Improved SSB structure for wireless communication system

Abstract

This method performed by a base station in a wireless communication system comprises the steps of: generating a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH); and transmitting the SSB, wherein the SSS is composed of one of a plurality of sequences having different lengths, and a first sequence corresponding to a first length from among the plurality of sequences may include a second sequence corresponding to a second length shorter than the first length.

Description

Improved SSB architecture for wireless communication systems

[0001] The present disclosure provides a method for cell detection and link quality measurement in a wireless communication system.

[0002] 5G (5th generation) mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band (above 6GHz) called millimeter wave (mmWave) such as 28GHz and 39GHz. In addition, in the case of 6G (6th generation) mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0005] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access channel (RACH) for NR to simplify random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] Cell search by a terminal is an essential operation for initiating and maintaining mobile communications. If the performance and accuracy of cell search are guaranteed, the terminal can simultaneously search multiple cells and select the most appropriate one to initiate and maintain communications. Conversely, if the performance and accuracy of cell search are not guaranteed, the terminal may experience various issues, such as link loss and handover failure (HOF). The present disclosure provides a synchronization signal structure that takes into account changes in the communication environment that occur as communication systems evolve.

[0009] The present disclosure proposes a structure of a synchronization reference signal for a 6G communication system that is expected to support communication in various frequency ranges and bandwidths and also to support communication through frequency sharing with existing radio access technology (RAT).

[0010] The present disclosure designs an improved SSB (synchronization signal block) structure and provides a method for transmitting and receiving an improved SSB and a device capable of performing the same.

[0011] In one embodiment of the present disclosure, a method performed by a base station in a wireless communication system includes the steps of generating a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS) and a physical broadcast channel (PBCH), and transmitting the SSB, wherein the SSS is composed of one of a plurality of sequences having different lengths, and a first sequence corresponding to a first length among the plurality of sequences may include a second sequence corresponding to a second length shorter than the first length.

[0012] A method performed by a terminal in a wireless communication system according to one embodiment of the present disclosure includes the steps of receiving an SSB including a PSS, an SSS, and a PBCH, and performing cell detection based on the SSB, wherein the SSS is composed of one of a plurality of sequences having different lengths, and a first sequence corresponding to a first length among the plurality of sequences may include a second sequence corresponding to a second length shorter than the first length.

[0013] In a wireless communication system according to one embodiment of the present disclosure, a base station may include at least one transceiver, at least one processor communicatively connected to the at least one transceiver, and a memory communicatively connected to the at least one processor and storing instructions executable by the at least one processor individually or in combination, such that the base station generates an SSB including a PSS, an SSS, and a PBCH, and transmits the SSB. In this case, the SSS may be composed of one of a plurality of sequences having different lengths, and a first sequence corresponding to a first length among the plurality of sequences may include a second sequence corresponding to a second length shorter than the first length.

[0014] In a wireless communication system according to one embodiment of the present disclosure, a terminal may include at least one transceiver, at least one processor communicatively connected to the at least one transceiver, and a memory communicatively connected to the at least one processor and storing instructions that are executable individually or in combination by the at least one processor, such that the terminal receives an SSB including a PSS, an SSS, and a PBCH, and performs cell detection based on the SSB. In this case, the SSS may be composed of one of a plurality of sequences having different lengths, and a first sequence corresponding to a first length among the plurality of sequences may include a second sequence corresponding to a second length that is shorter than the first length.

[0015] According to one embodiment of the present disclosure, cell detection performance can be guaranteed in various communication environments.

[0016] Additionally, according to one embodiment of the present disclosure, an improved SSB structure can be designed.

[0017] Additionally, according to one embodiment of the present disclosure, energy consumption of a base station can be improved with respect to SSB transmission.

[0018] Figure 1 illustrates the SSB structure of a 5G communication system.

[0019] Figure 2 illustrates an example of frequency selective fading of a channel observed when performing transmission beamforming.

[0020] FIG. 3 illustrates an example of a dual sequence synchronization reference signal according to one embodiment of the present disclosure.

[0021] FIG. 4 illustrates an example of a multi-sequence synchronization reference signal according to one embodiment of the present disclosure.

[0022] FIG. 5 illustrates examples of a standard synchronization reference signal and a variable synchronization reference signal according to one embodiment of the present disclosure.

[0023] FIG. 6 illustrates an example of a definition of a synchronization reference signal sequence for each use according to an embodiment of the present disclosure.

[0024] FIG. 7 illustrates an example of sharing synchronization reference signal information according to one embodiment of the present disclosure.

[0025] FIG. 8 illustrates another example of a multi-sequence synchronization reference signal according to an embodiment of the present disclosure.

