Wireless communication method, user terminal and base station

Abstract

A base station transmits a first control signal for controlling transmission of notification data to a plurality of terminals, a second control signal related to communication between the terminals, and a data packet containing the data. A terminal demodulates the data packet based on the first control signal, and in a case where the demodulation of the data packet is successful, transmits a second data packet containing the data of which the demodulation is successful to other terminals in a radio resource based on the second control signal. On the other hand, in a case where the demodulation of the data packet is unsuccessful, the terminal receives and demodulates the second data packet transmitted by the other terminals in the radio resource based on the second control signal, and takes the data obtained by the demodulation as the data contained in the data packet of which the demodulation is unsuccessful.

Description

Technical Field

[0001] This disclosure relates to wireless communication methods, user terminals, and base stations. Background Technology

[0002] Developed as a system that enables voice calls while on the move, cellular wireless communication systems are not limited to locations connected by telephone lines. Currently, they are used not only for voice calls but also in a wide variety of services that flexibly utilize information communication. Furthermore, their use is expanding beyond human devices to include industrial applications such as remote operation of various sensors and industrial machinery.

[0003] In cellular wireless communication systems, base stations are set up in fixed service areas, and terminals communicate with the nearest base station. However, cellular wireless communication systems cannot be used in locations such as mountainous areas, at sea, and inside aircraft where it is difficult to set up base stations due to cost or physical limitations. Therefore, in recent years, consideration has been given to using artificial satellites or high-altitude aircraft (hereinafter, in this disclosure, the term "satellite" is used to include both artificial satellites and high-altitude aircraft) equipped with the base station function of cellular wireless communication systems, thereby enabling the use of cellular wireless communication systems in various locations on Earth. While satellite-based communication is currently in use, the ability to utilize it as a cellular wireless communication system allows for the continued use of the diverse services offered by cellular wireless communication systems developed through terrestrial base stations, making it highly valuable. Furthermore, satellite-based cellular wireless communication systems are also effective as an emergency communication means when terrestrial base stations are unavailable due to disasters or other reasons.

[0004] Among the various services utilizing cellular wireless communication systems, broadcast reception, downloading popular content, and system updates for terminals and PCs and industrial equipment using these terminals as communication tools are frequently performed, often involving the simultaneous distribution of the same content to multiple terminals. To provide this service, distribution via a communication channel (hereinafter referred to as a "broadcast channel") dedicated to multiple, specific or unspecified terminals is more efficient than distribution via dedicated channels for each terminal. Satellites, with their wider coverage and ability to provide communication to more terminals than terrestrial base stations, are highly adaptable to these types of communication.

[0005] In cellular wireless communication systems, terminals connect to base stations and communicate with them under the control of the base stations. Therefore, communication between terminals is generally not performed. However, inter-terminal communication is supported in the cellular wireless communication system standards defined by the 3rd Generation Partnership Project (3GPP, a registered trademark) in version 12 and later, finalized in 2013. The 3GPP standards specify two methods for inter-terminal communication: one where the terminal communicates with other terminals under the control of the base station within radio resources indicated by the base station; and another where the terminal autonomously selects radio resources for inter-terminal communication. The former method minimizes interference between inter-terminal communication and existing communication between the base station and the terminal, while the latter method enables inter-terminal communication even in environments where communication with the base station is impossible. In the 2023 version 18 standard specification, inter-terminal communication using unlicensed frequency bands is supported. Before inter-terminal communication, the terminals use CSMA-CA (Carrier Sense Multiple Access - Collision Avoidance) to determine whether the frequency band to be used for inter-terminal communication is being used by other terminals. If it is determined that the frequency band is not being used, inter-terminal communication is carried out.

[0006] A terminal that autonomously selects radio resources for inter-terminal communication within a licensed frequency band according to the 3GPP standards for cellular wireless communication systems sets a selection window (for selecting the range of radio resources to transmit from) and a sensing window (for monitoring the usage of radio waves for this selection) before transmitting. Within the sensing window, the terminal monitors control information for communications conducted by other terminals and collects reservation information for radio resources to be used by other terminals currently communicating. Then, within the selection window, it selects a radio resource with no reservation information or reservation information related to terminals with weak signal strength, and uses that radio resource for transmission.

[0007] In wireless link design for cellular wireless communication systems, control is performed to suppress transmission power to the minimum necessary level. The first reason is to reduce interference to communications that use the same frequency. In cellular wireless communication systems, to use frequency resources efficiently and flexibly, frequencies identical to those used in a certain area are reused in different areas. If the transmission power is unnecessarily high, it will cause interference to other communications using the same frequency and degrade communication quality. Therefore, the transmission power is controlled to the minimum necessary level so that each communication using the same frequency can be performed at a satisfactory quality. The second reason is to reduce power consumption of base stations or terminals. It goes without saying that low power consumption of wireless devices is a requirement for building a low-carbon society, and it is an important issue for terminals and base stations mounted on satellites to effectively utilize the limited power of rechargeable batteries or solar cells.

