RU2786420C1 - User terminal and method for radio communication - Google Patents

Abstract

FIELD: wireless communication.

SUBSTANCE: invention relates to a user terminal and to a method for radio communication in next-generation mobile communication systems. According to the solution proposed, user terminal comprises a reception section configured to monitor a first descending control channel based on the search space configuration for the frequency band wherein channel detection is applied; and a control section configured to change the search space configuration based on the result of detection of the first descending control channel.

EFFECT: possibility of proper communication in an unlicensed band.

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Description

The field of technology to which the invention belongs

The present invention relates to a user terminal and a radio communication method in next generation mobile communication systems.

State of the art

In the Universal Mobile Telecommunications System (UMTS) network, Long-Term Evolution (LTE) specifications have been developed to further increase the data rate, provide lower latency, etc. (see non-patent document 1). In addition, in order to further improve throughput, development, etc. LTE (Third Generation Partnership Project (3GPP, from the English. Third Generation Partnership Project), version (English Release) 8 and version 9), specifications for advanced LTE (English LTE-Advanced) (3GPP version 10-14) have been developed.

LTE successor systems are also being studied (for example, the so-called "5th generation mobile communication system (5G)", "5G plus (+)", "New Radio (English New Radio, NR)", "3GPP version 15 ( or later)" and so on).

In the existing LTE system (for example, versions 8 to 12), the specifications were made based on the assumption that the system operates exclusively in the frequency range (called the licensed band, licensed carrier, licensed component carrier (licensed component carrier)) and etc.), a licensed communication service provider (operator). For example, 800 MHz, 1.7 GHz, 2 GHz, etc. are used as licensed SS.

Existing LTE systems (eg Release 13) support the use of a frequency band other than the licensed band described above (also called unlicensed band, unlicensed carrier, unlicensed CC) to extend the frequency range. It is assumed that the unlicensed band is, for example, the 2.4GHz band, the 5GHz band, etc., in which Wi-Fi (registered trademark) and Bluetooth (registered trademark) can be used.

More specifically, version 13 supports carrier aggregation (CA) which combines a carrier (CC) in the licensed band and a carrier (CC) in the unlicensed band. Communication made in this way using the unlicensed band together with the licensed band is called License-Assisted Access (LAA).

List of cited literature

Non-Patent Documents

Non-Patent Document 1:

Non-Patent Document 1: 3GPP TS 36.300 V8.12.0 "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); General description; Stage 2 (Issue 8)", April 2010

Disclosure of the essence of the invention

Technical problem

In future radio systems (e.g. 5G, 5G+, NR and version 15 (or later)) the transmission device (which is e.g. a base station in the downlink (DL) and is e.g. a user terminal in the uplink (UL) performs listening (also called Listen Before Talk (LBT), Clear Channel Assessment, Carrier Detection, channel discovery, channel access procedure, etc.) to check whether or not another machine (e.g., base station, user terminal, Wi-Fi machine, or the like) is transmitting before transmitting data in an unlicensed band.

It is possible that such radio communication systems are subject to regulations or requirements in the unlicensed band in order to coexist with another system in the unlicensed band.

However, if the operation in the unlicensed band is not clearly defined, the corresponding communication in the unlicensed band may not be available, for example, operation that does not comply with the rules under certain communication conditions, reduction in the efficiency of the use of radio resources, and the like.

Thus, the purpose of the present invention is to provide a user terminal and a radio communication method that performs proper communication in the unlicensed band.

Solution

A user terminal according to an aspect of the present invention comprises a receiving section configured to monitor a first downlink control channel based on a search space configuration for a frequency band in which channel detection is applied; and a control section configured to reconfigure the search space based on the detection result of the first downlink control channel.

Beneficial Effects of the Invention

According to one aspect of the present invention, it is possible to properly perform communication in the unlicensed band.

Brief description of the drawings

In FIG. 1 is a diagram showing an example of the first downlink method.

In FIG. 2 is a diagram showing an example of the second downlink method.

In FIG. 3 is a diagram showing an example of PDCCH dynamic monitoring.

In FIG. 4 is a diagram showing an example of PDCCH monitoring using two SS configurations.

In FIG. 5 is a diagram showing an example of PDCCH monitoring using three SS configurations.

In FIG. 6 is a diagram showing an example of a block diagram of a radio communication system according to one embodiment.

In FIG. 7 is a diagram showing an example of a block diagram of a base station according to one embodiment.

In FIG. 8 is a diagram showing a block diagram example of a user terminal according to one embodiment.

In FIG. 9 is a diagram showing an example of a hardware structure of a base station and a user terminal according to one embodiment.

Carrying out the invention Unlicensed range

In the unlicensed band (for example, the 2.4GHz band or the 5GHz band), for example, it is assumed that a plurality of systems, such as a Wi-Fi system, an LAA support system (LAA system), etc., coexist, and thus Thus, it is possible that collision avoidance and/or interference control in transmission between multiple systems is necessary.

For example, in a Wi-Fi system that uses an unlicensed band, Carrier Sense Multiple Access (CSMA) is used for collision avoidance and/or interference control. In CSMA /CA before transmission, a certain duration of "Distributed access Inter Frame Space (DIFS)" is set, and the transmission device performs data transmission after checking the absence of another transmission signal (carrier sense).After data transmission, the transmission device waits ACKnowledgement from the receiving machine When an ACK cannot be received within a certain amount of time, the transmitting machine determines that a collision has occurred and retransmits.

In the LAA of existing LTE systems (e.g., Release 13), a data machine performs LBT to check whether another machine (e.g., base station, user terminal, Wi-Fi device, or the like) is transmitting before transmitting data in an unlicensed band .

The transmission apparatus may be, for example, a base station (eg, gNB (gNodeB)) in the downlink (DL), and may be, for example, a user terminal (eg, user equipment (UE, from English. User Equipment)) in the uplink (UL). The receiving apparatus for receiving data from the transmitting apparatus may be, for example, a user terminal in the downlink, and may be, for example, a base station in the uplink.

In the LAA of existing LTE systems, a transmission unit starts data transmission after a certain period (eg, a period immediately after or after a grace period) after detecting that another unit has not transmitted (idle state) in the LBT.

The following four categories are defined as channel access methods in LTE LAA.

- Category 1: The node transmits without performing LBT.

- Category 2: The node performs carrier sensing at a fixed time before transmission and then transmits when the channel is empty.

- Category 3: The node randomly generates a value (random backoff) from a certain range before transmitting, then re-performs carrier sensing at a fixed time of the discovery slot, and then transmits when the channel is empty via slots with a value that can be checked.

- Category 4: The node randomly generates a value (random backoff) from a certain range before transmitting, then re-performs carrier sensing at a fixed time of the discovery slot, and then transmits when the channel is empty via slots with a value that can be checked. The node changes the range of the random backoff value (collision window size) depending on the condition of a link failure due to a link conflict with another system.

For LBT control, LBT performance is studied depending on the length of the gap (non-transmission period, period during which the received power is a certain threshold value or less, etc.) between two transmissions.

An NR system that uses the unlicensed band may be referred to as an NR-Unlicensed (U) system, an NR LAA system, etc. There is a possibility that NR-U also uses dual connectivity (DC) between the licensed band and the unlicensed band, standalone (SA) for the unlicensed band, etc.

In NR-U, a base station (eg, gNB) or UE obtains a transmission opportunity (TxOP) when the LBT result corresponds to an idle state and performs the transmission. The base station or UE does not transmit when the LBT result corresponds to the busy state (LBT-busy). The transmission opportunity time is referred to as Channel Occupancy Time (COT).

An NR-U is being studied that uses a signal including at least a Synchronization Signal (SS)/Physical Broadcast Channel (SSB) block (SSB). .SS block)). With regard to operation in the unlicensed band using this signal, the following issues are currently being studied.

- the absence of a gap in the time range in which the signal is transmitted in at least one beam,

- filling the occupied bandwidth,

- minimizing the time the channel is occupied by the signal, and

- a feature that facilitates quick access to the channel.

A signal is studied that includes a reference signal (RS, from the English Reference Signal) of channel state information (CSI, from the English Channel State Information), a set of SSB packets (a set of SSB blocks), a set of control resources (from the English COntrol REsource SET (CORESET)) and PDSCH associated with SSB in one continuous burst. This signal may be referred to as a discovery reference signal (DRS, NR-U DRS, etc.).

CORESET associated with SSB may be referred to as Remaining Minimum System Information (RMSI)-CORESET, CORESET #0, etc. The RMSI may be referred to as System Information Block 1 (SIB1). The SSB associated PDSCH may be a RMSI Carry PDSCH (RMSI PDSCH) or may be a PDSCH scheduled using a PDCCH (DCI having a CRC scrambled with System Information (SI) - a temporary identifier radio networks (RNTI, from the English Radio Network Temporary Identifier)) in RMSI-CORESET.

An SSB having a different SSB index may be transmitted using a different beam (the transmission beam of the base station). SSB as well as RMSI PDCCH and RMSI PDSCH corresponding to SSB may be transmitted using the same beam.

A node (eg, base station, UE) in NR-U coexists with another system or another operator, and thus starts transmission after checking that the channel is empty (clear) in LBT.

