WO2011118167A1

WO2011118167A1 - Terminal apparatus, base station apparatus and signal transmission control method

Info

Publication number: WO2011118167A1
Application number: PCT/JP2011/001591
Authority: WO
Inventors: 中尾正悟
Original assignee: パナソニック株式会社
Priority date: 2010-03-26
Filing date: 2011-03-17
Publication date: 2011-09-29

Abstract

Disclosed are a terminal apparatus, a base station apparatus and a signal transmission control method whereby in a communication system to which a carrier aggregation using a plurality of downstream unit bands is applied, when SR, which requests a resource allocation used for upstream channel data transmission, and bulk response signals occur in the same subframe, the transmission qualities of the bulk response signals can be secured. In a terminal (200), a control unit (208) places a reference signal on a reference signal resource on the basis of the occurrence status of bulk ACK/NACK signals and the SR, which requests a resource allocation used for upstream channel data transmission, in the same subframe (transmission unit time). Specifically, when only the bulk ACK/NACK signals occur in the same subframe, the control unit (208) places reference signals for the bulk ACK/NACK signals onto a first reference signal resource. When the SR and the bulk ACK/NACK signals occur in the same subframe, the control unit (208) places the reference signals for the bulk ACK/NACK signals onto a second reference signal resource different from the first reference signal resource.

Description

Terminal apparatus, base station apparatus, and signal transmission control method

The present invention relates to a terminal device, a base station device, and a signal transmission control method.

In 3GPP LTE, OFDMA (Orthogonal Frequency Division Multiple Access) is adopted as a downlink communication method. In a wireless communication system to which 3GPP LTE is applied, a base station device (hereinafter abbreviated as “base station”) uses a predetermined communication resource to synchronize (Synchronization Channel: SCH) and broadcast signal (Broadcast Channel: BCH). ). A terminal device (hereinafter abbreviated as “terminal”) first secures synchronization with the base station by capturing the SCH. After that, the terminal acquires parameters (for example, frequency bandwidth) unique to the base station by reading the BCH information (see Non-Patent

Documents

1, 2, and 3).

The terminal establishes communication with the base station by making a connection request to the base station after the acquisition of the parameters unique to the base station is completed. The base station transmits control information via a PDCCH (Physical 確立 Downlink Control CHannel) as necessary to a terminal with which communication has been established.

Then, the terminal performs “blind determination” for each of the plurality of control information included in the received PDCCH signal. That is, the control information includes a CRC (Cyclic Redundancy Check) part, and this CRC part is masked by the terminal ID of the transmission target terminal in the base station. Therefore, the terminal cannot determine whether or not the received control information is control information destined for the own apparatus until the CRC portion of the received control information is demasked with the terminal ID of the own apparatus. In this blind determination, if the CRC calculation is OK as a result of demasking, it is determined that the control information is addressed to the own apparatus.

In 3GPP LTE, ARQ (Automatic Repeat Request) is applied to downlink data from the base station to the terminal. That is, the terminal feeds back a response signal indicating an error detection result of downlink data to the base station. The terminal performs CRC on the downlink data, and if CRC = OK (no error), ACK (Acknowledgment) is sent to the base station as a response signal, and if CRC = NG (error is found), NACK (Negative Acknowledgment) is sent to the base station as a response signal. provide feedback. However, BPSK (Binary Phase Shift Shift Keying) is used to modulate the response signal (that is, ACK / NACK signal). Further, an uplink control channel such as PUCCH (Physical-Uplink-Control-Channel) is used for feedback of the response signal. If the received response signal indicates NACK, the base station transmits retransmission data to the terminal.

Here, the control information (that is, downlink allocation control information) transmitted from the base station includes resource allocation information including resource information allocated to the terminal by the base station. As described above, the PDCCH is used for transmitting the control information. This PDCCH is composed of one or a plurality of L1 / L2 CCHs (L1 / L2 Control Channel). Each L1 / L2CCH is composed of one or a plurality of CCEs (Control Channel Element). That is, CCE is a basic unit for mapping control information to PDCCH. When one L1 / L2CCH is composed of a plurality of CCEs, a plurality of CCEs having consecutive identification numbers (Index) are assigned to the L1 / L2CCH. The base station allocates L1 / L2 CCH to the resource allocation target terminal according to the number of CCEs required for reporting control information to the resource allocation target terminal. Then, the base station maps the physical resource corresponding to the CCE of this L1 / L2CCH and transmits control information.

Also, here, each CCE is associated with the PUCCH configuration resource on a one-to-one basis. Therefore, the terminal that has received the L1 / L2CCH can implicitly specify the configuration resource of the PUCCH corresponding to the CCE that configures the L1 / L2CCH, and uses this specified resource to transmit a response signal. Transmit to the base station. However, when the L1 / L2 CCH occupies a plurality of continuous CCEs, the terminal may use one of a plurality of PUCCH configuration resources corresponding to the plurality of CCEs (for example, a PUCCH configuration corresponding to the CCE having the smallest Index). Resource) is used to transmit a response signal to the base station. Thus, downlink communication resources are efficiently used.

As shown in FIG. 1, a plurality of response signals and reference signals transmitted from a plurality of terminals are a ZAC (Zero Auto-correlation) sequence (Base sequence) having a Zero Auto-correlation characteristic on a time axis (Time domain). And is spread by a Walsh sequence or a DFT (Discrete-Fourier-Transform) sequence and code-multiplexed in a PUCCH (however, a ZAC sequence having a sequence length of 12 is itself a reference signal sequence (Reference sequence) )).

In FIG. 1, (W ₀ , W ₁ , W ₂ , W ₃ ) represents a Walsh code sequence (Walsh Code Sequence), and (F ₀ , F ₁ , F ₂ ) has a sequence length of 3. Represents a DFT sequence. As shown in FIG. 1, in the terminal, an ACK or NACK response signal is first spread in a 1SC-FDMA symbol by a ZAC sequence (sequence length 12) on the frequency axis. Next, the response signal after the first spreading is associated with each of W ₀ to W _{3 and} subjected to IFFT (Inverse Fast Fourier Transform). Also, in the terminal, a ZAC sequence having a sequence length of 12 as a reference signal is IFFT associated with each of F ₀ to F ₂ . In this manner, the response signal and the reference signal spread by the ZAC sequence having a sequence length of 12 on the frequency axis (Frequency domain) are converted into a ZAC sequence having a sequence length of 12 on the time axis by IFFT. This is equalization, in which the response signal after the first spreading and the reference signal are further subjected to the second spreading using the Walsh sequence (sequence length 4) and the DFT sequence (sequence length 3) after the IFFT.

Response signals from different terminals are spread using ZAC sequences corresponding to different cyclic shift amounts (Cyclic shift Index) or orthogonal code sequences corresponding to different sequence numbers (Orthogonal cover Index: OC index). . The orthogonal code sequence is a set of a Walsh sequence and a DFT sequence. The orthogonal code sequence may also be referred to as a block-wise spreading code sequence. Therefore, the base station can separate these response signals that have been code-multiplexed by using conventional despreading and correlation processing (see Non-Patent Document 4).

However, since each terminal blindly determines downlink allocation control information addressed to itself in each subframe (transmission unit time), the terminal side does not necessarily successfully receive downlink allocation control information. When a terminal fails to receive downlink allocation control information addressed to itself in a certain downlink unit band, the terminal cannot even know whether downlink data destined for itself exists in the downlink unit band. Therefore, when the terminal fails to receive downlink allocation control information in a certain downlink unit band, the terminal does not generate a response signal for downlink data in the downlink unit band. This error case is defined as DTX (DTX (Discontinuous transmission) of ACK / NACK s signals) of the response signal in the sense that the response signal is not transmitted on the terminal side.

By the way, the above-described uplink control channel (PUCCH) is used for indicating the generation of uplink data to be transmitted from the terminal side (that is, for requesting resource allocation for uplink data transmission to the base station). ) It is also used for notification of SR (Scheduling Request: Scheduling Request) (which may be expressed as SRI: Scheduling Request). When a base station establishes a connection with a terminal, the base station individually allocates a resource to be used for SR notification (hereinafter referred to as an SR resource) to each terminal. Moreover, OOK (On-Off-Keying) is applied to this SR, and the base station side determines the SR from the terminal based on whether or not the terminal transmits an arbitrary signal using the SR resource. Is detected. In addition, spreading using a ZAC sequence, a Walsh sequence, and a DFT sequence is applied to SR similarly to the response signal described above.

In the LTE system, SR and response signal may occur within the same subframe. In this case, if one terminal code-multiplexes the SR and the response signal in the same subframe and transmits them simultaneously, the PAPR (Peak-to-Average-Power-Ratio) of the composite waveform of the signal transmitted by the terminal greatly deteriorates. . However, in the LTE system, since the amplifier efficiency of the terminal is regarded as important, when the SR and the response signal are generated in the same subframe on the terminal side, the terminal should use the resource (hereinafter, referred to as the resource to be transmitted). Without using "ACK / NACK resource"), a response signal is transmitted using SR resources individually allocated in advance for each terminal. As a result, the PAPR of the composite waveform of the signal transmitted by the terminal can be kept low. At this time, the base station side detects the SR from the terminal side based on whether or not the SR resource is used. Further, on the base station side, based on the phase of the signal transmitted with the SR resource (or the ACK / NACK resource when SR resource is not used) (that is, the BPSK demodulation result), the terminal performs ACK or NACK. It is determined which one has been notified.

