JP2020150374A - Control device, terminal device, control method, communication method, and program for performing parameter setting for repetitive transmission - Google Patents

Abstract

To prevent the occurrence or influence of interference.SOLUTION: A control device notifies a terminal device which repetitively transmits one piece of data using a radio resource allocated in advance of at least two sets of parameters to be used for the repetitive transmission. The terminal device performs repetitive transmission using one of the at least two sets according to the notification.SELECTED DRAWING: Figure 9

Description

The present invention relates to a parameter setting technique for repeatedly transmitting one piece of data.

The 3GPP (3rd Generation Partnership Project) has established standards for 5th generation (5G) cellular communication systems. In this standard, in addition to the mechanism by which the terminal device (UE) transmits a signal using the radio resource (frequency / time resource) allocated by transmitting the scheduling request, the radio resource allocated in advance is used. A mechanism for transmitting a signal without transmitting a scheduling request (Configured grant) is defined (see Non-Patent Document 1).

3GPP, TS38.331, V15.3.0, September 2018

The 3GPP also defines a method for repeatedly transmitting one piece of data in order to expand the coverage area and the like. If repetitive transmission is used when radio resources are pre-allocated to the UE by the configured grant as described above, interference may occur due to other UEs also transmitting signals with the radio resources used for repetitive transmission. .. Further, in response to such interference, the base station, which is a receiving device, can perform signal processing to separate a plurality of signals, but an increase in computing resources for signal processing at that time can be a problem.

The present invention provides a technique for suppressing the occurrence or influence of interference.

The control device in one embodiment of the present invention is a terminal device that repeatedly transmits one data using a pre-allocated radio resource, and is at least two sets of parameters to be used for the repeated transmission. The terminal device has a notification means for notifying the at least two sets, indicating that the repetitive transmission should be performed using one of the at least two sets.

A terminal device according to an aspect of the present invention comprises a receiving means that receives from a control device at least two sets of parameters that should be used to repeatedly transmit a piece of data using pre-allocated radio resources. It has an execution means for performing the repetitive transmission using at least one of two sets.

According to the present invention, the occurrence or influence of interference can be suppressed.

It is a figure which shows the configuration example of a wireless communication system. It is a figure explaining the example of the parameter setting of repeated transmission. It is a figure explaining the example of the parameter setting of repeated transmission. It is a figure which shows the example of the table which defined the parameter. It is a figure which shows the hardware configuration example of a control device and a terminal device. It is a figure which shows the functional configuration example of a control device. It is a figure which shows the functional configuration example of a terminal device. It is a figure which shows the example of the flow of processing executed in a wireless communication system. It is a figure which shows the example of the flow of processing executed in a wireless communication system.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the plurality of features described in the embodiments may be arbitrarily combined. In addition, the same or similar configuration will be given the same reference number, and duplicate description will be omitted.

(System configuration)
FIG. 1 shows a configuration example of the wireless communication system according to the present embodiment. In one example, the wireless communication system according to the present embodiment includes a base station 101 and terminal devices 102 to 104 capable of connecting to and communicating with the base station 101. The number of base stations may be two or more, and the number of terminal devices may be two or less or four or more. In one example, the base station 101 allocates a radio resource for transmitting an uplink signal (for example, a physical uplink shared channel, PUSCH) to the terminal device 102 and the terminal device 103 in advance. When there is data to be transmitted on the uplink, the terminal device 102 and the terminal device 103 send a signal (for example, PUSCH) using the pre-allocated radio resource without transmitting a scheduling request to the base station 101. Can be sent. Such pre-allocation of radio resources is called a configured grant. On the other hand, it is assumed that the terminal device 104 is not assigned a radio resource in advance. When the data to be transmitted is generated, the terminal device 104 can transmit a scheduling request to the base station 101 and transmit the data using the radio resources allocated accordingly. Further, the wireless communication system includes a control device 111 that controls communication, and the control device 111 controls communication between the base station 101 and the terminal device 102 to the terminal device 104. In the present embodiment, when the control device 111 exists inside the base station 101 and it is not necessary to distinguish between them, the base station 101 will be described as executing the processing of the control device 111. The 111 may be a device existing outside the base station 101, for example, a network node in the core network.

