JP2010512099A - Method and apparatus for transmitting and receiving data and control information through uplink in wireless communication system - Google Patents

Abstract

  The present invention provides a method and apparatus for multiplexing and transmitting data and uplink control information and receiving the data and control information in a wireless communication system. In a system that multiplexes an uplink packet data channel and a control channel, the transmission format of the control channel for transmission of control information is changed according to the transmission format of the data channel. This method and apparatus controls the amount of resources for the control channel when transmitting high-speed data, thereby increasing the efficiency of data channel resources.

Description

  The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting a data channel and a control channel at the same transmission time interval.

  In general, as an example of a radio communication system, a transmission method used in a single carrier frequency division multiple access (hereinafter referred to as “SC-FDMA”) system is a DFDMA (Distributed FDMA) method. Includes LFDMA (Localized FDMA) system.

  FIG. 1 is a block diagram showing a transmitter of a general LFDMA system. As illustrated in FIG. 1, a discrete Fourier transform (hereinafter referred to as “DFT”) precoder 101 and an inverse fast Fourier transform (hereinafter referred to as “IFFT”) unit 102. In addition to transmitters including the above, other transmitter types can also be realized. The implementation of the DFT precoder 101 and IFFT 102 as shown in FIG. 1 facilitates changing LFDMA system parameters without high hardware complexity.

  The difference between OFDM and SC-FDMA is discussed in terms of transmitter configuration. In addition to the IFFT unit 102 used for multi-carrier transmission in a normal OFDM transmitter, the LFDMA transmitter additionally includes a DFT precoder 101 connected to the input side of the IFFT unit 102. The M subcarriers output from the DFT precoder 101 are mapped to the input points NM to N-1 of the IFFT unit 102, and are thereby occupied and transmitted by a band composed of adjacent subcarriers. In general, the input / output size N of the IFFT unit 102 is larger than the input / output size M of the DFT precoder 101. An output signal of the IFFT 102 is transmitted through a parallel-to-serial (P / A) converter 104 and a cyclic prefix (CP) adder 106.

  In uplink transmission, control information transmitted through a control channel by a user equipment (User Equipment: UE) mainly includes ACK (Acknowledge) / NACK (Non-Acknowledge) necessary for transmission of downlink packet data. Or it is a channel quality indicator (Channel Quality Indicator: CQI).

  FIG. 2 shows transmission of control information in a general SC-FDMA system.

  Referring to FIG. 2A, in the SC-FDMA system, a separate frequency resource 201 different from the data channel is allocated to the control channel in order to transmit control information. When transmitting control information through the allocated frequency resource 201, the UE cannot transmit packet data. This is because, when packet data and control information are transmitted simultaneously in the same transmission section, the single carrier characteristics cannot be satisfied and PAPR (Peak to Average Power Ratio) increases.

  Accordingly, when the control information needs to be transmitted in the transmission section for packet data transmission by the UE, the control information is transmitted through the frequency resource 203 of the data channel as shown in FIG. Transmitted along with. In other words, the packet data, the control information, and the reference signal are time-multiplexed with the same frequency resource 203 and transmitted.

  FIG. 3 is a block diagram illustrating a transmitter that multiplexes and transmits packet data and control information before input to the DFT precoder in a general SC-FDMA system. As shown in the figure, data 301 including P symbols and control information 302 including S symbols are multiplexed into M symbols by a multiplexer 303 and then input to a DFT precoder 304 having size M. Is done. As described above, the output of DFT precoder 304 is mapped to the input of IFFT 305 having size N.

  As shown in FIG. 3, when packet data and control information are multiplexed before the DFT precoder, the scheduled M input symbols are allocated based on the information amounts of the data channel and the control channel, respectively. Need to be done. According to one of the general schemes, input symbols are assigned according to transmission formats set for the control channel and the data channel, as in the WCDMA (Wideband Code Division Multiple Access) scheme. In other words, when the number of symbols is set according to the transmission format fixed in the control channel, other input symbols excluding the control channel symbols are used for data transmission. This is because the data rate of the data channel usually varies according to the scheduling, and the transmission format of the control channel is fixedly set by higher layer signaling.

  However, when the transmission format of the control channel is fixed as described above, the number of symbols occupied by the control channel is reduced from the symbols that can be transmitted through the packet data channel, thereby reducing the data rate. To do. At this time, the data rate is reduced by an amount corresponding to “the number of symbols used for the control channel × MCS (Modulation and Coding Scheme) level”. Therefore, if the UE acquires a high MCS level scheduled for high-speed data transmission, the number of data bits that are not transmitted may increase due to transmission of control information.

  Accordingly, in order to solve the above-described problems of the prior art, an object of the present invention is to provide a method and apparatus for controlling the amount of resources used for a control channel according to a data rate of a UE in a wireless communication system. It is in.

  It is another object of the present invention to provide a method and apparatus for controlling the amount of control channel resources according to a transmission format used based on a data rate used by a UE or a scheduling data rate.

  Another object of the present invention is to provide a method and apparatus for transmitting control information using the same modulation scheme used for data transmission by the UE.

  It is another object of the present invention to provide a method and apparatus for calculating the number of modulation symbols required for transmission of a control channel according to a data channel transmission format.