Here, the operation related to the notification of the SR and the response signal on the terminal side in the LTE system described above will be described with reference to FIGS. In FIG. 2, ACK / NACK resources and SR resources are allocated to different code resources. In the downlink unit band shown in FIG. 2, the base station uses the L1 / L2CCH (channel constituted by one or a plurality of CCEs) included in the PDCCH to indicate downlink allocation control indicating resources for transmitting downlink data. Send information. Further, as shown in FIG. 2, the base station allocates in advance one arbitrary PUCCH resource included in the PUCCH of the uplink unit band as a PUCCH resource (SR resource) for SR. Also, the terminal uses one PUCCH resource associated with the CCE (PDCCH) occupied by the downlink allocation control information in the downlink unit band as a PUCCH resource (ACK / NACK resource) for response signals.

First, as shown in FIG. 3A, when the terminal notifies the SR and the response signal within a certain subframe (that is, when SR + ACK or SR + NACK is notified), the terminal transmits the downlink data channel (PDSCH) shown in FIG. : A response signal ("A / N") for downlink data (DL data) received by Physical Downlink Shared Channel) is allocated to one SR resource included in the PUCCH of the uplink unit band shown in FIG. 3A. And a terminal determines the phase of the signal transmitted using SR resource according to whether a response signal is ACK or NACK.

Next, as shown in FIG. 3B, when the terminal transmits only a response signal within a certain subframe (that is, when only ACK or NACK is transmitted), the terminal receives the downlink received on the PDSCH shown in FIG. A response signal ("A / N") for data (DL data) is allocated to one ACK / NACK resource included in the PUCCH of the uplink unit band shown in FIG. 3B. And a terminal determines the phase of the signal transmitted using an ACK / NACK resource according to whether a response signal is ACK or NACK.

Next, as illustrated in FIG. 3C, when the terminal notifies only of the SR within a certain subframe, the terminal allocates the SR to one SR resource included in the PUCCH of the uplink unit band illustrated in FIG. 3C. Then, the terminal sets a NACK phase point for the SR resource.

However, as described above, since the terminal side does not always succeed in receiving downlink allocation control information, there is a difference in recognition regarding the success or failure of downlink signal reception at the terminal side between the base station side and the terminal side. there is a possibility. Specifically, when the base station transmits downlink allocation control information (and downlink data) to the terminal, when the terminal transmits an uplink response signal using the SR resource, the base station not only performs SR detection. , It is determined whether the phase of the signal allocated to the SR resource indicates ACK or NACK information. However, if reception of downlink allocation control information has failed on the terminal side (that is, when DTX occurs), the terminal does not include the response signal information in the uplink response signal, and only uses the SR resource to transmit the SR. Notify. Therefore, in the LTE system, as shown in FIG. 3, when the terminal notifies only the SR to the base station (FIG. 3C), the SR and NACK information are transmitted in the same subframe so that these recognition differences do not become a big problem. The same signal point (that is, the phase point of NACK) is used in the case of notifying the base station in FIG. 3A (FIG. 3A). In this way, even if the terminal fails to receive the downlink allocation control information and notifies only the SR (that is, during SR + DTX communication), the base station side uses the same sub-signal for SR and NACK information. Since it is determined that the frame is notified (that is, SR + NACK), the downlink data retransmission control can be executed without any major problem.

Also, standardization of 3GPP LTE-advanced, which realizes higher communication speed than 3GPP LTE, has started. The 3GPP LTE-advanced system (hereinafter sometimes referred to as “LTE-A system”) follows the 3GPP LTE system (hereinafter sometimes referred to as “LTE system”). In 3GPP LTE-advanced, it is expected that base stations and terminals capable of communicating at a wideband frequency of 40 MHz or more will be introduced in order to realize a downlink transmission speed of 1 Gbps or more at the maximum.

In the LTE-A system, in order to simultaneously realize communication at an ultra-high speed transmission speed several times the transmission speed in the LTE system and backward compatibility with the LTE system (Backward Compatibility), the LTE- The band for the A system is divided into “unit bands” of 20 MHz or less, which is the support bandwidth of the LTE system. That is, the “unit band” is a band having a maximum width of 20 MHz, and is defined as a basic unit of the communication band. Furthermore, the “unit band” (hereinafter referred to as “downlink unit band”) in the downlink is a band delimited by downlink frequency band information in the BCH broadcast from the base station, or the downlink control channel (PDCCH) is a frequency. It may be defined as a band defined by a dispersion width when distributed in a region. Also, the “unit band” (hereinafter referred to as “uplink unit band”) in the uplink is a band delimited by uplink frequency band information in the BCH broadcast from the base station, or a PUSCH (Physical-Uplink) near the center. In some cases, it is defined as a basic unit of a communication band of 20 MHz or less that includes a (Shared CHannel) region and includes PUCCH for LTE at both ends. The “unit band” may be expressed in English as “Component Carrier (s)” in 3GPP LTE-Advanced. A “unit band” may be defined by a physical cell number and a carrier frequency number, and may be called a “cell”.

The LTE-A system supports communication using a band obtained by bundling several unit bands, so-called Carrier Aggregation. In general, an uplink throughput request and a downlink throughput request are different from each other. Therefore, in the LTE-A system, an arbitrary LTE-A system compatible terminal (hereinafter referred to as “LTE-A terminal”) is set. Carrier-aggregation, in which the number of unit bands to be used differs between upstream and downstream, so-called Asymmetric Carrier-aggregation is also being studied. Furthermore, the case where the number of unit bands is asymmetric between upstream and downstream and the frequency bandwidth of each unit band is different is also supported.

FIG. 4 is a diagram for explaining an asymmetric carrier aggregation applied to individual terminals and a control sequence thereof. FIG. 4 shows an example in which the uplink and downlink bandwidths and the number of unit bands of the base station are symmetric.

In FIG. 4B, the terminal 1 is configured to perform carrier-aggregation using two downlink unit bands and one uplink unit band on the left side. In spite of the setting that uses the same two downlink unit bands as those of the terminal 1, the setting that uses the right uplink unit band is performed in the uplink communication.

When attention is paid to the terminal 1, signals are transmitted and received between the LTE-A base station and the LTE-A terminal constituting the LTE-A system according to the sequence diagram shown in FIG. 4A. As shown in FIG. 4A, (1) Terminal 1 synchronizes with the left downlink unit band at the start of communication with the base station, and transmits information on the uplink unit band paired with the left downlink unit band to SIB2 Read from a notification signal called (System Information Block Type 2). (2) Using this uplink unit band, the terminal 1 starts communication with the base station, for example, by transmitting a connection request to the base station. (3) When determining that it is necessary to assign a plurality of downlink unit bands to the terminal, the base station instructs the terminal to add a downlink unit band. However, in this case, the number of uplink unit bands does not increase, and asymmetric carrier aggregation is started in terminal 1, which is an individual terminal.

In addition, in the LTE-A system to which the above-described Carrier Aggregation is applied, a terminal may receive a plurality of downlink data in a plurality of downlink unit bands at a time. In the LTE-A system, as one method of transmitting a plurality of response signals for the plurality of downlink data, the response signals for the plurality of downlink data are collectively encoded (Joint coding), and the encoded data is converted into DFT. A method of transmitting to a base station using an S-OFDMA (Discrete-Fourier-Transform-spread-Orthogonal-Frequency-Division-Multiple-Access) format has been studied (see Non-Patent Document 5). Each of the error detection results for each downlink unit band is included as individual data in the encoded data in which response signals for a plurality of downlink data are collectively encoded (Joint coding). The response signals for the plurality of downlink data are collectively encoded (Joint coding), and the encoded data including each error detection result for each downlink unit band is hereinafter referred to as a “bundled ACK / NACK signal” or This is called a “bundle response signal”.

A method for transmitting a bundled ACK / NACK signal using the DFT-S-OFDMA format will be described with reference to FIG.

As a reference signal used for demodulating the bundle ACK / NACK signal, a “ZAC sequence (Base sequence) having a sequence length of 12” similar to the reference signal in LTE is used. Specifically, a ZAC sequence having a sequence length of 12 is arranged in the third, fourth, and fifth SC-FDMA symbols, and is spread in correspondence with each DFT sequence (sequence length 3: F ₀ , F ₁ , F ₂ ). The Further, the spread signal is converted into a signal on the time axis by IFFT. In these processes, the ZAC sequence is converted into a signal on the time axis by IFFT and then spread by a DFT sequence having a sequence length of 3 and equalization.

