WO2025210843A1 - Terminal device, base station device, and wireless communication system - Google Patents

Abstract

This terminal device transmits a PRACH to a base station device. The terminal device comprises: a reception unit that receives first information pertaining to a first RO that can be used by each of the terminal device and other terminal devices, and second information pertaining to a second RO that can be used by the terminal device and that is not available to the other terminal devices; a control unit that, in accordance with the second information or the first information and the second information, identifies the RO allocated to the terminal device from the first RO and the second RO; and a transmission unit that transmits the PRACH to the base station device via the identified RO.

Description

Terminal device, base station device, and wireless communication system

This disclosure relates to a terminal device, a base station device, and a wireless communication system.

In today's networks, traffic from mobile devices (smartphones and feature phones) accounts for the majority of network resources, and this trend is set to continue. In addition to traffic used by mobile devices, IoT (Internet of Things) services (such as transportation systems, smart meters, and device monitoring systems) are also being developed. Therefore, such networks are being required to support services with diverse requirements.

In order to accommodate such diverse services, fifth-generation mobile communications (5G, or NR (New Radio)) communication standards (e.g., Non-Patent Documents 1 to 14) have been developed to support a wide range of use cases, including eMBB (Enhanced Mobile Broadband), Massive MTC (Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communications).

Furthermore, the international standardization project, the 3rd Generation Partnership Project (3GPP (registered trademark)), is currently continuously studying and standardizing technologies to extend the above communication standards.

3GPP TS 37.324 V17.0.0 3GPP TS 37.340 V18.0.0 3GPP TS 38.201 V18.0.0 3GPP TS 38.202 V18.1.0 3GPP TS 38.211 V18.1.0 3GPP TS 38.212 V18.1.0 3GPP TS 38.213 V18.1.0 3GPP TS 38.214 V18.1.0 3GPP TS 38.215 V18.1.0 3GPP TS 38.300 V18.0.0 3GPP TS 38.321 V18.0.0 3GPP TS 38.322 V18.0.0 3GPP TS 38.323 V18.0.0 3GPP TS 38.331 V18.0.0

In a wireless communication system such as the one described above, for example, terminal devices compatible with NES (Network Energy Saving) cells and terminal devices that do not support NES cells may coexist. An NES cell is, for example, a cell to which technology that can reduce the power consumption of base station devices is applied. Technology that can reduce the power consumption of base stations includes, for example, adjusting the resource cycle and number of PRACH (Physical Random Access Channel) resources. Another technology that can reduce the power consumption of base stations includes, for example, muting PRACH resources. Muting PRACH resources means, for example, stopping reception on PRACH resources.

However, for example, the operating method when a terminal device corresponding to an NES cell and a terminal device not corresponding to an NES cell each perform a random access procedure (RACH: Random Access CHannel procedure) to an NES cell is still under consideration and has not yet been determined. Therefore, in a wireless communication system, for example, the results of mapping RO (Rach Occasion) and SSB (Synchronization Signal Block) may differ between a terminal device corresponding to an NES cell and a terminal device not corresponding to an NES cell, and one or more SSBs mapped by a terminal device corresponding to an NES cell in the same RO may differ from one or more SSBs mapped by a terminal device not corresponding to an NES cell. Therefore, in a wireless communication system, for example, a base station device that receives a PRACH (Physical Random Access Channel) may not be able to identify the SSB corresponding to the RO used to transmit the PRACH.

Therefore, one disclosure provides a terminal device, a base station device, and a wireless communication system that make it possible to identify the SSB corresponding to the RO used in transmitting the PRACH.

A terminal device that transmits a PRACH (Physical Random Access Channel) to a base station device includes: a receiver that receives first information regarding a first RO (Rach Occasion) that is available to the terminal device and other terminal devices; and second information regarding a second RO that is available to the terminal device but not the other terminal devices; a controller that identifies an RO assigned to the terminal device from the first RO and the second RO in accordance with the second information or the first information and the second information; and a transmitter that transmits the PRACH to the base station device via the identified RO.

One disclosure makes it possible to identify the SSB corresponding to the RO used to transmit the PRACH.

