WO2010122910A1

WO2010122910A1 - Wireless communication system, base station apparatus and mobile station apparatus

Info

Publication number: WO2010122910A1
Application number: PCT/JP2010/056441
Authority: WO
Inventors: 陽介秋元; 昇平山田; 智造野上
Original assignee: シャープ株式会社
Priority date: 2009-04-22
Filing date: 2010-04-09
Publication date: 2010-10-28

Abstract

When two or more types of information of required qualities, which are different in allocated communication resources, are to be transmitted, communications can be performed which efficiently and simply satisfy the required qualities. A base station apparatus (200), which uses a MIMO (Multiple Input Multiple Output) system to transmit/receive, to/from mobile station apparatuses, a plurality of types of signals having different required qualities, comprises: an uplink spatial multiplexing information control unit (222) that selects, in accordance with the required qualities of signals, respective different numbers of spatial multiplexing sequences; an uplink modulation scheme/coding rate control unit (223) that selects, in accordance with the required qualities of the signals, at least either respective different modulation schemes or coding rates; and a transmission unit (210) that transmits, to the mobile station apparatuses, information indicating the selected numbers of spatial multiplexing sequences as well as information indicating the selected modulation schemes or coding rates.

Description

Wireless communication system, base station apparatus, and mobile station apparatus

The present invention relates to a radio communication system, a base station apparatus, and a mobile station apparatus that transmit and receive a plurality of types of signals having different required qualities using a MIMO (Multiple Input Multiple Multiple Output) scheme between the base station apparatus and the mobile station apparatus. About.

Traditionally, 3GPP (3rd Generation Partnership Project), an international standardization project, uses W-CDMA (Wideband-Code Division Multiple Access) and GSM (Global System Mobile for Mobile Communications) as a next generation cellular mobile communication system. The network specifications that have been developed are being studied.

In 3GPP, cellular mobile communication systems have been studied for some time, and the W-CDMA system has been standardized as a third-generation cellular mobile communication system. In addition, HSDPA (High-Speed Downlink Packet Access) that further improves the communication speed has been standardized and the service is being operated. Currently, in 3GPP, the evolution of the third generation radio access technology, that is, Long Term Evolution (hereinafter referred to as “LTE”) and LTE Advanced (hereinafter referred to as “LTE-A”) for further higher communication speeds. Is also being studied.

In uplink data transmission in LTE, a communication system based on SC-FDMA (Single-Carrier-Frequency-Division-Multiple Access) based on resources allocated from a base station apparatus is employed. Specifically, the modulated transmission signal is converted into a frequency domain signal by DFT (Discrete Fourier Transformation), mapped to the frequency resource allocated by the base station apparatus, and then timed by IDFT (Inverse DFT). The signal is converted into an area signal and transmitted to the base station apparatus. Here, the uplink data is passed from the upper layer, corresponds to data in which the meaning of each bit is not interpreted in the physical layer, and is referred to as UL-SCH (Uplink Shared Channel) defined in the transport channel. And Data that is actually transmitted is obtained by performing processing such as encoding on the UL-SCH.

On the other hand, in LTE uplink, information on downlink reception quality information (CQI: Channel ： Quality Indicator), information on downlink signal transmission signal preprocessing (PMI: Precoding Matrix Indicator), and downlink signal MIMO (Multiple Input 多重 Multiple Output) Control information such as spatial multiplexing number information (RI: Rank Indicator) when spatial multiplexing is applied is also transmitted. These pieces of control information can be transmitted using PUSCH (Physical-Uplink-Shared-Channel) simultaneously with UL-SCH, or can be transmitted independently using PUSCH without including UL-SCH.

FIG. 6 is a diagram showing the relationship between resource management and channels divided by time and frequency in LTE uplink. In each figure, each horizontal axis represents time, and the vertical axis represents frequency. As shown in FIG. 6, the uplink resource mainly includes a physical uplink control channel (PUCCH) used for transmitting control information, and each mobile station apparatus mainly transmits data. Physical uplink shared channels (PUSCH: Physical-Uplink-Shared-Channel), each of which is expressed as a set of division units called resource blocks (RB: Resource-Block). The number of resource blocks in the frequency direction depends on the system bandwidth. In the time direction, a time unit occupied by one resource block is called one slot, and these two are collectively called one subframe. The PUSCH is allocated to the mobile station apparatus in resource block units in which two slots are paired.

