send SS / PBCH block indications of neighboring cells to measure neighboring cells. In other words, for neighboring cell measurements, time synchronization information about neighboring cells is required. When designing an NR system to allow asynchronous transmission between TRPs, the accuracy of the information may vary even if time synchronization information about neighboring cells is known. Therefore, when indicating time information about neighboring cells, the unit of the time information needs to be determined to be information valid for the UE, while assuming asynchronous transmission between TRPs.

[0148] However, if too many cells are listed, the full-bitmap type indicator may excessively increase signaling overhead. Therefore, indicators compressed in various ways can be considered to reduce signaling overhead. Simultaneously, indicators for SSBs transmitted in the serving cell can also be compressed to reduce signaling overhead and measure neighboring cells. In other words, subsequent SS block indicators can be used to indicate the actual SSBs transmitted in neighboring and serving cells. Furthermore, according to the above description, only in the following embodiments, although an SS burst can be a group of SSBs included in a slot on each subcarrier, an SS burst can represent an SSB group including a predetermined number of SSBs, regardless of the slot.

[0149] refer to Figure 14 In one embodiment, if an SS burst includes 8 SSBs, then a total of 8 SS bursts may exist in a 6 GHz or higher frequency band where 64 of the SSBs are available.

[0150] SSBs are grouped into SS bursts to compress the 64-bit bitmap. An 8-bit information can be used instead of the 64-bit bitmap to indicate an SS burst that includes an actual transmitted SSB. If the 8-bit bitmap indicates SS burst #0, then SS burst #0 may include one or more actual transmitted SSBs.

[0151] Here, additional information can be considered to further indicate the number of SSBs sent in each SS burst. The same number of SSBs as indicated by the additional information can be locally present in each SS burst.

[0152] Therefore, the UE can estimate the actual number of SSBs transmitted by combining the number of SSBs actually transmitted in each SS burst indicated by the additional information with a bitmap indicating the SS bursts that include the actual transmitted SSBs.

[0153] For example, we can assume the indications in Table 1 below.

[0154] [Table 1]

[0155] That is, according to [Table 1], it can be determined from the 8-bit bitmap that the SSB is included in SS burst #0, SS burst #1, and SS burst #7, and it can be determined from the additional information that each SS burst includes four SSBs. Therefore, it can be estimated that the SSB will be sent at the first four candidate positions in SS burst #0, SS burst #1, and SS burst #7.

[0156] In addition, unlike the example above, additional information can also be sent in the form of a bitmap, thereby enabling flexibility in the location of SSB transmission.

[0157] For example, information related to SS burst transmission can be indicated by a bitmap, and the SSBs sent in the SS burst can be indicated by other bits.

[0158] In other words, a total of 64 SSBs are divided into 8 SS bursts (i.e., SSB groups), and the SS burst to be used can be indicated to the UE via an 8-bit bitmap. If... Figure 14 The definition of an SS burst is shown below. If an SS burst is multiplexed with a time slot having a 60kHz subcarrier spacing, then the SS burst is advantageously aligned with the boundary of the time slot having a 60kHz subcarrier spacing. Therefore, if the bitmap indicates whether to use an SS burst, the UE can determine whether to transmit an SSB on a time slot basis for each subcarrier spacing in the 6GHz or higher frequency band.

[0159] The difference from the previous example is that the additional information is indicated in the form of a bitmap. In this case, since the bitmap information should be sent for the 8 SSBs included in each SS burst, 8 bits are required, and the corresponding additional information is generally applied to all SS bursts. For example, if the bitmap information of the SS burst indicates the use of SS burst #0 and SS burst #1, and the additional bitmap information of the SSBs indicates that the first and fifth SSBs in the SSBs are sent, then the first and fifth SSBs of both SS burst #0 and SS burst #1 are sent, so the total number of SSBs actually sent is 4.

[0160] Meanwhile, some neighboring cells may not be included in the cell list. Neighboring cells not included in the cell list use a default format for the actual transmitted SSB. Because of this default format, the UE can measure neighboring cells not included in the list. The default format can be predefined or configured by the network.

[0161] Meanwhile, if the actual SSB information transmitted in the serving cell does not match the actual SSB information transmitted in neighboring cells, the UE can obtain the actual SSB information by giving priority to the actual SSB information transmitted in the serving cell.

[0162] In other words, if the actual SSB information is received in both full bitmap and packet form, the full bitmap information may be more accurate, and therefore the full bitmap information can be used preferentially in SSB reception.

[0163] 4. Signals and channels used for time index indication

[0164] The SSB time index indicator is delivered on the NR-PBCH. If the time index indicator is included as part of the NR-PBCH, such as in the NR-PBCH content, scrambling sequence, CRC, or redundant version, it is securely transmitted to the UE. However, including the time index indicator as part of the NR-PBCH increases the complexity of decoding neighboring cell NR-PBCHs. Furthermore, although it is possible to decode neighboring cell NR-PBCHs, decoding is not mandatory when designing the system. Additionally, which signals and channels are suitable for delivering the SSB time index indicator requires further discussion.

[0165] Because the SSB time index information will be used as reference information for the allocation of time resources for initial access-related channels / signals, such as system information or PRACH preambles in the target cell, the SSB time index information should be securely transmitted to the UE. Meanwhile, for neighboring cell measurement purposes, the time index is used in RSRP measurements at the SSB level. In this case, very accurate SSB time index information may not be necessary.

[0166] In this disclosure, it is proposed to use NR-PBCH DMRS as a signal carrying the SSB time index. Furthermore, it is suggested to include a time index indication in a portion of the NR-PBCH. This portion of the NR-PBCH can be, for example, a scrambled sequence of the NR-PBCH, a redundant version, etc.

[0167] According to this disclosure, the SSB time index can be detected from the NR-PBCH DMRS, and the detected index can be identified by NR-PBCH decoding. Furthermore, for neighboring cell measurement purposes, the index can be obtained from the NR-PBCH DMRS of neighboring cells.

[0168] The time index indicator can be configured in the following two embodiments.

[0169] (Method 1) Single index method, in which each SSB in the SS burst set is indexed.

[0170] (Method 2) Multi-index method, in which indexes are assigned by combining SS burst indexes and SSB indexes.

[0171] If a single-index method such as Method 1 is supported, a large number of bits are required to represent all SSBs within the SS burst set period. In this case, the DMRS sequence and scrambling sequence of the NR-PBCH preferably indicate the SSB indication.

[0172] On the other hand, using a multi-indexing approach, such as Method 2, provides design flexibility for index indication. For example, both the SS burst index and the SSB index can be included in a single channel. Furthermore, each index can be transmitted separately in a different channel / signal. For instance, the SS burst index can be included in the content or scrambling sequence of the NR-PBCH, while the SSB index can be delivered in the DMRS sequence of the NR-PBCH.

[0173] At the same time, the maximum number of SSBs in the configured SS burst varies depending on the carrier frequency range. That is, the maximum number of SSBs is 8 in the frequency range of 6 GHz or lower, and 64 in the frequency range between 6 GHz and 52.6 GHz.

[0174] Therefore, the number of bits required to indicate an SSB, or the number of states required to indicate an SSB, can vary depending on the carrier frequency range. Thus, one of methods 1 and 2 can be considered depending on the carrier frequency range. For example, the single-index method can be applied at 6 GHz or lower frequencies, and the multi-index method can be used at 6 GHz or higher frequencies.

[0175] To describe this in more detail, the SSB time index can be determined by the PBCH DMRS in the frequency range of 6 GHz or lower. In this case, up to 8 states should be identified by the PBCH DMRS sequence. That is, the SSB time index requires 3 bits. Furthermore, the PBCH DMRS sequence can indicate a 5ms boundary (half-time indicator). In this case, a total of 16 states are needed to indicate the DMRS-based SSB time index and the 5ms boundary. In other words, in addition to the 3 bits for the SSB time index, 1 bit is needed to indicate the 5ms boundary. Moreover, in the frequency range of 6 GHz or lower, no bits need to be defined for the SSB time index in the PBCH content.

