JP2014204254A - Terminal device, base station device, radio communication system, and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which: if a terminal device is able to detect a signal by interference cancelling in receiving the signal transmitted by MU-MIMO, it needs control information to be reported to paired another terminal device; but the terminal device tries to detect a signal by blind decoding (BD) in the state in which the C-RNTI of the paired other terminal device is not reported; and the amount of calculation of BD is huge because huge candidates exist.SOLUTION: A terminal device for receiving a data signal in which multi-carrier signals from a base station device to a plurality of terminal devices are multiplexed at the same time and the same frequency comprises: a control information separation unit that separates at least one of specific parameters of other terminal devices of which signals are multiplexed, and a parameter only common to terminal devices of which data signals are multiplexed from a received signal; and a control information detection unit that detects control information transmitted to the other terminal devices on the basis of any one of the parameters.

Description

  The present invention relates to a terminal device, a base station device, a wireless communication system, and a communication method.

  The LTE (Long Term Evolution) system, which is a wireless communication system for 3.9th generation mobile phones, has been standardized, and is now one of the 4th generation wireless communication systems. Standardization of A (also referred to as LTE-Advanced, IMT-A, etc.) systems is being carried out.

  The Rel. 11, an IRC receiver (Interference Rejection Combining Receiver) that realizes interference suppression (IS: Interference Suppression) was considered as an Advanced Receiver. Furthermore, Rel. 12, it has been studied to further suppress inter-cell interference (Inter-Cell Interference) and intra-cell interference (Intra-Cell Interference) on the receiver side. Therefore, as an advanced receiver, an iterative interference receiver (iterative IC receiver) or an interference canceling receiver (non-iterative IC receiver) that does not perform repetition has been studied (see Non-Patent Document 1). For example, the iterative IC receiver includes a turbo equalization receiver and a turbo SIC (Successive Interference Cancel) receiver, and the non-iterative IC receiver includes an SIC receiver.

  A terminal device using an iterative / non-iterative IC receiver as a receiver receives an IUI (Inter-User Interference) when receiving a signal transmitted from the base station device by MU-MIMO (Multi-User Multiple Input Multiple Output) transmission. Suppression has been proposed (see Non-Patent Document 2). In this case, the terminal device needs to detect and cancel a signal transmitted to another terminal device multiplexed with MU-MIMO (a paired terminal device). In order to detect a signal transmitted to a terminal device with which the terminal device is paired, control information to be notified to the paired terminal device is required.

  In downlink (communication from the base station apparatus to the terminal apparatus), resources used by the base station apparatus for data transmission and control information such as MCS (Modulation and Coding Scheme) are transmitted from a PDCCH (Physical Downlink Control CHannel). Included in grant. In order to detect the DL grant, the terminal device blindly searches for SS (Search Space), which is a candidate in which a DL grant determined by a C-RNTI (Cell-Radio Network Temporary Identifier), which is a user-specific ID, is arranged. Perform coding (BD: Blind Decoding). When determining whether or not the result decoded by BD is correct, the terminal device performs a check after performing an exclusive OR operation on a CRC (Cyclic Redundancy Check) bit added to the control information and the C-RNTI.

RP-130404 RWS-120005

  When the terminal device can detect signals by iterative / non-iterative IC receiver, the terminal device is notified of DL grant to other paired terminal devices in order to suppress interference by receiving the signal transmitted by MU-MIMO. Information is required. However, if the terminal device tries to detect by BD in a state where the C-RNTI information of the other paired terminal device is not notified, a very large number of candidates exist, and the calculation amount of BD becomes enormous. There was a problem.

  The present invention has been made in view of the above points, and a terminal device that receives data by MU-MIMO transmission reduces the amount of computation of BD for receiving control information of another paired terminal device. A terminal device, a base station device, and a wireless communication system are provided.

  (1) The present invention has been made in order to solve the above-described problem. One aspect of the present invention is that multicarrier signals from a base station apparatus to a plurality of terminal apparatuses are multiplexed at the same time and at the same frequency. A terminal device for receiving a data signal, wherein the terminal device is at least one of a parameter specific to another terminal device multiplexed with a signal from the received signal, or a parameter common only between terminal devices multiplexed with a data signal And a control information detection unit for detecting control information transmitted to the other terminal device based on any one of the parameters.

  (2) In addition, according to one aspect of the present invention, the terminal device is configured to demodulate a multicarrier signal to the other terminal device based on the detected control information, and to demodulate the demodulated multicarrier signal. And a cancel processing unit for canceling from the signal.

  (3) Moreover, 1 aspect of this invention comprises the CCE calculation part which calculates the search space which detects the said control information transmitted to the said other terminal device based on any one of the said parameters.

  (4) Further, according to one aspect of the present invention, the search space is a search space common to terminal devices in which transmission signals to a plurality of terminal devices are multiplexed.

  (5) Further, according to one aspect of the present invention, a CRC calculation unit that calculates a CRC used for error check when detecting the control information transmitted to the other terminal device based on any one of the parameters. It comprises.

  (6) Moreover, according to one aspect of the present invention, the control includes simultaneously the control information used for receiving a desired data signal and the control information transmitted to the other terminal device based on any one of the parameters. Detect information.

  (7) Further, one aspect of the present invention is a base station apparatus that multiplexes and transmits multicarrier signals to be transmitted to a plurality of terminal apparatuses at the same time and the same frequency, and transmits data signals to the terminal apparatuses. At least one of the parameters unique to the other terminal device used for detecting the control information to be transmitted to the other terminal device to be multiplexed or the common parameter only between the terminal devices multiplexed with the data signal is notified.

  (8) Further, according to one aspect of the present invention, any one of the parameters is a parameter for determining a search space for detecting the control information to be transmitted to the other terminal device.

  (9) Further, according to one aspect of the present invention, any one of the parameters is a parameter for calculating a CRC used for error check when detecting the control information transmitted to the other terminal device.

  ADVANTAGE OF THE INVENTION According to this invention, the terminal device which receives data by MU-MIMO transmission can receive the control information of the other terminal device to be paired, without increasing the calculation amount of BD significantly. Furthermore, the terminal device can improve the error rate characteristic and throughput in the detection of the data signal by iterative / non-iterative IC receiver.

1 is a schematic diagram of a downlink of a cellular system according to the present invention. FIG. It is a schematic block diagram which shows an example of a structure of the conventional base station apparatus. It is a schematic block diagram which shows an example of a structure of the conventional terminal device. It is a schematic block diagram which shows an example of a structure of the control information detection part which concerns on 1st Embodiment. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on 1st Embodiment. It is a schematic block diagram which shows an example of a structure of the terminal device which concerns on 1st Embodiment. It is a schematic block diagram which shows an example of a structure of the control information detection part which concerns on 1st Embodiment. It is an example of the flowchart of the blind decoding which concerns on 1st Embodiment. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on 2nd Embodiment. It is a schematic block diagram which shows an example of a structure of the terminal device which concerns on 2nd Embodiment. It is a schematic block diagram which shows an example of a structure of the control information detection part which concerns on 2nd Embodiment. It is an example of the flowchart of the blind decoding which concerns on 2nd Embodiment. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on 3rd Embodiment. It is an example of the flowchart of the blind decoding which concerns on 3rd Embodiment. It is a schematic block diagram which shows an example of a structure of the terminal device which concerns on 4th Embodiment. It is a schematic block diagram which shows an example of a structure of the control information detection part which concerns on 4th Embodiment. It is an example of the flowchart of the blind decoding which concerns on 4th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In each of the following embodiments, a transmission device that performs data transmission is a base station device (eNB; evolved Node B), and a reception device that receives data is a terminal device (user device, UE, mobile station device). Although the present invention is described on the assumption of an LTE system, the present invention may be applied to other systems.