  An object of the present invention is to provide a UE apparatus and method for multiplexing and transmitting a data channel and a control channel in an SC-FDMA system.

  Another object of the present invention is to provide a base station (Node B) apparatus and method for receiving multiplexed data channels and control channels in an SC-FDMA system.

  To achieve the above object, according to one aspect of the present invention, there is provided a method for transmitting data and control information in a wireless communication system, provided according to a transmission format used for a data channel. Determining a control channel format; generating data according to a transmission format of the data channel; generating control information according to the determined control channel format; multiplexing data and control information; And transmitting the multiplexed data and control information through the subcarrier resources allocated to.

  According to another aspect of the present invention, a user equipment (UE) device for transmitting data and control information in a wireless communication system, wherein the control determines a given control channel format according to a transmission format used for a data channel A data generator that generates data according to the transmission format of the data channel, a control information generator that generates control information according to the determined control channel format, and the data and control information are multiplexed and assigned to the data channel And a transmission unit for transmitting through the subcarrier resource.

  According to another aspect of the present invention, a method for receiving data and control information in a wireless communication system, wherein an uplink signal including data and control information is received through a subcarrier resource allocated to a data channel. Determining a given control channel format according to the transmission format used for the data channel; and demultiplexing the uplink signal according to the data channel transmission format and the control channel format to obtain data and control information. And a step of converting.

  Further, according to another aspect of the present invention, there is provided a base station (Node B) device for receiving data and control information in a wireless communication system, including data and control information through a subcarrier resource allocated to a data channel. A receiver for receiving a link signal; a controller for determining a given control channel format according to a transmission format used for the data channel; and a data channel transmission format and a control channel format for obtaining data and control information And a demultiplexer for demultiplexing the uplink signal according to the above.

  In a wireless communication system using a single carrier frequency division multiple access scheme, the control information and data for uplink transmission are multiplexed to satisfy a single carrier characteristic, thereby reducing PAPR. Has an effect.

It is a block block diagram which shows the transmitter of a general LFDMA system. It is a figure which shows transmission of the control information in a general SC-FDMA system. FIG. 2 is a block configuration diagram showing a transmitter that multiplexes and transmits control information and packet data before input to a DFT precoder in a general SC-FDMA system. 4 is a flowchart illustrating a procedure of transmitting data and control information by a UE according to the first embodiment of the present invention. 4 is a flowchart illustrating a procedure of simultaneously receiving data and control information by a Node B according to the first embodiment of the present invention. It is a block block diagram which shows the transmitter of UE by the 1st Embodiment of this invention. It is a block block diagram which shows the receiving apparatus of Node B by the 1st Embodiment of this invention. 7 is a flowchart illustrating a procedure for transmitting data and control information by a UE according to a second embodiment of the present invention. 7 is a flowchart illustrating a reception procedure of a base station for Node B according to a second embodiment of the present invention. It is a block block diagram which shows the transmitter of UE by the 3rd Embodiment of this invention. It is a block block diagram which shows the receiving apparatus of Node B by the 3rd Embodiment of this invention. 10 is a flowchart illustrating a procedure for transmitting data and control information by a UE according to a fourth embodiment of the present invention. 10 is a flowchart illustrating a procedure for simultaneously receiving data and control information by a Node B according to a fourth embodiment of the present invention. It is a block block diagram which shows the transmitter of UE by the 4th Embodiment of this invention. It is a block block diagram which shows the receiving apparatus of Node B by the 4th Embodiment of this invention.

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

  When it is determined that a specific description related to a known function or configuration related to the present invention makes the gist of the present invention unclear, a detailed description thereof will be omitted.

  The present invention relates to an amount of resources used by a control channel in order to efficiently use transmission resources when data and control information are transmitted simultaneously in one time interval in a wireless communication system. Change according to the data rate.

  Here, one time interval means a transmission time interval (hereinafter referred to as “TTI”).

  A general data rate means the amount of information data transmitted at unit time intervals. However, this data rate can mean the size of the amount of radio resources required by the UE for transmission of information data as an extended concept of the present invention. In other words, the data rate of the present invention should be understood as meaning the size or transmission power level of transmission bits transmitted by the UE in unit time intervals, ie transmission time units. The size of the transmission bit means the number of physical layer bits in the physical layer, the number of modulation symbols, or the size of the transmission block represented by the transmission format. The transmission power level means the power transmitted by the UE, and is a standard that is a power level required for actual data transmission after compensating for absolute transmission power, path loss difference between UEs, or channel difference. It may also mean an additional power level (that is, power offset) necessary for transmitting the corresponding data amount with respect to the power level. This has the same meaning as a signal-to-noise ratio (SNR) necessary for the base station (Node B) to receive the corresponding data amount normally.

  To this end, the present invention provides a method for selecting a control channel transmission format (TF) (hereinafter also referred to as “control channel format”) according to a data rate, and control information and data having a variable TF. A device for transmitting and receiving at the same time interval is basically provided. Furthermore, the present invention provides a method for defining other control channel formats according to the data rate, a method for calculating, and a method for transmitting data using the remaining resources except for selected control channel resources.

