Base station device, user device, and method used in mobile communication system

Description of equivalent WO 2008105267 A1

Base station apparatus used in mobile communication system, user apparatus and method

Moth€The present invention relates to a mobile communication system to which orthogonal frequency division multiplexing (OFDM) is applied in downlink, and more particularly to a base station apparatus and communication control method.

Moth€The W-CDMA or HSDPA successor communication system, ie Long Term Evolution (LTE), is being studied by W-CDMA standardization body 3GPP, and as radio access systems, OFDM for downlink and uplink for uplink SC-FDMA (Single-Carrier Frequency Division Multiple Access) has been considered (see, for example, Non-Patent Document 1).

Moth€OFDM is a scheme in which a frequency band is divided into a plurality of narrow frequency bands (subcarriers), and data is loaded on each frequency band for transmission, and while the subcarriers are partially overlapped on the frequency, they interfere with each other. High-speed transmission can be realized and frequency utilization efficiency can be improved by arranging them densely without doing so.

Moth€SC-FDMA is a transmission scheme that can reduce interference between terminals by dividing a frequency band and transmitting using a different frequency band among a plurality of terminals. SC-FDMA is characterized in that the variation of transmission power is reduced, so that low power consumption and wide coverage of the terminal can be realized.

Moth€In general, in mobile communication, there is a pilot signal for use in channel estimation and measurement of radio quality, and in the LTE, this pilot signal is called a downlink reference signal (DL RS).

Moth€The downlink reference signal in LTE is represented by a two-dimensional sequence, and is composed of a two-dimensional orthogonal sequence and a two-dimensional pseudo random sequence. The mapping (subcarrier number) of the reference signal to the physical resource is represented by the following equation (non-patent document 2):

<maths num="1"><img file="WO2008105267A1_D0001.tif" /></maths>Here, k indicates a subcarrier number, l indicates an OFDM symbol number, and i indicates a slot number. m takes the following integer value.

<maths num="2"><img file="WO2008105267A1_D0002.tif" /></maths>Moth€N_BW^DLIs the number of subcarriers in the entire system band, 300 for a system bandwidth of 5 MHz, 600 for a system bandwidth of 10 MHz, and 1200 for a system bandwidth of 20 MHz. Here, p represents an antenna port number, and p is 0 if only one antenna is used, but can be p = 0, 1, 2, 3 when four antennas can be used.

Moth€In the above equation, the value of ﾎｽ is determined as the following equation.

<maths num="3"><img file="WO2008105267A1_D0003.tif" /></maths>Where f_hop(j) is a series of cell-specific integers, and represents a hopping pattern that changes every subframe or slot of the downlink reference signal. That is, f per cell_hopBy changing (j), it becomes possible to map downlink reference signals to different subcarriers for each cell.

Moth€In addition, f_hop(j) may be a fixed value independent of time. When such a fixed value is set for each cell, the downlink reference signal is mapping shifted by a fixed value different for each cell.

Moth€FIG. 1 shows an example of mapping of reference signals. Set the antenna port number to 0 (p = 0) and f_hopMapping to the physical resource (left side) when (j) is always 0 and the antenna port number is 0 (p = 0), and f_hopThe mapping to the physical resource (right side) when (j) is always 2 is shown. As shown, in the former case, the downlink reference signal is mapped to the k = 6 x j (j: integer greater than or equal to 0) th subcarrier in the first OFDM symbol (l = 0). However, in the latter case, the downlink reference signal is mapped to the k = 6.times.j + 2 (j: integer greater than or equal to 0) sub-carrier in the first OFDM symbol (l = 0). Thus, the downlink reference signal in LTE is f_hopBy setting (j) appropriately, it is mapped to different subcarriers for each cell.

Moth€By the way, the ratio of the transmission power per subcarrier (transmission power density per unit frequency) of the downlink reference signal described above to the transmission power per transmission subcarrier (transmission power density per unit frequency) of a normal data signal is fixed. It is also considered that the user apparatus demodulates 16 QAM and 64 QAM using the fixed value information (see, for example, Non-Patent Document 3). The above normal data signal is a physical downlink shared channel (PDSCH) as a physical channel. In demodulation of 16 QAM and 64 QAM, it is necessary to perform amplitude estimation. The estimation accuracy can be expected to be improved by performing demodulation using knowledge that the power density difference between the reference signal and the data signal is a fixed value. In this case, since the transmission power per subcarrier of the downlink reference signal is always constant, the transmission power per subcarrier of the normal data signal is also always constant.

Moth€Since the downlink reference signal is not transmitted in all OFDM symbols, there are time periods in which it is transmitted and in which it is not transmitted. Therefore, if the total transmission power of the base station is made constant, the transmission power density of the data signal may change for each OFDM symbol. Then, there is a concern that the above-mentioned amplitude estimation accuracy is likely to deteriorate. A method has also been proposed in which the transmission power density of the normal data signal is made constant in both time zones, regardless of whether the OFDM symbol includes the reference signal or not. In one of the methods, it is prohibited that a normal data signal is mapped to a predetermined subcarrier in a time zone in which the downlink reference signal is transmitted. No data is mapped to that predetermined subcarrier. By reducing the mappable subcarriers of the data signal, it is possible to increase the transmission power density of the data signal by that amount, and regardless of whether the reference signal is transmitted or not, the transmission power density of the data signal It can be kept constant. This technique is described, for example, in Non-Patent Document 3.<nplcit num="1"><text>3GPP TR 25.814 (V7.0.0), "Physical Layer Aspects for Evolved UTRA," June 2006</text></nplcit><nplcit num="2"><text>3GPP TR 36.211 (V0.3.1), "Physical Channels and Modulation," November 2006</text></nplcit><nplcit num="3"><text>R1-070088, Power Boosting of Reference Signal in E-UTRA Downlink</text></nplcit>

<p num="0015">Moth€As mentioned above, the reference signal is mapped to a particular subcarrier of a particular OFDM symbol. Since the reference signal is the basis of channel estimation at the receiving side (typically, the user equipment), the mapping position greatly affects the channel estimation accuracy. Therefore, as described above, in accordance with the mapping position of the reference signal shifting in the frequency direction or hopping in the time axis direction, the positions of the subcarriers (prohibited subcarriers) for which the mapping of the data signal is prohibited are also appropriate. Should be set to However, such mapping methods do not seem to be well studied so far.</p><p num="0016">Moth€It is an object of the present invention to appropriately arrange prohibited subcarriers so that transmission power density of data signal becomes constant in time in the next-generation mobile communication system in which mapping position of reference signal changes in frequency direction and time direction. It is an object of the present invention to provide a base station for performing, a user equipment and methods used therein.</p>

