WO2018117335A1

WO2018117335A1 - Method and apparatus for antenna phase correction in large-capacity antenna system

Info

Publication number: WO2018117335A1
Application number: PCT/KR2017/002745
Authority: WO
Inventors: 심세준; 김종돈; 양하영; 이주현; 최찬호
Original assignee: 삼성전자 주식회사
Priority date: 2016-12-23
Filing date: 2017-03-14
Publication date: 2018-06-28

Abstract

The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data transfer rate than a 4G communication system such as LTE. The method according to an embodiment of the present invention is a method for phase correction of an antenna in a large-capacity antenna system, the method comprising the steps of: grouping large-capacity antennas into a predetermined number of groups; setting a path such that ports of the grouped antennas have a feedback path; outputting a test signal to be outputted to each antenna port of each group by adding a code or sequence having orthogonality; separating signals for each antenna port in the group by using the code or sequence having orthogonality in a signal received through the feedback path; and calculating a calibration value by detecting a phase change of the separated signal. This research was carried out with the support of "Cross-Ministry Giga Korea Project" of the Ministry of Science, ICT and Future Planning, Republic of Korea.

Description

Antenna phase correction method and device in large capacity antenna system

The present invention relates to a method and apparatus for correcting the phase of an antenna in a large capacity antenna system.

This study was supported by the Ministry of Science, ICT and Future Planning 'Giga KOREA Project'.

In order to meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems, efforts are being made to develop improved 5G communication systems or pre-5G communication systems. For this reason, a 5G communication system or a pre-5G communication system is referred to as a Beyond 4G network communication system or a post LTE system.

In order to achieve high data rates, 5G communication systems are being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Gigabit (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and to increase the transmission distance of radio waves, beamforming, massive array multiple input / output (FD-MIMO) in 5G communication systems Array antenna, analog beam-forming, and large scale antenna techniques are discussed.

In addition, in order to improve the network of the system, 5G communication system has evolved small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense network , Device to device communication (D2D), wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation The development of such technology is being done.

In addition, in 5G systems, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC), Advanced Coding Modulation (ACM), and FBMC (Filter Bank Multi Carrier) and NOMA (non orthogonal multiple access), and sparse code multiple access (SCMA), and the like are being developed.

As described above, in the case of employing a massive MIMO antenna system, a technique for performing phase alignment between antennas by acquiring phase information between antennas in advance is required. This technique of utilizing phase alignment is called an antenna calibration technique. Antenna correction techniques are commonly utilized when using beamforming (BF). For antenna calibration, a process of estimating phase information for each antenna is required by transmitting a predetermined calibration signal.

The large-capacity multiple input / multi-output system uses a large-capacity antenna to increase the signal-to-noise ratio (SNR) of the transmitted / received signals in order to improve data transmission efficiency. It is standardized to dimension multiple-input multiple-output (FD-MIMO), and is also discussed as a key element technology in 5G communication systems.

When performing antenna calibration in a large capacity multiple input / multi output system, a large number of antennas need to be calibrated, so the time required for antenna calibration is increased. In addition, it is a burden on the system that the antenna correction should be performed while the normal communication service is suspended in the time required for antenna correction. In particular, in a large-capacity multiple input / multi output system, since the antenna correction must be performed for each of a large number of antennas, the time required for antenna correction is further increased. If antenna calibration takes such a long time, the system increases the time required to stop the scene, which can be very burdensome.

Therefore, there is a need for an apparatus and method for reducing the time required for antenna calibration in a large capacity multiple input / multi output system.

Accordingly, the present invention provides an apparatus and method which may be time required for antenna correction in a large capacity multiple input / multi output system.

The present invention provides a method and apparatus for reducing the burden of the system by reducing the antenna correction time in a large capacity multiple input / multiple output system.

According to an embodiment of the present invention, there is provided a method of correcting a phase of an antenna in a large capacity antenna system, the method comprising: grouping the large capacity antennas into a predetermined number of groups; Establishing a path such that the grouped antenna ports have a feedback path; Adding a code or sequence having orthogonality to test signals to be output to each antenna port of each group; Separating a signal for each antenna port in the group using the orthogonal code or sequence from the signal received through the feedback path; And calculating a compensation value by detecting a phase change of the separated signal.

