Wireless communication device and wireless transmission method

Abstract

To reduce an interference applied to another communication system.SOLUTION: A radio communication device includes: a plurality of antennas; a radio transmission part that executes radio transmission processing on transmission data transmitted from the plurality of antennas; and a processors connected to the radio transmission part. The processor acquires beam group designation information for designating a beam group which can be formed when transmitting the transmission data, forms at least one beam contained in the beam group, and executes processing of correcting an envelope curve of the beam group containing the formed beam by using a correction coefficient corresponded to the beam group designation information.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a wireless communication device and a wireless transmission method.

Background Art

[0002] Generally, in a wireless communication system used in, for example, a mobile phone, technologies such as MIMO (Multiple Input Multiple Output) and beamforming that utilize a large number of antennas may be introduced in order to increase communication capacity and improve transmission quality. That is, a base station device and a terminal device belonging to a wireless communication system wirelessly transmit and receive signals using a plurality of antennas.

[0003] In MIMO, for example, different signals are simultaneously transmitted from each antenna of a base station device, and signals for each antenna are separated at a terminal device on the receiving side, so that the communication capacity can be increased. In beamforming, for example, by providing a phase difference to signals transmitted from each antenna of a base station device, a beam that increases the gain in the direction of a terminal device on the receiving side is formed, so that the transmission quality is improved and as a result, the communication capacity can be increased.

[0004] In such a wireless communication system, an available radio frequency band is assigned to each. For example, radio frequencies in the 3400 to 4100 MHz band are assigned to a wireless communication system used in a mobile phone and are also assigned to a satellite communication system.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, since the same radio frequency band is assigned to both the wireless communication system and the satellite communication system, there is a problem that interference occurs between the respective communication systems. That is, the signals transmitted and received in the wireless communication system may interfere with the communication of the satellite communication system, or the signals transmitted and received in the satellite communication system may interfere with the communication of the wireless communication system.

[0007] As a result of such interference occurring, in each communication system, the communication capacity and transmission quality deteriorate.

[0008] The disclosed technology has been made in view of such points, and an object thereof is to provide a wireless communication device and a wireless transmission method capable of reducing interference to other communication systems.

Means for Solving the Problems

[0009] The wireless communication device disclosed in the present application, in one aspect, includes a plurality of antennas, a wireless transmission unit that performs wireless transmission processing on transmission data transmitted from the plurality of antennas, and a processor connected to the wireless transmission unit. The processor acquires beam group designation information that designates a beam group that can be formed when transmitting the transmission data, forms at least one beam included in the beam group, and executes a process of correcting an envelope of the beam group including the formed beam using a correction coefficient corresponding to the beam group designation information.

Effects of the Invention

[0010] According to one aspect of the wireless communication device and the wireless transmission method disclosed in the present application, there is an effect that interference to other communication systems can be reduced.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

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Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of a wireless communication device and a wireless transmission method disclosed in the present application will be described in detail with reference to the drawings. Note that the present invention is not limited by this embodiment.

[0013] FIG. 1 is a diagram showing a configuration example of a communication system according to an embodiment. The communication system shown in FIG. 1 includes a CU (Central Unit) / DU (Distributed Unit) 100, an RU (Radio Unit) 200, and a UE (User Equipment) 300.

[0014] The CU / DU 100 is a baseband device that constitutes a base station and performs baseband processing on transmission data and reception data. Specifically, the CU / DU 100 generates transmission data addressed to a plurality of UEs 300 and transmits it to the RU 200 through a fronthaul line. Further, the CU / DU 100 receives reception data received from the UE 300 from the RU 200 through a fronthaul line and performs decoding and the like on the reception data.

[0015] Also, the CU / DU 100 transmits an instruction regarding the beam formed by the RU 200 to the RU 200. That is, the CU / DU 100 transmits beam designation information specifying beams in a plurality of different directions to the RU 200, and instructs the RU 200 to form the beams specified by the beam designation information.

[0016] The RU 200 is a radio communication device constituting a base station, and performs radio processing on transmission data and reception data. Specifically, the RU 200 wirelessly transmits transmission data destined for the UE 300 from an antenna. Also, the RU 200 wirelessly receives data transmitted from the UE 300 via the antenna, and performs predetermined radio reception processing on the reception data.

