JP2010200077A - Mobile communication system, base station device, mobile station device, and mobile communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently utilize orthogonal resources when assigning a plurality of orthogonal codes to reference signals. <P>SOLUTION: A base station device first assigns a resource for transmitting a CQI to a mobile station device (at 501) and transmits a CQI calculation signal to the device (at 503). The mobile station device calculates the CQI (at 504), performs diffusion, applies mapping to a frequency resource (at 505), performs antenna mapping (at 506), and transmits a signal in an assigned time resource to a base station device A (at 507). The base station device A receives the signal and performs receiving processing such as extraction of a reference signal, estimation of a channel, extraction of CQI information and decoding (at 508). The processing steps from 503 to 508 are performed several times after the step 501 of assignment of the CQI transmission resource, and the same processing is performed for M mobile station devices (M being the number of devices). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a communication technique, and more particularly to a transmission diversity technique and a reception technique for improving reception quality in a mobile communication system having a base station apparatus and a mobile station apparatus for transmission and reception.

  As a method for next-generation cellular mobile communication, the international standardization project 3GPP (3rd Generation Partnership Project) has developed W-CDMA (Wideband-Code Division Multiple Access) and GSM (Global System for Mobile). Network specifications 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. Also, HSDPA (High-Speed Downlink Packet Access), which further improves the communication speed, has been standardized and the service is operated. Currently, in 3GPP, the evolution of the third generation radio access technology (Long Term Evolution: hereinafter referred to as “LTE”) and LTE Advanced (hereinafter referred to as “LTE-A”) for further higher communication speeds are proposed. Is also being studied.

  In transmission of uplink control information in LTE, CDMA (Code Division Multiple Access) based on orthogonal resources allocated from a base station apparatus is employed. Specifically, in the transmission of uplink reception quality information CQI (Channel Quality Indicator) using the control channel, in the frequency resource divided assuming SC-FDMA (Single Carrier Frequency Division Multiple Access), CAZAC ( Code spreading using orthogonal codes obtained by performing cyclic shifts of different lengths on the time axis on the Constant Amplitude and Zero Auto-Correlation sequence is performed. The CAZAC sequence is a sequence having a constant amplitude and excellent autocorrelation characteristics in the time domain and the frequency domain. Since the amplitude is constant in the time domain, PAPR (Peak to Average Power Ratio) can be kept low.

  FIG. 9 and FIG. 10 are diagrams showing the principle of resource management divided by time and frequency in an LTE uplink control channel, where the horizontal axis represents time and the vertical axis represents frequency. As shown in FIG. 9, the uplink resource is a physical uplink control channel (PUCCH) used mainly to transmit control information and a physical for each mobile station apparatus to mainly transmit data. Each channel has an uplink shared channel (PUSCH), and each is expressed as a set of division units called resource blocks (RBs). 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 two of them are called one subframe. The allocation unit in the PUCCH is a subframe, and is hopped for each slot to obtain frequency diversity. Specifically, resource blocks X having the same numbers (shown by m in the figure) shown in FIG. 9 are assigned, and subframes are assigned so as to be arranged at both ends on the frequency axis.

  On the other hand, FIG. 10 is a diagram showing an example in which the configuration within one resource block (RB) X is shown on the frequency-time axis. In this example, one resource block is composed of 7 SC-FDMA symbols (corresponding to 1 slot), 12 subcarriers in the frequency direction, and a minimum resource unit consisting of 1 SC-FDMA symbol × 1 subcarrier. Is called a resource element (RE).

  The modulation symbol arranged in the resource element is 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 particular, when transmitting the above-mentioned CQI using PUCCH, one symbol of CQI (for example, 2-bit information for QPSK) is spread by an orthogonal sequence having a sequence length of 12, and is composed of 1 SC-FDMA symbol x 12 subcarriers. Placed in the resource element. Further, a reference signal (or also referred to as a pilot signal) for propagation path estimation at the time of demodulation is similarly arranged. Specifically, a known sequence is orthogonal with a sequence length of 12 between a transmitter and a receiver. It is spread by a code and arranged in a resource element composed of 1 SC-FDMA symbol x 12 subcarriers. In LTE, it is determined that reference signals are arranged at positions of SC-FDMA symbol numbers 1 and 5 in FIG.

  On the other hand, the mobile station apparatus in LTE was assumed to have one amplifier and a plurality of transmission antennas, but in LTE-A, adoption of transmission diversity using a plurality of amplifiers and transmission antennas is being studied. When transmission diversity is used, even if the characteristics of one propagation path are degraded, a gain can be obtained by using a propagation path in another state, and as a result, reception characteristics can be improved.

  Regarding transmission diversity applied to CQI transmission using PUCCH in LTE-A, in Non-Patent Document 1 below, a method such as STBC (Space Time Block Coding) is qualitatively used as a two-antenna transmission diversity technique for uplink control signals. It has been evaluated. Also in the following Non-Patent Document 2, application of a method called SCTD (Space Code Transmit Diversity) is being studied.

