WO2018168630A1

WO2018168630A1 - Wireless base station

Info

Publication number: WO2018168630A1
Application number: PCT/JP2018/008937
Authority: WO
Inventors: 匡史岩渕; アナスベンジャブール; 祥久岸山
Original assignee: 株式会社Ｎｔｔドコモ
Priority date: 2017-03-17
Filing date: 2018-03-08
Publication date: 2018-09-20

Abstract

The purpose of this invention is to improve the estimation accuracy of the direction of a terminal without increasing the number of beam candidates. In a wireless base station (10), a beam selection unit (153) selects, as a transmission beam used in data transmission, the beam candidate having the highest reception quality. A feedback signal processing unit (152) acquires RSS of PRS transmitted from a user terminal, using each of a plurality of positioning beams which include transmission beams. A positioning unit (154) estimates, as the direction of a user terminal, the direction obtained by correcting the direction of the center of a transmission beam using the RSS of each of the measurement beams.

Description

Wireless base station

The present invention relates to a radio base station.

In the UMTS (Universal Mobile Telecommunication System) network, Long Term Evolution (LTE) has been specified for the purpose of higher data rates and low delay. In addition, a successor system of LTE is also being studied for the purpose of further widening the bandwidth and speeding up from LTE. LTE successors include LTE-A (LTE-Advanced), FRA (Future Radio Access), 5G (5th generation mobile mobile communication system), 5G + (5G plus), New-RAT (Radio Access Technology), etc. There is what is called.

In future wireless communication systems (for example, 5G), a large number of antenna elements (for example, 100 elements or more) are used in a high frequency band (for example, 5 GHz or more) in order to further increase the speed of signal transmission and reduce interference. It has been studied to perform BF (beam forming) using a massive MIMO (Multiple Input Input Multiple Output) technique.

In a radio base station (hereinafter simply referred to as “base station”), a beam formed by Massive MIMO technology is directed in the direction in which the reception quality at the user terminal (hereinafter simply referred to as “terminal”) is highest.

In recent years, services using terminal location information have attracted attention as applications using wireless technology. Therefore, in the future, a technology capable of positioning with higher accuracy than at present is required.

As a positioning method for a device such as a terminal, a method using a positioning signal from a GNSS (Global Navigation Satellite System) satellite (not shown) is known (for example, see Patent Document 1). GNSS is a general term for satellite navigation systems having performance (accuracy and reliability) that can be used for civil aeronautical navigation such as GPS (Global Positioning System), GLONASS, and Galileo.

Since the beam formed by the Massive MIMO technology is directed in the direction in which the terminal exists, the direction in which the terminal exists can be estimated in the beam control process of the Massive MIMO technology. Furthermore, since the narrower beam can be formed using a large number of antenna elements as the frequency becomes higher, the estimation accuracy is improved. Therefore, the affinity between MassiveMa MIMO technology and terminal positioning is considered high.

Conventionally, the beam having the highest received power is selected from the beam candidates of the base station, and the center direction of the selected beam is estimated as the direction of the terminal (azimuth / elevation angle) with respect to the base station.

JP-A-8-65413

However, in the conventional terminal direction estimation method, when the terminal exists between the center direction of the selected beam and the center direction of the beam adjacent to the selected beam, the estimation accuracy is lowered. If the beam width is narrowed, the estimation accuracy can be improved, but the number of beam candidates increases, so the overhead for beam search increases.

One embodiment of the present invention provides a new configuration that can improve the estimation accuracy of the terminal direction without increasing the number of beam candidates.

A radio base station according to an aspect of the present invention is a radio base station that communicates with a user terminal using beam transmission and beam reception, and uses a beam having the highest reception quality among beam candidates for data transmission. A beam selection unit that selects as a transmission beam, and a parameter acquisition unit that acquires a parameter related to the reception quality of a signal transmitted using each of the positioning beams including a plurality of beams including the transmission beam; And a positioning unit that estimates the direction of the user terminal using the parameters of each positioning beam.

According to one aspect of the present invention, there is provided a new configuration that can improve the estimation accuracy of the terminal direction without increasing the number of beam candidates.

3 is a block diagram illustrating a configuration example of a base station according to Embodiment 1. FIG. 3 is a block diagram illustrating a configuration example of a terminal according to Embodiment 1. FIG. 6 is a sequence diagram showing operations of a base station and a terminal according to Embodiment 1. FIG. It is a figure which shows an example of the propagation path condition between the base station which concerns on Embodiment 1, and a terminal. 6 is a sequence diagram showing operations of a base station and a terminal according to Embodiment 2. FIG. It is a figure which shows an example of the propagation path condition between the base station which concerns on Embodiment 2, and a terminal. It is a figure which shows an example of the hardware constitutions of the base station and terminal which concern on this invention.

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

In this embodiment, RSS (Received Signal Strength) is used as a parameter used for estimating the terminal direction. Parameters that can be used for estimation of other terminal directions include, for example, RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), RSSI (Received Signal Strength Indicator), path loss (propagation loss), SINR (Signal Loss). to Interference plus Noise Ratio).