<p num="0017">Moth€The base station apparatus used in the present invention is used in a mobile communication system using an OFDM scheme in downlink. A base station apparatus performs an inverse Fourier transform on a signal in which a first signal and a second signal are mapped to subcarriers at different transmission power densities, and generates a transmission signal, and transmits the transmission signal to a user apparatus. And transmission means. The transmission power density of the second signal is maintained constant among a plurality of OFDM symbols regardless of whether the first signal is included in an OFDM symbol including the second signal. A subcarrier (prohibited subcarrier) for which mapping of the second signal is inhibited is determined. The prohibited subcarriers are determined based on mapped subcarriers of the first signal.</p>

<p num="0018">Moth€According to the present invention, in the next-generation mobile communication system in which the mapping position of the reference signal changes in the frequency direction and the time direction, the transmission power density of the non-reference signal (typically, data signal) becomes constant in time. As such, placement of prohibited subcarriers can be properly performed.</p>

<figref num="1">It is a figure which shows the example of a mapping of a downlink reference signal.</figref><figref num="2">It is a block diagram which shows the structure of the mobile communication system concerning the Example of this invention.</figref><figref num="3">It is explanatory drawing which shows the structure of a sub-frame.</figref><figref num="4">FIG. 7 is a diagram showing an example of mapping of subcarriers to two OFDM symbols.</figref><figref num="5">It is a partial block diagram showing a base station device concerning one example of the present invention.</figref><figref num="6A">It is a block diagram which shows the baseband signal processing part of the base station apparatus which concerns on one Example of this invention.</figref><figref num="6B">It is a figure which shows the detail of the layer 1 process part of a baseband signal process part.</figref><figref num="7">It is a figure which shows the example of mapping of a subcarrier in case the transmission power density of a downlink reference signal is the same as the transmission power density of PDSCH.</figref><figref num="8">FIG. 16 is a diagram showing an example of subcarrier mapping when the transmission power density of the downlink reference signal is larger than the transmission power density of PDSCH. It is a figure which shows the example of mapping of the subcarrier to an OFDM symbol.</figref><figref num="9A">It is a figure which shows the correspondence of the number of puncturing subcarriers, and those subcarrier numbers.</figref><figref num="9B">It is a figure which shows the correspondence of the number of puncturing subcarriers, and those subcarrier numbers.</figref><figref num="9C">It is a figure which shows the example of a mapping of a downlink reference signal.</figref><figref num="10">It is a figure (when system bandwidth is 5 MHz) which shows the correspondence of the offset power between a reference signal and another signal, and the number of puncturing subcarriers.</figref><figref num="11">It is a figure (in the case of system bandwidth 10 MHz) which shows the correspondence of the offset power between a reference signal and another signal, and the number of puncturing subcarriers.</figref><figref num="12A">It is a figure (in the case of system bandwidth 20 MHz) which shows the correspondence of the offset power between a reference signal and another signal, and the number of puncturing subcarriers.</figref><figref num="12B">The figure which shows the correspondence example of the number of puncturing subcarriers, and the transmission power value (offset value) of a reference signal.</figref><figref num="13A">FIG. 5 is a partial block diagram illustrating a user equipment according to an embodiment of the present invention.</figref><figref num="13B">It is a figure which shows the detail of a baseband process part.</figref>

Explanation of sign

50 cells 100₁, 100₂, 100₃, 100_nMoth€User equipment 102 Transmission / reception antenna 104 Amplifier 106 Transmission / reception unit 108 Baseband signal processing unit 110 Call processing unit 112 Application unit 200 Base station apparatus 202 Transmission / reception antenna 204 Amplifier 206 Transmission / reception unit 208 Base band signal processing unit 210 Call processing unit 212 Transmission path Interface 2081 layer 1 processing unit 2082 MAC processing unit 2083 RLC processing unit 2084 subcarrier mapping determining unit 2085 DL transmission power control unit 300 access gateway device 400 core network

Moth€Next, the best mode for carrying out the present invention will be described based on the following embodiments with reference to the drawings. In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same functions, and the repeated explanation is omitted.

Moth€A mobile communication system to which a base station apparatus according to an embodiment of the present invention is applied will be described with reference to FIG.

Moth€The mobile communication system 1000 is a system to which, for example, Evolved UTRA and UTRAN (also called Long Term Evolution or Super 3G) is applied, and a base station apparatus (eNB: eNode B) 200 and a plurality of user apparatuses (UE: User) are used. Equipment) 100_n(100₁, 100₂, 100₃, ... 100_n, N is an integer of n&gt; 0). Base station apparatus 200 is connected to a higher station, for example, access gateway apparatus 300, and access gateway apparatus 300 is connected to core network 400. Here, the user device 100_nCommunicates with the base station apparatus 200 in the cell 50 by Evolved UTRA and UTRAN.

Moth€Each user device (100₁, 100₂, 100₃, ... 100_n) Has the same configuration, function, and state, and hence the user device 100 will be described below unless otherwise noted._nProceed with the explanation. For convenience of explanation, it is the user equipment that wirelessly communicates with the base station apparatus, but more generally includes both mobile terminals and fixed terminals.

Moth€Mobile communication system 1000 can operate with multiple variable bandwidths. As an example, such variable bandwidths are provided as 5 MHz, 10 MHz and 20 MHz. An operator operates one or more of the variable bandwidths as a system band, in which the user prepares one or more resource blocks (for example, 25 resource blocks in a 5 MHz system band) Can be used to communicate.

Moth€Hereinafter, the user device 100_n(100₁, 100₂, 100₃, ... 100_n) Has the same configuration, function, and state, and the user apparatus 100 will hereinafter be described unless otherwise noted._nProceed with the explanation.

Moth€The mobile communication system 1000 uses OFDM (Orthogonal Frequency Division Multiple Access) for downlink and SC-FDMA (Single Carrier-Frequency Division Multiple Access) for uplink as radio access schemes. As described above, OFDM is a scheme in which a frequency band is divided into a plurality of narrow frequency bands (subcarriers), and data is loaded on each frequency band for transmission. SC-FDMA is a transmission scheme that can reduce interference between terminals by dividing a frequency band and transmitting using a different frequency band among a plurality of terminals.

Moth€As described above, for downlink, each user apparatus 100_nThe physical downlink shared channel (PDSCH: Physical Downlink Shared Channel) shared and used and the downlink control channel for LTE are used. The downlink control channel for LTE is called a physical downlink control channel (PDCCH). The physical downlink control channel is also referred to as a downlink L1 / L2 control channel (D L L1 / L2 Control Channel).

Moth€For uplink, each user equipment 100_nThe physical uplink shared channel (PUSCH: Physical Uplink Shared Channel) and the uplink control channel for LTE are used. There are two types of uplink control channels: channels that are time-multiplexed with physical uplink shared channels and channels that are frequency-multiplexed. The latter is transmitted in a dedicated band separately from the physical uplink shared channel.