  An important feature of the present invention is that the control channel is transmitted alone in determining the control channel format such as the number of control channel symbols, the number of bits, or the modulation scheme required to transmit the control information. The format set by upper layer signaling or a predetermined format is used, and when the control channel is transmitted together with data, the control channel format is determined based on the data rate or transmission format of the data channel at each TTI. It is to be done. Here, each symbol means a modulated complex symbol and is mapped to one transmission unit such as one subcarrier or subband.

  In one embodiment of the present invention, a data channel transmission format or data rate includes a power level required for the data channel, a transmission format index indicating the amount of data that can be transmitted, and a data channel modulation and code rate (rate) will be described later corresponding to the case of using the MCS level indicating the method. However, it is understood in the art that any type of information in which the transmission rate or transmission format of the data channel can be identified can be used to determine the transmission format of the control channel without specific reference herein. It is self-evident to those skilled in the field. The following description of the present invention is based on the uplink of a wireless communication system using the SC-FDMA scheme, but it goes without saying that such a specific system configuration does not limit the scope of the present invention.

<First Embodiment>
UE sets in advance a plurality of control channel formats based on MCS levels indicating data modulation schemes and code rates, and selects control channel formats based on MCS levels of data channels transmitted in each TTI to set control channels To do. Here, the MCS level means a combination of a modulation scheme (for example, QPSK (Quadrature Phase Shift Keying) scheme, 16QAM (16-ary Quadrature Amplitude Modulation) scheme) and a code rate used for data transmission. The higher the datum rate, the higher the dating rate is obtained, i.e. when the control information is multiplexed with the data transmission, the coding of the control information is the modulation scheme and code rate used for the uplink data channel transmission. Given by.

  In the first embodiment of the present invention, for convenience of explanation, the format of the control channel is defined by the number of symbols for the control channel obtained after modulation. In other embodiments, the control channel transmission format may be defined by at least one of parameters such as MCS level, physical layer bit number, and code rate.

  When data is transmitted at a low MCS level, the allowable power level for each modulation symbol is also low. Therefore, a large number of modulation symbols are used for transmission of control information, thereby obtaining an energy level that satisfies the reception quality. If data is transmitted at a high MCS level, the UE has good channel conditions and can assign a high power level to each modulation symbol. Therefore, even if a small number of modulation symbols are used for transmission of control information, an energy level that satisfies the required reception quality can be obtained.

  Table 1 below shows various examples of setting the control channel format. Here, S_ori represents the number of symbols for the control information (original number of symbols) when only the control information is transmitted without data, and S represents the number of symbols for the control information when the control information is transmitted together with the data. Represents the number of symbols. In other embodiments, S_ori may have a signaled value or a value predetermined by the designer.

  In Example 2 of the number of symbols for the control channel, when the control information is transmitted alone (without data), the data and the control information use the same format when the data is transmitted at a low MCS level. When data is transmitted at a high MCS level, a format (S_add) additionally set for control information is used. Here, S_add has a value smaller than S_ori.

  In the example 3 of the number of symbols for the control channel, when data transmission power is used to transmit the control channel and the data channel at the same time, the number of symbols is required to satisfy the total energy. Therefore, when the data transmission power is set higher than the case where the data transmission power is transmitted only through the control channel, the number S of symbols of the control channel is smaller than the number of symbols S_ori of the original control channel. When the data transmission power is set to be lower than when only the control channel is transmitted, the number of the original control channel depends on the power ratio so that a number S larger than the number of symbols S_ori of the original control channel is used. It is determined by scaling the number of symbols S_ori. Here, PSD_control (Power Spectrum Density-control) represents a power level necessary for transmitting only the control channel, and PSD_n represents a power level necessary for transmission according to the nth data channel transmission format. The format information indicating the number of symbols of the control channel can be defined in advance by the standard or set by higher layer signaling.

  FIG. 4 is a flowchart illustrating a procedure for transmitting data and control information by a UE according to the first embodiment of the present invention.

  Referring to FIG. 4, when the transmitted control information and data are generated in the same TTI in step 401, the UE checks the MCS level for the data channel in step 402, and the control channel given by this MCS level. Select a format. Thereafter, in step 403, the UE generates control information including S symbols by controlling the code rate or the number of repetitions of the control information according to the number S of symbols in the control channel format. When the code rate is fixed, the UE performs rate matching on the input control information in a manner similar to data, and thereby S control symbols corresponding to the number S of symbols to be actually transmitted. The control information including is generated.

  Then, in step 404, the UE calculates the symbol number P of the data channel. Here, the number of symbols P of the data channel is obtained by subtracting the number of control channel symbols from the number of all symbols M due to the scheduled resource (P = MS). Next, in step 405, data including P symbols is generated. Specifically, the UE generates data including P symbols by performing rate matching and modulation according to the number of symbols P of the data channel corresponding to the amount of physical layer that can be transmitted. The generated data and control information are multiplexed and transmitted at step 406.

  Steps 404 and 405 for generating data and step 403 for generating control information can be executed not only in the order shown, but also in the reverse order or simultaneously.

  FIG. 5 is a flowchart illustrating a procedure for simultaneously receiving data and control information by the Node B according to the first embodiment of the present invention.

