JP5781139B2 - Radio base station apparatus, mobile terminal apparatus, radio communication system, and radio communication method - Google Patents

Description

  The present invention relates to a radio base station apparatus, a mobile terminal apparatus, a radio communication system, and a radio communication method.

In the LTE (Long Term Evolution) system defined by ^{3GPP (3 rd Generation Partnership Project)} , the reference signal is arranged to:: (RB Resource Block) ( Reference Signal RS) resource blocks. For example, the downlink signal can be synchronously detected by receiving the reference signal in the mobile terminal device (Non-patent Document 1). The reference signal is scrambled (randomized by a known signal sequence) by a cell-specific scrambling signal.

  In 3GPP, an LTE-A (LTE-Advanced) system for realizing high-speed transmission with a wider coverage than the LTE system is being studied. In this LTE-A system, two types of reference signals (a demodulation reference signal (DM-RS) and a channel quality measurement reference signal (CSI-RS)) are defined in the downlink.

  The demodulation reference signal is used for demodulation of a physical downlink shared channel (Physical Downlink Shard Channel: PDSCH). This demodulation reference signal is subjected to precoding similar to PDSCH and transmitted to the mobile terminal apparatus. The channel quality measurement reference signal is used to measure channel quality information (Channel State Indicator) that the mobile terminal apparatus feeds back to the radio base station apparatus.

3GPP, TS 36.211

  The LTE-A system requires interference estimation with higher accuracy than the LTE system. Therefore, in the LTE-A system, it is necessary to design the configuration of the downlink channel quality measurement reference signal so as to satisfy such a requirement.

  The present invention has been made in view of the above points, and a radio base station apparatus, a mobile terminal apparatus, a radio communication system, and radio communication that transmit and receive downlink channel quality measurement reference signals in consideration of highly accurate interference estimation It aims to provide a method.

The radio base station apparatus of the present invention is configured to generate a channel quality measurement reference signal corresponding to a plurality of antenna port numbers, map the channel quality measurement reference signal to two adjacent symbols in time, and It includes a mapping unit that maps the antenna port the channel reference signal quality measurement mapped to 2 symbols the adjacent rather based on number of subcarriers, a reference signal for channel quality measurement to be mapped to consecutive subcarriers The antenna port numbers are not consecutive.

  According to the present invention, it is possible to transmit and receive a downlink channel quality measurement reference signal in consideration of highly accurate interference estimation.

(A), (b) is a figure for demonstrating the mapping of CSI-RS which concerns on this invention. (A), (b) is a figure for demonstrating the mapping of CSI-RS which concerns on this invention. (A)-(c) is a figure for demonstrating the mapping of CSI-RS which concerns on this invention. It is a figure which shows the radio | wireless communications system which has a radio base station apparatus and mobile terminal apparatus which concern on embodiment of this invention. It is a block diagram which shows schematic structure of the radio base station apparatus which concerns on embodiment of this invention. It is a block diagram which shows schematic structure of the mobile terminal device which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
In the mobile terminal apparatus, a reception propagation channel for a serving cell is estimated using a channel quality measurement reference signal (CSI-RS). Moreover, in a mobile terminal device, the interference from a periphery cell is estimated using CSI-RS.

  When estimating interference using CSI-RS, interference power is calculated | required from the residual of two CSI-RS. When two CSI-RSs used for estimating interference power are mapped apart in the frequency domain / time domain, the channel state at each mapping position is different, and therefore the residual of the two CSI-RSs When the interference power is estimated from the above, the interference cannot be estimated with high accuracy.

  In consideration of such highly accurate interference estimation, the present inventors have examined the arrangement of reference signals for downlink channel quality measurement and have completed the present invention.

  That is, the essence of the present invention is to generate a CSI-RS and map this CSI-RS to two adjacent symbols, or generate a CSI-RS and map this CSI-RS to a specific symbol, Puncturing a predetermined subcarrier in this specific symbol.

