Base stations, terminal equipment, communication systems, methods, and programs

Abstract

The present disclosure provides a base station, a terminal device, a communication system, a method, and a program that contribute to reduction of electric power consumption. A base station (11) according to an aspect is provided with a processor and a transceiver. The processor is configured to cause the transceiver to: transmit, to a terminal device (12), a message including information indicating that information indicating an opportunity for receiving control information includes a plurality of sets of parameters indicating the frequency of the opportunity of receiving the control information; and receive from the terminal device (12) a response message with respect to the message.

Description

[Technical Field]

[0001] This disclosure relates to base stations, terminal equipment, communication systems, methods, and programs. [Background technology]

[0002] In wireless communication, the User Equipment (UE) intermittently receives data from the base station. For example, Patent Document 1 describes a terminal device that receives multiple candidate DRX settings from the base station and changes the DRX setting used for standby depending on the time of day. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-165328 [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.331 V16.4.1 (2021-03), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Radio Resource Control (RRC) protocol specification (Release 16) ”. [Overview of the project] [Problems that the invention aims to solve]

[0005] One of the purposes of this disclosure is to provide base stations, terminal devices, communication systems, methods, and programs that contribute to reducing power consumption. It should be noted that this purpose is only one of several purposes that the various embodiments disclosed herein seek to achieve. Other purposes or problems and novel features will be revealed in the description herein or in the accompanying drawings. [Means for solving the problem]

[0006] A base station according to one embodiment includes a processor and a transceiver, wherein the processor is configured to cause the transceiver to send a message to a terminal device, which includes information indicating that information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of the opportunity to receive the control information, and to receive a response message to the message from the terminal device.

[0007] A terminal device according to one embodiment includes a processor and a transceiver, wherein the processor is configured to cause the transceiver to receive a message from a base station that includes information indicating an opportunity to receive control information, which includes a set of parameters indicating the frequency of the opportunity to receive the control information, and to cause the base station to send a response message to the message.

[0008] A communication system according to one embodiment includes a base station and a terminal device, the base station includes a first processor and a first transceiver, the first processor is configured to cause the first transceiver to send a message to the terminal device that includes information indicating an opportunity to receive control information, which includes a plurality of sets of parameters indicating the frequency of the opportunity to receive the control information, the terminal device includes a second processor and a second transceiver, the second processor is configured to cause the second transceiver to receive the message from the base station and to send a response message to the message to the base station.

[0009] A method according to one embodiment is a method performed by a base station, which includes sending a message to a terminal device that includes information indicating that information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of the opportunity to receive the control information, and receiving a response message to the message from the terminal device.

[0010] A method according to one embodiment is a method performed by a terminal device, which includes receiving a message from a base station that includes information indicating that information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of the opportunity to receive the control information, and transmitting a response message to the base station for the message.

[0011] One embodiment of the program is a program that causes a computer to send a message to a terminal device that includes information indicating that information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of such opportunities to receive control information, and to receive a response message from the terminal device to the message.

[0012] One embodiment of the program is a program that receives a message from a base station that includes information indicating an opportunity to receive control information, which includes a set of parameters indicating the frequency of such opportunities to receive control information, and causes a computer to send a response message to the base station. [Effects of the Invention]

[0013] This disclosure provides base stations, terminal devices, communication systems, methods, and programs that contribute to reducing power consumption. [Brief explanation of the drawing]

[0014] [Figure 1] This is a diagram showing an example configuration of a communication system according to Embodiment 1. [Figure 2] This is a block diagram showing an example configuration of a communication device according to Embodiment 1. [Figure 3] This is a sequence diagram showing an example of the operation of the communication system according to Embodiment 1. [Figure 4] This figure shows an example configuration of the search space IE according to Embodiment 2. [Figure 5] This figure shows an example configuration of the search space IE according to Embodiment 2. [Figure 6] This figure shows a first example of modification to the search space IE according to Embodiment 2. [Figure 7] This figure shows a second example of modification to the search space IE according to Embodiment 2. [Figure 8] This figure shows a third example of the modification of the search space IE according to Embodiment 2. [Figure 9] This figure shows a fourth example of modification to the search space IE according to Embodiment 2. [Figure 10] This figure shows an example of a common reception timing for multiple search spaces according to Embodiment 4. [Figure 11] This shows an example implementation of PDCCH-Config IE. [Figure 12] Figure 11 shows an example of adding multiple sets of search space parameters: period, offset, and duration, in the SearchSpaceExt-v_xy IE. [Figure 13] Figure 11 shows another example of a PDCCH-Config IE implementation. [Figure 14] Figure 13 shows an example of adding search space parameters to the SearchSpaceExt-v_xy IE. [Figure 15A] This shows an example configuration for SearchSpace IE. [Figure 15B] This shows an example configuration for SearchSpace IE. [Figure 16] This is a block diagram showing an example configuration of a communication device according to each embodiment. [Modes for carrying out the invention]

[0015] Embodiments of the present disclosure will be described below with reference to the drawings. Note that the following description and drawings have been omitted and simplified as appropriate for clarity of explanation. Furthermore, in the following drawings, the same elements are denoted by the same reference numerals, and redundant explanations have been omitted where necessary. Also, unless otherwise specified, in this disclosure, "at least one of A or B (A / B)" may mean any one of A or B, or both A and B. Similarly, when "at least one" is used for three or more elements, it may mean any one of these elements, or any multiple elements (including all elements).

[0016] Embodiment 1 (Communication system configuration) Figure 1 shows an example configuration of a communication system according to Embodiment 1. The communication system 10 is, for example, a fifth-generation mobile communication system (5G system). The 5G system is NR (New Radio Access), which is fifth-generation radio access technology. Note that the communication system 10 is not limited to a fifth-generation mobile communication system, but may be a different mobile communication system such as an LTE (Long Term Evolution) system, an LTE-Advanced system, or a sixth-generation mobile communication system.

[0017] The communication system 10 comprises a base station 11 and a terminal device 12. The terminal device 12 is, for example, user equipment (UE). Although only one base station 11 and one terminal device 12 are shown in Figure 1, the communication system 10 may comprise multiple base stations 11 and terminal devices 12. The base station 11 and the terminal device 12 are capable of wireless communication.