  Referring to FIG. 5, in step 501, the Node B receives a signal in which control information and data are multiplexed through a predetermined frequency resource. CQI is periodically transmitted by the UE, and ACK / NACK information is transmitted only when downlink data is received. Therefore, Node B accurately recognizes the time interval for receiving a signal including data and control information. In step 502, Node B selects a control channel format. Specifically, the Node B selects a control channel format corresponding to the MCS level determined through scheduling. The Node B notifies the UE of the MCS level of the data channel determined through the scheduling information, and the UE transmits data using the same MCS level as the MCS level scheduled by the Node B. Therefore, the control channel format used by Node B and UE is always the same.

  In step 503, the Node B obtains the number P of data channel symbols using the number of symbols in the selected control channel format. Thereafter, in step 504, the Node B demultiplexes the received signal using the number of symbols of the data channel and the control channel, thereby converting the received signal including M symbols into P data channel symbols and S pieces. Divided into control channel symbols. In steps 505 and 506, the Node B outputs pure data and control information after demodulating and decoding the symbols of each channel. At this time, the steps 505 and 506 can be executed not only in the order shown, but also in the reverse order or simultaneously.

  FIG. 6 is a block diagram illustrating a UE transmission apparatus according to the first embodiment of the present invention.

  Referring to FIG. 6, the data rate controller 601 receives the MCS information scheduled by the Node B from the Node B through a separate channel (for example, a scheduling channel) and transmits the MCS information to the control channel controller 604. When there is control information to be transmitted, the control channel controller 604 determines the number S of control information symbols corresponding to the MCS level of the data channel represented by the MCS information based on, for example, Table 1 described above. . The control information generator 603 receives the number S of control information symbols from the control channel controller 604, performs modulation, rate matching, encoding, and the like on the input information bits, and thereby performs S control including control information. Generate a symbol.

  When the control channel controller 604 transmits the number of symbols S of the control information to the data rate controller 601, the data rate controller 601 calculates the number of symbols P usable for data transmission based on the number of symbols S of the control information. To do. The data generator 602 generates data including P data symbols through modulation, rate matching, and encoding of input information bits based on the P symbols of data transmitted from the data rate controller 601.

  The generated data symbols and control symbols are multiplexed by a multiplexer 605, and a DFT precoder 606 generates a frequency domain signal including SC-FDMA symbols by performing DFT on M symbols output from the multiplexer 605. . Thereafter, the IFFT unit 607 maps the frequency domain signal to the assigned subcarrier, thereby converting the frequency domain signal into a time domain signal to be transmitted.

  FIG. 7 is a block diagram illustrating a Node B receiving apparatus according to the first embodiment of the present invention.

  Referring to FIG. 7, the Node B obtains a specific UE signal including M symbols by processing a signal received during one TTI through an FFT unit 707 and an IDFT unit 706. Then, the demultiplexer 705 classifies the UE signal into a data signal and control information. At this time, the scheduler 701 notifies the number of symbols occupied by each channel.

  That is, the scheduler 701 determines the MCS level of the data channel and transmits MCS information indicating the MCS level to the control channel controller 704. When there is control information to be transmitted, the control channel controller 704 determines the number of symbols S used for the control channel of the UE based on the MCS level represented by the MCS information, and the number of symbols of this control channel. S is transmitted to the scheduler 701. The scheduler 701 determines the number of symbols P obtained by subtracting the number of symbols S from the number of symbols M corresponding to all resources allocated to the UE as the number of symbols used for data transmission. Is transmitted to the data demodulator 702, and the symbol numbers P and S of the data channel and the control channel are notified to the demultiplexer 705.

  The data demodulator 702 receives the notification of the number P of data channel symbols from the scheduler 701, and demodulates and decodes the data channel symbols classified by the demultiplexer 705 in accordance with the modulation scheme and code rate of the corresponding MCS level. For this purpose, the scheduler 701 provides the data demodulator 702 with information about the number of symbols of the data channel and detailed operations. The control information demodulator 703 reports the control channel symbol number S from the control channel controller 704, and demodulates and decodes the control channel symbols classified by the demultiplexer 705 according to the corresponding modulation scheme and code rate, thereby Control information such as ACK / NACK or CQI is acquired.

<Second Embodiment>
In the second embodiment, the UE transmits after modulating the control channel by the same modulation scheme as the data channel for efficient use of resources. According to the prior art, since it is difficult to change the control channel format frequently according to the channel state of the UE, the UE uses a low format fixed for the control channel in order to maintain reliability. However, since the data channel is instantly scheduled based on the UE channel state information, the Node B variably sets the high speed data rate or the low data rate for the data channel according to the UE channel state. can do. When the Node B allocates a high data rate for the data channel, it can be determined that the UE is in good channel condition or has sufficient transmission power. Therefore, it is possible to transmit the control channel with high transmission power. Therefore, according to the second embodiment of the present invention, the control information is modulated by the same modulation scheme as the data, and the number of symbols for the control information is controlled according to this modulation.

  For the preferred implementation of the second embodiment, the modulation scheme for each data channel and the modulation scheme for each control channel are defined as shown in Table 2 below. Thereafter, the number of symbols required for the control channel is determined by the corresponding modulation scheme.

  FIG. 8 is a flowchart illustrating a procedure for transmitting data and control information by a terminal according to the second embodiment of the present invention.