In the present invention, the following two modes can be cited as CSI-RS mapping for highly accurate interference estimation.
(1) In the first mode, CSI-RS is mapped to two adjacent symbols. In this case, as shown in FIG. 1 (a), CSI-RS may be mapped to two adjacent symbols in time, and as shown in FIG. 1 (b), two adjacent symbols at the CSI-RS frequency. It may be mapped to. As the fading variation between two adjacent symbols is smaller, the better interference estimation can be performed. Therefore, the mapping using two symbols adjacent in the time domain as in the former is suitable for application to a low-speed moving environment.

  FIGS. 1A and 1B illustrate a case where CSI-RS is mapped as a pair to two symbols adjacent in frequency or two symbols adjacent in time, but the present invention is not limited to this. Alternatively, the CSI-RS may be mapped as a pair to two symbols that are adjacent in frequency or time, or to two symbols that are adjacent in time. In this case, the symbols that are close in frequency or time are two symbols that have the same channel state to a sufficient extent to estimate the interference power with high accuracy.

  Thus, by mapping CSI-RS as a pair to two symbols that are adjacent in frequency or two symbols that are adjacent in time, the channel state at each CSI-RS mapping position becomes substantially equal. When interference power is estimated from the residual of two CSI-RSs, interference can be estimated with high accuracy.

(2) In a 2nd aspect, CSI-RS is mapped to a specific symbol and the predetermined subcarrier in this specific symbol is punctured. That is, a predetermined subcarrier in an OFDM symbol multiplexed with CSI-RS is punctured. In this case, as shown in FIG. 2 (a), subcarriers separated from the CSI-RS may be punctured, and as shown in FIG. 2 (b), subcarriers adjacent to (adjacent to) the CSI-RS. May be punctured.

  In this way, by mapping the CSI-RS to a specific symbol and puncturing a predetermined subcarrier in the specific symbol, a portion of the predetermined subcarrier can be used as a reference regardless of the channel state. When interference power is estimated from the residual of two CSI-RSs, interference can be estimated with high accuracy.

  3A to 3C show an example in which CSI-RS is mapped in the first mode. The reference signal arrangement patterns shown in FIGS. 3A to 3C are FDM (Frequency Division Multiplex) or TDM (Time Division Multiplex) arrangement patterns. The arrangement pattern shown in FIG. 3 (a) is an arrangement pattern of 24 subcarrier periods, the arrangement pattern shown in FIG. 3 (b) is an arrangement pattern of 16 subcarrier periods, and the arrangement pattern shown in FIG. 3 (c). The pattern is an arrangement pattern of 12 subcarrier periods.

  3 (a) to 3 (c), the black part is the Release 8 LTE reference signal part, the upward-sloping diagonal line part is the Release 10 LTE DM-RS part, and the upward-sloping diagonal part is the present invention. It is the CSI-RS part that defines As can be seen from FIGS. 3A to 3C, the CSI-RS is mapped to two adjacent symbols in time (CSI-RS pair), and CSI- for eight transmission antennas (port 0-7). RS pairs are mapped to subcarriers. Here, the CSI-RSs of ports 0, 2, 4, and 6 are mapped to four consecutive subcarriers, and the CSI-RSs of ports 1, 3, 5, and 7 are mapped to four consecutive subcarriers.

  Thus, by mapping the CSI-RS to two adjacent symbols, or mapping the CSI-RS to a specific symbol and puncturing a predetermined subcarrier in the specific symbol, two CSI-RSs are mapped. The interference can be estimated with high accuracy when the interference power is estimated from the residual.

  FIG. 4 is a diagram showing a radio communication system having radio base station apparatuses and mobile terminal apparatuses according to the embodiment of the present invention.