[0018] Base station 11 may be, for example, a gNB. A gNB is a node that terminates the NR user plane and control plane protocols for the UE and connects to 5GC via an NG interface. Alternatively, base station 11 may be an ng-eNB (LTE evolved NodeB). An ng-eNB is a node that terminates the E-UTRA (Evolved Universal Terrestrial Radio Access) user plane and control plane protocols for the UE and connects to the 5G core network (5GC: 5G Core network) via an NG interface. Base station 11 may also be a CU (Central Unit) in a C-RAN (cloud RAN) configuration, or a gNB-CU. A gNB-CU is a logical node that hosts the gNB's RRC (Radio Resource Control) protocol, SDAP (Service Data Adaptation Protocol) protocol, and PDCP (Packet Data Convergence Protocol) protocol. Alternatively, the gNB-CU is a logical node that hosts the RRC and PDCP protocols for en-gNB, which control the operation of one or more gNB-DUs (gNB-Distributed Units). The gNB-CU terminates the F1 interface that connects to the gNB-DU. Alternatively, the base station 11 may be a CP (Control Plane) Unit, or a gNB-CU-CP (gNB-CU-Control Plane). The gNB-CU-CP is a logical node that hosts the control plane portion of the RRC protocol and the PDCP protocol for the gNB-CU for en-gNB or gNB. The gNB-CU-CP terminates the E1 interface that connects to the gNB-CU-UP (gNB-CU-User Plane) and the F1-C interface that connects to the gNB-DU. The gNB-CU-UP is a logical node that hosts the user plane portion of the PDCP protocol for the gNB-CU for en-gNB. The gNB-CU-UP terminates the E1 interface, which connects to the gNB-CU-CP, and the F1-U interface, which connects to the gNB-DU.

[0019] The base station 11 may be an eNB or an eNB-CU. Furthermore, the base station 11 may be an EUTRAN (Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network) node or an NG-RAN (Next Generation Radio Access Network) node. An EUTRAN node may be an eNB or an en-gNB. An NG-RAN node may be a gNB or an ng-eNB. An en-gNB provides protocol termination for the NR user plane and control plane to the UE and operates as a secondary node in EN-DC (NR Dual Connectivity).

[0020] Furthermore, in Figure 1, base station 11 provides (serves) at least one cell. Base station 11 operates that cell, connects to and communicates with terminal devices 12 located within that cell. Note that the way this cell is operated changes depending on the actions performed by base station 11.

[0021] Figure 2 is a block diagram showing an example configuration of communication equipment comprising a base station 11 and a terminal device 12. The communication equipment 100 includes a communication unit 101 and a control unit 102. The communication unit 101 and the control unit 102 may be software or modules whose processing is performed by a processor executing a program stored in memory. Alternatively, the communication unit 101 and the control unit 102 may be hardware such as a circuit or chip.

[0022] The communication unit 101 connects to other communication devices (e.g., base stations or UEs) included in the access network and performs various types of information transmission and reception by communicating with them.

[0023] The control unit 102 executes various processes of the communication device 100 by reading and executing various information and programs stored in memory. The control unit 102 processes according to any or all of the setting information, such as various information elements (IE), various fields, and various conditions, contained in the message received by the communication unit 101. The control unit 102 is configured to execute processing of multiple layers. Multiple layers may include a Physical layer, a MAC (Media Access Control) layer, an RLC (Radio Link Control) layer, a PDCP layer, an RRC layer, and a NAS (non-Access Stratum) layer. The above-described example of the communication system configuration is common to Embodiment 1-2.

[0024] Figure 3 is a sequence diagram showing an example of the operation of the communication system according to Embodiment 1. The operation example of the communication system 10 will be described below using Figure 3.

[0025] In step S1, the base station 11 sends a message to the terminal device 12 that includes information indicating an opportunity to receive control information, which includes multiple sets of parameters indicating the frequency of such opportunities. The terminal device 12 receives this message. This message may or may not include further information about the multiple sets of parameters. The terminal device 12 may or may not change the frequency of opportunities to receive control information, which is set internally in the terminal device 12, as a trigger for receiving this message. If it does not change the frequency, the terminal device 12 will change the frequency of opportunities to receive control information based on another trigger. The terminal device 12 may also have information about multiple sets of parameters already stored in it at the stage when it receives the message. Alternatively, the terminal device 12 may not have information about multiple sets of parameters stored in it at the stage when it receives the message, but may internally store the information about multiple sets of parameters included in the message. In other words, the message may be an instruction to the terminal device 12 to initialize the parameter sets, or an instruction to update the parameter set settings.

[0026] The set of multiple parameters may, for example, each define a search space. A search space is a period in which the terminal device 12 receives control information transmitted from the base station 11 to the terminal device 12 (for example, the Active time of DRX (Discontinuous Reception)), and is a control information reception opportunity in which the terminal device 12 may receive control information. For example, the period indicated by the search space includes one or more CORESETs (physical resources for transmitting PDCCH (Physical Downlink Control Channel)), and multiple PDCCHs are multiplexed and transmitted in each CORESET. The terminal device 12 detects DCI (Downlink Control Information) by receiving and decoding these PDCCHs in a brute-force manner. The search space is changed by changing the set of parameters that the terminal device 12 sets internally. Changing the search space means changing at least one parameter that determines the properties of the search space. The parameters that determine the properties of the search space may be, for example, at least one of the period of the search space, the offset of the search space, or the duration of the search space per period, but the examples of parameters are not limited to these. Furthermore, the trigger for changing the search space may be, for example, the frequency of information transmission from the base station 11 (details are described in Embodiment 2), or other events such as the power consumption of the terminal device 12 may also serve as triggers.

[0027] In step S2, the terminal device 12 can send a response message to the base station 11 as a response to the received message. The base station 11 receives this response message.

[0028] In Embodiment 1, the base station 11 transmits a message to the terminal device 12 that includes information indicating that the information indicating the opportunity to receive control information includes a set of parameters indicating the frequency of the opportunity to receive control information. The terminal device 12 can change the opportunity to receive control information based on the information contained in the message. The more frequently the opportunity to receive control information is received, the greater the power consumption of the terminal device 12. Therefore, in Embodiment 1, changing the frequency of the opportunity for the terminal device 12 to receive control information contributes to suppressing the power consumption of the terminal device.

[0029] Next, Embodiment 2 will be described. Embodiment 5 provides a specific example of the communication system shown in Embodiment 1.

[0030] Embodiment 2 The communication system in Embodiment 2, as shown in Figure 1, comprises a base station 11 and a terminal device 12. This base station 11 is a gNB in ​​5G and can transmit DCI, which is control information, to the terminal device 12 via PDCCH. The DCI allows for destination identification, and the DCI addressed to the terminal device 12 contains control information addressed to the terminal device 12.