Moth€In uplink, downlink quality information (CQI: Channel Quality Indicator) and physical downlink shared channel (Downlink Shared Channel (DL-SCH) as transport channel) delivery confirmation information (CQI: Channel Quality Indicator) by the uplink control channel for LTE HARQ ACK information) is transmitted. Downlink quality information (CQI) is also used in resource allocation (scheduling) of a physical downlink shared channel, and in determining a transport format in adaptive modulation and coding (AMC).

Moth€As illustrated in FIG. 3, one subframe is, for example, 1 ms, and, for example, 14 OFDM symbols are included in one subframe. The physical downlink control channel is mapped to some OFDM symbols from the beginning of one subframe. The maximum number of OFDM symbols to which the physical downlink control channel is mapped is three. Physical downlink control channels are mapped in three ways: mapped to OFDM symbol # 1, mapped to OFDM symbols # 1 and # 2, mapped to OFDM symbols # 1 to # 2 and # 3 Be done. In FIG. 3, the physical downlink control channel is mapped to the first two OFDM symbols (# 1, # 2) of one subframe. Then, in the OFDM symbol to which the physical downlink control channel is not mapped, the data signal (physical downlink shared channel PDSCH, transport channel is DL-SCH) or synchronization channel (Synchronization Channel or Synchronization Signal, SCH) , Broadcast channel (BCH) and the like are transmitted. In addition, M resource blocks (RBs) are prepared in the frequency direction. As an example, the frequency band per resource block is 180 kHz, and 12 subcarriers exist in one resource block. For convenience of explanation, a resource occupying a band of one subcarrier and a period of one OFDM symbol is referred to as a "resource element". The number M of resource blocks is 25 when the system bandwidth is 5 MHz, 50 when the system bandwidth is 10 MHz, and 100 when the system bandwidth is 20 MHz.

Moth€FIG. 4 shows an example of subcarrier mapping for OFDM symbols # 4 and # 5 in the case of the subframe configuration of FIG. In FIG. 4, the total number of sub-carriers in one OFDM symbol is L, and the sub-carriers # 1, # 2,..., #L are numbered from the smaller frequency. When the system bandwidth is 5 MHz, L = 300, when the system bandwidth is 10 MHz, L = 600, and when the system bandwidth is 20 MHz, L = 1200. As shown in the figure, a downlink reference signal (DL RS) and a physical downlink shared channel (PDSCH) are mapped to subcarriers of OFDM symbol # 4. DL RS is transmitted at a rate of 1 to 6 subcarriers. In FIG. 4, DL RS is mapped to subcarriers whose subcarrier number is 6 ﾃm + 1 (where m: 0, 1, 2,...).

Moth€The following outlines the information items that may be included in the physical downlink control channel. The physical downlink control channel may include a physical downlink control channel format indicator, control information for downlink communication, that is, downlink scheduling information and / or control information for uplink communication. The physical downlink control channel format indicator indicates how many symbols the physical downlink control channel occupies in one subframe. The physical downlink control channel format indicator may be referred to as Physical Control Format Indicator Channel (PCFICH). Control information for downlink communication, that is, Downlink Scheduling Information may include downlink resource allocation information, downlink MIMO information, transmission format information, retransmission control information, and user identification information. The control information for the downlink communication may be referred to as Downlink Scheduling Grant or Downlink Assignment Information. The downlink resource allocation information represents which resource block is used to transmit the downlink data signal. Downlink MIMO information includes information on the number of streams, precoding vector, etc. when multi-input multi-output communication or multi-antenna communication is performed. The transmission format information specifies what combination of data modulation scheme and data size and channel coding scheme. Retransmission control information (HARQ: Hybrid Automatic Repeat reQuest) represents information when hybrid ARQ is performed. The retransmission control information may include a process number, a new data indicator, the number of retransmission sequences, and the like.

Moth€Control information for uplink communication includes uplink resource allocation information, transmission format information, reference signal information for demodulation, transmission power control information, user identification information, uplink acknowledgment information (ACK / NACK), overload indicator, A transmit power control command bit may be included. Uplink resource allocation information indicates which resource blocks can be used for uplink data transmission. The transmission format information specifies a combination of data modulation scheme and data size and channel coding scheme used for uplink communication. The information on the reference signal for demodulation indicates what kind of signal is used for the reference signal. The transmission power control information indicates how much the transmission power of the physical uplink shared channel should be different from the transmission power of the sounding reference signal. The uplink resource allocation information, the transmission format information, the information of the reference signal for demodulation, and the transmission power control information described above are collectively called Uplink Scheduling Grant. The acknowledgment information (ACK / NACK) on the uplink indicates whether the data transmitted from the user apparatus in the past on the uplink has been properly received by the base station. The acknowledgment information (ACK / NACK) on the uplink may be referred to as Physical Hybrid ARQ Indicator Channel (PHICH). The overload indicator is notified to the neighboring cells when the other-cell interference caused by the user apparatus in the other cell exceeds a predetermined value, and the notification is a signal for the user apparatus in the other cell to reduce the transmission power. is there. The transmission power control command bit indicates that the next transmission power of the sounding reference signal periodically transmitted from the user apparatus should be increased or decreased from the current value.

Moth€Note that the physical downlink control channel format indicator, transmission acknowledgment information (ACK / NACK) for uplink and transmission power control command bits are not included in the physical downlink control channel, but are not included in the physical downlink control channel and May be defined as different physical channels in a parallel relationship.

Moth€A base station apparatus 200 according to an embodiment of the present invention will be described with reference to FIG.

Moth€The base station apparatus 200 according to the present embodiment includes a transmission / reception antenna 202, an amplifier unit 204, a transmission / reception unit 206, a baseband signal processing unit 208, a call processing unit 210, and a transmission path interface 212.

Moth€From the base station apparatus 200 to the user apparatus 100 by downlink_nThe packet data to be transmitted to the base station apparatus 200 is input to the baseband signal processing unit 208 from the upper station located above the base station apparatus 200, for example, the access gateway apparatus 300 via the channel interface 212.

Moth€The baseband signal processing unit 208 performs transmission processing in the RLC layer such as packet data division processing, combining processing, transmission processing of RLC (Radio Link Control) retransmission control, MAC retransmission control processing, etc. Transfer to the transmission / reception unit 206. The processing in the baseband signal processing unit 208 includes, for example, transmission processing of HARQ, scheduling, transmission format selection, channel coding, inverse fast Fourier transform (IFFT) processing, and the like. As described later, the baseband signal processing unit 208 determines, for each subframe, the number of OFDM symbols to which the physical downlink control channel is mapped, and to the physical downlink control channel and the subcarriers of the physical downlink shared channel. Mapping, transmission power control for the physical downlink control channel, and physical downlink shared channel are performed.