The wireless communication system is a system to which, for example, E-UTRA (Evolved UTRA and UTRAN) is applied. The radio communication system includes a radio base station apparatus (eNB: eNodeB) 2 (2 ₁ , 2 ₂ ... 2 _l , l is an integer of l> 0) and a plurality of mobile terminal apparatuses communicating with the radio base station apparatus 2 (UE) 1 _n (1 ₁ , 1 ₂ , 1 ₃ ,... 1 _n , n is an integer of n> 0). The radio base station device 2 is connected to an upper station, for example, an access gateway device 3, and the access gateway device 3 is connected to the core network 4. The mobile terminal 1 _n communicates with the radio base station apparatus 2 by E-UTRA in the cell 5 (5 ₁ , 5 ₂ ). Although the present embodiment shows two cells, the present invention can be similarly applied to three or more cells. Since each mobile terminal device (1 ₁ , 1 ₂ , 1 ₃ ,... 1 _n ) has the same configuration, function, and state, the following description will be given as the mobile terminal device 1 _n unless otherwise specified. To proceed.

  In a radio communication system, OFDM (Orthogonal Frequency Division Multiple Access) is applied to the downlink and SC-FDMA (Single Carrier Frequency Division Multiple Access) is applied to the uplink as radio access schemes. OFDM is a multi-carrier transmission scheme that performs communication by dividing a frequency band into a plurality of narrow frequency bands (subcarriers) and mapping data to each subcarrier. SC-FDMA is a single carrier transmission scheme in which frequency bands are divided for each terminal, and a plurality of mobile terminal apparatuses use different frequency bands to reduce interference between mobile terminal apparatuses.

Here, a communication channel in E-UTRA will be described.
For downlink, a physical downlink shared channel (PDSCH) shared by each mobile terminal device 1 _n and a physical downlink control channel (PDCCH) are used. The physical downlink control channel is also called a downlink L1 / L2 control channel. User data, that is, a normal data signal is transmitted through the physical downlink shared channel. Further, downlink scheduling information (DL Scheduling Information), acknowledgment information (ACK / NACK), uplink scheduling grant (UL Scheduling Grant), TPC command (Transmission Power Control Command), and the like are transmitted by the physical downlink control channel. The downlink scheduling information includes, for example, the ID of a user who performs communication using a physical downlink shared channel, and information on the transport format of the user data, that is, data size, modulation scheme, retransmission control (HARQ: Hybrid ARQ). And downlink resource block allocation information.

  The uplink scheduling grant includes, for example, the ID of a user who performs communication using the physical uplink shared channel, information on the transport format of the user data, that is, information on the data size and modulation scheme, This includes resource block allocation information, information related to uplink shared channel transmission power, and the like. Here, the uplink resource block corresponds to a frequency resource and is also called a resource unit.

  Also, the delivery confirmation information (ACK / NACK) is delivery confirmation information related to the uplink shared channel. The contents of the acknowledgment information are expressed by either an acknowledgment (ACK: Acknowledgement) indicating that the transmission signal has been properly received or a negative acknowledgment (NACK: Negative Acknowledgement) indicating that the transmission signal has not been properly received. Is done.

For the uplink, a physical uplink shared channel (PUSCH) shared by each mobile terminal device 1 _n and a physical uplink control channel (PUCCH) are used. . User data, that is, a normal data signal is transmitted through the physical uplink shared channel. The physical uplink control channel transmits downlink quality information and physical downlink shared channel delivery confirmation information to be used for downlink shared physical channel scheduling processing, adaptive modulation / demodulation, and encoding processing.

  In the physical uplink control channel, in addition to CQI and delivery confirmation information, a scheduling request for requesting resource allocation of an uplink shared channel (Scheduling Request), a release request (Release Request) in persistent scheduling (Persistent Scheduling), etc. May be sent. Here, the resource allocation of the uplink shared channel means that the radio base station can perform communication using the uplink shared channel in the subsequent subframe using the physical downlink control channel of a certain subframe. This means that the device notifies the mobile terminal device.