[0017] The RU 200 includes a plurality of antennas, forms a beam according to an instruction from the CU / DU 100, and wirelessly transmits a signal. At this time, the RU 200 forms the beam specified by the beam designation information. Also, the RU 200 identifies a beam group to which the specified beam belongs based on the beam designation information, and corrects the envelope of the formed beam with a correction coefficient corresponding to the identified beam group. The configuration of the RU 200 will be described in detail later.

[0018] The UE 300 is a terminal device that performs wireless communication with the RU 200. That is, the UE 300 receives a signal wirelessly transmitted from the RU 200 via an antenna, and transmits a signal to the RU 200 via the antenna.

[0019] FIG. 2 is a block diagram showing the configuration of the RU 200 according to an embodiment. In FIG. 2, a processing unit related to transmission is illustrated, and illustration of a processing unit related to reception is omitted. The RU 200 shown in FIG. 2 includes a communication interface unit (hereinafter abbreviated as "communication IF unit") 210, a processor 220, a memory 230, a D / A (Digital / Analog) conversion unit 240, an upconverter 250, and a power amplifier 260.

[0020] The communication IF unit 210 is connected to the CU / DU 100 through the front-haul link and communicates with the CU / DU 100. The communication IF unit 210 receives transmission data destined for a plurality of UEs 300 from the CU / DU 100. Also, the communication IF unit 210 receives beam designation information from the CU / DU 100.

[0021] The processor 220 is a signal processing unit including, for example, a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or a DSP (Digital Signal Processor), and comprehensively controls the entire RU 200. Specifically, the processor 220 includes a weight coefficient control unit 221, a beamforming unit 222, a multiplexing unit 223, an envelope correction unit 224, and an IFFT (Inverse Fast Fourier Transform) processing unit 225.

[0022] The weight coefficient control unit 221 acquires beam designation information from the communication IF unit 210 and holds weight coefficients for forming each beam designated by the beam designation information. Then, when the beam designation information from the CU / DU 100 is received by the communication IF unit 210, the weight coefficient control unit 221 outputs weight coefficients for forming a beam corresponding to the beam designation information to the beamforming unit 222. Also, the weight coefficient control unit 221 identifies a beam group to which the beam designated by the beam designation information belongs from among a plurality of beam groups, and notifies the identified beam group to the envelope correction unit 224, thereby setting a correction coefficient for correcting the envelope of the beam group.

[0023] The beamforming unit 222 acquires transmission data destined for a plurality of UEs 300 from the communication IF unit 210, and forms a beam for transmitting the transmission data using the weight coefficients output from the weight coefficient control unit 221. Specifically, the beamforming unit 222 branches the transmission data destined for each UE 300 into the number of logical antenna ports, and multiplies the weight coefficients by the transmission data corresponding to each logical antenna port, thereby forming a beam for the transmission data destined for each UE 300.

[0024] The multiplexing unit 223 multiplexes the transmission data destined for a plurality of UEs 300. Then, the multiplexing unit 223 outputs the stream data for each logical antenna port in which the transmission data destined for a plurality of UEs 300 is multiplexed to the envelope correction unit 224.

[0025] When the envelope correction unit 224 is notified of the beam group information from the weight coefficient control unit 221, it sets the correction coefficient corresponding to the beam group, and corrects the stream data using the correction coefficient, thereby correcting the envelope of the beam group. Specifically, the envelope correction unit 224 generates antenna streams of the number of physical antenna ports by performing a matrix operation of multiplying a matrix of correction coefficients on a plurality of stream data for each logical antenna port. Here, the matrix of correction coefficients multiplied on the plurality of stream data is for reducing or increasing the width of the envelope of the beam group notified from the weight coefficient control unit 221, and corrects the entire beams included in the beam group at once.

[0026] FIG. 3 is a diagram showing a configuration example of the envelope correction unit 224. As shown in FIG. 3, when streams #1 to #m corresponding to, for example, m logical antenna ports are input to the envelope correction unit 224, the envelope correction unit 224 outputs antenna streams #1 to #n corresponding to, for example, n physical antenna ports. The envelope correction unit 224 includes a multiplier that multiplies the correction coefficient corresponding to the beam group on streams #1 to #m, and an adder that adds the multiplication results of the multipliers for each of the streams #1 to #m. Then, the envelope correction unit 224 branches each of the m streams #1 to #m into n signals, multiplies the correction coefficient on each of the branched signals, and adds the n multiplication results for each stream, thereby generating n antenna streams #1 to #n. That is, the envelope correction unit 224 generates antenna streams #1 to #n by performing a matrix operation of multiplying a matrix of correction coefficients of n rows and m columns on streams #1 to #m.