[0026] FIG. 9 illustrates an example of a method for representing two physical cell identities (PCIDs) with a single transmission of a synchronization reference signal according to one embodiment of the present disclosure.

[0027] FIG. 10 illustrates another example of a method for representing two PCIDs with a single transmission of a synchronization reference signal according to an embodiment of the present disclosure.

[0028] FIG. 11 illustrates an example of a method for simultaneously transmitting 5G SSB and 6G SSB according to one embodiment of the present disclosure.

[0029] FIG. 12 illustrates an example of a method for inter-cell SSB multiplexing and resource sharing according to one embodiment of the present disclosure.

[0030] FIG. 13 illustrates an example of an inter-RAT SSB multiplexing and resource sharing method according to one embodiment of the present disclosure.

[0031] FIG. 14 illustrates signaling between a terminal and a base station according to one embodiment of the present disclosure.

[0032] FIG. 15 is a diagram illustrating the structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0033] FIG. 16 is a diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0034] Communication between a mobile terminal begins when the terminal searches for an appropriate cell and initiates a RACH (Radio Access Control) to that cell. If the RACH operation is successful, a link is established between the serving cell and the terminal, and communication quality is then guaranteed through link management and link adaptation. If the quality of the link between the serving cell and the terminal deteriorates due to a change in the communication environment, such as the terminal's movement, the terminal begins searching for a new cell. If, as a result of the search, a cell that can guarantee better link quality than the current serving cell or source cell is discovered, the terminal sets the cell as the target cell and performs a handover between the source cell and the target cell. In cellular communication, the two operations described above are essential processes for initiating and maintaining communication, and both operations are initiated through the terminal's cell detection operation. If a terminal fails to detect an appropriate cell, initial access may not be possible, or the terminal may connect to a cell that does not guarantee adequate link quality, resulting in degraded communication service quality. Frequent handovers may also result in rapid battery drain. Furthermore, handover failures may result in link disconnection, and handovers to inappropriate cells may also result in a rapid deterioration in communication quality.

[0035] To avoid the above problems, reference signals used for cell detection must ensure sufficient detection coverage (or cell coverage) and high measurement accuracy (or cell detection reliability). Simultaneously, they must be able to maintain the terminal's cell detection complexity at an appropriate level.

[0036] To address the above, current communication systems utilize a dual-synchronization reference signal architecture. UEs simultaneously perform cell detection and downlink (DL) synchronization based on synchronization reference signals defined for each cell. According to this dual-synchronization reference signal architecture, the synchronization reference signal is composed of two time-dependent reference signals, called the Primary Synchronization Signal (PSS) and the Secondary Synchronization Signal (SSS). UEs perform blind detection of the PSS through time domain processing, thereby obtaining information about the timing at which the PSS is received. Since this blind detection requires extremely high detection complexity from the UE, it is common to design the PSS to have a smaller number of cases than the number of cell identities, or Physical Cell Identity (PCIDs), supported by the system. 5G supports more than 1,000 PCIDs. For PSS, it is defined to be generated by selecting one of only three sequences. In other words, PSS can be said to be generated and transmitted according to a sequence defined for each cell group. After receiving the PSS, the terminal obtains information about the downlink (DL) timing of the corresponding cell, or roughly information about the frequency domain synchronization of the corresponding cell. Based on the above information, the terminal performs an FFT (fast Fourier transform) operation on the SSS, and through subsequent operations, secures DL frequency domain synchronization for the corresponding cell.In addition, after performing the FFT operation, the PCID-related information recorded in the SSS and the information on the PCID group that secured PSS communication are collected to secure the cell identity (e.g., PCID) of the corresponding cell. Information on the link quality that each cell can guarantee is also secured by measuring the reception performance of the SSS, for example, the RSRP (reference signal received power) or RSRQ (reference signal received quality) of the SSS.

[0037] Compared to PSS, SSS offers a wider range of scenarios and is cell-specific rather than cell-group specific. Since the UE already acquires DL timing information through PSS reception when receiving SSS, it can perform SSS reception with relatively low detection complexity. This means that SSS can be generated using a wider variety of sequences. Due to these characteristics, SSS can be generated using hundreds of different sequences, and it is possible to configure neighboring cells in each region to transmit SSS using different radio resources. Based on this, link quality information measured through SSS is utilized as cell-specific link quality information representing each cell.

[0038] Figure 1 illustrates the SSB structure of a 5G communication system.

[0039] Referring to Figure 1, PSS and SSS have the same bandwidth and are transmitted through the same band. There is a time offset of 1 symbol between PSS and SSS. The physical broadcast channel (PBCH) is a channel that receives both PSS and SSS and secures DL synchronization, and is transmitted through a wider bandwidth and more radio resources than PSS / SSS to convey sufficient information. Since 5G is expected to support communication through a higher band with more severe path attenuation than LTE, a PSS and SSS structure using a longer sequence than LTE was adopted as an alternative to the path attenuation.