After successful completion of the LBT, the node may continue to transmit for a certain period of time from the start of the transmission. However, it should be noted that when a transmission is interrupted for a certain amount of time or more in the middle of a transmission, there is a possibility that another system is using the channel, and thus another LBT is needed before the next transmission. The available continuous transmission period depends on the priority class in the LBT or LBT category being used. The priority class may be the size of the conflict window for the random backoff, and the like. The shorter the LBT period (the higher the priority class), the shorter the available continuous transmission period.

The node must transmit in a wide range in accordance with the norm (regulation) of the transmission bandwidth in the unlicensed range. For example, the bandwidth norm in Europe is 80% or more of the system bandwidth. There is a possibility that a narrowband transmission will collide without being detected by another system or another operator performing wideband LBT.

It is preferable that the node transmits in as short a time as possible. Each of the plurality of coexisting systems reduces the channel busy time, and thus the plurality of systems can efficiently share resources.

It is preferable that the base station in NR-U transmits another beam (beam index, SSB index) of SSB, RMSI PDCCH (PDCCH for scheduling RMSI PDSCH) associated with SSB, and RMSI PDSCH by using the widest possible band in the shortest possible time . Therefore, the base station can apply a high priority class (LBT category with a short LBT period) for SSB/RMSI (DRS) transmission, and thus success in LBT can be expected with a high probability. The base station transmits in a wide range, thereby facilitating the bandwidth requirement. The base station also transmits in a short time, which avoids transmission interruption.

The bandwidth (UE channel bandwidth) of the original downstream (DL) bandwidth part (BWP) for NR-U is studied, which is 20 MHz. This is because the bandwidth for Wi-Fi, which is a coexisting system, is 20 MHz. In this case, SSB, RMSI PDCCH and RMSI PDSCH must be within the 20 MHz bandwidth.

In NR-U DRS, there is no break in the transmission period of at least one beam, thus preventing another system from interrupting the transmission period.

The NR-U DRS may be transmitted cyclically regardless of whether there are UEs in the active state and UEs in the idle state. Therefore, the base station can perform cyclic transmission of the signal necessary for the channel access procedure by using a simple LBT, and thus the UE can quickly access the NR-U cell.

NR-U DRS limits the required number of channel accesses and places the signal at a short time to achieve a short channel busy time. NR-U DRS can support NR-U for standalone mode (SA).

Broadband mode

For both the downlink (DL) and uplink (UL), a bandwidth greater than 20 MHz can be supported in a plurality of serving cells. For NR-U, support for a bandwidth configuration wider than 20 MHz for the serving cell is being studied.

For downlink operation, the following mode options are being studied based on fractional bandwidth (BWP) on a carrier having a bandwidth greater than 20 MHz.

- Option 1a: a set of BWPs are configured, then a set of BWPs are activated, and then the PDSCH is transmitted on one or more BWPs.

- Option 1b: multiple BWPs are configured, then multiple BWPs are activated, and then the PDSCH is transmitted over one BWP.

- Option 2: multiple BWPs are configured, then one BWP is activated, and then when the channel purity estimate (CCA) of the entire BWP in the base station is successful, the PDSCH is transmitted on the BWP.

- Option 3: multiple BWPs are configured, then one BWP is activated, and then the PDSCH is transmitted on the part of the BWP in which the CCA in the base station is successful.

Here, the CCA can perform an estimate for each 20 MHz band.

The UE may assume the presence of a signal such as DMRS on the PDCCH or a group common (GC)-PDCCH to detect a transmission burst from the serving base station. The PDCCH may be a single UE PDCCH (UE-specific PDCCH, normal PDCCH). The GC-PDCCH may be a PDCCH shared by one or more UEs (common multicast PDCCH for UEs).

In the unlicensed band, there are cases where the LBT periodically does not transmit a transmission burst, and thus blind decoding (blind detection) is not required to reduce the power at the UE and detect the transmission burst. First, the UE performs DMRS detection and may perform blind decoding upon DMRS detection. Such two steps of blind decoding using DMRS detection need not be essential to the UE.

Options 2 and 3 of the options above, using one active BWP, have less of an impact on specifications, as does NR version 15.

As shown in FIG. 1 (transmission spectra), when one active BWP has four LBT subbands and option 2 (first downlink method) is used, the base station performs LBT on each of the four LBT subbands, and then when all LBT results are in an idle state ( successful) (result of LBT A), a transfer can be made in the active BWP. When the LBT result on any of the subbands corresponds to a busy state (failure) (LBT result B), the base station does not transmit in the active BWP.

As shown in FIG. 2 (transmission spectra), when one active BWP has four subbands and option 3 (second downstream transmission method) is used, the base station performs LBT on each of the four subbands, and then when all LBT results are in the idle state, transmission can be performed in active BWP. When the LBT result on any of the subbands corresponds to a busy state, the base station may transmit on a subband other than the specified subband. Here, assume that one active BWP includes four contiguous subbands #0, #1, #2, and #3. When the LBT results on all subbands #0 to #3 are idle (LBT result A), the base station may transmit on contiguous subbands #0 to #3. When the LBT result on only subband #0 corresponds to a busy state (LBT result B), the base station can transmit on contiguous subbands #1, #2, and #3. When the LBT result on subband #1 only corresponds to a busy state (LBT result C), the base station may transmit on subbands #0, #2, and #3. The range between subbands #0 and #2 is a gap, and the range available for transmission is discontinuous.

The LBT subbands may have a certain bandwidth. The specific bandwidth may be one of the bandwidths defined for coexisting systems. For example, the specified bandwidth may be 20 MHz.

PDCCH monitoring in NR-U

In NR-U, the base station (eg, gNB) may transmit in a certain period after success in LBT, and thus may not always perform downlink transmission in the serving cell.

Even though the base station starts transmission immediately after LBT is successfully performed, if the UE does not monitor the PDCCH at this time, the UE cannot acknowledge the transmission, and thus it is possible that the UE performs PDCCH monitoring with fine temporal granularity. Increasing the PDCCH monitoring frequency by the UE increases the power consumption of the UE. It should be noted that the use of multiple PDCCH monitoring events in one slot is an optional feature in Release 15.

Thus, a UE is being studied that monitors a reference signal such as DMRS, which can be monitored with lower power consumption and more time granularity than the slot prior to the start of the downlink transmission in the serving cell, instead of PDCCH monitoring, which estimates that the downlink transmission in the serving cell cell started upon detection of the reference signal, and which monitors the PDCCH with finer temporal granularity than the slot through the boundary of the next slot (PDCCH dynamic monitoring).

As shown in FIG. 3, PDCCH dynamic monitoring may consist of the following three monitoring phases.

- Phase A: no PDCCH monitoring,

- Phase B: PDCCH mini-slot monitoring, and

- Phase C: regular PDCCH slot monitoring.

A mini-slot can be a period (a certain number of symbols) shorter than a slot.

Dynamic PDCCH monitoring can reduce the burden on the UE when monitoring the PDCCH for a serving NR-U cell.

Phase A is a state in which the transmission packet from the base station is not transmitted, for example, outside the COT of the base station. In phase A, the UE may not perform PDCCH monitoring and may perform DMRS monitoring for the GC-PDCCH. The UE may determine the transition from phase A to phase B by detecting a transmission burst having DMRS for the GC-PDCCH from the serving base station. In the case where the expected number of DMRS is small, the DMRS monitoring load on the UE can be suppressed.

Phase B may be within the slot period in which the DMRS for the GC-PDCCH is detected. In this phase, the UE may perform DMRS monitoring for the PDCCH at the start of all mini-slots via the next slot boundary. The UE may acknowledge the duration (length) of the phase B time.

In other words, in phase B, in the first slot for a transmission burst, it is possible that the transmission time of the PDCCH changes depending on the success time in LBT, and after the PDCCH and PDSCH with a certain length are transmitted, the PDCCH and PDSCH are additionally transmitted in the remaining symbols. , and therefore it is preferable that a plurality of PDCCH monitoring events be configured.

After phase B, the UE switches the monitoring phase to phase C for PDCCH monitoring according to the same search space configuration as for HP Release 15.

In other words, in phase C, in a slot after the first slot outside the transmission burst, the same scheduling can be performed as in the NR frequency. For example, in the case of using eMBB, the PDCCH may be located in the header of each slot.

This operation makes it possible to start channel access immediately after success in LBT, and thus it is possible to suppress an increase in power consumption of the UE due to PDCCH monitoring.

In LTE-LAA, the downlink header is a sub-frame (1 ms) or slot (0.5 ms) boundary. The downlink header always includes a cell-specific reference signal (CRS). The PDCCH is mapped to the entire Component Carrier (CC) range. For example, the common PDCCH may report (notify) to the UE information (eg, the presence or absence of a transmission, the number of symbols in which a transmission is present, etc.) about the transmission in a subframe for the PDCCH and the next subframe, or may not report to the UE the specified information. The transmission of the common PDCCH is not essential.

The UE performs blind detection of CRS in slot cycle, and upon detection of CRS, the UE may perform blind discovery of PDCCH or common PDCCH, or may perform blind discovery of CRS and PDCCH in slot cycle from the beginning.

For NR-U, the possibility of using anything other than a slot boundary as a downlink header is being explored. When the UE continues to monitor the PDCCH and DMRS with more granularity than slot, the power consumption of the UE becomes high.

Assume that LBT is performed for each LBT subband (eg, 20 MHz), and a CC or BWP bandwidth can be configured that is wider than the LBT subband width. In this case, LBT is performed on a plurality of LBT subbands, and there is a possibility that the bandwidth for a transmission burst header differs depending on which LBT subbands the LBT has been successful on. It is possible that the UE performs monitoring on each LBT subband.