[0027] The correction coefficient matrix corresponds to a beam group and changes the width of the envelope of this beam group. That is, for example, as shown in FIG. 4(a), when a plurality of beams 401 included in the beam group form an envelope 402, the correction coefficient is a correction coefficient that reduces the width of the envelope 402 as shown in FIG. 4(b) or increases the width of the envelope 402 as shown in FIG. 4(c). Such correction coefficients are obtained in advance for each beam group so that beams in the direction where cross-interference should be avoided are not formed. That is, for example, correction coefficients for correcting the envelope of the beam group so that beams are not formed in the direction that interferes with the communication of a satellite communication system are obtained in advance for each beam group.

[0028] Then, for example, by correcting the stream data with a correction coefficient that reduces the width of the envelope of the beam group, it is possible to avoid beam formation in the direction where interference occurs with other communications such as a satellite communication system. Also, for example, by correcting the stream data with a correction coefficient that increases the width of the envelope of the beam group, it is possible to form beams using the direction where no interference occurs with other communications to the maximum extent, and improve the transmission quality and communication capacity.

[0029] Returning to FIG. 2, the IFFT processing unit 225 performs IFFT processing on the antenna stream of the number of physical antenna ports, and converts the antenna stream in the frequency domain into an antenna stream in the time domain. The IFFT processing unit 225 outputs the antenna stream converted into a signal in the time domain to the D / A conversion unit 240 corresponding to each physical antenna port.

[0030] The memory 230 includes, for example, a RAM (Random Access Memory) or a ROM (Read Only Memory), and stores information used for processing by the processor 220.

[0031] The D / A conversion unit 240 is provided for each physical antenna port and performs D / A conversion on each antenna stream.

[0032] The upconverter 250 is provided for each physical antenna port, upconverts each antenna stream, and converts the antenna stream into a radio frequency signal.

[0033] The power amplifier 260 is provided for each physical antenna port, amplifies each antenna stream, and wirelessly transmits each antenna stream from the antenna connected to the physical antenna port.

[0034] Next, a wireless transmission method using the RU200 configured as described above will be described with reference to the flowchart shown in FIG. 5.

[0035] The CU / DU 100 transmits transmission data for causing the RU200 to wirelessly transmit to a plurality of UEs 300 to the RU200. Also, the CU / DU 100 transmits beam designation information for designating a beam to be used for the transmission of these transmission data to the RU200. Then, when the communication IF unit 210 of the RU200 receives transmission data addressed to a plurality of UEs 300, these transmission data are acquired by the beam forming unit 222 (step S101). Also, when the communication IF unit 210 receives beam designation information when transmitting the transmission data, the beam designation information is acquired by the weight coefficient control unit 221 (step S102).

[0036] Then, the weight coefficient control unit 221 identifies the beam group to which the beam designated by the beam designation information belongs from among a plurality of predefined beam groups (step S103). That is, since all the beams designated by the beam designation information belong to the same beam group, this one beam group is identified. The identified beam group is notified to the envelope correction unit 224, and a correction coefficient corresponding to the beam group, which corrects the envelope of the beam group, is set in the envelope correction unit 224 (step S104).

[0037] On one hand, the weight coefficient control unit 221 outputs the weight coefficients for forming the beam specified by the beam designation information to the beam forming unit 222. Then, the beam forming unit 222 forms a beam when transmitting the transmission data destined for a plurality of UEs 300 by using the weight coefficients (step S105). That is, the transmission data destined for each UE 300 is branched into the number of logical antenna ports, and the weight coefficients are multiplied by the transmission data corresponding to each logical antenna port.

[0038] The transmission data destined for each UE 300 corresponding to the logical antenna port is multiplexed by the multiplexing unit 223 (step S106), and the stream data for each logical antenna port is output to the envelope correction unit 224. Then, the envelope correction unit 224 performs correction on the beam to change the width of the envelope of the beam group by matrix operation between the stream data for each logical antenna port and the matrix of correction coefficients (step S107). That is, the stream data is branched into the number of physical antenna ports, the correction coefficients are multiplied by the stream data corresponding to each physical antenna port, and the multiplication results are added for each physical antenna port, thereby generating an antenna stream for each physical antenna port.