Moth€In the transmitting and receiving unit 206, frequency conversion processing is performed to convert the baseband signal output from the baseband signal processing unit 208 into a radio frequency band, and then amplified by the amplifier unit 204 and transmitted from the transmitting and receiving antenna 202.

Moth€On the other hand, the user apparatus 100 by uplink_nFor data to be transmitted to base station apparatus 200 from the above, the radio frequency signal received by transmission / reception antenna 202 is amplified by amplification section 204, frequency converted by transmission / reception section 206 and converted to a baseband signal, and baseband signal processing It is input to the part 208.

Moth€In the baseband signal processing unit 208, FFT processing, IDFT processing, error correction decoding, reception processing of MAC retransmission control, reception processing of RLC layer, etc. are performed on the input baseband signal, and transmission line interface 212 is used. Is transferred to the access gateway device 300.

Moth€The call processing unit 210 performs call processing such as setting and releasing communication channels, status management of the radio base station 200, and resource allocation.

Moth€The configuration of the baseband signal processing unit 208 will be described with reference to FIG. 6A.

Moth€The baseband signal processing unit 208 includes a layer 1 processing unit 2081, a MAC (Medium Access Control) processing unit 2082, an RLC processing unit 2083, a subcarrier mapping determination unit 2084 and a DL transmission power control unit 2085.

Moth€The layer 1 processing unit 2081, the MAC processing unit 2082, the subcarrier mapping determining unit 2084, the DL transmission power control unit 2085, and the call processing unit 210 in the baseband signal processing unit 208 are mutually connected.

Moth€The layer 1 processing unit 2081 performs channel coding and IFFT processing of data transmitted in downlink and channel decoding, IDFT processing, FFT processing and the like of data transmitted in uplink. The layer processing unit 2081 maps information of the physical downlink control channel and the physical downlink shared channel to subcarriers based on the subcarrier information notified from the subcarrier mapping determination unit 2084. In the OFDM symbol in which the DL RS is transmitted, the DL RS is mapped to predetermined subcarriers.

Moth€A process of multiplexing the physical downlink control channel, the physical downlink shared channel, and the DL RS in the layer 1 processing unit 2081 and mapping to a subcarrier will be described in more detail using FIG. 6B.

Moth€The layer 1 processing unit 2081 includes a data signal processing unit 208102, a serial / parallel conversion unit (S / P) 20814, a multiplexing unit (MUX) 20816, a fast inverse Fourier transform unit (IFFT) 20818, and a cyclic prefix (CP). And a digital-to-analog converter (D / A) 208112, and a reference signal generator 208114. The data signal processing unit 20812 includes an encoder 208102A, a data modulator 208102B, and an interleaver 208102C. The reference signal generation unit 208114 includes a multiplication unit 208114A and a multiplication unit 208114B.

Moth€The data signal processing unit 208102 performs processing on a data signal to be transmitted in downlink. The encoder 208102A performs channel coding to increase the error resilience of the data signal. The coding may be performed in various manners known in the art, such as convolutional coding or turbo coding. In this embodiment, adaptive modulation and coding (AMC) control is performed on a data signal, and the channel coding rate is adaptively changed in accordance with an instruction from the MAC processing unit 2082. Data modulator 208102 B performs data modulation of the data signal in any suitable modulation scheme, such as QPSK, 16 QAM, 64 QAM, and so on. In this embodiment, AMC control is performed on the data signal, and the modulation scheme is adaptively changed in accordance with an instruction from the MAC processing unit 2082. Interleaver 208102 C rearranges the order of bits included in the data signal according to a predetermined pattern.

Moth€Although processing elements for the control channel are not explicitly shown in FIG. 6B, the same processing as the data signal processing unit 208102 is performed for the control channel. However, AMC control may not be performed for the control channel.

Moth€A serial-to-parallel converter (S / P) 208104 converts a serial signal sequence (stream) into a parallel signal sequence. The number of parallel signal sequences may be determined according to the number of subcarriers.

Moth€A multiplexing unit (MUX) 208106 multiplexes a data sequence representing an output signal from the serial / parallel conversion unit (S / P) 208104 and a reference signal. The multiplexing may be done in any of time multiplexing, frequency multiplexing or time and frequency multiplexing. A broadcast channel may be multiplexed in addition to the data sequence and the reference signal. Here, multiplexing section (MUX) 208106 receives the reference signal and physical downlink control channel and physical downlink shared channel mapping information of the relevant subframe from subcarrier mapping determining section 2084, and based on the above mapping information, The data series and the reference signal are multiplexed. That is, the multiplexing unit (MUX) 208106 maps the data sequence and the reference signal to subcarriers based on the mapping information. The mapping information of the reference signal, the physical downlink control channel, and the physical downlink shared channel also includes information on DTX subcarriers described later. That is, the multiplexer (MUX) 208106 does not map any signal in DTX subcarriers.

Moth€A fast inverse Fourier transform unit (IFFT) 208108 performs fast inverse Fourier transform on the signal input thereto to perform modulation of the OFDM scheme.

Moth€CP adding section 208110 creates a transmission symbol by adding Cyclic Prefix (CP) to the modulated symbol of the OFDM scheme. There are two types of CP length (CP length), Long CP and Short CP, and it is selected which CP length is used for each cell.

Moth€A digital-to-analog converter (D / A) 208112 converts a baseband digital signal into an analog signal.

Moth€The reference signal generation unit 208114 multiplies a reference signal (referred to as a reference signal for convenience) by a random code sequence which is a first sequence and an orthogonal code sequence which is a second sequence, and generates a reference signal. prepare. Also, based on the transmission power information notified from the DL transmission power control unit 2085, the layer 1 processing unit 2081 transmits the transmission power of a subcarrier to which the physical downlink control channel and the physical downlink shared channel are mapped (per unit band) Transmission power density or power density per subcarrier). Furthermore, the layer 1 processing unit 2081 sets the transmission power of the subcarrier to which the DL RS is mapped. Here, the transmission power of the subcarrier to which the DL RS is mapped may be set, for example, by being signaled from the upper node, or a value held as a parameter in the apparatus of the base station apparatus 200. It may be set by referring to.

Moth€The MAC processing unit 2082 performs MAC retransmission control of downlink data, for example, transmission processing of HARQ, scheduling, selection of transmission format, allocation of frequency resources, and the like. Here, scheduling refers to a process of selecting a user apparatus that transmits a data signal using a shared channel in the subframe, and for example, round robin or proportional fairness is used as an algorithm for the selection. It may be Further, the selection of the transmission format refers to determining the modulation scheme, coding rate, and data size of the data signal to be transmitted to the user apparatus selected in the scheduling. The determination of the modulation scheme, the coding rate, and the data size is performed, for example, based on the CQI reported in uplink from the user apparatus. Furthermore, the allocation of the frequency resource refers to a process of determining a resource block (RB) to be used for transmission of a data signal to be transmitted to a user apparatus selected in scheduling. The determination of the resource block is performed, for example, based on the CQI reported in uplink from the user apparatus.

