JP2018137801A - User terminal and base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve appropriate transmission of an uplink control signal even when the number of component carriers capable of being set at a user terminal is expanded.SOLUTION: The user terminal includes: a transmission unit for transmitting UL control information using an uplink control channel format in which a cyclic shift is applied to a reference signal for demodulation and an orthogonal code is applied with a sequence length of less than 5; a control unit for determining a cyclic shift applied to the reference signal for demodulation on the basis of a plurality of candidates set at uplink layer signaling and a field included in predetermined downlink control information.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a user terminal, a radio base station, and a radio communication method in a next generation mobile communication system.

  In the UMTS (Universal Mobile Telecommunications System) network, Long Term Evolution (LTE) has been specified for the purpose of higher data rate and low delay (Non-patent Document 1). LTE Rel. It is specified as 10-12.

  LTE Rel. The system band 10-12 includes at least one component carrier (CC) that uses the system band of the LTE system as a unit. In this manner, collecting a plurality of CCs to increase the bandwidth is referred to as carrier aggregation (CA).

  Also, Rel. In LTE of 8 to 12, the specification was performed on the assumption that exclusive operation is performed in a frequency band licensed by a business operator, that is, a license band. For example, 800 MHz, 2 GHz, or 1.7 GHz is used as the license band.

  Rel. In LTE 13 or later, operation in a license-free frequency band, that is, an unlicensed band is also considered as a target. As the unlicensed band, for example, the same 2.4 GHz or 5 GHz band as Wi-Fi is used. Rel. 13 LTE considers carrier aggregation (LAA: License-Assisted Access) between licensed and unlicensed bands, but may also be considered for dual connectivity and unlicensed band standalone in the future. There is.

3GPP TS 36.300 “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2”

  In CA in the LTE successor system (LTE Rel. 10-12) described above, the number of CCs that can be set per user terminal (UE) is limited to a maximum of five. LTE Rel., A further successor system of LTE. From 13 onwards, in order to realize more flexible and high-speed wireless communication, it has been studied to relax the limitation on the number of CCs that can be set in the user terminal and to set 6 or more CCs.

  However, when the number of CCs that can be set in the user terminal is expanded to 6 or more (for example, 32), it becomes difficult to apply the transmission method of the existing system (Rel. 10-12) as it is. For example, in an existing system, an uplink control signal (UCI: Uplink Control Information) such as a delivery confirmation signal (HARQ-ACK) for the DL signal of each CC is transmitted using an uplink control channel (PUCCH: Physical Uplink Control Channel). At this time, the user terminal transmits an uplink control signal by applying a PUCCH format based on 5 CC or less. On the other hand, when the user terminal transmits an uplink control signal of 6 CC or more, it is assumed that a new transmission method is required to appropriately transmit the uplink control signal.

  The present invention has been made in view of such a point, and even when the number of component carriers that can be set in a user terminal is expanded, a user terminal and a base station that can appropriately transmit an uplink control signal Is one of the purposes.

  One aspect of the user terminal of the present invention is a transmission for transmitting UL control information using an uplink control channel format in which a cyclic shift is applied to a demodulation reference signal and an orthogonal code is applied with a sequence length of less than 5 And a control unit that determines a cyclic shift to be applied to the demodulation reference signal based on a plurality of candidates set in higher layer signaling and a field included in predetermined downlink control information. It is characterized by.

  According to the present invention, it is possible to appropriately transmit an uplink control signal even when the number of component carriers that can be set in a user terminal is expanded.

LTE Rel. 13 is an explanatory diagram of a carrier carrier of carrier aggregation studied in FIG. In PUCCH format 3 / PUSCH, it is a figure which shows an example of the PUCCH format in case non-DMRS is made non-spread. It is a figure which shows an example of the PUCCH format which can support a capacity | capacitance rather than the existing PUCCH format. It is a figure which shows an example of the new PUCCH format which concerns on this Embodiment. It is a figure which shows an example of the table used for determination of the cyclic shift of DMRS of a new PUCCH format. It is a figure which shows the other example of the new PUCCH format which concerns on this Embodiment. It is a figure which shows the other example of the new PUCCH format which concerns on this Embodiment. It is a figure which shows an example of the table used for the cyclic shift of DMRS of a new PUCCH format, and determination of an orthogonal code. It is a schematic block diagram which shows an example of schematic structure of the radio | wireless communications system which concerns on this Embodiment. It is a figure which shows an example of the whole structure of the wireless base station which concerns on this Embodiment. It is a figure which shows an example of a function structure of the radio base station which concerns on this Embodiment. It is a figure which shows an example of the whole structure of the user terminal which concerns on this Embodiment. It is a figure which shows an example of a function structure of the user terminal which concerns on this Embodiment.

  FIG. 1 is an explanatory diagram of carrier aggregation (CA). As shown in FIG. In CA up to 12, LTE Rel. A maximum of five (CC # 1 to CC # 5) component carriers (CC) each having eight system bands as a unit are bundled. That is, LTE Rel. In the carrier aggregation up to 12, the number of CCs that can be set per user terminal (UE: User Equipment) is limited to a maximum of five.

  Meanwhile, LTE Rel. In the carrier aggregation after 13th, it is considered to further expand the bandwidth by bundling 6 or more CCs. That is, LTE Rel. In 13 carrier aggregation, it is considered to expand the number of CCs that can be set per user terminal to 6 or more (CA enhancement). For example, as shown in FIG. 1, when 32 CCs (CC # 1 to CC # 32) are bundled, it is possible to secure a maximum band of 640 MHz.

  As described above, it is expected to realize more flexible and high-speed wireless communication by expanding the number of CCs that can be set per user terminal. Further, such extension of the number of CCs is effective for widening the band by carrier aggregation (LAA: License-Assisted Access) between the license band and the unlicensed band. For example, when 5 CCs (= 100 MHz) of the license band and 15 CCs (= 300 MHz) of the unlicensed band are bundled, a 400 MHz band can be secured.