[0008] The transmission power of a cellular wireless communication system is controlled, for example, such that the block error rate when receiving and decoding data packets is, for example, 10. This represents the probability that 9 / 10 of the received data packets are normally received and 1 / 10 are received in error. For erroneous data packets, the transmission source is requested to perform retransmission. Thereby, the total transmission power is minimized.

[0009] Prior Art Literature

[0010] Non-Patent Literature

[0011] Non-Patent Literature 1: M.H.C. Garcia et al., "A Tutorial on 5G NR V2X Communications," in IEEE Communications Surveys & Tutorials, vol. 23, no. 3, pp. 1972-2026, third quarter 2021, <URL: https: / / doi.org / 10.1109 / COMST.2021.<3057017> Contents of the Invention

[0012] Problems to be Solved by the Invention

[0013] ​When transmitting data packets via a broadcast channel for multiple terminals from a receiving terminal, consider the case where transmission power is required to meet the specified reception quality for all terminals. However, in this method, the transmission power needs to be adjusted to ensure sufficient signal strength for the terminal with the worst or expected poor reception quality, leading to an increase in the required transmission power. Furthermore, even if multiple terminals receiving the broadcast channel have the same level of reception quality (i.e., the same block error rate), if the instantaneous noise and interference conditions differ among the terminals, reception errors will occur for different data packets. If the terminals request retransmissions of different data packets from the base station (the transmitting source), the base station will retransmit more data packets, resulting in increased power consumption.

[0014] One aspect of this disclosure is to provide a wireless communication technology capable of suppressing power consumption.

[0015] Methods for solving problems

[0016] One of the methods disclosed herein is a wireless communication method between a base station and a terminal, which includes:

[0017] In the first sending step, the base station sends a first control signal for sending notification data and a second control signal related to inter-terminal communication to multiple terminals.

[0018] In the second transmission step, the base station transmits data packets containing the data to the plurality of terminals.

[0019] The demodulation step involves the terminal demodulating the data packet according to the first control signal.

[0020] Inter-terminal transmission step, in which, if the data packet is successfully demodulated, the terminal transmits a second data packet containing the successfully demodulated data to other terminals in radio resources based on the second control signal; and

[0021] In the inter-terminal reception step, if the demodulation of the data packet fails, the terminal receives and demodulates the second data packet sent by another terminal in the radio resources based on the second control signal, and uses the data obtained through demodulation as the data contained in the data packet that failed to be demodulated.

[0022] Another aspect of this disclosure is a user terminal that includes a processing unit.

[0023] The processing unit performs:

[0024] The receiving step includes receiving a first control signal for transmitting notification data, a second control signal related to inter-terminal communication, and a data packet containing the data from the base station.

[0025] The demodulation step involves demodulating the data packet according to the first control signal.

[0026] An inter-terminal transmission step, in which, if the data packet is successfully demodulated, a second data packet containing the successfully demodulated data is transmitted to other terminals in radio resources based on the second control signal; and

[0027] The inter-terminal receiving step, in which, in the event that the demodulation of the data packet fails, receives and demodulates the second data packet sent by another terminal in the radio resources based on the second control signal, and uses the data obtained through demodulation as the data contained in the data packet that failed to be demodulated.

[0028] Another aspect of this disclosure is a base station that transmits data to multiple terminals.

[0029] The base station is characterized in that,

[0030] Send a first control signal to the plurality of terminals to notify the transmission of the data, and a second control signal related to inter-terminal communication for receiving / sending the data among the plurality of terminals.

[0031] Data packets containing the data are sent to the plurality of terminals.

[0032] The effects of the invention

[0033] According to this disclosure, even if a terminal has degraded reception quality, it can still receive demodulated data that failed to demodulate from other terminals with good reception. Therefore, it prevents an increase in the transmission power required to restore the specified reception quality for terminals with degraded reception quality or those expected to be degraded. Furthermore, since multiple terminals receiving the same data can each receive demodulated data that failed to demodulate from a successfully demodulated terminal, fewer data packets need to be retransmitted by the base station. These factors contribute to a reduction in base station power consumption. Attached Figure Description Attached Figure Description

[0034] Figure 1 This is a diagram illustrating the configuration of the wireless system involved in the implementation method.

[0035] Figure 2 This is a diagram of the functional blocks of the user terminal and base station involved in the implementation method.

[0036] Figure 3This is a flowchart of the processing performed by the base station in Implementation Method 1.