The terminal device 102 to the terminal device 104 can repeatedly transmit one data (user data, control data) a plurality of times. It should be noted that the repeated transmission of one data here means that a signal for obtaining one data as a decoding result is transmitted a plurality of times, and does not necessarily mean that the same signal is transmitted a plurality of times. .. For example, as a result of encoding one data, a plurality of signals corresponding to a plurality of redundancy versions can be generated, and the plurality of signals can be sequentially transmitted. The gain obtained by such repeated transmission can improve the communication quality and expand the coverage area. The terminal devices 102 to 104 provide parameters from the base station 101 including the number of repeated transmissions, the redundancy version at the time of repeated transmissions, the cycle of resource positions including repeated transmissions, and other information necessary for uplink transmissions. Obtained by the signal of. This signal is transmitted from the base station 101 to the terminal device by RRC (radio resource control) signaling.

In one example, the terminal device 104 may receive the above-mentioned parameters as information included in the RRC message transmitted from the base station 101 in response to the transmission of the scheduling request. The terminal device 104 uses this parameter to transmit an uplink signal. On the other hand, the terminal device 102 and the terminal device 103 use the above-mentioned parameters and radio resources (frequency / time) available for data transmission via the RRC message from the base station 101 before the transmission target data is generated. Can receive allocation settings for resources). As a result, the terminal device 102 and the terminal device 103 transition to the state in which the configured grant setting is made. Then, the terminal device 102 and the terminal device 103 can transmit the uplink signal by using the radio resource allocated in advance.

Pre-allocation of radio resources may allow the same radio resource to be used by multiple terminals. That is, since it is unpredictable whether or not transmission target data is generated in the terminal device, it is possible to allocate overlapping wireless resources to a plurality of terminal devices from the viewpoint of effective use of wireless resources. At this time, when a plurality of terminal devices transmit signals using the overlapping radio resources, the signals interfere with each other and the base station fails to receive the signals, or because of the separation of the signals. It may be necessary to perform complex processing.

Therefore, the base station 101 (control device 111) of the present embodiment preallocates the radio resource, and when the repetitive transmission can be executed by the preallocated radio resource, the influence of the interference due to the repetitive transmission is reduced. Set additional parameters to do so. Therefore, the base station 101 is assigned a terminal device to which the radio resource is allocated in advance with a parameter including a setting element not included in the parameter set for the terminal device 104 to which the radio resource is allocated according to the scheduling request. Notify 102 and the terminal device 103. The terminal device 102 and the terminal device 103 repeatedly execute transmission according to the received parameters with the radio resources allocated in advance. The base station 101 separately sets the parameters to be notified to the terminal device 102 and the parameters to be notified to the terminal device 103. That is, unique parameters are set for the terminal device 102 and the terminal device 103. In one example, different parameters are set for each of the plurality of terminal devices so that the effects of interference can be kept sufficiently low even if the signals from these devices are transmitted using the same radio resource. To.

Additional configuration elements include, for example, specifying the time interval between at least two transmissions in a series of repetitive transmissions. That is, for example, when the number of repetitions is two, the signal corresponding to one data is transmitted twice, and the interval between the first and second of the two transmissions is an additional setting element. Can be notified as. For example, even if the first transmission timings of two or more terminal devices match, the second transmission timings can be shifted by setting different time intervals for each of the two or more terminal devices. Can be done. As a result, the influence of interference can be reduced.

Also, additional configuration elements include the designation of at least two frequency resources to be used in each of at least two transmissions in a series of iterative transmissions. That is, instead of continuing to use the same frequency during repeated transmissions, at least one of the repeatedly transmitted signals is distributed on a different frequency resource than the first transmitted signal, i.e. on the frequency axis. Will be sent. By such distributed transmission on the frequency axis, the probability that the signals transmitted by the two terminal devices interfere with each other can be reduced.