  In an unlicensed band in which LAA is operated, introduction of an interference control function is being studied in order to coexist with LTE, Wi-Fi or other systems of other operators. As an interference control function, LBT (Listen Before Talk) based on CCA (Clear Channel Assessment) has been studied. Therefore, the cell (CC) using the unlicensed band can be a cell to which listening (LBT or the like) is applied.

  On the other hand, when the number of CCs that can be set in the user terminal is expanded to 6 or more (for example, 32), the transmission method (for example, PUCCH format) of the existing system (Rel. 10-12) should be applied as it is. It becomes difficult.

  For example, in the existing system (Rel. 10-12), an uplink control signal such as an acknowledgment signal (HARQ-ACK) for DL data (PDSCH) transmitted in each CC is transmitted on the uplink control channel (PUCCH). At this time, the user terminal transmits an uplink control signal by applying a PUCCH format (for example, channel selection based on PUCCH format 1 / 1a, 1b, 3 or 1b) based on 5CC or less.

  For example, PUCCH format 3 that can transmit a large amount of uplink control information (for example, HARQ-ACK) in the existing PUCCH format supports up to 10 bits in FDD and 21 bits in TDD. FIG. 2 shows the configuration of the existing PUCCH format 3. The PUCCH format 3 is composed of two demodulation reference signals (DMRS) and five SC-FDMA (Single Carrier Frequency Divisional Multiple Access) symbols for each slot. The same bit string is mapped to each SC-FDMA symbol in each slot, but is multiplied by a spreading code (also referred to as orthogonal code or OCC) to multiplex a plurality of user terminals.

  In addition, cyclic shifts (also referred to as cyclic shifts or CSs) different among user terminals are applied to each DMRS in each slot. By applying orthogonal codes and cyclic shifts, it is possible to code division multiplex (CDM) up to five PUCCH formats 3 on the same resource (PRB). For example, HARQ bit strings can be orthogonally multiplexed using different OCC sequences for each user terminal, and DMRSs can be orthogonally multiplexed using different CS sequences for each user.

  However, when a user terminal transmits an uplink control signal of 6 CC or more (for example, 32 CC), it is assumed that a PUCCH format that supports 64-256 bits is required. For example, in FDD, when HARQ-ACK of 2 codewords (2 transport blocks) is transmitted every 32 CCs, it is 64 bits.

  In TDD, DL subframes (including special subframes) corresponding to one UL subframe are defined according to the UL / DL configuration to be applied. That is, in TDD, in 1 CC, HARQ-ACK with respect to DL signals of a plurality of DL subframes (for example, 4 subframes) may be transmitted in one UL subframe. For example, in TDD, when 2 codewords (2 transport blocks) HARQ-ACK is transmitted every 32 CCs and 4DL subframes correspond to one UL subframe, 256 bits (when spatial bundling is applied) 128 bits).

  Therefore, when the user terminal transmits an uplink control signal of 6 CC or more (for example, 32 CC), if the existing PUCCH format is used as it is, there is a possibility that the payload (capacity) of the PUCCH is insufficient and communication cannot be performed appropriately. Therefore, the present inventors support more bits (for example, 64-256 bits) than the existing PUCCH format in order to transmit uplink control signals for 6 or more CCs (for example, 32 CCs). The idea was to introduce uplink control transmission using a possible new PUCCH format.

  As a new PUCCH format capable of transmitting an uplink control signal (for example, HARQ-ACK) corresponding to six or more CCs, a configuration completely different from the existing PUCCH format can be considered. However, in this case, a new resource (PRB) needs to be allocated to the new PUCCH format, which causes a problem that the UL overhead of the entire system increases.

  Therefore, the present inventors have a configuration that has a larger capacity than the existing PUCCH format as a new PUCCH format, and can be multiplexed and transmitted on the same resource as an existing channel or signal (for example, PUCCH format and / or PUSCH). Inspired to do. In addition, the present inventors have found that a part of the configuration of the existing PUCCH format 3 and / or PUSCH is used to configure such a new PUCCH format.

  In the physical layer configuration of the existing PUCCH format 3, two reference signals (reference signal symbols) are set per slot. Therefore, when non-spreading QPSK modulation is applied to symbols that can be used for HARQ-ACK, a maximum of 240 bits (= 2 (bits) × 12 (subcarriers) × 10 (symbols) HARQ-ACK transmission is supported. (See FIG. 3A).

  Also, in the physical layer configuration of PUSCH, one reference signal (reference signal symbol) is set per slot. Therefore, when non-spread QPSK modulation is applied to symbols that can be used for HARQ-ACK, HARQ-ACK transmission of a maximum of 288 bits (= 2 (bits) × 12 (subcarriers) × 12 (symbols)) is supported. (See FIG. 3B).

  However, when a new PUCCH format is configured using the existing PUCCH format 3 or PUSCH, it is difficult to provide the UL control signal such as HARQ-ACK with a multiplexing capability equivalent to that of the existing PUCCH format. This is because in order to suppress the deterioration of communication quality, it is necessary to reduce the spreading factor by the amount that the PUCCH payload is increased.

  On the other hand, the present inventors applied MIMO division processing on the radio base station side by applying space division multiplexing to uplink control information (for example, HARQ-ACK) transmitted using symbols other than DMRS symbols. We focused on the fact that it can be separated using technology. In other words, when the radio base station side has spatial separation capability (the number of receiving antennas more than the number of spatially multiplexed user terminals), the DMRS can be separated by applying the DMRS to the DMRS. Focusing on the fact that uplink control signals can also be separated on the radio base station side by performing channel estimation for each user terminal and performing spatial separation signal processing similar to MIMO based on the obtained channel estimation results. Found PUCCH format.

  Specifically, the present inventors have adopted a configuration in which DMRS can be orthogonally multiplexed (CDM) with an existing PUCCH format and / or PUSCH as a new PUCCH format, and the capacity of signals to be allocated to symbols other than DMRS can be increased. Inspired to be larger than the format. For example, as a new PUCCH format, a cyclic shift and / or orthogonal code is applied to the first symbol for DMRS, and the orthogonal code is not applied to the second symbol other than DMRS, or a sequence less than a predetermined value It is possible to adopt a configuration in which an orthogonal code is applied with a long length. Here, the sequence length less than the predetermined value can be a sequence length less than the sequence length (for example, 5) applied in the existing PUCCH format 3.