Further, in this embodiment, TOA (Time Of Arrival) is used as a parameter used for estimating the distance from the base station to the terminal. The arrival time is the time from the signal transmission time of the base station to the signal reception time of the terminal. In addition, TDOA (Time | difference | of | Arrival) etc. are mentioned as a parameter which can be used for estimation of another terminal distance. Moreover, RSS can also be used for terminal distance estimation.

[Embodiment 1]
The radio communication system according to Embodiment 1 includes at least base station 10 shown in FIG. 1 and terminal 20 shown in FIG. The terminal 20 is connected to the base station 10. The base station 10 transmits a DL (Down Link) signal to the terminal 20. The DL signal includes, for example, a DL data signal (eg, PDSCH (Physical Downlink Shared Channel)) and a DL control signal (eg, PDCCH (Physical Downlink Control Channel)) for demodulating and decoding the DL data signal. It is.

In the first embodiment, the base station 10 performs BF and estimates the direction of the terminal 20 relative to the base station 10 based on the RSS in the terminal 20 of the signal transmitted from each positioning beam of the base station 10. explain.

<Base station configuration>
FIG. 1 is a diagram illustrating a configuration example of a base station 10 according to the present embodiment. 1 includes a discovery signal generation unit 101, a beam number determination unit 102, a PRS generation unit 103, a data signal generation unit 104, a precoding unit 105, a weight selection unit 106, a transmission beam A forming unit 107, a communication unit 108, an antenna 109, a reception beam forming unit 151, a feedback signal processing unit 152, a beam selection unit 153, a positioning unit 154, a post coding unit 155, and a data signal processing unit 156 And the structure including is taken.

In FIG. 1, a configuration unit for transmitting / receiving an OFDM (Orthogonal Frequency Division Multiplexing) signal in the base station 10 (for example, an IFFT (Inverse Fast Fourier Transform) processing unit, a CP (Cyclic Prefix) addition unit, a CP removal unit) , FFT (Fast Fourier Transform) processing unit) and the like are omitted.

The discovery signal generation unit 101 generates the same number of discovery signals as the number M (M is a plurality) of BF weight candidates. The discovery signal is a reference signal used to determine a beam (BF weight). Discovery signal generation section 101 outputs the generated discovery signal to transmission beamforming section 107.

The beam number determination unit 102 determines k as a basis of the number of positioning beams (2k + 1) used in the positioning process (k is a natural number). The beam number determination unit 102 notifies the PRS generation unit 103 and the weight selection unit 106 of the determined number of positioning beams (2k + 1). A specific example of the criterion for determining k will be described later.

The PRS generation unit 103 generates (2k + 1) PRSs based on the notification from the beam number determination unit 102. PRS is a reference signal used for positioning. The PRS generation unit 103 outputs the generated PRS to the transmission beamforming unit 107.

The data signal generation unit 104 performs encoding processing and modulation processing on L (L is an integer equal to or less than M) stream data for the terminal 20, and generates a data signal (downlink signal). The data signal generation unit 104 outputs the generated data signal to the precoding unit 105. 1 shows only the data signal generation unit 104 for one terminal 20 (i-th terminal 20), the base station 10 has a data signal generation unit 104 for each of a plurality of terminals 20. Shall.

The precoding unit 105 multiplies the L data signals output from the data signal generation unit 104 by a precoding matrix for each subcarrier to generate M data signals after precoding. Precoding section 105 outputs the generated M data signals to transmission beamforming section 107.

The weight selection unit 106 selects a BF weight that forms a transmission beam (index #m (m is an integer from 1 to M, see FIG. 4)) selected by the beam selection unit 153 during data transmission. Then, the data is output to the transmission beam forming unit 107 and the reception beam forming unit 151.

In addition, the weight selection unit 106 determines the index from (# m−k) to (#) around the transmission beam #m selected by the beam selection unit 153 based on the notification from the beam number determination unit 102 during positioning. Each BF weight forming each of the plurality of positioning beams up to m + k) is selected and output to the transmission beam forming unit 107 and the reception beam forming unit 151.

The transmission beamforming unit 107 multiplies the discovery signal output from the discovery signal generation unit 101 by a BF weight candidate before starting data transmission. Transmit beamforming section 107 outputs a discovery signal after multiplication by BF weight candidates to communication section 108.

Also, the transmission beamforming unit 107 multiplies the data signal output from the precoding unit 105 by the BF weight output from the weight selection unit 106 during data transmission. Transmit beamforming section 107 outputs the data signal multiplied by the BF weight to communication section 108.

Also, the transmission beamforming unit 107 multiplies each BF weight selected by the weight selection unit 106 by the PRS output from the PRS generation unit 103 during positioning. Transmit beamforming section 107 outputs the PRS after multiplying each BF weight to communication section 108.