FIG. 7 is a diagram illustrating an example of the configuration in one resource block of PUSCH in terms of frequency and time. In FIG. 7, one resource block is composed of seven SC-FDMA symbols (corresponding to one slot) and 12 subcarriers in the frequency direction, and is the minimum resource composed of one SC-FDMA symbol and one subcarrier. The unit is called a resource element (RE). The modulation symbols arranged in the resource element are converted into the time domain by processing such as FFT (Fast Fourier Transformation) in units of SC-FDMA symbols, and then transmitted from the mobile station apparatus to the base station apparatus. In PUSCH, it is determined that a reference signal for propagation path estimation at the time of demodulation (or also referred to as a pilot signal) is arranged in the third SC-FDMA symbol in FIG.

FIG. 8 is a diagram showing an example of mapping when UL-SCH, CQI, PMI, and RI described in Non-Patent Document 1 and Non-Patent Document 2 are scheduled at the same time. The horizontal axis represents time, and each corresponds to one SC-FDMA symbol. The vertical axis represents a sequence of modulation symbol sequences to be mapped, does not correspond to the frequency axis, is subjected to DFT processing for each SC-FDMA symbol, and is mapped to resources allocated on the frequency axis. As shown in FIG. 8, in LTE, an ACK / NACK is mapped to two SC-FDMA symbols adjacent to a reference signal, and an RI is mapped to an SC-FDMA symbol separated by two from the reference signal. The CQI is mapped to all SC-FDMA symbols excluding the reference signal.

On the other hand, in LTE, since the influence of errors on UL-SCH, ACK / NACK, CQI / PMI, and RI is different, different required qualities are set. For example, ACK / NACK and RI require higher quality than CQI / PMI, and CQI / PMI requires higher quality than UL-SCH. For this reason, in Non-Patent Document 2 and Non-Patent Document 3, it is determined that an offset from UL-SCH corresponding to the type of information is applied to the modulation scheme and coding rate.

Specifically, ACK / NACK and RI are always QPSK regardless of the UL-SCH modulation scheme. Also, the coding rate applied to ACK / NACK, RI, and CQI / PMI is determined by applying the offset notified from the base station apparatus to the coding rate applied to UL-SCH. As a result, information that requires different communication qualities can be transmitted simultaneously while satisfying the request. Note that LTE does not employ spatial multiplexing based on MIMO (Multiple Input Multiple Output) for the uplink, and this is not taken into consideration.

When the above conventional method is extended to MIMO spatial multiplexing, information with high required quality such as ACK / NACK and RI is also spatially multiplexed and transmitted. However, in spatial multiplexing, interference between spatial layers occurs based on separation imperfection between multiplexed layers. For this reason, there arises a problem that it is difficult to achieve the quality of information that requires high error rate characteristics.

The present invention has been made in view of such circumstances, and when two or more types of information having different required qualities are transmitted in allocated communication resources, communication that satisfies the required qualities is performed efficiently and easily. An object of the present invention is to provide a wireless communication system, a base station apparatus, and a mobile station apparatus.

(1) In order to achieve the above object, the present invention has taken the following measures. That is, the wireless communication system of the present invention is a wireless communication system that transmits and receives a plurality of types of signals having different required qualities between a base station apparatus and a mobile station apparatus using a MIMO (Multiple Input Multiple Multiple Output) system. Thus, according to the required quality of the signal, different numbers of spatially multiplexed sequences are selected, and based on the selected number of spatially multiplexed sequences, each signal is transmitted / received by the MIMO scheme.

In this way, since different spatial multiplexing sequences are selected according to the required quality of the signal, and each signal is transmitted / received by the MIMO scheme based on the selected spatial multiplexing sequence, the request can be made efficiently and easily. Communication that satisfies the quality can be implemented.

(2) Further, the wireless communication system of the present invention selects at least one of different modulation schemes or coding rates according to the required quality of the signal, and based on the selected modulation scheme or coding rate, Each of the signals is processed.

As described above, according to the required quality of the signal, at least one of different modulation schemes or coding rates is selected, and each signal is processed based on the selected modulation scheme or coding rate. Communication that satisfies the required quality can be carried out efficiently and simply.

(3) In the wireless communication system of the present invention, the number of spatially multiplexed sequences is uniquely determined according to a plurality of types of signals having different required qualities.

Thus, since the number of spatially multiplexed sequences is uniquely determined according to a plurality of types of signals having different required qualities, the number of spatially multiplexed sequences can be selected easily and quickly.

(4) Further, in the wireless communication system of the present invention, the number of spatially multiplexed sequences for the transmission signal sequence number information among the plurality of types of signals having different required qualities is one.

As described above, since the number of spatially multiplexed sequences for the transmission signal sequence number information among a plurality of types of signals having different required qualities is 1, interference between spatial layers based on separation incompleteness between multiplexed layers is present. Transmission information sequence number information can be transmitted and received between the base station apparatus and the mobile station apparatus without being generated.