  Hereinafter, this embodiment will be described in detail. In the following description, an example is described in which the number of CCs that can be set per user terminal in CA is 32, but the present invention is not limited to this. Moreover, although the case where a delivery confirmation signal (HARQ-ACK) is transmitted using symbols other than DMRS as a new PUCCH format is shown, it is not limited to this. For example, the new PUCCH format may be applied to transmission of other uplink control signals (channel state information (CSI) such as CQI, PMI, RI).

(First aspect)
In the first aspect, a new PUCCH format having DMRS capable of orthogonal multiplexing (CDM) with DMRS in an existing PUCCH format (for example, PUCCH format 3) will be described.

  An example of the physical layer configuration of the new PUCCH format in the first mode is shown in FIG. In the PUCCH format shown in FIG. 4, in each slot (first half slot and second half slot), two first symbols for DMRS are set, and five second symbols other than DMRS are set.

  In the new PUCCH format shown in FIG. 4, a cyclic shift is applied to the DMRS first symbol so that it can be orthogonally multiplexed with DMRS in the existing PUCCH format. Further, the orthogonal code is not applied to the second symbol other than the first symbol, or the orthogonal code is applied with a sequence length less than the sequence length (for example, 5) applied in the existing PUCCH format 3. As an example, UE1 multiplies the DMRS in the new PUCCH format by CS # 3, CS # 9, CS # 0, CS # 6, and UE2 multiplies CS # 0, CS # 6, CS # 3, CS # 9. By multiplying, DMRS can be orthogonally multiplexed between user terminals.

  The user terminal can apply DMRS expressed by the same mathematical expression as the existing PUCCH format 3 as DMRS of the new PUCCH format. Thus, even when a plurality of user terminals that transmit uplink control information using the existing PUCCH format 3 or the new PUCCH format are allocated to the same region (PRB), the radio base station performs channel estimation for each user terminal. The results can be separated. It is not always necessary to apply the same mathematical formula as PUCCH format 3.

  Also, the second symbol can multiplex a bit string of HARQ-ACK. Even when the user terminal transmits uplink control information without performing code multiplexing with the second symbol, the DMRS is CDM between the user terminals, and channel estimation for each user terminal can be performed appropriately. it can. Thereby, the radio base station can receive HARQ-ACK of different user terminals multiplexed on the same PRB spatially separated by using a plurality of reception antennas (MU-MIMO mechanism).

  In this way, by using the new PUCCH format shown in FIG. 4, it is possible to support transmission with a larger capacity than the existing PUCCH format and to apply the existing PUCCH format 3 allocation resource. Thereby, since it can be set as the structure which does not allocate a new resource (PRB) with respect to a new PUCCH format, the increase in UL overhead can be suppressed.

<CS applied to DMRS>
The user terminal can determine a cyclic shift index (CS index) to be applied to the DMRS in the new PUCCH format based on a predetermined condition. For example, the user terminal can determine the CS index to be applied to DMRS by applying the following equation (1).

  The ARI is identification information for designating a radio resource for the delivery confirmation signal. For example, the radio resource of the acknowledgment signal in the existing PUCCH format 3 can be determined by the user terminal based on the ARI field (ARI field) set in the downlink control information. When applying carrier aggregation using a primary cell and a secondary cell, the user terminal can read the field for TPC command included in the downlink control information (DL assignment) of the secondary cell as an ARI field. The user terminal can determine a radio resource to be used for the delivery confirmation signal by using a value specified in the ARI field from among a plurality of preset candidate values.

<Application of orthogonal code>
In a symbol (second symbol) in which DMRS is not arranged, an acknowledgment signal (HARQ-ACK bit string) can be transmitted. In this case, for the second symbol, an orthogonal code may not be applied and spreading itself may not be performed (see FIG. 6A), or spreading processing may be performed using an orthogonal code (OCC) having a sequence length of less than 5. May be performed (see FIG. 6B).

  As shown in FIG. 6A, when an orthogonal code is not applied to the second symbol, the number of PUCCHs that can be orthogonally multiplexed (CDM) to the same PRB is 1, and the number of bits that can be transmitted in the PUCCH format is 240 bits. The PUCCH format configuration shown in FIG. 6A is suitable when the number of bits of uplink control information (for example, HARQ-ACK) transmitted by the user terminal is large (for example, when the number of connected CCs is large or when TDD is applied). Can be applied to.

  FIG. 6B shows a case where an orthogonal code (spreading factor is 2.5) is applied to the second symbol. In this case, the number of PUCCHs that can be orthogonally multiplexed (CDM) to the same PRB is 2 (CDM is possible for 2 user terminals), and the number of bits that can be transmitted in the PUCCH format is 96 bits. The PUCCH format shown in FIG. 6B is suitable when the number of bits of uplink control information (for example, HARQ-ACK) transmitted by the user terminal is small (for example, when the number of connected CCs is a predetermined value or less and FDD is applied). Can be applied to. Note that the spreading factor when the orthogonal code is applied to the second symbol is not limited to 2.5.

  Further, the user terminal may switch between the PUCCH format in FIG. 6A and the PUCCH format in FIG. 6B based on a predetermined condition. As predetermined conditions, the number of CCs to be set, the number of CCs that transmit uplink control information, the number of bits of uplink control information, the presence / absence of application of spatial bundling, the number of codewords to be applied (number of transport blocks), One or any combination of FDD / TDD).

  In addition, the user terminal notifies the base station in advance of terminal capability information (UE capability) that either or both of the PUCCH format in FIG. 6A and the PUCCH format in FIG. 6B can be set. It is good. The terminal capability information may be signaling independent of the number of CCs capable of CA, or may be uniquely determined according to the number of CCs capable of CA. When uniquely determined according to the number of CCs, independent signaling can be made unnecessary.