An apparatus according to an embodiment of the present invention is a device for phase correction of an antenna in a large-capacity antenna system, including antenna ports corresponding to each antenna, and including a feedback port grouped by the predetermined number of antennas. Wireless unit; A switching and A / D converter including transmission / reception switches corresponding to respective antenna ports of the radio unit and analog-to-digital converters corresponding to the transmission / reception switches; And controlling the setting of a path so that the grouped antenna ports have a feedback path, generating a test signal to be output to each antenna port of each group, and adding different codes or sequences having orthogonality to each generated test signal. A modem for outputting the signal, separating the signal for each antenna port in the group using the code or sequence having the orthogonality from the signal received through the feedback path, and detecting a phase change of the separated signal to calculate a compensation value It can include;

An apparatus according to another embodiment of the present invention is a device for phase correction of an antenna in a high-capacity antenna system, including a radio port corresponding to each antenna, and a wireless unit including a feedback port corresponding to each antenna port. ; Switching and A / D conversion including transmission / reception switches corresponding to respective antenna ports of the radio unit and analog-to-digital converters corresponding to the transmission / reception switches and receiving a signal output from the feedback ports. part; And a modem for generating and outputting a test signal to be output to each of the antenna ports, and detecting a phase change from a signal received through each feedback path to calculate a compensation value.

In the present invention according to the present invention, the use of a large capacity multiple input / multiple output system, there is an advantage that can reduce the time required for antenna correction to reduce the burden on the system, and increase the efficiency of communication.

1 is a functional block diagram of a large capacity multiple input / multi output (massive MIMO) antenna system.

2 is a configuration diagram for correcting a reception phase of antennas in a large capacity multiple input / multi output antenna system.

3 is a configuration diagram for correcting a transmission phase of antennas in a large capacity multiple input / multi output antenna system.

4 is an output timing diagram of a test signal output for testing each antenna port in a modem.

5 is a configuration diagram for correcting the transmission phase of the antennas in a large capacity multiple input / multiple output antenna system according to an embodiment of the present invention.

6A and 6B are timing diagrams illustrating a case in which a test signal is transmitted for each group according to an exemplary embodiment of the present invention.

7 is a control flowchart when a transmission phase of antennas is corrected in a large capacity multiple input / multi output antenna system according to an exemplary embodiment of the present invention.

8 is a block diagram for correcting the transmission phase of the antennas in a large capacity multiple input / multiple output antenna system according to another embodiment of the present invention.

9 is a block diagram for correcting the transmission phase of the antennas in a large capacity multiple input / multiple output antenna system according to another embodiment of the present invention.

Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings. In this case, it should be noted that like elements are denoted by like reference numerals as much as possible. In addition, the accompanying drawings of the present invention is provided to aid the understanding of the present invention, it should be noted that the present invention is not limited to the form or arrangement illustrated in the drawings of the present invention. In addition, detailed descriptions of well-known functions and configurations that may blur the gist of the present invention will be omitted. In the following description, only parts necessary for understanding the operation according to various embodiments of the present invention are described, and it should be noted that the descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

In general, a large capacity multiple input / multi output antenna system is generally employed in a base station. Therefore, the case of Figure 1 also assumes the case of the base station will be described. However, in some cases, the terminal may be employed and may be applied in the same or similar form within the spirit of the present invention.

As illustrated in FIG. 1, a large capacity multiple input / multi output antenna system includes a very large number of antennas.

Antennas

1, 2, 3,... , k-2, k-1, and k are connected to the radio unit 10 and are located at the terminal for transmitting / receiving a signal. Here k representing the number of antennas may be a very large number.

The radio unit 10 has

antennas

1, 2, 3,... , signals k-2, k-1, k, or

antennas

1, 2, 3,... may include ports (not shown in FIG. 1) for receiving signals from k-2, k-1, and k. In addition, the radio unit 10 converts a signal into a band required by a corresponding system and outputs the converted signal, and converts and outputs a signal received from a specific antenna or a plurality of antennas into a signal of an intermediate frequency or baseband. Configurations of the wireless unit 10 required for the description of the present invention will be described with reference to the drawings to be described later.

