CN103166692B - Receiving device - Google Patents

Abstract

The invention discloses a receiving device. The receiving device comprises a receiving part, a control part and a transmitting part, wherein the receiving part is used for receiving information transmitted from the transmitting device and related with weight vectors; the control part is used for selecting proper weight vectors from all the weight vectors under the condition that assignment of candidates of the weight vectors and assignment of the weight vectors do not exist in the information related with the weight vectors, selecting proper weight vectors from the weight vectors assigned as the candidates under the condition that the assignment of the candidates of the weight vectors exists in the information related with the weight vectors, and selecting the assigned weight vectors under the condition that the assignment of the weight vectors exists in the information related with the weight vectors; and the transmitting part is used for transmitting the weight vectors selected by the control part and quality information aiming at the selected weight vectors to the transmitting device.

Description

receiving device

The patent application of the present invention is the title of the invention "transmission device, transmission control method and communication device", the application date is December 05, 2007, the international application number is "PCT/JP2007/073465", and the national application number is "200780101784.5". A divisional application of an invention patent application.

technical field

The present invention relates to a transmission device, a transmission control method, and a communication device, and more particularly, to a transmission device that wirelessly transmits a transmission signal using a plurality of antennas, a transmission control method, and a communication device that receives the transmission signal.

Background technique

Currently, wireless communication systems such as mobile phone systems and wireless LANs (Local Area Networks) are widely used. In addition, in order to cope with the increase in access to the Internet and the use of music/video distribution services by wireless communication terminals such as mobile phones, development of higher-speed/larger-capacity wireless communication systems is underway. For example, in the 3GPP (3rd Generation Partnership Project) that standardizes mobile phone systems, studies on the specifications of next-generation mobile phone systems such as LTE (Long Term Evolution) are underway.

Here, as one of technologies for realizing a high-speed/large-capacity mobile communication system, there is a multi-antenna transmission technology for wirelessly transmitting a transmission signal using a plurality of antennas. As a multi-antenna transmission technique, various methods can be considered depending on how to use each antenna. For example, a diversity method that transmits signals of the same content from multiple antennas to improve wireless communication quality, a MIMO (Multiple Input Multiple Output, Multiple Input Multiple Output) multiplexing method that transmits signals of different content from each antenna to increase the transmission rate, A beamforming method in which antenna gain is increased by outputting directional beams from each antenna in the direction where a receiving device exists.

When multiplexed transmission of transmission signals addressed to a plurality of receiving apparatuses is performed using a plurality of antennas, the transmitting apparatus weights the transmission signals addressed to each receiving apparatus using a coefficient sequence (weight vector) for adjusting the phase and amplitude. This enables multiplexed transmission using some or all of the multiple antennas. In this case, it is preferable that the transmitting device dynamically assigns the weight vector to the receiving device at the time of transmission so that the communication quality is good. Allocating weight vectors in consideration of the communication conditions of a plurality of receiving devices contributes to improving the throughput of the wireless communication system as a whole.

As the distribution control method of the transmission device, there is an open-loop control method (for example, refer to Patent Document 1), that is, the transmission device estimates the communication quality of the link (reverse (reverse) link) from each reception device to the transmission device, Autonomously decides to allocate. In addition, there is also a closed-loop control method (for example, refer to Patent Document 2), that is, each receiving device estimates the communication quality of the link (forward (forward) link) from the transmitting device to the receiving device, The device sends feedback information, and the sending device determines allocation according to the feedback information.

Patent Document 1: Japanese Patent Laid-Open No. 2003-235072

Patent Document 2: Japanese Unexamined Patent Publication No. 2006-81162

As a weight vector allocation control method of the transmission device, a method of determining allocation based on feedback information from each reception device is preferable in that better communication quality can be maintained. Because the communication quality of the forward link is not necessarily the same as that of the reverse link.

However, in the prior art described in the aforementioned Patent Document 2, there is a problem that the processing load at the time of allocation determination is heavy. Preferably, the transmission device selects an optimal combination of weight vectors capable of suppressing interference between transmission signals from a plurality of weight vector candidates, and distributes them to each transmission device. Therefore, each receiving device needs to perform communication quality estimation processing for a plurality of weight vector candidates so that the transmitting device can make an appropriate allocation decision. Therefore, an increase in the processing load, circuit scale, and power consumption of the receiving device becomes a problem. In addition, the amount of feedback information from the receiving device to the transmitting device also increases, which is a factor that compresses the communication bandwidth of the reverse link.

Contents of the invention

The present invention has been made in view of such a problem, and an object of the present invention is to provide a receiving device and a transmitting device capable of reducing the processing load when determining weight vector assignment.

In order to solve the above-mentioned problems, the present invention provides a receiving device, characterized in that the receiving device has: a receiving unit that receives information related to a weight vector transmitted from a transmitting device; When there is no designation of a candidate for a weight vector in the relevant information, select an optimal weight vector from among all the weight vectors, and if there is a designation of a candidate for a weight vector in the information related to the weight vector, select the optimal weight vector from the selected weight vector. selecting an appropriate weight vector from weight vectors designated as the candidates; and a transmission unit that transmits the weight vector selected by the control unit to the transmission device, the designated candidate belonging to a plurality of codebooks The weight vectors of the same codebook as the weight vectors assigned to other receiving apparatuses are weight vectors that can be used in parallel with the weight vectors assigned to other receiving apparatuses.

Furthermore, in the receiving apparatus, it is preferable that, when there is no designation of a candidate for a weight vector in the information related to the weight vector, a weight vector is selected from all weight vectors based on an estimation result of communication quality, and the weight vector is selected at When the information related to the weight vector includes the designation of the candidate of the weight vector, the weight vector is selected from the weight vectors designated as the candidate based on the estimation result of the communication quality.

Furthermore, in the receiving device, it is preferable that the information related to the weight vector is received by the receiving unit as a control signal.

According to the reception device described above, the processing load for determining weight vector assignment can be reduced.

The above and other objects, features and advantages of the present invention will become apparent from the following description in association with the accompanying drawings showing preferred embodiments as examples of the present invention.

Description of drawings

FIG. 1 is a diagram showing the present embodiment.

FIG. 2 is a diagram showing the system configuration of the first embodiment.

Fig. 3 is a block diagram showing functions of the radio base station according to the first embodiment.

FIG. 4 is a block diagram showing functions of the mobile station according to the first embodiment.

FIG. 5 is a diagram showing the relationship between transmission signals and weight vectors.

FIG. 6 is a diagram showing a configuration example of a codebook.

FIG. 7 is a flowchart showing the procedure of the first multi-antenna communication control.

FIG. 8 is a flowchart showing the procedure of the second multi-antenna communication control.

FIG. 9 is a diagram showing an example of communication between a radio base station and a mobile station according to the first embodiment.

FIG. 10 is a diagram showing the system configuration of the second embodiment.

FIG. 11 is a diagram showing functions of a radio base station according to the second embodiment.

FIG. 12 is a diagram illustrating functions of a mobile station according to the second embodiment.

Fig. 13 is a diagram showing an example of communication between a radio base station and a mobile station according to the second embodiment.

Label description

10 transmitting device; 11a, 11b, 11c antenna; 12 control unit; 20, 30, 40 receiving device; 21, 31, 41 antenna; 22, 32, 42 quality estimation unit.

detailed description

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

FIG. 1 is a diagram showing the present embodiment. In the wireless communication system shown in FIG. 1 , a transmitting device 10 performs multi-antenna transmission of transmission signals to receiving devices 20 , 30 , and 40 using antennas 11 a , 11 b , and 11 c .