  The resource (PRB number) used for transmission of the new PUCCH format can be set in advance in the user terminal by higher layer signaling. Or it is good also as a structure which sets several PRB (candidate PRB) with respect to a user terminal by upper layer signaling, and a user terminal selects predetermined PRB from candidate PRB based on ARI of downlink control information. In addition, when using ARI, the said ARI will designate the CS number applied to DMRS, and the information which determines the PRB number which transmits PUCCH.

(Second aspect)
In the second aspect, a new PUCCH format having DMRS capable of orthogonal multiplexing (CDM) with DMRS of existing PUSCH will be described.

  An example of the physical layer configuration of the new PUCCH format in the second mode is shown in FIG. In the new PUCCH format shown in FIG. 7, one first symbol for DMRS is set in one slot, and six second symbols other than DMRS are set.

  Further, in the new PUCCH format shown in FIG. 7, cyclic shift and / or orthogonal code (OCC) is applied to the first DMRS symbol so as to be orthogonally multiplexed with DMRS of PUSCH. Further, the orthogonal code is not applied to the second symbol other than the DMRS symbol, or the orthogonal code is applied with a sequence length less than a predetermined sequence length. For example, the DMRS in the new PUCCH format can be orthogonally multiplexed between user terminals by UE1 multiplying by orthogonal code [+1 -1] and UE2 by multiplying by orthogonal code [+1 +1].

  The user terminal can apply DMRS expressed by the same mathematical expression as PUSCH as DMRS in the new PUCCH format. Thereby, even when a user terminal that transmits uplink control information using a new PUCCH format and a user terminal that transmits uplink data (PUSCH) using PUSCH use the same region (PRB), The radio base station can separate channel estimation results for each user terminal. Of course, even when a plurality of user terminals that transmit uplink control information using the new PUCCH format are assigned to the same region (PRB), the radio base station can separate the channel estimation results of each user terminal. It is not always necessary to apply the same mathematical formula as PUSCH.

  Also, the second symbol can multiplex a bit string of HARQ-ACK. When the user terminal transmits uplink control information without performing code multiplexing on the second symbol, based on space division (MU-MIMO mechanism) by using a plurality of reception antennas on the radio base station side It can be received spatially separated.

  In this way, by using the new PUCCH format shown in FIG. 7, it is possible to support transmission with a larger capacity than the existing PUCCH format and to apply PUSCH allocation resources. Thereby, since it can be set as the structure which does not allocate a new resource (PRB) with respect to a new PUCCH format, the increase in UL overhead can be suppressed.

<CS / OCC applied to DMRS>
The user terminal can determine a cyclic shift index (CS index) and / or an orthogonal sequence (OCC) to be applied to DMRS of the new PUCCH format based on a predetermined condition. For example, the user terminal can determine the CS index to be applied to DMRS by applying the following equation (3).

  As a value notified by higher layer signaling, a value set by higher layer signaling different from PUSCH may be used, or a value of higher layer signaling set for PUSCH may be used. When using higher layer signaling for PUSCH for the new PUCCH format, signaling overhead can be reduced. In addition, when higher layer signaling different from PUSCH is used for a new PUCCH format, for example, although CS index setting is independent of PUSCH of a connected cell, CS common to PUSCH of other cells (for example, neighboring cells) Flexible control such as setting an index is possible.

  When higher layer signaling set for PUSCH is applied, for example, physical cell ID (VCID) set for determining a DMSCH sequence of PUSCH, information on setting of inter-slot hopping (Group-hopping-enabled, Disable) -sequence-group-hopping), and information (Activate-DMRS-with OCC) regarding the setting of applicability of OCC can be applied to DMRS in the new PUCCH format.

  Also, the user terminal can determine an orthogonal code (OCC) from a predetermined table based on bit information (index) notified from the radio base station (see FIG. 8). For example, the user terminal can determine a predetermined orthogonal sequence based on bit information specified by a CS / OCC identifier (CS / OCC indicator) included in downlink control information, similarly to PUSCH DMRS. The bit information specified by the CS / OCC identifier can also be used for determining the cyclic shift index.

  However, since the CS / OCC identifier used in the DMSCH of the PUSCH is included in the UL grant, it is difficult to apply it directly to the DMRS of the new PUCCH. Therefore, in the present embodiment, for DMRS of a new PUCCH format, a bit field (Cyclic shift for DM RS and OCC index) that is the same as an existing CS / OCC identifier or corresponding to an existing CS / OCC identifier is converted into PDCCH or You may set to the DL assignment transmitted by EPDCCH. In this case, the user terminal calculates the bit length assuming that the DL assignment includes the CS / OCC identifier, and performs reception processing (for example, blind detection) assuming the bit length.

  The CS / OCC identifier for DMRS of the new PUCCH format set in the DL assignment can be 3 bits, similar to the CS / OCC identifier for DMRS of the PUSCH set in the UL grant. Alternatively, the bit field for setting the CS / OCC identifier for DMRS in the new PUCCH format may be a bit field larger than 3 bits or a bit field smaller than 3 bits. When setting with less than 3 bits, a table configured by extracting some bit information from the table of FIG. 8 can be used.

  Alternatively, in the case of setting with less than 3 bits, a plurality of CS / OCC identifier candidates are set in the user terminal in advance by higher layer signaling, and a predetermined CS / OCC identifier is selected by the CS / OCC identifier of DL assignment. Good. Thereby, even when the number of bits set in the DL assignment is small, the CS / OCC identifier can be flexibly controlled.

  Alternatively, the user terminal using the new PUCCH format may determine a CS / OCC index to be applied to the DMRS of the new PUCCH format using a 2-bit TPC command included in the DL assignment of the secondary cell. In this case, the user terminal interprets a 2-bit TPC command included in the DL assignment of the secondary cell as an ARI. The user terminal can determine a specific CS / OCC index from a plurality of CS / OCC identifier candidates set in advance by higher layer signaling or a predetermined table based on the index specified by the ARI. Moreover, a radio base station is good also as a structure which designates using PR for PRB which performs new PUCCH format transmission with respect to a user terminal.