  STBC is a transmission diversity technique using a plurality of antennas, and is effective in improving transmission quality in a fading environment. The STBC generates and transmits a pair of transmission signals by using symbols over a plurality of antennas and continuous time. In the receiver, by processing the obtained signal, a signal obtained by combining the respective propagation paths with the maximum ratio can be obtained, which is effective in improving the reception quality. However, in the STBC, the receiver needs to know the number of propagation paths corresponding to the transmission antenna, that is, it is necessary to allocate the same number of orthogonal resources as the transmission antenna to the reference signal. In the resource allocation procedure in LTE, whether it is a reference or CQI information is transmitted (that is, regardless of the SC-FDMA symbol number), one orthogonal code (a cyclic shift process different in the time domain is applied to the CAZAC sequence). In order to assign two reference orthogonal codes, a transmission resource for CQI information that is not actually used is also assigned to the mobile station apparatus. Specifically, using FIG. 11, when mobile station apparatus A performs STBC, orthogonal code numbers 0 and 1 are assigned from the mobile station apparatus. The CQI information is transmitted by STBC with symbols of SC-FDMA symbol numbers 0, 2, 3, 4 and 6 using an orthogonal code of 0, but the reference is SC-FDMA symbol numbers 1 and 5 with symbols. Each transmit antenna transmits with a different orthogonal code. That is, the resources of SC-FDMA symbol numbers 0, 2, 3, 4, and 6 in orthogonal code number 1 are not used. The same applies to mobile station apparatuses B to F. That is, twelve orthogonal codes can be acquired by the cyclic shift process of the CAZAC sequence, but the number of code division multiplexing becomes 6, and the resource utilization efficiency cannot be improved.

  In order to solve this, the first and fifth references are code-division-multiplexed by block spreading using a sequence of [+1, +1], [+1, -1], so that two references are multiplexed. It is also proposed (see Non-Patent Document 3 below), but it is necessary to have two or more references in one slot, or information based on the phase difference between two references already specified in LTE There is also a problem that there is no matching with the transmission method.

  On the other hand, SCTD is a transmission diversity method in which a gain is obtained by assigning orthogonal codes to each transmission antenna and transmitting signals, and by combining transmission signals that can be received separately. This method has the advantage that the configuration of the receiver can be reduced from the case where there is no transmission diversity, and a gain equivalent to that of STBC that performs maximum ratio combining on the transmission side can be obtained. However, as shown in FIG. 12, in all SC-FDMA symbols, one mobile station apparatus uses the number of orthogonal resources corresponding to the number of transmission antennas, and the resource utilization efficiency is lower than STBC.

“UL MIMO Transmission LTE”, 3GPP TSG RAN WG1 # 54bis, R1-083684 “Evaluation of transmission diversity for PUCCH in LTE-A”, 3GPP TSG RAN WG1 # 54bis, R1-083862 “Evaluation of transmission diversity for PUCCH in LTE-A”, 3GPP TSG RAN WG1 # 55bis, R1-090135

  As described above, Non-Patent Documents 1 to 3 do not propose a transmission diversity scheme that improves the number of multiplexing in code division multiplexing while maintaining consistency with conventional LTE. Specifically, in the transmission diversity scheme by STBC, it is necessary to be able to separate reference signals, and it is necessary to allocate orthogonal resources according to the number of transmission antennas. However, in a system designed on the assumption that transmission diversity is not used, when a plurality of orthogonal codes used for reference signals are allocated, not only reference signals but also orthogonal resources of data signals that are not used in STBC are allocated. Has occurred, and the problem of inefficient use of orthogonal resources has occurred. An object of the present invention is to improve the efficiency of orthogonal resource utilization.

  The present invention is characterized in that an STBC is used and an orthogonal resource of a reference signal that is additionally required for the STBC is shared by a plurality of terminals.

  According to one aspect of the present invention, the mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses, and the mobile station apparatus transmits a control signal to which transmission diversity is applied and two or more reference signals corresponding to a transmission antenna. Is transmitted to the base station apparatus, and the control signal and the reference signal are code division multiplexed by orthogonal codes assigned from the base station apparatus, and the two or more reference signals are multiplexed. An orthogonal code is assigned from the base station device to the mobile station device, one orthogonal code is assigned to two or more mobile station devices, and different mobile station devices can transmit reference signals in a time division manner. A wireless communication system is provided that is used for transmission.

  The mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses, and the mobile station apparatus receives a control signal to which transmission diversity using the STBC scheme is applied and two or more reference signals corresponding to a transmission antenna. A wireless communication system in which the control signal and the reference signal are code division multiplexed by an orthogonal code assigned from the base station device, and the control signal and the reference signal are multiplexed to the two or more reference signals. Are assigned from the base station apparatus to the mobile station apparatus, one orthogonal code is assigned to two or more mobile station apparatuses, and different mobile station apparatuses transmit reference signals in a time division manner. A wireless communication system characterized by being used is provided. Considering the extension to LTE, it is suitable for STBC.

  The control signal preferably includes channel quality information, spatial multiplexing sequence information, or transmission signal preprocessing information. Further, it is preferable that the control signal is transmitted by the SC-FDMA method, and the signal spread by the orthogonal code is arranged in the frequency axis direction. The orthogonal code allocation information notified from the base station apparatus to the mobile station apparatus includes first information on which orthogonal code is used at which time to transmit the control information, and at which time. 2nd information of which orthogonal code is used and the reference signal corresponding to which transmitting antenna is transmitted is included. Here, time refers to an SC-FDMA symbol.

For orthogonal code allocation notified from the base station apparatus to the mobile station apparatus, at which time, using which orthogonal code to transmit the control information, the first information,
Management information on which reference signal corresponding to which transmit antenna is transmitted at which time and which orthogonal code is used and an index corresponding to the management information are managed by the mobile station device and the mobile station device, and the mobile station It is preferable that the allocation is performed by notifying the index from the device to the base station device.

  The mobile station apparatus may be classified into a plurality of groups, and the index received by the mobile station apparatus from the base station apparatus may be interpreted for different orthogonal code assignments depending on the group.