  Referring to FIG. 8, if the control information and data transmitted in step 801 are generated in the same TTI, the UE checks the modulation scheme indicated by the MCS level of the data channel in step 802. Hereinafter, a case where two systems including a QPSK system and a 16QAM system are used as data channel modulation systems will be described. However, the present invention is of course applicable to other cases where other modulation schemes are used.

If the data channel modulation scheme is the QPSK scheme, the UE proceeds to step 803, modulates the control information by the QPSK scheme, and sets the number of symbols S corresponding to the QPSK scheme as the number S of symbols necessary for transmission of the control channel. Select _qpsk . On the other hand, if the data channel modulation scheme is the 16QAM scheme, the UE proceeds to step 804, modulates the control information by the 16QAM scheme, and corresponds to 16QAM as the number of symbols S required for transmission of the control channel. Select the number S _qam . The number of bits of control information before channel coding is already known, and generally twice as many bits as the number of bits of the QPSK method can be transmitted in the case of the 16QAM method. Therefore, when the 16QAM scheme is used, the number of symbols S _qam required for transmission of control information is reduced to half of the number of symbols S _{qpsk in} the case of the QPSK scheme.

  In step 805, the UE calculates the number of symbols P for the data channel to generate the data channel. The number P of data channel symbols corresponds to a value obtained by subtracting the number S of control channel symbols from the total number M of symbols according to scheduled resources (P = M−S). In step 806, the UE generates data including the number of P symbols through rate matching. In step 807, the UE multiplexes and transmits the generated data and control information. The steps 805 and 806 for generating data and the steps 803 and 804 for generating control information can be executed not only in the order shown, but also in the reverse order or simultaneously.

  FIG. 9 is a flowchart illustrating a procedure for simultaneously receiving data and control information by the Node B according to the second embodiment of the present invention.

Referring to FIG. 9, the Node B receives a signal in which control information and data are multiplexed through a predetermined frequency resource in step 901. In step 902, the Node B determines the number of symbols of the control channel based on the modulation format of the data channel scheduled for the UE. If the scheduled modulation format is QPSK, the Node B selects the QPSK symbol number S _qpsk as the symbol number S of the control channel in Step 903. On the other hand, if the scheduled modulation format is 16QAM, in step 904, the UE selects the number of symbols S _qam of 16QAM as the number of symbols S of the control channel.

  In step 905, the Node B calculates the number P of data channel symbols based on the number S of control channel symbols. In step 906, the Node B demultiplexes the received signal including M symbols based on the number of symbols in the data channel and the control channel, so that the P signal channel symbol and the S control channel symbol are demultiplexed. Break down. In step 907, the Node B demodulates and decodes the symbols of each channel and outputs pure data and control information.

  The second embodiment is realized by using the transmission / reception apparatus of the first embodiment as shown in FIGS.

<Third Embodiment>
In the third embodiment of the present invention, the number of symbols for transmitting control information is controlled by transmitting control information by the same modulation scheme as that of data. At this time, data and control information are multiplexed at the bit level before modulation instead of the symbol level after modulation. When multiplexing is performed before modulation, the UE or Node B does not need to separately select the modulation scheme of the control channel according to the modulation scheme of the data channel. Therefore, the transmission / reception procedure according to the third embodiment of the present invention is the same as the procedure of the second embodiment as shown in FIGS.

  FIG. 10 is a block diagram showing a terminal transmission apparatus according to the third embodiment of the present invention.

Referring to FIG. 10, when data and control information are transmitted simultaneously, the data resource for data transmission is variable, so the data rate controller 1001 transmits control information through the control channel controller 1004. The amount of resources to be notified is notified. Unlike the second embodiment, since data and control information are multiplexed before modulation, the amount of resources occupied by each channel is calculated by the number of bits. The data rate controller 1001 receives the number of bits S _b of the control information from the control channel controller 1004, and calculates the number of bits P _b that can be used for data transmission based on the total number of bits that can be transmitted. The data generator 1002 generates P _b data bits according to the number of bits P _b of the data channel calculated by encoding the pure data to be transmitted, and the generated data bits to the multiplexer 1005. provide.

Control information generator 1003 generates S _b pieces of control information bits in accordance with the number of bits S _b of the control information calculated by the pure control information by encoding the control channel controller 1004 to be transmitted, the generated The control information bits are provided to the multiplexer 1005. The multiplexer 1005 multiplexes the generated data symbol and control symbol. The multiplexed bits are modulated by the modulator 1006 using the same modulation method, processed by the DFT precoder 1007 and the IFFT unit 1008, and transmitted.

  FIG. 11 is a block diagram illustrating a Node B receiving apparatus according to the third embodiment of the present invention.

  Referring to FIG. 11, Node B obtains a signal of a specific UE including M symbols by processing a signal received during one TTI through an FFT unit 1108 and an IDFT unit 1107. These signals are demodulated by a demodulator 1106 using a demodulation method corresponding to the same modulation method, and input to the demultiplexer 1105 in the form of a bit stream.

The scheduler 1101 determines the MCS level of the data channel and transmits MCS information indicating the MCS level to the control channel controller 1104. When there is control information to be transmitted, the control channel controller 1104 determines the number of symbols S _b used for the control channel of the UE based on the MCS level indicated by the MCS information, and the number of control channel symbols S _b Is transmitted to the scheduler 1101. The scheduler 1101 determines the number of bits P _b obtained by subtracting the number of symbols S _b from the total number of bits that can be transmitted by the UE as the number of bits used for data transmission, and determines the number of bits P _b of the data channel. The data is transmitted to the data demodulator 1102 and the demultiplexer 1105.