(Configuration of wireless communication system)
Hereinafter, the configuration of a wireless communication system according to an embodiment of the present invention will be described. In this wireless communication system, the wireless communication method according to the embodiment of the present invention is applied. In addition, the radio | wireless communication method which concerns on said each aspect may be applied independently, respectively, and may be applied in combination.

  FIG. 9 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment of the present invention. Note that the radio communication system shown in FIG. 9 is a system including, for example, an LTE system, SUPER 3G, LTE-A system, and the like. In this wireless communication system, carrier aggregation (CA) and / or dual connectivity (DC) in which a plurality of basic frequency blocks (component carriers) having the system bandwidth of the LTE system as one unit can be applied. In addition, this radio | wireless communications system may be called IMT-Advanced, and may be called 4G, 5G, FRA (Future Radio Access), etc.

  The radio communication system 1 shown in FIG. 9 includes a radio base station 11 that forms a macro cell C1, and radio base stations 12a-12c that are arranged in the macro cell C1 and form a small cell C2 that is narrower than the macro cell C1. . Moreover, the user terminal 20 is arrange | positioned at the macrocell C1 and each small cell C2.

  The user terminal 20 can be connected to both the radio base station 11 and the radio base station 12. It is assumed that the user terminal 20 uses the macro cell C1 and the small cell C2 that use different frequencies simultaneously by CA or DC. Further, the user terminal 20 can apply CA or DC using at least six or more CCs (cells).

  Communication between the user terminal 20 and the radio base station 11 can be performed using a carrier having a relatively low frequency band (for example, 2 GHz) and a narrow bandwidth (referred to as an existing carrier or a legacy carrier). On the other hand, a carrier having a relatively high frequency band (for example, 3.5 GHz, 5 GHz, etc.) and a wide bandwidth may be used between the user terminal 20 and the radio base station 12, or The same carrier may be used. Between the wireless base station 11 and the wireless base station 12 (or between the two wireless base stations 12), a wired connection (optical fiber, X2 interface, etc.) or a wireless connection may be employed.

  The radio base station 11 and each radio base station 12 are connected to the upper station apparatus 30 and connected to the core network 40 via the upper station apparatus 30. The upper station device 30 includes, for example, an access gateway device, a radio network controller (RNC), a mobility management entity (MME), and the like, but is not limited thereto. Each radio base station 12 may be connected to the higher station apparatus 30 via the radio base station 11.

  The radio base station 11 is a radio base station having a relatively wide coverage, and may be called a macro base station, an aggregation node, an eNB (eNodeB), a transmission / reception point, or the like. The radio base station 12 is a radio base station having local coverage, and is a small base station, micro base station, pico base station, femto base station, HeNB (Home eNodeB), RRH (Remote Radio Head), transmission / reception. It may be called a point. Hereinafter, when the radio base stations 11 and 12 are not distinguished, they are collectively referred to as a radio base station 10. Each user terminal 20 is a terminal that supports various communication schemes such as LTE and LTE-A, and may include not only mobile communication terminals but also fixed communication terminals.

  In a radio communication system, OFDMA (Orthogonal Frequency Division Multiple Access) is applied to the downlink and SC-FDMA (Single Carrier Frequency Division Multiple Access) is applied to the uplink as radio access schemes. OFDMA is a multi-carrier transmission scheme that performs communication by dividing a frequency band into a plurality of narrow frequency bands (subcarriers) and mapping data to each subcarrier. SC-FDMA is a single-carrier transmission scheme that reduces interference between terminals by dividing the system bandwidth into bands composed of one or continuous resource blocks for each terminal, and a plurality of terminals using different bands. is there. The uplink and downlink radio access methods are not limited to these combinations.

  In the wireless communication system 1, downlink channels include a downlink shared channel (PDSCH) shared by each user terminal 20, a broadcast channel (PBCH: Physical Broadcast Channel), a downlink L1 / L2 control channel, and the like. Used. User data, higher layer control information, and predetermined SIB (System Information Block) are transmitted by the PDSCH. Moreover, MIB (Master Information Block) etc. are transmitted by PBCH.

  Downlink L1 / L2 control channels include PDCCH (Physical Downlink Control Channel), EPDCCH (Enhanced Physical Downlink Control Channel), PCFICH (Physical Control Format Indicator Channel), PHICH (Physical Hybrid-ARQ Indicator Channel), and the like. Downlink control information (DCI) including scheduling information of PDSCH and PUSCH is transmitted by PDCCH. The number of OFDM symbols used for PDCCH is transmitted by PCFICH. The HAICH transmission confirmation signal (ACK / NACK) for PUSCH is transmitted by PHICH. The EPDCCH is frequency division multiplexed with a PDSCH (downlink shared data channel) and may be used to transmit DCI or the like in the same manner as the PDCCH.

  In the wireless communication system 1, as an uplink channel, an uplink shared channel (PUSCH) shared by each user terminal 20, an uplink control channel (PUCCH), a random access channel (PRACH: PRACH). Physical Random Access Channel) is used. User data and higher layer control information are transmitted by PUSCH. Also, downlink radio quality information (CQI: Channel Quality Indicator), a delivery confirmation signal (HQRQ-ACK), and the like are transmitted by PUCCH. A random access preamble (RA preamble) for establishing a connection with the cell is transmitted by the PRACH.

<Wireless base station>
FIG. 10 is a diagram illustrating an example of the overall configuration of a radio base station according to an embodiment of the present invention. The radio base station 10 includes a plurality of transmission / reception antennas 101, an amplifier unit 102, a transmission / reception unit 103, a baseband signal processing unit 104, a call processing unit 105, and a transmission path interface 106. Note that the transmission / reception unit 103 includes a transmission unit and a reception unit.

  User data transmitted from the radio base station 10 to the user terminal 20 via the downlink is input from the higher station apparatus 30 to the baseband signal processing unit 104 via the transmission path interface 106.