Communication units 108-1 to 108-M are provided corresponding to M antennas 109 (antenna elements), respectively. Each communication unit 108 performs transmission processing such as D / A conversion and up-conversion on the signal output from the transmission beamforming unit 107 to generate a radio frequency transmission signal. Each communication unit 108 transmits the generated radio frequency transmission signal to the terminal 20 from each of the M antennas 109. Note that M beam candidates are formed by transmitting a signal obtained by multiplying each of the BF weight candidates from the M antennas 109 (see FIG. 4).

Further, each communication unit 108 performs reception processing such as down-conversion and A / D conversion on the signal transmitted from the terminal 20 and received by each of the M antennas 109. Each communication unit 108 outputs a data signal and a feedback signal obtained by performing the reception process to the reception beam forming unit 151.

The reception beamforming unit 151 multiplies the feedback signal output from each communication unit 108 by a BF weight candidate before starting data reception. Reception beamforming section 151 outputs the feedback signal after being multiplied by the BF weight candidate to feedback signal processing section 152.

Also, the reception beamforming unit 151 multiplies the data signal output from each communication unit 108 by the BF weight output from the weight selection unit 106 at the time of data reception. Reception beamforming section 151 outputs the data signal after being multiplied by the BF weight to postcoding section 155.

Also, the reception beamforming unit 151 multiplies the data signal output from each communication unit 108 by the BF weight output from the weight selection unit 106 during positioning. Reception beamforming section 151 outputs the feedback signal after multiplication by the BF weight to feedback signal processing section 152.

The feedback signal processing unit 152 performs demodulation processing and decoding processing on the feedback signal output from the reception beam forming unit 151, and the RSS of the discovery signal in each beam candidate measured by the terminal 20 and for each positioning Extract RSS and TOA of PRS in the beam. The feedback signal processing unit 152 outputs the RSS of the discovery signal in each extracted beam candidate to the beam selection unit 153. Further, the feedback signal processing unit 152 outputs the RSS and TOA of the PRS in each extracted positioning beam to the positioning unit 154.

The beam selection unit 153 selects a transmission beam based on the RSS of the discovery signal in each beam candidate. Specifically, the beam selection unit 153 selects the beam having the highest RSS as the transmission beam. The beam selection unit 153 outputs the index #m of the selected transmission beam to the weight selection unit 106.

The positioning unit 154 outputs the RSS and TOA of the PRS in each positioning beam measured by the terminal 20 and the RSS and TOA of the feedback signal from the terminal 20 received in each positioning beam output from the feedback signal processing unit 152. And the positioning (position estimation) of the terminal 20 is performed based on the beam angle of each positioning beam. A specific example of the positioning method in the positioning unit 154 will be described later.

The post-coding unit 155 performs post-coding on the data signal output from the reception beamforming unit 151 using the post-coding matrix. The post coding unit 155 outputs the post-coded data signal to the data signal processing unit 156.

The data signal processing unit 156 performs demodulation processing and decoding processing on the data signal output from the post-coding unit 155 to obtain L stream data from the i-th terminal 20.

<Terminal configuration>
FIG. 2 is a block diagram illustrating a configuration example of the terminal 20 according to the first embodiment. 2 includes an antenna 201, a communication unit 202, a reception quality measurement unit 203, an arrival time calculation unit 204, a post coding unit 205, a data signal processing unit 206, a feedback signal generation unit 251, The data signal generation unit 252 and the precoding unit 253 are included.

Note that FIG. 2 shows the configuration of the i-th terminal 20 as an example. In FIG. 2, description of components (for example, IFFT processing unit, CP adding unit, CP removing unit, FFT processing unit) for transmitting / receiving the OFDM signal in the terminal 20 is omitted.

Communication units 202-1 to 202-N are provided corresponding to N antennas 201 (N is an integer of 2 or more), respectively. Each communication unit 202 performs reception processing such as down-conversion and A / D conversion on the reception signal received via the antenna 201. Each communication unit 202 outputs the discovery signal obtained by performing the reception process to the reception quality measurement unit 203, and outputs the PRS obtained by performing the reception process to the reception quality measurement unit 203 and the arrival time calculation unit 204. The data signal is output to the post coding unit 205.

In addition, each communication unit 202 performs transmission processing such as D / A conversion and up-conversion on the feedback signal output from the feedback signal generation unit 251 or the data signal output from the precoding unit 253 to perform radio frequency transmission. The transmission signal is generated. Each communication unit 202 transmits the generated radio frequency transmission signal from each of the N antennas 201 to the base station 10.

The reception quality measurement unit 203 uses the discovery signal output from the communication unit 202 to measure the RSS of each of M beam candidates. Also, the reception quality measurement unit 203 uses the PRS output from the communication unit 202 to measure RSS of each (2k + 1) positioning beams. The reception quality measurement unit 203 outputs the RSS of the discovery signal in each measured beam candidate and the RSS of the PRS in each positioning beam to the feedback signal generation unit 251.

The arrival time calculation unit 204 calculates the TOA of each (2k + 1) positioning beams using the PRS output from the communication unit 202. The arrival time calculation unit 204 outputs the calculated PRS TOA for each positioning beam to the feedback signal generation unit 251.