[0176] Furthermore, if the bits used to indicate the SSB time index are sent in the NR-PBCH DMRS, the decoding performance is better than that of the PBCH content. Additionally, if additional signals are defined to indicate the SSB time index, these additional signals incur signaling overhead. Since the NR-PBCH DMRS is a sequence already defined in the NR system, it does not incur additional signaling overhead, thus preventing excessive signaling overhead.

[0177] Meanwhile, in the 6 GHz or higher frequency range, a portion of the SSB time index can be indicated by the PBCH DMRS, while the remainder can be indicated by the PBCH content. For example, to indicate a total of 64 SSB indices, SSBs can be grouped into 8 SSB groups within an SS burst set, with each SSB group containing up to 8 SSBs. In this case, 3 bits for indicating the SSB group can be defined in the PBCH content, and the SSB time index within the SSB group can be defined via the PBCH DMRS sequence. Furthermore, if a synchronization network can be assumed in the NR system in the 6 GHz or higher frequency range, a PBCH decoding process to obtain the SS burst index from the PBCH content is not required.

[0178] 5. NR-PBCH Content

[0179] In the NR system, the expected payload size of the Master Message Block (MIB) will increase based on the response LS from RAN2. The expected MIB payload size and NR-PBCH content in the NR system are given below.

[0180] 1) Payload: 64 bits (48 bits of information, 16 bits of CRC)

[0181] 2) NR-PBCH content: - At least a portion of SFN / H-SFN - Information regarding the configuration of the public search space - Information regarding the NR carrier center frequency After detecting the cell ID and symbol timing information, the UE can obtain network access information from the PBCH, including SFN, some timing information (such as SSB index and half-frame timing), information related to the common control channel (such as time / frequency location and bandwidth), bandwidth information (such as SSB location), and SS burst set information (such as SS burst set period and actual transmitted SSB index).

[0182] Since the PBCH occupies only 576 REs of limited time / frequency resources, mandatory information must be included in the PBCH. Additionally, if possible, auxiliary signals such as PBCH DMRS can be used to further include mandatory or additional information.

[0183] (1) SFN (System Frame Number)

[0184] In NR, SFNs can be defined to distinguish 10-ms intervals. Furthermore, similar to LTE systems, an index between 0 and 1023 can be introduced as the SFN. The index can be explicitly indicated by bits or implicitly indicated.

[0185] In NR, the PBCH TTI is 80ms and the minimum SS burst time is 5ms. Therefore, up to 16 PBCHs can be transmitted, one every 80ms, and different scrambling sequences can be applied to the encoded PBCH bits for each PBCH transmission. Similar to LTE PBCH decoding, the UE can detect 10ms intervals. In this case, eight SFN states can be implicitly indicated by the PBCH scrambling sequence, and seven bits indicating SFNs can be defined in the PBCH content.

[0186] (2) Timing information within radio frames

[0187] Depending on the carrier frequency range, the SSB index can be explicitly indicated by bits included in the PBCH DMRS sequence and / or the PBCH content. For example, for frequency bands equal to or below 6 GHz, only the 3-bit SSB index is delivered via the PBCH DMRS sequence. Furthermore, for frequency bands of 6 GHz or above, the three LSBs of the SSB index are delivered via the PBCH DMRS sequence, and the three MSBs of the SSB index are delivered via the PBCH content. That is, a maximum of 3 bits for the SSB index can be defined in the PBCH content, only for frequency ranges between 6 GHz and 52.6 GHz.

[0188] Additionally, half-frame boundaries can be indicated by the PBCH DMRS sequence. Specifically, in the 3 GHz or lower frequency band, including half-frame indicators in the PBCH DMRS is more efficient than including them in the PBCH content. That is, FDD is primarily used in the 3 GHz or lower frequency band, so time asynchrony between SFs or time slots can be significant. Therefore, for more accurate time synchronization, half-frame indicators are preferably delivered in the PBCH DMRS, which has better decoding performance than the PBCH content.

[0189] Conversely, in frequency bands above 3 GHz, TDD is primarily used, resulting in less time asynchrony between subframes or time slots. Therefore, delivering half-time indicators in PBCH content may be less important.

[0190] Simultaneously, half-time indicators can be delivered in both PBCH DMRS and PBCH content.

[0191] (3) The number of OFDM symbols included in the time slot

[0192] Regarding the number of OFDM symbols in time slots within the 6 GHz or lower carrier frequency range, 7-OFDM symbol time slots and 14-OFDM symbol time slots are considered in NR. If it is determined that both types of time slots within the 6 GHz or lower carrier frequency range are supported, a time slot type indicator should be defined to indicate the time resources of the control resource set (CORESET).

[0193] (4) Identify missing RMSI information corresponding to PBCH.

[0194] In NR, SSBs can be used for operational measurements and for providing network access information. Specifically, for wideband CC operations, multiple SSBs can be sent for measurements.

[0195] However, it may not be necessary to deliver the RMSI at every frequency location carrying the SSB. That is, for resource efficiency, the RMSI can be transmitted at specific frequency locations. In this case, the UE performing the initial access procedure may be unsure whether an RMSI is provided in the detected frequency location. To address this issue, it may be necessary to define a bit field for identifying the absence of an RMSI corresponding to the PBCH in the detected frequency region. Simultaneously, a method for identifying the absence of an RMSI corresponding to the PBCH without using this bit field should also be considered.

[0196] Therefore, SSBs without RMSI will be transmitted in frequency locations not defined by the frequency grid. In this case, the aforementioned problem can be overcome because the UE performing the initial access procedure cannot detect the SSB.

[0197] (5) SS burst set period and actual SS blocks sent

[0198] For measurement purposes, information regarding the period of SS burst sets and the actual SSBs transmitted can be indicated. Therefore, this information is preferably included in the system information for cell measurements and inter-cell / intra-cell measurements. That is, it is not necessary to define the aforementioned information in the PBCH content.

[0199] (6) Bandwidth-related information

[0200] The UE attempts to detect signals within the SSB bandwidth during the initial synchronization process, which includes cell ID detection and PBCH decoding. Subsequently, the UE can obtain system information within the bandwidth indicated in the PBCH content and continue with the initial access procedure, including the RACH process. The bandwidth can be defined for the purpose of the initial access procedure. Frequency resources for COCRESET, RMSI, OSI, and RACH messages can be defined within the bandwidth of the DL common channel. Additionally, the SSB can be located within a portion of the DL common channel bandwidth. In summary, the bandwidth of the DL common channel can be defined within the PBCH content. Furthermore, an indication of the relative frequency position between the SSB bandwidth and the DL common channel bandwidth can be defined within the PBCH content. To simplify the indication of relative frequency position, multiple bandwidths of the SSB can be considered as candidate locations where the SSB is located within the DL common channel bandwidth.

[0201] (7) Parameter set information

[0202] For SSB transmission, subcarrier spacings of 15, 30, 120, and 240 kHz are used. Simultaneously, subcarrier spacings of 15, 30, 60, and 120 kHz are used for data transmission. The same subcarrier spacing can be used for transmitting SSB, CORESET, and RMSI. Once RAN1 has identified the information regarding the aforementioned subcarrier spacings, it is not necessary to define parameter set information in the PBCH content.