[0037] Figure 4 This is a flowchart of the processing performed by the user terminal in Implementation Method 1.

[0038] Figure 5 This is a flowchart of the processing performed by the base station in Implementation Method 2.

[0039] Figure 6 This is a flowchart of the processing performed by the user terminal in Implementation Method 4.

[0040] Figure 7 This is a flowchart of the processing performed by the user terminal in Implementation Method 5. Detailed Implementation

[0041] (Implementation Method 1)

[0042] Hereinafter, embodiments of the present disclosure will be described based on the accompanying drawings. The embodiments described below are merely illustrative examples, and the present disclosure is not limited to the configuration of the embodiments. For example, the following description uses cellular communication (mobile communication) utilizing mobile communication, especially 5G standard, but the technology of the present disclosure can also be applied to cellular communication other than 5G standard, or wireless communication other than cellular communication.

[0043] Figure 1 This diagram illustrates the configuration of the wireless communication system according to this embodiment. The system includes multiple user equipment (UE) devices 10 and a base station 20. The user devices 10 are devices with wireless communication capabilities, such as smartphones, tablets, personal computers (PCs), and IoT terminals. The base station 20 is installed, for example, on a satellite or a high-altitude aircraft, to communicate with the user devices 10. Furthermore, the base station 20 may only have the function of a Radio Unit (RU), or it may have the functions of a Distributed Unit (DU) or a Central Unit (CU) in addition to an RU. The base station 20 may also be installed on the ground instead of in the air, such as on a satellite or a high-altitude aircraft.

[0044] Figure 2 The functional block configuration of the user terminal 10 and base station 20 involved in this embodiment is shown.

[0045] The wireless unit 31 performs wireless signal amplification, frequency conversion, extraction of required frequency components, modulation, and demodulation. The data packet demodulation unit 32 demodulates the received data packets, sends successfully demodulated data packets to the data packet decomposition unit, and sends demodulation success information to the wireless protocol control unit 36. The data packet decomposition unit 33 separates the received data and control signals (receive) from the successfully demodulated received data packets. The received data is sent to the upper layer 34 as the communication content, and the control signals are sent to the wireless protocol control unit 36. The transmit data sent from the upper layer 34 and the control signals (transmit) generated by the wireless protocol control unit 36 ​​are assembled into transmit data packets by the data packet assembly unit 35, and then converted into wireless signals by the wireless unit 31 and transmitted. The wireless protocol control unit 36 ​​generates transmission control signals according to standard or predetermined parameters, the success or failure of demodulation of the received data packets, and the control signals in the received data packets, and controls the wireless unit 31 to receive / transmit the specified wireless signals in the specified wireless resources.

[0046] The wireless unit 31, the data packet demodulation unit 32, the data packet decomposition unit 33, the data packet assembly unit 35, and the wireless protocol control unit 36 ​​are each composed of dedicated hardware circuits, but a single circuit may also have multiple functions. Furthermore, any one or all of the aforementioned functional units can be implemented by executing programs through a general-purpose processor.

[0047] also, Figure 2 Even if the functional blocks shown have the same name, their detailed operations may differ in the user terminal 10 and the base station 20. Furthermore, functional blocks related to data packet reception, such as the data packet demodulation unit 32 and the data packet decomposition unit 33, are required in both the base station 20 and the user terminal 10. However, in this embodiment, the transmission from the base station 20 to the user terminal 10 is described, so these are functional blocks required only in the description of the user terminal 10 and not required in the description of the base station 20. Additionally, functional blocks such as the power supply unit and the user interface unit that are not directly necessary for explaining the embodiment of the present invention in either the user terminal 10 or the base station 20 are omitted.

[0048] Figure 3 This is a flowchart illustrating the data transmission processing flow performed by base station 20 in this embodiment. Furthermore, the following... Figure 3 The main body responsible for processing is base station 20, and... Figure 3 It is clear that the related functional units (such as the wireless protocol control unit 36) described below are functional units possessed by the base station 20, so the description of this will be omitted each time.

[0049] In step S101, data to be transmitted to multiple user terminals 10 is generated at the upper layer, and this data is notified to the radio protocol control unit 36, thereby initiating the process. Furthermore, the data transmission to multiple user terminals includes both broadcast and multicast.

[0050] In step S102, the radio protocol control unit 36 ​​determines the radio resources for transmitting data packets containing data. The data packets containing data are transmitted through the downlink data channel (PDSCH), and the radio protocol control unit 36 ​​determines the allocation of frequency resources in units of resource blocks and the scheduling of time resources.

[0051] In step S103, the radio protocol control unit 36 ​​determines the radio resources that enable the terminals to perform inter-terminal communication. Inter-terminal communication is also known as sidelink communication (SL communication), and the frequency and time resources to be used are determined by the base station 20. As described later, the inter-terminal communication in this embodiment is used to retransmit data sent from the base station 20 to the user terminal 10 between terminals 10.