  The group is classified by the number of orthogonal codes used for reference signal transmission, and the mobile station apparatus that performs multiplex transmission of reference signals using N (N is an integer of 2 or more) orthogonal codes, Preferably, the reference signal is code division multiplexed using N orthogonal codes corresponding to the received index and transmitted to the base station apparatus. Further, the interpretation of the index notified from the base station apparatus to the mobile station apparatus may be changed every predetermined time unit. This means that the arrangement of the reference signal changes for each slot.

  According to another aspect of the present invention, the mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses, and the mobile station apparatus transmits a control signal to which transmission diversity is applied and two or more references corresponding to a transmission antenna. A base station apparatus in a wireless communication system that transmits a signal to the base station apparatus, and wherein the control signal and the reference signal are code division multiplexed by orthogonal codes assigned from the base station apparatus, the two or more There is provided a base station apparatus characterized in that an orthogonal code for multiplexing the reference signal is allocated to the mobile station apparatus, and one orthogonal code is allocated to two or more mobile station apparatuses.

  The mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses. The mobile station apparatus transmits a control signal to which transmission diversity is applied and two or more reference signals corresponding to a transmission antenna to the base station apparatus. The control signal and the reference signal are mobile station apparatuses in a radio communication system that are code division multiplexed by orthogonal codes allocated from the base station apparatus, and are allocated from the base station apparatus to the mobile station apparatus. One orthogonal code for multiplexing the two or more reference signals is assigned to two or more mobile station apparatuses, and is used for transmission of reference signals in a time division manner in different mobile station apparatuses. A featured mobile station apparatus is provided.

  According to another aspect of the present invention, the mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses, and the mobile station apparatus transmits a control signal to which transmission diversity is applied and two or more references corresponding to a transmission antenna. A signal is transmitted to the base station apparatus, and the control signal and the reference signal are communication methods in a radio communication system in which code division multiplexing is performed using orthogonal codes assigned from the base station apparatus, A step of transmitting a reference signal to the base station apparatus by code spreading multiplexing in one mobile station apparatus, and a step of assigning an orthogonal code for multiplexing the reference signal from the base station apparatus to the mobile station apparatus A step of assigning one orthogonal code to two or more mobile station apparatuses, and a step of using different mobile station apparatuses for transmitting reference signals by time division , A communication method characterized in that it comprises is provided.

  The present invention may be a program for causing a computer to execute the communication method described above. The program may be acquired by a transmission medium such as the Internet. The present invention may also be a recording medium for causing a computer to execute the above program.

  In the present invention, one code resource is shared by a plurality of mobile station apparatuses, and the orthogonal resource is allocated to each mobile station apparatus by dividing time (that is, SC-FDMA symbol). Thereby, orthogonal resources that cannot be used in STBC can be reduced, and the number of mobile station apparatuses capable of simultaneous multiplexing by CDMA can be increased.

It is a functional block diagram which shows the example of 1 structure of the base station apparatus by this Embodiment. It is a functional block diagram which shows the example of 1 structure of the mobile station apparatus by this Embodiment. It is the figure which compared the allocation of the conventional resource and the allocation of the resource by this Embodiment. It is the figure which represented typically the method of utilization of the allocated orthogonal code in the case of using two transmission antennas and using STBC for a transmission diversity system. FIG. 6 is a sequence chart diagram in which a CQI transmission resource is allocated from a base station apparatus to a mobile station apparatus, and CQI transmission is performed using the resource. FIG. 6A is a sequence diagram showing a process and a signal flow between the base station apparatus and the mobile station apparatus in the mobile communication system according to the second embodiment of the present invention, and FIG. (C) is a figure which shows the procedure at the time of assigning a spreading code series with respect to the mobile station apparatuses 1 and 2 which transmit CQI by the transmission diversity using STBC. It is a figure which shows the example of arrangement | positioning different from FIG.6 (c) regarding which SC-FDMA symbol arrange | positions a reference signal. It is a figure which shows the example which changes the position of RS for every slot in the 3rd Embodiment of this invention. It is a figure which shows the principle of the resource management divided | segmented by the time and frequency in the uplink control channel of LTE, An example showing a configuration in one resource block in terms of frequency and time is shown. It is a figure which shows the example of allocation of the code | symbol of the orthogonal code number to a mobile station apparatus. It is a figure which shows the example of allocation of the code | symbol of the orthogonal code number to a mobile station apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(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 this Embodiment, the case where the orthogonal resource of the same number as the number of antennas is allocated to the mobile station apparatus is shown. Here, a transmission diversity method applicable to CQI transmission using PUCCH in LTE will be described. However, the present invention is not limited to the CQI, but can be applied in the same manner as long as it is a communication method in which code spreading is performed in a predetermined frequency domain and other information signals may be transmitted. .

  The mobile communication system according to the first embodiment of the present invention includes a base station device and a mobile station device. FIG. 1 and FIG. 2 are functional block diagrams showing one configuration example of each of a base station apparatus and a mobile station apparatus according to the present embodiment.

  As shown in FIG. 1, base station apparatus A according to the present embodiment includes transmission section 210, scheduling section 220, reception section 230, and antenna 240. The transmission unit 210 includes an information multiplexing unit 211, a modulation unit 212, a mapping unit 213, and a wireless transmission unit 214. The scheduling unit 220 includes a control information transmission resource control unit 222, and the reception unit 230 includes a radio reception unit 231, an information extraction unit 232, a channel compensation / despreading unit 233, and a combining / demodulating unit 234. I have. There are as many antennas 240 as necessary for transmitting downlink signals and receiving uplink signals.