Here, an example of the time interval and the distributed arrangement of the signals transmitted in a series of repeated transmissions on the frequency axis will be described with reference to FIG. Two types of settings are shown in FIG. Setting 1 in FIG. 2 shows an example of a setting in which the number of repetitions is 4 and the signal corresponding to one data is transmitted 5 times in addition to the signal transmitted for the first time. The number of repetitions is an element that is set regardless of whether or not the radio resource is allocated in advance. In setting 1, the time interval and frequency hopping, which are additional setting elements, are set to 1, respectively. The time interval is an element indicating how much time interval is left between the timing at which one signal is transmitted and the timing at which the next signal is transmitted in a series of repeated transmissions. When the time interval is set to "n", the terminal device is set to transmit the next signal after waiting a time corresponding to n signals after one signal is transmitted. Further, the frequency hopping here indicates the number of times the frequency shift is repeated. That is, when frequency hopping is set to the number "m-1" of 1 or more, in a series of repeated transmissions, after one signal is transmitted, the next signal is transmitted using adjacent frequency resources. Will be done. Then, the same thing was done m-1 times, and after the mth signal was transmitted at the position farthest from the signal transmitted for the first time on the frequency axis, the m + 1th signal was transmitted for the first time. It is transmitted at the same frequency as the signal. The frequency of the m + 2nd and subsequent signals is also shifted in the same manner, and the 2m and 3m signals are transmitted at the position farthest from the first transmitted signal on the frequency axis, and the 2m + 1st and 3m + 1 signals are transmitted. The eye, ... signal is transmitted at the same frequency as the first transmitted signal. In setting 1 of FIG. 2, since the frequency hopping is set to "1", m = 2, and the first, third, and fifth signals are transmitted at the same frequency, and the second and second signals are transmitted. The fourth signal is transmitted at a frequency different from these.

Setting 2 of FIG. 2 also includes similar additional setting elements, but here the time interval is set to "0" and the frequency hopping is set to "2". Since the time interval is "0", there is no gap between the signals in a series of repeated transmissions. Therefore, the target signal for repeated transmission is transmitted continuously in time. On the other hand, the frequency hopping is "2". Therefore, the first, fourth, and seventh signals are transmitted at the same frequency, and the second, fifth, and eighth signals are transmitted at different frequencies. Furthermore, the 3rd, 6th, and 9th signals have different frequencies from the 1st, 4th, and 7th signals as well as the 2nd, 5th, and 8th signals. Is transmitted using.

In setting 1 and setting 2 of FIG. 2, the radio resources used at the time of the first transmission are the same, and the transmission is performed for the same time length, but the signals transmitted from the second time onward do not interfere with each other. In this way, the influence of interference can be reduced by distributing the radio resources used for repetitive transmission in the time and frequency domains. The above setting is only an example, and "time interval" and "frequency hopping" may not be used. That is, the setting element may be defined in any format as long as the transmitted signal can be transmitted in a distributed manner in at least one of the time direction and the frequency direction. In one example, a plurality of time / frequency hopping patterns may be prepared in advance, and the base station may notify each terminal device which of them is to be used.

Also, additional configuration elements may include specifying precoding settings for each of at least two transmissions in a series of repetitive transmissions. The "precoding" here is to multiply the signals transmitted from each of the plurality of antenna elements by an appropriate weighting coefficient in order to obtain a predetermined directivity. According to this setting element, the directions in which the signals are transmitted are spatially dispersed, so that, for example, in the base station, the directions in which the signals arrive at a predetermined intensity or higher are dispersed. As a result, even when two or more terminal devices transmit signals at the same time, the signals transmitted at any transmission opportunity in repeated transmission arrive at the base station in a spatially separable state. can do. As a result, the influence of interference can be reduced. Further, by such precoding, the terminal device can distribute and transmit a plurality of signals in repeated transmission to two or more base stations. In this case, the signals received by each base station can be aggregated into, for example, one base station or network node to obtain the gain of repeated transmission. Then, even when signals are transmitted to a plurality of base stations and sufficient spatial separation capability is not prepared on the base station side, or when a plurality of paths reachable to the base station cannot be set. , The influence of interference can be reduced.

Further, the additional setting element may include a setting for specifying a NOMA (Non-Orthogonal Multiple Access) identifier used in each of at least two transmissions in a series of repeated transmissions. The NOMA identifier is a signature used to separate the plurality of signals, for example, when the base station receives the plurality of signals at the same time. The two signatures are generated so that the cross-correlation is zero or sufficiently small. This makes it possible to separate two signals that interfere with each other. On the other hand, when two terminal devices transmit signals using the same NOMA identifier, it is difficult to separate the signals from these terminal devices. On the other hand, including the NOMA identifier as an additional setting element, one of the terminal devices makes the NOMA identifier at the time of the first transmission different from the NOMA identifier at least in at least one of the second and subsequent transmissions, for example. Therefore, it is possible to reduce the probability that a situation in which signal separation is difficult occurs.