[0203] Simultaneously, possible variations in the subcarrier spacing of CORESET and RMSI can be considered. If only 15 subcarrier spacings are applied to SSB transmission according to the protocol regarding minimum carrier bandwidth in RAN4, the subcarrier spacing may need to be changed to 30kHz for the next process after PBCH decoding. Furthermore, if a 240kHz subcarrier spacing is used for SSB transmission, the subcarrier spacing needs to be changed for data transmission because a 240kHz subcarrier spacing is not defined for data transmission. If RAN1 can change the subcarrier spacing used for data transmission through the PBCH content, a 1-bit indicator can be defined for this purpose. Depending on the carrier frequency range, the 1-bit indicator can be interpreted as {15, 30kHz} or {60, 120kHz}. Additionally, the indicated subcarrier spacing can be considered as the default parameter set of the RB grid.

[0204] (8) Payload size

[0205] Considering PBCH decoding performance, a maximum payload size of 64 bits can be assumed, as shown in [Table 2].

[0206] [Table 2]

[0207] 6. NR-PBCH scrambling

[0208] The type and sequence initialization of the NR-PBCH scrambling sequence will be described. Although the use of the PN sequence in NR can be considered, it is preferable to reuse the Gold sequence as the NR-PBCH scrambling sequence if using the Gold sequence of length 31 defined in the LTE system as the NR-PBCH sequence does not cause serious problems.

[0209] Furthermore, the scrambling sequence can be initialized with at least the cell-ID, and can also be initialized using 3 bits of the SSB index indicated by the PBCH-DMRS. Additionally, if a half-frame indication is indicated by the PBCH-DMRS or another signal, the half-frame indication can also be used as a seed value for initializing the scrambling sequence.

[0210] 7. NR-PBCH DMRS Design

[0211] In NR systems, a DMRS is introduced for the phase reference of the NR-PBCH. Furthermore, NR-PSS / NR-SSS / NR-PBCH exist in each SSB, and the OFDM symbols carrying NR-PSS / NR-SSS / NR-PBCH are continuous within a single SSB. However, if it is assumed that NR-SSS and NR-PBCH are transmitted using different transmission schemes, it cannot be assumed that NR-SSS is used as the RS for NR-PBCH demodulation. Therefore, in NR systems, the NR-PBCH should be designed under the assumption that NR-SSS is not used as the RS for NR-PBCH demodulation.

[0212] To design a DMRS, DMRS overhead, time / frequency location, and scrambling sequence should be considered.

[0213] The overall PBCH decoding performance can be determined by channel estimation performance and NR-PBCH coding rate. Due to the trade-off between channel estimation performance and PBCH coding rate, an appropriate number of REs should be determined for DMRS transmission. For example, better performance can be provided when four REs per RB are allocated to DMRS. When two OFDM symbols are allocated for NR-PBCH transmission, 192 REs are used for DMRS and 384 REs are used for MIB transmission. In this case, assuming a payload size of 64 bits, a coding rate equal to 1 / 12 of the LTE PBCH coding rate can be achieved.

[0214] Furthermore, if multiple OFDM symbols are allocated for NR-PBCH transmission, the question arises as to which OFDM symbol will include the DMRS. To prevent performance degradation caused by residual frequency offset, the DMRS is preferably located in all OFDM symbols carrying the NR-PBCH. Therefore, the DMRS can be included in all OFDM symbols used for NR-PBCH transmission.

[0215] Meanwhile, regarding the location of OFDM symbols carrying NR-PBCH, the PBCH DMRS is used as a time / frequency tracking RS, and frequency tracking is more accurate when the interval between two OFDM symbols carrying the DMRS is larger. Therefore, the first and fourth OFDM symbols can be allocated for NR-PBCH transmission.

[0216] Furthermore, an interleaving mapping in the frequency domain can therefore be assumed for the frequency location of the DMRS that can be shifted according to the cell ID. The advantage of a uniformly distributed DMRS pattern is that DFT-based channel estimation can be used, which provides the best performance in 1-D channel estimation. Additionally, wideband RB bundling can be used to improve channel estimation performance.

[0217] For DMRS sequences, pseudo-random sequences defined according to the type of Gold sequences can be used. The length of the DMRS sequence can be defined by the number of DMRS REs per SSB. Alternatively, DMRS sequences can be generated based on the cell ID and the slot number / OFDM symbol index within the default period of 20ms for the SS burst set. Furthermore, the SSB index can be determined based on the slot and OFDM symbol index.

[0218] Simultaneously, the NR-PBCH DMRS should be scrambled based on the 1008 cell IDs and the 3-bit SSB index. This is because a comparison of detection performance based on the number of hypotheses in the DMRS sequence reveals that 3 bits are best suited to the number of hypotheses in the DMRS sequence. However, since the detection performance loss for 4 to 5 bits appears to be minimal, it is acceptable to use either 4 or 5 bits of hypotheses.

[0219] Meanwhile, since the SSB time index and the 5ms boundary should be represented by the DMRS sequence, the design should be made to have a total of 16 hypotheses.

[0220] In other words, the DMRS sequence should at least represent the cell ID, the SSB index within the SS burst set, and the half-frame boundary (half-frame indicator), and can be initialized by the cell ID, the SSB index within the SS burst set, and the half-frame boundary (half-frame indicator). The specific initialization equation is given as [Equation 1].

[0221] [Equation 1]

[0222] here, This represents the SSB index in the SSB group, and if If HF is the cell ID, then HF represents the half-frame indicator index with values ​​of {0, 1}.

[0223] For NR-PBCH DMRS sequences, a 31-bit Gold sequence can be used, similar to the LTE DMRS sequence. Alternatively, the NR-PBCH DMRS sequence can be generated based on a 7- or 8-bit Gold sequence.

[0224] Meanwhile, since the detection performance is similar when using a Gold sequence of length 31 and a Gold sequence of length 7 or 8, this disclosure proposes to use a Gold sequence of length 31, such as LTE DMRS, and Gold sequences of length greater than 31 can be considered in the frequency range of 6 GHz or higher.

[0225] The DMRS sequence is modulated with QPSK. It can be defined by [Equation 2].

[0226] [Equation 2]

[0227] Furthermore, BPSK and QPSK can be considered modulation schemes for generating DMRS sequences. Although BPSK and QPSK have similar detection performance, QPSK outperforms BPSK in correlation performance. Therefore, QPSK is more suitable as a modulation scheme for generating DMRS sequences.

[0228] Meanwhile, the pseudo-random sequence used to generate the NR-PBCH DMRS sequence is defined as a Gold sequence of length 31, and the length is... The sequence c(n) is defined by the following [Equation 3].

[0229] [Equation 3]

[0230] here, and The first m-sequence has initial values. And the second m sequence has the following characteristics: Defined initial values, where .

[0231] 8. NR-PBCH DMRS graphic design

[0232] Regarding the frequency location of DMRS, two DMRS RE mapping methods can be considered. The fixed RE mapping method fixes the RS mapping area in the frequency domain, while the variable RE mapping method uses V... shift The method shifts the RS position based on the cell ID. The variable RE mapping method advantageously randomizes interference, thus achieving additional performance gains. Therefore, the variable RE mapping method appears to be more preferable.

[0233] The variable RE mapping will be described in detail. The complex modulation symbols included in a half-frame. It can be determined by [Equation 4].

[0234] [Equation 4]

[0235] Here, k and l represent the subcarrier index and OFDM symbol in the SSB, and This represents a DMRS sequence. It can also be derived from... Sure.

[0236] Additionally, RS power boosting can be considered to improve performance. If RS power boosting and V are used together... shift This reduces interference with the total radiated power (TRP). Furthermore, considering the detection performance gain from the RS power boost, the ratio of signal EPRE to PDSCH EPRE is preferably -1.25 dB.