The transmitting device 10 has antennas 11 a , 11 b , and 11 c and a control unit 12 . The antennas 11 a , 11 b , and 11 c wirelessly transmit transmission signals to the receiving devices 20 , 30 , and 40 under the control of the control unit 12 . The control unit 12 assigns weight vectors for multi-antenna transmission to the receiving devices 20, 30, and 40, and controls the antennas 11a, 11b, and 11c to output wireless signals.

Specifically, first, the control unit 12 selects a first receiving device from among the receiving devices 20 , 30 , and 40 according to a predetermined criterion, and assigns a weight vector to the first receiving device. The first receiving device can be selected according to the priority of the packet data to be wirelessly transmitted or the communication quality. For example, the control unit 12 first assigns a weight vector most suitable for the receiving device to a receiving device that is to receive packet data with a high priority or a receiving device with good communication quality. Here, the weight vector assigned to the first receiving device may be determined based on feedback information from the first receiving device.

Next, the control unit 12 outputs information on weight vector candidates that can be used in parallel with the weight vector allocated to the first receiving device to a second receiving device different from the first receiving device. A weight vector having a low degree of interference with the weight vector assigned to the first receiving device is selected as a weight vector candidate. Furthermore, the information on the weight vector candidates may be wirelessly transmitted by the transmitting device 10 to the second receiving device using a forward link, or may be transmitted via another wireless device.

Then, the control unit 12 acquires feedback information on weight vector candidates from the second receiving device, and assigns a weight vector to the second receiving device based on the feedback information. In this case, the feedback information includes the estimation result of the reception quality related to the weight vector candidate notified by the control unit 12 .

Here, the antennas 11a, 11b, 11c and the receiving devices 20, 30, 40 may be associated one-to-one such that the antenna 11a outputs a signal for the receiving device 20 and the antenna 11c outputs a signal for the receiving device 40 . It is also possible to adjust the phase and amplitude in a many-to-many correspondence such that antennas 11a and 11b output signals to the receiving device 20 , and antennas 11b and 11c output signals to the receiving device 40 . This correspondence is defined using a weight vector.

Receiving devices 20, 30, and 40 have antennas 21, 31, and 41 and quality estimation units 22, 32, and 42, respectively. The antennas 21 , 31 , and 41 receive wireless signals output from at least a part of the antennas 11 a , 11 b , and 11 c of the transmitting device 10 . The quality estimating units 22, 32, 42 estimate the radio communication quality of the forward link based on an instruction from the transmitting device 10, and output feedback information indicating the estimation result.

Specifically, when the transmission device 10 does not specify a weight vector candidate, the quality estimation units 22 , 32 , and 42 perform communication quality estimation processing so that an optimal weight vector can be selected from all the weight vectors. On the other hand, when the transmission device 10 designates weight vector candidates, it may perform communication quality estimation processing within the range necessary to select an appropriate weight vector from the designated weight vector candidates. Then, the quality estimation units 22, 32, 42 output feedback information indicating the estimation results. Also, the feedback information may be wirelessly transmitted by the receiving devices 20, 30, 40 to the transmitting device using a reverse link, or may be transmitted via other wireless devices.

Here, as a specific example, consider a case where the receiving device 20 is selected as the first receiving device. In this case, first, the transmitting device 10 instructs the receiving device 20 to perform communication quality estimation processing without limiting the weight vector. In response to this instruction, the receiving device 20 performs communication quality estimation processing for all weight vectors included in a plurality of weight vector candidates (for example, M types of candidates), and transmits feedback information indicating the estimation results to the transmitting device 10 . Then, the transmitting device 10 assigns an optimal weight vector to the receiving device 20 based on the feedback information from the receiving device 20 .

Next, the transmitting device 10 specifies weight vector candidates (for example, N (N<M) types of candidates) that can be used in parallel with the weight vector assigned to the receiving device 20, specifies the weight vector candidates to the receiving devices 30 and 40, and instructs communication Estimated quality of processing. In response to this instruction, the receiving devices 30 and 40 perform communication quality estimation processing within the range of the designated weight vector candidates, and transmit feedback information indicating the estimation results to the transmitting device 10 . Then, the transmitting device 10 assigns appropriate weight vectors to the receiving devices 30 and 40 based on the feedback information from the receiving devices 30 and 40 .

Furthermore, the transmitting device 10 may simultaneously transmit an instruction of estimation processing to the receiving devices 30 and 40 as the second receiving device, and assign a weight vector, or may sequentially send an instruction of estimation processing one by one, and assign a weight vector.

According to such a wireless communication system, first, the transmitting device 10 selects the first receiving device from among the receiving devices 20, 30, and 40 according to a predetermined criterion, and assigns a weight vector to the first receiving device. Next, information on weight vector candidates that can be used in parallel with the weight vector assigned to the first receiving device is transmitted to a second receiving device different from the first receiving device among the receiving devices 20 , 30 , and 40 . Then, the second receiving device executes communication quality estimation processing within the range of the designated weight vector candidates, and returns feedback information to the transmitting device 10 . Then, the transmitting device 10 assigns a weight vector to the second receiving device based on the feedback information from the second receiving device.

This makes it possible to assign an optimal weight vector corresponding to the communication situation to the receiving device selected as the first receiving device among the receiving devices 20, 30, and 40. On the other hand, it is possible to limit the range of communication quality estimation processing for the receiving device selected as the second receiving device, so that processing load, circuit size, and power consumption can be suppressed. In addition, it is possible to suppress the amount of feedback information sent from the receiving devices 20 , 30 , and 40 to the transmitting device 10 , thereby suppressing the bandwidth for feedback information occupied by the entire communication bandwidth of the reverse link.

Furthermore, since the transmitting device 10 assigns a weight to the transmission signal so that the receiving device can receive it favorably, the receiving devices 20 , 30 , and 40 can basically obtain a desired received signal only by demodulating the received signal.

In addition, since the transmitting device 10 transmits a predetermined known signal (pilot signal) using a different subcarrier or code for each antenna, the receiving device 20 (30, 40) can obtain the transmission path information for each antenna, and thus can The optimal weight (for example, the weight with the best reception quality) is determined from the weight candidates based on the acquired channel information for each antenna.

[the first embodiment]

Next, the first embodiment will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing the system configuration of the first embodiment. The mobile communication system according to the first embodiment is a wireless communication system in which a wireless base station performs wireless communication with a plurality of mobile stations. This radio communication system includes a radio base station 100 and mobile stations 200, 200a, 200b, and 200c.

The radio base station 100 is a communication device that relays packet data between mobile stations 200 , 200 a , 200 b , and 200 c located within a range (cell) of radio waves and a mobile station of a communication partner. The radio base station 100 has four transmitting and receiving antennas. The radio base station 100 performs multi-antenna communication based on the precoding MIMO method with the mobile stations 200, 200a, 200b, and 200c using these four transmission and reception antennas.

The mobile stations 200 , 200a , 200b , and 200c are mobile terminal devices, such as mobile phones, that communicate with other mobile stations and computers via the radio base station 100 . The mobile stations 200, 200a, 200b, and 200c transmit packet data and control information to the radio base station 100 as radio signals. The mobile stations 200, 200a, 200b, and 200c receive packet data and control information transmitted to the mobile stations as radio signals by the radio base station 100. Here, the mobile stations 200, 200a, 200b, and 200c can receive some or all of the radio signals output from the four antennas of the radio base station 100, and can select/combine signals as necessary.

Fig. 3 is a block diagram showing functions of the radio base station according to the first embodiment. The wireless base station 100 has transmitting and receiving antennas 111, 112, 113, 114, antenna duplexers 121, 122, 123, 124, receiving units 131, 132, 133, 134, demodulating unit 141, channel decoding unit 142, and control information extracting unit 151. , user data extraction unit 152, reception quality estimation unit 153, communication control unit 161, codebook holding unit 162, scheduler 163, control information generation unit 171, user data generation unit 172, pilot signal generation unit 173, channel coding unit 181 , modulation unit 182 , multi-antenna control unit 183 , and transmission units 191 , 192 , 193 , and 194 .