Moth€Further, the MAC processing unit 2082 performs reception processing and scheduling of MAC retransmission control of uplink data, selection of a transmission format, allocation of frequency resources, and the like.

Moth€The RLC processing unit 2083 performs transmission processing of the RLC layer such as division / combination and transmission processing of RLC retransmission control for downlink packet data, and division / combination for uplink data and RLC such as reception processing of RLC retransmission control. The reception process of the layer is performed. The RLC processing unit 2083 may further perform processing of the PDCP layer in uplink and downlink.

Moth€The subcarrier mapping determination unit 2084 determines, for each subframe, subcarriers to which the physical downlink shared channel (PDSCH) is mapped. The determined subcarrier numbers to be mapped, such as PDSCH, are notified to the layer 1 processing unit 2081 as subcarrier information.

Moth€Subcarrier mapping determination section 2084 stores in memory a subcarrier number of a reference signal, the number of DTX subcarriers described later, and information indicating the correspondence between those subcarrier numbers (or, if necessary, separately). The information may be given from the processing element of A specific example of this correspondence will be described later with reference to FIG. 9A and the like. In the following description, OFDM symbol # 4 is presented as an example of an OFDM symbol to which the downlink reference signal and the physical downlink shared channel (PDSCH) are mapped, and OFDM symbol # 5 is used only for the physical downlink shared channel (PDSCH) Is presented as an example of an OFDM symbol to be mapped, but a similar description is given for other OFDM symbols to which a downlink reference signal and a physical downlink shared channel (PDSCH) are mapped, and a physical downlink shared channel (PDSCH) Only apply to the mapped OFDM symbols.

Moth€FIG. 7 shows an OFDM symbol (OFDM symbol # 4) to which the downlink reference signal and the physical downlink shared channel (PDSCH) are mapped, and an OFDM symbol (OFDM symbol # 5) to which only the physical downlink shared channel (PDSCH) is mapped. An example of subcarrier mapping of. Here, it is assumed that the transmission power per subcarrier of the downlink reference signal is the same as the transmission power per subcarrier of the physical downlink shared channel (PDSCH).

Moth€In this case, the physical downlink shared channel in OFDM symbol # 4 does not set part of the subcarrier to which DL RS is not mapped in OFDM symbol # 4 to a subcarrier to which some data is prohibited to be mapped. The transmission power per subcarrier of (PDSCH) and the transmission power per subcarrier of the physical downlink shared channel (PDSCH) in OFDM symbol # 5 are the same. That is, as illustrated, the subcarrier mapping determination unit 2084 may map the PDSCH to all subcarriers to which the downlink reference signal (DL RS) is not mapped in the OFDM symbol # 4.

Moth€FIG. 8 shows an OFDM symbol (OFDM symbol # 4) to which the downlink reference signal and the physical downlink shared channel (PDSCH) are mapped, and an OFDM symbol (OFDM symbol # 5) to which only the physical downlink shared channel (PDSCH) is mapped. An example of subcarrier mapping of. Here, it is assumed that the transmission power per subcarrier of the downlink reference signal is 3 dB larger (two times larger) than the transmission power per subcarrier of the physical downlink shared channel (PDSCH).

Moth€In this case, a physical downlink shared channel in OFDM symbol # 4 is set by setting a part of subcarriers to which DL RS is not mapped in OFDM symbol # 4 to be subcarriers to which some data is prohibited to be mapped. The transmission power per subcarrier of (PDSCH) and the transmission power per subcarrier of the physical downlink shared channel (PDSCH) in OFDM symbol # 5 are made the same. That is, as shown in the figure, subcarrier mapping determination section 2084 sets, in OFDM symbol # 4, a subcarrier to which neither the downlink reference signal (DLRS) nor the physical downlink shared channel (PDSCH) is mapped. For example, in the figure, 6 ﾃn + 2 subcarriers (n is an integer of 0 or more) are subcarriers to which neither a downlink reference signal (DLRS) nor a physical downlink shared channel (PDSCH) is mapped. This subcarrier may be called a "prohibited subcarrier" in the sense that any data is prohibited to be mapped, or may be called a "puncturing subcarrier" in the meaning of a subcarrier on which puncturing is performed. . Alternatively, it may be called "DTX subcarrier" in the sense that data transmission on that subcarrier is not performed. That is, no signal will be transmitted on DTX subcarriers. Then, in OFDM symbol # 4, the physical downlink shared channel is mapped to subcarriers that are not DTX subcarriers and to which no downlink reference signal is also mapped. In OFDM symbol # 5, physical downlink shared channel PDSCH is mapped to all subcarriers.

Moth€By setting DTX subcarriers, as a result, the number of subcarriers mapped to PDSCH in OFDM symbol # 4 in FIG. 8 corresponds to the number to which downlink PDSCH is mapped in OFDM symbol # 4 in FIG. Less than the number of carriers. Instead, if the total transmission power allocated per OFDM symbol in FIGS. 7 and 8 is the same, the physical downlink for any of the OFDM symbols (# 4 in FIG. 7 and # 4 and # 5 in FIG. 8). The transmission power density of the link sharing channel can be made to be substantially the same (although the reference signal is transmitted stronger than the other signals).

Moth€A more specific description will be given below. The maximum transmission power of the base station is 20 W, and the total number of subcarriers in one OFDM symbol is 300. At this time, assuming that the transmission power of each subcarrier is equal, the transmission power P per subcarrier_subcarrierIs P_subcarrierIt becomes = 20/300 = 0.066666 (W). Here, transmission power P per subcarrier of DL RS_DLRS, P_DLRSIn the case of 2 ﾃ0.066666 = 0.133333 (W), it is assumed that the number of DTX subcarriers is 50 in the OFDM symbol # 4, and 50 subcarriers for DL Silver€KnightS are prepared. In this case, the number of subcarriers on which the physical downlink shared channel (PDSCH) can be mapped in OFDM symbol # 4 is 300-50-50 = 200. The above calculation means subtracting the number of DL RS subcarriers and the number of DTX subcarriers from the number of all subcarriers. At this time, assuming that the transmission power of each subcarrier to which PDSCH is mapped in OFDM symbol # 4 is equal, the transmission power P per subcarrier in OFDM symbol # 4_subcarrier⁽¹⁾Is P_subcarrier⁽¹⁾= (20-0.133333 x 50) / 200 = 0.006666.