[0237] Simultaneously, the DMRS overhead, time / frequency location, and scrambling sequence should be determined to design the DMRS. The overall PBCH decoding performance can be determined through channel estimation performance and the NR-PBCH coding rate. Due to the trade-off between channel estimation performance and PBCH coding rate, an appropriate number of REs for the DMRS should be determined.

[0238] The tests show that allocating 4 REs (1 / 3 density) per RB to DMRS provides better performance. If two OFDM symbols are used for NR-PBCH transmission, then 192 REs are used for DMRS and 384 REs are used for MIB transmission. In this case, assuming a payload size of 64 bits, the same coding speed as LTE PBCH can be achieved, i.e., 1 / 12 of the coding speed.

[0239] Furthermore, DMRS can be used as a phase reference for NR-PBCH. Two methods for DMRS mapping can be considered here. One method is equidistant mapping, where each PBCH symbol is used and the DMRS sequence is mapped to the subcarriers at equal intervals.

[0240] In the non-equidistant mapping scheme, each PBCH symbol is used, but the DMRS sequence is not mapped within the NR-SSS transmission bandwidth. Instead, NR-SSS is used for PBCH demodulation in the non-equidistant mapping scheme. Therefore, the non-equidistant mapping scheme may require more resources for channel estimation compared to the equidistant mapping scheme. Furthermore, channel estimation based on SSS symbols may be inaccurate due to residual CFO during initial access. In other words, the equidistant mapping scheme is advantageous in terms of CFO estimation and accurate time tracking.

[0241] Furthermore, the equidistant mapping scheme offers additional benefits if SSB time indications are transmitted in the PBCH DMRS. Evaluations of PBCH decoding performance based on actual RE mapping schemes show that the equidistant mapping scheme outperforms the non-equidistant mapping scheme. Therefore, the equidistant mapping scheme is more suitable for the initial access procedure. Moreover, regarding the frequency location of the DMRS, it can be assumed that interleaved DMRS mapping can be performed in the frequency domain based on cell ID shifting. Additionally, the equidistant mapping DMRS pattern can preferably utilize DFT-based channel estimation, which provides optimal performance in 1-D channel estimation.

[0242] 9. Time Index Indication Method

[0243] refer to Figure 15 The timing information includes the SFN, half-frame interval, and SSB time index. For each piece of timing information, the SFN can be represented by 10 bits, the half-frame indicator by 1 bit, and the SSB time index by 6 bits. Here, a portion of the 10 bits of the SFN can be included in the PBCH content. Furthermore, the NR-PBCH DMRS can include 3 bits of the 6 bits of the SSB index.

[0244] Used to indicate, for example Figure 15 An embodiment of the time indexing method shown is given below.

[0245] - Method 1: S2 S1 (PBCH scrambling) + S0 C0 (PBCH content)

[0246] - Method 2: S2 S1 S0 (PBCH scrambling) + C0 (PBCH content)

[0247] - Method 3: S2 S1 (PBCH scrambling) + S0 C0 (PBCH DMRS)

[0248] - Method 4: S2 S1 S0 (PBCH scrambling) + C0 (PBCH DMRS)

[0249] If a half-frame indication is delivered in the NR-PBCH DMRS, the PBCH data can be combined, thereby achieving additional performance improvements. For this purpose, as in methods 3 and 4, a 1-bit half-frame indication can be transmitted in the NR-PBCH DMRS.

[0250] In the comparison between Method 3 and Method 4, although Method 3 can reduce the number of blind decodes, it may result in a loss of PBCH DMRS performance. If PBCH DMRS can deliver 5 bits including S0, C0, B0, B1, and B2 with excellent performance, then Method 3 may be suitable as a timing indication method. However, if PBCH DMRS may not be able to deliver 5 bits with excellent performance, then Method 4 may be suitable as a timing indication method.

[0251] Considering the above, the 7 MSBs of the SFN can be included in the PBCH content, and 2 or 3 LSBs of the SFN can be delivered via PBCH scrambling. Furthermore, the 3 LSBs of the SSB index can be included in the PBCH DMRS, and the 3 MSBs of the SSB index can be included in the PBCH content.

[0252] Alternatively, a method for obtaining the SSB time index of neighboring cells can be considered. Since decoding based on the DMRS sequence is superior to decoding based on the PBCH content, 3 bits of the SSB index can be sent by changing the DMRS sequence within each 5ms time interval.

[0253] Meanwhile, although the SSB time index can be transmitted only in the NR-PBCHDMRS of neighboring cells in the frequency range of 6 GHz or lower, the 64 SSB indices are distinguished by PBCH-DMRS and PBCH content in the frequency range of 6 GHz or higher. Therefore, the UE does not need to decode the PBCH of neighboring cells.

[0254] However, compared to using PBCH-DMRS alone, decoding PBCH-DMRS and PBCH content together may lead to additional complexity in NR-PBCH decoding and reduced PBCH decoding performance. Consequently, it may be difficult to perform PBCH decoding to receive SSBs from neighboring cells.

[0255] In this scenario, the serving cell can be considered to provide configuration related to the SSB index of neighboring cells, rather than decoding the PBCH of neighboring cells. For example, the serving cell provides configuration for 3 MSBs of the SSB index for the target neighboring cell, and the UE detects 3 LSBs from the PBCH-DMRS. The SSB index of the target neighboring cell can then be obtained by combining the 3 MSBs with the 3 LSBs.

[0256] 10. Evaluation of Measurement Results

[0257] The performance measurements based on payload size, transmission scheme, and DMRS will now be described. It is assumed that two OFDM symbols with 24 RBs are used for NR-PBCH transmission. It is also assumed that SS burst sets (i.e., 10, 20, 40, or 80 ms) can have multiple periods, and that coded bits are transmitted within 80 ms.

[0258] (3) DMRS density

[0259] In low SNR regions, improved channel estimation performance is a crucial factor in enhancing demodulation performance. However, while increasing the RS density of the NR-PBCH improves channel estimation performance, it reduces coding speed. Therefore, to balance channel estimation performance and channel coding gain, the decoding performance of different DMRS densities was compared. Figure 16 This is an illustrative view showing the density of DMRS.

[0260] Figure 16 Part (a) shows the use of 2 REs per symbol for DMRS. Figure 16 Part (b) shows the use of 4 REs per symbol for DMRS, and Figure 16 Section (c) shows the use of 6 REs per symbol for DMRS. Additionally, this assessment is based on the assumption of using a single-port-based transmission scheme (i.e., TD-PVS).

[0261] Figure 16 An embodiment of a DMRS pattern for transmission based on a single antenna port is shown. (Reference) Figure 16 When the DMRS are equidistant from each other in the frequency domain, the RS density changes. Furthermore, Figure 17 This is a view showing the performance results for different DMRS densities.

[0262] like Figure 17 As shown, due to its excellent channel estimation performance, Figure 16 The NR-PBCH decoding performance shown in section (b) is superior to Figure 16 The situation shown in part (a). Meanwhile, with... Figure 16 Compared to part (b), Figure 16 The case in part (c) results in a coding speed loss that outweighs the gain in improving channel estimation performance, thus leading to poor performance. For this reason, it seems most appropriate to design a DMRS with an RS density of 4 REs per symbol.

[0263] (4) DMRS time location and CFO estimation

[0264] The detection performance of the SSB index will be described based on the number of DMRS sequence assumptions, modulation type, sequence generation, and DMRS RE mapping. These measurements are based on the assumption that two OFDM symbols out of the 24 RBs are used for NR-PBCH transmission. Furthermore, multiple periods can be considered for the SS burst set, and these periods can be 10ms, 20ms, or 40ms.

[0265] (5) Number of DMRS sequence hypotheses

[0266] Figure 18 Measurement results based on the SSB index are shown. 144 REs and 432 REs were used for DMRS and data in 24 RBs and 2 OFDM symbols, respectively. Long sequences (e.g., Gold sequences of length 31) and QPSK were assumed for the DMRS sequences.