Reference signals from different terminals are spread using sequences corresponding to different cyclic shift amounts (Cyclic shift Index) or different DFT sequences, as in the case of reference signals for ACK / NACK in LTE. By using conventional despreading processing and correlation processing, it is possible to separate a plurality of these code-multiplexed reference signals.

In the DFT-S-OFDMA format shown in FIG. 5, as described above, a “ZAC sequence having a sequence length of 12” is used as a reference signal. In this case, as a bundled ACK / NACK signal, a signal composed of 12 symbols is first DFTed and first spread in one SC-FDMA symbol. As described above, in the LTE system, a 1-symbol response signal subjected to BPSK modulation is first spread in a 1SC-FDMA symbol by a ZAC sequence (sequence length 12) on the frequency axis. On the other hand, in the LTE-A system to which Carriergregaggregation is applied, when a bundle ACK / NACK signal is notified using DFT-S-OFDMA, a “ZAC sequence having a sequence length of 12” is used as a reference signal. In this case, a bundle ACK / NACK signal composed of 12 symbols is DFT and first spread in one SC-FDMA symbol. As described above, the bundle ACK / NACK signal composed of 12 symbols includes each error detection result for each downlink unit band as individual data.

Next, the bundle ACK / NACK signal after DFT is arranged in the _first , _second , sixth, and seventh SC-FDMA symbols, and is made to correspond to each Walsh sequence (sequence length 4: W ₀ , W ₁ , W ₂ , W ₃ ). Diffuse. Further, the spread signal is converted into a signal on the time axis by IFFT. These processes are equalization, in which each element component of a Walsh sequence having a sequence length of 4 is multiplied by a signal after being converted into a signal on the time axis by IFFT.

Here, bundled ACK / NACK signals from different terminals are code-multiplexed by spreading bundled ACK / NACK signals using different Walsh sequences. That is, since bundle ACK / NACK signals are spread by a Walsh sequence having a sequence length of 4, it is possible to code-multiplex bundle ACK / NACK signals from a maximum of four terminals.

Then, a CP (Cyclic Prefix) is added to each signal after IFFT to form a one-slot signal composed of seven SC-FDMA symbols.

Hereinafter, a resource that adopts the OFT-S-OFDM format configuration and transmits a bundled ACK / NACK signal is referred to as a “bundle ACK / NACK resource”. As shown in FIG. 5, a bundle ACK / NACK signal is a data portion (in the example of FIG. 5, the first ACK / NACK signal is a first portion in the case where downlink data is transmitted using the DFT-S-OFDMA format. , 2, 6, 7 SC-FDMA symbols). A reference signal for demodulating the bundle ACK / NACK signal is time-multiplexed with the bundle ACK / NACK signal.

In the LTE-A system, as shown in FIG. 6, it is assumed that the base station individually notifies the terminal of SR resources (the same format as LTE) and bundled ACK / NACK resources. Then, the terminal identifies the SR resource and the bundle ACK / NACK resource.

FIG. 7 shows an SR resource (see FIG. 7A) in an LTE-A system to which Carrier-aggregation is applied, and a bundle ACK / NACK resource when a bundle ACK / NACK signal is reported using the DFT-S-OFDM format (FIG. 7). FIG. 7B) is a diagram showing an example. The SR resource in the LTE-A system has the same format configuration as the SR resource or the ACK / NACK resource in the LTE system. On the other hand, the bundle ACK / NACK resource in the LTE-A system has a format configuration different from that of the SR resource in the LTE-A system.

And when a terminal notifies only SR, it notifies SR using the SR resource notified from the base station beforehand (refer FIG. 7A), and when a terminal notifies only bundle ACK / NACK signal, it is a terminal. Notifies bundle ACK / NACK using bundle ACK / NACK resources (see FIG. 7B).

However, in the LTE-A system to which Carrier-aggregation using a plurality of downlink unit bands is applied, when the format configuration of the SR resource and the bundle ACK / NACK resource is different as shown in FIG. 7, the bundle ACK / NACK signal A method for notifying the SR and the bundled ACK / NACK signal in the same subframe while maintaining the quality of the above has not been sufficiently studied so far.

An object of the present invention is when a SR requesting resource allocation for uplink data transmission and a bundle response signal occur in the same subframe in a communication system to which Carrier Aggregation using a plurality of downlink unit bands is applied. And providing a terminal apparatus, a base station apparatus and a signal transmission control method capable of maintaining the quality of the bundle response signal.

The terminal device according to the present invention includes a receiving unit that receives downlink data allocated to a plurality of downlink unit bands, a generating unit that generates a bundle response signal including each error detection result for each downlink unit band, and the bundle. And a transmission unit that multiplexes and transmits a reference signal to the response signal, and the transmission unit notifies the scheduling request using a reference signal resource in which the reference signal is arranged.

In the base station apparatus of the present invention, a bundle response signal including a plurality of error detection results for each of a plurality of downlink unit bands, a receiving unit that receives a reference signal multiplexed on the bundle response signal, and the reference signal are arranged. And detecting means for detecting the presence / absence of a scheduling request by using the reference signal resource.

The signal transmission control method of the present invention receives downlink data assigned to a plurality of downlink unit bands, generates a bundle response signal including each error detection result for each downlink unit band, and refers to the bundle response signal A signal is multiplexed and transmitted, and a scheduling request is notified by a reference signal resource in which the reference signal is arranged.

According to the present invention, in a communication system to which carrier aggregation using a plurality of downlink unit bands is applied, when an SR requesting resource allocation for uplink data transmission and a bundle response signal occur in the same subframe In addition, the quality of the bundle response signal can be maintained.

The figure which shows the spreading | diffusion method of a response signal and a reference signal The figure which shows the operation | movement regarding transmission of SR and a response signal by the terminal side The figure which shows the transmission control process of the terminal according to the generation condition of SR, and the generation condition of a response signal Diagram for explaining asymmetric Carrier Car aggregation and its control sequence applied to individual terminals The figure which shows the spreading | diffusion method of ACK / NACK (symbol) (bundled ACK / NACK signal after error correction encoding) with respect to several downlink unit band The figure with which it uses for description of the signal transmission control method which concerns on this Embodiment The figure which shows the resource for SR and bundle ACK / NACK resource in LTE-A The figure which uses for description of the signal transmission control method (response pattern) which concerns on embodiment The block diagram which shows the structure of the base station which concerns on embodiment of this invention The block diagram which shows the structure of the terminal which concerns on embodiment The figure which uses for description of another signal transmission control method (response pattern) which concerns on embodiment The figure where it uses for description of the 1st example of a setting of the reference signal resource which concerns on embodiment The figure which uses for description of the 2nd setting example of the reference signal resource which concerns on embodiment The figure which shows another spreading | diffusion method of a response signal and a reference signal

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, before describing the specific configuration and operation of the embodiment, in the LTE-A system to which Carrier Aggregation using a plurality of downlink unit bands is applied, SR and bundled ACK / NACK signals are assigned to the same subframe. As a notification method, a method focused on by the present inventors will be described.

As notification methods when SR and bundled ACK / NACK signals are generated in the same subframe (that is, response patterns (arrangement patterns) of these response signals), methods 1 to 3 shown in FIG. 8 are used. Two methods (response patterns 01 to 03) are conceivable.

Method 1 (response pattern 01): Similar to the LTE system, a bundle ACK / NACK signal is placed in the SR resource. However, since the number of symbols constituting the bundle ACK / NACK signal is larger than that of the ACK / NACK signal in the LTE system, only part of the information of the bundle ACK / NACK signal is arranged in the SR resource.

Method 2 (response pattern 02): SR and bundle ACK / NACK signals are arranged in SR resource and bundle ACK / NACK resource, respectively.

Method 3 (response pattern 03): A bundle ACK / NACK signal is always encoded together with an SR, and the obtained encoded data is arranged in a bundle ACK / NACK resource.

By using the above methods 1 to 3, the SR and the bundle ACK / NACK signal can be notified in the same subframe. However, in Method 1, since a part of the bundled ACK / NACK signal is lost, the retransmission efficiency of downlink data decreases. In the LTE system, since the ACK / NACK signal is composed of one symbol, all of the ACK / NACK information can be notified using the SR resource (the transmission of information of one symbol is possible). On the other hand, when the bundle ACK / NACK signal uses a bundle ACK / NACK resource having a DFT-S-OFDM format configuration, each of the error detection results for each downlink unit band is individually included in the bundle ACK / NACK signal. Included as data. For example, when a bundle ACK / NACK resource adopting the DFT-S-OFDM format configuration shown in FIG. 5 is used, the bundle ACK / NACK signal is composed of 12 symbols. Therefore, when a bundle ACK / NACK signal is notified using SR resources, a part of the bundle ACK / NACK signal is lost. Also, in Method 2, the single carrier characteristics of the transmission signal waveform transmitted from the terminal are lost, so the PAPR increases and the power efficiency of the terminal is greatly degraded. In Method 3, the coding rate of the bundled ACK / NACK signal decreases due to the presence of the SR, so that the transmission quality of the bundled ACK / NACK signal deteriorates.