The demultiplexer 1105 receives the number of bits P _b and S _b of each channel from the scheduler 1101 and the control channel controller 1104, classifies the bits of each channel from the bit stream, and the data demodulator 1102 controls the classified bits. It transmits to the information demodulator 1103. These demodulators 1102 and 1103 demodulate and decode the input bits under the control of the scheduler 1101 and the control information controller 1104, thereby obtaining pure data and control information.

<Fourth Embodiment>
The UE sets in advance a plurality of control channel formats according to a data transmission format (TF), selects a control channel format corresponding to the TF of data transmitted in each TTI, and sets a control channel. Here, the TF according to the fourth embodiment of the present invention means a transport block size (TBS) corresponding to the amount of data transmitted by the UE, and the MCS level and the total amount of frequency resources that can be used. Determined by. For convenience of explanation, the control channel format is defined by the number of symbols of the control channel in the present invention. Although not specifically described here, parameters such as the MCS level or the number of bits in the physical layer are defined as a control channel transmission format according to a modified embodiment of the present invention.

  If a low TF is used, the power level that can be allowed for the modulation symbols is also low. Therefore, a large number of modulation symbols are used for transmission of control information, thereby obtaining an energy level that satisfies the required reception quality. When data is transmitted at a high MCS level, the UE has good channel conditions and can assign a high power level to each modulation symbol. Therefore, even if a small number of modulation symbols are used for transmission of control information, an energy level that satisfies the required reception quality can be obtained.

  Table 3 below shows various examples of setting the control channel format.

  In Example 1, the number of control channel symbols is defined for each TF. In Example 2, the reference symbol number S_ref of the control channel is predefined, and the symbol number S required for the control channel is the power level PSD_k required for data transmission for each TF (where k is a TF index). And a comparison between the power level of the data when the reference symbol number is used. In Table 3, when the data power level is high, the power level available for the control channel is also high. Therefore, control information can be transmitted using a small number of symbols.

  FIG. 12 is a flowchart illustrating a procedure for transmitting data and control information by a UE according to the fourth embodiment of the present invention.

  Referring to FIG. 12, when the transmitted control information and data are generated in the same TTI in step 1201, the UE checks the TF index for the data channel in step 1202, and the control channel given by this TF index. Select a format. Thereafter, in step 1203, the UE generates control information including S symbols by controlling the code rate or the number of repetitions of the control information according to the number S of symbols in the control channel format. When the code rate is fixed, the UE performs rate matching on the input control information in a manner similar to data, and thereby includes S control symbols corresponding to the number S of symbols to be actually transmitted. Generate control information.

  In step 1204, the UE calculates the number P of data channel symbols. Here, the number P of data channel symbols is obtained by subtracting the number of control channel symbols from the number M of all symbols due to the scheduled resource (P = MS). In step 1205, data including P symbols is generated. Specifically, the UE generates data including P symbols by performing rate matching and modulation according to the number of symbols P of the data channel corresponding to the amount of physical layer that can be transmitted. The generated data and control information are multiplexed and transmitted at step 1206.

  FIG. 13 is a flowchart illustrating a procedure for simultaneously receiving data and control information by the Node B according to the fourth embodiment of the present invention.

  Referring to FIG. 13, in step 1301, the Node B receives a signal in which control information and data are multiplexed through predetermined frequency resources. CQI is periodically transmitted by the UE, and ACK / NACK information is transmitted only when downlink data is received. Therefore, Node B accurately recognizes the time interval for receiving a signal including data and control information. In step 1302, Node B selects a control channel format. Specifically, the Node B selects a control channel format corresponding to the TF index determined through scheduling. The Node B notifies the UE of the TF index of the data channel determined through the scheduling information, and the UE transmits data using the same TF index as the TF index scheduled by the Node B. Therefore, the control channel format used by Node B and UE is always the same.

  In step 1303, the Node B obtains the number P of data channel symbols using the number of symbols in the selected control channel format. Thereafter, in step 1304, the Node B demultiplexes the received signal using the number of symbols of the data channel and the control channel, thereby converting the received signal including M symbols into P data channel symbols and S pieces. Divided into control channel symbols. In steps 1305 and 1306, the Node B demodulates and decodes the symbols of each channel, and then outputs pure data and control information.

  FIG. 14 is a block diagram illustrating a UE transmission apparatus according to the fourth embodiment of the present invention.

  Referring to FIG. 14, the data rate controller 1401 receives TF information scheduled by the Node B from the Node B through a separate channel (for example, a scheduling channel) and transmits the TF information to the control channel controller 1404. When there is control information to be transmitted, the control channel controller 1404 determines the number S of control information symbols corresponding to the TF index of the data channel represented by the TF information based on, for example, the above-described Table 3. . The control information generator 1403 generates S control symbols including control information after receiving the number of control information symbols S from the control channel controller 1404.

  When the control channel controller 1404 transmits the number of symbols S of the control information to the data rate controller 1401, the data rate controller 1401 calculates the number of symbols P that can be used for data transmission based on the number of symbols S of the control information. . The data generator 1402 generates data including P symbols of data transmitted from the data rate controller 1401 through modulation, rate matching, and encoding of input information bits.