[0267] refer to Figure 18 When measurements are performed, the detection performance of 3 to 5 bits is accumulated twice, showing an error rate of 1% at -6dB. Therefore, in terms of detection performance, 3 to 5 bits of information can be used to represent the number of hypotheses in a DMRS sequence.

[0268] (6) Modulation type

[0269] Figure 19 and 20 Performance measurement results in BPSK and QPSK are shown. In this test, DMRS is assumed to be represented in 3 bits, the DMRS sequence is based on a long sequence, and the power level of the interfering TRP is equal to the power level of the serving TRP.

[0270] refer to Figure 19 and 20 It can be noted that BPSK and QPSK have similar performance. Therefore, using any modulation type to modulate the DMRS sequence will not bring about significant differences in performance measurements. However, refer to... Figure 21 It can be noted that BPSK and QPSK have different related characteristics.

[0271] refer to Figure 21 In regions where the correlation amplitude is equal to or greater than 0.1, BPSK has a wider distribution than QPSK. Therefore, considering multi-cell environments, QPSK is preferred as the modulation type for DMRS. In other words, in terms of correlation characteristics, QPSK is a more suitable modulation type for DMRS sequences.

[0272] (7) Generation of PBCH DMRS sequences

[0273] Figure 22 and 23Measurement results generated from the DMRS sequence are shown. The DMRS sequence can be generated based on a long sequence with a polynomial order of 30 or higher, or a short sequence with a polynomial order of 8 or lower. Furthermore, it is assumed that the DMRS is 3 bits and that the power level of the interfering TRP is equal to the power level of the serving TRP.

[0274] refer to Figure 22 and 23 It can be noted that the detection performance based on short sequence generation is similar to that based on long sequence generation.

[0275] Specifically, although the intention is to increase the correlation performance of the first M-sequence by introducing a polynomial expression of length 7, there is no difference between using a polynomial expression of length 31 for the first M-sequence and the conventional approach. Furthermore, although the sequence is generated by setting the initial value of the first M-sequence to SSBID, it is no different from the conventional approach of fixing the first M-sequence and using the SSBID-cell ID for the second M-sequence.

[0276] Therefore, a Gold sequence of length 31 is used as in LTE, and initialization is performed conventionally by fixing the first M sequence and using the SSBID-cell ID for the second M sequence.

[0277] (8) DMRS RE mapping

[0278] Figure 24 , 25 Figures 26 and 27 show performance measurement results based on the equidistant RE mapping method and the non-equidistant RE mapping method. Here, the DMRS is assumed to be 3 bits, the DMRS sequence is based on a long sequence, and the power level of the interfering TRP is equal to the power level of the serving TRP. Furthermore, only one interference source exists.

[0279] Furthermore, NR-SSS is mapped to 144 REs (i.e., 12 RBs), and NR-PBCH is mapped to 288 REs (i.e., 24 RBs). Meanwhile, in the non-equidistant mapping method, it is assumed that NR-SSS is used for PBCH demodulation, and that PBCH DMRS is not mapped within the NR-SSS transmission bandwidth. Additionally, it is assumed that a residual CFO exists.

[0280] In other words, the above content can be summarized as follows.

[0281] (Iso-distant DMRS mapping) 96 REs per PBCH symbol, that is, a total of 192 REs are used.

[0282] (Non-equidistant DMRS mapping) The DMRS sequence is mapped to subcarriers outside the NR-SSS transmission bandwidth. In this case, NR-SSS is used for PBCH demodulation. Additionally, there are 48 REs per PBCH symbol and 128 REs for NR-SSS symbols, for a total of 224 REs used.

[0283] like Figure 25 As shown, the non-equidistant mapping scheme without CFO includes more REs for channel estimation, thus outperforming the equidistant mapping scheme. However, if a 10% residual CFO exists, the performance of the non-equidistant mapping scheme degrades, while the equidistant mapping scheme exhibits similar performance regardless of CFO. Even though the non-equidistant mapping scheme has more REs for channel estimation, the channel estimation accuracy of NR-SSS symbols is reduced due to the residual CFO. Therefore, it can be noted that the equidistant mapping scheme outperforms the non-equidistant mapping scheme in channel estimation performance when a residual CFO is present.

[0284] like Figure 26 As shown, using a variable RE mapping can achieve the effect of randomizing interference. Therefore, the detection performance of a variable RE mapping is higher than that of a fixed RE mapping.

[0285] Figure 27 The measurement results are shown when RS power boosting is used. Here, it is assumed that the RE transmission power of the DMRS is approximately 1.76 dB higher than the RE transmission power of the PBCH data (= 10). log(1.334 / 0.889)). If variable RE mapping and DMRS power boost are used together, interference from other cells is reduced. For example... Figure 27 As shown, the performance gain with RS power boost is 2 to 3 dB compared to no RS power boost.

[0286] On the other hand, increasing RS power reduces the RE transmission power of PBCH data. Therefore, increasing RS power may affect PBCH performance. Figure 28 and 29 The results of PBCH performance measurements are shown with and without RS power boost. It is assumed that the period of the SS burst set is 40 ms, and the coded bits are transmitted within 80 ms.

[0287] The reduction in RE transmission power for PBCH data may lead to performance loss. However, the resulting increase in RS power improves channel estimation performance, thereby enhancing demodulation performance. Therefore, as... Figure 28 and 29 As shown, the performance is almost identical in both cases. Therefore, the impact of RE transmission power loss for PBCH data can be compensated for by the channel estimation performance gain.

[0288] Table 3 below lists the assumed values ​​for the parameters used in the above performance measurements.

[0289] [Table 3]

[0290] (9) SSB Index Indicator

[0291] Reference Figures 30 to 33 This section describes the evaluation results used to compare the performance of SSB time index indication. For this evaluation, we consider one method of indicating the SSB time index via the PBCH DMRS sequence and another method of indicating the SSB index via the PBCH content. We assume there are a total of 16 states for the SSB time index and the 5ms slot boundary indication, i.e., the indication is represented by 4 bits. In this evaluation, we assume a single SSB of the SS burst set is transmitted, and a time-domain precoder is applied cyclically within the PBCH TTI. Additionally, we assume 192 REs are used for the PBCH DMRS, and the bit size of the MIB, including the CRC, is 64 bits.

[0292] The number of assumptions in this evaluation is 16. This is because 4 bits are needed in the PBCH DMRS to represent the 8 states of the SSB index and the state of the 5ms boundary. Figure 30 and 31 As shown, when accumulated twice, the detection performance of the SSB time index in PBCH DMRS reaches 0.2% at an SNR of -6dB. As observed from this evaluation, PBCH DMRS is more preferably used when indicating the SSB index and the 5ms boundary.

[0293] On the other hand, such as Figure 32 and 33 As shown, even with cumulative decoding performed twice, a 1% PBCH FER cannot be achieved at an SNR of -6dB. Therefore, if the SSB time index is defined only in the PBCH content, the detection performance of the SSB time index may be insufficient.

[0294] The following [Table 4] lists the parameter values ​​assumed for the above evaluation of the SSB index indication.

[0295] [Table 4]

[0296] 11. Bandwidth Component (BWP) for DL ​​common channel transmission

[0297] The initial access procedure for LTE is performed within the system bandwidth configured by the MIB. Furthermore, the PSS / SSS / PBCH are aligned with respect to the system bandwidth. A common search space is defined within the system bandwidth, system information is delivered on the PDSCH within the allocated common search space, and the RACH procedure for Msg 1 / 2 / 3 / 4 is performed.