Thus, the inventors of the present invention came up with the idea of a method for suppressing an increase in UE power consumption due to PDCCH monitoring, as well as reducing the time from LBT success to channel access time.

Narrowing signals for monitoring with a high degree of granularity is preferred. Preferably, monitoring in the header of a transmission packet is performed for each LBT subband, and monitoring in a slot after the first slot for a transmission packet is performed in the band in which LBT was successful.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. The radio communication methods according to respective embodiments may be used individually or may be used in combination.

In the present invention, listening before talking (LBT), listening, channel purity estimation (CCA), carrier detection, channel detection, detection, channel access procedure, and shared spectrum channel access can be interpreted interchangeably.

In the present invention, frequency, range, spectrum, carrier, component carrier (CC), and cell can be interpreted interchangeably.

In the present invention, NR-U frequency, NR-U target frequency, NR-U band, common spectrum, unlicensed band, unlicensed spectrum, SCell LAA, LAA cell, Primary Cell (PCell), Primary Secondary Cell ( from English Primary Secondary Cell, PSCell), special cell (from English Special Cell, SpCell)), secondary cell (from English secondary cell, SCell) and the frequency range in which channel detection is applied can be interpreted interchangeably.

In the present invention, NR frequency, NR target frequency, licensed band, licensed spectrum, PCell, PSCell, SpCell, SCell, non-NR-U frequency, NR version 15, and a frequency band in which channel detection is not applied can be interpreted interchangeably.

Different frame structures may be used between the NR-U frequency and the NR frequency.

The radio communication system (NR-U system, LAA) may conform to the first radio standard (eg, NR, LTE, etc.) (or may support the first radio standard).

Another system (coexisting system, coexisting machine) that coexists with this radio communication system, and another radio communication machine (coexisting machine) can comply with the second radio standard such as Wi-Fi, Bluetooth (registered trademark), WiGig (registered trademark) , Wireless LAN (local area network, from the English Local Area Network), IEEE802.11 and LPWA (Low Power Wide Area Network from the English. Low Power Wide Area), other than the first radio standard (or may support the second radio standard). The coexisting system may be a system that receives interference from the radio communication system, or may be a system that interferes with the radio communication system.

In the present invention, the transmission burst, the downlink transmission burst, the first downlink transmission in the COT, and the downlink transmission from the base station can be interpreted interchangeably.

In the present invention, at least one of the PDCCH and GC-PDCCH may be referred to as a specific PDCCH, PDCCH, and so on. The DMRS for at least one of the PDCCH and GC-PDCCH may be referred to as DMRS for PDCCH, DMRS, and so on.

In the present invention, LBT subband, LBT band, active downlink, BWP part, subband, and partial band can be interpreted interchangeably.

In the present invention, monitoring, blind detection, blind decoding, and discovery attempt can be interpreted interchangeably.

Radio communication method

First Embodiment

A plurality of search space (SS) configurations may be configured for the UE, each having a plurality of different PDCCH monitoring periodicity portions. The UE may determine whether to use a specific SS configuration from a plurality of SS configurations based on the detection result of the specific PDCCH (may change the specific SS configuration or may switch the specific SS configuration). A particular PDCCH may be at least one of a GC-PDCCH and a PDCCH. The specific SS configuration may be the SS configuration used for phase A.

Phase A may be at least one of the following: a period before the detection (before detection) of a specific PDCCH, a period after notification of a transmission burst interruption from the serving base station by the detected specific PDCCH, a period after the end time of the transmission burst reported by the detected specific PDCCH , and a period during which a downlink transmission from the serving base station is not detected for a certain time.

Phase B may range from the detection of a particular PDCCH to the boundary of the first slot.

Phase C may be at or after the first slot boundary after a particular PDCCH has been detected.

Two SS configurations (eg, SS #1 and #2) for detecting a transmission packet may be configured for the UE. SS #1 and #2 may be a UE-specific search space (USS). SS #1 may be the default USS or may be the SS used for phases A and B, and the monitoring interval in SS #1 may be shorter than the slot length. SS #2 may be the SS used for phase C, and the monitoring frequency in SS #2 may be equal to the slot length.

In FIG. 4 is a diagram showing an example of PDCCH monitoring using two SS configurations.

In phases A and B, the UE may monitor SS #1 and need not monitor SS #2.

In phase C, the UE may monitor SS #2 and need not monitor SS #1.

Three SS configurations (eg, SS #0, #1, and #2) can be configured for the UE to detect a transmission packet. SS #0, #1 and #2 can be USS. SS #0 may be the default USS or may be the SS used for phase A, and the monitoring interval in SS #0 may be shorter than the slot length. SS #1 may be the SS used for phase B, and the monitoring period in SS #1 may be shorter than the slot length. SS #2 may be the SS used for phase C, and the monitoring frequency in SS #2 may be equal to the slot length.

In FIG. 5 is a diagram showing an example of PDCCH monitoring using three SS configurations.

In phase A, the UE may monitor SS #0 and need not monitor SS #1 and #2.

Whether the UE monitors a particular PDCCH based on SS #0 may be implementation dependent on the UE. The UE can only monitor DMRS based on SS #0 and need not monitor a specific PDCCH based on SS #0.

In phase B, the UE can monitor SS #1 and need not monitor SS #0 and #2.

The monitoring frequency of the PDCCH in SS #1 may be different from the monitoring frequency of the PDCCH in SS #0. The PDCCH monitoring cycle in SS #1 may be longer than the PDCCH monitoring cycle in SS #0. For example, the PDCCH monitoring cycle in SS #0 may be 2 symbols, and the PDCCH monitoring cycle in SS #1 may be 4 symbols.

In phase C, the UE may monitor SS #2 and need not monitor SS #0 and #1.

The SS configuration for monitoring at least one of phases A and B may be referred to as the first SS configuration. The configuration SS for monitoring in step C may be referred to as the second configuration SS.

The SS configuration for phases A and B and the SS configuration for phase C may be configured separately for the UE, or the SS configuration for phase A, the SS configuration for phase B, and the SS configuration for phase C may be configured separately for the UE. These SS configurations may be distinguished by different RRC information elements (IE) or may be distinguished by different field names.

The UE may determine, depending on whether the detection of a particular PDCCH is successful, the SS configuration to be monitored. For example, upon detecting a particular PDCCH, the UE may switch the SS configuration for phases A and B, or the SS configuration for phase B to the SS configuration for phase C. In other words, the UE may be implicitly indicated to switch the SS configuration by the particular PDCCH.

The UE may switch the SS configuration based on the indication to switch the SS configuration included in the DCI on the specific PDCCH. For example, upon detecting a handover indication, the UE may switch the SS configuration for phases A and B or the SS configuration for phase B to the SS configuration for phase C. In other words, the UE may be explicitly instructed to switch the SS configuration via a particular PDCCH.

According to this first embodiment, the PDCCH monitoring period before a specific PDCCH is detected is shorter than the PDCCH monitoring period after a specific PDCCH is detected, and thus the delay from success in LBT to the start of a transmission burst in the base station can be suppressed, and frequency utilization efficiency can be be raised. The UE increases the PDCCH monitoring period after detecting a specific PDCCH, and thus power consumption can be suppressed.

Second Embodiment

The UE may monitor the GC-PDCCH on the NR-U frequency.

The GC-PDCCH may be used to notify the transmission burst configuration on the NR-U frequency. For example, the GC-PDCCH may advertise the slot format by using a particular DCI format (eg, DCI format 2_0). The UE may confirm the duration (duration) of the downlink based on the slot format.

The UE may perform GC-PDCCH monitoring according to any of the following GC-PDCCH monitoring methods 1 or 2.

GC-PDCCH Monitoring Method 1

Whether the GC-PDCCH is transmitted on the NR-U frequency may be configured for the UE through higher layer signaling.

When the SS configuration for the GC-PDCCH is configured for the UE, the UE may monitor the GC-PDCCH based on the configured SS configuration. The SS configuration for the GC-PDCCH may be an SS configuration dedicated to the GC-PDCCH, or an SS configuration including a specific DCI format (e.g., DCI format 2_0, new DCI format for UE group notification, or new DCI format for NR-U frequency). ). The UE may confirm the transmission burst configuration from the serving base station based on the detection result of the GC-PDCCH. The result of the GC-PDCCH detection may be whether a GC-PDCCH was discovered, or it may be the reported content of the detected GC-PDCCH (DCI specific format).

When the SS configuration for the GC-PDCCH is not configured for the UE, the UE may confirm the transmission from the serving base station based on the detection result of the specific downlink transmission. The specific downlink may be at least one of PDCCH, DMRS, and a specific reference signal (RS, eg, CSI-RS). For example, when the SS configuration for the GC-PDCCH is not configured for the UE and the UE detects a specific downlink transmission, the UE may acknowledge the transmission from the serving base station. For example, when the SS configuration for the GC-PDCCH is not configured for the UE and the UE does not detect a specific downlink transmission, the UE may confirm that there is no transmission from the serving base station.

GC-PDCCH Monitoring Method 2

Monitoring of the GC-PDCCH on the NR-U frequency can always be configured for the UE.