Moth€On the other hand, in OFDM symbol # 5 following OFDM symbol # 4, no reference signal is mapped, and PDSCH is mapped to all subcarriers. Therefore, assuming that the transmission power of each subcarrier to which PDSCH is mapped in OFDM symbol # 5 is equal, the transmission power per subcarrier in OFDM symbol # 5 P_subcarrier⁽²⁾Is P_subcarrier⁽²⁾= P_subcarrierIt becomes = 20/300 = 0.066666. That is, when PDSCH is mapped to two OFDM symbols, the transmission power (density) of PDSCH in the first OFDM symbol # 4 and the transmission power (density) of PDSCH in the subsequent OFDM symbol # 5 are made comparable. It is possible to That is, when the number of OFDM symbols mapped to PDSCH is 2 or more, the number of subcarriers mapped to PDSCH (by setting DTX subcarriers) in OFDM symbol # 4 to which DL RS is transmitted. Can reduce the transmission power density of the PDSCH in any OFDM symbol and contribute to the improvement of the amplitude estimation accuracy.

Moth€Next, how the reference signal and DTX subcarriers are mapped will be described in more detail. Generally, in an OFDM symbol to which a reference signal is mapped, the reference signal is mapped at a rate of one for each predetermined number of subcarriers (for example, every six subcarriers). Assuming that the mapped subcarrier number of the reference signal is X, X is X = 6m + n_shiftMoth€Moth€ It can be expressed as m is an integer of 0 or more. n_shiftIs an amount set for each cell, and takes any value of 0, 1,... More generally n_shiftIs as described in "Background Art" [ﾎｽ + f_hop(j)] expressed as mod 6 (j is the largest number of integers not exceeding i / 2). A physical downlink shared channel (PDSCH) is mapped to a subcarrier other than the mapped subcarrier of the reference signal. As described later, puncturing subcarriers may be included.

Moth€The transmission power per subcarrier (physical transmission power density per unit band) of the physical downlink shared channel (PDSCH) does not depend on whether or not the downlink reference signal is mapped in the OFDM symbol to which PDSCH is mapped. It is set to a predetermined value. This predetermined value is equal to the transmission power density when the base station transmits at the maximum transmission power (rated power) and distributes power equally to all subcarriers in the system band. Therefore, in the OFDM symbol in which the downlink reference signal is transmitted, the sub-carriers to which PDSCH may be mapped are reduced according to the transmission power density (offset value with respect to other signals) of the downlink reference signal. In other words, prohibited subcarriers (DRX subcarriers or puncturing subcarriers) for which mapping of PDSCH is prohibited are set.

Moth€In the example described above, the base station transmits the transmission power per subcarrier of the physical downlink shared channel (PDSCH) (transmission power density per unit band) at the maximum transmission power (rated power), and Although the transmission power density in the case where power is equally distributed to all subcarriers in the system band is used, the transmission power per subcarrier of the physical downlink shared channel (PDSCH) (transmission power density per unit band) is The value is not limited to the above value, and may be another fixed value other than the above.

Moth€FIG. 9A shows the correspondence between the number of puncturing subcarriers and their subcarrier numbers. In the figure, X indicates the mapped subcarrier number of the reference signal with the smaller subcarrier number among two reference signals in one resource block (X = 6 m + n_shift). Twelve subcarriers are included in one resource block, and subcarrier numbers (0, 1, 2,..., 11) are set in ascending order of frequency from the low frequency side. When a plurality of puncturing subcarriers are set for one resource block, mapping is performed so that they are equally distributed among resource blocks. For example, when X = 0 and the number of puncturing subcarriers is four, the subcarrier numbers are set to be every three subcarriers as 1, 4, 7, 10. Alternatively, when three or more puncturing subcarriers are set in the OFDM symbol of a certain resource block, at least three puncturing subcarriers are set at the same subcarrier interval.

Moth€The illustrated mapping example is merely an example. For example, when the number of puncturing subcarriers per resource block is small (for example, in the case of 1, 2, and 3), puncturing subcarriers may be set so as not to be adjacent to the reference signal. This is because for signals in the vicinity of the reference signal, relatively high channel estimation accuracy can be expected. For example, when the number of puncturing subcarriers is 2, puncturing subcarriers may be set in the (X + 3) mod 12 and (X + 10) mod 12 locations. More generally, it is preferable that signals other than the reference signal be mapped as much as possible on subcarriers between mapped subcarriers of the reference signal and puncturing subcarriers.

Moth€Alternatively, the positional relationship between the mapped subcarrier of the reference signal and the puncturing subcarrier or the distance between them (subcarrier interval) may be arranged to be constant. For example, as shown in FIG. 9A, by defining (X + a) mod 12 (a is an integer from 0 to 11), the mutual distance (subcarrier interval) becomes a value based on a. Therefore, by fixing the value of a, regardless of the value of X, the positional relationship between the subcarrier to which the reference signal is mapped and the puncturing subcarrier, or the distance between them (or The subcarrier interval) becomes constant. In this case, since the accuracy of channel estimation for demodulation of PDSCH becomes constant, more stable transmission characteristics can be obtained.

Moth€Alternatively, the subcarrier number of the puncturing subcarrier is a subcarrier sub-carrier to which a reference signal transmitted from a transmit antenna different from the transmit antenna is mapped assuming that base station apparatus 200 has a plurality of transmit antennas. The configuration may include a carrier number. For example, considering p = 0 and 1 described in the background art, the subcarrier number of the puncturing subcarrier in the case of p = 0 is the subcarrier of the subcarrier to which the reference signal in the case of p = 1 is mapped. The configuration may include a number. More specifically, the subcarrier number X1 of the reference signal in the case of p = 0 is X1 = 6m + n_shiftAssuming that p = 1, the subcarrier number X2 of the reference signal is X2 = 6m + 3 + n_shiftTherefore, the subcarrier number of the puncturing subcarrier in the case of p = 0 is 6m + 3 + n._shiftIs included. The correspondence between the number of puncturing subcarriers and their subcarrier numbers in this case is shown in FIG. 9B. In the example described above, the subcarrier number of the puncturing subcarrier in the case of p = 0 is configured to include the subcarrier number of the subcarrier to which the reference signal in the case of p = 1 is mapped, but instead p The subcarrier number of the puncturing subcarrier in the case of 1 may be configured to include the subcarrier number of the subcarrier to which the reference signal in the case of p = 0 is mapped.

Moth€When the number of transmitting antennas is actually two, as shown in FIG. 9C, the signal is transmitted from the second transmitting antenna regardless of the transmitting power of the reference signal in order to improve the reception SIR of the reference signal. In the subcarrier of the reference signal, nothing is transmitted from the first transmission antenna. Also, on the subcarrier of the reference signal transmitted from the first transmission antenna, nothing is transmitted from the second transmission antenna. Therefore, as shown in FIG. 9B, the subcarrier numbers to which reference signals transmitted from different transmit antennas are mapped have puncturing subcarrier numbers, so that physical resources can be specifically identified by puncturing. Can prevent the number of resource elements from being reduced.