[0298] Meanwhile, although NR systems support operation within wideband component carriers (CCs), configuring UEs to perform the necessary operations across all wideband CCs is cost-effective. Consequently, achieving a reliable initial access procedure within the system bandwidth may be challenging.

[0299] To avoid this problem, a BWP can be defined for the initial access procedure in NR, such as... Figure 34 As shown. In an NR system, the initial access procedure for SSB transmission, system information delivery, paging, and RACH can be performed within the BWP corresponding to each UE. Furthermore, at least one DL BWP may include a CORESET having a common search space in at least one primary CC.

[0300] Therefore, DL control information related to at least RMSI, OSI, paging, and RACH messages 2 / 4 can be transmitted in the CORESET with a common search space, and DL data channels related to DL control information can be allocated within the DL BWP. Furthermore, the UE can expect to transmit SSB in its corresponding BWP.

[0301] In other words, in NR, at least one DL BWP can be used to transmit the DL common channel. Here, SSB, CORESET with a common search space, and PDSCH for RMSI, OSI, paging, and RACH messages 2 / 4 can be included in the DL common channel. RMSI can be interpreted as System Information Block 1 (SIB 1), which is the system information that the UE should obtain after receiving the MIB on the PBCH.

[0302] (1) Parameter set

[0303] In NR, subcarrier spacings of 15, 30, 60, and 120 kHz are used for data transmission. Therefore, the parameter sets for the PDCCH and PDSCH within the BWP used for the DL common channel can be selected from the parameter set defined for data transmission. For example, one or more of the subcarrier spacings of 15, 30, and 60 kHz can be selected for a frequency range of 6 GHz or below, while one or more of the subcarrier spacings of 60 and 120 kHz can be selected for a frequency range of 6 GHz to 52.6 kHz.

[0304] However, since a 60kHz subcarrier spacing has already been defined for URLLC services in the 6GHz or lower frequency range, it is unsuitable for PBCH transmission in the 6GHz or lower frequency range. Therefore, for DL ​​common channel transmission, 15kHz and 30kHz subcarrier spacings can be used in the 6GHz or lower frequency range, and 60kHz and 120kHz subcarrier spacings can be used in the 6GHz or higher frequency range.

[0305] Simultaneously, NR supports subcarrier spacings of 15, 30, 120, and 240 kHz for SSB transmission. It can be assumed that the same subcarrier spacing is applied to the SSB, the CORESET with a common search space, and the downlink channels for RMSI, paging, and RAR. Therefore, if this assumption is applied, parameter set information does not need to be defined in the PBCH content.

[0306] On the other hand, it may be necessary to change the subcarrier spacing of the DL control channel. For example, if a 240kHz subcarrier spacing is applied to SSB transmissions in the 6GHz or higher frequency band, this 240kHz subcarrier spacing is not used for data transmissions including DL control channel transmissions. Therefore, for data transmissions including DL control channel transmissions, the subcarrier spacing needs to be changed. Thus, if the subcarrier spacing can be changed for data transmissions including DL control channel transmissions, this can be indicated by a 1-bit indicator included in the PBCH content. For example, depending on the carrier frequency range, the 1-bit indicator can be interpreted as indicating {15kHz, 30kHz} or {60kHz, 120kHz}. Furthermore, the indicated subcarrier spacing can be considered as a reference parameter set for the RB grid. The PBCH content can represent the MIB transmitted on the PBCH.

[0307] In other words, in the frequency range of 6 GHz or below, a 1-bit indicator can indicate that the subcarrier spacing for RMSI or OSI, paging, and Msg 2 / 4 used for initial access is 15 kHz or 30 kHz, while in the frequency range of 6 GHz or above, a 1-bit indicator can indicate that the subcarrier spacing for RMSI or OSI, paging, and Msg 2 / 4 used for initial access is 60 kHz or 120 kHz.

[0308] (2) BWP bandwidth used for DLP common channel transmission

[0309] In NR systems, the BWP bandwidth used for the DL common channel does not need to equal the system bandwidth for network operation. In other words, the BWP bandwidth can be narrower than the system bandwidth. That is, while the bandwidth should be wider than the minimum carrier bandwidth, it should not be wider than the minimum UE bandwidth.

[0310] Therefore, a BWP (Bandwidth Limiting Bus) can be defined for DL ​​(Deep Channel) transmission such that the bandwidth of the BWP is wider than the bandwidth of the SSB (Secure Sub-Side Bus), and equal to or less than the specific DL bandwidth of each UE operable in each frequency range. For example, the minimum carrier bandwidth can be defined as 5 MHz, and it can be assumed that the minimum UE bandwidth is 20 MHz in the frequency range of 6 GHz or below. In this case, the bandwidth of the DL common channel can be defined in the range of 5 MHz to 20 MHz. That is, the SSB can be located within a portion of the bandwidth of the DL common channel.

[0311] (3) Bandwidth configuration

[0312] Figure 35 An illustrative bandwidth configuration is shown.

[0313] The UE attempts to detect signals within the SSB bandwidth during the initial synchronization process, which includes cell ID detection and PBCH decoding. Then, the UE can continue the subsequent initial access procedure within the bandwidth of the DL common channel indicated by the network in the PBCH content. In other words, the UE can obtain system information and perform the RACH procedure within the bandwidth of the DL common channel.

[0314] Additionally, an indicator can be defined in the PBCH content to indicate the relative frequency position between the SSB bandwidth and the DL common channel bandwidth. Furthermore, as mentioned above, the PBCH content can represent the MIB transmitted on the PBCH. For example, as... Figure 35 As shown, the relative frequency position between the bandwidth of the DL common channel and the bandwidth of the SSB can be defined by offset information about the interval between the bandwidth of the SSB and the bandwidth of the DL common channel.

[0315] Specifically, refer to Figure 35 The offset value can be indicated in the RB, and the UE can determine that the bandwidth of the DL common channel is located at the offset position corresponding to the indicated number of RBs. Simultaneously, different parameter sets, i.e., different subcarrier spacings, can be configured for the SSB bandwidth and the DL common channel bandwidth. Here, the absolute frequency spacing of the offset indicated in the RB can be calculated for either the subcarrier spacing of the SSB bandwidth or the subcarrier spacing of the DL common channel bandwidth.

[0316] In addition, to simplify the indication of relative frequency positions, the bandwidth of multiple SSBs can be one of the candidate positions of the SSBs within the bandwidth of the DL common channel.

[0317] Furthermore, in NR systems, the bandwidth of the DL common channel does not need to equal the system bandwidth for network operation. In fact, the bandwidth may be narrower than the system bandwidth. That is, while the bandwidth of the DL common channel should be wider than the minimum carrier bandwidth, it should not be wider than the minimum bandwidth of the UE. For example, if it is assumed that the minimum carrier bandwidth is defined as 5MHz in the frequency range of 6GHz or below and the minimum bandwidth of the UE is assumed to be 20MHz, then the bandwidth of the DL common channel can be defined in the range of 5MHz to 20MHz.

[0318] For example, if the bandwidth of the SSB is 5MHz and the bandwidth of the DL common channel is 20MHz, then four candidate locations for detecting the SSB can be defined within the bandwidth of the DL common channel.

[0319] 12. CORESET Configuration

[0320] (1) CORESET information and RMSI scheduling information

[0321] For the network, sending CORESET information, including RMSI scheduling information, to the UE is more efficient than directly indicating RMSI scheduling information. In other words, frequency resource information such as the bandwidth and frequency location of the CORESET can be indicated in the PBCH content. Furthermore, time resource information such as the starting OFDM symbol, duration, and number of OFDM symbols can be configured separately to allow for flexible use of network resources.

[0322] In addition, information about the period, duration, and offset used for monitoring the public search space can be sent from the network to the UE to reduce the detection complexity for the UE.