FIG. 1 is a diagram showing an example of the configuration of a wireless communication system 10. FIG. 2 is a diagram illustrating an example of the configuration of the terminal device 100. As shown in FIG. FIG. 3 is a diagram illustrating an example of the configuration of the base station device 200. FIG. 4 is a diagram illustrating a specific example of RO. FIG. 5 is a diagram illustrating a specific example of RO. FIG. 6 is a diagram illustrating a specific example of RO. FIG. 7 is a diagram illustrating a specific example of RO. FIG. 8 illustrates an example of a sequence of a mapping control process according to the first embodiment. FIG. 9 illustrates an example of a sequence of a mapping control process according to the first embodiment. FIG. 10 is a diagram illustrating a specific example of RO. FIG. 11 is a diagram illustrating a specific example of RO. FIG. 12 is a diagram illustrating a specific example of RO. FIG. 13 is a diagram illustrating a specific example of RO. FIG. 14 illustrates an example of a sequence of a mapping control process according to the first embodiment. FIG. 15 is a diagram illustrating a specific example of RO. FIG. 16 is a diagram illustrating a specific example of RO. FIG. 17 is a diagram illustrating a specific example of RO. FIG. 18 is a diagram illustrating a specific example of RO. FIG. 19 is a diagram illustrating a specific example of RO. FIG. 20 is a diagram illustrating a specific example of RO. FIG. 21 is a diagram illustrating a specific example of RO.

Embodiments of the present disclosure will be described below with reference to the drawings. However, such descriptions should not be construed in a limiting sense, and do not limit the subject matter described in the claims. Furthermore, various changes, substitutions, and modifications can be made without departing from the spirit and scope of the present disclosure. Different embodiments can also be combined as appropriate.

[First embodiment]
(Regarding the wireless communication system 10)
1 is a diagram showing an example of the configuration of a wireless communication system 10. The wireless communication system 10 includes, for example, a terminal device 100a, a terminal device 100b, and a base station device 200. Hereinafter, the terminal device 100a and the terminal device 100b will also be collectively referred to simply as the terminal device 100.

The terminal device 100a is, for example, a communications device that wirelessly connects to the base station device 200 and transmits and receives data. Specifically, the terminal device 100a is, for example, a UE (User Equipment) such as a smartphone or tablet terminal. The terminal device 100a is, for example, a terminal device 100 that corresponds to an NES cell. Hereinafter, the terminal device 100a will also be referred to as an NES Capable UE. Hereinafter, the terminal device 100a will also be referred to simply as an NES.

The terminal device 100b is, for example, a communication device that is wirelessly connected to the base station device 200 and transmits and receives data. Specifically, the terminal device 100b is, for example, a UE (User Equipment) such as a smartphone or tablet terminal. The terminal device 100b is, for example, a terminal device 100 that does not support an NES cell. Hereinafter, the terminal device 100b is also referred to as a Legacy UE. Hereinafter, the terminal device 100b is also simply referred to as a LEG.

The base station device 200 is, for example, a device that wirelessly connects to the terminal device 100 and transmits and receives data. Specifically, the base station device 200 is, for example, an eNodeB or gNodeB. The base station device 200 supports, for example, various communication generations (e.g., 4G, 5G, Beyond 5G, or 6G, etc.). Furthermore, the base station device 200 may be, for example, configured as a single unit, or may be configured as multiple units such as a CU (Central Unit) or DU (Distributed Unit).

(Configuration example of terminal device 100)
2 is a diagram showing an example of the configuration of the terminal device 100. The terminal device 100 includes, for example, a CPU (Central Processing Unit) 110, a storage 120, a memory 130, and a wireless communication circuit 150.

Storage 120 is, for example, an auxiliary storage device that stores programs and data, such as a flash memory, HDD (Hard Disk Drive), or SSD (Solid State Drive). Storage 120 stores, for example, a terminal communication program 121 and a mapping control program 122.

Memory 130 is, for example, an area into which programs stored in storage 120 are loaded. Note that memory 130 may also be used, for example, as an area in which programs store data.

The wireless communication circuit 150 is, for example, a circuit that performs wireless communication with the base station device 200. The wireless communication circuit 150 has, for example, an antenna 151. The antenna 151 includes, for example, a directional antenna that can control the direction of transmission and reception of radio waves. The wireless communication circuit 150 is also capable of changing the transmission power, for example.

The CPU 110 is a processor that constructs each component and performs each process, for example, by loading programs stored in the storage 120 into the memory 130 and executing them.

The CPU 110, for example, executes the terminal communication program 121 to construct a receiving unit and a transmitting unit and perform terminal communication processing. The terminal communication processing is processing to establish a wireless connection with the base station device 200 and perform wireless communication.

The CPU 110, for example, executes the mapping control program 122 to construct a mapping control unit (hereinafter simply referred to as the control unit) and perform mapping control processing. The mapping control processing is a process that performs mapping (association) between, for example, RO (Ratch Occasion) and SSB (Synchronization Signal Block).