Moth€Also, even when the number of transmitting antennas is actually one, as shown in FIG. 9B, transmission is performed by setting a puncturing subcarrier number assuming a reference signal transmitted from the second transmitting antenna. The processing is the same for the cases where the number of antennas is 1 and 2, and it is possible to reduce the complexity of the base station apparatus that performs transmission processing and the mobile station that performs reception processing.

Moth€The relationship between the first antenna and the second antenna described above is also applied to the relationship between the third antenna and the fourth antenna.

Moth€FIG. 10 shows how many puncturing subcarriers are set in which resource block RB for various offset values Silver€hen the system bandwidth is 5 MHz. The offset value indicates how many decibels the reference signal is transmitted relative to other signals. For example, when the reference signal is transmitted 3 dB stronger than the other signals, two of the 12 subcarriers of all resource blocks are set as puncturing subcarriers. If the reference signal is transmitted 1 dB stronger than the other signals, one puncturing subcarrier is set for each even-numbered resource block, and the puncturing subcarriers are set for the other resource blocks (odd-numbered resource blocks). Not set

Moth€FIGS. 11 and 12 respectively show how many puncturing subcarriers are set in which resource block RB for various offset values Silver€hen the system bandwidth is 10 MHz and 20 MHz. The view of the list is similar to that of FIG.

Moth€In FIG. 10-12, puncturing subcarriers are set so that the offset values Silver€ecome 0, 1, 2,..., 6 dB, so the number of puncturing subcarriers set in each resource block is the same. It was not always there. However, such a setting method is not essential to the present invention. The number of puncturing subcarriers set in all resource blocks may be set to the same number, and instead, the offset value may be a non-integer value. For example, FIG. 12B shows transmission power values Silver€offset values) of reference signals when the number of puncturing subcarriers set in each resource block is 1, 2, 3, 4, 5, 6.

Moth€It will be described in more detail. Consider a case where the system bandwidth is 5 MHz (the number of subcarriers: 300, the number of subcarriers of the reference signal: 50, the number of resource blocks: 25) and the number of puncturing subcarriers set in each resource block is one. At this time, since the number of puncturing subcarriers of each resource block (12 subcarriers per resource block) is 1, the number of PDSCH mapping subcarriers is 225. In this case, assuming that the absolute value of the transmission power of one subcarrier of PDSCH is 1, the total transmission power in the OFDM symbol in which the reference signal is transmitted is 50 ﾃ1 ﾃ10^{1.76 / 10}The total transmission power in an OFDM symbol with + 225 ﾃ1 = 299.998 and no reference signal transmitted is 300 ﾃ1 = 300 and the total transmission power in an OFDM symbol with no reference signal transmission and the OFDM symbol with no reference signal transmitted The total transmission power can be made approximately equal. In the example described above, the case where the number of puncturing subcarriers in each RB is 1 has been described, but the same applies to the case where the number of puncturing subcarriers in each RB is 2, 3, 4, 5 and 6 as well. The total transmission power in the OFDM symbol in which the reference signal is not transmitted may be substantially equal to the total transmission power in the OFDM symbol in which the reference signal is not transmitted. Also, in the case of a system bandwidth other than 5 MHz, for example, similarly at 10 MHz and 20 MHz, the total transmission power in the OFDM symbol in which the reference signal is not transmitted and the total transmission power in the OFDM symbol in which the reference signal is not transmitted are substantially equal. Can.

Moth€In this case, since the number of subcarriers punctured in each resource block is constant, it is possible to reduce the complexity of the base station apparatus performing transmission processing and the mobile station performing reception processing.

Moth€The DL transmission power control unit 2085 determines the transmission power of the physical downlink control channel and the physical downlink shared channel, and notifies the layer 1 processing unit 2081 of the transmission power. The transmission power per subcarrier of the physical downlink shared channel (transmission power density per unit band) is predetermined regardless of whether or not the downlink reference signal is mapped in the OFDM symbol to which PDSCH is mapped. Set to a value. This predetermined value is equal to the transmission power density when the base station transmits at the maximum transmission power (rated power) and distributes power equally to all subcarriers in the system band. Alternatively, if the transmission power per subcarrier of the physical downlink shared channel (transmission power density per unit band) is constant regardless of whether or not the downlink reference signal is mapped, the base station can transmit at maximum transmission power. It may be a value other than the transmission power density when transmitting at (rated power) and distributing power equally to all subcarriers in the system band.

Moth€User equipment 100 according to an embodiment of the present invention with reference to FIG. 13A._nExplain.

Moth€13, the user device 100_nThe transmission / reception antenna 102 includes an amplifier unit 104, a transmission / reception unit 106, a baseband signal processing unit 108, a call processing unit 110, and an application unit 112.

Moth€For downlink data, a radio frequency signal received by the transmission / reception antenna 102 is amplified by the amplifier unit 104, frequency-converted by the transmission / reception unit 106, and converted into a baseband signal. The baseband signal is transferred to the application unit 112 after being subjected to FFT processing, error correction decoding, reception processing of retransmission control, and the like in the baseband signal processing unit 108.

Moth€On the other hand, uplink packet data is input from the application unit 112 to the baseband signal processing unit 108. The baseband signal processing unit 108 performs retransmission control (HARQ) transmission processing, transmission format selection, channel coding, DFT processing, IFFT processing, etc., and transfers the result to the transmission / reception unit 106.

Moth€The transmitting and receiving unit 106 is subjected to frequency conversion processing for converting the baseband signal output from the baseband signal processing unit 108 into a radio frequency band, and then amplified by the amplifier unit 104 and transmitted from the transmitting and receiving antenna 102.

Moth€Also, the baseband signal processing unit 108 demodulates and decodes the physical downlink control channel to obtain information such as the physical downlink control channel and the physical downlink shared channel. Here, information on which subcarrier the information on the physical downlink shared channel is mapped to (including information for specifying where the prohibited subcarrier is located) is the user apparatus 100._nIt has been acquired in advance. A process of acquiring information of the physical downlink shared channel is performed based on the information as to which subcarrier the physical downlink shared channel is mapped to.

Moth€A process of performing demodulation and decoding of the physical downlink control channel and acquiring information such as the physical downlink control channel and the physical downlink shared channel in the baseband signal processing unit 108 will be described in more detail using FIG. 13B. Do.

Moth€The baseband signal processing unit 108 performs multiplication by an analog-to-digital converter (A / D) 10802, a CP removal unit 10804, a fast Fourier transform unit (FFT) 10806, a separation unit (DeMUX) 10808, a multiplication unit 10810, and A section 10812, a channel estimation section 10814, a demodulation section 10816, and a subcarrier mapping information management section 10818 are provided.