[0052] In step S104, the protocol control unit 36 ​​generates a control signal for sending notification data.

[0053] Additionally, in step S105, the protocol control unit 36 ​​generates a control signal that notifies the availability of wireless resources for inter-terminal communication. The control signal that notifies the transmission of data is equivalent to the first control signal of the present invention, and the control signal that notifies the availability of wireless resources for inter-terminal communication is equivalent to the second control signal of the present invention.

[0054] In step S106, the protocol control unit 36 ​​sends the control signal generated in steps S104 and S105 to the data packet assembly unit 35, which generates a data packet containing the control signal. Alternatively, it is envisioned that a single data packet be generated containing a control signal for notification data transmission and a control signal related to inter-terminal communication, but two separate data packets containing these two control signals can also be generated. These two control signals can be included as physical layer signals in the control signal field set within the data packet. The control signal related to inter-terminal communication can also be included as upper-layer messages in the data field within the data packet. Control information included as physical layer signals in the control signal field within the data packet is sometimes referred to as downlink control information (DCI). Additionally, RRC messages and SIBs (System Information Blocks) are examples of upper-layer messages stored in the data area of ​​the data packet.

[0055] In step S107, the data packet assembly unit 35 receives the transmission data from the upper layer 34 and generates a data packet containing the transmission data. Alternatively, the transmission data from the upper layer 34 can be referred to as user data, and the data packet containing the transmission data can be referred to as a user data packet.

[0056] In step S108, the wireless unit 31 transmits a data packet containing the control information generated in step S106.

[0057] In step S109, the wireless unit 31 transmits a data packet containing the data transmitted in step S107.

[0058] In step S110, the wireless protocol control unit 36 ​​determines whether all the data generated in S101 has been sent. If there is unsent data, it returns to S102 and repeats the above process until all the data is sent.

[0059] Figure 4 This is a flowchart illustrating the data reception processing procedure performed by the user terminal 10 in this embodiment. Furthermore, the following... Figure 4 The main body responsible for processing is user terminal 10, and... Figure 4 It is clear that the related functional units (such as the wireless protocol control unit 36) described below are functional units possessed by the user terminal 10, so the description of this will be omitted each time.

[0060] In step S201, if the user terminal 10 receives a data packet containing control signals from the base station 20 via the radio unit 31, then in step S202, the received data packet is decomposed by the data packet decomposition unit 33 to extract the control signals for transmitting notification data and control signals related to inter-terminal communication. The extracted control signals are then transmitted to the radio protocol control unit 36.

[0061] In step S203, the radio unit 31 receives a data packet containing data transmitted from the base station 20 based on the radio resource information contained in the control signal for transmitting notification data. In step S204, the data packet demodulation unit 32 demodulates the received data packet. The data packet demodulation unit 32 notifies the radio protocol control unit 36 ​​whether the demodulation was successful. In step S205, the radio protocol control unit 36 ​​determines whether the demodulation was successful. If successful, the process proceeds to step S206; if unsuccessful, the process proceeds to step S209.

[0062] If demodulation is successful, in step S206, the radio protocol control unit 36 ​​generates a data packet containing the data demodulated by the data packet assembly unit 35. This data packet is equivalent to the second data packet in this invention. In step S207, the radio protocol control unit 36 ​​controls the radio unit 31 to transmit the generated data packet using the radio resources specified by the control signals related to inter-terminal communication extracted in step S202. Then, in step S208, the radio protocol control unit 36 ​​forwards the demodulated data to the upper layer 34.

[0063] In the event of demodulation failure, in step S209, the radio protocol control unit 36 ​​controls the radio unit 31 to receive data packets in the radio resources specified by the control signals related to inter-terminal communication extracted in step S202. In step S210, the data packet demodulation unit 32 demodulates the data packet (second data packet) received through inter-terminal communication and notifies the radio protocol control unit 36 ​​of whether the demodulation was successful. In step S211, the radio protocol control unit 36 ​​determines whether the demodulation was successful. If successful, the process proceeds to step S208, where the radio protocol control unit 36 ​​forwards the successfully demodulated data to the upper layer 34. That is, the user terminal 10 processes the data received and demodulated through inter-terminal communication as data contained in the data packet received from the base station 20 that failed to be demodulated. On the other hand, in the event of demodulation failure, the process proceeds to step S212, where the radio protocol control unit 36 ​​reports the data reception failure to the upper layer 34. In the event of a reported reception failure, the upper layer 34 can treat the data as lost or request a retransmission. If the failed reception data is part of a data string with error correction codes applied, and if the majority of the remaining data is successfully demodulated, the failed demodulation data can sometimes be recovered by demodulating the error correction codes. Even if there is failed demodulation data in the data packets received from base station 20, the probability of recovery through decoding the error correction codes increases if the data obtained by demodulating the data packets received through inter-terminal communication is supplemented to some extent.