(5) Also, the radio communication system of the present invention uses the SC-FDMA (Single-Carrier-Frequency-Division-Multiple-Access) method to transmit and receive signals having the same number of selected spatial multiplexing sequences with the same symbol. It is a feature.

As described above, since signals having the same number of selected spatial multiplexing sequences are transmitted and received using the same symbol using the SC-FDMA system, information that must be transmitted with a lower number of spatial multiplexing is limited. By concentrating on a region, for example, a specific SC-FDMA symbol, it is possible to reduce a decrease in efficiency of uplink data transmission.

(6) Moreover, the base station apparatus of the present invention is a base station apparatus that transmits and receives a plurality of types of signals having different required qualities using a MIMO (Multiple Input Input Multiple Output) method with a mobile station apparatus. An uplink spatial multiplexing information control unit that selects different numbers of spatially multiplexed sequences according to the required quality of the signal, and at least one of a different modulation scheme or coding rate according to the required quality of the signal An uplink modulation scheme / coding rate control unit to transmit, information indicating the number of selected spatial multiplexing sequences, and transmission indicating information indicating the selected modulation scheme or coding rate to the mobile station apparatus And a section.

In this way, the number of different spatial multiplexing sequences is selected according to the required quality of the signal, and at least one of the different modulation schemes or coding rates is selected according to the required quality of the signal, and the selected space is selected. Since the information indicating the number of multiplexed sequences and the information indicating the selected modulation scheme or coding rate are transmitted to the mobile station device, the mobile station device is based on the number of spatial multiplexed sequences, the modulation scheme or the coding rate. By transmitting the signal, communication that satisfies the required quality can be performed efficiently and easily.

(7) A mobile station apparatus according to the present invention is a mobile station apparatus that transmits and receives a plurality of types of signals having different required qualities with a base station apparatus using a MIMO (Multiple Input Input Multiple Output) system. An uplink spatial multiplexing information management unit that manages information indicating the number of spatially multiplexed sequences received from the base station apparatus; and an uplink modulation scheme that manages information indicating the modulation scheme or coding rate received from the base station apparatus -Based on the coding rate management unit and the information indicating the managed modulation scheme or coding rate, the transmission signal is modulated and / or coded according to the required quality, and is managed. A mobile station-side transmitter that transmits a transmission signal to the base station apparatus in the MIMO scheme with the number of spatially multiplexed sequences corresponding to the required quality based on the information indicating the number of spatially multiplexed sequences. It is characterized in Rukoto.

In this way, based on information indicating the managed modulation scheme or coding rate, the number of spatially multiplexed sequences managed by performing at least one of modulation and coding corresponding to the required quality on the transmission signal Since the transmission signal is transmitted to the base station apparatus by the MIMO scheme with the number of spatially multiplexed sequences corresponding to the required quality based on the information indicating that, it is possible to efficiently and easily perform communication that satisfies the required quality it can.

Advantageous Effects of Invention According to the present invention, when a mobile station apparatus transmits a plurality of types of information having different required qualities in communication resources allocated from the base station apparatus, it is efficient by applying different spatial multiplexing numbers to each. In addition, communication that satisfies the required quality can be performed easily.

It is a block diagram which shows schematic structure of the base station apparatus which concerns on this embodiment. It is a block diagram which shows schematic structure of the mobile station apparatus which concerns on this embodiment. 10 is a sequence chart in which transmission resources for transmitting UL-SCH, CQI, PMI, and RI are allocated from base station apparatus 200 to mobile station apparatus 300, and transmission is performed using the resources. It is a figure which shows the example by which UL-SCH, CQI, PMI, and RI were mapped. It is a figure which shows the example of the mapping in 2nd Embodiment. It is a figure which shows the example of another mapping. It is a figure which shows the relationship between the resource management divided | segmented by the time and frequency in the uplink of LTE, and a channel. It is a figure which shows the example which showed the structure in 1 resource block of PUSCH in a frequency and time. It is a figure which shows the example of mapping when UL-SCH, CQI, PMI, and RI described in the nonpatent literature 1 and the nonpatent literature 2 are scheduled simultaneously.

(First embodiment)
The mobile communication system according to the first embodiment of the present invention includes a mobile station device and a base station device. In the present embodiment, UL-SCH (Uplink Shared Channel), CQI (Channel Quality Indicator), and RI (Rank Indicator) are simultaneously transmitted from the mobile station apparatus to the base station apparatus through PUSCH (Physical Uplink Shared Channel). Is assumed. However, the present invention is not limited to CQI or RI, but can be similarly applied in a situation where two or more pieces of information having different required qualities are transmitted simultaneously, and other information signals may be transmitted.