[0323] Additionally, the transmission type and REG bundle size can be fixed based on the CORESET of the common search space. Here, the transmission type can be classified according to whether the transmitted signals are interleaved.

[0324] (2) The number of OFDM symbols included in the time slot

[0325] Regarding the number of OFDM symbols in a time slot or the carrier frequency range of 6 GHz or below, two candidates are considered: a 7-OFDM symbol time slot and a 14-OFDM symbol time slot. If both types of time slots are determined to support the carrier frequency range of 6 GHz or below in an NR system, a method for indicating the time slot type should be defined to indicate the time resources of the CORESET with a common search space.

[0326] ( 3) Bit size of PBCH content

[0327] Approximately 14 bits can be set to represent the parameter set, bandwidth, and CORESET information in the PBCH content.

[0328] [Table 5]

[0329] (4) Measurement results

[0330] refer to Figure 36 The performance results will be described based on the payload size (i.e., 48, 56, 64, and 72 bits). Here, it is assumed that 384 REs and 192 REs are used for DMRS.

[0331] from Figure 36 It can be noted that if the payload size is as high as 72 bits, the performance requirements for NR-PBCH (i.e., 1% BLER at SNR of -6dB) can be met by using 384 REs for data and 192 REs for DMRS.

[0332] Figure 37 This is a block diagram illustrating the components that implement the transmitting device 10 and receiving device 20 of this disclosure.

[0333] The transmitting device 10 and the receiving device 20 respectively include: radio frequency (RF) units 13 and 23 for transmitting or receiving radio signals carrying information and / or data, signals and messages; memories 12 and 22 for storing various types of information related to communication in a wireless communication system; and processors 11 and 21 operatively coupled to components such as RF units 13 and 23 and memories 12 and 22, and controlling memories 12 and 22 and / or RF units 13 and 23 to perform at least one of the foregoing embodiments of this disclosure.

[0334] Memory 12 and 22 can store programs used to process and control processors 11 and 21, and temporarily store input / output information. Memory 12 and 22 can be used as buffers.

[0335] Processors 11 and 21 typically provide overall control over the operation of various modules in a transmitting or receiving device. Specifically, processors 11 and 21 can perform various control functions to implement this disclosure. Processors 11 and 21 may be referred to as controllers, microcontrollers, microprocessors, microcomputers, etc. Processors 11 and 21 can be implemented by various means, such as hardware, firmware, software, or a combination thereof. In a hardware configuration, processors 11 and 21 may provide application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), etc. In a firmware or software configuration, firmware or software may be configured to include modules, procedures, functions, etc. Firmware or software configured to implement this disclosure may be provided in processors 11 and 21, or may be stored in memories 12 and 22 and executed by processors 11 and 21.

[0336] The processor 11 of the transmitting device 10 performs predetermined encoding and modulation on signals and / or data scheduled by the processor 11 or a scheduler connected to the processor 11, transmits them externally, and then transmits the encoded and modulated signals and / or data to the RF unit 13. For example, the processor 11 converts the transmitted data stream into K layers after demultiplexing, channel coding, scrambling, modulation, etc. The encoded data stream is called a codeword, which is equivalent to a data block provided by the MAC layer, i.e., a transport block (TB). One TB is encoded into one codeword, and each codeword is transmitted to the receiving device in the form of one or more layers. For up-conversion, the RF unit 13 may include an oscillator. The RF unit 13 may include N t N transmitting antennas t It is a positive integer equal to or greater than 1.

[0337] The signal processing of the receiving device 20 is configured to be the opposite of that of the transmitting device 10. The RF unit 23 of the receiving device 20 receives radio signals from the transmitting device 10 under the control of the processor. The RF unit 23 may include N... r The system has one receiving antenna and down-converts the signals received by each antenna to recover the baseband signal. For down-conversion, the RF unit 23 may include an oscillator. The processor 21 can recover the original data that the transmitting device 10 intends to transmit by decoding and demodulating the radio signals received by the receiving antennas.

[0338] Each of RF units 13 and 23 may include one or more antennas. According to embodiments of this disclosure, the antennas transmit signals processed by RF units 13 and 23 to the outside or receive radio signals from the outside, and provide the received radio signals to RF units 13 and 23 under the control of processors 11 and 21. Antennas may also be referred to as antenna ports. Each antenna may correspond to a single physical antenna, or may be configured as a combination of two or more physical antenna elements. Signals transmitted from each antenna may not be further decomposed by receiving device 20. The RS transmitted corresponding to the respective antenna defines the antenna as seen from the side of receiving device 20 and enables receiving device 20 to perform channel estimation for the antenna, whether the channel is a single radio channel from a single physical antenna or a composite channel from multiple physical antenna elements including that antenna. That is, the antenna is defined such that the channel carrying symbols on the antenna can be derived from a channel carrying another symbol on the same antenna. In the case of RF units supporting MIMO in which data is transmitted and received via multiple antennas, the RF unit may be connected to two or more antennas.

[0339] In this disclosure, RF units 13 and 23 can support receiving a BF and transmitting a BF. For example, RF units 13 and 23 can be configured to perform the references in this disclosure. Figures 5 to 8 The exemplary functions described above. Additionally, RF units 13 and 23 can be referred to as transceivers.

[0340] In embodiments of this disclosure, the UE operates as a transmitting device 10 on the UL and as a receiving device 20 on the DL. In embodiments of this disclosure, the gNB operates as a receiving device 20 on the UL and as a transmitting device 10 on the DL. Hereinafter, the processor, RF unit, and memory in the UE are referred to as the UE processor, UE RF unit, and UE memory, respectively, and the processor, RF unit, and memory in the gNB are referred to as the gNB processor, gNB RF unit, and gNB memory, respectively.

[0341] In this disclosure, the gNB processor controls SSB-to-UE transmissions, including PSS / SSS / PBCH. The subcarrier spacing to be applied to the DL common channel is indicated by a 1-bit indicator in the MIB transmitted on the PBCH. This 1-bit indicator specifies a subcarrier spacing of 15 kHz or 30 kHz in the frequency band below 6 GHz, and 60 kHz or 120 kHz in the frequency band above 6 GHz. Furthermore, the subcarrier spacing indicated by the 1-bit indicator is typically applied to RMSI, OSI, and MSg 2 / 4 transmissions.

[0342] In this disclosure, the UE processor controls the reception of SSBs, including PSS / SSS / PBCH, from the gNB. The UE processor receives the subcarrier spacing of the DL common channel via a 1-bit indicator in the MIB of the PBCH. The 1-bit indicator specifies that the subcarrier spacing is 15 kHz or 30 kHz in the frequency band below 6 GHz, and 60 kHz or 120 kHz in the frequency band above 6 GHz. Furthermore, the subcarrier spacing indicated by the 1-bit indicator is typically used for the reception of RMSI, OSI, and MSg 2 / 4.

[0343] The gNB processor or UE processor of this disclosure can be configured to implement this disclosure in a cell operating at a high frequency of 6 GHz or above, wherein an analog BF or a hybrid BF is used.

[0344] As described above, a detailed description of preferred embodiments of the present disclosure has been given to enable those skilled in the art to implement and perform the disclosure. While reference has been made to preferred embodiments of the present disclosure above, those skilled in the art will understand that various modifications and variations can be made to the disclosure within its scope. For example, those skilled in the art can combine the components described in the foregoing embodiments. Therefore, the above embodiments should be interpreted in all respects as illustrative rather than restrictive. The scope of the disclosure should be determined by the appended claims and their legal equivalents, not by the foregoing description, and all variations falling within the meaning and scope of the appended claims are intended to be included therein.

[0345] Industrial applicability

[0346] Although the above-described method and apparatus for transmitting and receiving DL channels have been described in the context of 5G New RAT systems, the method and apparatus are also applicable to various other wireless communication systems besides 5G New RAT systems.