(Configuration example of base station device 200)
3 is a diagram showing an example of the configuration of the base station device 200. The base station device 200 includes, for example, a CPU 210, a storage 220, a memory 230, and a wireless communication circuit 250.

Storage 220 is, for example, an auxiliary storage device that stores programs and data, such as flash memory, HDD, or SSD. Storage 220 stores, for example, a base station communication program 221.

Memory 230 is, for example, an area into which programs stored in storage 220 are loaded. Note that memory 230 may also be used, for example, as an area in which programs store data.

The wireless communication circuit 250 is, for example, a device that performs wireless communication with the terminal device 100. The wireless communication circuit 250 has, for example, an antenna 251. The antenna 251 includes, for example, a directional antenna that can control the direction of transmission and reception of radio waves.

The CPU 210 is a processor that constructs each component and performs each process, for example, by loading a program stored in the storage 220 into the memory 230 and executing it.

The CPU 210, for example, executes the base station communication program 221 to construct a receiving unit and a transmitting unit and perform base station communication processing. The base station communication processing is processing for wireless communication with the terminal device 100. Specifically, during the base station communication processing, the base station device 200 establishes a wireless connection with the terminal device 100, transmits data to the terminal device 100, and receives data from the terminal device 100.

(Specific example of RO)
Next, specific examples of RO will be described. Figures 4 to 7, 10 to 13, and 15 to 18 are diagrams for explaining specific examples of RO. In Figures 4 to 7, 10 to 13, and 15 to 18, the horizontal axis corresponds to time and the vertical axis corresponds to frequency.

The base station device 200 broadcasts, for example, information related to ROs. The information related to ROs includes, for example, information on time domain resources, information on frequency domain resources, the number of SSBs allocated per RO, and the number of preambles for each SSB per RO. The information on time domain resources is provided, for example, by a PRACH Configuration Index. The information on frequency domain resources is provided, for example, by the number of FDMs (Frequency Division Multiplex). The number of FDMs is the number of ROs allocated at the same time.

Specifically, the base station device 200 broadcasts information (hereinafter also referred to as first information) regarding an RO (hereinafter also referred to as first RO) that can be used when transmitting a PRACH by, for example, a terminal device corresponding to the NES cell (e.g., terminal device 100a) and a terminal device not corresponding to the NES cell (e.g., terminal device 100b).

The base station device 200 also broadcasts information (hereinafter also referred to as second information) regarding an RO (hereinafter also referred to as second RO) that can be used when a terminal device corresponding to the NES cell (e.g., terminal device 100a) transmits a PRACH, but cannot be used when a terminal device not corresponding to the NES cell (e.g., terminal device 100b) transmits a PRACH.

Note that, hereinafter, resources corresponding to the first RO will also be referred to as resources LR, and resources corresponding to the second RO will also be referred to as resources AR. That is, in the example shown in FIG. 4, the ROs included in resource LR1 ("RO0", "RO1", "RO2", and "RO3") and the ROs included in resource LR2 ("RO8", "RO9", "RO10", and "RO11") are first ROs. Also, in the example shown in FIG. 4, the ROs included in resource AR1 ("RO4", "RO5", "RO6", and "RO7") and the ROs included in resource AR2 ("RO12", "RO13", "RO14", and "RO15") are second ROs.

Here, the terminal device 100a is, for example, a terminal device 100 that can recognize each of the first information and the second information. In other words, the terminal device 100a is, for example, a terminal device 100 that can transmit a PRACH by using each of the first RO and the second RO. Therefore, when mapping ROs and SSBs, the terminal device 100a maps each SSB to "RO0," "RO1," "RO2," "RO3," "RO4," "RO5," "RO6," "RO7," "RO8," "RO9," "RO10," "RO11," "RO12," "RO13," "RO14," and "RO15," as shown in FIG. 5.

Specifically, for example, when the number of SSBs allocated per RO is set to 1, the terminal device 100a, as shown in FIG. 5, sequentially associates "SSB0", "SSB1", "SSB2", "SSB3", "SSB4", "SSB5", "SSB6", and "SSB7" with "RO0", "RO1", "RO2", "RO3", "RO4", "RO5", "RO6", and "RO7", respectively. Furthermore, the terminal device 100a sequentially associates "SSB0", "SSB1", "SSB2", "SSB3", "SSB4", "SSB5", "SSB6", and "SSB7" with "RO8", "RO9", "RO10", "RO11", "RO12", "RO13", "RO14", and "RO15", respectively.