FIG. 1 is a block diagram showing a schematic configuration of a base station apparatus according to this embodiment. As shown in FIG. 1, the base station apparatus 200 according to the present embodiment includes a transmission unit 210, a scheduling unit 220, a reception unit 230, and an antenna 240. The transmission unit 210 includes an encoding unit 211, a modulation unit 212, a mapping unit 213, and a wireless transmission unit 214. Also, the scheduling unit 220 includes an uplink transmission resource control unit 221, an uplink spatial multiplexing information control unit 222, an uplink modulation scheme / coding rate control unit 223, a downlink transmission resource control unit 224, and a downlink spatial multiplexing information control. 225 and a downlink modulation scheme / coding rate control unit 226. The reception unit 230 includes a radio reception unit 231, an uplink propagation path calculation unit 232, and an inverse mapping / demodulation processing unit 233. There are as many antennas 240 as necessary for transmitting downlink signals and receiving uplink signals.

The downlink data generated in the upper layer in base station apparatus 200 and transmitted to each mobile station apparatus and scheduling information for control information transmission output from scheduling section 220 are input to encoding section 211, respectively. Is encoded according to the control signal from the scheduling unit 220 and an encoded bit string is output. However, the control signal from the scheduling unit 220 represents information representing a coding rate or a coding scheme such as a turbo code or a tail biting convolutional code. In addition, a plurality of pieces of information may be combined and encoded, and each piece of information may be encoded separately.

The plurality of output bit strings of the encoding unit 211 are input to the modulation unit 212, each of which is modulated according to a control signal from the scheduling unit 220, for example, converted into BPSK, QPSK, 16QAM, and 64QAM symbols and output. The output of the modulation unit 212 is input to the mapping unit 213 together with the downlink scheduling and spatial multiplexing information provided from the scheduling unit 220, and transmission data is generated. Here, the transmission data refers to, for example, an OFDM signal, and the mapping operation corresponds to an operation corresponding to the frequency and time resources specified for each mobile station apparatus. If spatial multiplexing by MIMO is employed, this processing is performed in this block. Here, the control information refers to uplink or downlink resource allocation information, that is, transmission timing and frequency resource information, uplink or downlink signal modulation scheme and coding rate, and CQI and PMI for the mobile station apparatus. , RI transmission request, etc.

The signal generated by the mapping unit 213 is output to the wireless transmission unit 214. In the wireless transmission unit 214, it is converted into a form suitable for the transmission method, and if it is a communication method specifically compliant with OFDMA, IFFT (Inverse Fast Fourier Transformation) is performed on the signal in the frequency domain, A time domain signal is generated. The output signal of the wireless transmission unit 214 is supplied to the antenna 240 and transmitted from here to each mobile station apparatus.

The scheduling unit 220 manages and controls the control information from the higher layer and the control information transmitted from the base station apparatus 200, determines the resource allocation to each mobile station apparatus, the modulation scheme, the coding rate, and these operations. Control and output of control information are performed. With respect to the uplink, the uplink transmission resource control unit 221 manages uplink resources used by each mobile station apparatus and generates a control signal thereof. The uplink spatial multiplexing information control unit 222 manages information that can be calculated from the propagation path measurement signal transmitted from the mobile station apparatus, determines the number of multiplexed sequences of MIMO spatial multiplexing to be applied to uplink signal transmission, The control signal related to it is generated. The uplink modulation scheme / coding rate control unit 223 manages information that can be calculated from the channel measurement signal transmitted from the mobile station apparatus, and determines the modulation scheme and coding rate to be applied to uplink signal transmission. At the same time, a control signal associated therewith is generated.

In the present embodiment, the uplink spatial multiplexing information control unit 222 and the uplink modulation scheme / coding rate control unit 223 perform different operations depending on the type of uplink signal, that is, the required required quality. It is a feature. Specifically, if the uplink signal is composed of UL-SCH, CQI, and RI, the uplink spatial multiplexing information control unit 222 can set different spatial multiplexing numbers for each signal, and the uplink modulation scheme The coding rate control unit 223 can set a different modulation scheme / coding rate for each signal.

Regarding the downlink, the downlink transmission resource control unit 224 manages the downlink resource allocated to each mobile station apparatus and generates a control signal to be transmitted to each mobile station apparatus. The downlink spatial multiplexing information control unit 225 manages control information (for example, RI) transmitted from the mobile station apparatus or information that can be calculated therefrom, and determines the number of multiplexed sequences of MIMO spatial multiplexing to be applied to downlink signal transmission. At the same time, a control signal associated therewith is generated. The downlink modulation scheme / coding rate control unit 226 manages control information (for example, CQI or PMI) transmitted from the mobile station apparatus or information that can be calculated from the control information, and applies the modulation scheme and code applied to downlink signal transmission. At the same time as the conversion rate is determined, a control signal associated therewith is generated.