[0031] Base station 11 configures the search space IE as a period of k s , the search space offset O s , and the duration T of the search space per cycle s Each of these can be set. s and O s We collectively refer to this as monitoringSlotPeriodicityAndOffset, and T s This is also referred to as duration. The explanation of the search space is as described in paragraph 0026.

[0032] FIG. 4 is a diagram showing a configuration example of a search space IE. In FIG. 4, one square represents one time slot (hereinafter, also simply referred to as a slot), and the hatched slot represents an opportunity to receive PDCCH. In this example, k s = 8, O s = 2, T s = 2.

[0033] In the search space IE, the slots (PDCCH reception opportunities) in which the terminal device 12 can receive (monitor) PDCCH in one cycle are represented as follows.

Number

Number

Number

Number

Number

[0034] Using the parameters shown above, the frequency of the PDCCH reception opportunity is the ratio of the duration of the search space per cycle to the period of the search space, and is T s / k sThis is the result. For example, in the example in Figure 4, the frequency at which PDCCH can be received in one cycle is 2 / 8. The power consumption of terminal device 12 related to PDCCH reception is thought to be roughly proportional to this ratio. Therefore, by reducing this ratio, the power consumption of terminal device 12 related to PDCCH reception can be reduced. In addition, terminal device 12 also starts receiving PDSCH (Physical Downlink Shared Channel) in parallel with PDCCH reception. Therefore, not only PDCCH reception but also PDSCH reception can be reduced.

[0035] In Embodiment 2, the terminal device 12 each determines the frequency of PDCCH reception opportunities (T s / k s The search space can be autonomously changed so that the ) changes. For details, one search space IE can have monitoringSlotPeriodicityAndOffset(k s ,O s ), duration(T s Multiple sets of the following can be configured. Each set is assigned an identification index (let's call it i). The range of i is {0..maximum number of configurable sets - 1}. Because the search space is configured in this way, it does not affect the settings of other search spaces that have been configured in advance. In addition, the terminal device 12 receives the search space sets in advance from the base station 11 in the manner shown in paragraphs 0024-0026 and stores them in the memory of the terminal device 12.

[0036] The usage, range, etc., of each parameter in the search space for each i can be adapted from the settings described above. Specifically, in monitoringSlotPeriodicityAndOffset_i, the period of the search space is k s,i , the search space offset is O s,i It is represented as T. s,i It is represented as follows.

[0037] In this search space IE, the slots (PDCCH reception opportunities) in which terminal device 12 can receive PDCCH in one cycle are represented as follows:

number

number

[0038] Figure 5 shows an example of the configuration of the search space IE. In Figure 5, one square represents one slot, and hatched slots represent PDCCH reception opportunities. In this example, k s,i =8, O s,i =2, T s,i = 2

[0039] One example of how to set the index is to use the existing monitoringSlotPeriodicityAndOffset and duration for search spaces where index=0, and set different monitoringSlotPeriodicityAndOffset and duration for search spaces where index is 1 or greater. monitoringSlotPeriodicityAndOffset and duration may also be initialized when index is the maximum or minimum value (e.g., 0).

[0040] The following describes two examples of shifting the PDCCH reception frequency. Here, we assume that the index is set to the search space frequency parameter ID, and that a larger index indicates a lower PDCCH reception frequency. The parameters used are P i Mi Further introduction will be implemented. i This represents the length of the interval for measuring the number of DCI detections in a search space when a search space with index=i is set. i The unit is the number of slots, and its range is, for example, {1..2560}. Here, 2560 is k s,i This is an example of the maximum value of M. i This is section P i This represents the threshold for the number of DCI detections in [the system]. Also, in the implementation example described later, P i M i These are also written as countPeriod and dciCount, respectively. Furthermore, in the following example, T s,i / k s,i It is assumed that there are two different types of search spaces, T s,i / k s,i There may be three or more different search spaces. The search space frequency parameter is a parameter that indicates the frequency of opportunities to receive control information, with a period k. s,i , offset O s,i , the duration of the search space per cycle T s,i , P i M i In addition, N, which will be discussed later i This may include. Terminal device 12 stores a set of search space frequency parameters for each index.

[0041] (1) Example of shifting the PDCCH reception frequency from high frequency to low frequency When terminal device 12 first performs PDCCH reception with a search space setting where index (search space frequency parameter ID) = i, length P i The number of DCIs addressed to itself detected in the search space within the counting interval is counted. The DCIs counted may be, for example, only those associated with this search space, but are not limited to them. In this case, the total number of detected DCIs is M. iIf the value is less than the maximum index, terminal device 12 autonomously changes its search space setting from index=i to index=j, where j=i+1. However, if i is already the maximum index, then j=i. At this time, base station 11, which is a gNB, also autonomously changes its search space setting to index=j.

[0042] Figure 6 shows a first example of a change to the search space IE. In this example, terminal device 12 has two types of search space frequency parameter settings, with index=0 {k s,0 =2,O s,0 =0,T s,0 =1,P0=8,M0=1}0 and {k with index=1} s,1 =4,O s,1 =2,T s,1 =1,P1=16,M1=1}1 is received in advance from base station 11. When index=0, the PDCCH reception frequency is 1 / 2, and when index=1, the PDCCH reception frequency is 1 / 4. The numbers assigned to each slot are the slot numbers shown in (7).

number

number

[0043] The terminal device 12 first sets a DCI count interval (n) of length P0=8. f Search space frequency parameter setting for index=0 (=0, during the period of slot numbers 0-7) {k s,0 =2,O s,0 =0,T s,0PDCCH reception is performed using the search space setting =1}0. PDCCH reception opportunities in this count interval are at the timings of slot numbers 0, 2, 4, and 6, which are indicated by hatching in Figure 6. If the number of times the terminal device 12 detects a DCI addressed to itself during the PDCCH reception opportunities in this count period is less than M0=1, the terminal device 12 autonomously switches the search space frequency parameter setting to index=1 as soon as this count period ends. That is, the terminal device 12 switches the search space frequency parameter setting to {k s,1 =4,O s,1 =2,T s,1 It autonomously transitions to {=1, P1=16, M1=1}.