In contrast, terminal device 100b is, for example, a terminal device 100 that can recognize the first information but cannot recognize the second information due to differences in the supported program versions. In other words, terminal device 100b is, for example, a terminal device 100 that can transmit PRACH using the first RO but cannot transmit PRACH using the second RO. Therefore, when terminal device 100b maps ROs to SSBs, for example, it maps each SSB to "RO0," "RO1," "RO2," "RO3," "RO8," "RO9," "RO10," and "RO11," as shown in FIG. 6.

Specifically, as shown in FIG. 6, the terminal device 100a associates, in order, "RO0," "RO1," "RO2," "RO3," "RO8," "RO9," "RO10," and "RO11," respectively, with "SSB0," "SSB1," "SSB2," "SSB3," "SSB4," "SSB5," "SSB6," and "SSB7."

In other words, when RO and SSB are mapped in each of terminal device 100a and terminal device 100b, there is a possibility that the SSB mapped by terminal device 100a and the SSB mapped by terminal device 100b will differ for some ROs.

Specifically, for example, if the mapping shown in Figures 5 and 6 is performed in terminal device 100a and terminal device 100b, respectively, in the wireless communication system 10, as shown in Figure 7, the SSBs mapped to "RO8," "RO9," "RO10," and "RO11" will differ depending on the terminal device 100. Therefore, in the wireless communication system 10, for example, the base station device 200 that receives the PRACH may not be able to identify the SSB corresponding to the RO used to transmit the PRACH.

(Mapping Control Process in the First Embodiment)
Next, the mapping control process in the first embodiment will be described. Fig. 8 is a diagram showing an example of the sequence of the mapping control process in the first embodiment. Figs. 9 and 14 are flowcharts of the mapping control process in the first embodiment. Figs. 10 to 13 and 15 to 18 are diagrams for explaining the mapping control process in the first embodiment.

The terminal device 100a, for example, measures the RSRP (Reference Signal Received Power) of one or more SSBs broadcast from the base station device 200 (S11).

Then, the terminal device 100a performs a process (hereinafter also referred to as an SSB selection process) to select, for example, an SSB with the highest measured RSRP from one or more SSBs (S12).

Next, the terminal device 100a receives, for example, notification information broadcast from the base station device 200 (S13). The notification information is, for example, information transmitted via SIB1 (System Information Block Type 1). The notification information is, for example, RRC information. The RRC information is, for example, information included in RRCReconfiguration, RRCResume, RRCSetup, or ReconfigurationWithSync. Specifically, the notification information may include, for example, first information and second information. Note that the first information and the second information may each include, for example, different notification information.

Then, the terminal device 100a performs, for example, a process of determining the position (time position and frequency position) of each RO (hereinafter also referred to as RO position determination process) (S14).

Specifically, the terminal device 100a determines the time position of each RO by, for example, referring to the time domain resource information included in the first information and the second information. Furthermore, the terminal device 100a determines the frequency position of each RO by, for example, referring to the frequency domain resource information included in the first information and the second information.

Next, the terminal device 100a performs a process (hereinafter also referred to as a mapping process) to map the first RO and the second RO to the SSB (S15).

Then, the terminal device 100a transmits a PRACH to the base station device 200, for example, in the RO corresponding to the SSB selected in S12 (S16).

Specifically, for example, in S16, the terminal device 100a transmits the PRACH by using a preamble randomly selected from the preambles mapped in S15 corresponding to the selected RO. Furthermore, for example, the terminal device 100a transmits the PRACH using a preamble specified in the notification information transmitted from the base station device 200.

(Details of S15 (1))
Next, details of S15 will be described. Fig. 9 is a flowchart illustrating a first specific example (hereinafter simply referred to as the first specific example) of the details of S15. Figs. 10 to 12 are diagrams illustrating the first specific example.

As shown in FIG. 9, the terminal device 100a, for example, maps each of the first ROs to an SSB (S15-1). That is, the terminal device 100a maps, for example, an RO that can be used by a terminal device 100 that does not support NES (for example, terminal device 100b) to an SSB. In other words, the terminal device 100a performs the same mapping as that performed by a terminal device 100 that does not support NES (for example, terminal device 100b). Hereinafter, the result of the same mapping as that performed by a terminal device 100 that does not support NES (for example, terminal device 100b) is also referred to as NES1.