The mobile terminal apparatus 1 _n communicates with the optimal radio base station apparatus. In the example of FIG. 4, the mobile terminal device 1 _1, 1 ₂ communicates with the radio base station apparatus 2 _1, the mobile terminal device 1 ₃ is communicating with the radio base station apparatus 2 _2.

  FIG. 5 is a diagram showing the configuration of the radio base station apparatus according to the embodiment of the present invention. Although only the transmission unit is illustrated in FIG. 5, this radio base station apparatus naturally includes a reception unit that receives and processes an uplink signal.

  The radio base station apparatus shown in FIG. 5 includes a shared channel signal generation unit 21 that generates a shared channel signal, a puncture processing unit 22 that performs a puncture process on the shared channel signal, and a CSI-RS sequence generation unit that generates a CSI-RS sequence. 23, a time / frequency mapping unit 24 that maps CSI-RS to the time domain / frequency domain, a channel multiplexing unit 25 that multiplexes a shared channel signal and a signal including CSI-RS, and IFFT ( An IFFT unit 26 that performs Inverse Fast Fourier Transform, a CP addition unit 27 that adds a CP (Cyclic Prefix) to the signal after IFFT, and a transmission antenna 28 are mainly configured. Note that the radio base station apparatus can perform MIMO transmission using a plurality of transmission antennas, but FIG. 5 shows the configuration of one transmission antenna in order to simplify the description.

  The shared channel signal generation unit 21 generates a shared channel signal (signal transmitted by PDSCH) using downlink transmission data. The shared channel signal generation unit 21 generates a shared channel signal based on the CSI measurement value measured by the radio base station apparatus using the CSI-RS included in the uplink signal. The shared channel signal generation unit 21 outputs the generated shared channel signal to the puncture processing unit 22.

  The puncture processing unit 22 performs puncture processing on the generated shared channel signal. In the puncturing process, as shown in FIGS. 2A and 2B, predetermined subcarriers in an OFDM symbol in which CSI-RS is multiplexed are punctured. The predetermined subcarrier to be punctured is based on predetermined pattern information. The puncture processing unit 22 outputs the shared channel signal after the puncture processing to the channel multiplexing unit 25.

  The CSI-RS sequence generation unit 23 generates a CSI-RS to be multiplexed on the RB. The CSI-RS sequence generation unit 23 outputs the CSI-RS to the time / frequency mapping unit 24.

  The time / frequency mapping unit 24 maps the CSI-RS to the time domain / frequency domain in the RB. The time / frequency mapping unit 24 maps the CSI-RS to two adjacent symbols, or maps the CSI-RS to a specific symbol. That is, in the first mode, the time / frequency mapping unit 24 maps the CSI-RS to two adjacent symbols in time as shown in FIG. 1 (a), or as shown in FIG. 1 (b). Are mapped to two adjacent symbols at the CSI-RS frequency. In the second mode, the time / frequency mapping unit 24 maps the CSI-RS to a specific symbol as shown in FIGS. 2 (a) and 2 (b). The RB that maps the CSI-RS is based on predetermined pattern information. The time / frequency mapping unit 24 outputs the mapped signal to the channel multiplexing unit 25.

  The channel multiplexing unit 25 channel-multiplexes the common channel signal and the signal including CSI-RS. The channel multiplexing unit 25 outputs the channel multiplexed signal to the IFFT unit 26. The IFFT unit 26 performs IFFT on the channel multiplexed signal and converts it into a time domain signal. IFFT unit 26 outputs the signal after IFFT to CP adding unit 27. CP adding section 27 adds a CP to the signal after IFFT. The CP-added signal is transmitted from the transmission antenna 28 to each mobile terminal device on the downlink (downlink physical shared channel).