The switching and A / D converter 20 separates a path for transmitting a signal from a path for receiving a signal, switches the signal, converts an analog signal received from the radio unit 10 into a digital signal, and outputs the digital signal received from the modem. Convert to analog signal and output. Configuration of the switching and A / D conversion unit 20 required for the description of the present invention will also be described in more detail in the following drawings.

Modem 30 may be arranged in accordance with the invention in accordance with the

respective antennas

1, 2, 3,. , and generates and outputs signals for processing k-2, k-1, and k, and controls the routing and routing of signals in the A / D converter 20 and the wireless unit 10. In addition, the modem 30 has the

antennas

1, 2, 3,... The signals for correcting the phases of the antennas may be measured corresponding to the transmission path and the reception path with k-2, k-1, and k, and compensation may be performed according to the measured result. The modem 30 may be configured in the form of a communication processor to control the above-described operation. In addition, although not illustrated in the drawings, the modem 30 may include a memory for measuring a phase of a signal, storing measured information, and storing correction information. When the modem 30 does not include a memory, the above-described data may be stored or read in a separate memory (not illustrated in FIG. 1) provided externally. This specific operation will be described in more detail in the following drawings.

The controller 40 performs overall control of the base station. For example, the controller 40 controls transmission / reception of data and / or signals with a specific electronic device located in its cell. In addition, the controller 40 may perform scheduling for transmission / reception of data with a specific electronic device. In addition, the controller 40 may control to communicate with other devices connected to the upper network. Most of the control performed by the base station may be performed by the control unit 40. Since these control operations are well known, further description thereof will be omitted.

Hereinafter, a configuration and operation of correcting for reception of antennas in a large capacity multiple input / multi output antenna system will be described with reference to FIG. 2. In addition, in FIG. 2, lines corresponding to a reception operation are denoted by solid lines in order to explain measurement of a reception phase, and lines related to a transmission operation not related to reception of a signal are denoted by a dotted line. In addition, a detailed operation of the transmission will be described in more detail with reference to the accompanying drawings.

First, the configuration of FIG. 2 will be described. The

antenna ports

11, 12, 13,... Corresponding to the number of antennas are located inside the radio unit 10. , 1k and a separate transmit feedback port 101. That is, antenna port # 1 11 of the radio unit 10 corresponds to antenna 1, antenna port # 2 12 corresponds to antenna 2, antenna port # 3 13 corresponds to antenna 3, and antenna port #k 1k corresponds to antenna k. Corresponds to. Accordingly, each

antenna port

11, 12, 13,... , 1k is basically the

antennas

1, 2, 3,... The signals received from k-2, k-1, and k may be output to the switching and A / D converter 20. In addition, the wireless unit 10 transmits a test signal for a test to each

antenna port

11, 12, 13,. And a feedback feedback port 101 for feedback back to 1k.

Next, the configuration of the switching and A / D converter 20 will be described with reference to the

antenna ports

11, 12, 13,. , Transmit / receive

switches

211, 212, 213,... Corresponding to 1k. , 21k and A /

D converters

221, 222, 223,... Contains 22k. Transmit / receive

switches

211, 212, 213,... , 21k denotes each of the

antenna ports

11, 12, 13,... , 1k and 1: 1 can be mapped. As illustrated in FIG. 2, the antenna port # 1 11 of the radio unit 10 corresponds to the transmit / receive switch # 1 211 of the switching and A / D converter 20, and the antenna port # 2 12 corresponds to the transmit / receive switch # 2 212. Antenna port # 3 13 corresponds to transmit / receive switch # 3 213, and antenna port #k 1k corresponds to transmit / receive switch #k 21k. Also, as illustrated in FIG. 2, the transmit / receive

switches

211, 212, 213,... , 21k are the respective A /

D converters

221, 222, 223,... Corresponds to 22k.

The respective A /

D converters

221, 222, 223,... 22k may include a D / A converter for converting a digital signal to be transmitted therein into an analog signal and a band-up converter for band-up converting the converted analog signal. A /

D converters

221, 222, 223,... The 22k may include a band down converter for converting a high frequency signal of a band received therein into an intermediate frequency or baseband signal, and an A / D converter for converting a band down converted analog signal into a digital signal. In FIG. 2, a form including all of these components is illustrated as an A / D converter.