Specifically, as shown in FIG. 10, for example, terminal device 100a associates "SSB0", "SSB1", "SSB2", "SSB3", "SSB4", "SSB5", "SSB6", and "SSB7" in order with "RO0", "RO1", "RO2", and "RO3", which are ROs included in resource LR21, and "RO8", "RO9", "RO10", and "RO11", which are ROs included in resource LR22. Note that the example shown in FIG. 10 is an example in which SSBs corresponding to one mapping cycle are associated.

Next, the terminal device 100a performs, for example, mapping between the first RO and the second RO and the SSB (S15-2). That is, the terminal device 100a performs, for example, mapping between the ROs that the terminal device 100a can use and the SSB. Hereinafter, the result of the mapping performed by the terminal device 100a is also referred to as NES2.

Specifically, as shown in FIG. 4, terminal device 100a associates SSB with, for example, ROs "RO0," "RO1," "RO2," and "RO3" included in resource LR21, ROs "RO4," "RO5," "RO6," and "RO7" included in resource AR21, ROs "RO8," "RO9," "RO10," and "RO11" included in resource LR22, and ROs "RO12," "RO13," "RO14," and "RO15" included in resource AR22.

Next, the terminal device 100a performs mapping in each RO, for example, and then compares the results with the mapping results performed in the same RO in S15-1 (S15-3).

Then, the terminal device 100a identifies a valid RO (a valid RO for its own device) by, for example, comparing the mapping results. Unless the mapping results are different, it identifies the RO as valid (S15-4).

Specifically, for example, as shown in FIG. 11, after performing mapping with "RO0," the terminal device 100a compares the mapping results with those performed with "RO0" in S15-1, and since the mapping results are the same, identifies "RO0" as a valid RO. Then, for example, using the same procedure, the terminal device 100a identifies "RO1," "RO2," and "RO3" as valid ROs, as shown in FIG. 11.

Furthermore, as shown in FIG. 11, after performing mapping with "RO4," the terminal device 100a compares the results of the mapping performed with "RO4" in S15-1, and since there is no mapping result with "RO4" in S15-1, it identifies "RO4" as a valid RO. Then, using the same procedure, the terminal device 100a identifies "RO5," "RO6," and "RO7" as valid ROs, for example, as shown in FIG. 11.

Furthermore, as shown in FIG. 11, after performing mapping with "RO8", for example, the terminal device 100a compares the results of the mapping performed with "RO8" in S15-1 and, since the results are different from the mapping results with "RO8" in S15-1, does not identify "RO8" as a valid RO.

In this way, as shown in FIG. 12, the terminal device 100a identifies, for example, "RO0," "RO1," "RO2," "RO3," "RO4," "RO5," "RO6," "RO7," "RO12," "RO13," "RO14," and "RO15" as valid ROs and associates them with SSBs. In other words, as shown in FIG. 12, the terminal device 100a identifies, for example, ROs other than "RO8," "RO9," "RO10," and "RO11" as valid ROs and associates them with SSBs.

In this way, the terminal device 100a in this embodiment receives, for example, first information regarding a first RO that is available to each of the terminal device 100a and the terminal device 100b, and second information regarding a second RO that is available to the terminal device 100a but not to the terminal device 100b. Then, the terminal device 100a in this embodiment identifies an RO assigned to the terminal device 100a from the first RO and the second RO, for example, in accordance with the first information and the second information. Thereafter, the terminal device 100a in this embodiment transmits a PRACH to the base station device 200 via the identified RO, for example.

In other words, the terminal device 100a will not consider an RO in which the mapping results performed by the terminal device 100a and the mapping results performed by the terminal device 100b are different as a valid RO.

This enables the wireless communication system 10 to perform control so that, for example, one or more SSBs mapped by terminal device 100a and one or more SSBs mapped by terminal device 100b in the same RO do not differ. Therefore, in the wireless communication system 10, it becomes possible to prevent, for example, a situation from occurring in which the base station device 200 that receives a PRACH is unable to identify the SSBs corresponding to the RO used to transmit the PRACH.

Note that, for example, if a first RO exists that is also a second RO (hereinafter also referred to as an overlapping RO), the terminal device 100a may map the RO other than the overlapping RO between the first RO and the second RO and the SSB in S15-2. Specifically, for example, the terminal device 100a does not identify as a valid RO.

(Details of S15 (2))
Fig. 14 is a flowchart illustrating a second specific example (hereinafter simply referred to as the second specific example) of the details of S15. Figs. 15 to 17 are diagrams illustrating the second specific example.