  In the baseband signal processing unit 104, for user data, PDCP (Packet Data Convergence Protocol) layer processing, user data division / combination, RLC (Radio Link Control) retransmission control and other RLC layer transmission processing, MAC (Medium Access) Control) Retransmission control (for example, transmission processing of HARQ (Hybrid Automatic Repeat reQuest)), scheduling, transmission format selection, channel coding, inverse fast Fourier transform (IFFT) processing, transmission processing such as precoding processing, etc. Is transferred to each transceiver 103. The downlink control signal is also subjected to transmission processing such as channel coding and inverse fast Fourier transform, and transferred to each transmitting / receiving unit 103.

  Each transmission / reception unit 103 converts the baseband signal output by precoding from the baseband signal processing unit 104 for each antenna to a radio frequency band and transmits the converted signal. The radio frequency signal frequency-converted by the transmission / reception unit 103 is amplified by the amplifier unit 102 and transmitted from the transmission / reception antenna 101.

  For example, the transmission / reception unit 103 can transmit information (information such as frequency and / or number of CCs) related to a CC performing CA. In addition, the transmission / reception unit 103 receives Rel. The information on the UCI transmission method (for example, new PUCCH format) applied after 13 and information on the PUCCH resource used when applying a predetermined PUCCH format can be transmitted. The transmission / reception unit 103 can be a transmitter / receiver, a transmission / reception circuit, or a transmission / reception device described based on common recognition in the technical field according to the present invention.

  On the other hand, for the uplink signal, the radio frequency signal received by each transmission / reception antenna 101 is amplified by the amplifier unit 102. Each transmitting / receiving unit 103 receives the upstream signal amplified by the amplifier unit 102. In addition, the transmission / reception section 103 uses the transmission / reception antennas 101 equal to or more than the number of user terminals to be spatially multiplexed, and uses uplink control signals (HARQ-ACK, etc.) and / or uplink data (such as HARQ-ACK) multiplexed on the same PRB using a new PUCCH format. (PUSCH) can be received spatially separated. The transmission / reception unit 103 converts the frequency of the received signal into a baseband signal and outputs it to the baseband signal processing unit 104.

  The baseband signal processing unit 104 performs Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing, and error correction on user data included in the input upstream signal. Decoding, MAC retransmission control reception processing, RLC layer, and PDCP layer reception processing are performed and transferred to the upper station apparatus 30 via the transmission path interface 106. The call processing unit 105 performs call processing such as communication channel setting and release, status management of the radio base station 10, and radio resource management.

  The transmission path interface 106 transmits and receives signals to and from the higher station apparatus 30 via a predetermined interface. The transmission path interface 106 may transmit and receive signals (backhaul signaling) to and from the adjacent radio base station 10 via an inter-base station interface (for example, an optical fiber or an X2 interface).

  FIG. 11 is a diagram illustrating an example of a functional configuration of the radio base station according to the present embodiment. Note that FIG. 11 mainly shows functional blocks of characteristic portions in the present embodiment, and the wireless base station 10 also has other functional blocks necessary for wireless communication. As illustrated in FIG. 11, the baseband signal processing unit 104 includes a control unit (scheduler) 301, a transmission signal generation unit (generation unit) 302, a mapping unit 303, and a reception signal processing unit 304. .

  The control unit (scheduler) 301 controls scheduling (for example, resource allocation) of downlink data signals transmitted on PDSCH and downlink control signals transmitted on PDCCH and / or EPDCCH. Further, scheduling control such as system information, synchronization signal, paging information, CRS (Cell-specific Reference Signal), CSI-RS (Channel State Information Reference Signal) is also performed. It also controls scheduling of uplink reference signals, uplink data signals transmitted on PUSCH, uplink control signals transmitted on PUCCH and / or PUSCH, random access preambles transmitted on PRACH, and the like.

  The control unit 301 controls retransmission of downlink data based on a delivery confirmation signal (HARQ-ACK) fed back from the user terminal. The control unit 301 may be a controller, a control circuit, or a control device described based on common recognition in the technical field according to the present invention.

  The transmission signal generation unit 302 generates a DL signal based on an instruction from the control unit 301 and outputs the DL signal to the mapping unit 303. For example, based on an instruction from the control unit 301, the transmission signal generation unit 302 generates a DL assignment that notifies downlink signal allocation information and a UL grant that notifies uplink signal allocation information. Further, the downlink data signal is subjected to coding processing and modulation processing according to a coding rate, a modulation scheme, and the like determined based on channel state information (CSI) from each user terminal 20.

  The transmission signal generation unit 302 can generate information on a CS index and / or an orthogonal sequence (OCC) that the user terminal applies to the DMRS in the new PUCCH format. For example, the transmission signal generation unit 302 generates downlink control information (UL grant and / or DL assignment) including information on ARI and information on CS / OCC identifier (CS / OCC indicator).

  The transmission signal generation unit 302 can be a signal generator, a signal generation circuit, or a signal generation device described based on common recognition in the technical field according to the present invention.

  Based on an instruction from the control unit 301, the mapping unit 303 maps the downlink signal generated by the transmission signal generation unit 302 to a predetermined radio resource, and outputs it to the transmission / reception unit 103. Note that the mapping unit 303 can be a mapper, a mapping circuit, or a mapping device described based on common recognition in the technical field according to the present invention.

  The reception signal processing unit 304 receives UL signals (for example, a delivery confirmation signal (HARQ-ACK), a data signal transmitted by PUSCH, a random access preamble transmitted by PRACH, etc.) transmitted from the user terminal. Processing (for example, demapping, demodulation, decoding, etc.) is performed. The processing result is output to the control unit 301.

  The received signal processing unit 304 may measure received power (for example, RSRP (Reference Signal Received Power)), received quality (RSRQ (Reference Signal Received Quality)), channel state, and the like using the received signal. . The measurement result may be output to the control unit 301.

  The reception signal processing unit 304 may be configured by a signal processor, a signal processing circuit or a signal processing device, and a measuring device, a measurement circuit or a measuring device, which are described based on common recognition in the technical field according to the present invention. it can.

<User terminal>
FIG. 12 is a diagram illustrating an example of the overall configuration of the user terminal according to the present embodiment. The user terminal 20 includes a plurality of transmission / reception antennas 201 for MIMO transmission, an amplifier unit 202, a transmission / reception unit 203, a baseband signal processing unit 204, and an application unit 205. Note that the transmission / reception unit 203 may include a transmission unit and a reception unit.