[0064] According to this embodiment, if the user terminal 10 fails to demodulate data from the base station 20, the data can be obtained from another user terminal 10 that has successfully demodulated the data via inter-terminal communication. Since the base station 20 can tolerate demodulation failures in the user terminal 10 to a certain extent, the transmission power can be set to a lower level, and the number of data packets that need to be retransmitted from the base station 20 is reduced. Therefore, both the power consumption and communication resource consumption of the base station 20 can be reduced.

[0065] (Implementation Method 2)

[0066] In Implementation 1, the base station 20 generates and transmits a data packet containing a control signal for transmitting notification data and control signals related to inter-terminal communication each time it transmits a data packet containing data. In this implementation, the base station 20 transmits a data packet containing control signals for transmitting notification data and control signals related to inter-terminal communication before performing a series of transmissions of data packets containing data.

[0067] The configuration of the user terminal 10 and base station 20 in this embodiment is basically the same as that in embodiment 1, with the main difference being the content of data transmission and processing of the base station 20. Hereinafter, descriptions of configurations identical to those in embodiment 1 will be omitted, and the differences between this embodiment and embodiment 1 will be explained.

[0068] Figure 5 This is a flowchart illustrating the data transmission process of base station 20 in this embodiment. Before generating data to be transmitted to the terminal (S305), base station 20 determines radio resources capable of inter-terminal communication and generates and transmits a control signal to notify the radio resources, a data packet containing the control signal, and other related data (S301-S304). Furthermore, the radio resources determined here are identified and notified as radio resources that can be used periodically. Periodic use of radio resources is, for example, defined as SPS (Semi-Persistent Scheduling). The control signal notifying the radio resources can be a physical layer signal or a higher-level message such as an RRC message.

[0069] If base station 20 generates data to be transmitted to the terminal, it performs the following steps (S305 is "Yes"): determining the radio resource for transmitting the data, generating a control signal to notify the radio resource, generating and transmitting a data packet containing the control signal (S306~S307). The radio resource determined here is, in the same manner as described above, a radio resource that is periodically used. The control signal can be a physical layer signal or a higher-level message such as an RRC message.

[0070] Base station 20 also generates a control signal to start the transmission of notification data and sends a data packet containing the control signal (S310~S311). Thereafter, base station 20 repeatedly generates and sends data packets containing data until all data transmission is complete (S312~S314). After all data transmission is complete, base station 20 generates a control signal to end the transmission of notification data and sends a data packet containing the control signal (S315~S316). The control signals for starting and ending the transmission of notification data can be physical layer signals. However, if the content of the transmitted data is broadcast at regular intervals, the transmission of this control signal can be omitted.

[0071] The data reception and processing flow of the user terminal 10 in this embodiment is the same as that in embodiment 1 ( Figure 4 They are basically the same. However, Figure 4 The steps (S301-S302) in the illustrated processing flow, including receiving data packets containing control signals, extracting control signals for sending notification data, and control signals related to inter-terminal communication, only need to be performed once before a series of data packets containing data are received. Furthermore, since control signals for starting and ending the transmission of notification data are added, processing for extracting these control signals and starting and ending the data reception processing based on these control signals is also added.

[0072] In this embodiment, the power consumption of the base station 20 and the communication resource consumption can be reduced in the same way as in the first embodiment.

[0073] (Implementation Method 3)

[0074] In this embodiment, LBT (Listen Before Talk) is applied to the transmission of data packets containing data successfully demodulated by user terminal 10 via inter-terminal communication. The configuration of user terminal 10 and base station 20 in this embodiment is basically the same as in embodiment 1, with the difference being... Figure 4 The flowchart describes step S207 of the process. Hereinafter, descriptions of configurations identical to those in Embodiment 1 will be omitted; instead, the differences from Embodiment 1 will be explained. Furthermore, this embodiment can also be implemented in combination with Embodiment 2.

[0075] Figure 6 This is a flowchart illustrating the transmission process performed via inter-terminal communication in this embodiment. User terminal 10 follows... Figure 4 The flowchart is processed, and through Figure 6 The flowchart shows the process of sending communication between terminals (step S207).

[0076] In this embodiment, the user terminal 10 receives a data packet containing data sent from the base station. If it can be correctly demodulated, it monitors the usage status of radio resources capable of inter-terminal communication, obtained from control signals related to inter-terminal communication (S401). The monitoring time for radio resource usage can follow CSMA-CA (Carrier Sense Multiple Access - Collision Avoidance) or be randomly set according to a corresponding method. Alternatively, if inter-terminal communication is permitted in a frequency band used for cellular wireless communication, autonomous radio resource selection can be performed according to cellular wireless communication standards. A combination of the above methods can also be used.