[0044] In this example, the DCI count interval defined by P1 starts from the slot following the last slot of the DCI count interval defined by P0. That is, in Figure 6, n f When the number becomes 0 and slot number becomes 8, the DCI counting interval defined by P1 begins. During this counting interval, PDCCH reception opportunities occur when slot numbers are 10, 14, and 18, and their frequency is halved compared to the previous interval.

[0045] In the example shown above, even without the transmission of DCI to the terminal device 12 for its search space, the terminal device 12 can autonomously reduce the frequency of receiving PDCCH by half. Therefore, it is possible to halve the power consumption of the terminal device involved in receiving PDCCH.

[0046] Note that length P i This does not have to be an even number, as in the example in Figure 6, and may be an odd number. Figure 7 shows a second example of such a change to the search space IE. In this example, the terminal device 12 has two types of search space frequency parameter settings, with index=0 {k s,0 =2,O s,0 =0,T s,0 =1,P0=5,M0=1}0 and {k with index=1} s,1 =4,Os,1 =2,T s,1 The signal {=1, P1=10, M1=1} is received in advance from base station 11. When index=0, the PDCCH reception frequency is 1 / 2, and when index=1, the PDCCH reception frequency is 1 / 4. The explanation of the other parameters is the same as the explanation for Figure 6.

[0047] Initially, terminal device 12 receives PDCCHs using a search space setting with a search space frequency parameter setting of index=0 during a DCI counting interval of length P0=5. The PDCCH reception opportunities in this counting interval are at slot numbers 0, 2, and 4, which are indicated by hatching in Figure 7. If the number of times terminal device 12 detects a DCI addressed to itself during this counting period is less than M0=1, terminal device 12 autonomously switches the search space frequency parameter setting to index=1 after this counting period ends. The PDCCH reception opportunities in this counting interval are at slot numbers 6, 10, and 14, and the frequency is halved compared to the previous instance.

[0048] (2) Example of transitioning the PDCCH reception frequency from low frequency to high frequency Next, we will explain an example of transitioning the PDCCH reception frequency from low frequency to high frequency. In this explanation, the interval length P i The threshold for the number of DCI detections in the DCI count interval is the parameter N. i Introduction of parameter N i M i It is used as a threshold instead.

[0049] When terminal device 12 first performs PDCCH reception with a search space setting where index (search space frequency parameter ID) = i, length P i The number of DCIs addressed to this user detected in the search space within the counting interval is counted. The DCIs to be counted may be limited to those associated with this search space, for example, but are not limited to those. In this case, the total number of detected DCIs is N. iIf the above conditions are met, terminal device 12 autonomously changes its search space setting from index=i to index=j, where j=i-1. However, if i is already the minimum value of the index, then j=i. At this time, base station 11, which is a gNB, also autonomously changes its search space setting to index=j.

[0050] Figure 8 shows a third example of the change in the search space IE. In this example, terminal device 12 has two types of search space frequency parameter settings, with index=0 {k s,0 =2,O s,0 =0,T s,0 =1,P0=8,N0=2}0 and {k with index=1} s,1 =4,O s,1 =2,T s,1 The signal {=1, P1=16, N1=2} is received in advance from base station 11. When index=0, the PDCCH reception frequency is 1 / 2, and when index=1, the PDCCH reception frequency is 1 / 4. The other explanations in Figure 8 are the same as in Figure 6, so the explanations are omitted.

[0051] The terminal device 12 first sets a DCI count interval (n) of length P1=16. f =0, starting from the timing of slot number 8, n f The search space frequency parameter setting for index=1 (during the period up to the timing of slot number 3) {k s,1 =4,O s,1 =2,T s,1 PDCCH reception is performed using the search space setting =1}1. The number of PDCCH reception opportunities in this count interval is n f At =0, the slot numbers are 10, 14, and 18, and n fThe timing is when the slot number is 2 at n = 1. These timings are the timings indicated by hatching in FIG. 8. In the PDCCH reception opportunity during this DCI count period, when the number of times the terminal device 12 detects DCI addressed to itself is N1 ≥ 2 times, the terminal device 12 autonomously shifts the search space frequency parameter setting to the one with index = 0 immediately after the end of this count period. That is, the terminal device 12 autonomously shifts the search space frequency parameter setting to {k s,0 =2,O s,0 =0,T s,0 =1,P0 = 8,N0 = 2}0. The PDCCH reception opportunities in this count interval are the timings when the slot numbers are 4, 6, 8, 10 ··· at n f =1, and the frequency is twice that compared to the previous one.

[0052] In the example shown above, even if there is no transmission of DCI to the search space of the terminal device 12, the terminal device 12 can autonomously double the frequency of the opportunity to receive the PDCCH. Therefore, the terminal device 12 can receive data from the base station 11 when necessary.

[0053] i Regarding the DCI count interval defined by P i other definitions than those shown in the above example may be made. For example, in the search space IE, the DCI count interval defined by P

Number

Number

[0054] At this time, the length P iThe number of DCIs detected in the DCI count interval is defined as follows; at the end of this DCI count interval, regardless of which index (search space frequency parameter ID) of the search space frequency parameter was valid during the process, the length P i is the number of DCIs detected in all PDCCH reception opportunities during the DCI count interval.

[0055] Figure 9 is a diagram showing a fourth modification example of the search space IE. In this example, the terminal device 12 receives, from the base station 11, {k s,0 =2, O s,0 =0, T s,0 =1, P0 = 8, N0 = 2}0 with index = 0 and {k s,1 =4, O s,1 =2, T s,1 =1, P1 = 16, N1 = 2}1 with index = 1 as two types of search space frequency parameter settings. Also, at the timing after the number "8" attached to the slot in Figure 9, since the search space frequency parameter is changed, it should be noted that the numbers attached to these slots may be different from the slot numbers in the radio frame shown in (7). Other explanations in Figure 9 are the same as those in Figure 6, so the explanations are omitted.

[0056] Figure 9 shows an example of transitioning from DCI count interval 0 (n f =0, the period when the slot number is 0 to 7) defined with length P0 = 8 to interval 1 (n f =0, from the timing of slot number 8) defined with length P1 = 16 (the period related to the slots after the number "8" in Figure 9, that is, the period when the slot number is 0 to 15). f =0, the period when the slot number is 0 to 15).