  FIG. 1 is a schematic diagram of a downlink (downlink) of a cellular system according to the present invention. In the cellular system of FIG. 1, a base station apparatus eNB exists, and terminal apparatuses UE1 and UE2 exist in a cell configured by the base station apparatus. Here, the base station apparatus eNB transmits an OFDM (Orthogonal Frequency Division Multiplexing) signal, which is multicarrier transmission, to MU-MIMO (Multi-User Multiple Input Multiple Output) transmission or a plurality of data signals to the same antenna (antenna port). Transmission signals to the terminal apparatuses UE1 and UE2 are transmitted by non-orthogonal data transmission to be multiplexed. The terminal devices UE1 and UE2 detect a desired signal from signals transmitted by spatial multiplexing or non-orthogonal multiplexing. Hereinafter, although the present invention is applicable to non-orthogonal data transmission, only the case of MU-MIMO transmission will be described.

  FIG. 2 is a schematic block diagram showing an example of the configuration of a conventional base station apparatus for performing downlink data transmission. In the base station apparatus of FIG. 2, the data bit string is input to retransmission control sections 101-1 to 101-M, and the A / N for the previous transmission is input from receiving section 110. When ACK (ACKnowledgement) is input, retransmission control sections 101-1 to 101-M discard the data bit string used to generate the transmission signal notified of ACK, and encode a new data bit string to encoding section 102-1. -102-M. When NACK (Negative ACKnowledgement) is input, retransmission control sections 101-1 to 101-M input data bit strings transmitted at the previous transmission timing to encoding sections 102-1 to 102-M. Here, ACK / NACK (A / N) is notified for each terminal device, and when transmitting a plurality of encoded data bit strings (codewords) to one terminal device, it is notified in units of codewords. However, a plurality of code words may be notified by one A / N by bundling or the like. Hereinafter, the encoding units 102-2 to 102-M to the transmission antennas 108-2 to 108-M perform the same processing as the blocks of the encoding unit 102-1 to the transmission antenna 108-1, respectively. Only the processing from 102-1 to the transmitting antenna 108-1 will be described.

  The encoding unit 102-1 performs encoding of an error correction code on the input data bit string. For example, a turbo code, an LDPC (Low Density Parity Check) code, a convolutional code, or the like is used as the error correction code. The type of error correction code applied by the encoding unit 102-1 may be determined in advance by the transmission / reception apparatus, or may be notified as control information for each transmission / reception opportunity. The encoding unit 102-1 performs puncturing on the encoded bit string based on the encoding rate included in the MCS notified to the terminal apparatus by PDCCH (Physical Downlink Control CHannel). Encoding section 102-1 outputs the punctured encoded bit string to modulation section 103-1.

  Modulation section 103-1 modulates the coded bit string input from coding section 102-1 with the modulation scheme notified to the terminal device using PDCCH, thereby generating a modulation symbol string. Examples of the modulation method include QPSK (Quaternary Phase Shift Keying), 16QAM (16-ary Quadrature Amplitude Modulation), and 64 QAM. Modulation section 103-1 inputs the generated modulation symbol sequence to precoding section 114. Precoding section 114 assigns modulation symbols input from modulation sections 103-1 to 103-M to layers. Here, when a plurality of modulation symbol sequences are spatially multiplexed, they are allocated to different layers, and when not spatially multiplexed, they are allocated to the same layer. The precoding unit 114 multiplies the signal sequence allocated to the layer by the precoding matrix, generates a signal for each antenna port, and inputs the signal to the signal allocation units 104-1 to 104-M. In this specification, it is assumed that the number of code words and the number of layers are the same.

  On the other hand, the receiving antenna 109 receives control information transmitted from a terminal apparatus via a PUCCH (Physical Uplink Control CHannel). Control information transmitted on the PUCCH includes SR (Scheduling Request), A / N, and CSI (Channel State Information) which is information on channel quality. The received signal is subjected to processing such as down-conversion and A / D (Analog / Digital) conversion in the receiving unit 110. When receiving the CSI, the receiving unit 110 extracts the CSI and inputs it to the scheduling unit 111. Note that the CSI may be transmitted by the PUSCH. In this case, the reception unit 110 extracts the CSI included in the PUSCH and inputs the CSI to the scheduling unit 111. When receiving the A / N, the receiving unit 110 extracts the A / N and inputs it to the retransmission control units 101-1 to 101-M.

  The scheduling unit 111 receives CSI of a plurality of terminal devices, selects a terminal device that transmits downlink data at the next transmission timing, and assigns frequency resource allocation, rank, MCS (Modulation and Coding) based on the CSI. Scheme), PMI (Precoding Matrix Indicator), antenna port number, and other communication parameters used for downlink transmission are determined. The determined communication parameter is input to the control information generation unit 112. The control information generating unit 112 converts the control information format into a control information format (DCI format: Downlink Control Information format) for each terminal device that notifies the input communication parameter, and the generated control information format is control information multiplexing units 105-1 to 105-105. -Input to M. A DCI format that can be used for MU-MIMO includes Format2C. A transmission mode (Transmission Mode) set for each terminal device is defined, and a terminal device in which a transmission mode in which Format2C can be used is set enables MU-MIMO. In addition, the control information generation unit 112 also transmits control information based on RRC to the control information multiplexing units 105-1 to 105-M at the notification timing such as C-RNTI (Radio Network Temporary Identifier) notified by RRC (Radio Resource Control) signaling. To enter.

  The signal allocation unit 104-1 arranges the modulation symbol sequence in the frequency band based on the information on the frequency resource allocation notified to the terminal device by PDCCH (Physical Downlink Control CHannel). Here, in the case of SU-MIMO (Single User MIMO) or MU-MIMO, spatially multiplexed signals are allocated to the same resource in different layers. The signal allocation unit 104-1 also receives the reference signal generated by the reference signal generation unit 113, and multiplexes the reference signal with the downlink data signal. Reference signals in the present specification include CRS (Common Reference Signal), CSI-RS (Channel State Information-Reference Signal), DMRS (De-Modulation Reference Signal), and the like. The signal allocation unit 104-1 outputs the transmission signal obtained by multiplexing the reference signal to the control information multiplexing unit 105-1.

  The control information multiplexer 105-1 receives a signal multiplexed with a reference signal, receives control information notified to the terminal device from the control information generator 112, and multiplexes a data signal multiplexed with the control information and the reference signal. To do. Control information multiplexing section 105-1 inputs a signal obtained by multiplexing the control signal to IFFT section 106-1. Here, the resource for multiplexing the control information is assumed to be one of a plurality of candidates (SS (Search Space)) determined by C-RNTI which is a user-specific ID. Details of SS will be described later.

  IFFT section 106-1 receives a signal obtained by multiplexing control signals from control information multiplexing section 105-1, and converts the input signal from a frequency domain signal sequence to a time domain signal sequence by performing inverse fast Fourier transform. To do. The time domain signal sequence is input to the transmission processing unit 107-1. The transmission processing unit 107-1 inserts a CP (Cyclic Prefix) in the time domain signal sequence, converts the signal into an analog signal by D / A (Digital / Analog) conversion, and converts the signal after the conversion. Upconvert the signal to the radio frequency used for transmission. The transmission processing unit 107-1 amplifies the upconverted signal with a PA (Power Amplifier), and transmits the amplified signal via the transmission antenna 108-1. The transmitting antennas 108-1 to 108-M from the encoding units 102-1 to 102-M perform the same processing as described above.

  FIG. 3 is a schematic block diagram showing an example of the configuration of a conventional terminal device. In the figure, N is the number of receiving antennas used for data reception. N is an integer of 1 or more. The receiving antennas 201-1 to 201-N receive signals transmitted from the base station apparatus, and input the received signals to the reception processing units 202-1 to 202-N. Subsequently, the reception processing units 202-2 to 202-N to the allocation signal extraction units 206-2 to 206-N perform the same processing as the blocks of the reception processing unit 202-1 to the allocation signal extraction unit 206-1, respectively. Therefore, only the processing from the reception processing unit 202-1 to the allocation signal extraction unit 206-1 will be described.

  The reception processing unit 202-1 down-converts the signal received by the reception antenna 201-1 to a baseband frequency, and performs A / D (Analog / Digital) conversion on the down-converted signal. Generate a digital signal. Further, the reception processing unit 202-1 removes the CP from the digital signal, and inputs the received signal sequence from which the CP has been removed to the FFT unit 203-1.