Therefore, in the following, in the LTE-A system to which carrier-aggregation using a plurality of downlink unit bands is applied, a transmission transmitted from a terminal when notifying an SR and a bundled ACK / NACK signal in the same subframe While maintaining the single-carrier characteristics of the signal waveform (while keeping the PAPR low) and without reducing the coding rate of the bundled ACK / NACK signal, all ACK / NACK information (that is, for each of multiple downlink unit bands) A base station, a terminal, and a signal transmission control method capable of transmitting all of the error detection results) to the base station and maintaining the transmission quality of the bundled ACK / NACK signal will be described.

[Base station configuration]
FIG. 9 is a block diagram showing a configuration of base station 100 according to the present embodiment. 9, the base station 100 includes a control unit 101, a control information generation unit 102, an encoding unit 103, a modulation unit 104, an encoding unit 105, a data transmission control unit 106, a modulation unit 107, Mapping unit 108, IFFT (Inverse Fast Fourier Transform) unit 109, CP adding unit 110, radio transmitting unit 111, radio receiving unit 112, CP removing unit 113, PUCCH extracting unit 114, and despreading unit 115 A sequence control unit 116, a correlation processing unit 117, an SR detection unit 118, a bundle A / N despreading unit 119, an IDFT (Inverse Discrete Fourier Transform) unit 120, a bundle A / N determination unit 121, A retransmission control signal generation unit 122.

The control unit 101 transmits, to a resource allocation target terminal (hereinafter also referred to as “destination terminal” or simply “terminal”) 200, downlink resources for transmitting control information (that is, downlink control information allocation resources), and downlink A downlink resource (that is, a downlink data allocation resource) for transmitting line data is allocated (assigned). This resource allocation is performed in the downlink unit band included in the unit band group set in the resource allocation target terminal 200. Further, the downlink control information allocation resource is selected in a resource corresponding to a downlink control channel (PDCCH) in each downlink unit band. Further, the downlink data allocation resource is selected in a resource corresponding to a downlink data channel (PDSCH) in each downlink unit band. When there are a plurality of resource allocation target terminals 200, the control unit 101 allocates different resources to each of the resource allocation target terminals 200.

The downlink control information allocation resource is equivalent to the above-mentioned L1 / L2CCH. That is, the downlink control information allocation resource is composed of one or a plurality of CCEs.

Also, the control unit 101 determines a coding rate used when transmitting control information to the resource allocation target terminal 200. Since the data amount of control information differs according to the coding rate, downlink control information allocation resources having a number of CCEs to which control information of this data amount can be mapped are allocated by the control unit 101.

And the control part 101 outputs the information regarding a downlink data allocation resource with respect to the control information generation part 102. FIG. In addition, the control unit 101 outputs information on the coding rate to the coding unit 103. Control section 101 also determines the coding rate of transmission data (that is, downlink data) and outputs the coding rate to coding section 105. In addition, the control unit 101 outputs information on the downlink data allocation resource and the downlink control information allocation resource to the mapping unit 108. However, the control unit 101 controls the downlink data and the downlink control information for the downlink data to be mapped to the same downlink unit band.

The control information generation unit 102 generates control information including information on downlink data allocation resources and outputs the control information to the encoding unit 103. This control information is generated for each downlink unit band. Further, when there are a plurality of resource allocation target terminals 200, the control information includes the terminal ID of the destination terminal 200 in order to distinguish the resource allocation target terminals 200 from each other. For example, a CRC bit masked with the terminal ID of the destination terminal 200 is included in the control information. This control information may be referred to as “downlink assignment control information (Control information carrying downlink assignment)”.

The encoding unit 103 encodes the control information according to the encoding rate received from the control unit 101, and outputs the encoded control information to the modulation unit 104.

Modulation section 104 modulates the encoded control information and outputs the obtained modulated signal to mapping section 108.

The encoding unit 105 receives the transmission data (that is, downlink data) for each destination terminal 200 and the coding rate information from the control unit 101 as input, encodes the transmission data, and outputs the transmission data to the data transmission control unit 106. However, when a plurality of downlink unit bands are allocated to destination terminal 200, the transmission data transmitted in each downlink unit band is encoded, and the encoded transmission data is output to data transmission control section 106. .

The data transmission control unit 106 holds the encoded transmission data and outputs it to the modulation unit 107 during the initial transmission. The encoded transmission data is held for each destination terminal 200. Transmission data to one destination terminal 200 is held for each downlink unit band to be transmitted. As a result, not only retransmission control of the entire data transmitted to the destination terminal 200 but also retransmission control for each downlink unit band is possible.

In addition, when data transmission control section 106 receives NACK or DTX for downlink data transmitted in a certain downlink unit band from retransmission control signal generation section 122, data transmission control section 106 outputs retained data corresponding to this downlink unit band to modulation section 107. To do. When data transmission control section 106 receives ACK for downlink data transmitted in a certain downlink unit band from retransmission control signal generation section 122, data transmission control section 106 deletes the retained data corresponding to this downlink unit band.

Modulation section 107 modulates the encoded transmission data received from data transmission control section 106 and outputs the modulated signal to mapping section 108.

The mapping unit 108 maps the modulation signal of the control information received from the modulation unit 104 to the resource indicated by the downlink control information allocation resource received from the control unit 101, and outputs it to the IFFT unit 109.

Also, the mapping unit 108 maps the modulation signal of the transmission data received from the modulation unit 107 to the resource indicated by the downlink data allocation resource received from the control unit 101, and outputs it to the IFFT unit 109.

Control information and transmission data mapped to a plurality of subcarriers in a plurality of downlink unit bands by mapping section 108 are converted from a frequency domain signal to a time domain signal by IFFT section 109, and a CP is added by CP adding section 110. After being converted into an OFDM signal, transmission processing such as D / A (Digital-to-Analog) conversion, amplification, and up-conversion is performed in the wireless transmission unit 111 and transmitted to the terminal 200 via the antenna.

The radio reception unit 112 receives an uplink response signal or a reference signal transmitted from the terminal 200 via an antenna, and performs reception processing such as down-conversion and A / D conversion on the uplink response signal or the reference signal.

The CP removal unit 113 removes the CP added to the uplink response signal or the reference signal after reception processing.

The PUCCH extraction unit 114 extracts a PUCCH region signal corresponding to a bundle ACK / NACK resource that has been previously notified to the terminal 200 from the PUCCH signal included in the received signal. Here, as described above, the bundle ACK / NACK resource is a resource to which a bundle ACK / NACK signal is to be transmitted, and is a resource that adopts a DFT-S-OFDMA format configuration. Specifically, the PUCCH extraction unit 114 performs the data portion of the PUCCH region corresponding to the bundle ACK / NACK resource (that is, the SC-FDMA symbol in which the bundle ACK / NACK signal is arranged) and the reference signal portion (that is, the bundle). (SC-FDMA symbol in which a reference signal for demodulating the ACK / NACK signal is arranged) is extracted. PUCCH extraction section 114 outputs the extracted data portion to bundle A / N despreading section 119 and outputs the reference signal portion to despreading section 115-1.

Also, the PUCCH extraction unit 114 extracts a PUCCH region corresponding to one SR resource that has been notified to the terminal 200 in advance from the PUCCH signal included in the received signal. Specifically, the PUCCH extraction unit 114 includes a data part (SC-FDMA symbol in which an uplink control signal is allocated) and a reference signal part (a reference signal for demodulating the uplink control signal) corresponding to the SR resource. SC-FDMA symbols) are extracted. Then, PUCCH extraction section 114 outputs both the extracted data portion and reference signal portion to despreading section 115-2.

Sequence control section 116 may use Base sequence (that is, ZAC having a sequence length of 12) that may be used for spreading of the SR, the reference signal for SR notified from terminal 200, and the reference signal for bundled ACK / NACK signal. Series). Also, sequence control section 116 specifies correlation windows corresponding to resources (hereinafter referred to as “reference signal resources”) in which reference signals can be arranged in PUCCH resources that terminal 200 may use. Then, sequence control section 116 outputs information indicating the correlation window corresponding to the reference signal resource in which the reference signal can be arranged in the bundle ACK / NACK resource and Base sequence to correlation processing section 117-1. As will be described later, terminal 200 reserves at least two reference signal resources (hereinafter referred to as “first and second reference signal resources”) as reference signal resources in which reference signals for bundled ACK / NACK signals can be arranged. Has been. Sequence control section 116 outputs information indicating the correlation window (first and second correlation windows) corresponding to each reference signal resource and Base sequence to correlation processing section 117-1. In addition, sequence control section 116 outputs information indicating the correlation window (third correlation window) corresponding to the SR resource in which the SR and the reference signal for SR are arranged and the Base sequence to correlation processing section 117-2.

The despreading unit 115-1 and the correlation processing unit 117-1 perform processing of the reference signal extracted from the PUCCH region corresponding to the bundle ACK / NACK resource.

Specifically, despreading section 115-1 despreads the reference signal portion with the DFT sequence that terminal 200 should use for secondary spreading in the reference signal of the bundle ACK / NACK resource, and correlates the signal after despreading Output to the unit 117-1.