[0077] User terminal 10 determines whether the wireless resource is idle by monitoring its usage status (S402), and if it determines that the resource is available, it sends a data packet containing data that was successfully demodulated (S403).

[0078] On the other hand, if it is determined that the wireless resources are in use, the user terminal 10 demodulates the data packets (data packets received in S401) sent by other terminals (third terminals) through inter-terminal communication (S404). Based on the demodulation result, the user terminal 10 determines whether the received data packet contains data obtained by demodulating the data packet received from the base station, i.e., whether it contains the same data as the data to be sent through inter-terminal communication (S405). If the same data is contained, the user terminal 10 stops the transmission to be made through inter-terminal communication (S408). If the data packet received through inter-terminal communication does not contain the same data, the user terminal 10 determines whether a predetermined time has elapsed since the data reception (S407). If the predetermined time has not elapsed, it returns to step S401 to monitor the usage status of the wireless resources available for inter-terminal communication. If the data to be sent has not been sent by other user terminals through inter-terminal communication, and a predetermined time has elapsed with no idle wireless resources, the user terminal 10 stops the transmission to be made through inter-terminal communication (S408).

[0079] According to this embodiment, when there are multiple user terminals capable of correctly demodulating data based on data packets received from the base station, conflicts in inter-terminal communication data packets caused by these user terminals simultaneously transmitting inter-terminal communication data can be avoided. Furthermore, since multiple user terminals do not transmit the same data, wireless resources used in inter-terminal communication can be utilized efficiently.

[0080] (Implementation Method 4)

[0081] In this embodiment, the base station 20 sends the control signal for transmitting notification data by attaching an identifier that identifies the data. Alternatively, the identifier can be attached to the data packet containing the data. The data identifier can be included in physical layer signals, such as DCI, and transmitted. This embodiment can be combined with any of embodiments 1 to 3. Hereinafter, an example combining with embodiment 3 will be described, mainly explaining the differences between this embodiment and embodiment 3.

[0082] When the user terminal 10, having correctly demodulated the data packet received from the base station 20 to obtain the data and its identifier, transmits the data packet containing the data and the identifier via inter-terminal communication (S207), it also transmits the data packet containing the data and the identifier. Furthermore, if, before transmission, a data packet sent by another terminal is received and demodulated to obtain the data and its identifier (S404), a determination is made based on the identifier to determine whether the data contained in the data packet sent by the other terminal is the same as the data to be transmitted (S405).

[0083] If a data packet received from base station 20 cannot be correctly demodulated, user terminal 10 can determine the identifier of the data that failed to be demodulated based on the data identifier contained in the control signal for transmitting notification data. Therefore, if the identifier attached to the data packet received in inter-terminal communication matches the identifier attached to the control signal from base station 20, user terminal 10 will forward the data obtained in inter-terminal communication as correctly demodulated data to upper layer 34.

[0084] According to this embodiment, it is possible to easily determine the identity of data (S405).

[0085] (Implementation Method 5)

[0086] In this embodiment, if the demodulation of the data packet sent from the base station fails, the user terminal 10 sends a demodulation failure notification through inter-terminal communication. Upon receiving the demodulation failure notification, the user terminal 10 that successfully demodulates the data packet sends the data packet through inter-terminal communication.

[0087] This embodiment is basically the same as embodiment 1, except that the operation of the user terminal 10 differs from that in embodiment 1. Hereinafter, descriptions of configurations identical to those in embodiment 1 will be omitted; the main focus will be on the differences between this embodiment and embodiment 1. Furthermore, this embodiment can also be implemented in combination with embodiments 2 to 4.

[0088] First, the processing and implementation method 1 from receiving data packets sent by base station 20 to determining whether the data can be correctly demodulated. Figure 4 The steps S201 to S205 are the same. Figure 7This is a flowchart illustrating the processing after step S205 in this embodiment.

[0089] If the data transmitted from the base station can be correctly demodulated (S205 is "Yes"), the user terminal 10 receives data packets in radio resources capable of inter-terminal communication (S501) and determines whether a message indicating data demodulation failure (here, called a demodulation failure notification) has been sent from another user terminal (S502). If a demodulation failure notification is received from another user terminal (S502 is "Yes"), the user terminal 10 generates a data packet containing successfully demodulated data (S503) and transmits the data packet in radio resources capable of inter-terminal communication (S504). Furthermore, this transmission process can also be performed similarly to Embodiment 3, by monitoring the usage status of radio resources capable of inter-terminal communication and determining that no data packet containing the data has been sent from another terminal and that the radio resource is idle. Alternatively, the method of Embodiment 4 can also be used. Regardless of whether a data packet containing successfully demodulated data is transmitted in radio resources capable of inter-terminal communication, the user terminal 10 forwards the successfully demodulated data to the upper layer 34.