The post coding unit 205 performs post coding on the data signal output from the communication unit 202 using the post coding matrix, and outputs the post-coded data signal to the data signal processing unit 206.

The data signal processing unit 206 performs demodulation processing and decoding processing on the data signal output from the post coding unit 205 to obtain L stream data for the i-th terminal 20.

The feedback signal generation unit 251 performs an encoding process and a modulation process on the RSS output from the reception quality measurement unit 203 and the TOA and TDOA output from the arrival time calculation unit 204 to generate a feedback signal. The feedback signal generation unit 251 outputs the generated feedback signal to the communication unit 202.

The data signal generation unit 252 performs encoding processing and modulation processing on L (L is an integer equal to or less than M) stream data for the base station 10 to generate a data signal (uplink signal). The data signal generation unit 104 outputs the generated data signal to the precoding unit 253.

The precoding unit 253 multiplies the L data signals output from the data signal generation unit 252 by a precoding matrix for each subcarrier to generate M data signals after precoding. The precoding unit 253 outputs the generated M data signals to the communication unit 202.

<Specific example of k determination method>
Next, a specific example of a method for determining k will be described.

The number-of-beams determination unit 102 adaptively depends on the situation of the base station 10 (geographic relationship between the base station 10 and the terminal 20, the moving speed of the terminal 20, the beam width, etc., which the base station 10 grasps or estimates) k can be determined. For example, the beam number determination unit 102 determines k according to the distance between the base station 10 and the terminal 20 so that k decreases as the distance decreases. Note that the base station 10 can estimate the distance between the base station 10 and the terminal 20 based on the feedback from the terminal 20 or the received power of the signal received by the base station 10.

Also, the beam number determination unit 102 determines k according to the moving speed of the terminal 20 so that k decreases as the moving speed decreases. In addition, the base station 10 can estimate the moving speed of the terminal 20 from the feedback from the terminal 20 or the past position estimation result.

The beam number determination unit 102 determines k according to the beam width of the base station 10 so that k becomes smaller as the beam width becomes wider.

<Specific example of positioning method>
Next, a specific example of the positioning method of the present embodiment will be described. In the following example, k = 1 is set for simplicity of explanation.

First, a method for estimating the direction of the terminal 20 by the positioning unit 154 will be described.

First, the positioning unit 154 calculates the ratio of the RSS of the beam (beam # m−1 and beam # m + 1) adjacent to the transmission beam #m (the beam having the highest RSS).

Next, the positioning unit 154 calculates a correction angle based on the RSS ratio. If the angle between the center direction of the beam #m and the center direction of the beam # m−1 is −Δθ, and the angle between the center direction of the beam #m and the center direction of the beam # m + 1 is + Δθ, the beam # m−1 the ratio of _{P m + 1} is the RSS of _{P m-1} and the beam # m + 1 is the RSS _{_{is, P m-1: P m}} + 1 = p: for q, the positioning unit 154, using the following equation (1) Thus, the correction angle θc is calculated.
θc = (− p + q) × Δθ / (p + q) (1)

Then, the positioning unit 154 sets the direction of the terminal 20 to a value obtained by adding the correction angle θc to the center direction angle θm of the beam #m.

For example, when P _m−1 : P _{m + 1} = 2: 1, θc = −Δθ / 3. In this case, the positioning unit 154 estimates the direction of the terminal 20 as an angle of θm−Δθ / 3.

Next, a method for estimating the distance of the terminal 20 by the positioning unit 154 will be described.

The positioning unit 154 calculates the distance d between the base station 10 and the terminal 20 by multiplying the arrival time _TTOA by the speed of light c. Alternatively, the positioning unit 154 may back-calculate the distance d from the propagation loss equation.

Thus, the base station 10 can estimate the position of the terminal 20 by estimating the direction and distance of the terminal 20.

Note that the above is an example of the positioning method, and in the present embodiment, there is no limitation on the calculation method and the positioning method of the correction angle θc. For example, the positioning unit 154 may estimate the position where the received power is closest in the corrected direction as the position of the terminal 20 using the received power map prepared in advance.

<Operation of base station and terminal>
Next, operations of base station 10 and terminal 20 of the present embodiment will be described in detail with reference to FIGS. FIG. 3 is a sequence diagram showing operations of base station 10 and terminal 20 according to the present embodiment. Moreover, FIG. 4 is a figure which shows an example of the propagation path condition between the base station 10 and the terminal 20 which concerns on this Embodiment. FIG. 4 shows a case where k = 2.

First, the base station 10 transmits a discovery signal to the terminal 20 (ST101). Each discovery signal is multiplied by a BF weight candidate. In addition, the discovery signal transmitted for each beam candidate (BF weight candidate) is not precoded and is transmitted toward all the antennas 201 of the terminal 20.

Next, the terminal 20 measures the RSS of each beam candidate using the discovery signal (ST102). Then, terminal 20 transmits a feedback signal including RSS of each beam candidate to base station 10 (ST103).