The transmitting and receiving antennas 111, 112, 113, and 114 are common antennas for transmitting and receiving. The four transmitting and receiving antennas 111, 112, 113, and 114 are installed so that the spatial correlation between the antennas is low. For example, take measures such as making the antenna installation interval far larger than the carrier wavelength, using horizontal/vertical polarized waves, and the like.

The transmission/reception antenna 111 outputs reception signals from the mobile stations 200 , 200 a , 200 b , and 200 c to the antenna duplexer 121 , and wirelessly transmits transmission signals obtained from the antenna duplexer 121 . Similarly, the transmitting and receiving antennas 112, 113, and 114 output reception signals to the duplexers 122, 123, and 124, respectively, and wirelessly transmit transmission signals obtained from the duplexers 122, 123, and 124, respectively.

The antenna duplexers 121, 122, 123, and 124 are devices for separating transmission signals and reception signals. The antenna duplexer 121 outputs the reception signal obtained from the transmission/reception antenna 111 to the reception unit 131 , and outputs the transmission signal obtained from the transmission unit 191 to the transmission/reception antenna 111 . Similarly, antenna duplexers 122, 123, and 124 output received signals obtained from transmitting and receiving antennas 112, 113, and 134 to receiving sections 132, 133, and 134, respectively, and output received signals from transmitting sections 192, 193 to transmitting and receiving antennas 112, 113, and 114, respectively. , 194 to obtain the sending signal.

Receiving units 131 , 132 , 133 , and 134 convert received signals obtained from antenna duplexers 121 , 122 , 123 , and 124 into baseband signals, respectively, and output them to demodulation unit 141 . In order to perform this conversion process, the receiving units 131, 132, 133, and 134 have, for example, low noise amplifiers (LNA: Low Noise Amplifier), frequency converters, band-limiting filters, AD (Analog to Digital, analog-to-digital) converters, quadrature demodulator etc.

The demodulation unit 141 demodulates the baseband signals acquired from the reception units 131 , 132 , 133 , and 134 under the control of the communication control unit 161 , according to a demodulation scheme compatible with uplink communication. Then, the demodulation unit 141 outputs the demodulated signal to the channel decoding unit 142 .

The channel decoding unit 142 performs decoding processing on the demodulated signal acquired from the demodulation unit 141 under the control of the communication control unit 161 in accordance with a decoding method corresponding to uplink communication. For example, the channel decoding unit 142 performs deinterleave processing and error correction processing. Then, the channel decoding unit 142 outputs the obtained decoded data to the control information extraction unit 151 and the user data extraction unit 152 .

The control information extraction unit 151 extracts the control information generated by the mobile stations 200 , 200 a , 200 b , and 200 c from the decoded data acquired from the channel decoding unit 142 , and outputs it to the communication control unit 161 . Here, as the extracted control information, there are feedback information related to weight vector assignment, information indicating a measurement result of downlink communication quality, and the like.

The user data extraction unit 152 extracts user data from the decoded data acquired from the channel decoding unit 142 and takes it in. The imported user data is forwarded according to the destination as packet data.

The reception quality estimation unit 153 continuously estimates the communication quality of each uplink from the mobile stations 200 , 200 a , 200 b , and 200 c to the radio base station 100 based on the demodulated signal obtained from the demodulation unit 141 . For example, the communication quality is estimated from pilot signals intermittently transmitted by the mobile stations 200, 200a, 200b, and 200c. Then, the reception quality estimation unit 153 outputs the estimation result to the communication control unit 161 .

The communication control unit 161 controls operations in the radio base station 100 based on the control information acquired from the control information extraction unit 151 , the communication quality estimation result acquired from the reception quality estimation unit 153 , and instructions from the scheduler 163 .

For example, communication control unit 161 determines communication methods such as modulation and coding methods applicable to mobile stations 200, 200a, 200b, and 200c, and controls demodulation unit 141, channel decoding unit 142, channel coding unit 181, and modulation unit 182. Also, the communication control unit 161 refers to the codebook holding unit 162 to determine weight vectors to be assigned to the mobile stations 200 , 200 a , 200 b , and 200 c and controls the multi-antenna control unit 183 . In addition, the communication control unit 161 instructs the control information generation unit 171 to transmit control information to the mobile stations 200, 200a, 200b, and 200c as necessary.

The codebook holding unit 162 holds a codebook defining combinations of weight vectors that can be used in parallel. The codebook holding unit 162 notifies the multi-antenna control unit 183 of the weight vectors assigned to the mobile stations 200 , 200 a , 200 b , and 200 c under the control of the communication control unit 161 .

The scheduler 163 acquires the control information extracted by the control information extraction unit 151 and the estimation result of the reception quality estimation unit 153 via the communication control unit 161, and manages allocation of radio resources (resources determined by time slots or frequency bands) based on these information. Then, the scheduler 163 continuously notifies the communication control unit 161 of the radio resource assignment results to the mobile stations 200 , 200 a , 200 b , and 200 c.

The control information generation unit 171 generates control information for the mobile stations 200 , 200 a , 200 b , and 200 c used for communication control based on an instruction from the communication control unit 161 , and outputs the control information to the channel coding unit 181 . Here, as the control information transmitted in the downlink, there are information indicating a multi-antenna communication method, information indicating a feedback information request for assigning weight vectors, information indicating a user data encoding method, and uplink radio resource distribution information, etc.

The user data generation unit 172 generates user data addressed to the mobile stations 200 , 200 a , 200 b , and 200 c and outputs it to the channel coding unit 181 .

The pilot signal generator 173 generates a pilot signal of a predetermined signal sequence, and outputs it to the modulator 182 . The pilot signal is used, for example, for the mobile stations 200, 200a, 200b, and 200c to estimate downlink communication quality.

The channel coding unit 181 encodes the control information obtained from the control information generation unit 171 and the user data obtained from the user data generation unit 172 under the control of the communication control unit 161 according to a coding scheme compatible with downlink communication. For example, the channel coding unit 181 performs interleaving processing and error correction coding processing. Then, the channel coding unit 181 outputs the coded data to the modulation unit 182 .

The modulation unit 182 processes the coded data acquired from the channel coding unit 181 under the control of the communication control unit 161 according to the modulation scheme corresponding to the downlink communication. For example, the modulation unit 182 performs modulation processing such as QPSK (Quadrature Phase Shift Keying) or QAM (Quadrature amplitude modulation, quadrature amplitude modulation) and bit repetition processing. In addition, the modulation unit 182 inserts the pilot signal obtained from the pilot signal generation unit 173 into the modulated signal. Then, the modulation unit 182 outputs the modulated signal to the multi-antenna control unit 183 .

The multi-antenna control unit 183 performs weighting processing on the modulated signal acquired from the modulation unit 182 under the control of the communication control unit 161 . That is, the multi-antenna control unit 183 acquires the weight vectors assigned to the mobile stations 200, 200a, 200b, and 200c from the codebook holding unit 162, applies the weight vectors to modulated signals, and generates baseband signals for each transmit/receive antenna.

Then, the multi-antenna control unit 183 outputs the baseband signal corresponding to the transmitting and receiving antenna 111 to the transmitting unit 191 . Similarly, the multi-antenna control unit 183 outputs baseband signals corresponding to the transmitting and receiving antennas 112 , 113 , and 114 to the transmitting units 192 , 193 , and 194 , respectively.

Transmitters 191 , 192 , 193 , and 194 convert baseband signals acquired from multi-antenna control unit 183 into transmission signals for wireless transmission, and output them to antenna duplexers 121 , 122 , 123 , and 124 , respectively. In order to perform this conversion processing, the transmitting units 191, 192, 193, and 194 include, for example, quadrature modulators, DA (Digital to Analog) converters, frequency converters, band-limiting filters, power amplifiers, and the like.