[0040] 6G is expected to enable communications over higher bandwidths and wider bandwidths than 5G, and MIMO techniques, including beamforming, are expected to be actively utilized as an alternative to overcome increased path attenuation. When beamforming is applied, the channel between the transmitter and receiver is typically configured through a small number of paths, which causes the channel to experience slow fading in the frequency domain. Frequency domain slow fading refers to a channel in which the channel gain and phase shift values ​​change relatively slowly with frequency. This means that when dividing the system band into subbands, the average channel gain for each subband may be measured differently. Therefore, when measuring link quality for slow frequency domain fading channels, it is necessary to use a sufficiently wide measurement band.

[0041] Figure 2 illustrates an example of frequency selective fading of a channel observed when performing transmission beamforming.

[0042] Referring to Figure 2, it can be seen that the SSS bandwidth or SSB bandwidth defined in 5G is too narrow to overcome frequency selectivity.

[0043] Increasing the synchronization reference signal or the overall SSB transmission bandwidth is the most reliable approach, but this poses a risk of excessively increasing terminal detection complexity. Furthermore, given the anticipated implementation of terminals with diverse capabilities, increasing SSB bandwidth could have the disadvantage of making it difficult to detect cells with low or reduced capabilities.

[0044] To address the above issues, the present disclosure proposes a synchronization reference signal structure having a dual structure. According to the technique presented in the present disclosure, the synchronization reference signal can be detected using short sequences and long sequences.

[0045] FIG. 3 illustrates an example of a dual sequence synchronization reference signal according to one embodiment of the present disclosure.

[0046] Referring to FIG. 3, the base station can generate a short sequence or a long sequence for each of the PSS and SSS and use them to transmit the PSS and SSS. The short sequence is a sequence for detecting a synchronization reference signal of a low-capability UE and can be defined as a part of a long sequence. The long sequence can be a sequence for detecting a synchronization reference signal of a UE that supports general capability or high capability. The terminal can perform cell detection and synchronization using the short sequence or the long sequence depending on the SSB reception or synchronization reference signal detection capability. That is, a number of different values ​​of sequence length can be defined for the PSS and SSS depending on the capability of the terminal.

[0047] For example, when mapping to frequency-side wireless resources, a short sequence and a long sequence may be mapped so that the center frequency matches (310 in FIG. 3), the lowest frequency matches (320 in FIG. 3), or the highest frequency matches (330 in FIG. 3).

[0048] When various terminal capabilities are defined for SSB reception or synchronization reference signal detection, synchronization reference signal configurations with more diverse detection bandwidths, such as triple or quadruple, are possible.

[0049] FIG. 4 illustrates an example of a multi-sequence synchronization reference signal according to one embodiment of the present disclosure.

[0050] Referring to Fig. 4, the short sequence is a sequence to support cell detection of a terminal with minimum capability and can be defined as a low capability sequence, a reduced capability (REDCAP) sequence, or a least capability sequence. Other sequences are sequences to support more improved cell detection and cell selection and can be defined as a middle / moderated capability sequence, an extended capability sequence, etc. In addition, reflecting this, the short sequence can be defined as a base sequence guaranteed by the system, and other sequences can be defined as a flexible sequence to ensure improved performance.

[0051] For example, a REDCAP sequence, a middle capability sequence, and an extended capability sequence may be mapped to match the center frequency when mapping to a frequency-side wireless resource (410 in FIG. 4), to match the lowest frequency (420 in FIG. 4), or to match the highest frequency (430 in FIG. 4).

[0052] Additionally, a base sequence can be defined as a sequence that supports measurements by all terminals and across all bands. A flexible sequence, on the other hand, can be configured so that its size can be adjusted for each band, each bandwidth, or environment in which communication is performed.

[0053] FIG. 5 illustrates examples of a standard synchronization reference signal and a variable synchronization reference signal according to one embodiment of the present disclosure.

[0054] Referring to FIG. 5, each of the PSS and the SSS can be set to a base sequence or a flexible sequence (510, 520, 530 in FIG. 5). Alternatively, the PSS can be set to a base sequence, and the SSS can be set to a base sequence or a flexible sequence (540, 550, 560 in FIG. 5).

[0055] 510 and 540 of Fig. 5 illustrate PSS and SSS sequences in frequency band A. 520 and 550 of Fig. 5 illustrate PSS and SSS sequences in frequency band B. 530 and 560 of Fig. 5 illustrate PSS and SSS sequences in frequency band C. In each of frequency bands A, B, and C, the base sequence is a commonly applied sequence, and the flexible sequence may be a sequence whose length changes depending on the frequency band.