Next, the base station 10 selects a transmission beam based on the RSS of each beam candidate (ST104). Furthermore, the base station 10 determines a transmission beam and a beam around the transmission beam as positioning beams (ST105). In the example of FIG. 4, since the discovery signal transmitted with the beam #m has the highest RSS, the base station 10 selects the beam #m as a transmission beam. Also, the base station 10 determines beam # m−2, beam # m−1, beam #m, beam # m + 1, and beam # m + 2 as positioning beams. As a result, the beam around the beam #m closest to the direction in which the terminal 20 exists is used for positioning.

Next, base station 10 transmits a PRS to terminal 20 using a positioning beam (ST106). The PRS is not precoded and is transmitted toward all the antennas 201 of the terminal 20.

Next, the terminal 20 measures the RSS of each positioning beam using the PRS transmitted by the positioning beam (ST107) and calculates the TOA (ST108). Then, terminal 20 transmits a feedback signal including RSS and TOA of each positioning beam to base station 10 (ST109).

Next, the base station 10 estimates the direction of the terminal 20 based on the RSS of the PRS in each positioning beam, and performs a positioning process (position estimation) for estimating the distance to the terminal 20 based on the TOA (ST110). .

In the present embodiment, the positioning process may be performed in the terminal 20 without performing the feedback of ST109. In addition, a plurality of base stations 10 may perform positioning processing using a plurality of information acquired by feedback signals from the terminals 20.

<Effects of the present embodiment>
Thus, in the present embodiment, the beam having the highest reception quality at the terminal 20 is selected as a transmission beam, and the transmission beam and a plurality of beams around the transmission beam are determined as positioning beams. Based on the RSS in the PRS terminal 20 transmitted and transmitted using each of the positioning beams, the direction in which the center direction of the transmission beam is corrected is estimated as the direction of the terminal 20.

As a result, even when the terminal 20 exists between the center direction of the transmission beam and the center direction of the beam adjacent to the transmission beam, the direction of the terminal 20 can be estimated with high accuracy. Therefore, according to the present embodiment, it is possible to improve the estimation accuracy of the terminal direction without increasing the number of beam candidates.

In this embodiment, the case where PRS is used as a positioning reference signal has been described. However, the present invention is not limited to this, and a signal other than PRS may be used as a positioning reference signal.

The first embodiment has been described above.

[Embodiment 2]
In the second embodiment, the base station 10 performs BF and estimates the direction of the terminal 20 relative to the base station 10 based on the RSS in each positioning beam of the base station 10 of the signal transmitted from the terminal 20. explain.

Note that the configuration example of the base station 10 of the second embodiment is the same as that shown in FIG. The configuration example of the terminal 20 of the second embodiment is the same as that shown in FIG. However, in the second embodiment, PRS transmission / reception is not required.

<Operation of base station and terminal>
Next, operations of the base station 10 and the terminal 20 according to the present embodiment will be described in detail with reference to FIGS. FIG. 5 is a sequence diagram showing operations of base station 10 and terminal 20 according to the present embodiment. Moreover, FIG. 6 is a figure which shows an example of the propagation path condition between the base station 10 and the terminal 20 which concerns on this Embodiment. FIG. 6 shows a case where k = 2.

In FIG. 5, the same steps as those in FIG. 3 are denoted by the same reference numerals as those in FIG.

After determining the positioning beam (ST105), the base station 10 receives the UL (uplink) signal from the terminal 20 using the positioning beam (ST201). Here, as the UL signal, an SRS (Sounding Reference Signal) or a signal transmitted from the other terminal 20 to the base station 10 is used.

The base station 10 measures the RSS of each positioning beam using the UL signal received using the positioning beam (ST202), and calculates the TOA (ST203).

Then, a positioning process (position estimation) is performed in which the direction of the terminal 20 is estimated based on the RSS of the UL signal in each positioning beam, and the distance to the terminal 20 is estimated based on the TOA (ST204). A plurality of base stations 10 may perform the positioning process using the acquired plurality of information.

<Effects of the present embodiment>
Thus, in the present embodiment, the beam having the highest reception quality at the terminal 20 is selected as a transmission beam, and the transmission beam and a plurality of beams around the transmission beam are determined as positioning beams. Then, the direction in which the center direction of the transmission beam is corrected is estimated as the direction of the terminal 20 based on the RSS of the UL signal received using each of the positioning beams.

The embodiment 2 has been described above.

In each of the above embodiments, the case where RSS is used as a parameter used for estimating the terminal direction has been described. However, the present invention is not limited to this, and other parameters such as RSRP, RSRQ, RSSI, path loss, SINR, and the like are used. It may be used. In the present invention, the terminal direction may be estimated using a plurality of these parameters.

In each embodiment, the case where TOA is used as a parameter used for estimating the terminal distance has been described. However, the present invention is not limited to this, and other parameters such as TDOA and RSS may be used. In the present invention, the terminal direction may be estimated using a plurality of these parameters.

Further, in each embodiment, when positioning is performed on the base station 10 side, each of the plurality of base stations 10 may estimate the direction of the terminal 20 by the AOD corresponding to the positioning beam. Thereby, the positioning of the terminal 20 can be performed with high accuracy.

