Synchronization Signal Block Type Indication for a Device with Reducing Capability

Abstract

Methods, apparatuses, and systems for indicating a synchronization signal block (SSB) type for a user equipment having reduced capabilities are disclosed. In one exemplary aspect, a method for wireless communication includes transmitting, by a base station, system information to a terminal device. The system information indicates whether a cell-defined synchronization signal block (SSB) or a non-cell-defined synchronization signal block (SSB) is applicable for enabling a terminal device with reduced capabilities to perform measurements.

Description

Technical Field

[0001] This patent document generally relates to wireless communication.

Background Art

[0002] Mobile communication technology is making the world more connected and networked. The rapid growth and technological progress of mobile communication have led to further demands for capacity and connectivity. Other aspects such as energy consumption, device cost, spectral efficiency, and latency are also important to meet the requirements of various communication scenarios. Various techniques, including new methods for providing higher quality of service, longer battery life, and improved performance, are being discussed.

Summary of the Invention

Means for Solving the Problems

[0003] This patent document particularly describes techniques related to the indication of synchronization signal block (SSB) types for user equipment with reduced capabilities as disclosed.

[0004] In one exemplary aspect, a method for wireless communication includes transmitting, by a base station, system information to a terminal device. The system information indicates whether a cell-defined synchronization signal block (SSB) or a non-cell-defined SSB is applicable for a terminal device with reduced capabilities to perform measurements.

[0005] In another exemplary aspect, a method for wireless communication includes receiving, by a terminal device with reduced capabilities, from a base station, system information indicating whether a cell-defined synchronization signal block (SSB) or a non-cell-defined SSB is applicable, and performing measurements using the cell-defined SSB or the non-cell-defined SSB based on the system information.

[0006] In another exemplary aspect, a method for wireless communication includes receiving, by a base station, information indicating the reduction capability of a terminal device in a random access procedure.

[0007] In another exemplary aspect, a method for wireless communication includes transmitting, by a terminal device, to a base station, information indicating the reduction capability of the terminal device in a random access procedure.

[0008] In another exemplary aspect, a method for wireless communication includes transmitting, from a first node, configuration information about a non-cell-defined synchronization signal block (SSB) to a neighboring node.

[0009] In another exemplary aspect, a communication device is disclosed. The device includes a processor configured to implement the methods described above.

[0010] In yet another exemplary aspect, a computer program storage medium is disclosed. The computer program storage medium includes stored code. The code, when executed by a processor, causes the processor to implement the methods described.

[0011] These and other aspects are described in this document.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0020] The section headings are used in this document only to improve readability and do not limit the scope of the disclosed embodiments and techniques within each section to that section only. Further, some embodiments are described with reference to the 3rd Generation Partnership Project (3GPP (registered trademark)) New Radio (NR) standard (the "5G") for ease of understanding, and the techniques described can be implemented in different wireless systems implementing protocols other than the 5G protocol.

[0021] In wireless communication, a synchronization signal block (SSB) refers to a synchronization / physical broadcast channel (PBCH) block, and the synchronization / physical broadcast channel (PBCH) block includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH demodulation reference signal (DMRS), and PBCH data. FIG. 1 illustrates an exemplary time-frequency structure of an SSB. The possible time locations of the SSB within a half-frame are determined by the subcarrier spacing, and the periodicity of the half-frame in which the SSB is transmitted is configured by the network. During a half-frame, different SSBs can be transmitted in different spatial directions (e.g., using different beams covering the communication effective range area of the cell). Within the frequency span of a carrier, multiple SSBs can be transmitted. When an SSB is associated with the remaining minimum system information (RMSI), the SSB is referred to as a cell-defined SSB (CD-SSB). The CD-SSB of a primary cell (PCell) is always on the synchronization raster. For cell reselection based on in-band measurements, the UE performs measurements based on the CD-SSB located on the synchronization raster. Early measurements are also based on the CD-SSB.

[0022] There is research to identify features for reducing UE complexity and enabling UEs with reduced capabilities to function efficiently within a communication network. A UE with reduced capabilities is also referred to as a RedCap UE. When an active bandwidth part (BWP) does not include a CD-SSB, a non-cell-defined SSB (NCD-SSB) for a RedCap UE in a connected state (e.g., a radio resource control (RRC) connected state) is introduced to enable activities such as radio link monitoring (RLM), bidirectional automatic repeat request detection (BFD), and / or serving cell measurements by a RedCE.