Also, additional configuration elements include specifying the transmission port of the demodulation reference signal (DMRS) used in each of at least two transmissions in a series of repeated transmissions. Further, an additional setting element includes a specification of a DMRS configuration type used in each of at least two transmissions in a series of repeated transmissions. Also, additional configuration elements include the designation of additional DMRS to be used in each of at least two transmissions in a series of repetitive transmissions. Further, the additional setting element includes the specification of the number of symbols of the additional DMRS used in each of at least two transmissions in the series of repeated transmissions. These additional settings for DMRS can reduce the effects of interference by eliminating the use of the same DMRS settings for all signals when at least two terminals repeatedly transmit. As an example, FIG. 3 shows an example of setting the transmission port of DMRS. In the example of FIG. 3, an example is shown in which the two ports are used by switching between the odd-numbered (first, third, fifth ...) transmission and the even-numbered (second, fourth, sixth) transmission. ing. By switching the port, the mapping of DMRS to frequency / time resources is switched. In this way, when the terminal device switches the use of a plurality of ports to transmit DMRS, for example, when another terminal device transmits DMRS using the same port, two signals are used in half of the signals in repeated transmission. It is possible to prevent the DMRSs of the signals from overlapping. As a result, for example, by improving the accuracy of channel estimation, the separation of a plurality of signals can be improved with high accuracy, and the influence of interference can be reduced. Similarly, in other settings, the influence of interference can be reduced by making settings so that DMRSs do not overlap between the two signals.

Further, an additional setting element includes a specification as to whether or not to use a phase tracking reference signal for each of at least two transmissions in a series of repeated transmissions. Also, additional configuration elements include specifying the density at which the phase tracking reference signal is placed at each of at least two transmissions in a series of iterative transmissions. By using the phase tracking reference signal, it is possible to track the phase (on the IQ plane) of the signal of the terminal device moving at high speed. When such a phase tracking reference signal is used, it is necessary to reduce the influence of interference that the phase tracking reference signal receives from other signals. For this reason, for example, when the number of repetitions is small and the dispersion of interference is expected to be insufficient, interference can be achieved by performing predetermined processing such as increasing the density of the phase tracking reference signal. It is possible to reduce the influence of. Further, for example, in an environment where interference with DMRS occurs, a setting may be made such that a phase tracking reference signal is used to reduce the influence of the interference.

Information for specifying the above-mentioned additional setting elements is prepared as a table common to the base station and the terminal device, and the base station specifies to the terminal device one combination included in the table. May be notified as information on the settings to be used. An example of this table is shown in FIG. As shown in FIG. 4, the table defines settings such as time interval, frequency position, and the like for each index, and information specifying the index in the table is transmitted from the base station to the terminal device. The terminal device can specify the setting of repeated transmission according to the received index. The format shown in FIG. 4 is only an example, and a table of any format may be used as long as the settings can be specified. For example, FIG. 4 shows a table for additional configuration elements, but the table may also include basic parameters for iterative transmission that are also used in terminal devices where Configured grant is not used. Good. In addition, a table for each of the terminal device in which the configured grant is used and the terminal device in which the configured grant is not used may be prepared separately.

Further, the above-mentioned additional setting elements may be provided from the base station to the terminal device during RRC signaling, or may be provided, for example, by the downlink control information (DCI) of the physical downlink control channel (PDCCH). Good. In this case, during RRC signaling, the terminal device is notified of common settings (for example, the number of repeated transmissions, the redundancy version at the time of repeated transmissions, the cycle of resource positions including repeated transmissions, etc.) regardless of whether Configured grant is used or not. Later, additional configuration elements may be specified by DCI or the like for the terminal device for which the Configured grant is used.