  The downlink data generated in the base station apparatus A and transmitted to each mobile station apparatus and the scheduling information for control information transmission output from the scheduling section 220 are input to the information multiplexing section 211, and each mobile station Data to be transmitted to the device is generated. However, downlink data does not necessarily exist, and only scheduling information may exist. Here, scheduling information refers to time resources (subframe numbers, that is, offsets and cycles from a certain reference), frequency resources (resource block numbers) used by each mobile station apparatus to transmit CQI. This is information indicating a code resource. Here, regardless of the CQI, the transmitted control information may be information such as the number of transmission sequences in spatial multiplexing, transmission signal preprocessing information, or the like, or information transmitted simultaneously.

  The signal output from the information multiplexing unit 211 is modulated by the modulation unit 212 under the designation of the scheduling unit 220 and converted into a signal format to be transmitted. Specifically, the bit string is modulated into a signal such as QAM or QPSK.

  The signal modulated by the modulation unit 212 is supplied to the mapping unit 213 and mapped to resources according to the designation of the scheduling unit 220. Specifically, in the case of OFDMA, it is mapped to a frequency and time resource specified for each mobile station device, and information broadcast to all mobile station devices is also mapped to a predetermined frequency and time resource.

  The output of the mapping unit 213 is supplied to the wireless transmission unit 214 and converted into a form suitable for the transmission method. Specifically, in the case of an OFDMA-based communication scheme, a time-domain signal is generated by performing IFFT (Inverse Fast Fourier Transform) on a frequency-domain signal. If spatial multiplexing by MIMO (Multiple Input Multiple Output) is adopted, this processing is performed in this block. The output signal of the wireless transmission unit 214 is supplied to the antenna 240, from which the signal is transmitted to each mobile station apparatus.

  The scheduling unit 220 receives control information from an upper layer, and performs resource allocation, modulation scheme, coding rate determination, and the like for each mobile station apparatus. In particular, the control information transmission resource control unit 221 has a function of generating and managing the above-described scheduling information. Conventionally, the control code transmission resource control unit 221 divides the SC-FDMA symbol unit into the SC-FDMA unit where the orthogonal code allocation was not performed. Thus, it can be assigned to different mobile station apparatuses. Specifically, referring to FIG. 3, in the conventional allocation method shown on the left, orthogonal code numbers 0 and 1 are assigned to mobile station apparatus A and orthogonal code is assigned to mobile station apparatus B in order to realize STBC. Although it was necessary to assign the orthogonal codes of No. 2 and No. 3 (corresponding to the cyclic shift value of the CAZAC sequence), in the method according to the present embodiment, all SC-FDMA symbols are assigned to the mobile station apparatus A. And orthogonal code number 2 in all SC-FDMA symbols are assigned to mobile station apparatus B, and orthogonal code number 0 in SC-FDMA symbol number 1 and 5 are assigned. It is possible to assign the orthogonal code of the orthogonal code number 1 in the SC-FDMA symbol numbers 2 and 4.

  A signal transmitted from the mobile station apparatus is received by the antenna 240 and then input to the radio reception unit 231. The wireless receiving unit 231 receives data and control signals, generates a digital signal corresponding to the transmission method, and outputs it. Specifically, in the case of an OFDM-based communication method, a signal subjected to FFT processing in units of processing time is output after analog conversion of the received signal.

  The output of the wireless reception unit 231 is input to the information extraction unit 232 and is divided for each type of information. Specifically, the received signal is divided for each data from each mobile station device, and among them, the control information managed by the control information transmission resource control unit 221 and the signal to the higher layer are separated. The

  The output of the information extraction unit 232 is input to the propagation path compensation / despreading unit 233. The propagation path compensation / despreading section 233 estimates the propagation path from the reference signal included in the input signal, compensates for the received signal, and simultaneously uses the orthogonal code managed by the control information transmission resource control section. To despread the input signal. If the reference signal is also spread, the propagation path is calculated after despreading based on the spread code information input from the scheduling unit 220. Here, the order of performing channel compensation and despreading is not limited. The propagation path compensation / despreading unit 233 performs output for each spreading code.

  The output of the propagation path compensation / despreading unit 233 is input to the synthesizing / demodulating unit 234, and a demodulating process for reproducing the transmitted bits is performed simultaneously with synthesizing a plurality of input sequences. Combining is a process for improving reception quality by performing weighted addition according to propagation path conditions. When the transmitted signal is CQI, the bit is passed to an upper layer and used for processing such as retransmission processing. Here, the processing order of the propagation path compensation / despreading unit 233 and the synthesis / demodulation unit 234 is not limited. Further, by using the MMSE (Minimum Mean Square Error) method in order to improve the reception quality, these processes can be performed simultaneously, and the type of the reception algorithm is not limited.

  On the other hand, as shown in FIG. 2, each mobile station apparatus B includes a reception unit 310, a scheduling information management unit 320, a transmission unit 330, and an antenna 240. The reception unit 310 includes a wireless reception unit 311, a propagation path compensation unit 312, a decoding processing unit 313, and a control information generation unit 317. The decoding processing unit 313 includes an error correction / detection unit 314, a demodulation unit 315, and an information extraction / separation unit 316. The schedule information management 320 includes a control information transmission resource management unit 321 and a control information management unit 322. The transmission unit 330 includes an information multiplexing unit 331, a modulation / spreading unit 332, a mapping unit 333, and a transmission diversity signal generation unit 334. The wireless transmission unit 335 is provided. There are as many antennas 240 as necessary for transmitting uplink signals and receiving downlink signals.

  When the downlink signal transmitted from the base station apparatus A is received by the antenna 240, this 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, the time-series signal after A / D conversion is subjected to FFT processing, converted into a time / frequency domain signal, and output.