[0057] Here, the PDCCH reception opportunities subject to counting the number of DCI detections in interval 1 (n f =0, the period when the slot number is 0 to 15) are the 6 slots with n f =0 and slot numbers = {0, 2, 4, 6, 10, 14}. These PDCCH reception opportunities are in interval 0 (n fThis also includes PDCCH reception opportunities included in the period (slot number 0-7, where =0). On the other hand, interval 1 (n f =0, starting from the timing of slot number 16, n f The number of PDCCH reception opportunities that are counted for DCI detection during the period up to when slot number is 11 is n f =0, slot number={18} and n f =1, and slot numbers ={2,6,10}, resulting in 4 slots.

[0058] The method by which the terminal device 12 transitions the PDCCH reception frequency from high frequency to low frequency, as shown in Figure 9, is as described in (1) above, and a detailed explanation is omitted.

[0059] The base station 11 may also count the number of DCI transmissions per search space for a given terminal device 12 and compare that number with a predetermined threshold. Based on the comparison result, it can autonomously switch parameters related to the frequency of PDCCH reception opportunities in a search space (search space frequency parameters). In other words, the base station 11 can perform the same processing as the terminal device 12 described above by using the number of DCI transmissions per search space instead of the number of DCI detections per search space in the processing of the terminal device 12 described above.

[0060] UEs sometimes perform operations to continuously receive multiple PDCCHs at a high frequency (e.g., every 1ms) to detect DCIs, but the power consumed by this receiving process is significant and should be reduced. In particular, if a PDCCH containing a DCI not addressed to itself is received, the power consumption related to that operation becomes wasted.

[0061] In Embodiment 2, the base station 11 transmits settings for multiple search spaces to the terminal device 12, and the terminal device 12 can change the search space using these settings. By changing the search space, the terminal device 12 can reduce its power consumption.

[0062] Here, in setting up multiple search spaces (setting parameters), T s / k s These may be different. This allows the terminal device 12 to switch between a search space with frequent reception opportunities and a search space with infrequent reception opportunities as needed, enabling both reduced power consumption and smooth communication.

[0063] Furthermore, the base station 11 may transmit multiple search space settings to the terminal device 12. This allows the base station 11 to determine the settings even if the terminal device 12 does not have the search space settings in advance. It also allows the base station 11 to manage the search space settings uniformly.

[0064] Furthermore, the terminal device 12 measures the frequency with which it receives PDCCH from the base station 11 and can change the search space settings based on that frequency. This allows the terminal device 12 to select between a search space setting that suppresses power consumption and a search space setting that enables high-frequency communication, depending on whether or not frequent communication with the base station 11 is required.

[0065] Furthermore, each of the multiple search space settings may have at least a period, a duration, and a search space offset. This allows for detailed configuration of the search space.

[0066] Furthermore, the terminal device 12 may receive DCI from the base station 11 during the period in which the terminal device 12 receives control information transmitted from the base station 11. This allows the terminal device 12 to receive control information regarding the search space settings without performing any special processing.

[0067] In Embodiment 2, the terminal device 12 receives the search space set from the base station 11 in advance and stores it in the memory unit of the terminal device 12. However, the search space set may be pre-configured and stored in both the base station 11 and the terminal device 12.

[0068] Embodiment 3 In the example shown in Embodiment 2, the base station 11 autonomously switches parameters related to the frequency of PDCCH reception opportunities in a search space (search space frequency parameters) based on the number of DCI transmissions per search space to a terminal device 12, and the terminal device 12 based on the number of DCI detections per search space (i.e., scheduling frequency). This is an example in which it is possible to transition search space frequency parameters without transmitting dynamic and explicit signaling via DCI from the base station 11 to the terminal device 12.

[0069] However, it is also possible to migrate the search space frequency parameters by using dynamic and explicit signaling via DCI from base station 11. Specifically, dynamic and explicit signaling via DCI can be used in conjunction with the DCI format (e.g., DCI format 1_1) by adding a field that notifies the index (search space frequency parameter ID) of the search space frequency parameter.

[0070] As a concrete example, the DCI format may have a field named "Search space periodicity-offset-duration indication," which may be set with, for example, 0, 1, ..., c(maxNrofAddPerOff-r_xy) bits, where c represents the ceiling function. The bit width for this field is determined to be c(log2(I)) bits for I greater than 1. I is the number of entries in the higher-layer parameter additionalPeridodicityAndOffsetList-r_xy if it is set, plus 1, and 0 bits if the higher-layer parameter is not set.

[0071] For example, base station 11 may notify terminal device 12 using DCI of the search space frequency parameter ID currently applied to the DCI count interval. Terminal device 12 may receive and store a set of each index of the search space frequency parameter from base station 11 at or before this time. Alternatively, a set of each index of the search space frequency parameter may be stored in advance within terminal device 12. In this state, terminal device 12 receives the DCI transmitted from base station 11 via PDCCH. Then, terminal device 12 can refer to the search space frequency parameter included in the received DCI and check whether the search space frequency parameter currently applied by base station 11 matches the search space frequency parameter applied by terminal device 12 itself. If it is determined that the two do not match, terminal device 12 can correct the search space frequency parameter it is currently operating based on the search space frequency parameter ID notified in the received DCI.

[0072] Embodiment 4 The search spaces at the base station 11 and the terminal device 12 may be out of sync. Embodiment 4 describes a process that can resolve this discrepancy.

[0073] Figure 10 shows an example of a common reception timing for multiple search spaces. The upper search space in Figure 10 is the search space with index=0 in Embodiment 2, and the lower search space is the search space with index=1 in Embodiment 2. The two search spaces are T s,i / k s,i Although they differ, slot numbers 2, 6, 10, ..., indicated by hatching in Figure 10, provide a common PDCCH reception opportunity.

[0074] Base station 11 transmits DCI, etc., at this common PDCCH reception opportunity. As a result, terminal device 12 can receive data from base station 11 regardless of which search space terminal device 12 is performing its reception operation in. For example, if base station 11 is using the search space with index=0 and terminal device 12 is using the search space with index=1, even if base station 11 transmits PDCCH at the timing of slot number 4, terminal device 12 will not receive that data.

[0075] If the base station 11 does not receive information from the terminal device 12 indicating that the terminal device 12 has received the PDCCH, it will transmit the DCI again at a common PDCCH reception opportunity such as slot numbers 6 and 10. As a result, the terminal device 12 can receive the DCI, and, based on the PDCCH reception frequency, it can switch the search space from index=1 to index=0 as shown in Embodiment 2, thereby making the search space used the same as that used by the base station 11.