[0023] Regarding whether an NCD-SSB is used for a RedCap UE in a non-active state (e.g., an RRC idle state or an RRC non-active state), a separate initial BWP has been proposed and two schemes are being discussed.

[0024] Scheme 1: The idle / non-active RedCap UE camps on the cell associated with the CD-SSB and receives paging and system information from the initial DL BWP. Upon access, the RedCap UE switches to a separate RedCap-specific initial BWP. This scheme has little impact on the current cell selection / reselection procedure. Specifically, intra-frequency cell reselection remains based on the frequency of the CD-SSB on which the UE camps.

[0025] Scheme 2: The idle / non-active RedCap UE camps on the cell associated with the NCD-SSB, receives paging, and performs access using a separate RedCap-specific initial BWP. System information is obtained from the initial DL BWP associated with the CD-SSB, for example, upon receipt of a system information modification notification.

[0026] When the NCD-SSB is configured for the RedCap UE in the non-active state using Scheme 2, the NCD-SSB can be used by the RedCap UE for intra-frequency / inter-frequency measurements. However, the RedCap UE lacks instructions for different types of SSBs (e.g., CD-SSB, NCD-SSB) to properly receive the system information block (SIB) and function in other procedures. This patent document discloses techniques that can be implemented in various embodiments to enable the UE, particularly the RedCap UE, to perform intra-frequency and / or inter-frequency measurements based on the NCD-SSB and indicate the use of the NCD-SSB in the RACH procedure. These techniques can also be used by neighboring cells to communicate information about the use of the NCD-SSB.

[0027] Figure 2A is a flowchart representation of a method for wireless communication according to one or more embodiments of the present technology. Method 200 includes, at operation 210, transmitting, by a base station, system information to a terminal device. The system information indicates whether a cell-defined synchronization signal block (SSB) or a non-cell-defined SSB is applicable for a terminal device with reduced capabilities to perform measurements.

[0028] Figure 2B is a flowchart representation of a method for wireless communication according to one or more embodiments of the present technology. Method 250 includes, at operation 260, receiving, by a terminal device with reduced capabilities, from a base station, system information indicating whether a cell-defined synchronization signal block (SSB) or a non-cell-defined SSB is applicable. Method 250 also includes, at operation 270, performing measurements using a cell-defined SSB or a non-cell-defined SSB based on the system information.

[0029] In some embodiments, the system information is carried in a system information block (SIB) for intra-frequency measurements. In some embodiments, the system information is carried in an SIB for inter-frequency measurements. In some embodiments, in response to a non-cell-defined SSB being applicable, the non-cell-defined SSB is associated with cell group resources.

[0030] Figure 3A is a flowchart representation of a method for wireless communication according to one or more embodiments of the present technology. Method 300 includes, at operation 310, receiving, by a base station, information indicating the reduced capabilities of a terminal device in a random access procedure.

[0031] Figure 3B is a flowchart representation of a method for wireless communication according to one or more embodiments of the present technology. Method 350 includes, at operation 360, transmitting, by a terminal device, to a base station, information indicating the reduced capabilities of the terminal device in a random access procedure.

[0032] In some embodiments, the use of dedicated resources for Msg1 of the random access procedure indicates the reduced capabilities of the terminal device. In some embodiments, the information indicating the reduced capabilities is defined in a feature combination information element.

[0033] In some embodiments, the information indicating the reduced capabilities is carried in Msg3 of the random access procedure. For example, the information indicating the reduced capabilities can be carried in the logical channel identifier value of Msg3.

[0034] Figure 4 is a flowchart representation of a method for wireless communication according to one or more embodiments of the present technology. Method 400 includes, at operation 410, transmitting, from a first node, configuration information about a non-cell-defined synchronization signal block (SSB) to neighboring nodes.

[0035] In some embodiments, the configuration information includes at least one of a carrier frequency for a non-cell-defined SSB or an SSB type. In some embodiments, the configuration information is carried in at least one of an access node configuration update confirmation response message, an Xn setup response message, or an Xn setup request message.

[0036] Some examples of the disclosed techniques are further described below.