  FIG. 6 is a diagram showing the configuration of the mobile terminal apparatus according to the embodiment of the present invention. The mobile terminal apparatus shown in FIG. 6 includes a reception antenna 11, a CP removal unit 12 that removes a CP from a received signal, an FFT unit 13 that performs FFT (Fast Fourier Transform) on the CP-removed signal, a shared channel signal, and a CSI. A channel dividing unit 14 that divides a signal including RS, a depuncture processing unit 15 that depunctures a shared channel signal, a shared channel signal demodulation / decoding unit 16 that demodulates and decodes the depunctured shared channel signal, and a time Mainly from a time / frequency demapping unit 17 for demapping a CSI-RS mapped in a region / frequency region, and a noise / interference power estimation unit 18 for estimating interference power using the demapped CSI-RS. It is configured.

  A signal transmitted from the radio base station apparatus on the downlink (downlink physical shared channel) is received via the reception antenna 11 of the mobile terminal apparatus. CP removing section 12 removes the CP from the received signal. CP removing section 12 outputs the signal after CP removal to FFT section 13. The FFT unit 13 performs FFT on the signal after CP removal and converts it to a frequency domain signal. The FFT unit 13 outputs the signal after the FFT to the channel dividing unit 14. The channel division unit 14 performs channel division on the common channel signal and the signal including CSI-RS. The channel division unit 14 outputs the channel-divided signal to the depuncture processing unit 15.

  The depuncture processing unit 15 performs depuncture processing on the shared channel signal that is divided into channels. The depuncture processing unit 15 performs depuncture processing on the shared channel signal based on the pattern information. The shared channel signal after the depuncture process is output to the shared channel signal demodulation / decoding unit 16. Note that the pattern information (control information) may be notified from the radio base station apparatus to the mobile terminal apparatus via a broadcast channel (BCH), may be transmitted as an L1 / L2 control signal, and is notified by an upper layer. Also good.

  The shared channel signal demodulation / decoding unit 16 demodulates and decodes the depunctured shared channel signal to obtain received data.

  The time / frequency demapping unit 17 demaps the CSI-RS from the time domain / frequency domain in the RB. The RB for demapping CSI-RS is based on predetermined pattern information. The time / frequency demapping unit 17 outputs the demapped signal to the noise / interference power estimation unit 18. Note that the pattern information (control information) may be notified from the radio base station apparatus to the mobile terminal apparatus via a broadcast channel (BCH), may be transmitted as an L1 / L2 control signal, and is notified by an upper layer. Also good.

The noise / interference power estimation unit 18 estimates noise / interference power using the demapped CSI-RS, and outputs a noise / interference power value. In the case of the first mode, the noise / interference power estimation unit 18 estimates the noise / interference power based on the residual (difference) between two CSI-RSs adjacent in frequency or time. For example, when noise / interference power is estimated from the residual of two CSI-RSs adjacent in time, the square of the residual of the two adjacent CSI-RSs is as follows.
| Y _{TX # i-RX # j} (f, t) -y _{TX # i-RX # j} (f, t + 1) | ²
Here, y _{TX # i-RX # j} represents a reception signal transmitted from the transmission antenna Tx # i of the radio base station apparatus and received by the reception antenna Rx # j of the mobile terminal apparatus.

ここで、Ｇ_{ＣＳＩ−ＲＳ}＝｛（ｆ_ｘ，ｔ_ｙ），…｝はＣＳＩ−ＲＳの配置場所を表し、Ｎ_{ＣＳＩ−ＲＳ}はＣＳＩ−ＲＳの個数を表し、ＳはＲＳシンボルを表す。 Since the received noise of each CSI-RS is uncorrelated, the average noise / interference power is 2 (P _N + P _I ). Therefore, the noise / interference power at the reception antenna Rx # j of the mobile terminal apparatus can be estimated by averaging the received signal with all transmission / reception antennas in the band residual. That is, the noise / interference power at the receiving antenna Rx # j can be estimated by the following formula 1.

Here, G _CSI-RS = {(f _x , t _y ),...} Represents the location of _CSI-RS , N _CSI-RS represents the number of CSI-RS, and S represents an RS symbol.