  The FFT unit 203-1 converts the input received signal sequence from a time domain signal sequence to a frequency domain signal sequence by fast Fourier transform, and inputs the frequency domain signal sequence to the reference signal separation unit 204-1. The reference signal separation unit 204-1 separates the reference signal sequence from the input frequency domain signal sequence. The reference signal separation unit 204-1 inputs the separated reference signal sequence to the propagation path estimation unit 212, and inputs the remaining received signal sequence obtained by separating the reference signal sequence to the control information separation unit 205-1.

  The propagation path estimation unit 212 estimates the frequency response of the propagation path based on a reference signal sequence known by the transmission / reception apparatus input from the reference signal separation units 204-1 to 204-N. The propagation path estimation unit 212 inputs the estimated frequency response to the control information generation unit 213 and the MIMO separation unit 208. The control information generation unit 213 uses the estimated channel frequency response when notifying the base station apparatus of CSI.

  On the other hand, the control information demultiplexing unit 205-1 separates the frequency domain signal sequence from which the reference signal sequence is separated into a PDCCH signal sequence (control signal sequence) and a PDSCH signal sequence (data signal sequence), and a PDCCH signal sequence Is input to the control information detection unit 216, and the PDSCH signal sequence is input to the allocation signal extraction unit 206-1. Also, when receiving the control information of RRC signaling, the control information separation unit 205-1 separates it as control information and inputs it to the control information detection unit 216. However, when the C-RNTI is received by RRC signaling, the control information separation unit 205-1 inputs the identifier storage unit 217. The identifier storage unit 217 stores the input C-RNTI.

  The control information detector 216 receives the PDCCH signal sequence from the control information separators 205-1 to 205-N. Further, the C-RNTI notified from the base station apparatus is held in the identifier storage unit 217, and the C-RNTI is also input to the control information detection unit 216. A schematic block diagram showing an example of the configuration of the control information detection unit 216 is shown in FIG. The control information detection unit 216 inputs the C-RNTI input from the identifier storage unit 217 to the CCE calculation unit 2161 and the CRC calculation unit 2164. In control information detection section 216, the PDCCH signal sequence input from control information separation sections 205-1 to 205-N is input to control information decoding section 2162. The CCE calculation unit 2161 calculates the index of the resource to be blind-decoded from the input C-RNTI, further extracts the length of the signal to be decoded from a predetermined table, and these information is the control information decoding unit 2162 To enter. Specifically, the position where SS performs blind decoding is determined by the following equation.

... Formula (1)

Where Lε {1, 2, 4, 8} is an aggregation level, N _{CCE, k} is the total number of CCEs (Control Channel Elements) in a subframe, and i is 0 ≦ i ≦ L−1. floor (·) is a floor function, and m ′ is defined by the following equation.

... Formula (2)

However, M ^(L) is the number of PDCCH candidates defined in Table 1 of FIG. 18, m is 0 ≦ m ≦ M ^(L) −1, n _CI is the Carrier Indicator Field Value, and the terminal device If this field is not set, n _CI = 0. Y _k is defined by the following equation.

... Formula (3)

However, k is floor (n _s / 2), and n _s is the slot number in the frame, D = 65537, and A = 39827. Since the initial value Y ₋₁ = n _RNTI ≠ 0 and n _RNTI is C-RNTI, SS differs for each user. Moreover, although _Yk is calculated by USS (UE-specific SS) by Formula (3), there is also a CSS (Common SS) that is common to all users. In this case, Y _k = 0.

  Control information decoding section 2162 decodes the PDCCH signal sequence based on the input index and signal length. Control information decoding section 2162 inputs the decoded signal to error determination section 2163, and inputs the CRC bit string added to the control information to CRC calculation section 2164.

  The CRC calculation unit 2164 performs an exclusive OR (XOR) operation on the input CRC bit string and C-RNTI, and inputs the bit string of the operation result to the error determination unit 2163. Here, since C-RNTI is an identifier uniquely assigned to each user, each terminal can detect only control information addressed to itself. The error determination unit 2163 determines whether or not there is an error by CRC with respect to the control information after decoding. When it is determined that there is no error, the error determination unit 2163 inputs the frequency resource allocation to the allocation signal extraction units 206-1 to 206-N in FIG. Further, although not shown, error determination section 2163 also inputs information such as MCS to demodulation sections 208-1 to 208-C and decoding sections 209-1 to 209-C in FIG. When an error is detected, the error determination unit 2163 notifies the CCE calculation unit 2161. In this case, the CCE calculation unit 2161 calculates another candidate for SS and inputs it to the control information decoding unit 2162. In this way, the control information detection unit 216 detects control information by blind decoding in which SS candidates are decoded a predetermined number of times.

  Returning to FIG. 3, allocation signal extraction section 206-1 receives frequency resource allocation information from control information detection section 216, extracts a data signal sequence transmitted from the base station apparatus from the frequency domain signal sequence, and performs MIMO separation. Input to the unit 208. The MIMO separation unit 208 generates an equalization weight based on the MMSE standard from the frequency response of the propagation channel input from the propagation channel estimation unit 212, and multiplies the input frequency domain data signal sequence by the weight. A MIMO multiplexed signal is separated. The MIMO separation unit 208 inputs the separated signal sequence to the demodulation units 209-1 to 209-C. However, C is an integer of 1 or more. For signal processing in the MIMO separation unit 208, other standard spatial filtering such as ZF (Zero Forcing) standard or other detection methods such as MLD (Maximum Likelihood Detection) may be applied.

  Demodulation sections 209-1 to 209 -C perform demodulation processing on the received signal sequence in the frequency domain according to the modulation scheme information notified by PDCCH, and perform bit sequence LLR (Log Likelihood Ratio), that is, LLR sequence Get. Demodulation sections 209-1 to 209-C output the LLR sequence obtained by the demodulation to decoding sections 210-1 to 210-C. Decoding sections 210-1 to 210-C perform a decoding process on the LLR sequence input according to the coding rate information notified by PDCCH. Error determination sections 211-1 to 211 -C make a hard decision on the input decoded LLR sequence for each codeword, and if there is no error, obtain a bit sequence as transmission data. In addition, the presence / absence of an error is input to the control information generation unit 213.

  The control information generation unit 213 receives A / N information to be notified to the base station apparatus from the error determination units 211-1 to 211 -C, and estimates from the reference signal sequence from the propagation path estimation unit 212 when transmitting CSI. The propagation path information is input. The control information generation unit 213 converts the input information into a PUCCH format signal that is control information of uplink (communication from the terminal device to the base station device), and inputs the control signal sequence to the control information transmission unit 214 To do. The control information transmission unit 214 amplifies the control signal sequence input from the control information generation unit 213 to a predetermined transmission power, and then transmits it via the transmission antenna 215.

  Here, FIG. 3 illustrates a terminal apparatus that receives data having a codeword number C from the base station apparatus, but C is an integer of 1 or more. When the base station device spatially multiplexes data addressed to a plurality of terminal devices by MU-MIMO transmission, and the terminal device receives one codeword data (C = 1), the terminal device may receive a request from the MIMO separation unit 208. Only the signal is extracted, and the data signal is detected by performing processing from the demodulating unit 209-1 to the error determining unit 211-1. Also, MIMO separation section 208 is notified of the number of antenna ports used for data transmission notified by control information from control information detection section 216, and this antenna port information is input.

(First embodiment)
In the first embodiment of the present invention, reception of a signal in which data of a plurality of terminal apparatuses is spatially multiplexed by MU-MIMO from a base station apparatus when the terminal apparatus can cancel interference by SIC will be described. In the conventional terminal device, in order to detect control information of other terminal devices multiplexed by MU-MIMO, the SS is different for each terminal device and the C-RNTI used for the blind decoding error determination is also unique to the terminal device. Therefore, a huge amount of blind decoding is required. Therefore, in the present embodiment, an example will be described in which USS is matched with another terminal device to be paired, and C-RNTI of another terminal device to be paired with MU-MIMO is notified.

  FIG. 5 is a schematic block diagram showing an example of the configuration of the base station apparatus according to the first embodiment of the present invention. The difference between FIG. 2 and FIG. 2 which is a configuration example of the conventional base station apparatus is only the scheduling unit 311, the control information generation unit 312, and the control information multiplexing units 305-1 to 305-M. Since others are the same, description is abbreviate | omitted.