Also, the pilot signal inserted by the modulation unit 182 is arranged to be orthogonal to each of the transmitting and receiving antennas. Thus, the mobile stations 200 , 200 a , 200 b , and 200 c can differentiate the radio signals output from the transmitting and receiving antennas 111 , 112 , 113 , and 114 to estimate communication quality.

FIG. 4 is a block diagram showing functions of the mobile station according to the first embodiment. The mobile station 200 has a transmitting and receiving antenna 211, a receiving antenna 212, an antenna duplexer 221, receiving units 231 and 232, a demodulation unit 241, a channel decoding unit 242, a control information extraction unit 251, a user data extraction unit 252, and a reception quality estimation unit 253. , feedback information generation unit 254 , communication control unit 261 , codebook holding unit 262 , control information generation unit 271 , user data generation unit 272 , pilot signal generation unit 273 , channel coding unit 281 , modulation unit 282 and transmission unit 291 . Furthermore, the mobile stations 200a, 200b, and 200c can also be realized with the same module configuration as the mobile station 200 .

The transmitting and receiving antenna 211 is a transmission/reception shared antenna. The transmission/reception antenna 211 outputs a reception signal from the radio base station 100 to the antenna duplexer 221 and wirelessly transmits a transmission signal obtained from the antenna duplexer 221 . On the other hand, the reception antenna 212 is a reception-only antenna. The receiving antenna 212 outputs a received signal from the radio base station 100 to the receiving unit 232 .

The antenna duplexer 221 is a device for separating transmission signals and reception signals. The antenna duplexer 221 outputs the reception signal obtained from the transmission/reception antenna 211 to the reception unit 231 , and outputs the transmission signal obtained from the transmission unit 291 to the transmission/reception antenna 211 .

The reception unit 231 converts the reception signal obtained from the antenna duplexer 221 into a baseband signal, and outputs it to the demodulation unit 241 . Similarly, the reception unit 232 converts the reception signal obtained from the reception antenna 212 into a baseband signal, and outputs it to the demodulation unit 241 . In order to perform this conversion process, the receiving units 231 and 232 include, for example, a low-noise amplifier, a frequency converter, a band-limiting filter, an AD converter, a quadrature demodulator, and the like.

The demodulation unit 241 performs diversity combination of the two baseband signals acquired from the reception units 231 and 232 , and performs demodulation processing according to a demodulation method corresponding to downlink communication under the control of the communication control unit 261 . Then, the demodulation unit 241 outputs the demodulated signal to the channel decoding unit 242 .

Here, the mobile station 200 does not perform the process of multiplying the received signal by the weight because the radio base station 100 side has already performed the process of multiplying the weight in advance. Of course, the weights to be multiplied on the radio base station 100 side may be weights that also reflect the characteristics of the transmission path.

In the case where diversity combining is not performed, the number of antennas may be one. In addition, when different signals are transmitted from a plurality of antennas of the radio base station 100, the first antenna and the second antenna of the mobile station 200 may be respectively used to transmit different signals. These signals are received and individually demodulated to perform MIMO reception.

The channel decoding unit 242 performs decoding processing on the demodulated signal acquired from the demodulation unit 241 under the control of the communication control unit 261 according to the decoding method corresponding to the downlink communication. For example, the channel decoding unit 242 performs deinterleave processing and error correction processing. Then, the channel decoding unit 242 outputs the obtained decoded data to the control information extraction unit 251 and the user data extraction unit 252 .

The control information extraction unit 251 extracts the control information generated by the radio base station 100 from the decoded data acquired from the channel decoding unit 242 , and outputs it to the communication control unit 261 . Here, the extracted control information includes information indicating a multi-antenna communication method, information indicating a feedback information request for assigning weight vectors, information indicating a user data encoding method, uplink radio resource allocation information, and the like.

The user data extraction unit 252 extracts user data from the decoded data acquired from the channel decoding unit 242 and takes it in. The acquired user data is reproduced in the mobile station 200 according to the data type. For example, audio playback is performed in the case of audio data, and screen display is performed in the case of text data or image data.

The reception quality estimation unit 253 continuously estimates the downlink communication quality from the radio base station 100 to the mobile station 200 based on the demodulated signal obtained from the demodulation unit 241 and the decoded data obtained from the channel decoding unit 242 . Then, the reception quality estimation unit 253 outputs the estimation result to the control information generation unit 271 .

Also, when the communication control unit 261 instructs to perform estimation processing for assigning weight vectors, the reception quality estimation unit 253 estimates the communication quality when each weight vector held by the codebook storage unit 262 is used. However, when the communication control unit 261 designates a weight vector candidate, the reception quality estimation unit 253 estimates the communication quality only for the designated weight vector. Then, the reception quality estimation unit 253 outputs the estimation result to the feedback information generation unit 254 .

The feedback information generation unit 254 determines one or more optimal weight vectors based on the estimation results obtained from the reception quality estimation unit 253 . Then, the feedback information generation unit 254 generates feedback information indicating the determination result, and outputs it to the control information generation unit 271 . Here, in order to determine the optimal weight vector, the number for identifying each weight vector is used in the feedback information.

The communication control unit 261 controls the operation of the mobile station 200 based on the control information acquired from the control information extraction unit 251 . For example, the communication control unit 261 determines a communication method such as a modulation method and a coding method adopted by the radio base station 100 based on the control information, and controls the demodulation unit 241 and the channel decoding unit 242 . Also, when acquiring control information indicating a feedback information request for assigning weight vectors, the communication control unit 261 instructs the reception quality estimation unit 253 to perform estimation processing. In addition, the communication control unit 261 instructs the control information generation unit 271 to transmit control information to the radio base station 100 as necessary.

The codebook holding unit 262 holds a codebook. The codebook held by the codebook holding unit 262 is the same as the codebook held by the radio base station 100 . The codebook holding unit 262 notifies the reception quality estimation unit 253 of the necessary weight vectors under the control of the communication control unit 261 .

The control information generation unit 271 generates control information addressed to the radio base station 100 used for communication control based on an instruction from the communication control unit 261 , and outputs it to the channel coding unit 281 . Here, as the control information transmitted in the uplink, there are information on the estimation result of the communication quality acquired from the reception quality estimation unit 253, feedback information acquired from the feedback information generation unit 254, and ACK (Acknowledgment, Acknowledgment)/NACK (NegativeAcknowledgment, non-acknowledgement), etc.

The user data generation unit 272 generates user data addressed to other mobile stations or computers, and outputs it to the channel coding unit 281 . As user data, there are voice data, text data such as e-mail data, image data, and the like, for example.

The pilot signal generator 273 generates a pilot signal of a predetermined signal sequence, and outputs it to the modulator 282 . The pilot signal is used, for example, for the radio base station 100 to estimate uplink communication quality.

The channel coding unit 281 encodes the control information obtained from the control information generation unit 271 and the user data obtained from the user data generation unit 272 under the control of the communication control unit 261 according to a coding scheme compatible with uplink communication. For example, the channel coding unit 281 performs interleaving processing and error correction coding processing. Then, the channel coding unit 281 outputs the coded data to the modulation unit 282 .

The modulation unit 282 processes the coded data acquired from the channel coding unit 281 under the control of the communication control unit 261 according to the modulation scheme corresponding to the uplink communication. For example, the modulation unit 282 performs modulation processing such as QPSK or QAM, and bit repetition processing. In addition, the modulation unit 282 inserts the pilot signal obtained from the pilot signal generation unit 273 . Then, the modulation unit 282 outputs the modulated signal to the transmission unit 291 .