The SS configuration for the GC-PDCCH may always be configured for the UE with respect to the NR-U frequency BWP, and the UE may monitor the GC-PDCCH based on the SS configuration. The UE may confirm the transmission burst configuration from the serving base station based on the detection result of the GC-PDCCH. The result of the GC-PDCCH detection may be whether a GC-PDCCH was discovered, or it may be the reported content of the detected GC-PDCCH (DCI specific format).

According to this second embodiment, a UE that uses the NR-U frequency can reliably receive the GC-PDCCH at the start of a transmission burst. The UE may confirm the transmission packet configuration.

Third Embodiment

A first CORESET associated with a first SS configuration to be monitored prior to detecting a specific PDCCH and a second CORESET associated with a second SS configuration to be monitored after detecting a specific PDCCH may be configured for the UE. When the width of the BWP at the NR-U frequency is greater than the width of the LBT subband, different rules may be defined for the first CORESET and the second CORESET.

Similar to the first embodiment, the first SS configuration may be used to monitor at least one of phases A and B. The second SS configuration may be used to monitor phase C.

The UE may be configured with a first SS configuration to monitor before detecting a particular PDCCH, a first CORESET associated with the first SS configuration, a second SS configuration for monitoring after detecting a specific PDCCH, and a second CORESET associated with the second SS configuration.

Multiple CORESETs can be associated with one SS configuration.

The above option 3 (second downlink method) can be used. The base station may perform LBT on each of the plurality of LBT subbands included in the BWP before transmitting the transmission burst, and may transmit the transmission burst by using at least one of the LBT subbands upon successful LBT. The base station may transmit the transmission burst by using all LBT subbands on LBT success, or may transmit the transmission burst by using a preconfigured LBT subband of the LBT subbands on LBT success.

When monitoring the first SS configuration, the UE does not confirm on which LBT subband the serving base station can transmit, and thus the UE can perform PDCCH candidate blind detection for each LBT subband.

A plurality of first CORESETs, each mapped to a plurality of different LBT subbands in the BWP, may be associated with the first SS configuration.

At least one first CORESET mapped to a plurality of different LBT subbands in a BWP may be associated with a first SS configuration. In this case, the UE may assume that the PDCCH candidate and DMRS are mapped to the corresponding LBT subband. In other words, the UE need not assume that the PDCCH and DMRS candidate are mapped to multiple LBT subbands.

When the UE monitors the second SS configuration, the decision on which LBT subband the serving base station can transmit has already been made, and thus the base station can report information regarding the LBT subband to be used for transmission. For example, a particular PDCCH may notify the UE of the LBT subband configuration.

A plurality of second CORESETs, each mapped to a plurality of different LBT subbands in the BWP, may be associated with the second SS configuration.

The UE may perform PDCCH monitoring by using the second CORESET mapped to the LBT subband based on the detected specific PDCCH and the second SS configuration. For example, the LBT subband based on the specific PDCCH detected may be the LBT subband with the specific PDCCH detected, or may be the LBT subband reported by the specific PDCCH detected.

At least one second CORESET mapped to a plurality of different LBT subbands in a BWP may be associated with a second SS configuration. In this case, the UE may assume that the PDCCH candidate and the DMRS are mapped on at least one LBT subband. In other words, the PDCCH candidate and the DMRS need not be mapped to the same LBT subband. When the PDCCH and DMRS in the second SS configuration are mapped to a plurality of LBT subbands, wideband mapping can be performed compared to the first SS configuration, and thus the frequency diversity effect and channel estimation accuracy can be improved.

To switch the first SS configuration to the second SS configuration, the particular PDCCH may notify the UE of the second CORESET corresponding to the LBT subband with the successful LBT of the second CORESETs associated with the second SS configuration. The UE may monitor the PDCCH by using the reported second CORESET and the second SS configuration.

According to this third embodiment, downlink transmission in a frequency band wider than the LBT subband can be received on the NR-U frequency.

Fourth Embodiment

In the UE corresponding to the NR-U frequency, at least one of the functions of dynamic switching (change) of the SS configuration to be monitored (first embodiment) and GC-PDCCH monitoring (second embodiment) may be a mandatory function.

In a UE corresponding to an NR-U frequency, both dynamic switching of the SS configuration to be monitored and GC-PDCCH monitoring may be required functions.

In a UE corresponding to the NR-U frequency, GC-PDCCH monitoring may be a mandatory function. Dynamic switching of the SS configuration to be monitored may be an optional feature. The UE may report, as a capability to the UE, support for dynamic switching in the SS configuration to be monitored.

According to this fourth embodiment, the UE can reliably perform, on the NR-U frequency, at least one of dynamic switching in the SS configuration to be monitored and GC-PDCCH monitoring.

Radio communication system

The structure of a radio communication system according to one embodiment of the present invention will be described below. In this radio communication system, the radio communication method according to each embodiment of the present invention disclosed above may be used alone or may be used in combination for communication.

In FIG. 6 is a diagram showing an example of a block diagram of a radio communication system according to one embodiment. The radio communication system 1 may be a system that implements communication using a Long Term Evolution (LTE) scheme, a 5th generation New Radio (5G NR) mobile communication system, and the like, the specifications for which have been developed by the 3rd Generation Partnership Project (3GPP) .

The radio communication system 1 can support a dual connection (MR-DC, multi-RAT dual connectivity) between a plurality of radio access technologies (RAT). MR-DC may include dual connection (E-UTRA-NR (EN-DC) dual connection) between LTE (evolved universal terrestrial radio access) and NR, dual connection (NR-E- UTRA Dual Connectivity (NE-DC)) between NR and LTE, etc.

In EN-DC, the LTE Base Station (eNB) (E-UTRA) is the Master Node (MN) and the NR Base Station (gNB) is the Secondary Node (SN). In the NE-DC, the NR base station (gNB) is the MN and the LTE (E-UTRA) base station (eNB) is the SN.

The radio communication system 1 can support dual connection between multiple base stations in the same RAT (eg, dual connection (NR-NR Dual Connection (NN-DC)), where both MNs and SNs are NR Base Stations (gNBs).

The radio communication system 1 may comprise a base station 11, which forms a macro cell C1 with a relatively wide coverage area, and radio base stations 12 (12a - 12c), which are located in the macro cell C1 and form small cells C2, and which are narrower than the macro cell C1 . The user terminal 20 may be located in at least one cell. The location, number, and the like of each cell and user terminal 20 is by no means limited to the aspect shown in the diagram. Hereinafter, base stations 11 and 12 will be collectively referred to as "base stations 10" unless otherwise indicated.

User terminal 20 may be connected to at least one of a plurality of base stations 10. User terminal 20 may use at least one of carrier aggregation (CA) and dual connection (DC) using multiple component carriers ( SS, from English component carriers).

Each CC may be included in at least one of the first frequency band 1 (FR1) and the second frequency band 2 (FR2). Macro cell C1 may be included in FR1 and small cells C2 may be included in FR2. For example, FR1 may be the frequency range of 6 GHz or less (below 6 GHz), and FR2 may be the frequency range above 24 GHz (above 24 GHz). It should be noted that frequency ranges, definitions, etc. for FR1 and FR2 are not limited in any way, and, for example, FR1 may correspond to a frequency range that is higher than FR2.

In addition, the user terminal 20 can communicate in each SS using at least one of a time division duplex (TDD) and a frequency division duplex (FDD).

The plurality of base stations 10 may be connected by a wired connection (for example, an optical fiber according to the Common Public Radio Interface (CPRI), X2 interface, etc.) or a wireless connection (for example, NR communication). For example, when the NR link is used as a backhaul between base stations 11 and 12, the base station 11 corresponding to the higher level station may be referred to as "integrated access backhaul (IAB) donor". backhaul)", and the base station 12 corresponding to the relay station (relay) may be referred to as the "node 1AB".

Base station 10 may be connected to core network 30 through another base station 10 or directly. The core network 30 may include, for example, at least one of an evolved packet core (EPC), a 5G core network (5GCN), a next generation core (NGC), and etc.

The user terminal 20 may be a terminal supporting at least one of the communication schemes such as LTE, LTE-A, 5G, and so on.

In the radio communication system 1, a wireless access scheme based on orthogonal frequency division multiplexing (OFDM) may be used. For example, in at least one of the downlink (DL) and uplink (UL), cyclic prefix OFDM (CP-OFDM), discrete Fourier transform OFDM (DFT-s -OFDM, from English discrete Fourier transform spread OFDM), orthogonal frequency division multiple access (OFDMA, from English orthogonal frequency division multiple access), single carrier frequency division multiple access (SC-FDMA, from English. single carrier frequency division multiple access), etc.

The wireless access pattern may be referred to as a "waveform". Note that, in the radio communication system 1, a different wireless access scheme (eg, different single carrier transmission scheme, different multi-carrier transmission scheme) may be used for the uplink and downlink wireless access scheme.

In the radio communication system 1, the downlink common channel (Physical Downlink Shared Channel (PDSCH)) which is used by each user terminal 20 on a shared basis, the broadcast channel (Physical Broadcast Channel (PBCH)), the downlink control channel (Physical Downlink control channel (PDCCH)) etc.

In the radio communication system 1, uplink channels (Physical Uplink Common Channel (PUSCH)) used by each user terminal 20 on a shared basis, Uplink Control Channel (Physical Uplink Control Channel (PUCCH)), Random Access Channel (Physical random access channel (PRACH, from the English Physical Random Access Channel))), etc.