The scheduling unit 311 receives CSI received from a plurality of terminal apparatuses, selects a terminal apparatus that transmits downlink data at the next transmission timing, and determines frequency resource allocation. Here, the scheduling unit 311 also determines a combination of terminal devices to be paired when performing MU-MIMO transmission. The paired terminal device is notified of the MU-RNTI that determines the SS to be blind-decoded in common by the paired terminal device and the I _other which is the C-RNTI of the _other paired terminal device. . Therefore, the scheduling unit 311 inputs I _other and MU-RNTI to the control information generating unit 312.

The control information generation unit 312 converts the input communication parameter into a control information format for each terminal device that notifies the communication parameter, and inputs the generated control information format to the control information multiplexing units 105-1 to 105-M. Here, in the present embodiment, when transmitting the data signal sequence by MU-MIMO transmission, the control information generation unit 312 assumes that the same control information format is used for all terminal apparatuses multiplexed by MU-MIMO transmission. Will be described. That is, all terminal apparatuses multiplexed by MU-MIMO transmission will be described assuming the same transmission mode. The control information generation unit 312 also inputs control information by RRC to the control information multiplexing units 105-1 to 105-M at the timing of notifying C-RNTI, MU-RNTI, and I _other notified by RRC signaling.

In this embodiment, the base station apparatus performs MU-MIMO transmission after notification _MU-RNTI from the RRC _signaling, the _{I other} to the terminal devices.

  FIG. 6 is a schematic block diagram showing an example of the configuration of the terminal device according to the first embodiment of the present invention. The difference between FIG. 3 and FIG. 3 which is a configuration example of a conventional terminal device is that control information separation units 405-1 to 405-N, control information detection unit 416 and identifier storage unit 417, cancel processing unit 407, and MIMO separation unit 408 , Demodulation units 409-1 to 409 -P, decoding units 410-1 to 410 -P, error determination units 411-1 to 411 -P, symbol replica generation units 418-1 to 418 -P, soft replica generation unit 419- 1 to 419-P. Since others are the same, description is abbreviate | omitted.

First, the control information separators 405-1 to 405-N separate the frequency domain signal sequence from which the reference signal sequence is separated into a PDCCH signal sequence (control signal sequence) and a PDSCH signal sequence (data signal sequence), The PDCCH signal sequence is input to the control information detection unit 416, and the PDSCH signal sequence is input to the allocation signal extraction units 206-1 to 206-N. Also, when control information of RRC signaling is received, the control information separation units 405-1 to 405-N separate the control information and input to the control information detection unit 416. However, C-RNTI by RRC signaling, when receiving the MU-RNTI and _{I other,} the control information separating unit 405-1~405-N is input to the identifier storage unit 417. The identifier storage unit 417 stores the input C-RNTI, MU-RNTI, and I _other .

FIG. 7 is a schematic block diagram showing an example of the configuration of the control information detection unit 416 according to the first embodiment of the present invention. The control information detector 416 receives a PDCCH signal sequence from the control information separators 405-1 to 405-N. Further, the C-RNTI, MU-RNTI and I _other notified from the base station apparatus are held in the identifier storage unit 417, and the MU-RNTI is input to the CCE calculation unit 4161, and the C-RNTI, MU-RNTI and All of the I _other are input to the identifier selection unit 4165. CCE calculator 4161 is supplied with the _{n MU-RNTI} is MU-RNTI, it calculates the position of blind decoding a USS. The calculation method uses equations (1) to (3) as in the conventional method, but only the initial value of equation (3) is different, and the following equation is obtained.

... Formula (4)

Equation (4) means that the same n _MU-RNTI is notified to other terminal devices paired by MU-MIMO, and the USS completely matches. The CCE calculation unit 4161 calculates the index of the resource to be blind-decoded as described above, further extracts the length of the signal to be decoded from a predetermined table, and inputs this information to the control information decoding unit 4162 . The control information decoding unit 4162 decodes the PDCCH signal sequence based on the input index and signal length. Control information decoding section 4162 inputs the decoded signal to error determination section 4163, and inputs the CRC bit string added to the control information to CRC calculation section 4164.

The identifier selection unit 4165 inputs the C-RNTI to the CRC calculation unit 4164 at the first error determination of the decoded signal. The CRC calculation unit 4164 performs an exclusive OR operation on the input CRC bit string and C-RNTI, and inputs the result to the error determination unit 4163. The error determination unit 4163 checks whether or not the PDCCH control information addressed to the local station can be decoded without error. Here, when it is determined that there is no error, it is processed as PDCCH control information addressed to the own station as in the conventional case. When an error is detected, the error determination unit 4163 inputs error detection information to the identifier selection unit 4165. The identifier selection unit 4165 inputs I _other information which is C-RNTI of another terminal device paired to the CRC calculation unit 4164 at the time of the second error determination. The CRC calculation unit 4164 performs an exclusive OR operation on the input CRC bit string and I _other and inputs the result to the error determination unit 4163. The error determination unit 4163 checks whether or not the PDCCH control information addressed to another paired terminal device has been decoded without error. If it is determined that there is no error, it is determined that data has been received by MU-MIMO transmission, and the detected PDCCH is output for use in interference cancellation processing. The PDCCH control information addressed to other paired terminal devices is input to the allocation signal extraction units 206-1 to 206-N in FIG. Although not shown, the MCS information included in the PDCCH control information addressed to other paired terminal devices includes the demodulation units 208-1 to 208 -C and decoding units 209-1 to 209-in FIG. C is input. When an error is detected in both C-RNTI and I _other , the error determination unit 4163 notifies the CCE calculation unit 4161. In this case, the CCE calculation unit 4161 calculates another candidate for SS and inputs it to the control information decoding unit 4162. In this manner, the control information detection unit 416 detects control information by blind decoding that decodes SS candidates a predetermined number of times.

FIG. 8 is an example of a flowchart relating to blind decoding in the present embodiment. In step S10, if the number of times of blind decoding, which is the number of times control information is decoded at a specific reception timing, is within a predetermined value, the process proceeds to step S11, and if the number of blind decoding exceeds a predetermined value, the process ends. . In step S11, the CCE calculation unit 4161 calculates a position (index) where USS blind decoding is performed using Expressions (1) to (4), and outputs the index and the length of the signal. In step S12, the PDCCH signal sequence is decoded based on the index and the signal length input in control information decoding section 4162. In step S13, an error determination is performed on the CRC bit string and the C-RNTI using a bit string obtained by exclusive OR operation. If an error is detected, the process proceeds to step S14. If no error is detected, step S15 is performed. Migrate to In step S14, an error determination is performed on the CRC bit string and I _other by a bit string obtained by exclusive OR operation. If an error is detected, the process returns to step S10, and if the number of blind decoding is within a predetermined value. The CCE of another candidate for SS is calculated. If no error is detected, the process proceeds to step S15. In step S15, when the control information is detected by both C-RNTI and _Iother , the process ends. If only one of the control information is detected, the process returns to step S10. As described above, control information is detected in MU-MIMO transmission.

  The cancel processing unit 407 in FIG. 6 performs cancel processing when a soft replica is input from the soft replica generation units 419-1 to 419 -P. Where P is the number of code words. If no soft replica is entered, nothing is done. The MIMO separation unit 408 receives the antenna port information from which the signal addressed to itself is transmitted from the control information detection unit 416 and the antenna port information used for data transmission of other terminal devices paired with MU-MIMO. Then, the signal is separated by the propagation path estimation unit 212 based on the frequency response for each antenna port. For signal separation, equalization weights based on the MMSE norm may be used, or other detection methods such as spatial filtering of other criteria such as ZF criteria, or MLD (Maximum Likelihood Detection) may be applied. .