[0090] If demodulation of a data packet containing data received from the base station fails (S205 is "No"), the user terminal 10 sends a message indicating demodulation failure (demodulation failure notification) in a radio resource capable of inter-terminal communication (S511). At this time, the usage status of the radio resource capable of inter-terminal communication can also be monitored, and if no data packet containing a demodulation failure message is sent from another terminal, and it is determined that the radio resource is idle, a demodulation failure notification can be sent. Furthermore, if the identifier of the transmitted data is included, the identifier of the demodulated data can also be included in the demodulation failure notification.

[0091] Subsequently, user terminal 10 receives data packets via wireless resources capable of inter-terminal communication (S512) and demodulates the received data packets (S513). If the demodulation of the data packets received through inter-terminal communication is successful (S514 is "Yes"), user terminal 10 forwards the successfully demodulated data to the upper layer (S515); if demodulation fails (S514 is "No"), it reports the data reception failure to the upper layer (S516).

[0092] According to this embodiment, since only the data that failed to demodulate in any one terminal is sent through inter-terminal communication, the transmission processing of user terminals can be reduced, and the consumption of wireless resources can be reduced.

[0093] (Other variations)

[0094] The above-described embodiments are merely an example, and this disclosure can be appropriately modified and implemented without departing from its spirit.

[0095] The above embodiments illustrate an example of cellular communication using the 5G standard (communication via base station and sidelink communication). However, any communication standard can be used as long as it involves wide-area wireless communication via base station or access point, or direct communication between user terminals. Examples of wide-area wireless communication include Wide Area Wireless LAN (IEEE 802.11ah) and WiMax (IEEE 802.6). Examples of direct communication between user terminals include WiFi-Direct and Bluetooth (registered trademark).

[0096] This disclosure can also be implemented by providing a computer with a computer that has the functions described in the above embodiments, and having one or more processors read and execute the program. Such a computer program can be provided to the computer via a non-transitory computer-readable storage medium that can be connected to the computer's system bus, or via a network. Non-transitory computer-readable storage media include, for example, any type of disk such as magnetic disks (floppy disks, hard disk drives (HDDs), etc.), optical disks (CD-ROMs, DVDs, Blu-ray discs, etc.), read-only memory (ROM), random access memory (RAM), EPROM, EEPROM, magnetic cards, flash memory, optical cards, and any type of medium suitable for storing electronic instructions.

[0097] Explanation of reference numerals in the attached figures

[0098] 10: User terminal; 20: Base station

[0099] 31: Wireless Section; 32: Data Packet Demodulation Section; 33: Data Packet Decomposition Section

[0100] 34: Upper layer; 35: Data packet assembly unit; 36: Radio protocol control unit

Claims

1. A wireless communication method, which is a wireless communication method between a base station and a terminal. The wireless communication method includes: In the first sending step, the base station sends a first control signal for sending notification data and a second control signal related to inter-terminal communication to multiple terminals. In the second transmission step, the base station transmits data packets containing the data to the plurality of terminals. The demodulation step involves the terminal demodulating the data packet according to the first control signal. Inter-terminal transmission step, in which, if the data packet is successfully demodulated, the terminal transmits a second data packet containing the successfully demodulated data to other terminals in radio resources based on the second control signal; as well as In the inter-terminal reception step, if the demodulation of the data packet fails, the terminal receives and demodulates the second data packet sent by another terminal in the radio resources based on the second control signal, and uses the data obtained through demodulation as the data contained in the data packet that failed to be demodulated.

2. The wireless communication method according to claim 1, wherein, The inter-terminal transmission step includes: The step of the terminal monitoring the usage status of wireless resources based on the second control signal; and The step of the terminal sending the second data packet when it is able to utilize the wireless resources.

3. The wireless communication method according to claim 2, characterized in that, In the inter-terminal transmission step, if the data is transmitted by a third terminal in the radio resources based on the second control signal, the terminal suspends the transmission of the second data packet.

4. The wireless communication method according to claim 2, characterized in that, In the transmission step, the base station transmits the data by appending an identifier of the data to one or both of the first control signal and the data packet. In the inter-terminal transmission step, the terminal sends the data by appending an identifier to the second data packet, and determines whether the data was sent by another terminal based on the identifier of the data contained in the data packet sent from the other terminal and the identifier of the data appended to the first control signal or the data packet.