The transmission unit 291 converts the modulation signal obtained from the modulation unit 282 into a transmission signal for wireless transmission, and outputs it to the antenna duplexer 221 . In order to perform this conversion process, the transmission unit 291 has, for example, a quadrature modulator, a DA converter, a frequency converter, a band-limiting filter, a power amplifier, and the like.

FIG. 5 is a diagram showing the relationship between transmission signals and weight vectors. In the multi-antenna control unit 183 of the radio base station 100, the weighting process shown in FIG. 5 is performed. That is, vector y representing a transmission signal is calculated as y=W with respect to a vector x representing a transmission flow which is a sequence of modulated signals to be transmitted and a matrix W representing a weight vector assigned to the mobile stations 200, 200a, 200b, and 200c. x.

Here, the size of the vector x is n (≥1), the size of the matrix W is m×n (m≥1), and the size of the vector y is m. m is the number of antennas used for transmission and n is the number of transmit streams transmitted simultaneously. Each column of the matrix W corresponds to one weight vector. Within the matrix W, weight vectors are combined to suppress interference between transmitted streams. In addition, each weight in the weight vector is a coefficient for adjusting the phase and amplitude when wirelessly transmitting the transmission stream, and can be expressed as a complex number.

In the weighting process, the jth (1≤j≤n) transmission stream in the vector x corresponds to the weight vector in the jth column in the matrix W. That is, the j-th transmission stream is multiplied by the weight vector in the j-th column, thereby determining that the j-th transmission stream is allocated to multiple antennas. Furthermore, one transmission stream may be associated with one mobile station, or a plurality of transmission streams may be associated with one mobile station. The latter means sending data of different contents to the same mobile station in parallel at the same time. In this case, a plurality of weight vectors are assigned to one mobile station.

FIG. 6 is a diagram showing a configuration example of a codebook. The codebook holding unit 162 of the radio base station 100 holds the codebook set shown in FIG. 6 . Also, the mobile stations 200 , 200 a , 200 b , and 200 c hold the same codebook set as the codebook holding unit 162 of the radio base station 100 . In this example, the number of transmission streams is set to 4, the number of weight vectors in each codebook is set to 4, and the number of codebooks is set to 8.

Each codebook is assigned a codebook number. Specifically, code numbers from 0 (binary number 000) to 7 (binary number 111) are assigned to the eight codebooks, respectively. Here, even if any two weight vectors belonging to the same codebook are used in parallel, interference between transmission streams is small. On the other hand, when any two weight vectors belonging to different codebooks are used in parallel, interference between transmission streams may increase.

In such a codebook set, each weight vector can be identified by a set consisting of a codebook number and a column number. For example, a weight vector such as (0.3780, −0.2698−j0.1578, 0.5957+j0.1578, 0.1587−j0.2411) can be specified using information such as codebook number 001+column number 1.

Next, the specific content of the communication control executed in the wireless communication system having the above configuration and data structure will be described.

FIG. 7 is a flowchart showing the procedure of the first multi-antenna communication control. Next, the processing shown in FIG. 7 will be described according to the step numbers.

[Step S11] The scheduler 163 of the wireless base station 100 judges the priority of the mobile stations 200, 200a, 200b, and 200c, and divides them into a first mobile station to which an optimal weight vector is preferentially assigned and other second mobile stations . Here, the priority of the mobile station is determined based on the QoS (Quality of Service) of the transmission stream, the priority of data such as the mobile station user, and the current communication state such as the communication quality or the moving speed of the mobile station. Then, the scheduler 163 outputs priority information to the communication control unit 161 .

In addition, in the following description, it is assumed that the mobile station 200 is determined to be the first mobile station, and the mobile stations 200a, 200b, and 200c are determined to be the second mobile station. In addition, only the mobile station 200a is representatively considered as the second mobile station.

[Step S12] The communication control unit 161 of the radio base station 100 instructs the control information generation unit 171 to request feedback information from the mobile station 200 determined to be the first mobile station in step S11. At this time, the communication control unit 161 does not limit the weight vectors to be communication quality estimation targets. The control information generation unit 171 generates control information corresponding to an instruction from the communication control unit 161 . This control information is wirelessly transmitted to the mobile station 200 .

[Step S13] The communication control unit 261 of the mobile station acquires the control information generated by the control information generation unit 171 of the radio base station 100 in step S12, and instructs the reception quality estimation unit 253 to estimate communication quality. At this time, the communication control unit 261 does not designate a weight vector to be estimated. The reception quality estimation unit 253 targets all the weight vectors held by the codebook holding unit 262 and estimates the communication quality when each weight vector is applied. Then, the reception quality estimation unit 253 outputs the estimation result to the feedback information generation unit 254 .

Furthermore, since signals (frequency, spreading code, etc.) transmitted from each antenna can be separated for each antenna, the radio base station 100 can perform channel estimation for each antenna and determine a weight vector with the best communication quality.

[Step S14] The feedback information generation unit 254 of the mobile station 200 generates feedback information based on the estimation result output by the reception quality estimation unit 253 in step S13. The feedback information includes the codebook number corresponding to the weight vector judged to be optimal based on the estimation result and the column number in the codebook (information capable of specifying the weight vector). Then, the feedback information generation unit 254 outputs the feedback information to the control information generation unit 271 . This feedback information is wirelessly transmitted to the radio base station 100 as control information.

[Step S15] The communication control unit 161 of the radio base station 100 acquires the feedback information generated by the feedback information generation unit 254 of the mobile station 200 in step S14. Then, the communication control unit 161 determines a weight vector to be assigned to the mobile station 200 based on the feedback information. Then, multi-antenna transmission to the mobile station 200 starts.

[Step S16] The communication control unit 161 of the radio base station 100 instructs the control information generation unit 171 to request feedback information from the mobile station 200a determined to be the second mobile station in step S11. At this time, the communication control unit 161 limits the weight vectors to be communication quality estimation targets to weight vectors belonging to the same codebook as the weight vectors allocated to the first mobile station in step S15.

The control information generation unit 171 generates control information corresponding to an instruction from the communication control unit 161 . This control information includes a codebook number as information indicating a weight vector to be estimated. The control information is wirelessly transmitted to the mobile station 200a. In addition, the control information may further include column numbers indicating weight vectors assigned to other mobile stations (or weight vectors not assigned to other mobile stations) in the designated codebook. In this case, the range of quality estimation processing performed by the mobile station 200a can be further limited.

[Step S17] The mobile station 200a performs the same processing as that performed by the mobile station 200 in step S13. However, the mobile station 200a is limited to the weight vectors in the codebook specified by the control information generated by the radio base station 100 in step S16 (depending on the content of the control information, all or part of the weight vectors in the codebook), the communication quality estimated processing.

[Step S18] Similar to the process performed by the mobile station 200 in step S14, the mobile station 200a wirelessly transmits feedback information indicating the result of the estimation process in step S17 to the radio base station 100 as control information. This feedback information includes a column number (information capable of specifying the weight vector) corresponding to the weight vector judged to be optimal based on the estimation result. Also, since the codebook number is specified by the control information from the radio base station 100, the codebook number may not be included in the feedback information, but the codebook number may be included for confirmation.

[Step S19] The communication control unit 161 of the radio base station 100 acquires the feedback information generated by the mobile station 200a in step S18. Then, the communication control unit 161 checks the weight vector most suitable for the mobile station 200a with weight vectors already assigned to other mobile stations, and determines whether there is a weight vector that can be assigned to the mobile station 200a. When there is a weight vector that can be assigned, the process proceeds to step S20. When there is no allocatable weight vector, the process proceeds to step S16, and the communication quality estimation process is executed again. In addition, in order to reduce the amount of processing, it is also possible to set a waiting time according to the state of the transmission path or the like before executing the estimation process again.