  The generated data symbols and control symbols are multiplexed by a multiplexer 1405, and a DFT precoder 1406 generates a frequency domain signal including an SC-FDMA symbol by performing DFT on M symbols output from the multiplexer 1405. . Thereafter, the IFFT unit 1407 maps the frequency domain signal to the assigned subcarrier, thereby converting the frequency domain signal into a transmitted time domain signal.

  FIG. 15: is a block block diagram which shows the receiving apparatus of Node B by the 4th Embodiment of this invention.

  Referring to FIG. 15, the Node B obtains a signal of a specific UE including M symbols by processing a signal received during one TTI through an FFT unit 1507 and an IDFT unit 1506. Then, the demultiplexer 1505 classifies the UE signal into a data signal and control information. At this time, the scheduler 1501 notifies the number of symbols occupied by each channel. The scheduler 1501 determines the MCS level of the data channel and transmits a TF index corresponding to the determined MCS level to the control channel controller 1504. When there is control information to be transmitted, the control channel controller 1504 determines the number S of symbols used for the control channel of the UE based on the TF index scheduled for the UE, and the number of symbols S of this control channel. Is transmitted to the scheduler 1501. The scheduler 1501 determines the number of symbols P obtained by subtracting the number of symbols S from the number of symbols M corresponding to all resources allocated to the UE as the number of symbols used for data transmission. Is transmitted to the data demodulator 1502, and the symbol numbers P and S of the data channel and the control channel are notified to the demultiplexer 1505.

  The data demodulator 1502 receives the notification of the number P of data channel symbols from the scheduler 1501, and demodulates and decodes the data channel symbols classified by the demultiplexer 1505 in accordance with the modulation scheme and code rate of the corresponding TF index. For this, the scheduler 1501 provides the data demodulator 1502 with information about the number of symbols of the data channel and the detailed operation. The control information demodulator 1503 notifies the control channel controller 1504 of the number S of control channel symbols, and demodulates and decodes the control channel symbols separated by the demultiplexer 1505 according to the corresponding modulation scheme and code rate. Control information such as ACK / NACK or CQI is acquired.

<Fifth Embodiment>
The fifth embodiment of the present invention is the fourth embodiment of the present invention except that the control channel format is determined based on the power level required for data transmission instead of being determined for each TF. It is the same. In the present embodiment, the necessary power level means an absolute transmission power of the UE or a power offset additionally set to the reference power level in consideration of each TF and service with respect to the reference power level. The reference transmission power means a power level controlled by the Node B in order to maintain a predetermined reception level. The power additionally set with respect to the reference power level has the same meaning as the SNR necessary for receiving the corresponding data by the Node B.

  Generally, in the case of data transmission of the same service, the power level required for data transmission increases as the TF index of the data channel increases (that is, the data rate increases). The power level required for data transmission means the symbol power per subcarrier in the frequency domain or the power level per modulation symbol in the time domain. For convenience of explanation, in the fifth embodiment, the control channel format is defined by the number of symbols for the control channel. Although not described here, parameters such as the MCS level or the number of bits in the physical layer may be defined as a control channel transmission format according to a modified embodiment of the present invention.

  Table 4 below shows various examples of setting the control channel format.

  In example 1, the number of symbols for the control channel is defined for each PSD indicating the power level of the data channel. If the power level of the control channel is higher or lower than the power level of the data channel, it is inefficient to use the transmission power by the UE. Therefore, when the data channel and the control channel are transmitted simultaneously, it is desirable to set the power level of the control channel to be the same as that of the data channel. At this time, in order to maintain the reliability of the control channel, as the power level of the data channel is lower, the number of control channel symbols can be increased to repeat control information symbols more. Further, when the power level of the data channel is high, the number of control information symbols to be transmitted is reduced, and puncturing loss generated in the data portion due to transmission of control information can be minimized. Table 4 shows a method for setting the control channel format in order to calculate the number of symbols necessary for stable reception of the control information when the power level of the control information is set to be the same as that of the data channel.

  In example 2, the reference symbol number S_ref of the control channel is predefined, and the number of symbols required for the control channel is the power level PSD_k required for data transmission for each PSD (where k is the PSD of the data channel). Index) and the power level of the data channel when the reference symbol number is used. As can be seen from Table 4, when the power level of the data channel is high, the power level available for the control channel is also high. Therefore, it is possible to transmit control information using a small number of symbols. If the power level of the data channel is low, more symbols can be transmitted. Therefore, the required reliability of the control channel can be maintained even with a low PSD.

  The procedure and apparatus of the UE and Node B according to the fifth embodiment of the present invention are the same as those of the fourth embodiment except that the PSD of the data channel becomes the reference for selecting the transmission format of the control channel instead of the TF information. It is the same.

  As mentioned above, in the detailed description of the present invention, specific embodiments have been described. However, various modifications can be made without departing from the scope of the appended claims. It is clear to the person. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined based on the description of the scope of claims and equivalents thereof.