  An output signal of the wireless reception unit 311 is input to the propagation path compensation unit 312, and propagation path estimation is performed using a reference signal or the like given to the input signal, and propagation path compensation is performed based on the estimation and output. .

  In addition, the output signal of the wireless reception unit 311 is input to the control information generation unit 317, and control information is generated. Specifically, if the control information is CQI, the reception quality is measured from the received downlink signal reference signal or the like. The same applies to the case of the number of spatially multiplexed sequences and the case of transmission signal preprocessing information. The output of the control information generation unit 317 is output to the schedule information management unit 320 and is managed by the control information management unit 322.

  The output of the propagation path compensation unit 312 is input to the decoding processing unit 313, which is demodulated based on the output of the schedule information management unit 320 and, if necessary, after error correction / detection, classified by type. The first output used for scheduling and the second output processed in the upper layer. In particular, when the scheduling information described above is received, it is output to the schedule information management unit 320 and managed by the control information transmission resource management unit 321.

  Here, the processing order of the information extraction / separation unit 316, the error correction / detection unit 314, and the demodulation unit 315 in the decoding processing unit 313 is not limited. For example, these processes may be performed before and after depending on the type of transmitted information, and these processes may be performed depending on the system.

  The transmission unit 330 transmits uplink control information such as uplink data and CQI. Here, for the sake of simplicity, the operation will be described using an example in which only the CQI signal is transmitted. The CQI signal managed by the downlink data and control information management unit 322 is supplied to the information multiplexing unit 331 at the transmission timing. The information multiplexing unit 331 performs processing for transmitting the input information at the same time. Here, it is assumed that only the CQI is transmitted using the orthogonal resource transmitted from the base station apparatus A. The CQI signal input to the information multiplexing unit 331 is supplied to the modulation / spreading unit 332.

  Modulation / spreading section 332 modulates / spreads the signal of information multiplexing section 331 using the transmission resource supplied from schedule information management section 320.

  FIG. 4 is a diagram schematically showing how to use the assigned orthogonal code when the number of transmission antennas is two and STBC is used for the transmission diversity scheme. In this case, since two orthogonal codes can be used in SC-FDMA symbols 1 and 5, reference signals are transmitted in these SC-FDMA symbols. That is, the reference signal of the transmission antenna 1 is spread with the orthogonal code of the orthogonal code number 0, and the reference signal of the transmission antenna 2 is spread with the orthogonal code of the orthogonal code number 1. Other orthogonal codes, that is, orthogonal resources with orthogonal code number 0 and SC-FDMA symbol numbers 0, 2, 3, 4, and 6, are used to transmit CQI symbols and are spread with this code.

  The output of the modulation / spreading unit 332 is output to the mapping unit 333, mapped according to the transmission diversity scheme, and the number of signals corresponding to a plurality of transmission antennas is output.

  The signal mapped by the mapping unit 333 is input to the transmission diversity signal generation unit 334. When STBC is used as a transmission diversity method, an input signal is mapped to each antenna based on STBC and output to radio transmission section 335. In the wireless transmission unit 335, 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 335 has N sequences, and each is supplied to the N antennas 240.

  FIG. 5A is a sequence chart diagram in which a CQI transmission resource is allocated from the base station apparatus to the mobile station apparatus, and CQI transmission is performed using the resource. Here, it is assumed that STBC is performed with two transmission antennas in the mobile station apparatus. Note that the case where the number of transmission antennas in the mobile station apparatus is 2 will be described as an example here, but the same procedure as in this embodiment can be applied even when three or more reference signal orthogonal codes are assigned. Is possible.

  Base station apparatus A first allocates resources for transmitting CQI to mobile station apparatus B (501). The resource referred to here includes time resource, frequency resource, and sequence information used for spreading code. The time resource indicates at which timing the CQI can be transmitted, and the offset value and period from a certain reference point are notified from the base station apparatus A to the mobile station apparatus B. The frequency resource represents which resource block is used. The sequence information used for the spreading code is information indicating which orthogonal code can be used for which SC-FDMA symbol, and only the resource number is notified or corresponds to the resource number. This means that information to be notified is notified.

  As a specific example of release assignment by the process of 501, an operation of assigning a spread code sequence to mobile station apparatus B (1) and mobile station apparatus B (2) that transmit CQI by transmission diversity using STBC. This will be described with reference to FIG. Base station apparatus A assigns orthogonal code number 0 (corresponding to the cyclic shift value of the CAZAC sequence) in all SC-FDMA symbols to mobile station apparatus B (1). A signal for assigning the orthogonal code of the orthogonal code number 1 in the FDMA symbol numbers 1 and 5 is transmitted. Furthermore, this signal includes using SC-FDMA symbol numbers 1 and 5 as reference signals, using orthogonal code number 0 for antenna 1, and using orthogonal code number 1 for antenna 2. It is done. Further, the base station apparatus A allocates CAZAC resources of orthogonal code number 2 in all SC-FDMA symbols to mobile station apparatus B (2), and further, orthogonality in SC-FDMA symbol numbers 2 and 4 A signal for allocating the CAZAC resource with code number 1 is transmitted. Furthermore, this signal includes using SC-FDMA symbol numbers 2 and 4 as reference signals, using orthogonal code number 1 for antenna 1, and using orthogonal code number 2 for antenna 2. It is done. The allocation method at this time may use control signals of any layer, and details such as bit arrangement order and procedure are not limited.