[0037] (Embodiment 1)

[0038] When NCD-SSB is configured for RedCap UEs in the inactive state using Scheme 2, both CD-SSB and NCD-SSB can be configured within neighboring cells for cell selection. Neighboring cell measurements can thus be performed based on CD-SSB and / or NCD-SSB. An appropriate indication of the SSB type (e.g., CD-SSB or NCD-SSB) is required to enable the RedCap UE to perform neighboring cell measurements as appropriate. Further, when a cell is selected based on measurement results and / or cell reselection rules, if NCD-SSB is used for measurement, the UE needs to switch to the CD-SSB ARFCN and receive the SIB appropriately. Thus, the type of SSB (e.g., CD-SSB or NCD-SSB) needs to be indicated to the UE together with the CD-SSB ARFCN.

[0039] Currently, the UE performs intra-frequency measurements based on CD-SSB located on the synchronization raster for cell reselection. When NCD-SSB is introduced for RedCap UEs in the RRC_IDLE / RRC_INACTIVE state, the NCD-SSB in a separate initial DL BWP can be used for intra-frequency measurements. In some embodiments, the NCD-SSB is configured in some neighboring cells such that either the NCD-SSB or the CD-SSB can be used for cell reselection measurements.

[0040] In an NR communication system, the System Information Block 3 (SIB3) provides neighboring cell information (including cells with specific reselection parameters and blacklisted cell information) relevant for intra-frequency cell reselection. Thus, the SSB type relevant for intra-frequency measurements can be included in SIB3. Table 1 shows exemplary configuration information that can be included in SIB3. Table 1

Table 1

[0041] The UE also performs inter-frequency measurements based on CD-SSBs located on the synchronization raster for cell reselection. In an NR communication system, System Information Block 4 (SIB4) provides information related to inter-frequency cell reselection (including information about other NR frequencies and inter-frequency neighboring cells related to cell reselection). It also includes cell reselection parameters that are common for frequency- and cell-specific reselection parameters. Therefore, the SSB type related to inter-frequency measurements can be included in SIB4. Table 2 shows exemplary configuration information that can be included in SIB4. Table 2

Table 2

[0042] (Embodiment 2)

[0043] When CD-SSBs are used for intra-frequency measurements, inter-frequency measurements, and / or early measurements, neighboring cell information can be exchanged via inter-node messages. For example, CD-SSBs can be carried in a MeasurementTimingConfiguration message, which is used to convey auxiliary information regarding measurement timing.

[0044] When NCD-SSBs are configured for intra-frequency measurements, inter-frequency measurements, and / or early measurements, NCD-SSB related information also needs to be exchanged within the current serving cell and / or the camped cell. The NCD-SSB related information includes at least one of NCD-SSB ARFCN, period, and / or time offset. Table 3 shows an example of NCD-SSB information that can be carried in an inter-node message (e.g., a MeasurementTimingConfiguration message). Table 3

Table 3

[0045] NCD-SSB related information can be carried in the inter-node messages exchanged between neighboring nodes. In particular, the Xn interface supports the exchange of signaling information between two radio access nodes (RAN). For example, NCB-SBB related information can be carried in the RAN node configuration update confirmation response message, Xn configuration response message, Xn configuration request message, and other existing or new messages on the Xn interface (e.g., via MeasurementTimingConfiguration).

[0046] (Embodiment 3)

[0047] Regarding the small data transmission (SDT) procedure based on the configured grant (CG) currently, the CD-SSB is the SSB associated with the CG resource. When the NCD-SSB is configured in a separate initial DL BWP corresponding to the initial UL BWP configured with the CG resource according to Scheme 2 discussed above, an appropriate indication is required to indicate that the NCD-SSB is the SSB associated with the CG resource.

[0048] In some embodiments, small data can be transmitted via the CG resource in the RRC inactive state when certain conditions are met (e.g., exceeding the SSB measurement threshold). Currently, only the CD-SSB can be the SSB associated with the CG resource. When the NCD-SSB is configured in a separate initial DL BWP corresponding to the initial BWP configured for the CG resource, the NCD-SSB becomes the SSB associated with the CG resource.

[0049] (Embodiment 4)

[0050] In the random access (RACH) procedure, the NCD-SSB can be configured in a separate initial DL BWP corresponding to the initial UL BWP composed of RACH common resources. An appropriate indication is required to indicate that the NCD-SSB is the SSB associated with the RACH opportunity.

[0051] To minimize the impact on existing UEs (e.g., non-RedCap UEs and / or legacy UEs with reduced capabilities), early identification of RedCap UEs is required in the RACH procedure (e.g., when the physical downlink shared channel (PDSCH) decoding time N1 and / or the physical uplink shared channel (PUSCH) preparation time N2 are relaxed). Further, for RedCap UEs, a single UE type can be used in identification / indication to further reduce complexity. In some embodiments, early identification of a new generation of RedCap UEs can be included in RACH procedure messaging such as Msg1 and / or Msg3. Some examples of Msg1 and / or Msg3 with RedCap UE identification are described below.