The control device may notify the terminal device of two or more combinations of parameters. That is, in one example, the control device notifies the terminal device 102 and the terminal device 103 in which the configured grant is used of a plurality of sets of parameters including additional setting elements, and notifies the terminal device 104 in which the configured grant is not used. On the other hand, it is possible to notify a plurality of sets of parameters that do not include additional setting elements. In addition, the control device may notify two or more sets of parameters only to the terminal device in which the configured grant is used. For example, the control device can notify the terminal device of two or more indexes using the table as described above. The notification of this parameter can be notified from the control device (base station) to the terminal device by, for example, RRC signaling or PDCCH. When the terminal device receives two or more sets of parameters, the terminal device can repeatedly perform transmission with preset radio resources using one of the two or more sets.

The control device also specifies, for example, a first set of parameters that the terminal device should initially use. In this case, the terminal device may repeatedly perform transmission with preset radio resources using the first set unless otherwise instructed by the control device. The control device does not have to instruct the terminal device to use the first set. In this case, the terminal device may transmit, for example, a signal transmitted on the uplink including information indicating a set of parameters to be used. This allows the base station to recognize which set the terminal device is using to transmit the uplink signal. When the base station specifies a set of parameters to be used by the terminal device, the terminal device does not need to notify the base station of information indicating the set of parameters to be used.

The controller may also instruct the terminal device to change the set of parameters used. The terminal device may change the first set of parameters currently in use to a second set different from the first set according to this instruction. The terminal device can then perform repetitive transmissions with a second set of modified parameters. The control device may or may not specify the second set to be used after the change when giving the above instruction. If the second set is not specified, the terminal device may transmit, for example, after changing the set of parameters to be used, including information indicating the changed set of parameters in the uplink signal. As a result, the base station can recognize which set of parameters used by the terminal device is used. When the second set is specified, the terminal device does not need to notify the base station of the information indicating the changed parameter set.

The instruction to change the set of parameters to be used can be transmitted using PDCCH. In one example, the controller notifies the terminal device of information specifying at least two sets of parameters and a set of parameters to be used initially by means of an RRC message. The controller then uses the PDCCH to instruct the terminal device to change the set of parameters to be used by DCI. The instruction to change the set of parameters to be used may be transmitted by using an RRC message. For example, an RRC Connection Reconfiguration message sends an instruction to change the set of parameters to be used to the terminal device.

A parameter to be used by the control device, for example, when the probability of failure in communication with a certain terminal device exceeds a predetermined value, or when the wireless quality of the signal from the terminal device cannot be sufficiently ensured. The change instruction of the set can be transmitted to the terminal device. Further, the control device may transmit an instruction to change the set of parameters to be used to the terminal device, for example, depending on the usage status of the radio resource. For example, the controller may send instructions to the terminal device to use a set of parameters with a low number of iterations when the radio resource utilization is high. Further, when the usage rate of a predetermined frequency resource among the radio resources is high, the control device can instruct the terminal device to change to a set of parameters that do not use the frequency resource. It should be noted that these are only examples, and the control device may issue an instruction to change the set of parameters to be used for various reasons. Further, the terminal device may transmit a request for changing the set of parameters to be used to the control device because the probability of failure of the uplink signal transmission exceeds a predetermined value or the like. In response to this change request, the control device may transmit a change instruction of a set of parameters to be used in the terminal device to the terminal device. Further, in response to this change request, the control device transmits, for example, a change instruction of a set of parameters to be used to another terminal device that is presumed to interfere with the communication of the terminal device. May be good. The change request from the terminal device may be transmitted on the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH) in one example. The control device may instruct the terminal device to interrupt the repeated transmission. Further, the terminal device may request the control device to interrupt the repeated transmission.

Further, the terminal device may continue to use the set of one or more parameters set via one base station in the communication with another base station after the handover as described above. Good. In this case, the set of parameters used in the communication with the base station before the handover is notified to the base station after the handover. This notification is performed, for example, by a control device outside the base station or a base station before the handover thereof transmits information for specifying a set of parameters to the base station after the handover. After the handover, the base station can use this notification to receive the uplink signal repeatedly transmitted from the terminal device.

Subsequently, an example of the configuration and processing flow of the control device (base station) and the terminal device that execute the above-described processing will be described.