User data, higher-level control information, System Information Blocks (SIBs) and the like are transmitted over the PDSCH. User data, higher level management information, etc. transmitted over the PDSCH. Blocks of basic information (MIB, from the English. Master Information Blocks) are transmitted over the Strategic Missile Forces channel.

The lower layer control information may be transmitted on the PDCCH. For example, the lower layer control information may include downlink control information (DCI) including scheduling information of at least one of the PDSCH and PUSCH.

Note that the DCI for PDSCH scheduling may be referred to as "downstream assignment", "downstream DCI", etc., and the DCI for PUSCH scheduling may be referred to as "upstream grant", "upstream DCI", etc. It should be noted that PDSCH may be interpreted as "downstream data" and PUSCH may be interpreted as "upstream data".

A control resource set (CORESET) and a search space may be used for PDCCH discovery. CORESET corresponds to a resource for DCI lookup. The search space corresponds to the search area and the search method for PDCCH candidates. One CORESET may be associated with one or more search spaces. The UE may monitor the CORESET associated with the specific search space based on the search space configuration.

One search space may correspond to a PDCCH candidate corresponding to one or more levels of aggregation. One or more search spaces may be referred to as a "set of search spaces". It should be noted that "search space", "search space set", "search space configuration", "search space set configuration", "CORESET", "CORESET configuration", etc. in the present invention may be interpreted interchangeably.

Uplink control information (UCI) including at least one of channel state information (CSI), transmission acknowledgment information (which may be referred to as, for example, hybrid automatic repeat request (HARQ) acknowledgment -ACK, from hybrid automatic repeat request acknowledgment), ACK/NACK, etc.) and scheduling request (SR, from scheduling request), can be transmitted via PUCCH. Through the PRACH, random access preambles can be transmitted to establish connections with cells.

It should be noted that in the present invention, "downlink", "uplink", etc. may be mentioned without the words "link". In addition, various channels may be mentioned without adding the word "physical" at the beginning.

In the radio communication system 1, a synchronization signal (SS, from synchronization signal), a downlink reference signal (DL-RS, from English downlink reference signal), etc. can be transmitted. In the radio communication system 1, a cell-specific reference signal (CRS, from the English cell-specific reference signal), a reference signal of the channel state information (CSI-RS, from the English channel state information-reference signal) can be transmitted as DL-RS , demodulation reference signal (DMRS, from the English demodulation reference signal), positioning reference signal (PRS, from the English Positioning Reference Signal), phase tracking reference signal (PTRS, from the English phase tracking reference signal), etc.

The synchronization signal may be, for example, at least one of a primary synchronization signal (PSS, from the English primary synchronization signal) and a secondary synchronization signal (SSS, from the English secondary synchronization signal). A signaling block including an SS (PSS or SSS) and a RVSN (and a DMRS for the RVSN) may be referred to as an SS/PBCH block, an SS block (SSB), and so on. It should be noted that SS, SSB, etc. may also be referred to as a "reference signal".

In the radio communication system 1, a sounding reference signal (SRS), a demodulation reference signal (DMRS), etc. may be transmitted as an uplink reference signal (UL-RS). It should be noted that DMRS may be referred to as "user terminal-specific reference signal (UE-specific reference signal)".

Base station

In FIG. 7 is a diagram showing an example of the structure of a base station according to one embodiment. The base station 10 includes a control section 110, a transmission/reception section 120, a transmission/reception antenna 130, and a communication channel interface (transmission line interface) 140 . It should be noted that base station 10 may include one or more control sections 110, one or more transmit/receive sections 120, one or more transmit/receive antennas 130, and one or more communication channel interfaces 140.

It should be noted that the present example mainly shows functional blocks related to the distinctive parts of the present embodiment, and it is assumed that the base station 10 may also contain other functional blocks necessary for radio communication. Part of the processes of each section disclosed below may be omitted.

The control section 110 controls the entire base station 10. The control section 110 may be built with a controller, control circuit, or the like, characterized based on a general understanding of the technical field to which the present invention pertains.

The control section 110 may control signal generation, scheduling (eg, resource allocation, display), and so on. The control section 110 can control transmission and reception, measurement, etc. using the transmission/reception section 120, the transmission/reception antennas 130, and the communication channel interface 140. The control section 110 may generate data, control information, a sequence, etc., to be transmitted as a signal, and forwards the generated elements to the transmit/receive section 120. The control section 110 may perform call processing (setup, release, etc.) for communication channels, manage the state of the base station 10, and manage radio resources.

The transmit/receive section 120 may include a baseband section 121, a radio frequency (RF) section 122, and a measurement section 123. The baseband section 121 may include a transmission processing section 1211 and a reception processing section 1212. The transmit/receive section 120 may be constructed with a transmitter/receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transmit/receive circuit, or the like, characterized based on general knowledge in the technical field to which the the present invention.

The transmit/receive section 120 may be constructed as a single transmit/receive section, or may be constructed from a transmit section and a receive section. The transmission section may be built using the transmit processing section 1211 and the RF section 122. The receive section may be built using the receive processing section 1212, the RF section 122, and the measurement section 123.

The transmit/receive antennas 130 may be constructed with antennas, such as an antenna array, or the like, characterized based on general knowledge in the art to which the present invention pertains.

The transmission/reception section 120 may transmit the above-described downlink, synchronization signal, downlink reference signal, and the like. The transmit/receive section 120 may receive the above-described uplink, the uplink reference signal, and the like.

The transmit/receive section 120 may generate at least one of a transmit beam and a receive beam using digital beamforming (eg, precoding), analog beamforming (eg, phase rotation), and so on.

The transmission/reception section 120 (transmission processing section 1211) can perform packet data convergence protocol (PDCP) layer processing, radio link control (RLC) layer processing (for example, RLC transmission), media access control (MAC) layer processing (e.g., HARQ retransmission control), etc., for example, with respect to data and control information, etc. received from control section 110, can generate a bit string to send.

The transmission/reception section 120 (transmission processing section 1211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, Discrete Fourier Transform (DFT) processing (if necessary), fast inverse Fourier transform (IFFT) processing, precoding, digital-to-analog conversion, etc., on the bit string to be transmitted, and outputs the baseband signal.

The transmit/receive section 120 (RF section 122) can perform RF modulation, filtering, amplification, and so on. with respect to the baseband signal, and can transmit a signal in the radio frequency range through the antennas 130 transmit/receive.

On the other hand, the transmit/receive section 120 (RF section 122) may perform amplification, filtering, demodulation of the baseband signal, and so on. in relation to the signal in the radio frequency range received by the antennas 130 transmit/receive.

The transmit/receive section 120 (receive processing section 1212) may apply receive processing such as analog-to-digital conversion, fast Fourier transform (FFT) processing, inverse discrete Fourier transform (IDFT) processing (if necessary), filtering, inverse mapping, demodulation , decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, or PDCP layer processing, and so on. with respect to the received baseband signal to receive user data, and so on.

The transmission/reception section 120 (measurement section 123) may perform measurement related to the received signal. For example, the measurement section 123 may perform Radio Resource Management (RRM) measurement, Channel State Information (CSI) measurement, and so on. based on the received signal. The measurement section 123 can measure the received power (for example, the received power of the reference signal (RSRP, from the English Reference Signal Received Power)), the received quality (for example, the received quality of the reference signal (RSRQ, from the English Reference Signal Received Quality), the signal ratio - interference plus noise (SINR, from the English Signal to Interference plus Noise Ratio) or signal-to-noise ratio (SNR, from the English Signal to Noise Ratio), signal level (for example, the indicator of the received signal strength (RSSI, from the English Received Signal Strength Indicator)), channel information (eg, CSI), etc. The measurement results can be output to the control section 110 .

The link interface 140 can perform transmission/reception (backhaul signaling) of a signal with a machine included in the core network 30 or other base stations 10, etc., and receive or transmit user data (user plane data), control plane data etc. for user terminal 20.

It should be noted that the transmission section and the reception section of the base station 10 in the present invention can be built with at least one of the transmission/reception section 120 and the transmission/reception antennas 130.

User terminal

In FIG. 8 is a diagram showing an example of the structure of a user terminal according to one embodiment. The user terminal 20 includes a control section 210, a transmit/receive section 220, and a transmit/receive antenna 230. It should be noted that the user terminal 20 may include one or more control sections 210, one or more transmit/receive sections 220, and one or more transmit/receive antennas 230.

It should be noted that the present example mainly shows functional blocks related to the distinctive parts of the present invention, and it is assumed that the user terminal 20 may also contain other functional blocks necessary for radio communication. Part of the processes of each section disclosed below may be omitted.

The control section 210 controls the entire user terminal 20. The control section 210 may be built with a controller, control circuit, or the like, characterized based on general knowledge of the art to which the present invention pertains.

The control section 210 may control signal generation, display, and so on. The control section 210 can control transmission/reception, measurement, etc. using the transmission/reception section 220 and the transmission/reception antennas 230. The control section 210 may generate data, control information, a sequence, etc., to be transmitted as a signal, and may forward the generated elements to the transmit/receive section 220.

The transmit/receive section 220 may include a baseband section 221, an RF section 222, and a measurement section 223. The baseband section 221 may include a transmission processing section 2211 and a reception processing section 2212. The transmit/receive section 220 may be constructed with a transmitter/receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transmit/receive circuit, or the like, characterized based on general knowledge in the technical field to which the the present invention.