Finally, the modem 30 has its own A /

D converters

221, 222, 223,... It may include a signal calculation unit or a signal calculation module corresponding to 22k. In FIG. 2,

compensation signal calculators

311, 312, 313,... , 31k is illustrated. In addition, the modem 30 may include a reception port test signal transmitter 301 for generating and transmitting a reception port test signal. Such a transmitter and a calculator may be configured by hardware modules, hardware logic, software, or firmware.

In the case of the above configuration, the operation of measuring the phase of a receiving antenna in a large capacity multiple input / multi output antenna system will be described. First, the reception port test signal transmitter 301 performs the

antenna ports

11, 12, 13,. In step 1k, a test signal for checking the phase of the received signal is generated and output to the switching and A / D converter 20. At this time, the test signal is a signal previously known to the modem 30.

The test signal output from the reception port test signal generator 301 may be converted into an analog signal through one of the plurality of A / D converters, and may be band-up converted and output. FIG. 2 illustrates a case in which the A / D converter #k 22k illustrated in the last example converts a digital test signal into an analog test signal, and performs band-up conversion. However, it may be output through another A / D converter illustrated in FIG. 2 or through a separate A / converter (not illustrated in FIG. 2).

A / D converter #k 22k is converted into an analog signal and output the test signal to the transmit feedback port 101. Transmit feedback port 101 is each of the

antenna ports

11, 12, 13,... It is connected to a feedback path for providing a signal at 1k. Therefore, the test signal output from the transmission feedback port 101 is applied to all

antenna ports

11, 12, 13,... The same test signal is input at 1k. Accordingly, each

antenna port

11, 12, 13,... , 1k may receive the same test signal at the same time. The

antenna ports

11, 12, 13,... , The test signal received at 1k is the transmit / receive

switches

211, 212, 213,... Corresponding to the respective antenna ports. , 21k is entered.

Transmit / receive

switches

211, 212, 213,... Since 21k is a configuration for switching the paths of the transmission signal and the reception signal, the test signal can be switched to the reception route by the control of the modem 30 or by the control of the controller 40. In FIG. 2, since the lines of the drawing are complicated, these control lines are not shown, only the signal transmission / reception paths are shown.

The

antenna ports

11, 12, 13,... , Transmit / receive

switches

211, 212, 213,. , The test signal connected to the receive path through 21k is then applied to the respective A /

D converters

221, 222, 223,... , 22k. The respective A /

D converters

221, 222, 223,... , 22k is a band-down conversion of the test signal of the rising band, and then converted to a digital signal and output. As such, the respective A /

D converters

221, 222, 223,... , The signal output from 22k is returned to each antenna port

compensation signal calculator

311, 312, 313,... , 31k.

Antenna port

compensation signal calculators

311, 312, 313,... , 31k may detect the change in phase by using a known transmission signal after receiving the input test signal fed back. When the phase change is detected in this manner, the phase change in the reception path can be calculated by contrasting the phase of the received signal from the transmitted signal. Thus, the modem 30 may select the

antenna ports

11, 12, 13,. , Phase correction may be performed for each antenna with respect to reception paths corresponding to 1k.

As described above, the compensation for the received signal can easily detect a phase change for each path through the feedback path by transmitting one signal. Through this, the phase may be corrected from a table in which necessary phase correction values are stored for each reception path, or the phase of an antenna may be adjusted for each reception path through a preset correction operation.

Next, a configuration and operation of correcting a transmission phase of an antenna in a large capacity multiple input / multi output antenna system will be described with reference to FIG. 3. In FIG. 3, unlike FIG. 2, the configuration for explaining the measurement of the transmission phase is indicated by the solid line corresponding to the transmission operation, and the lines related to the reception operation not related to the transmission of the signal are indicated by the dotted line.

Looking at the configuration of Figure 3 in contrast to Figure 2, the basic configuration is all the same. However, the radio receiver 10 includes a reception feedback port 102, and each of the

antenna ports

11, 12, 13,... , 1k is a path connected to the reception feedback port 102. That is, the signals output from the respective antenna ports are not directly output to the antenna, but are connected to the reception feedback port 102 configured for the test.