On the other hand, the signal transmitted from the mobile station apparatus is received by the antenna 240 and then input to the radio reception unit 231. The wireless reception unit 231 receives data and control signals, generates a digital signal corresponding to the transmission method, and outputs it. Specifically, if the OFDM method is adopted, after the received signal is converted from analog to digital, a signal subjected to FFT processing in units of processing time is output. Here, the radio reception unit 231 includes a signal for measuring the state of the uplink propagation path and a signal including information processed by an upper layer (for example, information to be managed as a data signal or control information). Are output as a first signal and a second signal, respectively.

The first output of the radio reception unit 231 is output to the uplink propagation path calculation unit 232. Here, information necessary for uplink signal scheduling, spatial multiplexing, modulation scheme, and coding rate determination is calculated and output to scheduling section 220.

The second output of the wireless reception unit 231 is output to the inverse mapping / demodulation processing unit 233. The inverse mapping / demodulation processing unit 233 demodulates and extracts a plurality of types of information transmitted from the mobile station apparatus using the mapping pattern, modulation scheme, and coding rate managed by the scheduling unit 220. Here, if spatial multiplexing is applied to the uplink signal and two or more types of information having different communication qualities are transmitted at the same time, the time and frequency position in which each signal is included are separated in advance, and scheduling is performed. In accordance with the control information input from unit 220, inverse mapping and demodulation processing using different modulation schemes, coding rates, and spatial multiplexing numbers are performed. Among the signals obtained by such processing, those processed in the upper layer are output to the upper layer, and control information managed by the scheduling unit 220, such as CQI and RI, is assigned to the scheduling unit. 220.

FIG. 2 is a block diagram showing a schematic configuration of the mobile station apparatus according to the present embodiment. As illustrated in FIG. 2, the mobile station device 300 includes a reception unit 310, a scheduling information management unit 320, a transmission unit 330, and an antenna 340. The reception unit 310 includes a wireless reception unit 311, a demodulation processing unit 312, and a downlink propagation path calculation unit 313. Also, the scheduling information management unit 320 includes an uplink transmission resource management unit 321, an uplink spatial multiplexing information management unit 322, an uplink modulation scheme / coding rate management unit 323, a downlink spatial multiplexing information management unit 324, a downlink modulation. A system / coding rate management unit 325 and a downlink transmission resource management unit 326 are provided. The antennas 340 are provided as many as necessary for transmitting uplink signals and receiving downlink signals. The transmission unit 330 includes an encoding unit 331, a modulation unit 332, a spatial multiplexing / mapping unit 333, and a wireless transmission unit 334.

When the downlink signal transmitted from the base station apparatus 200 is received by the antenna 340, the received signal is input to the radio reception unit 311. The wireless reception unit 311 performs processing according to the communication method in addition to analog / digital (A / D) conversion and the like, and outputs the result. Specifically, in the case of OFDMA, a time-series signal after A / D conversion is subjected to FFT processing, converted into a time / frequency domain signal, and output.

The output signal of the wireless reception unit 311 is input to the demodulation processing unit 312. At the same time, the demodulation processor 312 includes downlink signal scheduling information output from the scheduling information manager 320 (that is, information indicating where the signal addressed to the local station is allocated), the number of spatially multiplexed sequences, the modulation scheme, Control information such as a coding rate is also input, and demodulation processing is performed. The demodulated signals are classified according to the signal type, information processed in the upper layer is passed to the upper layer, and information managed by the scheduling information management unit is input to the scheduling information management unit 320. Is done. The downlink propagation path calculation unit 313 calculates management information such as the number of spatially multiplexed sequences applicable to the downlink, the modulation scheme, and the coding rate, using the propagation path calculation signal provided from the radio reception unit 311 as an input signal. To do. This management information is input to the scheduling information management unit 320.

The scheduling information management unit 320 manages the control information transmitted from the base station apparatus 200, and also performs management for transmitting the control information calculated by the mobile station apparatus 300 to the base station apparatus 200. The uplink transmission resource management unit 321 manages the uplink resource information of the own station transmitted from the base station apparatus 200 and performs transmission control of the uplink signal. Uplink spatial multiplexing information management section 322 manages the number of MIMO spatial multiplexing sequences transmitted from base station apparatus 200, and performs management when applying this value to an uplink signal.