  Radio frequency signals received by the plurality of transmission / reception antennas 201 are each amplified by the amplifier unit 202. Each transmitting / receiving unit 203 receives the downlink signal amplified by the amplifier unit 202. The transmission / reception unit 203 converts the frequency of the received signal into a baseband signal and outputs it to the baseband signal processing unit 204.

  The transmission / reception unit 203 transmits a UL control signal (PUCCH) including a delivery confirmation signal for a DL signal (for example, PDSCH). In addition, the transmission / reception unit 203 can receive information on a CS index and / or an orthogonal code (OCC) applied to a DMRS in a new PUCCH format. Further, the transmission / reception unit 203 can receive information related to the allocation resource of the UL control signal to be transmitted by applying the new PUCCH format. The transmission / reception unit 203 can be a transmitter / receiver, a transmission / reception circuit, or a transmission / reception device described based on common recognition in the technical field according to the present invention.

  The baseband signal processing unit 204 performs FFT processing, error correction decoding, retransmission control reception processing, and the like on the input baseband signal. The downlink user data is transferred to the application unit 205. The application unit 205 performs processing related to layers higher than the physical layer and the MAC layer. In addition, broadcast information in the downlink data is also transferred to the application unit 205.

  On the other hand, uplink user data is input from the application unit 205 to the baseband signal processing unit 204. The baseband signal processing unit 204 performs retransmission control transmission processing (for example, HARQ transmission processing), channel coding, precoding, discrete Fourier transform (DFT) processing, IFFT processing, and the like. The data is transferred to the transmission / reception unit 203. The transmission / reception unit 203 converts the baseband signal output from the baseband signal processing unit 204 into a radio frequency band and transmits it. The radio frequency signal frequency-converted by the transmission / reception unit 203 is amplified by the amplifier unit 202 and transmitted from the transmission / reception antenna 201.

  FIG. 13 is a diagram illustrating an example of a functional configuration of the user terminal according to the present embodiment. Note that FIG. 13 mainly shows functional blocks of characteristic portions in the present embodiment, and the user terminal 20 also has other functional blocks necessary for wireless communication. As illustrated in FIG. 13, the baseband signal processing unit 204 included in the user terminal 20 includes a control unit 401, a transmission signal generation unit 402, a mapping unit 403, a reception signal processing unit 404, and a determination unit 405. I have.

  The control unit 401 obtains, from the reception signal processing unit 404, a downlink control signal (signal transmitted by PDCCH / EPDCCH) and a downlink data signal (signal transmitted by PDSCH) transmitted from the radio base station 10. The control unit 401 generates an uplink control signal (for example, an acknowledgment signal (HARQ-ACK)) or an uplink data signal based on a downlink control signal, a result of determining whether retransmission control is necessary for the downlink data signal, or the like. To control. Specifically, the control unit 401 can control the transmission signal generation unit 402, the mapping unit 403, and the reception signal processing unit 404.

  For example, the control unit 401 controls a format applied to transmission of a UL control signal (for example, HARQ-ACK). In addition, the control unit 401 can apply a new format having a larger capacity than the PUCCH format of the existing system to the UL control signal according to the number of CCs set.

  For example, the control unit 401 applies a cyclic shift and / or orthogonal code to the first symbol for DMRS, and does not apply the orthogonal code to the second symbol or applies it in the existing PUCCH format 3 The UL control signal can be transmitted using a new PUCCH format in which an orthogonal code is applied with a sequence length less than the sequence length.

  The control unit 401 can apply a cyclic shift so that the DMRS in the new PUCCH format can be orthogonal to the DMRS in the existing PUCCH format 3. For example, the control unit 401 can determine the DMRS cyclic shift value of the new PUCCH format using the PUCCH resource number specified by the ARI.

  When transmitting a UL control signal using the new PUCCH format, the control unit 401 uses the PRB number notified by higher layer signaling or the PRB number designated based on the ARI from the candidate PRB notified by higher layer signaling. Can be applied.

  The control unit 401 can apply a cyclic shift and / or an orthogonal code so that the DMRS of the new PUCCH format can be orthogonal to the DMRS of the existing uplink shared channel (PUSCH). The control unit 401 can determine the DMRS cyclic shift value and / or orthogonal code of the new PUCCH format based on the index included in the DL assignment. Or the control part 401 can interpret the TPC command contained in the DL assignment of a secondary cell as ARI, and can determine the cyclic shift value and / or orthogonal code of DMRS of a new PUCCH format.

  The control unit 401 may be a controller, a control circuit, or a control device described based on common recognition in the technical field according to the present invention.

  The transmission signal generation unit 402 generates a UL signal based on an instruction from the control unit 401 and outputs the UL signal to the mapping unit 403. For example, the transmission signal generation unit 402 generates an uplink control signal such as a delivery confirmation signal (HARQ-ACK) or channel state information (CSI) based on an instruction from the control unit 401.

  In addition, the transmission signal generation unit 402 generates an uplink data signal based on an instruction from the control unit 401. For example, the transmission signal generation unit 402 is instructed by the control unit 401 to generate an uplink data signal when the UL grant is included in the downlink control signal notified from the radio base station 10. The transmission signal generation unit 402 may be a signal generator, a signal generation circuit, or a signal generation device described based on common recognition in the technical field according to the present invention.

  The mapping unit 403 maps the uplink signal (uplink control signal and / or uplink data) generated by the transmission signal generation unit 402 to a radio resource based on an instruction from the control unit 401, and outputs the radio resource to the transmission / reception unit 203. . The mapping unit 403 may be a mapper, a mapping circuit, or a mapping device described based on common recognition in the technical field according to the present invention.

  The reception signal processing unit 404 performs reception processing (for example, demapping, demodulation, decoding, etc.) on the DL signal (for example, downlink control signal transmitted from the radio base station, downlink data signal transmitted by PDSCH, etc.). I do. The reception signal processing unit 404 outputs information received from the radio base station 10 to the control unit 401 and the determination unit 405. The reception signal processing unit 404 outputs broadcast information, system information, RRC signaling, DCI, and the like to the control unit 401, for example.