[0052] (Example 1:) Msg1-based early identification of RedCap UEs. In this example, the use of early RedCap UE identification in Msg1 (e.g., in a 4-step RACH procedure) or MSGA (e.g., in a 2-step RACH procedure) can be implicitly indicated by the presence of a dedicated RACH configuration or the use of dedicated RACH resources. For example, a dedicated RACH configuration associated with a RedCap UE present within Msg1 indicates that the RACH resources are used by the RedCap UE. That is, the RedCap UE selects dedicated RACH resources and transmits a preamble to enable the base station to know that it is a RedCap UE. In some embodiments, there is an indication indicating whether the RACH resources can be used by the RedCap UE.

[0053] In some embodiments, the reserved / preliminary bits within the UE capability feature combination information element (IE) can be used to provide an indication of a RedCap UE. Table 4 shows an example of a RedCap UE indication in the FeatureCombination IE. Table 4 [Table 4]

[0054] (Example 2:) Msg3-based early identification of a RedCap UE. In this example, the use of early RedCap UE identification can be included in Msg3 of the RACH procedure. For example, as shown in Table 5, when Msg3 contains common control channel (CCCH) data, the dedicated logical channel identifier (LCID) can include a value that identifies the RedCap UE. Table 5 [Table 5]

[0055] FIG. 5 shows an example of a wireless communication system 500 to which techniques according to one or more embodiments of the present technology may be applied. The wireless communication system 500 can include one or more base stations (BSs) 505a, 505b, one or more wireless devices (or UEs) 510a, 510b, 510c, 510d, and a core network 525. The base stations 505a, 505b can provide wireless services to user devices 510a, 510b, 510c, and 510d within one or more wireless sectors. In some implementations, the base stations 505a, 505b include directional antennas for generating two or more directional beams for providing a wireless communication coverage area within different sectors. The core network 525 can communicate with one or more base stations 505a, 505b. The core network 525 provides connectivity with other wireless communication systems and wired communication systems. The core network can include one or more service subscription databases for storing information related to subscribed user devices or terminal devices 510a, 510b, 510c, and 510d. The first base station 505a can provide wireless services based on a first radio access technology, while the second base station 505b can provide wireless services based on a second radio access technology. The base stations 505a and 505b can be located at the same location on-site or installed separately according to a deployment scenario. The user devices 510a, 510b, 510c, and 510d can support a plurality of different radio access technologies. The techniques and embodiments described herein can be implemented by base stations of the wireless devices described herein.

[0056] FIG. 6 is a block diagram representation of a portion of a radio station to which techniques according to one or more embodiments of the present technology may be applied. A radio station 605, such as a network node, a base station, or a wireless device (or user device, i.e., UE), can include a processor electronic device 610, such as a microprocessor, that implements one or more of the wireless techniques presented in this document. The radio station 605 can include a transceiver electronic device 615 for transmitting and / or receiving wireless signals via one or more communication interfaces, such as an antenna 620. The radio station 605 can include other communication interfaces for transmitting and receiving data. The radio station 605 can include one or more memories (not explicitly shown) configured to store information such as data and / or instructions. In some implementations, the processor electronic device 610 can include at least a portion of the transceiver electronic device 615. In some embodiments, at least some of the disclosed techniques, modules, or functions are implemented using the radio station 605. In some embodiments, the radio station 605 can be configured to implement the methods described herein.

[0057] The other embodiments, modules, and functional operations disclosed, as described in this specification, can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. The other embodiments disclosed can be implemented as one or more computer program products, i.e., as one or more modules of computer program instructions encoded on a computer-readable medium for execution by, or to control the operation of, a data processing apparatus. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition that generates a machine-readable propagated signal, or a combination of one or more of them. The term “data processing apparatus” includes, by way of example, all apparatus, devices, and machines for processing data, including programmable processors, computers, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal generated to encode information for transmission to a suitable receiver device.

[0058] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiler-based or interpreter-based languages, and can be deployed in any form, including as a stand-alone program or as modules, components, subroutines, or other units suitable for use in a computer environment. A computer program does not necessarily correspond to a file in a file system. The program can be stored within a part of a file that holds other programs or data (such as one or more scripts stored within a markup language document), within a single file dedicated to the program, or within multiple cooperating files (such as files that store one or more modules, subprograms, or portions of code). The computer program can be deployed so as to be executed on one computer or on a single location, or distributed across multiple computers located in one or more locations and interconnected by a communication network.