(Device configuration)
FIG. 5 shows an example of hardware configuration of the control device and the terminal device according to the present embodiment. The control device and the terminal device include, in one example, a processor 501, a ROM 502, a RAM 503, a storage device 504, and a communication circuit 505. The processor 501 is a computer including one or more processing circuits such as a general-purpose CPU (central processing unit) and an ASIC (integrated circuit for a specific application), and is stored in a ROM 502 or a storage device 504. By reading and executing the program, the entire processing of the device and each of the above-mentioned processing are executed. The ROM 502 is a read-only memory that stores information such as programs and various parameters related to processing executed by the apparatus. The RAM 503 is a random access memory that functions as a workspace when the processor 501 executes a program and stores temporary information. The storage device 504 is composed of, for example, a detachable external storage device or the like. The communication circuit 505 is composed of, for example, a circuit for wired communication or wireless communication. When the control device is included in the base station device, for example, it has a communication circuit for connecting to other functional units in the base station device, and when it is included in a network node outside the base station device. Has a wired communication circuit for communicating with the base station device. The control device can communicate with the terminal device via a wireless communication circuit included in the base station device. Further, the terminal device has a wireless communication circuit for communicating with the base station device. Although one communication circuit 505 is shown in FIG. 5, the control device and the terminal device may have a plurality of communication circuits. For example, the terminal device may further have a communication circuit for communication by wireless LAN, Bluetooth (registered trademark), or the like.

FIG. 6 shows an example of the functional configuration of the control device. In one example, the control device includes a communication control unit 601, a table holding unit 602, a setting notification unit 603, and a setting change instruction unit 604. The communication control unit 601 controls communication with the terminal device. For example, when the control device is included in the base station, the communication control unit 601 establishes a wireless link with the terminal device and performs wireless communication. Further, when the control device is not included in the base station, the communication control unit 601 establishes a communication link with the terminal device via the base station and performs communication. The table holding unit 602 holds a table in which an index is associated with a parameter related to repeated transmission including at least an additional setting element, as shown in FIG. 4, for example. When the table is not used, the control device may not include the table holding unit 602. The setting notification unit 603 notifies the terminal device of the parameters related to the repeated transmission via the communication control unit 601. The setting notification unit 603 includes additional setting elements as parameters to be notified to the terminal device using the configured grant, which are not included in the basic parameters notified to the terminal device not using the configured grant. However, it can notify the parameters. The additional setting element may be notified by, for example, an RRC message together with the basic parameters, or may be notified by, for example, PDCCH (DCI) or the like separately from the basic parameters. Since the details of the additional setting elements are as described above, the description thereof will be omitted here. The setting notification unit 603 may notify one terminal device of a plurality of parameter sets. The setting change instruction unit 604 notifies the terminal device of a plurality of sets of parameters by the setting notification unit 603, and when the terminal device determines that the setting needs to be changed, the terminal device Send a setting change instruction to. At this time, the setting change instruction unit 604 may or may not transmit the information for specifying the changed parameter set to the terminal device, or may not transmit such information. In one example, the setting change instruction is transmitted by an RRC message or PDCCH (DCI). The setting change instruction unit 604 may transmit the setting change instruction when receiving the setting change request from the terminal device.

FIG. 7 shows an example of the functional configuration of the terminal device. In one example, the terminal device includes a communication control unit 701, a setting receiving unit 702, a table holding unit 703, a change instruction receiving unit 704, and a communication setting unit 705. The communication control unit 701 controls communication with the base station (and control device). For example, the communication control unit 701 establishes a wireless link with the base station and performs wireless communication. The setting receiving unit 702 receives the setting information from the control device via the communication control unit 701. When using the configured grant, the terminal device can receive a parameter including additional setting elements that are not included in the basic parameters notified to the terminal device that does not use the configured grant. At this time, additional configuration elements may be received with or separately from the basic parameters. The table holding unit 703 holds a table common to the table held by the table holding unit 602, or a table corresponding to a part of the table held by the table holding unit 602. When the table holding unit 703 holds only a table corresponding to a part of the table held by the table holding unit 602, the control device holds this table by the table holding unit 602. You are aware of which part of the table it corresponds to. Then, the control device can notify the terminal device of information specifying which index of the table held by the table holding unit 703 is to be used. If the table is not used, the table holding unit 703 may be omitted. The change instruction receiving unit 704 receives a setting change instruction from the control device.