[Step S20] The communication control unit 161 of the radio base station 100 determines a weight vector to be assigned to the mobile station 200a. Then, multiplexing with the mobile station 200 is performed, and multi-antenna transmission to the mobile station 200a starts.

[Step S21] The communication control unit 161 of the radio base station 100 judges whether or not data transmission to the mobile station 200a is completed. When it is finished, the process proceeds to step S16, and the weight vector is reassigned to the second mobile station. If not finished, the process proceeds to step S22.

[Step S22] The communication control unit 161 of the radio base station 100 judges whether or not the data transmission to the mobile station 200 has been completed. When it ends, the process proceeds to step S21, and the selection process of the first mobile station is performed. In addition, when finished, the processing procedure is advanced to step S11, and it restarts from the determination of the priority. If not finished, the process proceeds to step S21.

In this way, the radio base station 100 first determines the priorities of the mobile stations 200, 200a, 200b, and 200c, and selects the first mobile station. Next, the radio base station 100 causes the first mobile station to estimate an optimal weight vector from the entire codebook, and assigns the weight vector. Then, the radio base station 100 allows mobile stations other than the first mobile station to estimate optimal weight vectors only for weight vectors belonging to the same codebook as the weight vector assigned to the first mobile station, and assigns weight vectors.

Furthermore, when there are a plurality of second mobile stations, the processing of the above steps S16 to S20 may be performed sequentially for each mobile station, or may be performed in parallel for a plurality of mobile stations. In addition, in the above-mentioned step S11, the second mobile stations may also be sorted according to the priority, and the weight vectors may be assigned in this order.

In addition, in the control method shown in FIG. 7, the weight vector allocation to the first mobile station is fixed until the data transmission to the first mobile station is completed, but the allocation time can also be set, and when the allocation time passes When redistribution processing.

FIG. 8 is a flowchart showing the procedure of the second multi-antenna communication control. Here, in steps S31 to S44 shown in FIG. 8 , the processing in steps S31 to S35 is the same as the processing in steps S11 to S15 described above, and the processing in steps S37 to S41 is the same as the processing in steps S16 to S20 described above, so descriptions are omitted.

[Step S36] The communication control unit 161 of the radio base station 100 sets the allocation time and the allocation frequency band to the mobile station 200 which is the first mobile station.

[Step S42] The communication control unit 161 of the radio base station 100 judges whether or not the data transmission to the mobile station 200a as the second mobile station has been completed. When the process ends, the process proceeds to step S37, and the weight vector is reassigned to the second mobile station. If not finished, the process proceeds to step S43.

[Step S43] The communication control unit 161 of the radio base station 100 judges whether or not the allocated time set to the mobile station 200 in step S36 has elapsed. If it has passed, the process proceeds to step S31, and the priority of the mobile station is determined again. If not, the process proceeds to step S44.

[Step S44] The communication control unit 161 of the radio base station 100 judges whether or not the data transmission to the mobile station 200 has been completed. When it ends, the process proceeds to step S32, and the weight vector is assigned to the mobile station 200 again. If not finished, the process proceeds to step S42.

In this way, the radio base station 100 first determines the priorities of the mobile stations 200, 200a, 200b, and 200c, and selects the first mobile station. Next, the radio base station 100 assigns a weight vector to the first mobile station, and sets an assignment time. Then, the radio base station 100 assigns weight vectors to mobile stations other than the first mobile station. Here, when the allocation time set for the first mobile station elapses, the radio base station 100 re-determines the priority of the mobile station even if the data transmission to the first mobile station continues, and reassigns the weight vector. In addition, the allocation time of the weight vector may also be set for the second mobile station.

Next, the flow of communication between the radio base station 100 and the mobile stations 200, 200a, 200b, and 200c when weight vector allocation control is performed using the method shown in FIG. 8 will be described.

FIG. 9 is a diagram showing an example of communication between a radio base station and a mobile station according to the first embodiment. This example is a case where a time division duplex (TDD: Time Division Duplex) method is used as a duplex communication method. Here, the mobile station #1 is a mobile station determined to be the first mobile station, specifically, the mobile station 200 . The mobile stations #2 and #3 are mobile stations determined to be the second mobile stations, specifically, the mobile stations 200a and 200b. Frames #0 to #n+1 represent frame times based on a certain point of time.

In frame #0, the radio base station 100 transmits information instructing communication quality estimation to the mobile station 200 . Here, the weight vector to be estimated is not limited. Then, the mobile station 200 performs communication quality estimation processing for weight vectors of all codebooks. Then, the mobile station 200 transmits feedback information to the radio base station 100 . As a result, weight vector assignment to the mobile station 200 is determined. In addition, the allocation time is set to n frame times (frames #1 to #n). Also, the allocation time can be adaptively determined according to the communication status such as the communication quality and the moving speed of the mobile station.

In frame #1, the radio base station 100 starts multi-antenna transmission to the mobile station 200 . In addition, the radio base station 100 transmits information instructing communication quality estimation to the mobile stations 200a and 200b. Here, the code of the codebook to which the weight vector assigned to the mobile station 200 belongs is designated. Then, the mobile stations 200a and 200b perform communication quality estimation processing for the weight vectors belonging to the specified codebook. Then, the mobile stations 200a and 200b transmit feedback information to the radio base station 100 . As a result, when simultaneous transmission to the mobile stations 200, 200a, and 200b is possible, weight vector assignment to the mobile stations 200a, 200b is determined.

During the period of frames #2 to #n, the radio base station 100 applies the weight vectors allocated to the mobile stations 200, 200a, and 200b, and performs precoded MIMO communication. The mobile stations 200, 200a, and 200b receive the radio signal output from the radio base station 100, and acquire user data addressed to the mobile station, respectively.

In frame #n, when it continues to be determined that the mobile station 200 is the mobile station with the highest priority, the radio base station 100 transmits control information indicating that the weight vector needs to be updated to the mobile station 200 . Then, the mobile station 200 performs communication quality estimation processing for weight vectors of all codebooks in parallel with acquiring user data. Then, the mobile station 200 transmits feedback information to the radio base station 100 . As a result, the weight vector assignment to the mobile station 200 is updated. In addition, the allocation time is set to n frame times (frames #n+1 to #2n).

In frame #n+1, the radio base station 100 starts multi-antenna transmission to the mobile station 200 again. In addition, the radio base station 100 transmits information instructing communication quality estimation to the mobile stations 200a and 200b. Then, the mobile stations 200a and 200b perform communication quality estimation processing for weight vectors belonging to the codebook specified by the radio base station 100 . Then, the mobile stations 200a and 200b transmit feedback information to the radio base station 100 . As a result, the weight vector assignments to the mobile stations 200a, 200b are updated.

Moreover, when the weight vector does not change before and after updating the allocation of the mobile station 200 and continues to transmit data to the mobile stations 200a and 200b, the allocation of the mobile stations 200a and 200b can also be automatically updated in frame #n+1 , without causing the mobile stations 200a, 200b to perform quality estimation processing.

By using such a mobile communication system, an optimal weight vector can be assigned to the first mobile station with the highest priority. In addition, for other mobile stations, it is possible to limit the object range of the quality estimation process to the weight vectors belonging to the codebook selected by the first mobile station, so that the processing load/circuit scale/power consumption can be significantly reduced. In addition, it is also possible to reduce the amount of feedback information, so that the ratio of radio resources used for feedback information to the entire uplink radio resources is reduced.

In particular, the greater the number of pre-defined codebooks, the more pronounced the above effect. Specifically, when c codebooks with n weight vectors are defined, the first mobile station can select the best weight vector from n×c weight vectors; It is enough to select an appropriate weight vector from among the weight vectors of 1/c times (or less than 1/c times). In addition, in the feedback information from the first mobile station, an amount of information for identifying n×c weight vectors is required. In the feedback information from other mobile stations, it is sufficient if there is an amount of information for respectively identifying n weight vectors.