  The subsequent processing will be described on the premise of SIC processing which is a non-iterative IC receiver. First, the demodulation units 409-1 to 409 -P are paired based on the modulation multilevel number included in the MCS of another terminal device paired by MU-MIMO detected by the control information detection unit 416. A signal from another terminal apparatus is demodulated to obtain an LLR sequence. Here, P is the number of codewords of another terminal device. Decoding sections 410-1 to 410 -P perform decoding processing on the input LLR sequence based on the coding rate included in the MCS of another terminal device paired by MU-MIMO. In the case where the input decoded LLR sequence is a signal of another terminal device paired by MU-MIMO, error determination sections 411-1 to 411 -P send to symbol replica generation sections 418-1 to 418 -P. Input the decoded LLR sequence. The symbol replica generation units 418-1 to 418 -P convert the decoded LLR sequences into symbol replicas according to the modulation multilevel number used for data transmission of other terminal apparatuses, and the soft replica generation units 419-1 to 419-1. Input to 419-P. The soft replica generation units 419-1 to 419 -P calculate a soft replica by multiplying the estimated frequency response, and input the soft replica to the cancellation processing unit 407. Next, the signal after interference cancellation is input from the cancel processing unit 407 to the MIMO separation unit 408. The MIMO separation unit 408 detects a signal addressed to the own station and inputs it to the demodulation units 409-1 to 409 -P. Here, P is the number of code words of the signal addressed to the own station. In this specification, for simplicity of explanation, the number of codewords is the same as that of other terminal devices paired by MU-MIMO, but the number of codewords may be different for each terminal device. The LLR sequence obtained after the demodulation process and the decoding process is hard-determined for each codeword by the error determination units 411-1 to 411 -P, and an error determination is made. If there is no error, a bit string is obtained as transmission data. In addition, the presence / absence of an error is input to the control information generation unit 213.

In the present embodiment, the number of users multiplexed by MU-MIMO has been described as u = 2. However, the number of users u multiplexed by MU-MIMO may be 3 or more. In that case, it suffices to notify only u−1 that is the C-RNTI I _other of another terminal device paired by MU-MIMO, and the number of blind decoding can be realized in the same manner as u = 2. The processing from the cancellation processing unit 407 to the error determination units 411-1 to 411 -P is performed for each user multiplexed by MU-MIMO, but is ordered according to information on propagation path characteristics, MCS, number of codewords, and the like. May be. In the present embodiment, the SIC process that is a non-iterative IC receiver is assumed. However, the present invention can also be applied to turbo equalization and turbo SIC that are iterative IC receivers. In this case, if an error is detected by the error determination units 411-1 to 411-P after detecting the signal addressed to the own station, the symbol replica generation units 418-1 to 418-P and the soft replica generation unit 419- 1 to 419-P can generate a soft replica of a signal addressed to the own station, detect a signal of another terminal device paired with MU-MIMO again, and obtain a highly accurate interference signal replica . It is possible to improve the error rate characteristics by detecting a signal addressed to the own station again using this highly accurate replica of the interference signal. In the downlink, a transmission mode is set for each terminal device, and MU-MIMO transmission is possible only in a specific transmission mode. Therefore, the terminal device may detect the control information described in the present embodiment only when a transmission mode capable of MU-MIMO transmission is set. Moreover, although this embodiment demonstrated as all the terminals multiplexed by MU-MIMO having the same transmission mode set, different transmission modes may be set. Moreover, although the base station apparatus of this embodiment demonstrated that all the terminals multiplexed by MU-MIMO notify control information by the same DCI format, you may notify by a different DCI format. In that case, the terminal apparatus performs blind decoding of a different DCI format.

  As described above, in the present embodiment, when the base station apparatus performs downlink data transmission by MU-MIMO transmission and the terminal apparatus can cancel interference by SIC, the SS of the terminal apparatus paired by MU-MIMO is set. The matched signal and the C-RNTI of another terminal device paired by MU-MIMO are notified. Thereby, it is possible to detect control information of other terminal apparatuses paired by MU-MIMO without increasing the number of times of blind decoding. As a result, when a terminal device detects a desired signal, it can detect a signal of another terminal device paired by MU-MIMO and use it for interference cancellation, thereby improving error rate characteristics and throughput. Is possible.

(Second Embodiment)
In the second embodiment of the present invention, reception of data transmitted from the base station apparatus by MU-MIMO transmission is described, in which the terminal apparatus can receive data by SIC as in the previous embodiment. In the conventional terminal device, in order to detect control information of other terminal devices multiplexed by MU-MIMO, the SS is different for each terminal device and the C-RNTI used for the blind decoding error determination is also unique to the terminal device. Therefore, a huge amount of blind decoding is required. Therefore, in the present embodiment, an example in which C-RNTI common to other terminal devices paired separately from user-specific C-RNTI is notified and control information is notified using the common C-RNTI is described. To do.

  FIG. 9 shows a schematic block diagram illustrating an example of the configuration of the base station apparatus according to the second embodiment of the present invention. The difference between FIG. 5 and FIG. 5 that is a configuration example of the base station apparatus according to the first embodiment is only the scheduling unit 511 and the control information generation unit 512. Since others are the same, description is abbreviate | omitted.

  The scheduling unit 511 receives CSI received from a plurality of terminal apparatuses, selects a terminal apparatus that transmits downlink data at the next transmission timing, and determines frequency resource allocation. Here, the scheduling unit 511 also determines a combination of terminal devices to be paired when performing MU-MIMO transmission. The paired terminal device is notified of the MU-RNTI that determines the SS to be blind-decoded in common with the other paired terminal devices. Therefore, the scheduling unit 511 inputs the MU-RNTI to the control information generation unit 512.

  The control information generation unit 512 converts the input communication parameter into a control information format for each terminal device that notifies the input communication parameter, and inputs the generated control information format to the control information multiplexing units 105-1 to 105-M. In addition, the control information generation unit 512 also inputs control information by RRC to the control information multiplexing units 105-1 to 105-M at the timing of notification of C-RNTI or MU-RNTI notified by RRC signaling. In this embodiment, MU-MIMO transmission is performed after notifying MU-RNTI from RRC signaling.

  In addition to the control information described above, the control information generation unit 512 generates control information for MU-MIMO transmission including control information of paired terminal devices in the present embodiment, and generates control information multiplexing units 105-1 to 105-1. Input to 105-M. The control information for MU-MIMO transmission is specifically information such as frequency resource allocation, MCS, and antenna port used by the terminal device for SIC reception, and includes information on all paired terminal devices. . Here, in the present embodiment, it is assumed that the control information for notifying the communication parameter input from the scheduling unit 511 and the control information for MU-MIMO transmission including the control information of the paired terminal device have the same size. explain.

  FIG. 10 is a schematic block diagram showing an example of the configuration of the terminal device according to the second embodiment of the present invention. The difference between FIG. 6 and FIG. 6, which is a configuration example of a conventional terminal device, is a control information separation unit 605-1 to 605-N, a control information detection unit 616, and an identifier storage unit 617. Since others are the same, description is abbreviate | omitted.

  First, in the control information separation units 605-1 to 605-N, the frequency domain signal sequence from which the reference signal sequence is separated is separated into a PDCCH signal sequence (control signal sequence) and a PDSCH signal sequence (data signal sequence), The PDCCH signal sequence is input to the control information detection unit 616, and the PDSCH signal sequence is input to the allocation signal extraction units 206-1 to 206-N. Also, when control information of RRC signaling is received, the control information separation units 605-1 to 605-N separate the control information and input to the control information detection unit 616. However, when C-RNTI or MU-RNTI is received by RRC signaling, the control information separation units 605-1 to 605-N input the identifier storage unit 617. The identifier storage unit 617 stores the input C-RNTI and MU-RNTI.

  FIG. 11 is a schematic block diagram showing an example of the configuration of the control information detection unit 616 according to the first embodiment of the present invention. The control information detector 616 receives a PDCCH signal sequence from the control information separators 605-1 to 605-N. Further, the C-RNTI and MU-RNTI notified from the base station apparatus are held in the identifier storage unit 617, the MU-RNTI is input to the CCE calculation unit 4161, and the C-RNTI and MU-RNTI are the identifier selection unit. 6165. Similar to the first embodiment, the CCE calculation unit 4161 calculates the position of the blind decoding of the USS, further extracts the length of the signal to be decoded from a predetermined table, and decodes these pieces of information as control information decoding Input to the unit 4162. The control information decoding unit 4162 decodes the PDCCH signal sequence based on the input index and signal length. Control information decoding section 4162 inputs the decoded signal to error determination section 4163 and inputs the CRC bit string added to the control information to CRC calculation section 6164.