The uplink modulation scheme / coding rate management unit 323 manages the modulation scheme and coding rate information applied to the uplink signal transmitted from the base station apparatus 200, and applies this value to the uplink signal. Manage. In this embodiment, the uplink spatial multiplexing information management unit 322 and the uplink modulation scheme / coding rate management unit 323 operate differently depending on the type of uplink signal, that is, the required quality required. It is said. Specifically, if the uplink signal is composed of UL-SCH, CQI, and RI, the uplink spatial multiplexing information management unit 322 can set different spatial multiplexing numbers for each signal, and the uplink modulation scheme The coding rate management unit 323 can set a different modulation scheme / coding rate for each signal.

Regarding the downlink, the downlink transmission resource management unit 326 manages information on downlink resource allocation transmitted from the base station apparatus 200 to the own station and controls extraction of signals transmitted to the own station. The downlink spatial multiplexing information management unit 324 determines the number of spatial multiplexing sequences to be applied to the downlink signal based on the propagation path information calculated from the downlink signal, and simultaneously generates a control signal (RI) related thereto. . The downlink modulation scheme / coding rate management unit 325 determines a modulation scheme and a coding rate to be applied to downlink signal transmission based on the propagation path information calculated from the downlink signal, and simultaneously controls a control signal ( CQI, PMI) is generated.

The transmission unit 330 transmits the uplink data, CQI, and other information simultaneously on the assigned uplink resource. The downlink data and the signal managed by the uplink spatial multiplexing information management unit 322 are supplied to the encoding unit 331 at the transmission timing, and the input signal is encoded at a different coding rate depending on the type. It is. The plurality of series of output signals are input to the modulation unit 332, and are modulated by different modulation schemes depending on the respective types. This output is output to the spatial multiplexing / mapping unit 333.

Spatial multiplexing / mapping unit 333 performs signal mapping according to the spatial multiplexing number for each transmission information and mapping position information input from scheduling information management unit 320. Specifically, when SC-FDMA is applied to the transmission method, a signal is mapped to the assigned frequency domain.

The signal mapped by the spatial multiplexing / mapping unit 333 is input to the wireless transmission unit 334. In the wireless transmission unit 334, these signals are converted into a signal form to be transmitted. Specifically, an operation of converting a frequency domain signal into a time domain signal by IFFT and providing a guard interval corresponds to this. The output of the wireless transmission unit 334 is supplied to the antenna 240.

FIG. 3 is a sequence chart in which transmission resources for transmitting UL-SCH, CQI, PMI, and RI are allocated from base station apparatus 200 to mobile station apparatus 300, and transmission is performed using these resources. Here, it is assumed that UL-SCH, CQI, PMI, and RI are simultaneously transmitted as information having different required qualities, but the information types are not limited to these, and other information is transmitted. It is possible to apply the same procedure as in this embodiment.

The base station apparatus 200 allocates resources for transmitting uplink data to the mobile station apparatus 300 and transmits a signal requesting to transmit CQI, PMI, and RI simultaneously (step S300). Step S300 may include information on a modulation scheme applied to uplink signal (UL-SCH) transmission, a coding rate, and the number of spatial multiplexing, and the difference value or difference from the UL-SCH value is calculated. Only the index to represent may be notified. Further, this difference value may be shared between the mobile station apparatus 300 and the base station apparatus 200 in a form described in a specification or the like in advance. Information regarding modulation schemes, coding rates, and spatial multiplexing numbers applied to CQI, PMI, and RI may be uniquely calculated from information applied to UL-SCH or may be explicitly notified. Furthermore, for the spatial multiplexing number, a specific value may be used for each specific information. For example, when the RI is transmitted, this always corresponds to transmission with the spatial multiplexing number set to 1. In this case, a fixed value described in a specification or the like is applied as the value to be used.

Before and after Step S300, the base station apparatus 200 transmits a known signal used for calculating CQI, PMI, and RI to the mobile station apparatus 300 (Step S301). Receiving step S301, the base station apparatus 200 calculates CQI, PMI, and RI, and at the same time, determines UL- according to the allocated resource size (eg, corresponding to the number of frequency subcarriers), modulation scheme, and coding rate. An SCH is generated (step S302). Next, for the generated information such as UL-SCH, CQI, PMI, RI, etc., the coding rate corresponding to the type of information is calculated from the information given by the process of step S300 (step S303). Encoding and modulation are performed for each information (step S304).

Here, a plurality of pieces of information may be encoded together, for example, a bit string obtained by serializing CQI and PMI may be generated and encoded. Next, the mapping position of each information is calculated in consideration of the number of symbols of each modulated information, and the mapping and spatial multiplexing signals are considered in consideration of the spatial multiplexing number given by the processing of step S300. Is generated (step S305).