The correlation processing unit 117-1 uses the information indicating the first and second correlation windows and the base sequence corresponding to the first and second reference signal resources, the signal input from the despreading unit 115-1, and the terminal At 200, correlation values (first and second correlation values) with the base sequence that may be used for the first spreading are obtained. Correlation processing section 117-1 then outputs the first and second correlation values to SR detection section 118.

The despreading unit 115-2 and the correlation processing unit 117-2 perform processing of the reference signal and SR extracted from the PUCCH region corresponding to the SR resource.

Specifically, despreading section 115-2 despreads the data portion and the reference signal portion with the Walsh sequence and DFT sequence that terminal 200 should use for secondary spreading in the data portion and reference signal portion of SR resource, and performs despreading. The spread signal is output to correlation processing section 117-2.

Correlation processing section 117-2 can be used for primary spreading in terminal 200 and the signal input from despreading section 115-2 using information indicating the third correlation window corresponding to the SR resource and Base sequence. A correlation value (third correlation value) with a characteristic Base sequence is obtained. Correlation processing section 117-2 then outputs the third correlation value to SR detection section 118.

SR detecting section 118 detects a reference signal resource in which a reference signal transmitted from terminal 200 is arranged based on the first to third correlation values input from correlation processing sections 117-1 and 117-2, The generation status (notification status) of the SR and bundle ACK / NACK signal is determined according to the detected reference signal resource. Details of the method of determining the occurrence status (notification status) in the SR detection unit 118 will be described later.

When the SR detection unit 118 determines that only the bundle ACK / NACK signal is generated in the same subframe, or only the SR and the bundle ACK / NACK signal are generated in the same subframe, the bundle ACK / NACK resource is determined. Is output to the bundle A / N determination unit 121.

Also, when it is determined that only SR occurs in the same subframe, the SR detection unit 118 notifies the bundle A / N determination unit 121 that the use of the bundle ACK / NACK resource has not been detected. If the SR detection unit 118 determines that only SR occurs in the same subframe, the SR detection unit 118 outputs “DTX” information regarding all downlink unit bands to the retransmission control signal generation unit 122.

Furthermore, when the SR detection unit 118 determines that only the SR and the bundled ACK / NACK signal are generated in the same subframe, and determines that only the SR is generated in the same subframe, the SR detection unit 118 transmits information on the SR. Output to a resource allocation control unit (not shown).

When the uplink resource allocation control unit (not shown) receives the SR, the base station 100 transmits uplink allocation control information (Uplink Grant and the uplink data allocation resource) so that the terminal 200 can transmit uplink data. To the terminal 200. In this way, base station 100 determines whether it is necessary to allocate resources for uplink data to terminal 200 based on the uplink control channel. Details of operations in the uplink resource allocation control unit and details of resource allocation operations for uplink data for terminal 200 in base station 100 are omitted.

The bundle A / N despreading section 119 despreads the bundle ACK / NACK signal corresponding to the data portion of the bundle ACK / NACK resource input from the PUCCH extraction section 114 using a Walsh sequence, and outputs the signal to the IDFT section 120 To do.

The IDFT unit 120 converts the bundle ACK / NACK signal on the frequency domain input from the bundle A / N despreading unit 119 into a signal on the time domain by IDFT processing, and converts the bundle ACK / NACK signal on the time domain to The data is output to the bundle A / N determination unit 121.

The bundle A / N determination unit 121 uses the bundle ACK / NACK signal corresponding to the data portion of the bundle ACK / NACK resource input from the IDFT unit 120 as a reference signal for the bundle ACK / NACK signal input from the SR detection unit 118. Demodulate using information. Further, the bundle A / N determination unit 121 decodes the demodulated bundle ACK / NACK signal and outputs the decoded result to the retransmission control signal generation unit 122 as bundle A / N information.

Based on the bundle A / N information input from the bundle A / N determination unit 121 or the DTX information input from the SR detection unit 118, the retransmission control signal generation unit 122 transmits data transmitted in the downlink unit band (downlink). Whether or not (line data) should be retransmitted, and a retransmission control signal is generated based on the determination result. Specifically, when receiving a NACK or DTX for downlink data transmitted in a certain downlink unit band, the retransmission control signal generation unit 122 retransmits a retransmission command indicating a retransmission instruction for the downlink data transmitted in the downlink unit band. A control signal is generated, and the retransmission control signal is output to the data transmission control unit 106. In addition, when receiving a response signal indicating ACK for downlink data transmitted in a certain downlink unit band, retransmission control signal generation section 122 is a retransmission indicating that the downlink data transmitted in the downlink unit band is not retransmitted. A control signal is generated, and the retransmission control signal is output to the data transmission control unit 106.

[Terminal configuration]
FIG. 10 is a block diagram showing a configuration of terminal 200 according to the present embodiment. In FIG. 10, terminal 200 includes radio reception section 201, CP removal section 202, FFT (Fast Fourier Transform) section 203, extraction section 204, demodulation section 205, decoding section 206, determination section 207, Control unit 208, demodulation unit 209, decoding unit 210, CRC unit 211, response signal generation unit 212, encoding / modulation unit 213, primary spreading units 214-1, 214-2, secondary Spreading units 215-1 and 215-2, DFT unit 216, spreading unit 217, IFFT units 218-1, 182-2, and 218-3, CP adding units 219-1, 219-2, and 219-3 A time multiplexing unit 220, a selection unit 221, and a wireless transmission unit 222.

The radio reception unit 201 receives an OFDM signal transmitted from the base station 100 via an antenna, and performs reception processing such as down-conversion and A / D conversion on the received OFDM signal. The received OFDM signal includes a PDSCH signal (downlink data) assigned to a resource in PDSCH or a PDCCH signal (downlink assignment control information) assigned to a resource in PDCCH.

CP removing section 202 removes the CP added to the OFDM signal after reception processing.

The FFT unit 203 performs FFT on the received OFDM signal and converts it into a frequency domain signal, and outputs the obtained received signal to the extracting unit 204.

The extraction unit 204 extracts a downlink control channel signal (PDCCH signal) from the received signal received from the FFT unit 203 according to the input coding rate information. That is, since the number of CCEs constituting the downlink control information allocation resource changes according to the coding rate, the extraction unit 204 extracts the downlink control channel signal using the number of CCEs corresponding to the coding rate as an extraction unit. . Further, the downlink control channel signal is extracted for each downlink unit band. The extracted downlink control channel signal is output to demodulation section 205.

Further, the extraction unit 204 extracts downlink data (downlink data channel signal (PDSCH signal)) from the received signal based on the information on the downlink data allocation resource addressed to the own device received from the determination unit 207 described later, and the demodulation unit To 209.

The demodulation unit 205 demodulates the downlink control channel signal received from the extraction unit 204 and outputs the obtained demodulation result to the decoding unit 206.

The decoding unit 206 decodes the demodulation result received from the demodulation unit 205 according to the input coding rate information, and outputs the obtained decoding result to the determination unit 207.

The determination unit 207 blindly determines whether or not the control information included in the decoding result received from the decoding unit 206 is control information addressed to the own device. This determination is performed in units of decoding results corresponding to the above extraction units. For example, the determination unit 207 demasks the CRC bits with the terminal ID of the own device, and determines that the control information in which CRC = OK (no error) is the control information addressed to the own device. Then, the determination unit 207 outputs, to the extraction unit 204, information related to downlink data allocation resources for the own device, which is included in the control information addressed to the own device.

In addition, when the determination unit 207 detects control information addressed to itself (that is, downlink allocation control information), the determination unit 207 notifies the control unit 208 that a bundled ACK / NACK signal is generated (exists).

The control unit 208 outputs the Base sequence and cyclic shift amount corresponding to the SR resource notified from the base station 100 in advance to the primary spreading unit 214-1 and outputs the Walsh sequence and DFT sequence corresponding to the SR resource to 2 Output to the next diffusion unit 215-1. Control unit 208 also outputs the frequency resource information of the SR resource to IFFT unit 218-1.

Further, the control unit 208 arranges the reference signal in the bundled ACK / NACK resource based on the generation status of the SR that requests the resource allocation for uplink data transmission and the bundled ACK / NACK signal in the same subframe. Control resources. Then, the control unit 208 outputs the Base sequence and the cyclic shift amount corresponding to the reference signal portion (reference signal resource) of the bundled ACK / NACK resource previously notified from the base station 100 to the primary spreading unit 214-2. The DFT sequence is output to the secondary spreading section 215-2. Further, control unit 208 outputs the frequency resource information of the bundled ACK / NACK resource to IFFT unit 218-2.

Also, the control unit 208 outputs the Walsh sequence used for spreading the data portion of the bundled ACK / NACK resource to the spreading unit 217, and outputs the frequency resource information of the bundled ACK / NACK resource to the IFFT unit 218-3.