[0056] FIG. 5 illustrates an example of mapping a base sequence and a flexible sequence to frequency-side wireless resources so that their center frequencies match. However, the scope of the present disclosure is not limited thereto, and the base sequence and the flexible sequence may be mapped to frequency-side wireless resources so that their lowest frequencies match. Alternatively, the base sequence and the flexible sequence may be mapped to frequency-side wireless resources so that their highest frequencies match.

[0057] Alternatively, different sequences can be used depending on the purpose of receiving the synchronization reference signal as well as the capabilities of the terminal. For example, if the terminal performs synchronization reference signal reception for the purpose of initial access, the terminal randomly performs blind detection for DL ​​timing, which causes the terminal to bear very high detection complexity when measuring the synchronization reference signal. To reflect this, the short sequence can be defined as the sequence for initial access, and the long sequence can be defined as the sequence for mobility support. Alternatively, the sequences can be further divided into sequences for initial access, sequences for idle UE mobility, and sequences for RRC connected UE mobility.

[0058] FIG. 6 illustrates an example of a definition of a synchronization reference signal sequence for each use according to an embodiment of the present disclosure.

[0059] Referring to Fig. 6, depending on the purpose of the synchronization reference signal, the sequence can be divided into a sequence for initial access, a sequence for idle UE mobility, and a sequence for RRC connected UE mobility. When mapping to frequency-side radio resources, each sequence can be mapped so that the center frequency matches (610 in Fig. 6), the lowest frequency matches (620 in Fig. 6), or the highest frequency matches (630 in Fig. 6).

[0060] FIG. 7 illustrates an example of a procedure for sharing synchronization reference signal information according to one embodiment of the present disclosure.

[0061] Referring to FIG. 7, in operation 710, the UE may perform initial access by receiving PSS / SSS. In operation 720, the UE may select a cell based on the PSS / SSS and perform a RACH procedure with the selected cell. If the UE succeeds in initial access and switches to RRC connected mode, in operation 730, the serving cell may transmit synchronization reference signal information about neighboring cells, such as neighboring cells, candidate cells, and target cells, to the UE. The information may include rough information about DL timing, such as information about DL synchronization between cells, information about slot offsets, and information about DL timing differences between cells. Upon receiving the information, in operation 740, the UE may perform synchronization reference signal detection or cell detection for a cell with which the information is shared with lower detection complexity, and thus perform synchronization reference signal detection or cell detection / selection based on a wider bandwidth. Based on the synchronization reference signal detection / measurement results based on the above wide bandwidth, the terminal can perform enhanced reporting on the link quality of adjacent cells in operation 750. In operation 760, the serving cell can select a target cell based on the above reporting and perform a handover.

[0062] As described above, depending on the detection / measurement capability of the terminal, information shared in the measurement configuration, etc., the terminal may perform detection / measurement in different ways for the same detection / measurement reference signal or perform detection / measurement through different bandwidths / radio resources, and report the detection / measurement results to the base station. That is, in measuring and reporting the same measurement contents for the same reference signal, multiple different detection / measurement methods and reports therefor may be set or instructed by the base station. When the different or multiple detection / measurement methods are instructed by the base station, the base station may transmit necessary information or additional information to the terminal to support the different or multiple detection / measurements.

[0063] FIG. 8 illustrates another example of a multi-sequence synchronization reference signal according to an embodiment of the present disclosure.

[0064] As previously explained, PSS detection requires higher detection complexity than SSS detection. Considering this, a method of setting PSS to a single sequence length and SSS to multiple sequence lengths may be considered. Referring to Fig. 8, PSS may be set to a single sequence length, and SSS may be set to a short sequence or a long sequence. When PSS and SSS sequences are mapped to frequency-side wireless resources, they may be mapped so that their center frequencies match (810 in Fig. 8), their lowest frequencies match (820 in Fig. 8), or their highest frequencies match (830 in Fig. 8).

[0065] When a single transceiver or base station implements two or more cells, this is called co-located carrier aggregation (CA) or co-located cell. Co-located CA is when two or more cells defined in different bands are implemented by the same network transceiver, and co-located cell includes when two or more cells defined in the same band are implemented by the same network transceiver. For example, when spectrum sharing between RATs is implemented, it is possible to implement a method in which different RATs performing spectrum sharing are implemented with the same RU (radio unit), and each DU (distributed unit) that implements operations according to the standards of each RAT is implemented and connected to the same RU.