In addition, the modem 30 generates signals to be output to each antenna port and outputs the signals to the switching and A / D converter 20. The configuration of the switching and A / D converter 20 has the same configuration as that of FIG. Thus, the switching and A / D conversion section 20 is connected to the

respective antenna ports

11, 12, 13,. , Transmit / receive

switches

211, 212, 213,... Corresponding to 1k. , 21k and A /

D converters

221, 222, 223,... Contains 22k. Transmit / receive

switches

211, 212, 213,... , 21k denotes each of the

antenna ports

11, 12, 13,... , 1k and 1: 1 can be mapped. Transmit / receive

switches

211, 212, 213,... , 21k are the respective A /

D converters

221, 222, 223,... Corresponds to 22k. As described above, each of the A /

D converters

221, 222, 223,... The 22k may include a D / A converter for converting a digital signal to be transmitted into an analog signal and a band-up converter for band-up converting the converted analog signal, and the A /

D converters

221, 222, 223, … The 22k may include a band down converter for converting a high frequency signal of a band received therein into an intermediate frequency or baseband signal, and an A / D converter for converting a band down converted analog signal into a digital signal.

Next, the operation for correcting the transmission phase of the antennas in the large capacity multiple input / multi output antenna system having the above configuration will be described.

Modem 30 has

respective antenna ports

11, 12, 13,... In addition, a signal for outputting at 1k is generated, and a test signal is sequentially generated corresponding to each antenna port and output. At this time, the test signal is a signal that the modem 30 knows in advance. Then each of the A /

D converters

221, 222, 223,... , 22k converts the input test signal into an analog signal, and band-up converts the outputted test signal. The respective A /

D converters

221, 222, 223,... At 22k, the transmit / receive

switches

211, 212, 213,... Output is made by setting the transmission path to the antenna port at 21k. Then each

antenna port

11, 12, 13,... At 1k, the transmission signal is fed back to the reception feedback port 102.

The receive feedback port 102 sends the input signal back to the A /

D converters

221, 222, 223,. , 22k. 3 illustrates an example of inputting the A / D converter #k 22k shown at the end. Therefore, the A / D converter #k 22k converts the input signal back down, converts the analog signal into a digital signal, and outputs the signal to the modem 30.

At this time, since a large number of multiple input / multiple output antenna system has a very large number of antennas, the antenna ports of the radio unit 10 has a very large number of antenna ports corresponding to a very large number of antennas. In contrast, as illustrated in FIG. 3,

antenna ports

11, 12, 13,. We have only one port for feedback test signal from 1k. Therefore, when signals are transmitted to all the antenna ports at once, all the signals are input in a mixed state at the reception feedback port 102. Therefore, there is a problem in that it is not possible to distinguish which signal is input from the antenna port. Therefore, the modem 30 may output a test signal to be output to each antenna port in a continuous form in time.

As shown in FIG. 3, when transmitting a test signal for a transmission path, the reason for leaving only one path of the reception feedback port 102 is to transmit a test signal to measure a phase, and when compensation is performed, a phase between each reception path. And to exclude additional considerations due to differences in amplitude.

4, each

antenna port

11, 12, 13,... , Test signals 401, 402, 403, ... sequentially in 1k. , 40k is outputted. That is, the test signal 401 for outputting to the antenna port # 1 11 is output from the modem 30 from the time point t0 to the time point t1, and the test signal for outputting to the second antenna port # 2 12 from the time point t11 to the time point t12. 402 is output from the modem 30, and a test signal 403 for outputting to the antenna port # 3 13 is output from the modem 30 from the time point t2 to the time point t3, and the time point t (k) from the time point t (k-1). So far, the test signal 40k for outputting to the k-th antenna port #k 1k is output from the modem 30. Here, the figure of FIG. 4 is illustrated without considering the time for changing the output path of some signals between the respective test signals.

Therefore, in the receiving feedback port 102, the

antenna ports

11, 12, 13,... Each of the test signals is input from 1k to the form as shown in FIG. 4, and as a result, the input to the A / D converter 22k is the same. Accordingly, each

antenna port

11, 12, 13,... For example, the phase of each antenna port can be measured by receiving a test signal for 1k.

However, in the method described above, since the signal must be transmitted for each antenna port in the modem 30, the phase path of the transmission path and the correction for each antenna port are proportional to the number of antennas and the processing time of the modem 30. There is a very time consuming problem.