Further, when there is no bundled ACK / NACK signal to be notified in the subframe that has received the SR (that is, when no downlink allocation control information is detected), the control unit 208 sends a NACK to the response signal generation unit 212. A signal corresponding to the phase point is output, and the selection unit 221 is instructed to select the SR resource (that is, the signal input from 219-1) and to output to the wireless transmission unit 222. Further, the control unit 208 notifies the selection unit 221 of the bundled ACK / NACK resource (that is, when downlink allocation control information is detected) when notifying the bundled ACK / NACK signal in the subframe that has received the SR. A signal input from the time multiplexing unit 220 is selected, and the wireless transmission unit 222 is instructed to output.

In this way, the control unit 208 controls the reference signal resource for arranging the reference signal in the bundled ACK / NACK resource based on the generation status of the SR and the bundled ACK / NACK signal in the same subframe. Details of the control method of the reference signal resource in the control unit 208 will be described later.

Demodulation section 209 demodulates the downlink data received from extraction section 204, and outputs the demodulated downlink data to decoding section 210.

Decoding section 210 decodes the downlink data received from demodulation section 209 and outputs the decoded downlink data to CRC section 211.

The CRC unit 211 generates the decoded downlink data received from the decoding unit 210, detects an error for each downlink unit band using the CRC, and if CRC = OK (no error), the ACK and CRC = NG In the case of (there is an error), NACK is output to the response signal generation unit 212. Also, CRC section 211 outputs the decoded downlink data as received data when CRC = OK (no error).

Response signal generation section 212 is input from CRC section 211 based on the reception status of downlink data in each downlink unit band (downlink data error detection result) and the phase point indicated by control section 208. The device generates a bundle ACK / NACK signal (bundle response signal) to be transmitted to the base station 100. Here, each bundled ACK / NACK signal includes each error detection result for each downlink unit band as individual data. The response signal generation unit 212 outputs the generated bundle ACK / NACK signal to the encoding / modulation unit 213.

The encoding / modulation unit 213 encodes and modulates the input bundle ACK / NACK signal, generates a modulated signal of 12 symbols, and outputs the modulated signal to the DFT unit 216.

The DFT unit 216 obtains 12 signal components on the frequency axis by collecting 12 input time-series bundle ACK / NACK signals and performing DFT processing. Then, the DFT unit 216 outputs the 12 signal components to the spreading unit 217.

Spreading section 217 spreads the 12 signal components input from DFT section 216 using the Walsh sequence specified by control section 208, and outputs the result to IFFT section 218-3.

Also, the primary spreading sections 214-1 and 214-2 corresponding to the SR resource and the first and second reference signal resources of the bundled ACK / NACK resource receive the uplink control signal (ie, NACK) according to the instruction of the control section 208. Or the reference signal is spread by the Base sequence corresponding to the resource, and the spread signal is output to the secondary spreading sections 215-1 and 215-2.

Secondary spreading sections 215-1 and 215-2, based on an instruction from control section 208, spread the input primary spread signal using a Walsh sequence or a DFT sequence, and send it to IFFT sections 218-1 and 181-2. Output.

The IFFT units 218-1, 218-2, and 218-3 perform IFFT processing in accordance with the instruction from the control unit 208 in association with the input signal to the frequency position to be arranged. As a result, signals input to IFFT sections 218-1, 182-2, and 218-3 (that is, SR signal, SR resource reference signal, bundle ACK / NACK resource reference signal, bundle ACK / NACK signal) are Converted to time domain signal.

CP adding sections 219-1, 219-2, and 219-3 add the same signal as the tail part of the signal after IFFT to the head of the signal as a CP.

The time multiplexing unit 220 receives the bundle ACK / NACK signal input from the CP addition unit 219-3 (that is, the signal transmitted using the data portion of the bundle ACK / NACK resource) and the CP addition unit 219-2. The bundled ACK / NACK resource reference signal is time-multiplexed with the bundled ACK / NACK resource, and the obtained signal is output to the selection unit 221.

The selection unit 221 selects either a bundled ACK / NACK resource input from the time multiplexing unit 220 or an SR resource input from the CP addition unit 219-1 according to an instruction from the control unit 208, and assigns it to the selected resource The received signal is output to the wireless transmission unit 222.

The radio transmission unit 222 performs transmission processing such as D / A conversion, amplification, and up-conversion on the signal received from the selection unit 221, and transmits the signal from the antenna to the base station 100.

As described above, the determination unit 207, the control unit 208, the time multiplexing unit 220, the selection unit 221, and the wireless transmission unit 222 function as a transmission unit that notifies the SR.

[Operations of base station 100 and terminal 200]
Operations of base station 100 and terminal 200 configured as described above will be described. In the following description, it is assumed that both the SR resource and the bundled ACK / NACK resource are configured from the base station 100 to the terminal 200 in the LTE-A system. Terminal 200 selects either SR resource or bundled ACK / NACK resource according to the SR occurrence status and the reception status of downlink allocation control information (that is, the occurrence status of the uplink response signal to be transmitted), Send a signal to the base station.

Here, as shown in FIG. 7 above, SR resources are set in PUCCH1 (PUCCH region 1) for terminal 200, and bundled ACK / NACK resources are set in PUCCH2 (PUCCH region 2). Suppose that

[Response by terminal 200]
When the determination unit 207 detects control information addressed to itself (that is, downlink allocation control information), the control unit 208 indicates that a bundle ACK / NACK signal is generated (exists) (occurrence state of bundle ACK / NACK signal). Notify Also, the CRC unit 211 notifies the response signal generation unit 212 of the reception success / failure status in each downlink unit band, and the response signal generation unit 212 generates a bundle ACK / NACK signal based on information input from the CRC unit 211. . Here, each bundled ACK / NACK signal includes each error detection result for each downlink unit band as individual data.

The control unit 208 performs transmission control of the uplink response signal based on the generation status of the uplink response signal (SR and bundle ACK / NACK signal requesting resource allocation for uplink data transmission) in the same subframe. FIGS. 11A to 11C are diagrams for explaining a signal transmission control method of an uplink response signal by terminal 200. FIG. The control unit 208 arranges the SR, the bundle ACK / NACK signal, and the reference signal in any one of response patterns in FIGS. 11A to 11C to be described later based on the generation status of the SR and the bundle ACK / NACK signal in the same subframe. To do.

Specifically, control unit 208 selects response pattern 1 in FIG. 11A when only SR occurs in the same subframe (occurrence situation 1), and only bundle ACK / NACK signals are generated in the same subframe. In the case (occurrence situation 2), the response pattern 2 in FIG. 11B is selected, and when the SR and the bundle ACK / NACK signal are generated in the same subframe (occurrence situation 3), the response pattern 3 in FIG. 11C is selected. .

<Occurrence situation 1: When terminal 200 notifies only SR (see FIG. 11A)>
When terminal 200 notifies only SR in the same subframe, terminal 200 arranges SR in the SR resource set in PUCCH region 1 according to response pattern 1 in FIG. 11A.

In this case, in terminal 200, control unit 208 provides a sequence (Base sequence) corresponding to the cyclic shift amount of the SR resource to primary spreading unit 214-1, secondary spreading unit 215-1 and IFFT unit 218-1. ), Orthogonal sequence (Orthogonal sequence: that is, a set of Walsh sequence and DFT sequence), and frequency information. Further, the control unit 208 instructs the selection unit 221 to output the signal assigned to the SR resource input from the CP adding unit 219-1 to the wireless transmission unit 222.

<Occurrence situation 2: When terminal 200 notifies only bundle ACK / NACK (see FIG. 11B)>
When terminal 200 notifies only bundled ACK / NACK in the same subframe, terminal 200 performs first control of bundled ACK / NACK resources set in PUCCH region 2 according to response pattern 2 in FIG. 11B. A reference signal for demodulating the bundle ACK / NACK signal is arranged in the signal resource.

In this case, in terminal 200, control section 208 gives a sequence (Base sequence) corresponding to the first cyclic shift amount and a first orthogonality to primary spreading section 214-2 and secondary spreading section 215-2. A sequence (that is, a DFT sequence) is output. Further, the control unit 208 instructs the selection unit 221 to output the signal assigned to the bundle ACK / NACK resource input from the time multiplexing unit 220 to the radio transmission unit 222.

In this way, the reference signal for the bundle ACK / NACK signal is arranged in the first reference signal resource configured by the sequence corresponding to the first cyclic shift amount and the first orthogonal sequence (that is, the DFT sequence). .

<Occurrence situation 3: When terminal 200 notifies bundle ACK / NACK and SR in the same subframe (see FIG. 11C)>
When terminal 200 notifies bundled ACK / NACK and SR in the same subframe, terminal 200 determines the number of bundled ACK / NACK resources set in PUCCH region 2 according to response pattern 3 of FIG. 11C. A reference signal for demodulating a bundle ACK / NACK signal is arranged in 2 reference signal resources.

In this case, in terminal 200, control section 208 provides a sequence corresponding to the second cyclic shift amount (Base sequence) and second orthogonality to primary spreading section 214-2 and secondary spreading section 215-2. A sequence (that is, a DFT sequence) is output. Further, the control unit 208 instructs the selection unit 221 to output the signal assigned to the bundle ACK / NACK resource input from the time multiplexing unit 220 to the radio transmission unit 222.