[0076] Furthermore, if base station 11 transmits a DCI during a common PDCCH reception opportunity, but terminal device 12 does not transmit information indicating that it has received the PDCCH, base station 11 determines that the search space timings of base station 11 and terminal device 12 are mismatched. As a result, base station 11 performs control to synchronize either its own search space timing or the search space timing of terminal device 12. Therefore, the search spaces of both base station 11 and terminal device 12 are aligned, enabling smooth communication.

[0077] (Implementation example) The following examples illustrate implementations of the search space settings shown in Embodiment 2, using Figures 11-15B. While the following implementation examples are assumed to conform to the standards described in Non-Patent Document 1, other standards may also be applied.

[0078] Figure 11 shows an example implementation of PDCCH-Config IE. In Figure 11, the underlined list of SearchSpaceExt-v_xy represents the information introduced by this disclosure.

[0079] Here, PDCCH-Config IE may be included in the RRC Reconfiguration or RRC Setup message transmitted from base station 11 to terminal device 12. Here, the RRC Reconfiguration message is a command for modifying the RRC connection, as described in section 6.2.2 of Non-Patent Document 1, and the RRC Setup message is a message used to establish SRB1 (Signaling Radio Bearer 1), as described in section 6.2.2 of Non-Patent Document 1. However, as an alternative example, the RRC Setup message may be a message used when establishing the RRC connection, as described in section 5.3.3.1 of Non-Patent Document 1.

[0080] An RRC Reconfiguration or RRC Setup message has a structure similar to the following. The ">" in the following structure indicates the data hierarchy. >RRC Reconfiguration or RRC Setup message >>Cell group config IE >>>Serving cell config IE >>>>BWP-downlink Dedicated IE >>>>>PDCCH-Config IE The PDCCH-Config IE may be included in the RRC Reconfiguration or RRC Setup message in this manner. Furthermore, a terminal device 12 that receives an RRC Reconfiguration message containing the PDCCH-Config IE can send an RRC Reconfiguration complete message to the base station 11 as a response message. Similarly, a terminal device 12 that receives an RRC Setup message containing the PDCCH-Config IE can send an RRC setup complete message to the base station 11 as a response message.

[0081] Figure 12 shows an example of adding multiple sets of search space parameters, period, offset, and duration, in the SearchSpaceExt-v_xy IE shown in Figure 11. In Figure 12, AdditionalPeridodicityAndOffsetList-r_xy shows the parameter list from index=1 onwards, AdditionalPeridodicityAndOffset-r_xy shows the parameters for each index, and additionalPeridodicityAndOffsetIdentity shows the index i. Then, countPeriod, dciCount1, and dciCount2 are shown in paragraphs 0040 and 0048 respectively. i M i ,N i This shows that (i≧1). However, dciCount2 is optional, in which case M i =N i In Figure 12, the underlined dciCount1_0, dciCount2_0, dciCount1, and dciCount2 represent the information introduced by this disclosure.

[0082] Figure 13 shows a different implementation example of PDCCH-Config IE than Figure 11. In Figure 13, SearchSpaceExt-v_xy is added to PDCCH-Config IE, but instead of a list, the parameters Period, offset, and duration are added as Period1, offset1, and duration1.

[0083] Figure 14 shows an example of adding search space parameters to the SearchSpaceExt-v_xy IE shown in Figure 13. In this example, the parameters period, offset, and duration are defined in two sets by adding another set with index=1 to the first set with index=0. In Figure 14, countPeriod_0, dciCount1_0, and dciCount2_0 are P0, M0, and N0, respectively. However, dciCount2_0 is optional, in which case M0=N0.

[0084] Also, monitoringSlotPeriodicityAndOffset_1,duration_1 are periods of 1 (k s,i ), offset 1(O s,i ), duration 1 (O s,i ) is shown. Also, countPeriod_1, dciCount1_1, and dciCount2_1 are P1, M1, and N1, respectively. However, dciCount2_1 is optional, in which case M1=N1. Furthermore, initialPeriodicityAndOffsetIdenity indicates the initial value of the index, and is 0 if no initial value exists. In Figure 14, the underlined dciCount1_0, dciCount2_0, dciCount1_1, and dciCount2_1 are the information introduced by this disclosure.

[0085] Figures 15A and 15B show an example configuration of the SearchSpace IE for the implementation example described above. This SearchSpace IE may use an existing one, or a new one may be used.

[0086] This disclosure is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, in Embodiment 2, if the DCI detected by the terminal device 12 in the DCI count interval described above is 0, the terminal device 12 updates the search space frequency parameter with an incremented search space frequency parameter ID in the next DCI count interval. Otherwise, the terminal device 12 can switch to the search space frequency parameter of the search space frequency parameter ID notified by the DCI from the next DCI count interval. When the terminal device 12 performs such processing, the parameter M used in Embodiment 2 i and N i This becomes unnecessary.

[0087] The technologies described herein are not limited to dedicated communication devices, but can be applied to any device having communication capabilities.

[0088] (Example hardware configuration) Next, the following describes hardware configuration examples of communication devices such as base stations, terminal devices, or UEs as described in the above-described embodiments. Figure 16 is a block diagram showing configuration examples of communication devices according to each embodiment. Referring to Figure 16, the communication device 100 includes an RF (Radio Frequency) transceiver 1001, a network interface 1003, a processor 1004, and a memory 1005. The RF transceiver 1001 performs analog RF signal processing to communicate with the UE. The RF transceiver 1001 may include multiple transceivers. The RF transceiver 1001 is coupled with an antenna 1002 and a processor 1004. The RF transceiver 1001 receives modulation symbol data (or OFDM (Orthogonal Frequency Division Multiplexing) symbol data) from the processor 1004, generates a transmit RF signal, and supplies the transmit RF signal to the antenna 1002. Furthermore, the RF transceiver 1001 generates a baseband received signal based on the received RF signal received by the antenna 1002 and supplies it to the processor 1004.

[0089] The network interface 1003 is used to communicate with network nodes (e.g., other core network nodes). The network interface 1003 may include, for example, a network interface card (NIC) compliant with the IEEE (Institute of Electrical and Electronics Engineers) 802.3 series.

[0090] The processor 1004 performs data plane processing and control plane processing, including digital baseband signal processing for wireless communication. For example, in the case of LTE and 5G, the digital baseband signal processing by the processor 1004 may include signal processing for the MAC layer and the Physical layer.

[0091] The processor 1004 may include multiple processors. For example, the processor 1004 may include a modem processor (e.g., a DSP (digital signal processor)) that performs digital baseband signal processing, and a protocol stack processor (e.g., a CPU (central processing unit) or an MPU (microprocessor unit)) that performs control plane processing.