(Hardware configuration)
In addition, the block diagram used for description of the said embodiment has shown the block of the functional unit. These functional blocks (components) are realized by any combination of hardware and / or software. Further, the means for realizing each functional block is not particularly limited. That is, each functional block may be realized by one device physically and / or logically coupled, and two or more devices physically and / or logically separated may be directly and / or indirectly. (For example, wired and / or wireless) and may be realized by these plural devices.

For example, a wireless base station, a user terminal, etc. in an embodiment of the present invention may function as a computer that performs processing of the wireless communication method of the present invention. FIG. 7 is a diagram illustrating an example of a hardware configuration of a radio base station and a user terminal according to an embodiment of the present invention. The base station 10 and the terminal 20 described above may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

In the following description, the term “apparatus” can be read as a circuit, a device, a unit, or the like. The hardware configuration of the base station 10 and the terminal 20 may be configured to include one or a plurality of devices illustrated in the figure, or may be configured not to include some devices.

For example, although only one processor 1001 is shown, there may be a plurality of processors. Further, the processing may be executed by one processor, or the processing may be executed by one or more processors simultaneously, sequentially, or in another manner. Note that the processor 1001 may be implemented by one or more chips.

Each function in the base station 10 and the terminal 20 is obtained by reading predetermined software (program) on hardware such as the processor 1001 and the memory 1002, so that the processor 1001 performs computation and communication by the communication device 1004 or memory This is realized by controlling data reading and / or writing in the storage 1003 and the storage 1003.

The processor 1001 controls the entire computer by operating an operating system, for example. The processor 1001 may be configured by a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic device, a register, and the like. For example, the discovery signal generation unit 101, the beam number determination unit 102, the PRS generation unit 103, the data signal

generation units

104 and 252, the

precoding units

105 and 253, the weight selection unit 106, the transmission beam forming unit 107, and the reception beam forming described above. 151, feedback signal processing section 152, beam selection section 153, positioning section 154, post coding sections 155 and 205, data signal

processing sections

156 and 206, reception quality measurement section 203, arrival time calculation section 204, feedback signal generation section 251 Etc. may be realized by the processor 1001.

Further, the processor 1001 reads a program (program code), software module, or data from the storage 1003 and / or the communication device 1004 to the memory 1002, and executes various processes according to these. As the program, a program that causes a computer to execute at least a part of the operations described in the above embodiments is used. For example, the control unit 101 of the base station 10 may be realized by a control program stored in the memory 1002 and operated by the processor 1001, and may be realized similarly for other functional blocks. Although the above-described various processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. Note that the program may be transmitted from a network via a telecommunication line.

The memory 1002 is a computer-readable recording medium and includes at least one of ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), and the like. May be. The memory 1002 may be called a register, a cache, a main memory (main storage device), or the like. The memory 1002 can store a program (program code), a software module, and the like that can be executed to implement the wireless communication method according to the embodiment of the present invention.

The storage 1003 is a computer-readable recording medium such as an optical disc such as a CD-ROM (Compact Disc ROM), a hard disc drive, a flexible disc, a magneto-optical disc (eg, a compact disc, a digital versatile disc, a Blu-ray). (Registered trademark) disk, smart card, flash memory (for example, card, stick, key drive), floppy (registered trademark) disk, magnetic strip, and the like. The storage 1003 may be referred to as an auxiliary storage device. Further, the above-described storage medium may be, for example, a database including the memory 1002 and / or the storage 1003, a server, or other suitable medium.

The communication device 1004 is hardware (transmission / reception device) for performing communication between computers via a wired and / or wireless network, and is also referred to as a network device, a network controller, a network card, a communication module, or the like. For example, the

communication units

108 and 202 and the

antennas

109 and 201 described above may be realized by the communication device 1004.

The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts an input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that performs output to the outside. The input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

Also, each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured with a single bus or may be configured with different buses between apparatuses.

The base station 10 and the terminal 20 include hardware such as a microprocessor, digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic device (PLD), and field programmable gate array (FPGA). And a part or all of each functional block may be realized by the hardware. For example, the processor 1001 may be implemented by at least one of these hardware.

(Information notification, signaling)
The notification of information is not limited to the aspect / embodiment described in the present specification, and may be performed by other methods. For example, information notification includes physical layer signaling (for example, DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (for example, RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling), It may be implemented by broadcast information (MIB (Master Information Block), SIB (System Information Block))), other signals, or a combination thereof. The RRC signaling may be referred to as an RRC message, and may be, for example, an RRC connection setup message, an RRC connection reconfiguration message, or the like.

(Adaptive system)
Each aspect / embodiment described herein includes LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G, 5G, FRA (Future Radio Access), W-CDMA. (Registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, UWB (Ultra-WideBand), The present invention may be applied to a Bluetooth (registered trademark), a system using another appropriate system, and / or a next generation system extended based on the system.