[0039] The antenna stream is converted from a signal in the frequency domain to a signal in the time domain by performing IFFT processing by the IFFT processing unit 225 (step S108). Then, each antenna stream is D / A converted by the D / A conversion unit 240 provided for each physical antenna port, up-converted by the up-converter 250, and amplified by the power amplifier 260. The amplified antenna stream is wirelessly transmitted from the antenna connected to each physical antenna port (step S109). At this time, since the weight coefficients are multiplied by the transmission data by the beam forming unit 222, a beam is formed, and since the correction for controlling the width of the envelope is performed by the envelope correction unit 224, it is possible to suppress the occurrence of interference with other communications such as a satellite communication system.

[0040] As described above, according to this embodiment, a beam specified by beam specification information is formed, and the beam is corrected so as to change the width of the envelope of the beam group by using a correction coefficient corresponding to the beam group to which these beams belong. For this reason, it is possible to reduce the interference given to other communication systems by preventing beams from being formed in the direction in which communication of other communication systems is performed.

[0041] In the above-described embodiment, the envelope of the beam group is corrected by matrix operation between the stream data for each logical antenna port and the matrix of correction coefficients. However, it is also possible to correct the envelope of the beam group by matrix operation between the weight coefficient for each logical antenna port and the matrix of correction coefficients. FIG. 6 is a block diagram showing a modification example of the RU200 in the case of correcting the weight coefficient. In FIG. 6, the same parts as those in FIG. 2 are denoted by the same reference numerals. The RU200 shown in FIG. 6 has an envelope correction unit 224a instead of the envelope correction unit 224 shown in FIG. 2.

[0042] When the envelope correction unit 224a is notified of the information of the beam group from the weight coefficient control unit 221, the envelope correction unit 224a sets a correction coefficient corresponding to the beam group and corrects the weight coefficient by using the correction coefficient, thereby correcting the envelope of the beam group. Specifically, the envelope correction unit 224a generates corrected weight coefficients for the number of physical antenna ports by performing a matrix operation of multiplying a matrix of correction coefficients by a plurality of weight coefficients for each logical antenna port. Here, the matrix of correction coefficients multiplied by the plurality of weight coefficients is for reducing or increasing the width of the envelope of the beam group notified from the weight coefficient control unit 221, and corrects the entire beams included in the beam group at once.

[0043] FIG. 7 is a diagram showing a configuration example of the envelope correction unit 224a. As shown in FIG. 7, when, for example, weight coefficients #1 to #m corresponding to m logical antenna ports are input to the envelope correction unit 224a, the envelope correction unit 224a outputs correction weight coefficients #1 to #n corresponding to, for example, n physical antenna ports. The envelope correction unit 224a includes a multiplier that multiplies the weight coefficients #1 to #m by correction coefficients corresponding to the beam group, and an adder that adds the multiplication results of the multiplier for each of the weight coefficients #1 to #m. Then, the envelope correction unit 224a branches each of the m weight coefficients #1 to #m into n signals, multiplies each of the branched signals by a correction coefficient, and adds the n multiplication results for each weight coefficient to generate n correction weight coefficients #1 to #n. That is, the envelope correction unit 224a generates the correction weight coefficients #1 to #n by performing a matrix operation of multiplying the weight coefficients #1 to #m by a matrix of correction coefficients of n rows and m columns.

[0044] The beam forming unit 222 forms a beam for the transmission data addressed to each UE 300 by multiplying the transmission data addressed to a plurality of UEs 300 by the correction weight coefficients #1 to #n. The beam formed in this way is a beam in which the envelope of the beam group is corrected, and the interference given to other communication systems can be reduced.

[0045] In the above embodiment, the envelope of the beam group is corrected for the signal in the frequency domain, but it is also possible to correct the envelope of the beam group for the signal in the time domain. FIG. 8 is a block diagram showing a modification example of the RU 200 when correcting the signal in the time domain. In FIG. 8, the same parts as those in FIG. 2 are denoted by the same reference numerals. The RU 200 shown in FIG. 8 has an envelope correction unit 224b arranged at the subsequent stage of the IFFT processing unit 225 instead of the envelope correction unit 224 of the RU 200 shown in FIG. 2.