The communication setting unit 705 sets the communication of the communication control unit 701 based on the information received by the setting receiving unit 702 or the setting change instruction received by the change instruction receiving unit 704. In the present embodiment, the communication setting unit 705 sets the communication control unit 701 using the above-mentioned basic parameters and additional setting elements, for example, when the configured grant is used and the transmission is repeated. I do. On the other hand, the communication setting unit 705 uses the basic parameters without using the above-mentioned additional setting elements when the transmission is repeatedly performed in a situation where the configured grant is not used, for example, the communication control unit 701. Set. When the setting receiving unit 702 has received a plurality of parameter sets, the communication setting unit 705 sets the communication control unit 701 using one of the plurality of sets. The set to be used initially may be notified from the control device, for example. Note that this notification may be an explicit notification, for example, when multiple sets of notifications are made using a series of indexes, the set corresponding to the first index of the series is initially used. An implied notice may be given, such as being recognized as a set to be made. Further, the communication setting unit 705 changes the set of parameters used up to that point to another set of parameters in response to the reception of the change instruction of the set of parameters to be used by the change instruction receiving unit 704. I do. The changed set may be explicitly notified by the control device or may be implicitly notified. For example, if multiple sets of notifications are made using a series of indexes, the next index of the index corresponding to the currently used set of the series is specified, and the set corresponding to the specified index is specified. It can be specified as a set to be used after changing the settings. Further, the communication setting unit 705 may autonomously select the changed parameter set when the control device does not specify the changed parameter set.

(Processing flow)
Subsequently, the flow of processing executed by the wireless communication system of the present embodiment will be outlined with reference to FIG. Note that the process of FIG. 8 is illustrated by focusing on the communication between the base station and the terminal device. That is, when the control device is not included in the base station, the setting information is transmitted from the control device to the base station, and the setting information is transferred to the terminal device. Here, between the control device and the base station. Communication is omitted for the sake of simplicity. In the process of FIG. 8, first, the base station notifies the terminal device of information indicating the pre-allocation setting of the radio resource and the setting at the time of repeated transmission by the RRC message (S801). Here, since the terminal device receives the pre-allocation of the radio resource (that is, the configured grant is used), the parameter including the above-mentioned additional setting element is notified to the terminal device. In this example, the RRC message notifies the additional setting element, but the present invention is not limited to this. For example, additional configuration elements may be notified by a DCI subsequently transmitted by the PDCCH to the terminal device. When additional setting elements are transmitted using the RRC message, the setting information is collectively notified to the terminal device, so that the setting information can be efficiently notified to the terminal device. On the other hand, when an additional setting element is transmitted separately from the RRC message, the additional setting element is adaptively changed according to the situation of the terminal device and the situation of other terminal devices in the wireless communication system. Can be done. In one example, the base station may transmit additional configuration elements in an RRC message and then, if necessary, transmit updated additional configuration element information via PDCCH. The terminal device transitions to the state in which the radio resource is set in advance (Configured grant state) by the message of S801 (S802). After that, when transmission target data (user data or control data) is generated in the terminal device (S803), the terminal device transmits the data using the setting information notified in S801 (S804).

As described above, in the present embodiment, when the configured grant is used, the communication setting using the additional setting element is executed for the terminal device which repeatedly executes the transmission, and when the configured grant is not used. Is executed without any additional setting elements. As a result, it is possible to reduce the probability of occurrence of interference when repeated transmission is executed with the radio resource allocated in advance, or to reduce the influence thereof.