As shown in FIG. 14, the terminal device 100a, for example, maps each of the first ROs to an SSB (S15-5). That is, the terminal device 100a performs the same process as S15-1, for example.

Specifically, as shown in FIG. 15, for example, the terminal device 100a associates "SSB0", "SSB1", "SSB2", "SSB3", "SSB4", "SSB5", "SSB6", and "SSB7" in order with "RO0", "RO1", "RO2", and "RO3" that are ROs included in resource LR31, and "RO8", "RO9", "RO10", and "RO11" that are ROs included in resource LR32. Note that the example shown in FIG. 15 is an example in which SSBs corresponding to one mapping cycle are associated.

Next, the terminal device 100a, for example, maps each of the second ROs to an SSB (S15-6). That is, the terminal device 100a maps, for example, an RO that cannot be used by a terminal device 100 that does not support NES (for example, terminal device 100b) to an SSB.

Specifically, as shown in FIG. 16, for example, the terminal device 100a associates "SSB0", "SSB1", "SSB2", "SSB3", "SSB4", "SSB5", "SSB6", and "SSB7" in order with "RO4", "RO5", "RO6", and "RO7" which are ROs included in resource AR31, and "RO12", "RO13", "RO14", and "RO15" which are ROs included in resource AR32. Note that the example shown in FIG. 16 is an example in which SSBs corresponding to one mapping cycle are associated.

Then, the terminal device 100a associates the SSB with, for example, the first RO and the second RO, as shown in FIG. 17.

This enables the wireless communication system 10 to perform control so that, for example, one or more SSBs mapped by terminal device 100a and one or more SSBs mapped by terminal device 100b in the same RO do not differ. Therefore, in the wireless communication system 10, it is possible to prevent, for example, a situation from occurring in which the base station device 200 that has received a PRACH is unable to identify the type of terminal device 100 that is the PRACH sender or the SSB corresponding to the RO used to transmit the PRACH.

Note that, for example, if a duplicate RO exists, the terminal device 100a may map the ROs other than the duplicate RO among the second ROs to the SSB in S15-6. Specifically, for example, the terminal device 100a does not identify as a valid RO.

Second Embodiment
Next, a second embodiment will be described.

In this embodiment, the terminal device 100a transmits the PRACH by using a preamble designated in advance by the base station device 200 from among the preambles available for use in the SSB selected in S12, etc.

Specifically, the terminal device 100a receives, for example, information indicating a preamble transmitted from the base station device 200 (hereinafter referred to as third information). Then, for example, as shown in FIG. 8, the terminal device 100a identifies the preamble indicated by the third information received from the base station device 200 from among the preambles available for use in the SSB selected in S12, etc. Note that the terminal device 100a transmits the PRACH by using, for example, a preamble selected randomly from the identified preambles. Note that the third information may be included, for example, in notification information broadcast from the base station device 200. The terminal device 100a may also transmit the PRACH using, for example, the identified preamble.

More specifically, the third information includes the number of preambles (hereinafter simply referred to as the number of preambles) available to the terminal device 100 (e.g., terminal device 100a) corresponding to the NES, and the first index (hereinafter simply referred to as the first index) of the preambles available to the terminal device 100 (e.g., terminal device 100a) corresponding to the NES. The terminal device 100a then specifies, for example, a range equal to or greater than the first index and less than the index corresponding to the sum of the first index and the number of preambles, as the range of indexes for preambles available to the terminal device itself. The terminal device 100a may transmit the PRACH by using, for example, a preamble randomly selected from the preambles included in the specified range. The terminal device 100a may also transmit the PRACH using, for example, the specified preamble.

As a result, the base station device 200 can, for example, by referencing the preamble corresponding to the PRACH, identify the SSB corresponding to the RO used to transmit the PRACH. The base station device 200 can also, for example, identify the type of terminal device 100 that is the source of the PRACH.

[Third embodiment]
Next, a third embodiment will be described. Figures 18 to 21 are diagrams for explaining specific examples of RO in the third embodiment.

In this embodiment, the terminal device 100a associates the first RO and the second RO with the SSB so that, for example, the number of times the SSB mapping cycle is executed within the configuration period (hereinafter simply referred to as the configuration period) of the first RO is a predetermined integer number (hereinafter also referred to as the first integer number), and the number of times the SSB mapping cycle is executed within the configuration period of the second RO is another integer number (hereinafter also referred to as the second integer number). Each of the first integer number and the second integer number may be, for example, one or more.