In this way, the reference signal for the bundled ACK / NACK signal is arranged in the second reference signal resource configured by the sequence corresponding to the second cyclic shift amount and the second orthogonal sequence (that is, the DFT sequence). .

Thus, in the occurrence situation 2 and the occurrence situation 3, the same bundle ACK / NACK resource is used. However, in the occurrence situation 2 and the occurrence situation 3, the reference signals for the bundle ACK / NACK signals are arranged in different code resources. That is, in the occurrence situation 2, the reference signal is arranged in the first reference signal resource, and in the occurrence situation 3, the reference signal is arranged in the second reference signal resource.

At this time, the first and second reference signal resources are each defined by a pair of a cyclic shift amount and an orthogonal code sequence, and the first and second reference signal resources are the cyclic shift amount and the orthogonality constituting the pair. At least one of the code sequences is made different. Thereby, the base station 100 determines the pair of the sequence and the orthogonal sequence corresponding to the cyclic shift amount constituting the reference signal resource in which the reference signal is arranged in the bundle ACK / NACK resource, so that the terminal 200 bundles the bundle. It can be distinguished whether only the ACK / NACK signal is notified or whether the SR and the bundled ACK / NACK signal are notified in the same subframe.

[Response detection in base station 100]
The SR detection unit 118 detects the response pattern of the uplink response signal notified from the terminal 200 based on the first to third correlation values input from the correlation processing units 117-1 and 117-2, and the response pattern The occurrence status of the uplink response signal associated with is detected.

As described above, terminal 200 configures a reference signal resource depending on whether an SR and a bundle ACK / NACK signal are generated in the same subframe or only a bundle ACK / NACK signal is generated in its own device. At least one of the sequence corresponding to the shift amount and the DFT sequence is changed. At this time, when the base station 100 and the terminal 200 notify only the bundle ACK / NACK signal in advance, the first reference signal resource in which the reference signal is arranged, and the SR and the bundle ACK / NACK signal are the same. Information regarding the second reference signal resource in which the reference signal is arranged when notifying in the subframe is shared.

Based on these pieces of information, sequence control section 116 may use Base sequence (that is, a reference signal for SR, SR transmitted from terminal 200, and a reference signal for bundled ACK / NACK signal that may be used for spreading). , A ZAC sequence having a sequence length of 12), and the generated Base sequence is output to the correlation processing unit 117-1. Also, sequence control section 116 specifies correlation windows corresponding to resources in which reference signals are arranged in PUCCH resources that terminal 200 may use, and shows information indicating the specified correlation windows as correlation processing section 117- 1 and 117-2. Specifically, sequence control section 116 includes first and second reference signals corresponding to first and second reference signal resources in which reference signals are arranged in bundle ACK / NACK resources of PUCCH resources that terminal 200 may use. Each of the two correlation windows is specified, and information indicating the specified first and second correlation windows is output to the correlation processing unit 117-1. Also, sequence control section 116 specifies a correlation window corresponding to the reference signal resource in which the reference signal is arranged in the SR resources of the PUCCH resource that terminal 200 may use, and correlates information indicating the specified correlation window. The data is output to the processing unit 117-2.

The SR detection unit 118 receives the first correlation value corresponding to the first reference signal resource and the second correlation value corresponding to the second reference signal resource from the correlation processing unit 117-1 and performs correlation processing. The third correlation value corresponding to the SR resource is input from unit 117-2.

SR detection section 118 determines that the reference signal is arranged in the first reference signal resource if the magnitude of the first correlation value input from correlation processing section 117-1 is greater than or equal to the threshold value. In addition, if the magnitude of the second correlation value input from correlation processing section 117-1 is equal to or greater than the threshold value, SR detection section 118 determines that the reference signal is allocated to the second reference signal resource. If the magnitude of the first and second correlation values input from the correlation processing unit 117-1 is less than the threshold value, the SR detection unit 118 places the reference signal in the first and second reference signal resources. Judge that there is no.

In addition, if the magnitude of the third correlation value input from the correlation processing unit 117-2 is equal to or greater than the threshold, the SR detection unit 118 determines that the reference signal is allocated to the SR resource. In addition, the SR detection unit 118 determines that the SR resource is not used if the magnitude of the third correlation value input from the correlation processing unit 117-2 is less than the threshold value.

Then, based on the reference signal resource in which the reference signal is arranged, the SR detection unit 118 determines whether only SR is generated in the same subframe (occurrence state 1) or only bundle ACK / NACK signal is generated ( Occurrence situation 2), whether SR and bundled ACK / NACK resource signals have occurred (occurrence situation 3) is determined.

Specifically, when the reference signal is arranged in the first reference signal resource in the bundle ACK / NACK resource, it is determined that only the bundle ACK / NACK signal is generated in the same subframe (occurrence state 2). When the reference signal is arranged in the second reference signal resource in the bundle ACK / NACK resource, it is determined that only the SR and bundle ACK / NACK signal are generated in the same subframe (occurrence state 3). When the reference signal is arranged in the SR resource, it is determined that only SR has occurred (occurrence situation 1).

As described above, the response signal generation unit 212 generates a bundle ACK / NACK signal that individually includes each error detection result for each downlink unit band. And the transmission means comprised from the determination part 207, the control part 208, the time multiplexing part 220, the selection part 221, and the radio | wireless transmission part 222 notifies SR according to the reference signal resource which arrange | positions a reference signal. Specifically, the control unit 208 uses the reference signal as a reference signal based on the occurrence status of the SR that requests resource allocation for the bundle ACK / NACK signal and uplink data transmission in the same subframe (transmission unit time). Place in resources. Specifically, when transmitting the bundled AKC / NACK signal, the control unit 208 places the reference signal in the first reference signal resource, and refers to the case when notifying the SR together with the transmission of the bundled ACK / NAACK signal. The signal is arranged in a second reference signal resource different from the first reference signal resource. That is, when only a bundle ACK / NACK signal is generated in the same subframe, the control unit 208 places a reference signal for the bundle ACK / NACK signal in the first reference signal resource, and SR and bundle ACK in the same subframe. When the / NACK signal is generated, the reference signal for the bundled ACK / NACK signal is arranged in a second reference signal resource different from the first reference signal resource.

As a result, when SR and bundle ACK / NACK signals having different numbers of constituent bits are generated in the same subframe, both SR and bundle ACK / NACK signals are arranged and notified in bundle ACK / NACK resources. The transmission signal waveform of the terminal 200 maintains the single-carrier characteristic, and the PAPR can be kept low. In addition, since the SR and the bundle ACK / NACK signal are individually coded instead of being coded together, all the ACK / NACK information can be obtained without reducing the coding rate of the bundle ACK / NACK signal. It can be transmitted to the base station.

<Setting example of first and second reference signal resources>
As described above, terminal 200 demodulates a bundle ACK / NACK signal depending on whether an SR and a bundle ACK / NACK signal are generated in the same subframe or only a bundle ACK / NACK signal is generated. The reference signals used in the above are arranged in different reference signal resources (first reference signal resource or second reference signal resource).

Specifically, in terminal 200, sequence control section 116 changes at least one of the sequence corresponding to the cyclic shift amount constituting the first and second reference signal resources and the DFT sequence. Hereinafter, a method of setting “sequences corresponding to cyclic shift amounts and orthogonal sequences” constituting the first and second reference signal resources will be described.

<Setting example 1>
FIG. 12 is a diagram for explaining a first setting example of reference signal resources. FIG. 12 shows a case where the data part is composed of 4SC-FDMA symbols and the reference signal part is composed of 3SC-FDMA symbols in a bundled ACK / NACK resource adopting the DFT-S-OFDM format structure, as in FIG. An example is shown. In this case, the orthogonal sequence used for spreading the data portion of the bundled ACK / NACK resource is a Walsh sequence with a sequence length of 4, and the orthogonal sequence used for spreading the reference signal portion of the bundled ACK / NACK resource is of sequence length 3. It becomes a DFT series.

As described above, bundled ACK / NACK signals from a plurality of terminals are spread by a Walsh sequence having a sequence length of 4. Therefore, by using different Walsh sequences at different terminals, bundled ACK / NACK from up to four terminals is used. The signal can be code-multiplexed to the same time frequency resource (Resource Block: RB). However, when code-multiplexing bundled ACK / NACK signals from four terminals, it is necessary to define eight reference signal resources that can be separated from each other as shown in FIG. This is because it is necessary to use different reference signal resources (that is, code resources) when each terminal notifies only the bundle ACK / NACK signal and when it notifies the SR and bundle ACK / NACK signal in the same subframe. Because.

This will be described in more detail with reference to FIG. In FIG. 12, there are 36 codes (that is, combinations of sequences (Cyclic shift index) and orthogonal sequences (OC index) corresponding to the cyclic shift amount) used for the reference signal portion. This is because the base signal having a sequence length of 12 and the orthogonal sequence having a sequence length of 3 are used to spread the reference signal, so that 12 cyclic shift amounts and 3 orthogonal sequences can be defined.