When noise / interference power is estimated from the residuals of two CSI-RSs adjacent in frequency, the squares of the residuals of the two CSI-RSs are set as follows, and the square of the residuals in Equation 1 is By replacing the term with the following term, the noise / interference power can be estimated.
| Y _{TX # i-RX # j} (f, t) -y _{TX # i-RX # j} (f + 1, t) | ²
In the second mode, noise / interference power can be estimated by setting the punctured RS symbol to “0”.

A radio communication method in the radio base station apparatus and mobile terminal apparatus having the above configuration will be described.
In the radio communication method of the present invention, a CQI-RS is generated in a radio base station apparatus, this CQI-RS is mapped to two adjacent symbols, and a CQI mapped to two adjacent symbols in a mobile terminal apparatus. -Interference power estimation is performed using RS (first mode).

  Specifically, in the radio base station apparatus, the time / frequency mapping unit 24 maps the CSI-RS to two adjacent symbols in time or frequency, as shown in FIGS. Next, the channel multiplexing unit 25 channel-multiplexes the shared channel signal and the CSI-RS, and transmits this multiplexed signal to the mobile terminal apparatus on the downlink. At this time, pattern information (control information) is also transmitted to the mobile terminal apparatus in the downlink as necessary.

  In the mobile terminal apparatus, the channel dividing unit 14 divides the shared channel signal and the CSI-RS, and the shared channel signal demodulation / decoding unit 16 demodulates and decodes the shared channel signal. On the other hand, the CSI-RS is demapped and extracted by the time / frequency demapping unit 17. Then, the noise / interference power estimation unit 18 estimates the noise / interference power using the CSI-RS to obtain the noise / interference power value.

  Thus, in the wireless communication method of the present invention, by mapping CSI-RS as a pair to two adjacent symbols in time or frequency, the channel states at the respective CSI-RS mapping positions are substantially equal. When interference power is estimated from the residual of two CSI-RSs, interference can be estimated with high accuracy.

  In the radio communication method of the present invention, the CQI-RS is generated in the radio base station apparatus, the CQI-RS is mapped to a specific symbol, a predetermined subcarrier in the specific symbol is punctured, In the mobile terminal apparatus, interference power estimation is performed using a CQI-RS of a specific symbol and a punctured subcarrier (second mode).

  Specifically, in the radio base station apparatus, the CQI-RS is mapped to a specific symbol as shown in FIGS. Further, the shared channel signal is punctured by the puncture processing unit 22 as shown in FIGS. 2 (a) and 2 (b). Next, the channel multiplexing unit 25 channel-multiplexes the shared channel signal and the CSI-RS, and transmits this multiplexed signal to the mobile terminal apparatus on the downlink. At this time, pattern information (control information) is also transmitted to the mobile terminal apparatus in the downlink as necessary.

  In the mobile terminal apparatus, the channel division unit 14 divides the shared channel signal and the CSI-RS, and the shared channel signal is depunctured by the depuncture processing unit 15 and demodulated / demodulated by the shared channel signal demodulation / decoding unit 16. Decrypt. On the other hand, the CSI-RS is demapped and extracted by the time / frequency demapping unit 17. Then, the noise / interference power estimation unit 18 estimates the noise / interference power using the CSI-RS to obtain the noise / interference power value.

  As described above, in the radio communication method of the present invention, the CSI-RS is mapped to a specific symbol, and a predetermined subcarrier in the specific symbol is punctured to thereby determine a portion of the predetermined subcarrier regardless of the channel state. The interference can be estimated with high accuracy when the interference power is estimated from the residual of the two CSI-RSs.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications. In the said embodiment, a mapping pattern and the number of transmission / reception antennas are examples, and are not limited to this. In addition, the number of processing units and the processing procedure in the above description can be changed as appropriate without departing from the scope of the present invention. Each element shown in the figure represents a function, and each functional block may be realized by hardware or software. Other modifications can be made without departing from the scope of the present invention.