[the second embodiment]

Next, a second embodiment will be described in detail with reference to the drawings. The description will focus on the differences from the above-mentioned first embodiment, and the description of the same matters will be omitted.

FIG. 10 is a diagram showing the system configuration of the second embodiment. Like the first embodiment, the mobile communication system of the second embodiment is a wireless communication system in which a wireless base station performs wireless communication with a plurality of mobile stations. This radio communication system includes a radio base station 300 and mobile stations 400, 400a, 400b, and 400c.

The functions of the radio base station 300 and the mobile stations 400, 400a, 400b, and 400c are basically the same as those of the radio base station 100 and the mobile stations 200, 200a, 200b, and 200c of the first embodiment. However, the radio base station 300 can form four orthogonal directional beams using four transmitting and receiving antennas. The radio base station 300 adaptively controls beam directivity, and outputs a beam to a desired mobile station. The four transmitting and receiving antennas included in the radio base station 300 are installed so that the spatial correlation between transmission signals is high.

FIG. 11 is a diagram showing functions of a radio base station according to the second embodiment. The radio base station 300 has transmitting and receiving antennas 311, 312, 313, 314, antenna duplexers 321, 322, 323, 324, receiving units 331, 332, 333, 334, demodulating unit 341, channel decoding unit 342, and control information extracting unit 351. , user data extraction unit 352, reception quality estimation unit 353, communication control unit 361, weight generation unit 362, scheduler 363, correction processing unit 364, control information generation unit 371, user data generation unit 372, pilot signal generation unit 373 , a channel coding unit 381 , a modulation unit 382 , a multi-antenna control unit 383 , and transmission units 391 , 392 , 393 , and 394 .

Transceiver antennas 311, 312, 313, 314, antenna duplexers 321, 322, 323, 324, demodulation unit 341, channel decoding unit 342, control information extraction unit 351, user data extraction unit 352, reception quality estimation unit 353, scheduling The functions of the controller 363, the control information generation unit 371, the user data generation unit 372, the pilot signal generation unit 373, the channel coding unit 381, the modulation unit 382, and the multi-antenna control unit 383 are the same as those of the first embodiment shown in FIG. Modules with the same name in the wireless base station 100 are the same.

The reception units 331 , 332 , 333 , and 334 convert the reception signals obtained from the antenna duplexers 321 , 322 , 323 , and 324 into baseband signals, respectively, and output them to the demodulation unit 341 . At this time, the receiving units 331 , 332 , 333 , and 334 perform correction processing on phase differences of received signals generated between the transmitting and receiving antennas 311 , 312 , 313 , and 314 according to an instruction from the correction processing unit 364 .

The communication control unit 361 controls operations in the radio base station 300 based on the control information acquired from the control information extraction unit 351 , the communication quality estimation result acquired from the reception quality estimation unit 353 , and instructions from the scheduler 363 .

For example, the communication control unit 361 determines a communication scheme applicable to the mobile stations 400 , 400 a , 400 b , and 400 c and controls the demodulation unit 341 , channel decoding unit 342 , channel coding unit 381 , and modulation unit 382 . In addition, the communication control unit 361 determines weight vectors assigned to the mobile stations 400, 400a, 400b, and 400c, controls the multi-antenna control unit 383, and controls the weight generation unit 362 to generate weight vectors.

In addition, the communication control unit 361 controls the correction processing unit 364 so as to correct the phase difference of the reception signal generated between the transmission and reception antennas 311 , 312 , 313 , and 314 . In addition, the communication control unit 361 instructs the control information generation unit 371 to transmit control information to the mobile stations 400, 400a, 400b, and 400c as necessary.

The weight generation unit 362 manages weight vectors assigned to the mobile stations 400, 400a, 400b, and 400c. Specifically, the weight generation unit 362 generates a plurality of weight vectors so as to form four orthogonal directional beams under the control of the communication control unit 361 . This weight vector means the weight of the orthogonal multi-beam. Then, the weight generation unit 362 notifies the multi-antenna control unit 383 of the generated weight vector.

The correction processing unit 364 determines the phase difference of signals generated between the transmitting and receiving antennas 311 , 312 , 313 , and 314 under the control of the communication control unit 361 . Then, the correction processing unit 364 instructs the receiving units 331 , 332 , 333 , and 334 and the transmitting units 391 , 392 , 393 , and 394 to perform phase correction.

Transmitters 391 , 392 , 393 , and 394 convert baseband signals acquired from multi-antenna control unit 383 into transmission signals for wireless transmission, and output them to antenna duplexers 321 , 322 , 323 , and 324 , respectively. At this time, the transmitting units 391 , 392 , 393 , and 394 perform correction processing on phase differences of received signals generated between the transmitting and receiving antennas 311 , 312 , 313 , and 314 according to an instruction from the correction processing unit 364 .

FIG. 12 is a diagram illustrating functions of a mobile station according to the second embodiment. The mobile station 400 has a transmitting and receiving antenna 411, a receiving antenna 412, an antenna duplexer 421, receiving units 431 and 432, a demodulation unit 441, a channel decoding unit 442, a control information extraction unit 451, a user data extraction unit 452, and a reception quality estimation unit 453. , feedback information generation unit 454 , communication control unit 461 , control information generation unit 471 , user data generation unit 472 , pilot signal generation unit 473 , channel coding unit 481 , modulation unit 482 and transmission unit 491 . Furthermore, the mobile stations 400a, 400b, and 400c can also be realized with the same module configuration as the mobile station 400 .

Transceiving antenna 411, receiving antenna 412, antenna duplexer 421, receiving units 431, 432, demodulation unit 441, channel decoding unit 442, control information extraction unit 451, user data extraction unit 452, control information generation unit 471, user data generation The functions of the unit 472, the pilot signal generation unit 473, the channel coding unit 481, the modulation unit 482, and the transmission unit 491 are the same as those of the same-named modules in the mobile station 200 of the first embodiment shown in FIG. 4 .

The reception quality estimation unit 453 continuously estimates downlink communication quality based on the demodulated signal obtained from the demodulation unit 441 and the decoded data obtained from the channel decoding unit 442 . Then, the reception quality estimation unit 453 outputs the estimation result to the control information generation unit 471 .

In addition, when the communication control unit 461 instructs to perform estimation processing for assigning weight vectors, the reception quality estimation unit 453 recognizes a predetermined standard signal included in each directional beam output from the radio base station 300, and estimates the communication value based on the reference signal. quality. However, when the communication control unit 461 designates a candidate for a directional beam, the reception quality estimation unit 453 limits the target range to the designated directional beam to estimate the communication quality. Then, the reception quality estimation unit 453 outputs the estimation result to the feedback information generation unit 454 .

The feedback information generation unit 454 determines the optimum one or more directional beams based on the estimation result acquired from the reception quality estimation unit 453 . Then, the feedback information generation unit 454 generates feedback information indicating the determination result, and outputs it to the control information generation unit 471 . Here, in order to specify the optimum directional beam, the feedback information uses a beam number for identifying each directional beam.

The communication control unit 461 controls the operation of the mobile station 400 based on the control information acquired from the control information extraction unit 451 . For example, the communication control unit 461 determines the communication method used by the radio base station 300 based on the control information, and controls the demodulation unit 441 and the channel decoding unit 442 . Also, when acquiring control information indicating a feedback information request for assigning weight vectors, the communication control unit 461 instructs the reception quality estimation unit 453 to perform estimation processing. Here, when the feedback information request includes a beam number, it indicates that the estimation process is limited to the directional beam of the beam number. In addition, the communication control unit 461 instructs the control information generation unit 471 to transmit control information to the radio base station 300 as necessary.