[0066] When two or more cells need to be implemented through the same transceiver as in the example above, the synchronization reference signal transmitted by the transceiver must be able to express the identity of each cell, for example, the PCID of each cell. In the case of existing communication systems, when it is necessary to express two or more PCIDs as described above, synchronization signals according to each PCID are transmitted separately. For example, when spectrum sharing between LTE and 5G is implemented, synchronization reference signals according to the PCID of each LTE cell and 5G cell must be transmitted separately. This is a factor that reduces spectral efficiency.

[0067] One embodiment of the present disclosure provides a method for representing two or more cell identities, for example, two or more PCIDs, as a single common synchronization reference signal transmission and transmitting the signal to a terminal. In the above-described embodiment of the present disclosure, a method is presented in which a single synchronization reference signal supports terminal detection through two or more different sequences. As a method for implementing this, a method is presented in which a long sequence is generated based on one identity, for example, a PCID, and a portion of the long sequence is defined as a short sequence. In other words, a method is presented in which two or more sequences are generated based on one sequence generator and one identity value. In the following, a method is presented in which each sequence is generated based on a different identity, for example, a different PCID.

[0068] FIG. 9 illustrates an example of a method for representing two PCIDs with a single transmission of a synchronization reference signal according to one embodiment of the present disclosure.

[0069] Referring to FIG. 9, when a terminal receives a PSS / SSS corresponding to a short sequence, it can recognize that this is a synchronization signal for cell A defined by PCID A, and that the measured link quality is the link quality provided by cell A. Conversely, when a terminal receives a PSS / SSS corresponding to a long sequence, it can recognize that this is a synchronization signal for cell B defined by PCID B, and that the measured link quality is the link quality provided by cell B. 910 of FIG. 9 illustrates an example in which PSS / SSS sequences are mapped to frequency-side radio resources so that their center frequencies match. 920 of FIG. 9 illustrates an example in which PSS / SSS sequences are mapped to frequency-side radio resources so that their lowest frequencies match. 930 of FIG. 9 illustrates an example in which PSS / SSS sequences are mapped to frequency-side radio resources so that their highest frequencies match.

[0070] For another example, as described above, PSS detection requires higher detection complexity than SSS detection. Considering this, PSS can be set to a single sequence length (i.e., a short sequence), and SSS can be set to a short sequence or a long sequence. 940 of FIG. 9 illustrates an example in which PSS / SSS sequences are mapped to frequency-side wireless resources so that their center frequencies match. 950 of FIG. 9 illustrates an example in which PSS / SSS sequences are mapped to frequency-side wireless resources so that their lowest frequencies match. 960 of FIG. 9 illustrates an example in which PSS / SSS sequences are mapped to frequency-side wireless resources so that their highest frequencies match.

[0071] FIG. 10 illustrates another example of a method for representing two PCIDs with a single transmission of a synchronization reference signal according to an embodiment of the present disclosure.

[0072] Referring to FIG. 10, it is possible to express two or more PCIDs using one sequence generator, or to express multiple PCIDs using a combination of two or more independently generated sequences.

[0073] Specifically, referring to 1010 of FIG. 10, when the terminal receives SSS corresponding to sequence #1, it can recognize that this is a synchronization signal for cell A defined as PCID A, and that the measured link quality is the link quality provided by cell A. When the terminal receives SSS corresponding to sequence #2, it can recognize that this is a synchronization signal for cell B defined as PCID B, and that the measured link quality is the link quality provided by cell B.

[0074] Referring to 1020 to 1040 of FIG. 10, when the terminal receives an SSS corresponding to sequence #1, it can recognize that this is a synchronization signal for cell A defined as PCID A, and that the measured link quality is the link quality provided by cell A. When the terminal receives an SSS corresponding to (i) a combination of sequence #1 and sequence #2 or (ii) a combination of sequence #1, sequence #2, and sequence #3, it can recognize that this is a synchronization signal for cell B defined as PCID B, and that the measured link quality is the link quality provided by cell B.

[0075] FIG. 11 illustrates an example of a method for simultaneously transmitting 5G SSB and 6G SSB according to one embodiment of the present disclosure.

[0076] Referring to FIG. 11, 6G PSS / SSS can utilize 5G PSS or 5G SSS as a short sequence part, and 6G PSS / SSS used for 6G cell detection can be configured by adding an extended part.

[0077] 1110 of FIG. 11 illustrates an example in which, in the case of PSS, both 5G PSS and 6G PSS commonly use a short sequence, and in the case of SSS, 5G SSS is configured with a short sequence and 6G SSS is configured by adding an extended part to 5G SSS. 1120 of FIG. 11 illustrates an example in which, in the case of PSS, 5G PSS is configured with a short sequence and 6G PSS is configured by adding an extended part to 5G PSS, and in the case of SSS, 5G SSS is configured with a short sequence and 6G SSS is configured by adding an extended part to 5G SSS.