[0046] When the envelope correction unit 224b is notified of the information of the beam group from the weight coefficient control unit 221, it sets a correction coefficient corresponding to the beam group, and corrects the stream data, which is a signal in the time domain converted by the IFFT processing unit 225, thereby correcting the envelope of the beam group. Specifically, the envelope correction unit 224b generates antenna streams of the number of physical antenna ports by performing a matrix operation of multiplying a matrix of correction coefficients on the stream data for each logical antenna port. Here, the matrix of correction coefficients multiplied on the plurality of stream data is for reducing or increasing the width of the envelope of the beam group notified from the weight coefficient control unit 221, and corrects the entire beams included in the beam group collectively.

[0047] In this way, by correcting the stream data converted into a signal in the time domain by the IFFT processing unit 225, the envelope of the beam group can be corrected, and the interference given to other communication systems can be reduced.

Explanation of Signs

[0048] 210 Communication IF Unit 220 Processor 221 Weight Coefficient Control Unit 222 Beam Forming Unit 223 Multiplexing Unit 224, 224a, 224b Envelope Correction Unit 225 IFFT Processing Unit 230 Memory 240 D / A Conversion Unit 250 Upconverter 260 Power Amplifier

Claims

1. A plurality of antennas, a wireless transmission unit that performs wireless transmission processing on transmission data transmitted from the plurality of antennas, and a processor connected to the wireless transmission unit, wherein the processor acquires beam group designation information for designating a beam group that can be formed when transmitting the transmission data, forms at least one beam included in the beam group, and corrects an envelope of the beam group including the formed beam using a correction coefficient corresponding to the beam group designation information, executes a process, wherein the correction coefficient is a matrix obtained in advance for each beam group so that a beam in a direction in which interference should be avoided is not formed, and corrects the envelope of the beam group so that a beam in a direction that interferes with the communication of another system is not formed, and a wireless communication device characterized by this.

2. The process of correcting is characterized in that a matrix operation of multiplying a matrix of the correction coefficient is performed on a plurality of transmission data corresponding to the plurality of antennas, as described in Claim 1 of the wireless communication device.

3. The process of correcting is characterized in that the envelope of the beam group is corrected by multiplying the correction coefficient by the transmission data in the frequency domain, as described in Claim 1 of the wireless communication device.

4. The processor further executes a process of converting the transmission data in the frequency domain into transmission data in the time domain, and the process of correcting is characterized in that the envelope of the beam group is corrected by multiplying the correction coefficient by the transmission data in the time domain, as described in Claim 1 of the wireless communication device.

5. A plurality of antennas, a wireless transmission unit that performs wireless transmission processing on transmission data transmitted from the plurality of antennas, and a processor connected to the wireless transmission unit, wherein the processor acquires beam group designation information for designating a beam group that can be formed when transmitting the transmission data, corrects a weight coefficient for forming a beam included in the beam group using a correction coefficient corresponding to the beam group designation information, the correction coefficient being a correction coefficient that changes the envelope of the beam group, and forms a beam for transmitting the transmission data using the corrected weight coefficient, executes a process, wherein the correction coefficient is a matrix obtained in advance for each beam group so that a beam in a direction in which interference should be avoided is not formed, and corrects the envelope of the beam group so that a beam in a direction that interferes with the communication of another system is not formed, The wireless communication device is characterized in that the weight coefficient is a matrix for collectively correcting all the beams included in the beam group. **Claim 6** The correction process The wireless communication device according to claim 5, wherein the correction process executes a matrix operation of multiplying the matrix of the correction coefficient by a plurality of weight coefficients corresponding to the plurality of antennas. **Claim 7** A wireless transmission method executed by a wireless communication device having a plurality of antennas, comprising: obtaining beam group designation information for designating a beam group that can be formed when transmitting transmission data from the plurality of antennas; forming at least one beam included in the beam group; correcting an envelope of the beam group including the formed beam using a correction coefficient corresponding to the beam group designation information; The wireless transmission method is characterized in that the correction coefficient is a matrix for correcting the envelope of the beam group so that a beam in a direction that should avoid co-interference is not formed for each beam group, and so that a beam is not formed in a direction that interferes with the communication of other systems, which is obtained in advance. ​

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