5. The wireless communication method according to claim 1, characterized in that, It also includes the step of the terminal, in the event that the demodulation of the data packet fails, sending a demodulation failure notification in radio resources based on the second control signal to indicate that the demodulation of the data packet has failed. In the inter-terminal transmission step, the terminal sends the second data packet in response to receiving the demodulation failure notification from other terminals.

6. The wireless communication method according to claim 1, characterized in that, In the transmission step, the base station transmits the first control signal and the second control signal together in the same data packet.

7. The wireless communication method according to claim 6, characterized in that, The first control signal and the second control signal are data packets as physical layer signals.

8. The wireless communication method according to claim 1, characterized in that, In the transmission step, the base station transmits the first control signal and the second control signal respectively in different data packets.

9. The wireless communication method according to claim 1, characterized in that, At least one of the first control signal and the second control signal notifies the availability of wireless resources that can be periodically utilized.

10. The wireless communication method according to claim 9, characterized in that, At least one of the first control signal and the second control signal is included in the upper-level message.

11. The wireless communication method according to claim 1, characterized in that, In the transmission step, the base station transmits the first control signal, the second control signal, and the data packet to multiple terminals via broadcast or multicast.

12. The wireless communication method according to claim 1, characterized in that, The base station is composed of artificial satellites or aircraft.

13. A user terminal, comprising a processing unit, The processing unit performs: The receiving step includes receiving a first control signal for transmitting notification data, a second control signal related to inter-terminal communication, and a data packet containing the data from the base station. The demodulation step involves demodulating the data packet according to the first control signal. Inter-terminal transmission step, in which, if the data packet is successfully demodulated, a second data packet containing the data of successful demodulation is transmitted to other terminals in radio resources based on the second control signal; as well as The inter-terminal receiving step, in which, in the event that the demodulation of the data packet fails, receives and demodulates the second data packet sent by another terminal in the radio resources based on the second control signal, and uses the data obtained through demodulation as the data contained in the data packet that failed to be demodulated.

14. The user terminal according to claim 13, wherein, The inter-terminal transmission step includes: The step of monitoring the usage of wireless resources based on the second control signal; and The step of sending the second data packet when the wireless resources are idle and no other terminal is transmitting the data.

15. The user terminal according to claim 14, characterized in that, In the inter-terminal transmission step, if the data transmission has been performed in the radio resources based on the second control signal, the transmission of the second data packet is suspended.

16. The user terminal according to claim 14, characterized in that, The identifier of the data is appended to the first control signal or the data packet. In the inter-terminal transmission step, the identifier of the data is appended to the second data packet and transmitted. Furthermore, a determination is made as to whether the data was transmitted by another terminal based on the identifier of the data contained in the data packet transmitted from the other terminal and the identifier of the data appended to the first control signal or the data packet.

17. The user terminal according to any one of claims 13 to 16, characterized in that, The processing unit further performs the step of: in the event that the demodulation of the data packet fails, sending a demodulation failure notification in radio resources based on the second control signal to indicate that the demodulation of the data packet has failed. In the inter-terminal transmission step, in response to receiving the demodulation failure notification from another terminal, the second data packet is transmitted.

18. The user terminal according to claim 17, characterized in that, An identifier for the data is appended to the first control signal. In the event of a data packet demodulation failure, the processing unit includes the identifier of the data corresponding to the failed data packet in the demodulation failure notification. Based on the data identifier, it determines whether the data obtained by receiving and demodulating the second data packet sent by another terminal in the radio resources based on the second control signal is data that failed to demodulate. In the inter-terminal transmission step, in response to receiving a demodulation failure notification containing an identifier of the data from another terminal, the data corresponding to the identifier of the data is included in the second data packet and transmitted.

19. The user terminal according to claim 13, characterized in that, The first control signal and the second control signal are data packets as physical layer signals.

20. The user terminal according to claim 13, characterized in that, At least one of the first control signal and the second control signal is a control signal that notifies the availability of radio resources that can be periodically utilized, and is included in the upper-level message.

21. A base station that transmits data to multiple terminals, The base station is characterized in that, Send a first control signal to the plurality of terminals to notify the transmission of the data, and a second control signal related to inter-terminal communication for receiving / sending the data among the plurality of terminals. Data packets containing the data are sent to the plurality of terminals.

22. The base station according to claim 20, characterized in that, The data packet is sent with the identifier of the data appended to it.

23. The base station according to claim 21, characterized in that, The first control signal and the second control signal are data packets as physical layer signals.

24. The base station according to claim 21, characterized in that, At least one of the first control signal and the second control signal is a control signal that notifies the availability of radio resources that can be periodically utilized, and is included in the upper-level message.

25. The base station according to claim 21, characterized in that, The base station is mounted on a satellite or spacecraft.

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