[0078] FIG. 12 illustrates an example of an inter-cell SSB multiplexing and resource sharing method according to one embodiment of the present disclosure.

[0079] Referring to FIG. 12, the short sequence and long sequence of PSS or SSS are mapped to different PCIDs, and a TDM (time division multiplexing) method may be applied between the PBCHs mapped to each PCID. For example, the short sequence may be mapped to cell A, the long sequence may be mapped to cell B, and the PBCHs for cell A and cell B may be transmitted through different time resources. That is, when transmitting SSBs for multiple cells, different multiplexing methods may be applied depending on the type of cell-specific broadcast signal / channel, such as CDM (code division multiplexing) being applied between PSS / SSS transmissions of each cell and TDM being applied to PBCH transmissions of each cell. In addition, the PSS / SSS and PBCH may have different periods.

[0080] As an example of the above method, cell A and cell B may be 5G cells and 6G cells, respectively.

[0081] FIG. 13 illustrates an example of an inter-RAT SSB multiplexing and resource sharing method according to one embodiment of the present disclosure.

[0082] Referring to Figure 13, the 5G PBCH and 6G PBCH can be transmitted through different time resources. Additionally, the PSS / SSS and PBCH can have different periods.

[0083] The description of FIG. 12 may be referenced for the description of FIG. 13, and any duplicate content will be omitted. FIG. 14 illustrates signaling between a terminal and a base station according to an embodiment of the present disclosure. The signaling of FIG. 14 may be based on the proposed method and / or embodiment of the present disclosure described above.

[0084] Referring to FIG. 14, in operation 1410, the base station may generate an SSB including a PSS, an SSS, and a PBCH. For example, the base station may generate the PSS and the SSS based on at least one of the frequency band or bandwidth in which the SSB will be transmitted, whether the frequency is shared with another RAT, network control information, terminal capabilities, and the purpose of the SSB transmission. In operation 1420, the base station may transmit the SSB. That is, the terminal may receive the SSB. In operation 1430, the terminal may perform cell detection or cell measurement based on the SSB.

[0085] The above SSS may be composed of one of a plurality of sequences having different lengths. The plurality of sequences may include a first sequence corresponding to a first length and a second sequence corresponding to a second length, wherein the second length may be shorter than the first length. In this case, the first sequence may include the second sequence.

[0086] For example, the first sequence and the second sequence may be mapped to resources such that their center frequencies in the frequency domain match, their lowest frequencies match, or their highest frequencies match.

[0087] For example, the base station can check the capability of the terminal to generate SSB, and generate a sequence of PSS and / or a sequence of SSS based on the capability of the terminal. If the sequence of SSS is generated based on the capability of the terminal, the first sequence corresponding to the first length can be for a terminal with normal capability or a terminal with extended capability, and the second sequence corresponding to the second length can be for a terminal with reduced capability. The terminal can detect the PSS and SSS based on the capability of the terminal.

[0088] For example, the first sequence corresponding to the first length may be a sequence whose length changes according to the frequency band, and the second sequence corresponding to the second length may be a sequence that is commonly applied across the entire frequency band.

[0089] For example, the first sequence may correspond to the first PCID and the second sequence may correspond to the second PCID. In this case, the second sequence may be mapped to an overlapping region of resources corresponding to the first sequence and resources corresponding to the second sequence in the frequency domain.

[0090] For example, if the terminal receives the SSB during the initial connection process, the SSS may be configured as a second sequence, and if the terminal receives the SSB during the mobility process, the SSB may be configured as a first sequence.

[0091] The proposed method and / or embodiments of the present disclosure described above can be performed by the terminal of FIG. 15 and the base station of FIG. 16.

[0092] FIG. 15 is a diagram illustrating the structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0093] Referring to FIG. 15, the terminal may include a transceiver (1510), which refers to a terminal receiving unit and a terminal transmitting unit, a memory (1530), and a terminal processing unit (1520, or terminal control unit or processor). Depending on the communication method of the terminal described above, the transceiver (1510), the memory (1530), and the terminal processing unit (1520) of the terminal may operate. However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more or fewer components than the components described above. In addition, the transceiver, the memory, and the processor may be implemented in the form of a single chip.

[0094] A transceiver unit can transmit and receive signals to and from a base station. Here, the signals may include control information and data. To this end, the transceiver unit may be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and down-converts the frequency of a received signal. However, this is only one embodiment of the transceiver unit, and the components of the transceiver unit are not limited to the RF transmitter and RF receiver. In addition, the transceiver unit may receive a signal through a wireless channel and output it to a processor, and transmit a signal output from the processor through the wireless channel.