Specifically, in this embodiment, the terminal device 100a controls the number of SSB mapping cycles executed within the setting period of the first RO to be a first integer number, and controls the number of SSB mapping cycles executed within the setting period of the second RO to be a second integer number, for example, by referring to the number of SSBs allocated per RO included in the first information and the second information.

More specifically, in the example shown in FIG. 18, for example, each RO included in resource LR41 ("RO0", "RO1", "RO2", and "RO3"), each RO included in resource AR41 ("RO4", "RO5", "RO6", and "RO7"), each RO included in resource LR42 ("RO8", "RO9", "RO10", and "RO11"), and each RO included in resource AR42 ("RO12", "RO13", "RO14", and "RO15") each fall within the set period.

Therefore, in this case, the terminal device 100a performs mapping to associate "SSB0", "SSB1", "SSB2", "SSB3", "SSB4", "SSB5", "SSB6", and "SSB7", which correspond to one mapping cycle, with each RO, for example, in the setting period consisting of resource LR41, the setting period consisting of resource AR41, the setting period consisting of resource LR42, and the setting period consisting of resource AR42.

Furthermore, in this case, terminal device 100b performs mapping that associates "SSB0," "SSB1," "SSB2," "SSB3," "SSB4," "SSB5," "SSB6," and "SSB7," which correspond to one mapping cycle, with each RO, for example, during the setting period consisting of resource LR41 and the setting period consisting of resource LR42.

In the example shown in FIG. 19, each of the ROs included in resources LR51 and LR52 ("RO0", "RO1", "RO2", "RO3", "RO4", "RO5", "RO6", and "RO7"), each of the ROs included in resources AR51 and AR52 ("RO8", "RO9", "RO10", "RO11", "RO12", "RO13", "RO14", and "RO15"), and each of the ROs included in resources LR53 and LR54 ("RO16", "RO17", "RO18", "RO19", "RO20", "RO21", "RO22", and "RO23") each fall within the set period.

Therefore, in this case, terminal device 100a performs mapping to associate "SSB0", "SSB1", "SSB2", "SSB3", "SSB4", "SSB5", "SSB6", and "SSB7", which correspond to one mapping cycle, with each RO, for example, in the setting period consisting of resource LR51 and resource LR52, the setting period consisting of resource AR51 and resource AR52, and the setting period consisting of resource LR53 and resource LR54.

Furthermore, in this case, terminal device 100b performs mapping that associates "SSB0," "SSB1," "SSB2," "SSB3," "SSB4," "SSB5," "SSB6," and "SSB7," which correspond to one mapping cycle, with each RO, for example, in a setting period consisting of resource LR51 and resource LR52 and a setting period consisting of resource LR53 and resource LR54.

This enables the wireless communication system 10 to perform control so that, for example, one or more SSBs mapped by the terminal device 100a and one or more SSBs mapped by the terminal device 100b in the same RO do not differ. Therefore, the wireless communication system 10 can prevent, for example, a situation from occurring in which the base station device 200 that receives a PRACH is unable to identify the SSBs corresponding to the RO used to transmit the PRACH.

Note that, for example, from the perspective of reducing power consumption, the base station device 200 can adjust the second RO setting period or the number of ROs included in the second RO, or mute some of the second ROs. Muting some of the second ROs means stopping reception on some of the second ROs.

Specifically, as shown in FIG. 20, the base station device 200 can, for example, mute each RO within resource AR51. To this end, the base station device 200 notifies the terminal device 100a that each RO within resource AR51 will be muted, for example, using an RRC message, MAC-CE (MAC Control Element), or DCI (Downlink Control Information). Furthermore, as shown in FIG. 21, the base station device 200 can, for example, transmit first information that does not include information regarding each RO within resource AR51, or omit transmitting the first information.

In the example shown in FIG. 20, for example, in resource LR53 and resource LR54, the SSB corresponding to a terminal device 100 that supports NES (e.g., terminal device 100a) is different from the SSB corresponding to a terminal device 100 that does not support NES (e.g., terminal device 100b). On the other hand, in the example shown in FIG. 21, for example, in resource LR53 and resource LR54, the SSB corresponding to a terminal device 100 that supports NES (e.g., terminal device 100a) is not different from the SSB corresponding to a terminal device 100 that does not support NES (e.g., terminal device 100b).

Therefore, when the base station device 200 notifies that a portion of the second RO will be performed, it notifies that the RO within the resource AR included in an integer number of setting periods (e.g., one) will be muted, as shown in FIG. 21. Furthermore, the base station device 200 notifies that the second RO corresponding to an integer number of mapping cycles (e.g., one) will be muted, for example.