  Next, the base station apparatus A transmits a CQI calculation signal that can be used for CQI to the mobile station apparatus B (503). Receiving this, the mobile station apparatus B calculates CQI (504), performs spreading with the orthogonal code assigned in the process of 501 and performs mapping to the frequency resource (505). Further, the mapped signal is subjected to antenna mapping corresponding to the transmission diversity method (506), and transmitted to the base station apparatus A in the allocated time resource (507). The base station apparatus A receives this signal and performs reception processing such as reference signal extraction, channel estimation, CQI information extraction, and demodulation (508). Here, since the position of the reference signal is notified to the mobile station apparatus B at the stage of the CQI transmission resource allocation process 501, the base station apparatus A can also use the information. The processes from 503 to 508 are performed a plurality of times after the CQI transmission resource allocation 501, and the same process is similarly performed for M mobile station apparatuses.

  With the above procedure, when the mobile station apparatus transmits control information by applying transmission diversity based on CDMA and STBC, it is possible to effectively use spreading code resources while obtaining diversity gain. As a result, it is possible to improve the number of mobile station apparatuses that can perform CDMA in one time / frequency resource. In this embodiment, CQI is taken as an example of control information to be transmitted, and its procedure and transmission method have been described. However, control information to be transmitted is not limited to CQI, and other information such as the number of spatially multiplexed sequences, transmission signal preprocessing information, etc. It can also be applied to the case of transmitting information.

(Second Embodiment)
FIG. 6A is a sequence diagram showing a process and a signal flow between the base station apparatus A and the mobile station apparatus B in the mobile communication system according to the second embodiment of the present invention. The present embodiment describes the procedure between the base station apparatus A and one mobile station apparatus B, but the same procedure is possible when a plurality of mobile station apparatuses communicate with the base station apparatus. is there. Further, the configurations of the base station apparatus A and the mobile station apparatus B can use the same configurations as those shown in FIGS.

  Here, the second embodiment of the present invention is different from the first embodiment in the CQI transmission resource allocation method allocated from the base station apparatus to the mobile station apparatus. In the first embodiment, which CAZAC sequence can be used for which SC-FDMA symbol can be used in detail and flexibly for the sequence information used for the spreading code notified as one of the CQI transmission resources. However, in this embodiment, the information to be expressed is compressed and transmitted to the mobile station apparatus as one index. The mobile station apparatus is characterized by uniquely interpreting the orthogonal resources that can be used from the index.

  A specific procedure will be described below with reference to FIG.

  The base station apparatus A first allocates resources for transmitting CQI to the mobile station apparatus B (501). The resource referred to here includes time resource, frequency resource, and sequence information used for spreading code. The time resource represents at which time timing the CQI can be transmitted, and the offset value and period from a certain reference point are notified from the base station apparatus to the mobile station apparatus. The frequency resource represents which resource block is used. The information on the sequence used for the spreading code is information indicating which CAZAC sequence can be used for which SC-FDMA symbol, and here, only a single index is notified.

  On the other hand, the mobile station apparatus B receiving this calculates a CAZAC sequence corresponding to the index, and interprets what information is transmitted using which CAZAC code of which SC-FDMA symbol (602). . Specifically, the procedure for assigning a spread code sequence to mobile station apparatuses B (1) and B (2) that transmit CQI with transmission diversity using STBC is shown in FIGS. 6 (b) and 6 (c). ) And will be described. Base station apparatus A transmits a signal representing index number 0 to mobile station apparatus B (1). No. 0 is assigned an orthogonal code of orthogonal code number 0 (corresponding to the cyclic shift value of the CAZAC sequence) in all SC-FDMA symbols, and further, an orthogonal code of SC-FDMA symbol numbers 1 and 5 is assigned. The number 1 orthogonal code and the SC-FDMA symbol numbers 1 and 5 are used as reference signals, the orthogonal code number 0 is used for the antenna 1, and the orthogonal code number 1 is used for the antenna 2. This is information that is shared by the base station apparatus A and the mobile station apparatus B in advance.

  Furthermore, the base station apparatus A transmits a signal representing No. 2 to the mobile station apparatus B (2). No. 2 assigns an orthogonal code of orthogonal code number 2 in all SC-FDMA symbols, and further assigns an orthogonal code of SC-FDMA symbol number 2 and orthogonal code number 1 in SC-FDMA. This is a number indicating that symbol numbers 2 and 4 are used as reference signals, orthogonal code number 1 is used for antenna 1 and orthogonal code number 2 is used for antenna 2. This interpretation is also information shared in advance between the base station apparatus A and the mobile station apparatus B. The allocation method at this time may use control signals of any layer, and details such as bit arrangement order and procedure are not limited.

  Note that the procedures from 503 to 508 in FIG. 6A are the same as those in the first embodiment, and thus the description thereof is omitted.

  With the above procedure, when the mobile station apparatus B transmits control information by applying transmission diversity based on CDMA and STBC, it is possible to effectively use spreading code resources while obtaining diversity gain. In addition, it is possible to reduce the control information transmitted from the base station apparatus A to the mobile station apparatus B, which occurs when assigning CQI transmission resources. Furthermore, when the present invention is applied to a system in which mobile station devices to which transmission diversity can be applied and mobile station devices to which transmission diversity is not applicable, the CQI transmission resource allocation mechanism is not changed, and the mobile station device classification It is also possible to mix both devices by changing the interpretation regarding the allocation of CQI resources.