[0095] Memory can store programs and data necessary for the terminal's operation. Furthermore, memory can store control information or data included in signals transmitted and received by the terminal. Memory can be comprised of a storage medium, such as ROM, RAM, a hard disk, CD-ROM, or DVD, or a combination of such storage media. Furthermore, there can be multiple memories.

[0096] Additionally, the processor can control a series of processes to enable the terminal to operate according to the aforementioned embodiments. For example, the processor can control components of the terminal to receive SSB. There may be multiple processors, and the processors can perform component control operations of the terminal by executing programs stored in memory.

[0097] For example, in a wireless communication system according to an embodiment of the present disclosure, a terminal may include at least one transceiver, at least one processor communicatively connected to the at least one transceiver, and a memory communicatively connected to the at least one processor. The memory may store instructions that are executable individually or in combination by the at least one processor, and cause the terminal to receive an SSB including a PSS, an SSS, and a PBCH, and to perform cell detection based on the SSB. In this case, the SSS may be composed of one of a plurality of sequences having different lengths, and a first sequence corresponding to a first length among the plurality of sequences may include a second sequence corresponding to a second length that is shorter than the first length.

[0098] FIG. 16 is a diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0099] Referring to FIG. 16, the base station may include a transceiver (1610), which refers to a base station receiving unit and a base station transmitting unit, a memory (1630), and a base station processing unit (1620, or base station control unit or processor). According to the communication method of the base station described above, the transceiver (1610), the memory (1630), and the base station processing unit (1620) of the base station may operate. However, the components of the base station are not limited to the examples described above. For example, the base station may include more or fewer components than the components described above. In addition, the transceiver, the memory, and the processor may be implemented in the form of a single chip.

[0100] A transceiver can transmit and receive signals with a terminal. Here, the signals can include control information and data. To this end, the transceiver can be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts a received signal. However, this is only one embodiment of the transceiver, and the components of the transceiver are not limited to the RF transmitter and RF receiver. In addition, the transceiver can receive a signal through a wireless channel, output it to a processor, and transmit the signal output from the processor through the wireless channel.

[0101] The memory can store programs and data necessary for the operation of the base station. Furthermore, the memory can store control information or data included in signals transmitted and received by the base station. The memory can be comprised of a storage medium, such as ROM, RAM, a hard disk, CD-ROM, or DVD, or a combination of such storage media. Furthermore, there can be multiple memories.

[0102] The processor can control a series of processes to enable the base station to operate according to the embodiments of the present disclosure described above. For example, the processor can determine the structure and / or sequence of the SSB and control each component of the base station to transmit the SSB to the terminal. There may be multiple processors, and the processors can perform component control operations of the base station by executing programs stored in memory.

[0103] For example, in a wireless communication system according to one embodiment of the present disclosure, a base station may include at least one transceiver, at least one processor communicatively connected to the at least one transceiver, and a memory communicatively connected to the at least one processor. The memory may store instructions that are executable individually or in combination by the at least one processor, causing the base station to generate an SSB including a PSS, an SSS, and a PBCH, and to transmit the SSB. In this case, the SSS may be composed of one of a plurality of sequences having different lengths, and a first sequence corresponding to a first length among the plurality of sequences may include a second sequence corresponding to a second length that is shorter than the first length.

[0104] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0105] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0106] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0107] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device performing an embodiment of the present disclosure.

[0108] In the specific embodiments of the present disclosure described above, components included in the invention are expressed in the singular or plural form, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in the plural form may be composed of singular elements, or components expressed in the singular form may be composed of plural elements.

[0109] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are only specific examples to easily explain the technical contents of the present disclosure and help understand the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those skilled in the art that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, the above-mentioned embodiments can be combined and operated with each other as needed. For example, parts of one embodiment of the present disclosure and parts of another embodiment can be combined with each other to operate a base station and a terminal. For example, parts of the first embodiment and the second embodiment of the present disclosure can be combined with each other to operate a base station and a terminal. In addition, although the above-mentioned embodiments have been presented based on an FDD LTE system, other modifications based on the technical idea of ​​the above-mentioned embodiments can be implemented with other systems such as a TDD LTE system, 5G, or NR system.

[0110] Meanwhile, the order of description in the drawings explaining the method of the present invention does not necessarily correspond to the order of execution, and the order of precedence may be changed or executed in parallel.

[0111] Alternatively, the drawings illustrating the method of the present invention may omit some components and include only some components within a scope that does not harm the essence of the present invention.

[0112] In addition, the method of the present invention may be implemented by combining some or all of the contents included in each embodiment within a scope that does not harm the essence of the invention.