(Processing procedure etc.)
As long as there is no contradiction, the order of the processing procedures, sequences, flowcharts, and the like of each aspect / embodiment described in this specification may be changed. For example, the methods described herein present the elements of the various steps in an exemplary order and are not limited to the specific order presented.

(Operation of base station)
The specific operation assumed to be performed by the base station (radio base station) in this specification may be performed by the upper node in some cases. In a network composed of one or more network nodes having a base station, various operations performed for communication with a terminal may be performed by the base station and / or other network nodes other than the base station (e.g., It is obvious that this can be performed by MME (Mobility Management Entity) or S-GW (Serving Gateway). In the above, the case where there is one network node other than the base station is illustrated, but a combination of a plurality of other network nodes (for example, MME and S-GW) may be used.

(I / O direction)
Information, signals, and the like can be output from the upper layer (or lower layer) to the lower layer (or upper layer). Input / output may be performed via a plurality of network nodes.

(Handling of input / output information, etc.)
Input / output information and the like may be stored in a specific location (for example, a memory) or may be managed by a management table. Input / output information and the like can be overwritten, updated, or additionally written. The output information or the like may be deleted. The input information or the like may be transmitted to another device.

(Judgment method)
The determination may be performed by a value represented by 1 bit (0 or 1), may be performed by a true / false value (Boolean: true or false), or may be performed by comparing numerical values (for example, a predetermined value) Comparison with the value).

(software)
Software, whether it is called software, firmware, middleware, microcode, hardware description language, or other names, instructions, instruction sets, codes, code segments, program codes, programs, subprograms, software modules , Applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc. should be interpreted broadly.

Further, software, instructions, etc. may be transmitted / received via a transmission medium. For example, software may use websites, servers, or other devices using wired technology such as coaxial cable, fiber optic cable, twisted pair and digital subscriber line (DSL) and / or wireless technology such as infrared, wireless and microwave. When transmitted from a remote source, these wired and / or wireless technologies are included within the definition of transmission media.

(Information, signal)
Information, signals, etc. described herein may be represented using any of a variety of different technologies. For example, data, commands, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of these May be represented by a combination of

Note that the terms described in this specification and / or terms necessary for understanding this specification may be replaced with terms having the same or similar meaning. For example, the channel and / or symbol may be a signal. The signal may be a message. Further, the component carrier (CC) may be called a carrier frequency, a cell, or the like.

("System", "Network")
As used herein, the terms “system” and “network” are used interchangeably.

(Parameter, channel name)
In addition, information, parameters, and the like described in this specification may be represented by absolute values, may be represented by relative values from a predetermined value, or may be represented by other corresponding information. . For example, the radio resource may be indicated by an index.

The names used for the above parameters are not limited in any way. Further, mathematical formulas and the like that use these parameters may differ from those explicitly disclosed herein. Since various channels (eg, PUCCH, PDCCH, etc.) and information elements (eg, TPC, etc.) can be identified by any suitable name, the various names assigned to these various channels and information elements are However, it is not limited.

(base station)
A base station (radio base station) can accommodate one or more (eg, three) cells (also referred to as sectors). When the base station accommodates multiple cells, the entire coverage area of the base station can be partitioned into multiple smaller areas, each smaller area being a base station subsystem (eg, indoor small base station RRH: Remote Radio Head) can also provide communication services. The term “cell” or “sector” refers to part or all of the coverage area of a base station and / or base station subsystem that provides communication services in this coverage. Further, the terms “base station”, “eNB”, “cell”, and “sector” may be used interchangeably herein. A base station may also be referred to in terms such as a fixed station, NodeB, eNodeB (eNB), access point, femtocell, small cell, and the like.

(Terminal)
A user terminal is a mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile by a person skilled in the art It may also be referred to as a terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, UE (User Equipment), or some other appropriate terminology.

(Meaning and interpretation of terms)
As used herein, the terms “determining” and “determining” may encompass a wide variety of actions. “Judgment” and “determination” are, for example, judgment, calculation, calculation, processing, derivation, investigating, looking up (eg, table , Searching in a database or another data structure), considering ascertaining as “determining”, “deciding”, and the like. In addition, “determination” and “determination” include receiving (for example, receiving information), transmitting (for example, transmitting information), input (input), output (output), and access. (accessing) (e.g., accessing data in a memory) may be considered as "determined" or "determined". In addition, “determination” and “decision” means that “resolving”, “selecting”, “choosing”, “establishing”, and “comparing” are regarded as “determining” and “deciding”. May be included. In other words, “determination” and “determination” may include considering some operation as “determination” and “determination”.

The terms “connected”, “coupled”, or any variation thereof, means any direct or indirect connection or coupling between two or more elements and It can include the presence of one or more intermediate elements between two “connected” or “coupled” elements. The coupling or connection between the elements may be physical, logical, or a combination thereof. As used herein, the two elements are radio frequency by using one or more wires, cables and / or printed electrical connections, and as some non-limiting and non-inclusive examples By using electromagnetic energy, such as electromagnetic energy having a wavelength in the region, microwave region, and light (both visible and invisible) region, it can be considered to be “connected” or “coupled” to each other.