  Further, in the present embodiment, an example of which SC-FDMA symbol is allocated to the reference signal is shown in FIG. 6C, but the arrangement of the reference signal is not limited to the example in FIG. 6C. For example, an arrangement as shown in FIG. 7 is also possible. That is, the orthogonal codes assigned from the base station apparatus may be assigned in any way as long as there is no collision between mobile station apparatuses. The reference signal does not need to be arranged with 2SC-FDMA symbols for each slot, and may be variably assigned according to the situation of the mobile station device (for example, the moving speed of the mobile station device or the distance from the base station).

  In this embodiment, CQI is taken as an example of control information to be transmitted, and its procedure and transmission method have been described. However, control information to be transmitted is not limited to CQI, but includes information on the number of spatially multiplexed sequences, transmission signal preprocessing information, and the like. It can also be applied when transmitting other information.

(Third embodiment)
FIG. 6 is also a sequence diagram showing processing and signal flow between the base station apparatus and the mobile station apparatus in the mobile communication system according to the third embodiment of the present invention. In the present embodiment, the procedure between the base station apparatus and one mobile station apparatus is described, but the same procedure can be performed when a plurality of mobile station apparatuses communicate with the base station apparatus. In addition, the configurations of the base station apparatus and the mobile station apparatus can be the same as the configurations shown in FIGS.

  Here, the sequence of the present embodiment is the same as the sequence of the second embodiment, but there is a difference in the reference signal resource allocation method allocated from the base station apparatus to the mobile station apparatus. That is, in the second embodiment, the position of the SC-FDMA symbol in which the reference signal is arranged is the same in the slot, but this embodiment is characterized in that the arrangement changes between the slots.

  A specific procedure will be described with reference to FIG.

  The base station apparatus A first allocates resources for transmitting CQI to the mobile station apparatus B (501). The resource referred to here includes time resource, frequency resource, and sequence information used for spreading code. The time resource represents at which time timing the CQI can be transmitted, and the offset value and period from a certain reference point are notified from the base station apparatus to the mobile station apparatus. The frequency resource represents which resource block is used. The sequence information used for the spreading code is information indicating which orthogonal code (cyclically shifted CAZAC sequence) can be used for which SC-FDMA symbol. Here, a single index is used. Only be notified. On the other hand, the mobile station apparatus that has received this calculates a cyclic shift CAZAC sequence corresponding to the index, and interprets what information is transmitted using which orthogonal code in which SC-FDMA symbol. (602).

  Specifically, the procedure for assigning a spread code sequence to mobile station apparatuses B (1) and B (2) that transmit CQI with transmission diversity using STBC is shown in FIGS. 8 (a) and 8 (b). Will be described. The base station apparatus transmits a signal indicating index 0 to the mobile station apparatus 1. In the first slot, No. 0 is assigned an orthogonal code of orthogonal code number 0 in all SC-FDMA symbols, and further, a CAZAC resource of orthogonal code number 1 in SC-FDMA symbol numbers 1 and 5 SC-FDMA symbol numbers 1 and 5 are used as reference signals, orthogonal code number 0 is used for antenna 1, and orthogonal code number 1 is used for antenna 2. In the second slot, CAZAC resources with orthogonal code number 0 in all SC-FDMA symbols are allocated, and further, CAZAC resources with orthogonal code number 1 in SC-FDMA symbol numbers 2 and 4; This indicates that SC-FDMA symbol numbers 2 and 4 are used as reference signals, orthogonal code number 0 is used for antenna 1, and orthogonal code number 1 is used for antenna 2. The procedures from 503 to 508, which are information shared in advance between the base station apparatus and the mobile station apparatus, are the same as those in the first and second embodiments.

  With the above procedure, when the mobile station apparatus transmits control information by applying transmission diversity using CDMA and STBC, it is possible to effectively use the spread code resource while obtaining diversity gain. In addition, when degradation due to the position of the reference signal occurs, the degradation can be reduced.

  Furthermore, in the present embodiment, an example of which SC-FDMA symbol is allocated to the reference signal is shown in FIG. 6C. However, the arrangement is not limited to the example shown in FIG. It is also possible to arrange like this. That is, the orthogonal codes assigned from the base station apparatus may be assigned in any way as long as there is no collision between mobile station apparatuses. Further, the reference signal does not need to be arranged with 2SC-FDMA symbols for each slot, and may be variably assigned according to the situation of the mobile station apparatus (for example, the moving speed of the mobile station apparatus or the distance from the base station apparatus). Good.

  In the present embodiment, CQI is taken as an example of control information to be transmitted, and its procedure and transmission method have been described. However, control information to be transmitted is not limited to CQI, and information on the number of spatially multiplexed sequences (RI ), Transmission signal preprocessing information (PMI), and other information such as ACK / NACK can be transmitted.

  In each of the above embodiments, for convenience of explanation, the case where the base station apparatus and the mobile station apparatus are one-to-one has been described as an example, but there may be a plurality of base station apparatuses and mobile station apparatuses. . Further, the mobile station device is not limited to a moving terminal, and may be realized by mounting the function of the mobile station device on a base station device or a fixed terminal.

  In each of the embodiments described above, the orthogonal code by the cyclic shift of the CAZAC sequence has been described as an example. However, the orthogonal code sequence is not limited to this, and any orthogonal code can be used. Can be used.

  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 this recording medium The base station apparatus and the mobile station apparatus may be controlled by causing the computer system to read and execute the program recorded in (1). The “computer system” here includes an OS and hardware such as peripheral devices.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” 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. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system. .

  Although the embodiments of the present invention have been described in detail with reference to the drawings, 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 patented. Included in the claims.

  The present invention is applicable to mobile communication devices.