[0113] Various embodiments of the present disclosure have been described above. The foregoing description of the present disclosure is for illustrative purposes only, and the embodiments of the present disclosure are not limited to the disclosed embodiments. Those skilled in the art will appreciate that the present disclosure can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present disclosure. The scope of the present disclosure is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present disclosure.

Claims

1. A method performed by a base station in a wireless communication system, A step of generating a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH); and comprising a step of transmitting the above SSB, The above SSS is composed of one of a plurality of sequences having different lengths, and A method, wherein a first sequence corresponding to a first length among the plurality of sequences includes a second sequence corresponding to a second length shorter than the first length.

2. In paragraph 1, A method characterized in that the first sequence corresponding to the first length and the second sequence corresponding to the second length are mapped to resources so that their center frequencies in the frequency domain match, or their lowest frequencies match, or their highest frequencies match.

3. In the first paragraph, the step of generating the SSB comprises: A step for verifying the capability of the terminal; and A method characterized by comprising a step of generating a sequence of the SSS based on the capability of the terminal.

4. In paragraph 3, The first sequence corresponding to the first length is for a terminal of normal capability or a terminal of extended capability, and A method characterized in that the second sequence corresponding to the second length is for a terminal of reduced capacity.

5. In paragraph 1, The first sequence corresponding to the first length is a sequence whose length changes according to the frequency band, and A method characterized in that the second sequence corresponding to the second length is a sequence commonly applied across the entire frequency band.

6. In paragraph 1, The first sequence corresponding to the first length corresponds to the first PCID (physical cell identity), The second sequence corresponding to the second length corresponds to the second PCID, and A method characterized in that the second sequence is mapped to an overlapping region of resources corresponding to the first sequence and resources corresponding to the second sequence in the frequency domain.

7. In a method performed by a terminal in a wireless communication system, A step of receiving a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH); and A step of performing cell detection based on the above SSB is included, The above SSS is composed of one of a plurality of sequences having different lengths, A method, wherein a first sequence corresponding to a first length among the plurality of sequences includes a second sequence corresponding to a second length shorter than the first length.

8. In paragraph 7, When the terminal receives the SSB during the initial connection process, the SSS is composed of a second sequence, A method characterized in that when the terminal receives the SSB during a mobility process, the SSS is composed of a first sequence.

9. In paragraph 7, A method characterized in that the first sequence corresponding to the first length and the second sequence corresponding to the second length are mapped to resources so that their center frequencies in the frequency domain match, or their lowest frequencies match, or their highest frequencies match.

10. In paragraph 7, The sequence of the above SSS is based on the capabilities of the terminal, The first sequence corresponding to the first length is for a terminal of normal capability or a terminal of extended capability, and A method characterized in that the second sequence corresponding to the second length is for a terminal of reduced capacity.

11. In paragraph 7, The first sequence corresponding to the first length is a sequence whose length changes according to the frequency band, and A method characterized in that the second sequence corresponding to the second length is a sequence commonly applied across the entire frequency band.

12. In paragraph 7, The first sequence corresponding to the first length corresponds to the first PCID (physical cell identity), The second sequence corresponding to the second length corresponds to the second PCID, and A method characterized in that the second sequence is mapped to an overlapping region of resources corresponding to the first sequence and resources corresponding to the second sequence in the frequency domain.

13. In a wireless communication system, at a base station, At least one transceiver; At least one processor communicatively connected to said at least one transceiver; and Communicably connected to at least one processor, and executable individually or in combination by said at least one processor, such that said base station: Generate a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH), and A memory for storing a command to transmit the above SSB is included, The above SSS is composed of one of a plurality of sequences having different lengths, and A base station, wherein a first sequence corresponding to a first length among the plurality of sequences includes a second sequence corresponding to a second length shorter than the first length.

14. In the 13th paragraph, the memory: The base station includes a command to check the capability of the terminal and generate the sequence of the SSS based on the capability of the terminal. The first sequence corresponding to the first length is for a terminal of normal capability or a terminal of extended capability, and A base station, characterized in that the second sequence corresponding to the second length is for a terminal with reduced capacity.

15. In a wireless communication system, at a terminal, At least one transceiver; At least one processor communicatively connected to said at least one transceiver; and Communicably connected to at least one processor, and executable individually or in combination by at least one processor, such that the terminal: Receive a synchronization signal block (SSB) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH), and A memory storing a command to perform cell detection based on the above SSB, The above SSS is composed of one of a plurality of sequences having different lengths, A terminal, wherein a first sequence corresponding to a first length among the plurality of sequences includes a second sequence corresponding to a second length shorter than the first length.

Images