Subsequently, an example of the flow of the process of changing the set of parameters used in the terminal device will be described with reference to FIG. In FIG. 9, it is assumed that a plurality of sets of parameters are notified to the terminal device by the process as shown in FIG. In this process, it is assumed that the terminal device is initially set to use the first set of parameters among the plurality of sets of parameters. The set to be used initially can be specified by the base station (control device), for example, in S801 of FIG. 8 or when the parameter set is separately notified by PDCCH or the like. When transmission target data (user data or control data) is generated in this state (S901), the terminal device repeatedly transmits the data using the first set of parameters (S902). After that, the base station transmits an instruction to change the set of parameters to be used to the terminal device (S904). The base station may transmit this change instruction in response to receiving, for example, a request to change the set of parameters from the terminal device (S903). It is not necessary to request to change this set of parameters. That is, the base station can decide to change the set of parameters that the terminal device should use according to the reason such as communication quality and radio resources, without the request from the terminal device. Here, the instruction to change the set of parameters is transmitted from the base station to the terminal device using, for example, an RRC message or PDCCH (DCI). Further, the request for changing the set of parameters may be transmitted by PUCCH or PUSCH. The terminal device then changes the set of parameters to use according to the instructions for changing the set of parameters. Here, the changed set of parameters is set as the second set of parameters. The terminal device transmits the subsequent signal transmission according to the second set of parameters in response to completing the change of the set of parameters to be used. The terminal device may change the set of parameters during the series of repeated transmissions related to one data, or may change the set of parameters after the series of repeated transmissions related to one data is completed. Good.

By notifying the terminal device in advance of a plurality of sets of parameters in this way and enabling switching between the set of parameters to be used among the plurality of sets, the influence of interference can be further reduced. .. For example, if there are two terminals using a set of parameters that are similar to each other, these terminals can be modified by changing the set of parameters used by one of the two terminals. It is possible to prevent the signals transmitted by the device from interfering with each other, or to suppress the influence of the interference.

The invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the gist of the invention.

Claims (15)

For a terminal device that repeatedly transmits one data using a pre-allocated radio resource, at least two sets of parameters that should be used for the repeated transmission, said at least two of the terminal devices. A control device comprising a notification means for notifying at least two sets indicating that one of the sets should be used to perform the repetitive transmission. 1. The first aspect of the present invention is characterized in that the terminal device further includes an instruction means for instructing the terminal device to change the set of parameters used for the repeated transmission to another set. The control device described. The control device according to claim 2, wherein the instruction means transmits the instruction by using a physical downlink control channel (PDCCH). The control device according to claim 2, wherein the instruction means transmits the instruction by using a radio resource control (RRC) message. The control device according to any one of claims 2 to 4, wherein the instruction means transmits the instruction in response to a request from the terminal device. A receiving means that receives from the controller at least two sets of parameters that should be used to iteratively transmit a piece of data using pre-allocated radio resources.
An execution means for executing the repetitive transmission using one of the at least two sets, and
A terminal device characterized by having. When the repetitive transmission is performed by using the first set of the two sets, the executing means sets the parameters used for the repetitive transmission to another set of the first set. The claim is characterized in that the repetitive transmission is performed using the second set of the two sets in response to the receiving means receiving the instruction to change to the control device. Item 6. The terminal device according to item 6. The terminal device according to claim 7, wherein the instruction is transmitted using a physical downlink control channel (PDCCH). The terminal device according to claim 7, wherein the instruction is transmitted using a radio resource control (RRC) message. The control device further comprises a transmission means for transmitting a request to change the parameters used for the repetitive transmission.
The terminal device according to any one of claims 7 to 9, wherein the instruction is transmitted from the control device in response to the request. The terminal device according to claim 10, wherein the transmission means transmits the request using a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). A control method performed by a controller,
For a terminal device that repeatedly transmits one data using a pre-allocated radio resource, at least two sets of parameters that should be used for the repeated transmission, and the terminal device is the at least two. A control method comprising a notification step notifying at least two sets indicating that one of the sets should be used to perform the repetitive transmission. A communication method executed by a terminal device
A receiving process that receives from the controller at least two sets of parameters that should be used to iteratively transmit a piece of data using pre-allocated radio resources.
An execution step of executing the repetitive transmission using one of the at least two sets, and
A communication method characterized by including. To the computer installed in the control device
For a terminal device that repeatedly transmits one data using a pre-allocated radio resource, at least two sets of parameters to be used for the repeated transmission, said at least two of the terminal devices. A program for notifying at least two sets, indicating that one of the sets should be used to perform the repetitive transmission. To the computer installed in the terminal device
Receive at least two sets of parameters from the controller that should be used to iteratively transmit a piece of data using pre-allocated radio resources.
The repeat transmission is performed using one of the at least two sets.
Program for.

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