  The identifier selection unit 6165 inputs the C-RNTI to the CRC calculation unit 6164 at the first error determination of the decoded signal. The CRC calculation unit 6164 performs an exclusive OR operation on the input CRC bit string and C-RNTI, and inputs the result to the error determination unit 4163. The error determination unit 4163 checks whether or not the PDCCH control information addressed to the local station can be decoded without error. Here, when it is determined that there is no error, it is processed as PDCCH control information addressed to the own station as in the conventional case. When an error is detected, the error determination unit 4163 inputs error detection information to the identifier selection unit 6165. The identifier selection unit 6165 inputs the MU-RNTI to the CRC calculation unit 6164 at the time of the second error determination. The CRC calculation unit 6164 performs an exclusive OR operation on the input CRC bit string and MU-RNTI, and inputs the result to the error determination unit 4163. The error determination unit 4163 checks whether the control information for MU-MIMO transmission can be decoded without error. If it is determined that there is no error, it is determined that data has been received by MU-MIMO transmission, and the detected PDCCH is output for use in interference cancellation processing. The frequency resource allocation of the control information of the other paired terminal devices included in the control information for MU-MIMO transmission is input to allocation signal extraction sections 206-1 to 206-N. In addition, although not shown, the information of the MCS of the other paired terminal devices is input to the demodulation units 208-1 to 208-C and the decoding units 209-1 to 209-C. If an error is detected in both C-RNTI and MU-RNTI, error determination unit 4163 notifies CCE calculation unit 4161. In this case, the CCE calculation unit 4161 calculates another candidate for SS and inputs it to the control information decoding unit 4162. In this manner, the control information detection unit 416 detects control information by blind decoding that decodes SS candidates a predetermined number of times.

  FIG. 12 is an example of a flowchart relating to blind decoding in the present embodiment. Steps S10 to S13 are the same as those in the first embodiment, and a description thereof will be omitted. In step S14, the CRC bit string and the MU-RNTI are subjected to error determination using the bit string obtained by the exclusive OR operation, and it is checked whether the control information for MU-MIMO transmission can be decoded without error. If an error is detected, the process returns to step S10. If no error is detected, the process proceeds to step S25. In step S25, when control information is detected by both C-RNTI and MU-RNTI, the process ends. If only one of the control information is detected, the process returns to step S10. As described above, control information is detected in MU-MIMO.

  In the present embodiment, the number of users multiplexed by MU-MIMO has been described as u = 2. However, the number of users u multiplexed by MU-MIMO may be 3 or more. In that case, the base station apparatus may notify control information necessary for SIC reception of all terminal apparatuses paired by MU-MIMO by using control information for MU-MIMO transmission, and the number of times of blind decoding is u = 2. The same can be realized. The processing from the cancellation processing unit 407 to the error determination units 411-1 to 411 -P is performed for each user multiplexed by MU-MIMO, but is ordered according to information on propagation path characteristics, MCS, number of codewords, and the like. May be. In the present embodiment, the SIC process that is a non-iterative IC receiver is assumed. However, the present invention can also be applied to turbo equalization and turbo SIC that are iterative IC receivers. In this case, if an error is detected by the error determination units 411-1 to 411-P after detecting the signal addressed to the own station, the symbol replica generation units 418-1 to 418-P and the soft replica generation unit 419- 1 to 419-P can generate a soft replica of a signal addressed to the own station, detect a signal of another terminal device paired with MU-MIMO again, and obtain a highly accurate interference signal replica . It is possible to improve the error rate characteristics by detecting a signal addressed to the own station again using this highly accurate replica of the interference signal. In the downlink, a transmission mode is set for each terminal device, and MU-MIMO transmission is possible only in a specific transmission mode. Therefore, the terminal device may detect the control information described in the present embodiment only when a transmission mode capable of MU-MIMO transmission is set. Further, in the present embodiment, the control information generation unit 512 has the same control information for MU-MIMO transmission including the control information for notifying the communication parameter input from the scheduling unit 511 and the control information of the paired terminal device. Although described as a size, it may be generated in a different size. In that case, the terminal apparatus performs blind decoding of control information of different sizes.

  As described above, in the present embodiment, when the base station apparatus performs downlink data transmission by MU-MIMO transmission and the terminal apparatus can cancel interference by SIC, the SS of the terminal apparatus paired by MU-MIMO is set. A signal to be matched and a control necessary for SIC reception of another terminal device paired by MU-MIMO are notified. Thereby, it is possible to detect control information of other terminal apparatuses paired by MU-MIMO without increasing the number of times of blind decoding. As a result, when a terminal device detects a desired signal, it can detect a signal of another terminal device paired by MU-MIMO and use it for interference cancellation, thereby improving error rate characteristics and throughput. Is possible.

(Third embodiment)
In the third embodiment of the present invention, reception of data transmitted from the base station apparatus by MU-MIMO transmission is described, in which the terminal apparatus can receive data by SIC as in the previous embodiment. In the conventional terminal device, in order to detect control information of other terminal devices multiplexed by MU-MIMO, the SS is different for each terminal device and the C-RNTI used for the blind decoding error determination is also unique to the terminal device. Therefore, a huge amount of blind decoding is required. Therefore, in this embodiment, an example will be described in which common control information is notified to all terminal devices paired by MU-MIMO.

  FIG. 13 is a schematic block diagram showing an example of the configuration of the base station apparatus according to the third embodiment of the present invention. The difference between FIG. 9 and the configuration example of the base station apparatus of the second embodiment in FIG. 9 is only the control information generation unit 712. Since others are the same, description is abbreviate | omitted.

  In the case of a terminal device that does not perform MU-MIMO transmission, the control information generation unit 712 converts the input communication parameter into a control information format for each terminal device that notifies the communication parameter, and converts the generated control information format to the control information multiplexing units 105-1 to 105-1. Input to 105-M. In the case of a terminal device that performs MU-MIMO transmission, the control information generation unit 712 converts communication parameters to be notified to all paired terminal devices into one control information format, and the generated control information format is the control information multiplexing unit 105. -1 to 105-M. In addition, the control information generation unit 712 also inputs control information by RRC to the control information multiplexing units 105-1 to 105-M at the timing of notifying C-RNTI or MU-RNTI notified by RRC signaling. In this embodiment, MU-MIMO transmission is performed after notifying MU-RNTI from RRC signaling.

  As specific examples including communication parameters to be notified to all terminal devices paired in one control information format, terminals such as MCS, NDI (New Data Indicator), RV (Redundancy Version), antenna port information, PUCCH TPC, etc. The format includes a plurality of pieces of device-specific information and only one parameter common to the terminal device. The parameters common to the terminal devices may share frequency resource allocation or the like, or may share the SRS transmission request (SRS request).

  Configuration examples of the terminal device and the control information detection unit according to the third embodiment of the present invention are the same as those in FIGS. 3 and 4. However, the processing of the CRC calculation unit included in the control information detection unit is different.

  FIG. 14 is an example of a flowchart relating to blind decoding in the present embodiment. Steps S <b> 10 to S <b> 12 are the same as in the second embodiment, and a description thereof is omitted. In step S33, the CRC bit string and the MU-RNTI are subjected to error determination using the bit string obtained by exclusive OR operation, and the format including the control information of all the terminal devices paired by MU-MIMO has been decoded without error. Check. If an error is detected, the process returns to step S10. If no error is detected, the control information addressed to the own station and the control information of other terminals paired by MU-MIMO are detected at the same time, and the process ends. As described above, control information is detected in MU-MIMO.