The transmit/receive section 220 may be constructed as a single transmit/receive section, or may be constructed with a transmit section and a receive section. The transmission section may be built using the transmission processing section 2211 and the RF section 222. The receiving section may be built using the reception processing section 2212, the RF section 222, and the measurement section 223.

The transmit/receive antennas 230 may be constructed with antennas, such as an antenna array, or the like, characterized based on general knowledge of the art to which the present invention pertains.

The transmit/receive section 220 may receive the above-described downlink, synchronization signal, downlink reference signal, and so on. The transmit/receive section 220 may transmit the above-described uplink, uplink reference signal, and so on.

The transmit/receive section 220 may generate at least one of a transmit beam and a receive beam using digital beamforming (eg, precoding), analog beamforming (eg, phase rotation), and so on.

The transmit/receive section 220 (transmit processing section 2211) may perform PDCP layer processing, RLC layer processing (eg, RLC retransmission control), MAC layer processing (eg, HARQ retransmission control), etc., for example, with respect to data and control information, etc. received from the control section 210 may generate a bit string for transmission.

The transmission/reception section 220 (transmission processing section 2211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, DFT processing (if necessary), IFFT processing, precoding , digital-to-analog conversion, etc., with respect to the bit string to be transmitted, and outputs the baseband signal.

It should be noted that the application or non-application of DFT processing may be based on a transform precoding configuration. The transmission/reception section 220 (transmission processing section 2211) may perform, for a specific channel (eg, PUSCH), DFT processing, as the above-described transmission processing, to transmit the channel using the DFT-s-OFDM waveform if transform precoding is turned on, and otherwise it is not required to perform DFT processing as the transfer process described above.

The transmit/receive section 220 (RF section 222) can perform RF modulation, filtering, amplification, and so on. with respect to the baseband signal, and can transmit a signal in the radio frequency range through the antennas 230 transmit/receive.

On the other hand, the transmit/receive section 220 (RF section 222) may perform amplification, filtering, demodulation of the baseband signal, and so on. in relation to the signal in the radio frequency range received by the antennas 230 transmit/receive.

The transmit/receive section 220 (receive processing section 2212) may apply a reception process such as analog-to-digital conversion, FFT processing, RDFT processing (if necessary), filtering, demapping, demodulation, decoding (which may include corrective decoding errors), MAC layer processing, RLC layer processing or PDCP layer processing, etc. with respect to the received baseband signal to receive user data, and so on.

The transmit/receive section 220 (measurement section 223) may perform a measurement related to the received signal. For example, the measurement section 223 may perform Radio Resource Management (RRM) measurement, CSI measurement, and the like based on the received signal. The measurement section 223 can measure received power (eg, RSRP), received quality (eg, RSRQ, SINR, SNR, signal strength (eg, RSSI), channel information (eg, CSI), etc. The measurement results can be output to the control section 210.

It should be noted that the transmission section and the reception section of the user terminal 20 in the present invention can be built with at least one of the transmission/reception section 220, the transmission/reception antennas 230, and the communication channel interface 240.

The transmit/receive section 220 may monitor the first downlink control channel based on a search space (SS) configuration for a frequency band in which channel discovery is applied. The control section 210 may reconfigure the search space based on the detection result of the first downlink control channel.

Control section 210 may use the first search space configuration to monitor the first downlink control channel, and may use the second search space configuration to monitor the second downlink control channel after detecting the first downlink control channel. The monitoring interval in the second search space configuration may be longer than the monitoring interval in the first search space configuration.

Detection may be performed on each of the plurality of subbands in a bandwidth portion (BWP) including the band for the first downlink control channel. At least one first control resource set (CORESET) associated with the first search space configuration may be mapped to a plurality of subranges. At least one second CORESET associated with the second search space configuration may be mapped to a subband based on a first downlink control channel outside said plurality of subbands.

The first downlink control channel may be a common group downlink control channel (eg, GC-PDCCH).

The control section 210 may have a mandatory function for at least one of monitoring a group common downlink control channel and reconfiguring a search space based on a detection result.

Hardware structure

It should be noted that the block diagrams used to describe the above embodiments illustrate blocks in functional units. These functional blocks (components) may be implemented in arbitrary combinations of at least one of hardware and software. Also, the implementation method of each function block is not limited to special cases. That is, each functional block may be implemented by a single piece of apparatus that is physically or logically connected, or may be implemented by connecting two or more physically or logically separate apparatus parts directly or indirectly (e.g., via wire, wireless, or the like) and using this many parts of the apparatus. The functional blocks may be implemented by combining software into the apparatus described above, or into a plurality of apparatuses described above.

Here, the functions include judgment, determination, decision, calculation, calculation, processing, inference, investigation, search, confirmation, reception, transmission, inference, access, resolution, selection, designation, establishment, comparison, guess, expectation, consideration. , transmission, notification, communication, forwarding, configuration, reconfiguration, selection (display), assignment, and the like, but the functions are by no means limited to these. For example, the functional block(s) for realizing the transmission function may be called a "transmission section (transmission block)", "transmitter", or the like. As described above, the implementation method of each component is not limited to particular cases.

For example, a radio base station, user terminal, etc., in accordance with an embodiment of the present invention, can function as a computer that performs the processes of the radio communication method in accordance with the present invention. In FIG. 9 is a diagram showing an example of a hardware structure of a base station and a user terminal according to one embodiment. At the physical level, the base station 10 and user terminal 20 described above may be formed as a computer apparatus that includes a processor 1001, a memory 1002, a storage device 1003, a communication apparatus 1004, an input apparatus 1005, an output apparatus 1006, a bus 1007, and so on.

It should be noted that in the present invention, words such as apparatus, circuit, device, section, block, etc. can be interpreted interchangeably. The hardware structure of base station 10 and user terminal 20 may be configured to include one or more of the apparatuses shown in the drawings, or may be configured not to include a portion of the apparatuses.

For example, although only one processor 1001 is shown, multiple processors may be provided. In addition, the processes may be executed with a single processor, or the processes may be performed simultaneously, sequentially, or in other manners with one or more processors. It should be noted that processor 1001 may be implemented with one or more chips.

Each function of base station 10 and user terminals 20 is implemented by, for example, allowing certain software(s) to be read on hardware such as processor 1001 and memory 1002, and allowing processor 1001 to perform communications control calculations by communication apparatus 1004, and controlling at least one of reading and writing data to memory 1002 and storage 1003.

The processor 1001 controls the entire computer through, for example, operating system operation. The processor 1001 may be configured with a central processing unit (CPU) that includes interfaces with peripheral equipment, a control apparatus, a calculation apparatus, a register, and so on. For example, at least a portion of the control section 110 (210) described above, the transmit/receive section 120 (220), etc. may be implemented using the processor 1001.

In addition, the processor 1001 reads programs (program codes), program modules, data, and so on. from at least one of the storage 1003 and the communications apparatus 1004 to the memory 1002 and performs various processes in accordance therewith. With regard to programs, programs are used that allow computers to perform at least a portion of the operations of the embodiments disclosed above. For example, control section 110 (210) may be implemented with control programs stored in memory 1002 and running on processor 1001, and other functional blocks may be implemented in a similar manner.

Memory 1002 is a computer-readable recording medium and may include, for example, at least one of read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), random access memory. (RAM) and other suitable storage medium. Memory 1002 may be referred to as a "register", "cache", "main memory" (primary storage), etc. The memory 1002 may store executable programs (program codes) and software modules, etc., for executing the radio communication method in accordance with one embodiment of the present invention.

The drive 1003 is a computer-readable recording medium and may be constructed using, for example, at least one of the following: floppy disk, floppy disk (floppy, registered trademark), magneto-optical disk (for example, a ROM on a compact disk ( CD-ROM), etc.), digital versatile disc, Blu-ray (registered trademark) disc, removable disc, hard drive, smart card, flash memory device (such as card, memory card, " key drive"), magnetic stripe, database, server, and other suitable storage medium. The drive 1003 may be referred to as "backup storage".

The communication apparatus 1004 is a hardware (transmitting/receiving device) for enabling communication between computers using at least one of wired and wireless networks, and may also be referred to as, for example, "network device", "network controller", "network card ”, “communication module”, etc. The communication apparatus 1004 may be configured to include a high frequency switch, a duplexer, a filter, a frequency synthesizer, and so on. to implement, for example, at least one of a frequency division duplex (FDD, from the English. Frequency Division Duplex) and a duplex with a time division (TDD, from the English. Time Division Duplex). For example, the transmit/receive sections 120 (220) described above, the transmit/receive antennas 130 (230), etc. may be implemented by the communications apparatus 1004. In the transmit/receive section 120 (220), the transmit section 120a (220a) and the receive section 120b (220b) may be implemented by being separated physically or logically.

The input apparatus 1005 is an input device that receives input from outside (eg, keyboard, mouse, microphone, switch, button, sensor, etc.). The output apparatus 1006 is an output device for enabling output data to be sent to the outside (eg, display, speaker, light-emitting diode (LED) indicator, etc.). It should be noted that the input apparatus 1005 and the output apparatus 1006 may be provided in a combined structure (eg, a touch panel).

In addition, these types of devices, including the processor 1001, the memory 1002, and others, are connected via a bus 1007 to transmit information. Bus 1007 may be implemented as a single bus or may be implemented as different tires for different parts of the apparatus.

Also, base station 10 and user terminal 20 may be built to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLU), a field programmable gate array (FPGA, from the English Field Programmable Gate Array), and part or all of the functional blocks can be implemented using hardware. For example, processor 1001 may be implemented with at least one of these pieces of hardware.