FIG. 4 is a diagram showing an example in which UL-SCH, CQI, PMI, and RI are mapped. In FIG. 4, the part denoted by 400 is a diagram showing resource mapping on the assumption that the SC-FDMA scheme is adopted for the uplink, the horizontal axis shows time, and one unit is 1 SC-FDMA symbol. The vertical axis represents that signals (modulation symbols) in one SC-FDMA symbol are arranged in the frequency domain assigned to one mobile station apparatus 300. In this resource 400, there are a reference signal (RS: Reference signal) (401), UL-SCH (402), RI (403), CQI and PMI (404) used by the receiver for channel estimation. . Here, it is assumed that RI is transmitted with rank 1, and other information is transmitted with rank N (N> 1). Since the MIMO spatial multiplexing signal separation processing at the receiver is performed in the frequency domain, it is difficult to process information of different ranks within one SC-FDMA symbol. For this reason, the second and sixth SC-FDMA symbols including the RI are transmitted with rank 1, and the other SC-FDMA symbols are transmitted with rank N.

However, the rank of the SC-FDMA symbol that transmits the RI is not limited to 1, and may be defined to other values as long as the value is smaller than N. This can also define an offset value from N. For example, if the offset is 2, and N = 4, it is also possible to transmit RI at rank 2. Further, the offset value can be individually notified from the base station apparatus to each mobile station apparatus.

As shown in FIG. 3, the signal generated in this way is transmitted from the mobile station apparatus 300 to the base station apparatus 200 (step S308), and received (step S309), the base station apparatus 200 performs inverse mapping. Each information is extracted by the processing (step S310). Here, the inverse mapping processing includes processing related to separation when the transmission signal is spatially multiplexed. The signal that has been reverse-mapped and separated into the respective information (UL-SCH, CQI, PMI, RI) is decoded (step S311), and the transmitted bit string is extracted.

According to the above procedure, when a plurality of signals having different required qualities are transmitted, it is possible to perform communication employing a spatial multiplexing number that can satisfy each quality.

(Second Embodiment)
In the second embodiment, the base station apparatus and mobile station apparatus adopt the same configuration as in the first embodiment, and their operations are also performed according to the sequence chart shown in FIG. The difference from the first embodiment is the mapping of each information shown in FIG. 4 and the arrangement of the number of spatially multiplexed sequences applied to it. In FIG. 4, since the RI to be transmitted in rank 1 is mapped to two SC-FDMA symbols, UL-SCH that can be transmitted in rank N must be transmitted in rank 1, which is inefficient. . The purpose of this embodiment is to improve the inefficiency.

FIG. 5A is a diagram illustrating an example of mapping in the second embodiment. FIG. 5A shows an example in which UL-SCH, CQI, PMI, and RI are mapped. In this resource 400, there are a reference signal (RS: Reference signal) (401), UL-SCH (402), RI (403), CQI and PMI (404) used by the receiver for channel estimation. . Here, it is assumed that RI is transmitted with rank 1, and other information is transmitted with rank N (N> 1). In this embodiment, the SC-FDMA symbol to which the RI is mapped is limited to the second one, only this symbol is transmitted with rank 1, and the other SC-FDMA symbols are transmitted with rank N. If there is a remainder in the SC-FDMA symbol that transmits the RI, other information (UL-SCH, CQI, PMI) or the like may be mapped to that portion (501 and 502 in FIG. 5A). In that case, the lowest rank among the applied ranks is applied. In this case, UL-SCH mapped to 501 and 502 is transmitted in rank 1.

FIG. 5B is a diagram showing another example of mapping. In FIG. 5B, as still another example, not only RI but also CQI and PMI are transmitted in rank 1. In this case, by concentrating RI, CQI, and PMI on, for example, the third and fifth SC-FDMA symbols, the area that must be transmitted in the lower rank is reduced, and the UL-SCH area that can be transmitted in rank N is reduced. Can be set widely. The specific procedure is the same as that in the first embodiment, and is as described with reference to FIG.

It should be noted that it is possible to switch between the first embodiment and the second embodiment described above by providing a threshold value in advance. That is, the mapping shown in FIG. 4 and the mapping shown in FIG. 5A are switched. When the time diversity effect is significant, the mapping shown in FIG. 4 is used. On the other hand, when priority is given to improving the uplink data transmission efficiency over the time diversity effect, the mapping shown in FIG. 5A is used. It is possible to realize efficient communication. Also, the mapping shown in FIG. 4 and the mapping shown in FIG. 5A can be switched using the number of allocated resource blocks, that is, the frequency band as a threshold. As a result, it is possible to eliminate the notification of the change of the mapping method between the mobile station apparatus and the base station apparatus.