  The reception signal processing unit 404 may be configured by a signal processor, a signal processing circuit or a signal processing device, and a measuring device, a measurement circuit or a measuring device which are described based on common recognition in the technical field according to the present invention. it can. Further, the reception signal processing unit 404 can constitute a reception unit according to the present invention.

  The determination unit 405 performs retransmission control determination (ACK / NACK) based on the decoding result of the received signal processing unit 404 and outputs the determination result to the control unit 401. When a downlink signal (PDSCH) is transmitted from a plurality of CCs (for example, 6 or more CCs), retransmission control determination (ACK / NACK) is performed for each CC and output to the control unit 401. The determination part 405 can be comprised from the determination circuit or determination apparatus demonstrated based on common recognition in the technical field which concerns on this invention.

  In addition, the block diagram used for description of the said embodiment has shown the block of the functional unit. These functional blocks (components) are realized by any combination of hardware and software. Further, the means for realizing each functional block is not particularly limited. That is, each functional block may be realized by one physically coupled device, or may be realized by two or more physically separated devices connected by wire or wirelessly and by a plurality of these devices. Good.

  For example, some or all of the functions of the radio base station 10 and the user terminal 20 are realized using hardware such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA). May be. The radio base station 10 or the user terminal 20 is a computer device including a processor (CPU: Central Processing Unit), a communication interface for network connection, a memory, and a computer-readable storage medium holding a program. It may be realized. That is, the radio base station, user terminal, and the like according to an embodiment of the present invention may function as a computer that performs processing of the radio communication method according to the present invention.

  Here, the processor, the memory, and the like are connected by a bus for communicating information. The computer-readable recording medium includes, for example, a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), a CD-ROM (Compact Disc-ROM), a RAM (Random Access Memory), A storage medium such as a hard disk. In addition, the program may be transmitted from a network via a telecommunication line. The radio base station 10 and the user terminal 20 may include an input device such as an input key and an output device such as a display.

  The functional configurations of the radio base station 10 and the user terminal 20 may be realized by the hardware described above, may be realized by a software module executed by a processor, or may be realized by a combination of both. The processor controls the entire user terminal by operating an operating system. Further, the processor reads programs, software modules and data from the storage medium into the memory, and executes various processes according to these.

  Here, the program may be a program that causes a computer to execute the operations described in the above embodiments. For example, the control unit 401 of the user terminal 20 may be realized by a control program stored in a memory and operated by a processor, and may be realized similarly for other functional blocks.

  Also, software, instructions, etc. may be transmitted / received via a transmission medium. For example, software may use websites, servers, or other devices using wired technology such as coaxial cable, fiber optic cable, twisted pair and digital subscriber line (DSL) and / or wireless technology such as infrared, wireless and microwave. When transmitted from a remote source, these wired and / or wireless technologies are included within the definition of transmission media.

  In addition, about each term demonstrated in this specification and / or required for an understanding of this specification, you may replace with the term which has the same or similar meaning. For example, the radio resource may be indicated by an index. Further, the channel and / or symbol may be a signal (signaling). The signal may be a message. Further, the component carrier (CC) may be called a carrier frequency, a cell, or the like.

  Each aspect / embodiment shown in this specification may be used independently, may be used in combination, and may be used by switching according to execution. In addition, notification of predetermined information (for example, notification of being “X”) is not limited to explicitly performed, but is performed implicitly (for example, notification of the predetermined information is not performed). Also good.

  The notification of information is not limited to the aspect / embodiment shown in this specification, and may be performed by other methods. For example, information notification includes physical layer signaling (for example, DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (for example, RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling), It may be implemented by broadcast information (MIB (Master Information Block), SIB (System Information Block))), other signals, or a combination thereof. Further, the RRC signaling may be, for example, an RRC connection setup (RRCConnectionSetup) message, an RRC connection reconfiguration (RRCConnectionReconfiguration) message, or the like.

  Information, signals, etc. presented herein may be represented using any of a variety of different technologies. For example, data, commands, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of these May be represented by a combination of

  Each aspect / embodiment shown in this specification includes LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G, 5G, Future Radio Access (FRA), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), and other suitable systems The present invention may be applied to a system and / or a next-generation system extended based on these systems.

  As long as there is no contradiction, the order of the processing procedures, sequences, flowcharts, and the like of each aspect / embodiment shown in this specification may be changed. For example, the methods presented herein present the elements of the various steps in an exemplary order and are not limited to the specific order presented.

  Although the present invention has been described in detail above, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

DESCRIPTION OF SYMBOLS 1 Wireless communication system 10 Wireless base station 20 User terminal 101 Transmission / reception antenna 102 Amplifier part 103 Transmission / reception part 104 Baseband signal processing part 105 Call processing part 106 Transmission path interface 201 Transmission / reception antenna 202 Amplifier part 203 Transmission / reception part 204 Baseband signal processing part 205 Application unit 301, 401 Control unit 302, 402 Transmission signal generation unit 303, 403 Mapping unit 304, 404 Reception signal processing unit 405 Determination unit

Claims (3)

A transmitter that transmits UL control information using an uplink control channel format in which a cyclic shift is applied to a demodulation reference signal and an orthogonal code is applied with a sequence length of less than 5;
A control unit that determines a cyclic shift to be applied to the demodulation reference signal based on a plurality of candidates set in higher layer signaling and a field included in predetermined downlink control information, User terminal.   The user terminal according to claim 1, wherein the UL control information includes at least HARQ-ACK. A receiver for receiving UL control information transmitted using an uplink control channel format in which a cyclic shift is applied to a demodulation reference signal and an orthogonal code is applied with a sequence length of less than 5;
Control for controlling transmission of downlink control information including a field for designating a predetermined candidate while transmitting a plurality of candidates used for determining a cyclic shift to be applied to the demodulation reference signal using higher layer signaling And a base station.

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