Claims

1. A method performed by a user equipment (UE), the method comprising: Receive the main information block (MIB) in the frequency band; The SCS is determined based on (i) first information related to the subcarrier spacing SCS included in the MIB, and (ii) the frequency band; Based on the first information related to the SCS included in the MIB and the control resource set CORESET information, a downlink control channel is received on the CORESET; as well as The downlink channel is received based on the SCS and the downlink control channel. Wherein, based on the fact that the frequency band is within a first frequency range, the SCS is determined to be either 15kHz or 30kHz based on the first information. Wherein, based on the fact that the frequency band is within the second frequency range, the SCS is determined to be either 60kHz or 120kHz based on the first information. The SCS is used for residual minimum system information, random access response, and paging. The CORESET information includes: (i) second information related to the frequency resources of the CORESET, (ii) third information related to the duration of the CORESET, and (iii) fourth information related to the initial orthogonal frequency division multiplexing (OFDM) symbol of the CORESET.

2. The method according to claim 1, wherein, The MIB is included in the Physical Broadcast Channel (PBCH), and The PBCH is included in the Synchronization Signal / Physical Broadcast Channel (SS / PBCH) block.

3. The method according to claim 1, wherein, The downlink channel is the Physical Downlink Shared Channel (PDSCH) used for the Remaining Minimal System Information, the Random Access Response, or the Paging.

4. The method according to any one of claims 1 to 3, wherein, The CORESET information also includes fifth information for the Common Search Space (CSS) associated with the downlink control channel, and The fifth piece of information includes the monitoring period, monitoring offset, and duration for the CSS.

5. A user equipment (UE), comprising: At least one transceiver; At least one processor; as well as At least one computer memory, operatively connected to the at least one processor and storing instructions, which, when executed, cause the at least one processor to perform operations including: The main information block (MIB) is received in the frequency band via the at least one transceiver; The SCS is determined based on (i) first information related to the subcarrier spacing SCS included in the MIB, and (ii) the frequency band; Based on the first information related to the SCS included in the MIB and the control resource set CORESET information, a downlink control channel is received on the CORESET; as well as The downlink channel is received by the at least one transceiver based on the SCS and the downlink control channel. Wherein, based on the fact that the frequency band is within a first frequency range, the SCS is determined to be either 15kHz or 30kHz based on the first information. Wherein, based on the fact that the frequency band is within the second frequency range, the SCS is determined to be either 60kHz or 120kHz based on the first information. The SCS is used for residual minimum system information, random access response, and paging. The CORESET information includes: (i) second information related to the frequency resources of the CORESET, (ii) third information related to the duration of the CORESET, and (iii) fourth information related to the initial orthogonal frequency division multiplexing (OFDM) symbol of the CORESET.

6. The UE according to claim 5, wherein, The MIB is included in the Physical Broadcast Channel (PBCH), and The PBCH is included in the Synchronization Signal / Physical Broadcast Channel (SS / PBCH) block.

7. The UE according to claim 5, wherein, The downlink channel is the Physical Downlink Shared Channel (PDSCH) used for the Remaining Minimal System Information, the Random Access Response, or the Paging.

8. The UE according to any one of claims 5 to 7, wherein, The CORESET information also includes fifth information for the Common Search Space (CSS) associated with the downlink control channel, and The fifth piece of information includes the monitoring period, monitoring offset, and duration for the CSS.

9. A method performed by a base station (BS), the method comprising: Transmit the main information block (MIB) in the frequency band; Based on the first information related to the subcarrier spacing SCS and the control resource set CORESET information included in the MIB, the downlink control channel is transmitted on the CORESET; as well as The downlink channel is transmitted based on the SCS and the downlink control channel. Specifically, the SCS is determined based on (i) first information related to the SCS included in the MIB, and (ii) the frequency band. Wherein, based on the fact that the frequency band is within a first frequency range, the SCS is determined to be either 15 kHz or 30 kHz based on the first information associated with the SCS. Wherein, based on the fact that the frequency band is within the second frequency range, the SCS is determined to be either 60kHz or 120kHz based on the first information associated with the SCS. The SCS is used for residual minimum system information, random access response, and paging. The CORESET information includes: (i) second information related to the frequency resources of the CORESET, (ii) third information related to the duration of the CORESET, and (iii) fourth information related to the initial orthogonal frequency division multiplexing (OFDM) symbol of the CORESET.

10. A base station (BS), comprising: At least one transceiver; At least one processor; as well as At least one computer memory, operatively connected to the at least one processor and storing instructions, which, when executed, cause the at least one processor to perform operations including: The main information block (MIB) is transmitted in the frequency band via the at least one transceiver; The at least one transceiver transmits a downlink control channel on the CORESET based on the first information related to the subcarrier spacing SCS and the control resource set CORESET information included in the MIB; as well as The downlink channel is transmitted via the at least one transceiver based on the SCS and the downlink control channel. Specifically, the SCS is determined based on (i) first information related to the SCS included in the MIB, and (ii) the frequency band. Wherein, based on the fact that the frequency band is within a first frequency range, the SCS is determined to be either 15 kHz or 30 kHz based on the first information associated with the SCS. Wherein, based on the fact that the frequency band is within the second frequency range, the SCS is determined to be either 60kHz or 120kHz based on the first information associated with the SCS. The SCS is used for residual minimum system information, random access response, and paging. The CORESET information includes: (i) second information related to the frequency resources of the CORESET, (ii) third information related to the duration of the CORESET, and (iii) fourth information related to the initial orthogonal frequency division multiplexing (OFDM) symbol of the CORESET.

11. An apparatus for a user equipment, comprising: At least one processor; as well as At least one computer memory, operatively connected to the at least one processor and storing instructions, which, when executed, cause the at least one processor to perform operations for the user equipment, the operations including: Receive the main information block (MIB) in the frequency band; The SCS is determined based on (i) first information related to the subcarrier spacing SCS included in the MIB, and (ii) the frequency band; Based on the first information related to the SCS included in the MIB and the control resource set CORESET information, a downlink control channel is received on the CORESET; and The downlink channel is received based on the SCS and the downlink control channel. Wherein, based on the fact that the frequency band is within a first frequency range, the SCS is determined to be either 15kHz or 30kHz based on the first information. Wherein, based on the fact that the frequency band is within the second frequency range, the SCS is determined to be either 60kHz or 120kHz based on the first information. The SCS is used for residual minimum system information, random access response, and paging. The CORESET information includes: (i) second information related to the frequency resources of the CORESET, (ii) third information related to the duration of the CORESET, and (iii) fourth information related to the initial orthogonal frequency division multiplexing (OFDM) symbol of the CORESET.

12. A computer-readable storage medium storing at least one computer program, said at least one computer program comprising instructions that, when executed by at least one processor, cause said at least one processor to perform operations, said operations comprising: Receive the main information block (MIB) in the frequency band; The SCS is determined based on (i) first information related to the subcarrier spacing SCS included in the MIB, and (ii) the frequency band; Based on the first information related to the SCS included in the MIB and the control resource set CORESET information, a downlink control channel is received on the CORESET; as well as The downlink channel is received based on the SCS and the downlink control channel. Wherein, based on the fact that the frequency band is within a first frequency range, the SCS is determined to be either 15kHz or 30kHz based on the first information. Wherein, based on the fact that the frequency band is within the second frequency range, the SCS is determined to be either 60kHz or 120kHz based on the first information. The SCS is used for residual minimum system information, random access response, and paging. The CORESET information includes: (i) second information related to the frequency resources of the CORESET, (ii) third information related to the duration of the CORESET, and (iii) fourth information related to the initial orthogonal frequency division multiplexing (OFDM) symbol of the CORESET.

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