Referring to FIG. 5, the basic block configuration may be understood to be the same as the configuration of FIGS. 2 and 3 described above. In FIG. 5, grouping is performed in units of a plurality of antenna ports to process a transmission test signal. In FIG. 5, antenna ports are shown in a form of two groups for convenience of description. However, unlike illustrated in FIG. 5, antenna ports may be grouped into two or more groups.

First, the configuration of FIG. 5 will be described. The

respective antenna ports

11, 12,... , 1 (k-p-1) is formed in one group and is input to one receiving feedback port # 1 111. Also in another group of antenna ports 1 (k-p), 1 (k-p + 1),... , 1k is input to the other receiving feedback port # 2 112. Each

antenna port

11, 12,... , 1 (k-p-1), 1 (k-p), 1 (k-p + 1),... 1k denotes each of the transmit / receive

switches

211, 212,... Included in the respective switching and A / D converters 20 as described above. , 21 (k-p), 21 (k-p + 1),... 1: 1 mapped to 21k. Also, each of the transmit / receive

switches

211, 212,... , 21 (k-p), 21 (k-p + 1),... 21k represents the respective A /

D converters

221, 222,. , 22 (k-p-1), 22 (k-p), 22 (k-p + 1),... , 1: 1 mapped with 22k.

In contrast to FIG. 3, the radio section 10 has a plurality of receiving feedback ports, such as the receiving feedback port # 1 111 and the receiving feedback port # 2, each of the receiving

feedback ports

111 and 112 is an A / D converter in a corresponding group. The path is set to output a signal to the channel. In FIG. 5, the feedback path of the reception feedback port # 1 111 is input to the A / D converter 22 (k-p-1), and the feedback path of the reception feedback port # 2 112 is illustrated to be input to the A / D converter 22k.

Accordingly, the number of antennas and the number of antenna ports of the radio unit 10 are the same as those of FIG. 3. When the antenna ports are grouped as described above, the modem 30 may generate and output reference signals to the respective antenna ports grouped at the same time. To this end, the present invention first corrects the average delay between the groups, and generates and outputs a transmission test signal. Orthogonal code for test signals to be transmitted to each port to transmit the same test signals at the same time point for phase correction corresponding to a path to each antenna port included in each group. Multiply by Therefore, the number of groups of antenna ports may be determined according to the number of codes having orthogonality with the number that can be processed at one time in response to transmission and reception of a test signal in the modem 30.

That is, the modem 30 may include the

antenna ports

11, 12,... Outputs a path of 1 (k-p-1) and multiplies the codes having orthogonality to each of the test signals to be fed back and outputs them simultaneously. Then each of the A /

D converters

221, 222,... , 22 (k-p-1) converts the test signals multiplied by the orthogonal code into an analog signal, and outputs the band up. Accordingly, the respective A /

D converters

221, 222,... , Transmit / receive switches corresponding to 22 (k-p-1) 211, 212,... , 21 (k-p-1) denotes the

respective antenna ports

11, 12,... , 1 (k-p-1) is set to be inputted and output.

Accordingly, each

antenna port

11, 12,... , 1 (k-p-1) outputs a signal to receive feedback port # 1 111. As previously described, each of the

antenna ports

11, 12,... Since all signals output as 1 (k-p-1) are output as multiplying orthogonal codes at the same time, the signals received at the reception feedback port # 1 111 are input at the same time. Accordingly, the reception feedback port # 1 111 corresponding to the first group may output the signal multiplied by the orthogonal code input at the same time to the A / D converter 22 (k-p-1) at one time.

Accordingly, the A / D converter 22 (k-p-1) converts the input signal to the band down and converts the analog signal into a digital signal and outputs the analog signal to the modem 30. The modem 30 may include transmission port

compensation signal calculators

501 and 502 corresponding to each group therein. Each of the transmission port

compensation signal calculators

501 and 502 included in the modem 30 may be implemented in a program form, in a logic form, or in a firmware form. Since the transmission port

compensation signal calculators

501 and 502 perform the same operation, only one operation will be described.

The transmission port compensation signal calculation unit # 1 501 performs the

antenna ports

11, 12,... , By receiving the test signals output as 1 (k-p-1) at once and multiplying each code again to remove each

port

11, 12,... , 1 (k-p-1) can be distinguished from the output signal. This makes it easy to detect the phase change along the transmission path of the test signal for each port.