[0092] Memory 1005 is composed of a combination of volatile and non-volatile memory. Memory 1005 may include multiple physically independent memory devices. Volatile memory is, for example, Static Random Access Memory (SRAM) or Dynamic RAM (DRAM), or a combination thereof. Non-volatile memory is Mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or hard disk drive, or any combination thereof. Memory 1005 may include storage located away from the processor 1004. In this case, the processor 1004 may access memory 1005 via the network interface 1003 or an I / O interface not shown.

[0093] The memory 1005 may store a software module (computer program) containing a set of instructions and data for performing processing by the communication device 100 as described in the above-described embodiments. In some implementations, the processor 1004 may be configured to read the software module from the memory 1005 and execute it to perform the processing of the communication device 100 as described in the above-described embodiments.

[0094] As described above, the one or more processors in each of the above embodiments execute one or more programs that include a set of instructions for causing a computer to perform the algorithm described with reference to the drawings. This process enables the signal processing method described in each embodiment.

[0095] The program, when loaded into a computer, includes a set of instructions (or software code) for causing the computer to perform one or more of the functions described in the embodiments. The program may be stored on a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, of a non-temporary computer-readable medium or a physical storage medium include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, CD-ROM, digital versatile disk (DVD), Blu-ray® disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited to, of a temporary computer-readable medium or a communication medium include electrically, optically, acoustically, or otherwise propagating signals.

[0096] In this specification, User Equipment (UE) (or including mobile station, mobile terminal, mobile device, or wireless device, etc.) is an entity connected to a network via a wireless interface.

[0097] Some or all of the above embodiments may also be described as follows, but are not limited to the following: (Note 1) Processor and Equipped with a transceiver, The processor, in relation to the transceiver, The terminal device is instructed to send a message containing information indicating that the information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of such opportunities to receive control information. The terminal device is configured to receive a response message to the message, Base station. (Note 2) The aforementioned set of parameters has different ratios of the duration of the search space per period to the period of the search space. The base station described in Appendix 1. (Note 3) The processor causes the transceiver to transmit information of the multiple sets of parameters with different ratios toward the terminal device. The base station described in Appendix 2. (Note 4) In each of the sets of parameters, the period, the duration, and the search space offset are set, The base station described in Appendix 3. (Note 5) The processor instructs the transceiver to transmit data toward the terminal device at the timing when the terminal device receives data, based on a set of multiple parameters. The base station described in Appendix 3 or 4. (Note 6) If the processor does not receive a message from the terminal device indicating that data has been received at the aforementioned timing, it determines that the timing of the search space at the base station and the timing of the search space at the terminal device are inconsistent. The base station described in Appendix 5. (Note 7) The processor is configured to cause the transceiver to transmit the message to the terminal device during the period in which the terminal device receives the control information transmitted from the base station. The base station described in Appendix 1 or 2. (Note 8) Processor and Equipped with a transceiver, The processor, in relation to the transceiver, A message is received from the base station that includes information indicating that the information indicating the opportunity to receive control information includes a set of parameters indicating the frequency of the opportunity to receive said control information. The system is configured to cause the base station to send a response message to the message, Terminal device. (Note 9) The aforementioned set of parameters has different ratios of the duration of the search space per period to the period of the search space. The terminal device described in Appendix 8. (Note 10) The processor causes the transceiver to receive information about the set of multiple parameters with different ratios. The terminal device described in Appendix 9. (Note 11) The processor measures the frequency with which it receives control information for the terminal device from the base station, and based on that frequency, changes the search space setting of the terminal device from the setting of the first set of parameters in the set of multiple parameters to the setting of the second set of parameters. The terminal device described in Appendix 10. (Note 12) The processor measures the frequency with which it receives the control information from the base station to the terminal device, regardless of whether the search space setting of the terminal device has been changed within the frequency count interval, and based on that frequency, changes the search space setting of the terminal device from the setting of the first set of parameters in the set of multiple parameters to the setting of the second set of parameters. The terminal device described in Appendix 11. (Note 13) The processor changes the search space setting of the terminal device from a first set of parameters having a first ratio to a second set of parameters having a second ratio greater than the first ratio, when the frequency at which the control information is received from the base station to the terminal device is greater than or equal to a predetermined threshold. The terminal device described in Appendix 11 or 12. (Note 14) The processor changes the search space setting of the terminal device from a first set of parameters having a first ratio to a second set of parameters having a second ratio smaller than the first ratio, when the frequency at which the control information is received from the base station to the terminal device is less than a predetermined threshold. The terminal device described in Appendix 11 or 12. (Note 15) In each of the settings of the set of parameters, the period, the duration, and the offset of the search space are set, The terminal device described in Appendix 10 or 11. (Note 16) The processor is configured to cause the transceiver to receive the message from the base station during the period when the terminal device receives the control information transmitted from the base station. Terminal devices as described in Appendix 8 or 9. (Note 17) Base station and A terminal device is provided, The aforementioned base station is The first processor, A first transceiver, The first processor provides the first transceiver with respect to: The system is configured to cause the terminal device to send a message containing information indicating that the information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of such opportunities to receive control information. The aforementioned terminal device is The second processor, Equipped with a second transceiver, The second processor provides the second transceiver with respect to: The aforementioned message is received from the base station. The base station is configured to send a response message to the message, Communication system. (Note 18) The aforementioned set of parameters has different ratios of the duration of the search space per period to the period of the search space. The communication system according to claim 17. (Note 19) A message is sent to the terminal device, containing information indicating that the information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of such opportunities to receive control information. The terminal device receives a response message to the message. A method performed by a base station, including the following. (Note 20) A message is received from the base station, which includes information indicating that the information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of such opportunities to receive control information. A response message to the aforementioned message is sent to the aforementioned base station. A method performed by a terminal device, including the following. (Note 21) A message is sent to the terminal device, containing information indicating that the information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of such opportunities to receive control information. The terminal device receives a response message to the message. A program that causes a computer to perform a task. (Note 22) A message is received from the base station, which includes information indicating that the information indicating an opportunity to receive control information includes a set of parameters indicating the frequency of such opportunities to receive control information. A response message to the aforementioned message is sent to the aforementioned base station. A program that causes a computer to perform a task.

[0098] While the present disclosure has been described above with reference to embodiments, the present disclosure is not limited thereto. Various modifications to the structure and details of the present disclosure may be made that can be understood by those skilled in the art within the scope of the disclosure.