In general, reference signals of bundled ACK / NACK resources to be used by four mobile stations are, for example, as shown in FIG. 12, a cyclic shift amount (Cycliccshift index) or an orthogonal sequence (OC Index), in order to avoid mutual interference. ) Are arranged differently.

However, intersymbol interference between sequences corresponding to adjacent cyclic shift amounts occurs depending on the state of propagation of delayed waves in the propagation path, and interference between orthogonal sequences occurs depending on the state of high-speed movement of the terminal. Here, in the present embodiment, since it is necessary to accurately determine which code resource is used to transmit the reference signal by the same terminal, in the setting example 1, the same terminal transmits a bundle ACK / NACK. Both the cyclic shift amount and the orthogonal sequence corresponding to the first reference signal resource used when notifying only the signal and the second reference signal resource used when notifying the SR and the bundled ACK / NACK signal in the same subframe are provided. Set differently.

By doing so, since the orthogonality between the first reference signal resource and the second reference signal resource is increased, whether or not the terminal has notified the SR in the same subframe as the bundled ACK / NACK signal on the base station side. The determination accuracy when determining is improved.

<Setting example 2>
FIG. 13 is a diagram for explaining a second setting example of reference signal resources. FIG. 13 differs from FIG. 5 in the case of a bundle ACK / NACK resource adopting a DFT-S-OFDM format configuration in which the data portion is composed of 5SC-FDMA symbols and the reference signal portion is composed of 2SC-FDMA symbols. An example is shown. In this case, a Walsh sequence having a sequence length of 4 cannot be used for the data portion. In the example shown in FIG. 13, a DFT sequence having a sequence length of 5 is used for the data portion, and a Walsh sequence having a sequence length of 2 is used for the reference signal portion. FIG. 14 is a diagram illustrating a method of spreading bundle ACK / NACK signals and reference signals using the reference signal resources of FIG. In FIG. 14, (F ′ ₀ , F ′ ₁ , F ′ ₂ , F ′ ₃ , F ′ ₄ ) represents a DFT sequence having a sequence length of 5, and (W ′ ₀ , W ′ ₁ ) is a Walsh sequence having a sequence length of 2. Represents.

In this case, bundled ACK / NACK signals from a plurality of terminals can be multiplexed by five different DFT sequences. Therefore, bundled ACK / NACK signals from a maximum of five terminals are assigned to the same time frequency resource (Resource Block: RB). Can be code-multiplexed. Therefore, in this case, it is necessary to define ten reference signal resources that can be separated from each other as shown in FIG.

Also in setting example 2, the first reference signal resource used when the same terminal notifies only the bundle ACK / NACK signal, and the second reference signal used when notifying the SR and bundle ACK / NACK signal in the same subframe. Both the cyclic shift amount corresponding to the resource and the Walsh sequence (sequence length 2) are set to be different.

By doing so, since the orthogonality between the first reference signal resource and the second reference signal resource is increased, the determination accuracy when determining whether or not the terminal has notified the SR in the same subframe on the base station side is increased. improves.

The embodiments of the present invention have been described above.

In the above embodiment, a case has been described in which a ZAC sequence is used for primary spreading in a PUCCH resource, and a pair of Walsh sequence and DFT sequence is used as an orthogonal code sequence for secondary spreading. However, in the present invention, sequences that can be separated from each other by different cyclic shift amounts other than ZAC sequences may be used for the first spreading. For example, a GCL (Generalized Chirp like) sequence, a CAZAC (Constant Amplitude Zero Auto Correlation) sequence, a ZC (Zadoff-Chu) sequence, a PN sequence such as an M sequence or an orthogonal gold code sequence, or a time randomly generated by a computer A sequence having a sharp autocorrelation characteristic on the axis may be used for the first spreading. For secondary spreading, any sequence may be used as the orthogonal code sequence as long as the sequences are orthogonal to each other or sequences that can be regarded as being substantially orthogonal to each other. In the above description, the response signal resource (for example, PUCCH resource) is defined by the cyclic shift amount of the ZAC sequence and the sequence number of the orthogonal code sequence.

In the above embodiment, the control unit 101 of the base station 100 controls the downlink data and the downlink allocation control information for the downlink data to be mapped to the same downlink unit band, but is not limited thereto. . That is, even if the downlink data and the downlink allocation control information for the downlink data are mapped to different downlink unit bands, if the correspondence between the downlink allocation control information and the downlink data is clear, each implementation The technology described in the form can be applied.

Also, in the present embodiment, a case has been described in which IFFT conversion is performed after primary spreading and secondary spreading as the order of processing on the terminal side. However, the order of these processes is not limited to this. As long as there is IFFT processing after the primary diffusion processing, an equivalent result can be obtained regardless of the location of the secondary diffusion processing.

In the above embodiment, the antenna is described as an antenna. However, the present invention can be similarly applied to an antenna port.

An antenna port refers to a logical antenna composed of one or more physical antennas. That is, the antenna port does not necessarily indicate one physical antenna, but may indicate an array antenna composed of a plurality of antennas.

For example, in 3GPP LTE, it is not specified how many physical antennas an antenna port is composed of, but it is specified as a minimum unit in which a base station can transmit different reference signals (Reference signal).

Also, the antenna port may be defined as a minimum unit for multiplying the weight of a precoding vector (Precoding vector).

Further, although cases have been described with the above embodiment as examples where the present invention is configured by hardware, the present invention can also be realized by software in cooperation with hardware.

Further, each functional block used in the description of the above embodiment is typically realized as an LSI which is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. Although referred to as LSI here, it may be referred to as IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

Also, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

Furthermore, if integrated circuit technology that replaces LSI emerges as a result of advances in semiconductor technology or other derived technology, it is naturally also possible to integrate functional blocks using this technology. Biotechnology can be applied.

The disclosure of the specification, drawings, and abstract contained in Japanese Patent Application No. 2010-072766 filed on March 26, 2010 is incorporated herein by reference.

The present invention can be applied to a mobile communication system or the like.

DESCRIPTION OF SYMBOLS 100 Base station 101,208 Control part 102 Control information generation part 103 Coding part 104 Modulation part 105 Coding part 106 Data transmission control part 107 Modulation part 108 Mapping part 109,218-1,218-2,218-3 IFFT part 110, 219-1, 219-2, 219-3 CP addition unit 111, 222

Radio transmission unit

112, 201

Radio reception unit

113, 202 CP removal unit 114 PUCCH extraction unit 115 Despreading unit 116 Sequence control unit 117 Correlation processing unit 118 SR Detection Unit 119 Bundle A / N Despreading Unit 120 IDFT Unit 121 Bundle A / N Determination Unit 122 Retransmission Control Signal Generation Unit 200 Terminal 203 FFT Unit 204

Extraction Unit

205, 209

Demodulation Unit

206, 210 Decoding Unit 207 Determination Unit 211 CRC unit 212 Response signal generation unit 213 Encoding / modification Part 214-1 and 214-2 first spreading section 215-1,215-2 second spreading section 216 DFT unit 217 spreading unit 220 hours multiplexing unit 221 selecting unit

Claims

Receiving means for receiving downlink data allocated to a plurality of downlink unit bands;
Generating means for generating a bundle response signal including each of the error detection results for each downlink unit band;
Transmitting means for multiplexing and transmitting a reference signal to the bundle response signal;
Comprising
The transmission means notifies a scheduling request by a reference signal resource in which the reference signal is arranged.
Terminal device.
The transmission means arranges the reference signal in a first reference signal resource when transmitting the bundle response signal, and notifies the scheduling request together with the transmission of the bundle response signal. Arranged in a second reference signal resource different from the first reference signal resource,
The terminal device according to claim 1.
The first and second reference signal resources are each defined by a pair of a cyclic shift amount and an orthogonal code sequence,
The first and second reference signal resources are different in at least one of the cyclic shift amount and the orthogonal code sequence constituting the pair.
The terminal device according to claim 1.
The first and second reference signal resources are each defined by a pair of a cyclic shift amount and an orthogonal code sequence,
The first and second reference signal resources are different in both the cyclic shift amount and the orthogonal code sequence constituting the pair.
The terminal device according to claim 1.
A bundle response signal including a plurality of error detection results for each of a plurality of downlink unit bands, and a receiving means for receiving a reference signal multiplexed on the bundle response signal;
Detecting means for detecting the presence or absence of a scheduling request according to a reference signal resource in which the reference signal is arranged;
A base station apparatus comprising:
When the reference signal resource is a first reference signal resource, the detection unit determines that there is no scheduling request, and the reference signal resource is different from the first reference signal resource. In the case of determining that there is the scheduling request,
The base station apparatus according to claim 5.
Receive downlink data assigned to multiple downlink unit bands,
Generating a bundle response signal including each error detection result for each downlink unit band;
A reference signal is multiplexed and transmitted to the bundle response signal,
A scheduling request is notified by a reference signal resource in which the reference signal is arranged.
Signal transmission control method.