A ... base station apparatus, 210 ... transmission unit, 211 ... information multiplexing unit, 220 ... scheduling unit, 230 ... reception unit, 212 ... modulation unit, 213 ... mapping unit, 214 ... radio transmission unit, 220 ... scheduling unit, 222 ... Control information transmission resource control unit, 230 ... reception unit, 231 ... radio reception unit, 232 ... information extraction unit, 233 ... propagation path compensation / despreading unit, 234 ... synthesis / demodulation unit, 240 ... antenna, B ... mobile station apparatus , 310 ... receiving unit, 311 ... wireless receiving unit, 312 ... propagation path compensating unit, 313 ... decoding processing unit, 314 ... error correcting / detecting unit, 315 ... demodulating unit, 316 ... information extracting / separating unit, 317 ... control information Generating unit, 320 ... scheduling information management unit, 321 ... control information transmission resource management unit, 322 ... control information management unit, 330 ... transmission unit, 331 ... information multiplexing unit, 33 ... modulation and spreading section, 333 ... mapping unit, 334 ... transmission diversity signal generating unit, 335 ... wireless transmission unit.

Claims (13)

The mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses, and the mobile station apparatus transmits a control signal to which transmission diversity is applied and two or more reference signals corresponding to transmission antennas to the base station apparatus. The control signal and the reference signal are code division multiplexed by orthogonal codes assigned from the base station apparatus,
Orthogonal codes for multiplexing the two or more reference signals are allocated from the base station apparatus to the mobile station apparatus, and one orthogonal code is allocated to two or more mobile station apparatuses. A radio communication system, wherein a station apparatus is used for transmitting a reference signal in a time division manner. The mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses. The mobile station apparatus receives a control signal to which transmission diversity using the STBC scheme is applied and two or more reference signals corresponding to a transmission antenna. A wireless communication system in which the control signal and the reference signal are code division multiplexed by orthogonal codes assigned from the base station device,
Orthogonal codes for multiplexing the two or more reference signals are allocated from the base station apparatus to the mobile station apparatus, and one orthogonal code is allocated to two or more mobile station apparatuses. A radio communication system, wherein a station apparatus is used for transmitting a reference signal in a time division manner.   The wireless communication system according to claim 1 or 2, wherein the control signal includes channel quality information, spatial multiplexing sequence information, or transmission signal preprocessing information. The radio communication system according to claim 1 or 2, wherein the control signal is transmitted by an SC-FDMA scheme, and the signal spread by the orthogonal code is arranged in a frequency axis direction. The orthogonal code allocation information notified from the base station apparatus to the mobile station apparatus is:
First information on which orthogonal code is used to transmit the control information at which time;
5. The second information as to which orthogonal code is used at which time and a reference signal corresponding to which transmission antenna is transmitted. 5. Wireless communication system. About assignment of orthogonal codes to be notified from the base station apparatus to the mobile station apparatus,
First information on which orthogonal code is used to transmit the control information at which time;
Management information as to which reference signal corresponding to which transmit antenna is transmitted at which time at which orthogonal code is used and an index corresponding to the management information are managed by the mobile station device and the mobile station device,
5. The radio communication system according to claim 1, wherein the allocation is performed by notifying the index from the mobile station apparatus to the base station apparatus. The radio according to claim 6, wherein the mobile station apparatus is classified into a plurality of groups, and the index received by the mobile station apparatus from the base station apparatus interprets different orthogonal code assignments depending on the group. Communications system. The group is classified by the number of orthogonal codes used for transmission of reference signals,
A mobile station apparatus that performs multiplex transmission of reference signals using N (N is an integer of 2 or more) orthogonal codes code-divides the reference signal using N orthogonal codes corresponding to the received index The radio communication system according to claim 7, wherein the radio communication system multiplexes and transmits to the base station apparatus. About interpretation of the index notified from the base station device to the mobile station device,
The radio communication system according to any one of claims 6 to 8, wherein the radio communication system changes every predetermined time unit. The mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses, and the mobile station apparatus transmits a control signal to which transmission diversity is applied and two or more reference signals corresponding to transmission antennas to the base station apparatus. The control signal and the reference signal are base station apparatuses in a radio communication system that are code division multiplexed by orthogonal codes assigned from the base station apparatus,
A base station apparatus, wherein an orthogonal code for multiplexing the two or more reference signals is allocated to the mobile station apparatus, and one orthogonal code is allocated to two or more mobile station apparatuses. The mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses, and the mobile station apparatus transmits a control signal to which transmission diversity is applied and two or more reference signals corresponding to transmission antennas to the base station apparatus. The control signal and the reference signal are mobile station apparatuses in a radio communication system in which code division multiplexing is performed using orthogonal codes allocated from the base station apparatus,
One orthogonal code for multiplexing the two or more reference signals allocated from the base station apparatus to the mobile station apparatus is allocated to two or more mobile station apparatuses, and time is different in different mobile station apparatuses. A mobile station apparatus that is used for transmission of a reference signal by division. The mobile station apparatus includes a base station apparatus and two or more mobile station apparatuses, and the mobile station apparatus transmits a control signal to which transmission diversity is applied and two or more reference signals corresponding to transmission antennas to the base station apparatus. The control signal and the reference signal are communication methods in a radio communication system in which code division multiplexing is performed using orthogonal codes assigned from the base station device,
Transmitting the two or more reference signals to the base station apparatus by code spreading multiplexing in one mobile station apparatus;
Assigning orthogonal codes for multiplexing the reference signal from the base station apparatus to the mobile station apparatus;
Assigning one orthogonal code to two or more mobile station devices;
And a step of using different mobile station apparatuses for transmitting reference signals in a time division manner.   A program for causing a computer to execute the communication method according to claim 12.

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