  The present invention is useful for an LTE-A system radio base station apparatus, mobile terminal apparatus, radio communication system, and radio communication method.

DESCRIPTION OF SYMBOLS 1 _n Mobile terminal apparatus 2 _n Radio base station apparatus 3 Access gateway 4 Core network 5 _N cell 11 Reception antenna 12 CP removal part 13 FFT part 14 Channel division part 15 Depuncture process part 16 Shared channel signal demodulation and decoding part 17 Time and frequency Demapping unit 18 Noise / interference power estimation unit 21 Shared channel signal generation unit 22 Puncture processing unit 23 CSI-RS sequence generation unit 24 Time / frequency mapping unit 25 Channel multiplexing unit 26 IFFT unit 27 CP addition unit 28 Transmitting antenna

Claims (10)

A generation unit for generating a channel quality measurement reference signal corresponding to a plurality of antenna port numbers;
Mapping while mapping the 2 symbols adjacent said channel reference signal for quality measurement in time, mapping the channel reference signal quality measurement mapped to 2 symbols based rather the adjacent to the antenna port number to subcarriers And comprising
A radio base station apparatus characterized in that antenna port numbers of channel quality measurement reference signals mapped to consecutive subcarriers are not consecutive.   The radio base station apparatus according to claim 1, wherein the mapping section maps channel quality measurement reference signals having consecutive antenna port numbers to non-contiguous subcarriers.   The radio base station apparatus according to claim 1 or 2, wherein information for mapping the channel quality measurement reference signal is transmitted to a mobile terminal apparatus. Together they are mapped to two adjacent symbols in the time, including a reference signal for channel quality measurement, which is mapping the channel reference signal quality measurement mapped to 2 symbols based rather the adjacent antenna port number to subcarriers A reception unit that receives a downlink signal, and an interference power estimation unit that performs interference power estimation using the channel quality measurement reference signal, the channel quality measurement reference signal mapped to consecutive subcarriers A mobile terminal device characterized in that antenna port numbers are not consecutive. Generator, and with maps in two symbols adjacent to the reference signal for the channel quality measurement time, based rather the adjacent to the antenna port number for generating a plurality of antenna ports numbers reference signals for channel quality measurement corresponding to A radio base station apparatus comprising a mapping unit that maps the channel quality measurement reference signal mapped to the two symbols to a subcarrier;
A mobile terminal apparatus comprising: a reception unit that receives a downlink signal including the channel quality measurement reference signal; and an interference power estimation unit that performs interference power estimation using the channel quality measurement reference signal;
And the antenna port number of the channel quality measurement reference signal mapped to consecutive subcarriers is not continuous. 6. The wireless communication system according to claim 5, wherein the mapping section maps the channel quality measurement reference signals of consecutive antenna port numbers to non-contiguous subcarriers .   The radio communication system according to claim 5 or 6, wherein the radio base station apparatus transmits information for mapping the channel quality measurement reference signal to the mobile terminal apparatus. In the radio base station apparatus, a channel quality measurement reference signal corresponding to a plurality of antenna port numbers is generated, the channel quality measurement reference signal is mapped to two adjacent symbols in time, and the antenna port number is a step of mapping the channel reference signal quality measurement mapped to 2 symbols the adjacent rather groups Dzu subcarriers, the mobile terminal device, comprising: receiving a downlink signal including the channel reference signal for quality measurement And a step of estimating interference power using the channel quality measurement reference signal, wherein the antenna port number of the channel quality measurement reference signal mapped to consecutive subcarriers is not continuous. Communication method.   9. The radio communication method according to claim 8, wherein the radio base station apparatus maps channel quality measurement reference signals having consecutive antenna port numbers to non-contiguous subcarriers.   The radio communication method according to claim 8 or 9, wherein the radio base station apparatus transmits information for mapping the channel quality measurement reference signal to the mobile terminal apparatus.

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