  The present embodiment is applicable if the number of users u multiplexed by MU-MIMO is 2 or more. In that case, it is only necessary to notify the control information of all terminal devices paired in one control information format, and this can be realized without increasing the number of times of blind decoding. The processing from the cancellation processing unit 407 to the error determination units 411-1 to 411 -P is performed for each user multiplexed by MU-MIMO, but is ordered according to information on propagation path characteristics, MCS, number of codewords, and the like. May be. In the present embodiment, the SIC process that is a non-iterative IC receiver is assumed. However, the present invention can also be applied to turbo equalization and turbo SIC that are iterative IC receivers. In this case, if an error is detected by the error determination units 411-1 to 411-P after detecting the signal addressed to the own station, the symbol replica generation units 418-1 to 418-P and the soft replica generation unit 419- 1 to 419-P can generate a soft replica of a signal addressed to the own station, detect a signal of another terminal device paired with MU-MIMO again, and obtain a highly accurate interference signal replica . It is possible to improve the error rate characteristics by detecting a signal addressed to the own station again using this highly accurate replica of the interference signal. In the downlink, a transmission mode is set for each terminal device, and MU-MIMO transmission is possible only in a specific transmission mode. Therefore, the terminal device may detect the control information described in the present embodiment only when a transmission mode capable of MU-MIMO transmission is set.

  As described above, in the present embodiment, when the base station apparatus performs downlink data transmission by MU-MIMO transmission and the terminal apparatus can cancel interference by SIC, the SS of the terminal apparatus paired by MU-MIMO is set. A signal to be matched and a control necessary for SIC reception of another terminal device paired by MU-MIMO are notified. Thereby, it is possible to detect control information of other terminal apparatuses paired by MU-MIMO without increasing the number of times of blind decoding. As a result, when a terminal device detects a desired signal, it can detect a signal of another terminal device paired by MU-MIMO and use it for interference cancellation, thereby improving error rate characteristics and throughput. Is possible.

(Fourth embodiment)
In the fourth embodiment of the present invention, reception of data transmitted from the base station apparatus by MU-MIMO transmission is described, in which the terminal apparatus can receive data by SIC as in the previous embodiment. In the conventional terminal device, since C-RNTI used for the blind decoding error determination is a value unique to the terminal device, control information of other terminal devices multiplexed by MU-MIMO cannot be detected. Therefore, in the present embodiment, an example will be described in which control information of another terminal device paired with MU-MIMO is detected.

  The configuration example of the base station apparatus according to the fourth embodiment of the present invention is the same as that of FIG. FIG. 15 is a schematic block diagram showing an example of the configuration of a terminal device according to the fourth embodiment of the present invention. The difference between FIG. 10 and the configuration example of the terminal device according to the second embodiment in FIG. 10 is a control information separation unit 805-1 to 805-N, a control information detection unit 816, and an identifier storage unit 817. Since others are the same, description is abbreviate | omitted.

First, in the control information demultiplexing units 805-1 to 805-N, the frequency domain signal sequence from which the reference signal sequence is separated is separated into a PDCCH signal sequence (control signal sequence) and a PDSCH signal sequence (data signal sequence), The PDCCH signal sequence is input to the control information detection unit 816, and the PDSCH signal sequence is input to the allocation signal extraction units 206-1 to 206-N. Also, when control information of RRC signaling is received, the control information separation units 805-1 to 805-N separate the control information and input to the control information detection unit 816. However, when an I _other which is a C-RNTI of another terminal paired by C-RNTI or MU-MIMO is received by RRC signaling, the control information demultiplexing units 805-1 to 805-N are stored in the identifier storage unit 817. input. The identifier storage unit 817 stores the input C-RNTI and I _other .

FIG. 16 is a schematic block diagram showing an example of the configuration of the control information detection unit 816 according to the fourth embodiment of the present invention. The control information detection unit 816 receives the PDCCH signal sequence from the control information separation units 805-1 to 805-N. Furthermore, C-RNTI and _{I other} notified from the base station apparatus is held by the identifier storage unit 817, both the C-RNTI and _{I other} are inputted to the CCE calculator 8161, C-RNTI and _{I other} is It is also input to the identifier selection unit 8165. The CCE calculation unit 8161 calculates the position where blind decoding of the USS is performed using Expressions (1) to (3), further extracts the length of a signal to be decoded from a predetermined table, and extracts these pieces of information. The information is input to the control information decoding unit 8162. However, only the initial value of Expression (3) is different, and the following expression is obtained.

... Formula (5)

However, n _C-RNTI is the value of C-RNTI. The control information decoding unit 8162 decodes the PDCCH signal sequence based on the input index and signal length. Control information decoding section 8162 inputs the decoded signal to error determination section 8163, and inputs the CRC bit string added to the control information to CRC calculation section 8164.

  The identifier selection unit 8165 inputs the C-RNTI to the CRC calculation unit 8164. The CRC calculation unit 8164 performs an exclusive OR operation on the input CRC bit string and C-RNTI, and inputs the result to the error determination unit 8163. The error determination unit 8163 checks whether or not the PDCCH control information addressed to the local station can be decoded without error. Here, when it is determined that there is no error, it is processed as PDCCH control information addressed to the own station as in the conventional case. In addition, a notification that the PDCCH control information addressed to the own station is detected without error is input to the CCE calculation unit 8161 and the identifier selection unit 8165. When an error is detected, the CCE calculation unit 8161 calculates another candidate for SS and inputs it to the control information decoding unit 8162. In this way, the control information detection unit 816 detects control information by blind decoding in which SS candidates are decoded a predetermined number of times.

  Next, the CCE calculating unit 8161 detects the PDCCH control information addressed to the own station, calculates the position where the USS blind decoding is performed, using equations (1) to (3) and the following equation, and further decodes the position. The length of the signal is extracted from a predetermined table, and these pieces of information are input to the control information decoding unit 8162.

... Formula (6)

  The above means performing USS BD of another terminal device paired with MU-MIMO. The control information decoding unit 8162 decodes the PDCCH signal sequence based on the input index and signal length. Control information decoding section 8162 inputs the decoded signal to error determination section 8163, and inputs the CRC bit string added to the control information to CRC calculation section 8164.

The identifier selection unit 8165 inputs I _other to the CRC calculation unit 8164. The CRC calculation unit 8164 performs an exclusive OR operation on the input CRC bit string and I _other and inputs the result to the error determination unit 8163. The error determination unit 8163 checks whether the PDCCH control information addressed to another terminal device paired by MU-MIMO can be decoded without error. If it is determined that there is no error, it is determined that data has been received by MU-MIMO transmission, and the detected PDCCH is output for use in interference cancellation processing. The frequency resource allocation of the control information of the other paired terminal devices included in the control information for MU-MIMO transmission is input to allocation signal extraction sections 206-1 to 206-N. In addition, although not shown, the information of the MCS of the other paired terminal devices is input to the demodulation units 208-1 to 208-C and the decoding units 209-1 to 209-C. When an error is detected, the CCE calculation unit 8161 calculates another candidate for SS and inputs it to the control information decoding unit 8162. In this way, the control information detection unit 816 detects control information by blind decoding in which SS candidates are decoded a predetermined number of times.

FIG. 17 is an example of a flowchart relating to blind decoding in the present embodiment. Steps S <b> 10 to S <b> 12 are the same as in the first embodiment, and a description thereof will be omitted. In step S43, the CRC bit string and the C-RNTI are subjected to error determination using the bit string obtained by exclusive OR operation, and it is checked whether the control information addressed to the own station can be decoded without error. If an error is detected, the process returns to step S10. If no error is detected, the process proceeds to step S44. In step S44, if the number of times of blind decoding that is the number of times of decoding of control information addressed to other terminal devices paired by MU-MIMO is within a predetermined value, the process proceeds to step S45, where the number of times of blind decoding is predetermined. If it exceeds the value of, the process ends. In step S45, the CCE calculation unit 8161 calculates the position (index) for USS blind decoding using Expressions (1) to (3) and (6), and outputs the index and the length of the signal. In step S46, the PDCCH signal sequence is decoded based on the index and the signal length input in control information decoding section 8162. In step S47, error determination is performed on the CRC bit string and I _other by a bit string obtained by exclusive OR operation. If an error is detected, the process proceeds to step S44, and if no error is detected, the process ends. . As described above, in MU-MIMO, control information addressed to its own station and control information addressed to another terminal device paired in MU-MIMO are detected.