401 Step in which control information and data to be transmitted are generated in the same TTI 402 Step of selecting a control channel format given by the MCS level of the data channel 403 Code rate of control information according to the number of symbols S in the control channel format or A step of generating control information including S symbols by controlling the number of repetitions 404 A step of calculating the number P of symbols in the data channel 405 A step of generating data including P symbols 406 The generated data and control information , The step of multiplexing and transmitting

Claims (24)

A method for transmitting data and control information in a wireless communication system, comprising:
Determining a given control channel format according to the transmission format used for the data channel;
Generating data according to the transmission format of the data channel;
Generating control information according to the determined control channel format;
Multiplexing the data and the control information;
Transmitting the multiplexed data and control information through a subcarrier resource allocated to the data channel;
A method characterized by comprising: The control channel format is:
The method of claim 1, wherein at least one of a coding scheme, a modulation and coding scheme (MCS) level, a physical layer bit number, a modulation scheme, and a symbol number for the control information is indicated. The transmission format is
Indicates at least one of a power spectral density (PSD) indicating a power level allocated for the data transmission, a transmission format index indicating the amount of data, and an MCS level used for transmission of the data channel. The method of claim 1, wherein: Determining the control channel format comprises:
The method of claim 1, further comprising: determining a coding scheme of the control information given by a modulation scheme and a data rate used for the data channel. The step of multiplexing the data and the control information, and the step of transmitting the multiplexed data and control information,
The method of claim 1, further comprising: multiplexing the data and the control information at a symbol level after encoding and modulating the data and the control information. The step of multiplexing the data and the control information, and the step of transmitting the multiplexed data and control information,
The method of claim 1, further comprising the step of multiplexing at a bit level before encoding and modulating the data and the control information. A user equipment (UE) device for transmitting data and control information in a wireless communication system,
A controller for determining a given control channel format according to the transmission format used for the data channel;
A data generator for generating data according to the transmission format of the data channel;
A control information generator for generating control information according to the determined control channel format;
A transmitter that multiplexes the data and the control information and transmits the data through a subcarrier resource assigned to the data channel;
UE apparatus characterized by including. The control channel format is:
The UE apparatus according to claim 7, wherein at least one of a coding scheme, a modulation and coding scheme (MCS) level, a physical layer bit number, a modulation scheme, and a symbol number for the control information is indicated. The transmission format is
Indicates at least one of a power spectral density (PSD) indicating a power level allocated for the data transmission, a transmission format index indicating the amount of data, and an MCS level used for transmission of the data channel. The UE device according to claim 7.   The UE apparatus according to claim 7, wherein the controller determines a coding scheme of the control information given by a modulation scheme and a code rate used for the data channel.   The UE apparatus according to claim 7, wherein the transmission unit multiplexes the data and the control information at a symbol level after encoding and modulating the data and the control information. The transmitter is
A multiplexer that multiplexes the data and the control information at a bit level prior to encoding and modulating;
A modulator for modulating the output of the multiplexer by a modulation method;
The UE apparatus according to claim 7, comprising: A method for receiving data and control information in a wireless communication system, comprising:
Receiving an uplink signal including data and control information through a subcarrier resource assigned to a data channel;
Determining a given control channel format according to a transmission format used for the data channel;
Demultiplexing the uplink signal according to a transmission format of the data channel and the control channel format to obtain the data and the control information;
A method characterized by comprising: The control channel format is:
The method of claim 13, wherein at least one of a coding scheme, a modulation and coding scheme (MCS) level, a physical layer bit number, a modulation scheme, and a symbol number for the control information is indicated. The transmission format is
Indicates at least one of a power spectral density (PSD) indicating a power level allocated for transmission of the data, a transmission format index indicating the amount of data, and an MCS level used for transmission of the data channel. The method according to claim 13. Determining the control channel format comprises:
The method of claim 13, further comprising determining an encoding scheme of the control information given by a modulation scheme and a code rate used for the data channel.   The method of claim 13, further comprising: obtaining the data and the control information by demodulation and decoding after demultiplexing the data and the control information.   The method of claim 13, further comprising demodulating and decoding the uplink signal prior to demultiplexing. A base station (Node B) device for receiving data and control information in a wireless communication system,
A receiver for receiving an uplink signal including data and control information through a subcarrier resource allocated to a data channel;
A controller for determining a given control channel format according to a transmission format used for the data channel;
A demultiplexer for demultiplexing the uplink signal according to a transmission format of the data channel and the control channel format to obtain the data and the control information;
A Node B device comprising: The control channel format is:
The Node B apparatus according to claim 19, wherein the Node B apparatus indicates at least one of a coding scheme, a modulation and coding scheme (MCS) level, a number of physical layer bits, a modulation scheme, and a number of symbols for the control information. . The transmission format is
Indicates at least one of a power spectral density (PSD) indicating a power level allocated for transmission of the data, a transmission format index indicating the amount of data, and an MCS level used for transmission of the data channel. The Node B apparatus according to claim 19.   The Node B apparatus according to claim 19, wherein the controller determines a coding scheme of the control information given by a modulation scheme and a code rate used for the data channel.   The Node B apparatus according to claim 19, further comprising a data demodulator and a control information demodulator configured to demodulate the data output from the demultiplexer and the control information.   The Node B apparatus according to claim 19, further comprising a demodulator configured to demodulate and transmit the uplink signal to the demultiplexer before demultiplexing.

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