(options)

It should be noted that the terminology used in the present invention and the terminology necessary for understanding the present invention may be replaced by other terms having the same or similar meaning. For example, "channel", "symbol", and "signal" (or signaling) can be interpreted interchangeably. Also "signals" can be "messages". The reference signal may be abbreviated to "RS" and may be referred to as "pilot" or "pilot signal", etc., depending on which standards apply. In addition, a "component carrier" (CC) may be referred to as a "cell", "frequency carrier", "carrier frequency", etc.

A radio frame may consist of one or multiple periods (frames) in the time domain. Each of one or more periods (frames) that make up a radio frame may be referred to as a "subframe". In addition, a subframe may consist of one or more slots in the time domain. A subframe may have a fixed time duration (eg, 1 ms) independent of numerology.

Here, the numerology may be a communication parameter applied to at least one of the transmission and reception of a particular signal or channel. For example, numerology can mean at least one of subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering processing performed by the transceiver in the frequency domain. , specific windowing performed by the transceiver in the time domain, and so on.

A slot may consist of one or multiple time domain symbols (orthogonal frequency division multiplexing (OFDM) symbols or single carrier frequency division multiple access (SC-FDMA) symbols, etc.). In addition, the slot may represent a unit of time based on numerology.

A slot may include a plurality of minislots. Each minislot may consist of one or multiple symbols in the time domain. A mini-slot may be referred to as a "sub-slot". A mini-slot can consist of fewer symbols than the number of slots. The PDSCH (or PUSCH) transmitted per unit of time exceeding the mini-slot may be referred to as "PDSCH Map Type A (PUSCH)". The PDSCH (or PUSCH) transmitted using the mini-slot may be referred to as "PDSCH Map Type B (PUSCH)".

The radio frame, subframe, slot, minislot, and symbol express units of time in communication. Each of the radio frame, subframe, slot, minislot, and symbol may be referred to by other suitable terms. It should be noted that units of time such as frame, subframe, slot, mini-slot, and symbol in the present invention can be interpreted interchangeably.

For example, one subframe may be referred to as "TTI", multiple consecutive subframes may be referred to as "TTI", or one slot or one mini-slot may be referred to as "TTI". That is, at least one of the subframe and TTI may be a subframe (1 ms) in existing LTE, may be a shorter period than 1 ms (eg, 1 to 13 symbols), or may be a longer period of time, than 1 ms. It should be noted that the unit expressing the TTI may be referred to as "slot", "minislot", etc., instead of "subframe".

In the present description, TTI means, for example, the minimum unit of scheduling time in radio communication. For example, in LTE systems, the base station schedules the allocation (provision) of radio resources (such as the frequency band and transmission power available for each user terminal) to the user terminal in units of TTI. It should be noted that the definition of TTI intervals is not limited to this.

TTIs may be units of transmission time of channel-encoded data packets (transport blocks), code blocks, or code words, or may be a unit of processing in scheduling, link adaptation, and so on. It should be noted that when TTIs are set, a time interval (eg, the number of symbols) in which transport blocks, code blocks, and codewords or the like are actually displayed may be shorter than the TTIs.

It should be noted that, in the case where one slot or one mini-slot is referred to as "TTI", one or more TTIs (i.e., one or more slots or one or more mini-slots) may represent a minimum unit of scheduling time. . In addition, the number of slots (number of mini-slots) that constitutes the minimum unit of scheduling time can be adjusted.

A TTI having a time duration of 1 ms may be called "normal TTI" (TTI in LTE versions 8-12), "long TTI", "normal subframe", "long subframe", "slot", etc. A TTI shorter than a normal TTI may be referred to as "short TTI", "short TTI", "partial or fractional TTI", "short subframe", "short subframe", "minislot", "subslot", "slot", etc.

It should be noted that a long TTI (eg, normal TTI, subframe, etc.) may be interpreted as a TTI having a time duration greater than 1 ms, and a short TTI (eg, short TTI, etc.) may be interpreted as a TTI , having a TTI length less than the TTI length of the long TTI and equal to or greater than 1 ms.

Resource block (RB, from the English. Resource Block) is a unit of allocation (provision) of resources in the time domain and frequency domain and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in the RB may be the same regardless of the numerology, and may be, for example, 12. The number of subcarriers included in the RB may be determined based on the numerology.

Also, a RB may include one or multiple symbols in the time domain and may be one slot, one minislot, one subframe, or one TTI in length. One TTI and one subframe, etc. may consist of one or more resource blocks.

It should be noted that one or more RB blocks can be called a "physical resource block" (PRB, from the English. Physical Resource Block), "sub-carrier group" (SCG, from the English. Sub-Carrier Group), "resource element group" (REG , from the English Resource Element Group), “PRB pair”, “RB pair”, etc.

In addition, a resource block may consist of one or more resource elements (RE, from the English Resource Element). For example, one RE may correspond to a radio resource region of one subcarrier and one symbol.

The bandwidth portion (BWP) (which may be referred to as "fractional bandwidth" or so on) may be a subset of contiguous common resource blocks (common RBs) for a particular numerology on a particular carrier. Here, the common RB may be indicated by the RB index based on the common carrier reference point. The PRB may be defined with a particular BWP and may be numbered in the BWP.

The BWP may include UL BWP (uplink BWP) and DL BWP (downlink BWP). One or multiple BWPs may be configured on a single carrier for a UE.

At least one of the configured BWPs may be active and the UE does not need to assume the transmission/reception of a particular signal/channel outside of the active BWPs. It should be noted that "cell", "carrier", etc. in the present invention may be interpreted as "BWP".

It should be noted that the structures of radio frames, subframes, slots, minislots, symbols, etc. disclosed above are only examples. For example, structures such as the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of mini-slots included in a slot, the number of symbols and RBs included in a slot or mini-slot, the number of subcarriers included in the composition of the RB, the number of characters in the TTI, the length of the character and the length of the cyclic prefix (CP, from the English Cyclic Prefix) can be changed in various ways.

Also, the information, parameters, etc. disclosed in the present invention may be presented in absolute terms, or in relative terms with respect to certain values, or may be presented in the form of other relevant information. For example, radio resources may be defined using specific indexes.

Names used for parameters, etc. in the present invention are not limiting in any way. In addition, mathematical expressions using these parameters, etc., may differ from the expressions explicitly disclosed in the present invention. For example, since the various channels (PUCCH, PDCCH, etc.) and information elements can be identified by any suitable names, the various names assigned to these various channels and information elements are in no way limiting.

The information, signals, etc. disclosed in the present invention may be represented using a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, microcircuits, and the like, which may be referred to in the foregoing description, may be represented as voltages, electric currents, electromagnetic waves, magnetic fields or particles, optical fields or photons, or any combination of them.

Information, signals, etc. may be output from higher levels to lower levels and/or from lower levels to higher levels. Information, signals, and the like may enter and/or exit through a plurality of network nodes.

Information, signals, etc., which are inputs and/or outputs, may be stored in a specific location (eg, memory) or may be controlled using a control table. Information, signals, etc. input and/or output can be overwritten, updated or attached. Information, signals, etc., which are output data, can be removed. Information, signals, etc., which are input data, can be transferred to another machine.

The communication (notification) of information is in no way limited to the aspects/embodiments disclosed in the present invention, and other methods may also be used. For example, the communication of information in the present invention can be implemented using physical layer signaling (e.g., downlink control information (DCI), uplink control information (UCI)) higher layer signaling (e.g., RRC signaling (radio resource control). Control), broadcast information (main information block (MIB), system information blocks (SIBs), etc.), MAC signaling (media access control), etc.), and other signals, or combinations thereof.

Note that the physical layer signaling may be referred to as "Layer 1/Layer 2 (L1/L2) control information (L1/L2 control signals)", "L1 control information (L1 control signal)", etc. Also, the RRC signaling may be referred to as an "RRC message" and may be, for example, an RRC connection setup message, an RRC connection reconfiguration message, and so on. Also, MAC signaling can be signaled using, for example, MAC Control Elements (MAC CE).

Also, reporting certain information (eg, reporting "X holds") does not need to be done explicitly, but can be done implicitly (by, for example, not reporting that specific information or reporting another piece of information).

Decisions can be made in terms of a single bit (0 or 1), can be made in boolean values expressing true or false, or can be made by comparing numerical values (eg, comparing with a certain value).

Software referred to as "software", "firmware", "middleware", "microcode" or "hardware description language", or referred to by other terms, is to be construed broadly, to mean instructions, instruction sets, code, code segments, program codes, programs, subroutines, software modules, applications, application programs, software packages, algorithms, subalgorithms, objects, executables, execution threads, procedures, functions, etc.

Also, software, commands, information, etc. can be transmitted and received via the communication medium. For example, when software is transferred from a website, server, or other remote source using at least one of the wired technologies (coaxial cables, fiber optic cables, twisted pair cables, digital subscriber lines) etc.) and wireless technologies (infrared, microwaves, etc.), at least one of these wired technologies and wireless technologies are also included in the definition of the communication medium.

The terms "system" and "network" used in the present invention may be used interchangeably. "Network" may mean a device (eg, base station) included in the network.