According to the above procedure, when a plurality of signals having different required qualities are transmitted, it is possible to perform communication employing a spatial multiplexing number that can satisfy each quality. Further, by concentrating information that must be transmitted with a reduced number of spatial multiplexing in a limited area, for example, a specific SC-FDMA symbol, it is possible to reduce a decrease in the efficiency of uplink data transmission.

In each of the embodiments described above, each function in the base station apparatus and a program for realizing each function in the mobile station apparatus are recorded on a computer-readable recording medium, and the recording medium is recorded on this recording medium. The base station apparatus and mobile station apparatus may be controlled by causing the computer system to read and execute the recorded program. The “computer system” here includes an OS and hardware such as peripheral devices.

Further, the “computer-readable recording medium” means a storage device such as a flexible disk, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” means that a program is dynamically held for a short time, like a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In this case, it is intended to include those that hold a program for a certain period of time, such as a volatile memory inside a computer system serving as a server or a client in that case. In addition, the program may be for realizing a part of the above-described functions, and may be capable of realizing the above-described functions in combination with a program already recorded in the computer system. .

The embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and the design and the like within the scope not departing from the gist of the present invention are also claimed. Included in the range.

200 base station apparatus 210 transmitting section 211 encoding section 212 modulating section 213 mapping section 214 radio transmitting section 220 scheduling section 221 uplink transmission resource control section 222 uplink spatial multiplexing information control section 223 uplink modulation scheme / coding rate control section 224 downlink transmission resource control unit 225 downlink spatial multiplexing information control unit 226 downlink modulation scheme / coding rate control unit 230 reception unit 231 radio reception unit 232 uplink propagation path calculation unit 233 inverse mapping / demodulation processing unit 240 antenna 300 Mobile station apparatus 310 Reception section 311 Radio reception section 312 Demodulation processing section 313 Downlink propagation path calculation section 320 Scheduling information management section 321 Uplink transmission resource management section 322 Uplink spatial multiplexing information management section 323 Uplink modulation scheme / coding Management unit 324 downlink spatial multiplexing information management unit 325 downlink modulation scheme and coding rate management unit 326 downlink transmission resource management unit 330 transmitting unit 331 coding unit 332 modulation unit 333 spatial multiplexing mapping unit 334 radio transmission unit 340 antenna

Claims

A wireless communication system that transmits and receives a plurality of types of signals having different required qualities using a MIMO (Multiple Input Multiple Output) scheme between a base station apparatus and a mobile station apparatus,
A wireless communication system, wherein a different number of spatially multiplexed sequences is selected according to the required quality of the signal, and each signal is transmitted and received by a MIMO scheme based on the selected number of spatially multiplexed sequences.
The method according to claim 1, wherein at least one of a different modulation scheme or coding rate is selected according to the required quality of the signal, and the processing of each signal is performed based on the selected modulation scheme or coding rate. Item 2. A wireless communication system according to Item 1.
The wireless communication system according to claim 1, wherein the number of spatially multiplexed sequences is uniquely determined according to a plurality of types of signals having different required qualities.
4. The wireless communication system according to claim 3, wherein among the plurality of types of signals having different required qualities, the number of spatially multiplexed sequences with respect to transmission signal sequence number information is one.
5. The system according to claim 1, wherein a signal having the same number of selected spatial multiplexing sequences is transmitted / received by using the same symbol by using SC-FDMA (Single Carrier Frequency Division Multiple Access). A wireless communication system according to claim 1.
A base station apparatus that transmits and receives a plurality of types of signals having different required qualities using a MIMO (Multiple Input Multiple Output) method with a mobile station apparatus,
An uplink spatial multiplexing information control unit that selects different numbers of spatially multiplexed sequences according to the required quality of the signal;
An uplink modulation scheme / coding rate control unit that selects at least one of different modulation schemes or coding rates according to the required quality of the signal;
A base station apparatus comprising: a transmitter that transmits information indicating the selected number of spatially multiplexed sequences and information indicating the selected modulation scheme or coding rate to the mobile station apparatus. .
A mobile station apparatus that transmits and receives a plurality of types of signals having different required qualities using a MIMO (Multiple Input Multiple Output) method with a base station apparatus,
An uplink spatial multiplexing information management unit for managing information indicating the number of spatial multiplexing sequences received from the base station device;
An uplink modulation scheme / coding rate management unit for managing information indicating a modulation scheme or a coding rate received from the base station apparatus;
Based on the information indicating the managed modulation scheme or coding rate, the transmission signal is modulated or coded according to the required quality, and the number of managed spatial multiplexing sequences is indicated. A mobile station apparatus comprising: a mobile station side transmission unit configured to transmit a transmission signal to the base station apparatus by a MIMO scheme with the number of spatially multiplexed sequences corresponding to required quality based on information.