In the present embodiment, the number of users multiplexed by MU-MIMO has been described as u = 2. However, the number of users u multiplexed by MU-MIMO may be 3 or more. In that case, it suffices to notify only u−1 that is the C-RNTI I _other of another terminal device paired by MU-MIMO, and the number of blind decoding can be realized in the same manner as u = 2. The processing from the cancellation processing unit 407 to the error determination units 411-1 to 411 -P is performed for each user multiplexed by MU-MIMO, but is ordered according to information on propagation path characteristics, MCS, number of codewords, and the like. May be. In the present embodiment, the SIC process that is a non-iterative IC receiver is assumed. However, the present invention can also be applied to turbo equalization and turbo SIC that are iterative IC receivers. In this case, if an error is detected by the error determination units 411-1 to 411-P after detecting the signal addressed to the own station, the symbol replica generation units 418-1 to 418-P and the soft replica generation unit 419- 1 to 419-P can generate a soft replica of a signal addressed to the own station, detect a signal of another terminal device paired with MU-MIMO again, and obtain a highly accurate interference signal replica . It is possible to improve the error rate characteristics by detecting a signal addressed to the own station again using this highly accurate replica of the interference signal. In the downlink, a transmission mode is set for each terminal device, and MU-MIMO transmission is possible only in a specific transmission mode. Therefore, the terminal device may detect the control information described in the present embodiment only when a transmission mode capable of MU-MIMO transmission is set.

  As described above, in this embodiment, when the base station apparatus performs downlink data transmission by MU-MIMO transmission and the terminal apparatus can cancel interference by SIC, other terminal apparatuses paired by MU-MIMO By notifying C-RNTI, it becomes possible to detect control information of other terminals. As a result, when a terminal device detects a desired signal, it can detect a signal of another terminal device paired by MU-MIMO and use it for interference cancellation, thereby improving error rate characteristics and throughput. Is possible.

Note that the terminal device and a part of the base station device according to the above-described embodiment may be realized by a computer. In that case, the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed. The “computer system” here is a computer system built in a terminal device or a base station device, and includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” is a medium that dynamically holds a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, In such a case, a volatile memory inside a computer system serving as a server or a client may be included and a program that holds a program for a certain period of time. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.
Moreover, you may implement | achieve part or all of the terminal device or base station apparatus which concerns on embodiment mentioned above as integrated circuits, such as LSI (Large Scale Integration). Each functional block of the terminal apparatus or the base station apparatus may be individually made into a processor, or a part or all of them may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Further, in the case where an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology may be used.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

eNB ... base station apparatus UE1 to UE2 ... terminal apparatus 101-1 to 101-M ... retransmission control section 102-1 to 102-M ... encoding section 103-1 to 103-M ... modulation section 104-1 to 104-M ... Signal allocation units 105-1 to 105-M ... Control information multiplexing units 106-1 to 106-M ... IFFT units 107-1 to 107-M ... Transmission processing units 108-1 to 108-M ... Transmission antenna 109 ... Reception Antenna 110 ... Receiving unit 111 ... Scheduling unit 112 ... Control information generating unit 113 ... Reference signal generating unit 114 ... Precoding unit 201-1 to 201-N ... Receiving antenna 202-1 to 202-N ... Reception processing unit 203-1 ˜203-N FFT unit 204-1 to 204-N Reference signal separation unit 205-1 to 205-N Control information separation unit 206-1 to 206-N Allocation signal Extraction unit 208 ... MIMO separation unit 209-1 to 209 -C ... Demodulation unit 210-1 to 210 -C ... Decoding unit 211-1 to 211 -C ... Error determination unit 212 ... Propagation path estimation unit 213 ... Control information generation unit 214 ... Control information transmitting unit 215 ... Transmitting antenna 216 ... Control information detecting unit 217 ... Identifier storage unit 2161 ... CCE calculating unit 2162 ... Control information decoding unit 2163 ... Error determining unit 2164 ... CRC calculating unit 311 ... Scheduling unit 312 ... Control information Generation unit 405-1 to 405-N ... Control information separation unit 407 ... Cancel processing unit 408 ... MIMO separation unit 409-1 to 409-P ... Demodulation unit 410-1 to 410-P ... Decoding unit 411-1 to 411- P ... error determination unit 416 ... control information detection unit 417 ... identifier storage unit 418-1 to 418-P ... symbol replica generation 419-1 to 419 -P ... Soft replica generation unit 4161 ... CCE calculation unit 4162 ... Control information decoding unit 4163 ... Error determination unit 4164 ... CRC calculation unit 4165 ... Identifier selection unit 511 ... Scheduling unit 512 ... Control information generation unit 605- 1-605 -N: control information separation unit 616: control information detection unit 617 ... identifier storage unit 6164 ... CRC calculation unit 6165 ... identifier selection unit 712 ... control information generation unit 805-1-805 -N ... control information separation unit 816 ... Control information detection unit 817 ... Identifier storage unit 8161 ... CCE calculation unit 8162 ... Control information decoding unit 8163 ... Error determination unit 8164 ... CRC calculation unit 8165 ... Identifier selection unit

1 is a schematic diagram of a downlink of a cellular system according to the present invention. FIG. It is a schematic block diagram which shows an example of a structure of the conventional base station apparatus. It is a schematic block diagram which shows an example of a structure of the conventional terminal device. It is a schematic block diagram which shows an example of a structure of the control information detection part which concerns on 1st Embodiment. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on 1st Embodiment. It is a schematic block diagram which shows an example of a structure of the terminal device which concerns on 1st Embodiment. It is a schematic block diagram which shows an example of a structure of the control information detection part which concerns on 1st Embodiment. It is an example of the flowchart of the blind decoding which concerns on 1st Embodiment. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on 2nd Embodiment. It is a schematic block diagram which shows an example of a structure of the terminal device which concerns on 2nd Embodiment. It is a schematic block diagram which shows an example of a structure of the control information detection part which concerns on 2nd Embodiment. It is an example of the flowchart of the blind decoding which concerns on 2nd Embodiment. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on 3rd Embodiment. It is an example of the flowchart of the blind decoding which concerns on 3rd Embodiment. It is a schematic block diagram which shows an example of a structure of the terminal device which concerns on 4th Embodiment. It is a schematic block diagram which shows an example of a structure of the control information detection part which concerns on 4th Embodiment. It is an example of the flowchart of the blind decoding which concerns on 4th Embodiment. It is an example of the table | surface which shows the number of candidates of the conventional blind decoding.

Claims (9)

A terminal device that receives a data signal in which multicarrier signals from a base station device to a plurality of terminal devices are multiplexed at the same time and at the same frequency,
The terminal device includes a control information separation unit that separates at least one of parameters unique to another terminal device that multiplexes a signal from a received signal or a parameter that is common only between terminal devices that are multiplexed a data signal, and the parameter And a control information detecting unit that detects control information transmitted to the other terminal device based on any one of the terminal device.   The terminal device includes a demodulator that demodulates a multicarrier signal to the other terminal device based on the detected control information, and a cancel processor that cancels the demodulated multicarrier signal from a data signal. The terminal device according to claim 1.   2. The terminal apparatus according to claim 1, further comprising a CCE calculating unit that calculates a search space for detecting the control information transmitted to the other terminal apparatus based on any one of the parameters.   The terminal device according to claim 3, wherein the search space is a search space common to terminal devices in which transmission signals to a plurality of terminal devices are multiplexed.   The CRC calculation unit according to claim 1, further comprising: a CRC calculation unit that calculates a CRC used for an error check when detecting the control information transmitted to the other terminal device based on any one of the parameters. Terminal device.   The control information including simultaneously the control information used for receiving a desired data signal and the control information transmitted to the other terminal device is detected based on any one of the parameters. Terminal equipment. A base station device that multiplexes and transmits multicarrier signals to be transmitted to a plurality of terminal devices at the same time and the same frequency,
For the terminal device, at least one of the parameters unique to the other terminal device used for detection of control information transmitted to another terminal device that multiplexes the data signal or a parameter that is common only between the terminal devices multiplexed with the data signal A base station apparatus that performs notification.   The base station apparatus according to claim 6, wherein any one of the parameters is a parameter for determining a search space for detecting the control information transmitted to the other terminal apparatus.   The base station apparatus according to claim 6, wherein any one of the parameters is a parameter for calculating a CRC used for error checking when detecting the control information transmitted to the other terminal apparatus.