In the present invention, terms such as "precoding", "precoder", "weight (precoding weight)", "quasi-local position (QCL)", "transmission configuration indication state (TCI state)", "spatial relation", " spatial domain filter", "transmit power", "phase rotation", "antenna port", "antenna port group", "level", "number of levels", "rank", "resource", "resource set", "group resources", "beam", "beam width", "beam angle", "antenna", "antenna element", "panel", etc. can be used interchangeably.

In the present invention, terms such as "base station (BS, from English base station)", "radio base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", " access point", "transmission point (TP, from the English transmission point)", "reception point (RP, from the English reception point)", "transmission / reception point (TRP, from the English transmission / reception point)", "panel", "cell", "sector", "cell group", "carrier", "component carrier", etc. may be used interchangeably. A base station may be referred to by terms such as "macro cell", "small cell", "femto cell", "pico cell", etc.

The base station can accommodate one or multiple (eg, three) cells. When the base station accommodates many cells, the entire coverage area of the base station can be divided into many small areas, and each small area can provide communication services through subsystems of the base station (for example, small base stations for indoor use (RRH, English Remote Radio Head, remote radio units)). The term "cell" or "sector" refers to part or all of the coverage area of at least one of a base station and a base station subsystem that provides communication services in that coverage area.

In the present invention, the terms "mobile station (MS, from English mobile station)", "user terminal", "user equipment (UE, from English user equipment)" and "terminal" can be used interchangeably.

A mobile station may in some cases be referred to as a "subscriber station", "mobile unit", "subscriber unit", "wireless unit", "remote unit", "mobile device", "wireless device", "wireless communication device", "remote device", "mobile subscriber station", "access terminal", "mobile terminal", "wireless terminal", "remote terminal", "portable telephone", "user agent", "mobile client", "client", or some other suitable terms.

The base station and/or the mobile station may be referred to as "transmitting apparatus", "receiving apparatus", "radio communication apparatus", etc. It should be noted that at least one of the base station and the mobile station may be a device mounted on a mobile unit, or the mobile unit itself, and so on. The movable object may be a vehicle (eg, a car, aircraft, etc.), may be an unmanned movable object (eg, an unmanned aerial vehicle, autonomous vehicle, etc.), or may be a robot (manned or unmanned). It should be noted that at least one of the base station and the mobile station also includes an apparatus that does not necessarily move during a communication operation. For example, at least one of the base station and the mobile station may be an Internet of Things (LOT) device such as a sensor or the like.

In addition, the base station in the present invention can be interpreted as a user terminal. For example, each aspect/embodiment of the present invention can be applied to a configuration in which communication between a base station and a user terminal is replaced by communication between a plurality of user terminals (which may be referred to as, for example, Device-to-Device (D2D). -Device), vehicle-all objects (V2X, from English vehicle-to-everything), etc.). In this case, the user terminals 20 may have the functions of the base stations 10 disclosed above. The words "uplink" and "downlink" can be interpreted as words corresponding to a terminal-to-terminal relationship (eg, "side"). For example, uplink, downlink, etc. may be interpreted as a side channel.

Similarly, the user terminal in the present invention may be interpreted as a base station. In this case, the base stations 10 may have the functions of the user terminal 20 described above.

The actions that have been disclosed in the present invention, to be performed by the base station, in some cases, can be performed by higher level nodes. Obviously, in a network containing one or more network nodes with base stations, various operations performed for communication with terminals can be performed by base stations, one or more network nodes (for example, MME nodes (from the English Mobility Management Entities , mobility management nodes), S-GWs (Serving-Gateways, serving gateways), etc., without limitation), other than base stations, or combinations thereof.

Aspects/embodiments illustrated in the present invention may be used alone or in combinations between which may be switched depending on the mode of implementation. The order of processes, sequences, flowcharts, etc. used to describe aspects/embodiments in the present invention may be changed as long as it does not cause conflict. For example, although various methods have been illustrated in the present invention with various components of the steps in sizing order, the specific orders illustrated in this application are in no way limiting.

Aspects/embodiments disclosed in the present invention can be applied to Long Term Evolution (LTE), LTE-Advanced (LTE-A), Super-LTE (LTE-B), SUPER 3G, IMT-Advanced, 4th generation (4G), 5th generation (5G) mobile communication system, future radio access system (FRA), new radio access technology (New-RAT), new radio access (NX), next generation radio access (FX), global system for mobile communications (GSM) , from the English Global System for Mobile communications) (registered trademark), CDMA2000, ultra-broadband mobile communications (UMB, from the English Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX ( registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable radio communication methods, next generation systems extensible based on the specified systems, and the like. A plurality of systems can be combined (eg, a combination of LTE or LTE-A and 5G, etc.) and applied.

The phrase "based on" (or "based on") used in the present invention does not mean "only based on" (or "only based on"), unless otherwise indicated. In other words, the phrase "based on" (or "based on") can mean both "based on only" and "based on at least" ("based on only" and "based on at least").

The reference to elements with designations such as "first", "second", etc. used in the present invention does not generally limit the number or order of these elements. These designations can be used in the present invention for convenience only, as a way to distinguish between two or more elements. Thus, the reference to the first and second elements does not imply that only two elements can be used, or that the first element must in some way precede the second element.

The terms "evaluate (determine)", as used in the present invention, can cover a wide range of activities. For example, "evaluate (determine)" can be understood in the sense of making "judgments (definitions)" in relation to judgment, calculation, calculation, processing, derivation, research, viewing, searching, and querying (for example, searching in a table, database, or some other data structures), clarifications, etc.

In addition, “evaluate (determine)” can be understood in the sense of making “judgments (definitions)” regarding reception (for example, receiving information), transmission (for example, transmitting information), input, output, organization of access (for example, access to data in memory), etc.

In addition, "evaluate (determine)" in the context of the present application can be understood in the sense of making "judgments (determinations)" regarding decision making, selection, selection, determination, comparison, etc. In other words, "evaluate (determine)" can be understood in the sense of making "judgments (determinations)" about some action.

In addition, "determining (making a decision)" can be interpreted as "guess", "expectation", "consideration", etc.

"Maximum transmit power" according to the present invention may mean a maximum transmit power value, may mean a nominal maximum transmit power (nominal maximum transmit power of a UE), or may mean a calculated maximum transmit power (estimated maximum transmit power of a UE).

In the context of the present invention, the terms "connected" and "connected" or any variation of these terms means a direct or indirect connection or connection between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "related" to each other. A connection or relationship between elements can be physical, logical, or combinations thereof. For example, "connection" can mean "access".

In the present invention, when two elements are connected, the two elements may be considered "connected" or "connected" to each other using one or more electrical wires, cables, and printed electrical connections, and, in some non-limiting and non-limiting examples, using electromagnetic energy. with wavelengths in the RF domain, microwave domain, and optical domain (both visible and invisible), or the like.

In the present invention, the phrase "A and B are different" may mean "A and B are different from each other." It should be noted that this phrase can mean "both A and B are different from C". The terms "separate", "be connected", etc. can be interpreted similarly to "different".

When terms such as "include", "including" and variants of these terms are used in the present invention, these terms should be inclusive, in the same way as if the term "comprising" were used. In addition, the term "or" in the context of the present invention should not carry the meaning of an exclusive disjunction.

For example, in the present invention, when articles such as "a", "an", and "the" are added in translation in English, the present invention may include that the noun following these articles is plural.

Although the invention in accordance with the present description has been disclosed in detail above, a person skilled in the art should be clear that the present invention is in no way limited to the embodiments disclosed in the present description. The invention according to the present disclosure may be implemented with various adjustments and in various modifications without deviating from the spirit and scope of the present invention as defined by the appended claims. Therefore, the description of the present invention is provided for the purpose of illustrating examples only and should not be construed as limiting the invention in accordance with the present description in any way.

Claims (18)

1. Terminal containing: a receiving section configured to receive a first configuration corresponding to one or more first search spaces and a second configuration corresponding to one or more second search spaces; and a control section, configured to determine one configuration from the first configuration and the second configuration based on downlink control information (DCI) format detection and physical downlink control channel (PDCCH) monitoring control according to a search space corresponding to said one configuration. 2. The terminal of claim 1, wherein the DCI format includes an indication of switching between one or more first search spaces and one or more second search spaces. 3. The terminal of claim 1, wherein the DCI format is provided to indicate the duration used to transmit the common spectrum. 4. A radio communication method for a terminal, including: receiving a first configuration corresponding to one or more first search spaces and a second configuration corresponding to one or more second search spaces; determining one configuration from the first configuration and the second configuration based on the Downlink Control Information (DCI) format detection; and monitoring the physical downlink control channel (PDCCH) in accordance with the search space corresponding to the specified one configuration. 5. Base station, containing: a transmission section configured to transmit a first configuration corresponding to one or more first search spaces and a second configuration corresponding to one or more second search spaces; and a control section configured to control the transmission of the Downlink Control Information (DCI) format used to determine one configuration from the first configuration and the second configuration, moreover, it is possible to monitor the physical downlink control channel (PDCCH) in accordance with the search space corresponding to the specified one configuration. 6. A radio communication system comprising a terminal and a base station in which terminal contains: a receiving section configured to receive a first configuration corresponding to one or more first search spaces and a second configuration corresponding to one or more second search spaces; and a control section configured to determine one configuration from the first configuration and the second configuration based on the detection of the downlink control information (DCI) format and monitoring control of the physical downlink control channel (PDCCH) according to a search space corresponding to said one configuration, and the base station is configured to transmit the first configuration and the second configuration and transmit the Downlink Control Information (DCI) format.

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