Fig. 13 is a diagram showing an example of communication between a radio base station and a mobile station according to the second embodiment. This example is a case where a time division duplex method is used as a duplex communication method. Here, the mobile station #1 is a mobile station determined to be the first mobile station, specifically, the mobile station 400 . Mobile stations #2 and #3 are mobile stations determined to be the second mobile stations, specifically, mobile stations 400a and 400b. In addition, frames #0 to #n+1 represent frame times based on a certain point of time.

In frame #0, the radio base station 300 transmits information instructing communication quality estimation to the mobile station 400 . Here, the directional beam to be estimated is not limited. In addition, the radio base station 300 outputs reference signals for each of the four directional beams (beams #1 to #4). Then, mobile station 400 performs communication quality estimation processing based on the reference signal for all directional beams. Then, the mobile station 400 transmits feedback information to the radio base station 300 . As a result, weight vector assignment to mobile station 400 is determined. In addition, the allocation time is set to n frame times (frames #1 to #n). In addition, the allocation time may be adaptively determined according to communication conditions such as the beam width of the directional beam and the moving speed of the mobile station.

In frame #1, the radio base station 300 starts orthogonal multi-beam transmission to the mobile station 400 . In addition, the radio base station 300 transmits information instructing to perform communication quality estimation to the mobile stations 400a and 400b. Here, numbers of directional beams (beams #1, #2, #4) other than the directional beams corresponding to the weight vector assigned to the mobile station 400 are designated. In addition, the radio base station 300 outputs a reference signal for each designated directional beam. Then, the mobile stations 400a and 400b perform communication quality estimation processing for the designated directional beam. Then, the mobile stations 400a and 400b transmit feedback information to the radio base station 300 . In the example of FIG. 13 , it is assumed that simultaneous transmission to mobile stations 400 and 400a is possible, and weight vector assignment to mobile station 400a is determined.

In frame #2, the radio base station 300 starts orthogonal multi-beam transmission to the mobile station 400a. In addition, the radio base station 300 transmits information instructing again to perform communication quality estimation to the mobile station 400b whose assignment has not been determined. Here, numbers of directional beams (beams #2, #4) other than the directional beams corresponding to the weight vectors assigned to the mobile stations 400, 400a are designated. In addition, the radio base station 300 outputs a reference signal for each designated directional beam. Then, the mobile station 400b performs communication quality estimation processing for the designated directional beam. Then, the mobile station 400b transmits feedback information to the radio base station 300 . As a result, the weight vector assignment to the mobile station 400b is determined.

During the period of frames #3 to #n, the radio base station 300 applies the weight vectors assigned to the mobile stations 400, 400a, and 400b, and performs space division multiplexing (SDM: Space Division Multiplexing) transmission by orthogonal multibeams. The mobile stations 400, 400a, and 400b receive the radio signal output from the radio base station 300, and acquire user data addressed to the mobile station, respectively.

In frame #n, when it continues to be determined that the mobile station 400 is the mobile station with the highest priority, the radio base station 300 transmits control information indicating that the weight vector needs to be updated to the mobile station 400 . In addition, the radio base station 300 outputs reference signals for each of the beams #1 to #4. Then, mobile station 400 performs communication quality estimation processing based on the reference signal for all directional beams. Then, the mobile station 400 transmits feedback information to the radio base station 300 . As a result, the weight vector assignment to the mobile station 400 is updated. In addition, the allocation time is set to n frame times (frames #n+1 to #2n).

In frame #n+1, the radio base station 300 starts orthogonal multi-beam transmission to the mobile station 400 again. Also, the radio base station 300 transmits information instructing communication quality estimation to the mobile stations 400a, 400b, and outputs reference signals for beams #1, #2, #4, respectively. Then, the mobile stations 400a and 400b perform communication quality estimation processing for the directional beam specified by the radio base station 300 . Then, the mobile stations 400a and 400b transmit feedback information to the radio base station 300 . As a result, the weight vector assignments to the mobile stations 400a, 400b are updated.

Moreover, when the weight vector does not change before and after updating the allocation of the mobile station 400 and continues to send data to the mobile stations 400a and 400b, the allocation of the mobile stations 400a and 400b can also be automatically updated in frame #n+1 , without causing the mobile stations 400a, 400b to perform quality estimation processing.

By using such a mobile communication system, it is possible to allocate weight vectors so as to form optimal directional beams to the first mobile station with the highest priority. In addition, for other mobile stations, it is possible to limit the target range of the quality estimation process to a directional beam different from the beam selected by the first mobile station, thereby significantly reducing processing load, circuit size, and power consumption. In addition, it is possible to limit the number of directional beams for transmitting reference signals, thereby reducing the ratio of radio resources used for reference signals to the entire downlink radio resources. In addition, it is also possible to reduce the amount of feedback information, so that the ratio of radio resources used for feedback information to the entire uplink radio resources is reduced.

Furthermore, in the present embodiments (the first embodiment and the second embodiment), a cellular mobile communication system has been described, but it can also be applied to other types of wireless communication systems. In addition, the multi-antenna transmission control described in this embodiment may be executed by radio communication terminals other than the radio base station. In addition, in the present embodiment, the multi-antenna transmission of the multi-antenna MIMO method and the beamforming method has been described, but it can also be applied to other transmission methods.

In addition, the antenna configuration described in this embodiment can be appropriately changed according to the wireless transmission path, the installation environment of the communication device, and the like. In addition, part or all of the communication control function and scheduling function of the radio base station according to this embodiment may be installed in a radio control device other than the radio base station.

In addition, in this embodiment, any modulation method and coding method can be used. In addition, frequency division multiplexing (FDM: Frequency Division Multiplexing)/time division multiplexing (TDM: Time Division Multiplexing)/code division multiplexing (CDM: Code Division Multiplexing)/Orthogonal Frequency Division Multiplexing (OFDM: Orthogonal Frequency Division Multiplexing) and other arbitrary multiplexing methods. Here, in the case of using CDM, modules for performing spread spectrum processing and despreading processing, etc. can be appropriately set, and in the case of using OFDM, modules for performing Fast Fourier Transform (FFT: Fast Fourier Transform) and Fast Fourier Transform can be appropriately set. Modules such as leaf inverse transform (IFFT: InverseFast Fourier Transform).

The foregoing merely illustrates the principles of the invention. Moreover, for those skilled in the art, various modifications and changes can be made. The present invention is not limited to the exact structures and application examples shown and described above, and all corresponding modifications and equivalents can be regarded as defined by the appended claims and Their equivalents define the scope of the present invention.

Claims (3)

1. a kind of reception device, it is characterised in that the reception device has：

Acceptance division, it receives the information related to weight vectors sent from dispensing device；

Control unit, its in the information related to weight vectors the candidate without weight vectors specify in the case of, from Optimal weight vectors are selected in whole weight vectors, in the candidate of the information right of possession weight vector related to weight vectors Specify in the case of, from being designated as selecting suitable weight vectors in the weight vectors of the candidate；And

Sending part, it sends the weight vectors selected by the control unit to the dispensing device,

The appointed candidate is belonging in multiple code books and the weight vectors identical code book for distributing to other reception devices Weight vectors, be the weight vectors that can concurrently use with the weight vectors for distributing to other reception devices, it is described Other reception devices are selected from multiple reception devices according to the relative importance value or communication quality of grouped data by dispensing device Reception device.

2. reception device according to claim 1, it is characterised in that

In the information related to weight vectors the candidate without weight vectors specify in the case of, according to communication quality Estimated result select weight vectors from whole weight vectors,

In the case of the specifying of candidate of related to the weight vectors information right of possession weight vector, according to communication quality Estimated result is from being designated as selecting weight vectors in the weight vectors of the candidate.

3. reception device according to claim 1, it is characterised in that

The information related to weight vectors is received by acceptance division as control signal.