[0099] This application claims priority based on Japanese Patent Application No. 2022-041939, filed on 16 March 2022, and incorporates all of its disclosures herein. [Explanation of symbols]

[0100] 10 Communication Systems 11 Base station 12 Terminal device

Claims

1. Processor and Equipped with a transceiver, The processor, in relation to the transceiver, A message is sent to the terminal device indicating that information indicating an opportunity for the terminal device to receive control information includes a set of parameters indicating the frequency of such opportunities, and the set of parameters is accompanied by information that constitutes a count interval for the number of times the control information has been received by the terminal device, and parameters related to switching between the sets of parameters indicating the frequency of such opportunities, The terminal device receives a response message sent in response to the aforementioned message. The processor counts the number of transmissions of the control information to the terminal device in the transmission opportunity corresponding to the opportunity for the terminal device to receive the control information during the count interval, and changes the transmission opportunity from the setting of the first set of parameters in the set of parameters to the setting of the second set of parameters based on the number of transmissions and the parameters related to the switching. Base station.

2. The aforementioned set of parameters has different ratios of the duration of the search space per period to the period of the search space. The base station according to claim 1.

3. The processor causes the transceiver to transmit information of the multiple sets of parameters with different ratios toward the terminal device. The base station according to claim 2.

4. Processor and Equipped with a transceiver, The processor, in relation to the transceiver, A message is received from the base station, which includes information indicating that the information indicating the opportunity to receive control information includes a set of parameters indicating the frequency of the opportunity to receive the control information, and the set of parameters is accompanied by information that constitutes a count interval for the number of times the control information has been received, and parameters related to switching between the sets of parameters indicating the frequency of the opportunity to receive the control information. The base station is instructed to send a response message to the message. The processor, in the count interval, counts the number of times it receives the control information addressed to itself in reception opportunities configured by the set of parameters, and based on the number of receptions and the parameters related to the switching, changes the reception opportunity from the setting of the first set of parameters in the set of multiple parameters to the setting of the second set of parameters. Terminal device.

5. The aforementioned set of parameters has different ratios of the duration of the search space per period to the period of the search space. The terminal device according to claim 4.

6. Base station and A terminal device is provided, The aforementioned base station is The first processor, A first transceiver is provided, The first processor provides the first transceiver with respect to: A message is sent to the terminal device indicating that information indicating an opportunity for the terminal device to receive control information includes a set of parameters indicating the frequency of such opportunities, and the set of parameters is accompanied by information that constitutes a count interval for the number of times the control information has been received by the terminal device, and parameters related to switching between the sets of parameters indicating the frequency of such opportunities, The terminal device receives a response message sent in response to the aforementioned message. The first processor counts the number of transmissions of the control information to the terminal device in the transmission opportunity corresponding to the opportunity for the terminal device to receive the control information during the count interval, and based on the number of transmissions and the parameters related to the switching, changes the transmission opportunity from the setting of the first set of parameters in the set of parameters to the setting of the second set of parameters. The aforementioned terminal device is The second processor, Equipped with a second transceiver, The second processor provides the second transceiver with respect to: The aforementioned message is received from the base station. The base station is instructed to send a response message to the message. The second processor, in the count interval, counts the number of times it has received the control information addressed to itself in reception opportunities configured by the set of parameters, and based on the number of receptions and the parameters related to the switching, changes the reception opportunity from the setting of the first set of parameters in the set of multiple parameters to the setting of the second set of parameters. Communication system.

7. A message is sent to the terminal device, which includes information indicating that information indicating an opportunity for the terminal device to receive control information includes a plurality of sets of parameters indicating the frequency of the opportunity to receive the control information, and the set of parameters is accompanied by information that constitutes a count interval for the number of times the control information has been received by the terminal device, and parameters relating to switching of the set of parameters indicating the frequency of the opportunity to receive the control information. The response message sent from the terminal device in response to the aforementioned message is received. In the counting interval, the number of times the control information is transmitted to the terminal device during transmission opportunities corresponding to the opportunities for the terminal device to receive the control information is counted. Based on the number of transmissions and the parameters related to the switching, the transmission opportunity is changed from the setting of the first set of parameters in the set of parameters to the setting of the second set of parameters. A method performed by a base station, including the following.

8. A message is received from a base station, which includes information indicating that the information indicating the opportunity to receive control information includes a set of parameters indicating the frequency of the opportunity to receive the control information, and the set of parameters is accompanied by information that constitutes a count interval for the number of times the control information has been received, and parameters related to switching between the sets of parameters indicating the frequency of the opportunity to receive the control information. A response message to the message is sent to the base station. In the aforementioned counting interval, the number of times the control information addressed to itself is received in reception opportunities configured by the set of parameters is counted. Based on the number of receptions and the parameters related to the switching, the reception opportunity is changed from the setting of the first set of parameters in the set of multiple parameters to the setting of the second set of parameters. A method performed by a terminal device, including the following.

9. A message is sent to the terminal device, which includes information indicating that information indicating an opportunity for the terminal device to receive control information includes a plurality of sets of parameters indicating the frequency of the opportunity to receive the control information, and the set of parameters is accompanied by information that constitutes a count interval for the number of times the control information has been received by the terminal device, and parameters relating to switching of the set of parameters indicating the frequency of the opportunity to receive the control information. The response message sent from the terminal device in response to the aforementioned message is received. In the counting interval, the number of times the control information is transmitted to the terminal device during transmission opportunities corresponding to the opportunities for the terminal device to receive the control information is counted. Based on the number of transmissions and the parameters related to the switching, the transmission opportunity is changed from the setting of the first set of parameters in the set of parameters to the setting of the second set of parameters. A program that causes a computer to perform a task.

10. A message is received from a base station, which includes information indicating that the information indicating the opportunity to receive control information includes a set of parameters indicating the frequency of the opportunity to receive the control information, and the set of parameters is accompanied by information that constitutes a count interval for the number of times the control information has been received, and parameters related to switching between the sets of parameters indicating the frequency of the opportunity to receive the control information. A response message to the message is sent to the base station. In the aforementioned counting interval, the number of times the control information addressed to itself is received in reception opportunities configured by the set of parameters is counted. Based on the number of receptions and the parameters related to the switching, the reception opportunity is changed from the setting of the first set of parameters in the set of multiple parameters to the setting of the second set of parameters. A program that causes a computer to perform a task.

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