Specifically, the base station device 200, for example, includes information regarding RO adjustment in the second information and notifies the terminal device 100a. The information regarding RO adjustment is information including, for example, the setting period of the second RO, the number of ROs corresponding to the second RO, and at least one pattern for muting some of the second ROs. A pattern for muting some of the second ROs is, for example, muting second ROs corresponding to an integer number of mapping cycles (for example, one). A pattern for muting some of the second ROs is, for example, muting second ROs included in an integer number of setting periods (for example, one).

Then, the base station device 200 notifies the terminal device 100a of the second RO configuration period to be applied to the terminal device 100a, or/and the number of ROs corresponding to the second ROs, or/and a pattern for muting some of the second ROs, using, for example, an RRC message, MAC-CE (MAC Control Element), or DCI (Downlink Control Information).

As a result, even when the wireless communication system 10 transmits first information that omits information related to at least some of the resources AR, it is possible to prevent a situation from occurring in which the base station device 200 that receives the PRACH is unable to identify the SSB corresponding to the RO used to transmit the PRACH.

[Modifications of the first to third embodiments]
Next, modifications of the first to third embodiments will be described.

The terminal device 100a may, for example, not identify an RO previously designated by the base station device 200 as a valid RO.

Specifically, the terminal device 100a may receive, for example, information indicating an RO (hereinafter referred to as fourth information) transmitted from the base station device 200. Then, the terminal device 100a may identify, for example, an RO other than the RO indicated by the fourth information as a valid RO for the terminal device 100a.

10: Wireless communication system 100: Terminal device 100a: Terminal device 100b: Terminal device 110: CPU
120: Storage 121: Terminal communication program 122: Mapping control program 130: Memory 150: Wireless communication circuit 151: Antenna 200: Base station device 210: CPU
220: Storage 221: Base station communication program 230: Memory 250: Wireless communication circuit 251: Antenna

Claims (8)

A terminal device that transmits a PRACH (Physical Random Access CHannel) to a base station device,
a receiving unit that receives first information regarding a first RO (Reach Occasion) that is available to each of the terminal device and another terminal device, and second information regarding a second RO that is available to the terminal device but not to the other terminal device;
a control unit that identifies an RO assigned to the terminal device from the first RO and the second RO according to the second information or the first information and the second information;
a transmitter that transmits the PRACH to the base station device via the specified RO,
Terminal device. The control unit
Identifying a specific RO among the first RO and the second RO, in which an SSB (Synchronization Signal Block) associated with each RO by the terminal device is different from the SSB associated with each RO by the other terminal device;
Identifying an RO other than the identified specific RO as the RO assigned to the terminal device;
The terminal device according to claim 1 . The control unit
Associating the SSB corresponding to a first mapping cycle with the first RO;
Associating the second RO with the SSB corresponding to a second mapping cycle different from the first mapping cycle;
The terminal device according to claim 2 . the receiving unit receives third information related to a preamble from the base station device;
the transmitter transmits the PRACH to the base station device by using a preamble corresponding to the third information.
The terminal device according to claim 1 . the control unit associates the first RO and the second RO with the SSB so that the number of times a mapping cycle of the SSB is executed within a setting period of the first RO is a first integer number, and the number of times a mapping cycle of the SSB is executed within a setting period of the second RO is a second integer number;
The terminal device according to claim 1 . the receiving unit receives, from the base station device, fourth information indicating a specific RO that cannot be assigned to the terminal device;
The control unit identifies an RO other than the specific RO indicated by the fourth information as the RO assigned to the terminal device.
The terminal device according to claim 1 . a transmitter that transmits first information regarding a first RO that is available to each of a first terminal device and a second terminal device, and second information regarding a second RO that is available to the first terminal device but not to the second terminal device;
A receiving unit that receives a PRACH from the first terminal device via the second information or an RO specified according to the first information and the second information.
Base station equipment. A wireless communication system having a first terminal device and a base station device,
The base station device includes a transmitter that transmits first information regarding a first RO that is available to each of the first terminal device and the second terminal device, and second information regarding a second RO that is available to the first terminal device but not the second terminal device;
The first terminal device
Identifying an RO assigned to the first terminal device from the first RO and the second RO according to the second information or the first information and the second information;
Transmitting a PRACH (Physical Random Access Channel) to the base station device via the identified RO;
Wireless communication system.