The second group of antenna ports 1 (k-p), 1 (k-p + 1),... , 1k output signals may use the same code as the code of the first group, may be configured to transmit the signal at the same time, and the signal for the test of the second group after the signal of the first group is transmitted You can also configure to send them at once. The determination of this time point may be configured such that the test signal is transmitted with a predetermined time difference for each group according to the processing capability of the modem 30, or the test signal is simultaneously transmitted to each group.

Let's take a closer look at the orthogonal code here. The features required for orthogonal code are:

1) When accumulating by subbands, a sequence should be distinguishable for each antenna due to an orthogonal characteristic.

2) Orthogonal code that can be divided by the minimum number of antennas required for each subband is needed.

A sequence or code that satisfies the above code sequence characteristics and can be code-divided and used as a test signal includes a Zadoff-Chu sequence, a Walsh code, and a Hadarmad sequence. Also, using the above sequences or codes, a phase response for each antenna can be calculated as in Equation 1 below.

Equation 1

In <Equation 1>

Is a test signal corresponding to the k th frequency of the m th antenna among the test signals,

Is the phase response corresponding to the kth subcarrier of the mth antenna. Transmitted at the same time on each antenna

The sum of the antennas at the receiving end is a signal received through the k-th frequency is expressed as Equation (1).

In addition, the code sequence of Equation 1 is established according to the following Equation 2.

Equation 2

Accordingly, using Equation 1 and Equation 2, the response of the k th subcarrier of the m th antenna is

Can be calculated. Only the response of the kth subcarrier of the mth antenna

Since is a value calculated by the accumulation of subbands, the subcarriers of the number of tones (Ntone) are the same.

Should be applied. In other words, it is necessary to assume that the antenna phase characteristic is flat within the number of tones of subbands. Accordingly, it may be determined as in Equation 3 below.

Equation 3

Next, various methods of transmitting a test signal according to the form described above will be described. 6A and 6B are timing diagrams illustrating a case in which a test signal is transmitted for each group according to an exemplary embodiment of the present invention.

First, referring to FIG. 6A, a test signal is transmitted from a time point t0 to a time point t1 to all ports without division of the ports divided into groups. In this case, each test signal is multiplied by a code having different orthogonality in the group divided by port. That is, the test signal 601 outputted to the antenna port # 1 11 and the test signal 602 outputted to the antenna port # 2 12 are the same test signals, but codes having different orthogonalities are multiplied. Such code may use CDM code. In this case, the same codes may be used between groups. For example, an orthogonal code multiplied by a signal output to antenna port # 1 11 and an orthogonal code multiplied by antenna port # k-p 1 (k-p) may be the same code. That is, the orthogonal code can be reused for each group. 6A is a timing diagram illustrating a case in which a test signal is transmitted from antenna port # 1 11 to antenna port #k at once using FIG. 6A.

Next, referring to FIG. 6B, a time point at which a test signal is transmitted for each group is different. That is,

antenna ports

11, 12,... Each test signal output as 1k-p-1 is transmitted from the time point t0 to the time point t1. Again, the

respective test signals

601, 602,... 60k-p-1 is a signal multiplied by codes having different orthogonalities, for example, CDM codes may be multiplied. As described above, test signals may be transmitted and feedback with respect to the antenna ports of the first group, thereby checking the phase change for each path of each antenna port and performing compensation corresponding to each.

Thereafter, antenna port 1 (k-p), 1 (k-p + 1),... Which is the second group from the time t21 to the time t22. Each test signal output in 1k is transmitted. Again, the test signals 60k-p, 60k-p + 1,... 60k is a signal multiplied by codes having different orthogonalities, for example, CDM codes may be multiplied. In addition, since the first group and the second group are different groups, the same code may be used. For example, an orthogonal code multiplied by a signal output to antenna port # 1 11 and an orthogonal code multiplied by antenna port # k-p 1 (k-p) may be the same code. That is, the orthogonal code can be reused for each group.