The reference signal may be abbreviated as RS (Reference Signal), and may be referred to as a pilot depending on an applied standard. Further, the correction RS may be referred to as TRS (Tracking 、 RS), PC-RS (Phase Compensation RS), PTRS (Phase Tracking RS), or Additional RS. Further, the demodulation RS and the correction RS may be called differently corresponding to each. Further, the demodulation RS and the correction RS may be defined by the same name (for example, the demodulation RS).

As used herein, the phrase “based on” does not mean “based only on”, unless expressly specified otherwise. In other words, the phrase “based on” means both “based only on” and “based at least on.”

The “unit” in the configuration of each device described above may be replaced with “means”, “circuit”, “device”, and the like.

As long as “including”, “comprising”, and variations thereof are used in the specification or claims, these terms are inclusive of the term “comprising”. Intended to be Furthermore, the term “or” as used herein or in the claims is not intended to be an exclusive OR.

The radio frame may be composed of one or a plurality of frames in the time domain. One or more frames in the time domain may be referred to as subframes, time units, etc. A subframe may further be composed of one or more slots in the time domain. The slot may be further configured with one or a plurality of symbols (OFDM (Orthogonal-Frequency-Division-Multiplexing) symbol, SC-FDMA (Single-Carrier-Frequency-Division-Multiple-Access) symbol, etc.) in the time domain.

The radio frame, subframe, slot, and symbol all represent a time unit when transmitting a signal. Radio frames, subframes, slots, and symbols may be called differently corresponding to each.

For example, in the LTE system, the base station performs scheduling to allocate radio resources (frequency bandwidth, transmission power, etc. that can be used in each mobile station) to each mobile station. The minimum time unit of scheduling may be called TTI (Transmission Time Interval).

For example, one subframe may be called a TTI, a plurality of consecutive subframes may be called a TTI, and one slot may be called a TTI.

The resource unit is a resource allocation unit in the time domain and the frequency domain, and may include one or a plurality of continuous subcarriers in the frequency domain. In the time domain of the resource unit, one or a plurality of symbols may be included, and one slot, one subframe, or a length of 1 TTI may be included. One TTI and one subframe may each be composed of one or a plurality of resource units. The resource unit may also be called a resource block (RB: Resource Block), a physical resource block (PRB: Physical RB), a PRB pair, an RB pair, a scheduling unit, a frequency unit, or a subband. Further, the resource unit may be composed of one or a plurality of REs. For example, 1 RE may be any resource (for example, the smallest resource unit) smaller than a resource unit serving as a resource allocation unit, and is not limited to the name RE.

The structure of the radio frame described above is merely an example, and the number of subframes included in the radio frame, the number of slots included in the subframe, the number of symbols and resource blocks included in the slots, and the subframes included in the resource block The number of carriers can be variously changed.

Throughout this disclosure, if articles are added by translation, for example, a, an, and the in English, these articles must be clearly not otherwise indicated by context, Including multiple things.

(Aspect variations, etc.)
Each aspect / embodiment described in this specification may be used independently, may be used in combination, or may be switched according to execution. In addition, notification of predetermined information (for example, notification of being “X”) is not limited to explicitly performed, but is performed implicitly (for example, notification of the predetermined information is not performed). Also good.

Although the present invention has been described in detail above, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

This patent application claims priority from Japanese Patent Application No. 2017-053166 filed on Mar. 17, 2017. The entire contents of Japanese Patent Application No. 2017-053166 are incorporated herein by reference. Incorporate.

One embodiment of the present invention is useful for a mobile communication system.

DESCRIPTION OF SYMBOLS 10 Radio base station 101 Discovery signal generation part 102 Beam number determination part 103 PRS generation part 104,252 Data signal generation part 105,253 Precoding part 106 Weight selection part 107 Transmission beam forming part 151 Reception beam forming part 152 Feedback signal processing part 153 Beam selection unit 154 Positioning unit 155, 205

Post coding unit

156, 206 Data signal processing unit 20 User terminal 203 Reception quality measuring unit 204 Arrival time calculating unit 251 Feedback signal generating unit

Claims

A radio base station that communicates with a user terminal using beam transmission and beam reception,
A beam selection unit that selects a beam having the highest reception quality among the beam candidates as a transmission beam used for data transmission;
A parameter acquisition unit for acquiring a parameter related to the reception quality of a signal transmitted using each of the positioning beams composed of a plurality of beams including the transmission beam;
A positioning unit that estimates the direction of the user terminal using the parameters of each positioning beam;
A wireless base station.
The positioning unit calculates a correction angle based on the parameters in the positioning beam other than the transmission beam, and a direction obtained by correcting the center direction of the transmission beam with the correction angle is defined as the direction of the user terminal. presume,
The radio base station according to claim 1.
The positioning unit calculates the correction angle based on a ratio of received power in the two positioning beams adjacent to the transmission beam;
The radio base station according to claim 2.
A beam number determining unit that adaptively sets the number of positioning beams according to the state of the radio base station;
The radio base station according to claim 1 or 2.