[0059] The processes and logical flows described in this book can be implemented by one or more programmable processors executing one or more computer programs on one or more computer programs to perform functions by acting on input data and generating output. The processes and logical flows can also be implemented by dedicated logic circuitry, such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the apparatus can also be implemented as such. Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random access memory, or both. Essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will be operatively coupled to one or more mass storage devices, such as magnetic, magneto-optical disks, or optical disks, for storing data, or receiving data therefrom, or transferring data thereto, or both. However, a computer need not have such devices. Computer readable media suitable for storing computer program instructions and data include, by way of example, all forms of non-volatile memory, media, and memory devices, including semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices, magnetic disks, such as internal hard disks or removable disks, magneto-optical disks, and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, dedicated logic circuitry.

[0060] This patent document contains many details, which should be construed not as limitations on the scope of any invention or what may be claimed, but rather as descriptions of features that may be particular to specific embodiments of a particular invention. Certain features described in this patent document in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any suitable sub-combination in multiple embodiments. Further, although a feature may be described above as acting in a certain combination and may even be claimed as such initially, one or more features from the claimed combination may in some cases be able to be deleted from the combination, and the claimed combination may be directed to a sub-combination or a variation of a sub-combination.

[0061] Likewise, although operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in a sequential order, or that all of the illustrated operations be performed, to achieve a desired result. Further, the separation of various system components in the embodiments described in this patent document should not be understood as requiring such separation in all embodiments.

[0062] Only some implementations and examples are described, and other implementations, enhancements, and variations can also be made based on what is described and illustrated in this patent document.

Claims

1. A method for wireless communication, comprising: transmitting, by a base station, system information to a terminal device, wherein the system information indicates whether a cell-defined synchronization signal block (SSB) or a non-cell-defined SSB is applicable for the terminal device with reduced capabilities to perform measurements, and the cell-defined SSB is an SSB associated with remaining minimum system information (RMSI).

2. A method for wireless communication, comprising: receiving, by a terminal device with reduced capabilities, from a base station, system information indicating whether a cell-defined synchronization signal block (SSB) or a non-cell-defined SSB is applicable, wherein the cell-defined SSB is an SSB associated with remaining minimum system information (RMSI), and performing measurements using the cell-defined SSB or the non-cell-defined SSB based on the system information.

3. The method according to any one of claims 1 or 2, wherein the system information is carried in a system information block (SIB) for intra-frequency measurements.

4. The method according to any one of claims 1 - 3, wherein the system information is carried in a SIB for inter-frequency measurements.

5. The method according to any one of claims 1 - 4, wherein in response to the non-cell-defined SSB being applicable, the non-cell-defined SSB is associated with cell group resources.

6. A method for wireless communication, comprising: receiving, by a base station, information indicating the reduced capabilities of a terminal device in a random access procedure.

7. A method for wireless communication, comprising: transmitting, by a terminal device, information indicating the reduced capabilities of the terminal device to a base station in a random access procedure.

8. The method according to claim 6 or 7, wherein the use of dedicated resources for Msg1 of the random access procedure indicates the reduced capabilities of the terminal device.

9. The method according to claim 8, wherein the information indicating the reduced capabilities is defined in a characteristic combination information element.

10. The method according to claim 6 or 7, wherein the information indicating the reduced capabilities is carried in Msg3 of the random access procedure.

11. ​ The method according to claim 10, wherein the information indicating the reduction ability is carried in the logical channel identifier value of the Msg3. **Claim 12** A method for wireless communication, the method includes transmitting, from a first node, configuration information about a non-cell-defined synchronization signal block (SSB) to neighboring nodes, the non-cell-defined SSB being an SSB not associated with remaining minimum system information (RMSI). **Claim 13** The method according to claim 12, wherein the configuration information comprises at least one of a carrier frequency for the non-cell-defined SSB or an SSB type. **Claim 14** The method according to claim 12, wherein the configuration information is carried in at least one of an access node configuration update confirmation response message, an Xn setup response message, or an Xn setup request message. **Claim 15** A communication device comprising a processor configured to implement the method according to any one or more of claims 1 - 14. **Claim 16** A computer program product having stored code, which, when executed by a processor, causes the processor to implement the method according to any one or more of claims 1 - 14.

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