Moth€An analog-to-digital converter (A / D) 10802 converts the received baseband analog signal into a digital signal.

Moth€CP removal section 10804 removes the CP from the received symbol, leaving an effective symbol portion.

Moth€A fast Fourier transform unit (FFT) 10806 performs fast Fourier transform on the input signal to perform demodulation in the OFDM scheme.

Moth€A separation unit (DeMUX) 10808 separates the reference signal and the data signal (user data or control data) from the received signal. Here, the demultiplexing unit (DeMUX) 108 receives from the subcarrier mapping information management unit 118 the mapping information of the reference signal and the physical downlink control channel and the physical downlink shared channel, that is, the reference signal in the corresponding subframe. Receives information on which subcarrier is mapped to the carrier and to which subcarrier the physical downlink control channel (control data) and the physical downlink shared channel (user data) are mapped, and based on the above information, received signals Separate the reference signal and the data signal (user data or control data).

Moth€Multiplication sections 10810 and 10812 multiply the reference signal by the random code sequence which is the first sequence and the orthogonal code sequence which is the second sequence.

Moth€The channel estimation unit 10814 performs channel estimation based on the reference signal and determines what channel compensation should be made to the received data signal.

Moth€Demodulation section 10816 compensates the data signal based on the channel estimation result, and restores the data signal transmitted from base station apparatus 200, that is, user data or control data.

Moth€The subcarrier mapping information management section 10818 is used to map the reference signal and the mapping information of the physical downlink control channel and the physical downlink shared channel, that is, to which subcarrier the reference signal is mapped in the subframe, and physical downlink It holds information as to which subcarrier the link control channel (control data) and the physical downlink shared channel (user data) are mapped to, and notifies the demultiplexing unit (DeMUX) 10808 of the mapping information. The mapping information may be system fixed information, or may be information notified from the base station apparatus 200 by broadcast information or individual signaling, for example, RRC Message.

Moth€The mapping information of the reference signal and the physical downlink control channel and the physical downlink shared channel held in the subcarrier mapping information management section 10818 also includes the information on the DTX subcarrier described above. That is, demultiplexing unit (DeMUX) 10808 performs processing to demultiplex the reference signal and the data signal (user data or control data) on the assumption that no signal is mapped in the DTX subcarrier.

Moth€The information on which subcarrier the information on the physical downlink shared channel is mapped to (including information for specifying where the prohibited subcarrier is located) is, for example, shown in FIG. 9A in the description of the base station apparatus 200. This corresponds to the subcarrier number of the puncturing subcarrier described with reference to FIGS. 9B, 9C, 10, 11, 12A, and 12B. In other words, the user device 100_n9A, FIG. 9B, FIG. 9C, FIG. 10, FIG. 11, FIG. 12A, and FIG. 12B in the description of the base station apparatus 200, taking into account the puncturing subcarriers described in FIG. Demodulate and decode. In other words, the user device 100_n9A, 9B, 9C, 10, 11, 12A and 12B in the description of the base station apparatus 200, the physical downlink shared channel is not transmitted in the puncturing subcarrier. Demodulation and decoding of the physical downlink shared channel in consideration of the above. Here, demodulation and decoding mean, for example, FFT processing in the above-described baseband signal processing unit 108, error correction decoding, reception processing of retransmission control, and the like.

Moth€That is, as described above, even when the number of transmitting antennas is actually one in the base station apparatus, puncturing is performed assuming the reference signal transmitted from the second transmitting antenna as shown in FIG. 9B. When the subcarrier number is set, the baseband signal processing unit 108 also transmits the reference signal transmitted from the second transmission antenna as shown in FIG. 9B even when the number of transmission antennas is actually one. Assuming that the reference signal to be transmitted from the second transmit antenna is mapped, it is considered that the subcarrier is a puncturing subcarrier to demodulate and decode the physical downlink shared channel.

Moth€The call processing unit 110 manages communication with the base station 200 and the like, and the application unit 112 performs processing and the like related to layers higher than the physical layer and the MAC layer.

Moth€In the above example, in the OFDM symbol in which the physical downlink shared channel (PDSCH) is transmitted, a puncturing subcarrier is set, and the subcarrier of the puncturing subcarrier is set to the subcarrier of the downlink reference signal. Although determined based on the position, puncturing subcarriers are set in the OFDM symbol in which the physical downlink control channel (PDCCH) is transmitted, and the subcarriers of the puncturing subcarriers are used as downlink reference signals. It may be determined based on the subcarrier position of. Alternatively, in an OFDM symbol in which PCFICH or PHICH is transmitted, puncturing subcarriers may be set, and subcarriers of the puncturing subcarriers may be determined based on subcarrier positions of downlink reference signals.

Moth€As shown in FIG. 9A and FIG. 9B, the base station apparatus, user apparatus and method according to the above-described embodiment are configured such that the subcarrier numbers of puncturing subcarriers are one pair with the subcarrier numbers to which the downlink reference signal is mapped. 1, and the sequence f in the background art_hopIt can be applied to any sequence of (j). That is, the base station apparatus, the user apparatus, and the method according to the above-described embodiment can be applied even when fixed shifting is applied even when hopping is applied to the downlink reference signal. .

Moth€In the embodiment described above, an example in a system to which Evolved UTRA and UTRAN (also called Long Term Evolution or Super 3G) is applied has been described. It is possible to apply to all systems using OFDM scheme on the link.

Moth€Thus, according to one embodiment of the present invention, a non-reference signal (typically, a data signal) can be prepared by preparing in advance the correspondence between the number of reference signals and prohibited subcarriers, locations, offset values, etc. It is possible to flexibly cope with the hopping of the reference signal, the change of the offset value, and the like while keeping the transmission power density of V) constant in time.

Moth€Although the invention has been described with reference to particular embodiments, the embodiments are merely illustrative, and those skilled in the art will understand various modifications, alterations, alternatives, substitutions, etc. I will. Although specific numerical examples are used to facilitate understanding of the invention, unless otherwise noted, those numerical values Silver€antre merely examples and any appropriate values Silver€ay be used. The division of each embodiment is not essential to the present invention, and two or more embodiments may be used as needed. Although the apparatus according to the embodiment of the present invention is described using a functional block diagram for convenience of explanation, such an apparatus may be realized in hardware, software or a combination thereof. The present invention is not limited to the above-described embodiments, and various modifications, alterations, alternatives, and replacements are included in the present invention without departing from the spirit of the present invention.

Moth€This international application claims priority based on Japanese Patent Application No. 2007-50837, filed Feb. 28, 2007, the entire content of which is incorporated into this international application.

Moth€This international application claims priority based on Japanese Patent Application No. 2007-71589 filed on March 19, 2007, the entire content of which is incorporated into this international application.