After the test signal transmission and feedback processing is performed on the antenna ports of the first group, the test signal is transmitted and fed back to the antenna ports of the second group, and the phase change of each antenna port is examined. Compensation corresponding to may be performed. In the case of transmitting a signal as shown in FIG. 6B, only one receiving feedback port may be configured in FIG. 5. That is, it is possible to use only one receiving feedback port, and to configure the grouping for each antenna port to be the same, and to configure the test signal to be transmitted at different times for each group. An advantage of transmitting as in the case of FIG. 6B is that the present invention can be applied when it is difficult to additionally configure the feedback port in the radio unit 10. The physical configuration of FIG. 6B will be described later with reference to FIG. 8.

In the following description, the flowchart of FIG. 7 may be performed by the controller 40 or may be performed by the modem 30. Hereinafter, a description will be given of a case made in the modem 30 for convenience of description.

The modem 30 controls to set the feedback path of the test signal in step 700. That is, in Fig. 5, the transmit / receive

switches

211, 212,... , 21 (k-p-1), 21 (k-p), 21 (k-p + 1),... Set the 21k transmit / receive switch path to be the transmit path. In addition, the modem 30 controls the

antenna ports

11, 12, and 1 (kp-1) to be connected to the reception feedback port # 1 111 in step 700, and the antenna ports 1 (kp) and 1 (k- p + 1),... Up to 1k antenna ports perform switching to connect to receive feedback port # 2 112.

In step 710, the modem 30 compensates an average delay of antenna paths for each group between the transmit / receive switch and the radio unit 10. For example, if a delay between the feedback path to the reception feedback port # 1 111 and the feedback path to the reception feedback port # 2 112 is different, the corresponding value is compensated. For example, when the feedback path to the reception feedback port # 1 111 has a speed 0.1 ms faster than the feedback path to the reception feedback port # 2 112, the signal to the reception feedback port # 1 111 may be delayed by 0.1 ms and output. Alternatively, the delay time may be compensated for in the received signal. It is noted that step 710 is a step of recognizing a compensation value for each feedback path in advance.

After compensating for the delay of step 710, the modem 30 proceeds to step 720 and transmits a test signal multiplied by an orthogonal code to all antenna ports. That is, as illustrated in FIG. 6A, signals are transmitted to all ports, and the transmitted signals are output as multiplied by orthogonal codes or sequences as described above. Therefore, when a signal is transmitted in step 720, the A /

D converters

221, 222,... , 22 (k-p-1), 22 (k-p), 22 (k-p + 1),... , 22k and transmit / receive

switches

211, 212,... , 21 (k-p-1), 21 (k-p), 21 (k-p + 1),... Corresponding

antenna ports

11, 12,... , 1 (k-p-1), 1 (k-p), 1 (k-p + 1),... , 1k is outputted to corresponding receive

feedback ports

111 and 112. The feedback ports are fed back to modem 30 via the reconnected A / D converters 22 (k-p-1), 22k.

The modem 30 may be in a state where all signals are transmitted at the same time or time compensation is performed. If the time compensation is performed without performing the time compensation, the modem 30 performs the time compensation using the received signal. Then, the signal for each antenna port is separated from the signal received for each feedback port. This separation may use Equation 3 described above. After separating the signals, the modem 30 proceeds to step 740 to detect or calculate the phase change of each antenna port from the separated signals.

The modem 30 may detect a phase change for each antenna for each of the signals separated in operation 740, and generate a correction value of the transmission signal based on the phase change detected in operation 750.

The wireless part 10 of FIG. 8 has the same configuration as the case of FIG. 3 described above. In addition, the configuration of the switching and A / D converter 20 also has the same configuration as that of FIG. However, in FIG. 8, antennas, that is, antenna ports are grouped as shown in FIG. 5, and a signal is transmitted to the grouped antenna ports. Therefore, the test signal needs to be transmitted in time division for the antenna ports grouped as shown in FIG. 6B. Compensation for the antenna port for each group can be used as described in FIG.

In the case of FIG. 8, the process for compensating the path to each antenna takes more time than in the case of FIG. 5. However, in the case of Figure 8 is configured to have only one receiving feedback port, there is an advantage that can maintain the existing form as it does not change additionally to the configuration of the switching and A / D conversion unit 20.

9 illustrates a case in which reception feedback ports are included in each antenna port. Referring to FIG. 9, in the configuration of the wireless unit 10, a reception feedback port # 1 121 corresponding to the antenna port # 1 11 is connected, a reception feedback port # 2 122 corresponding to the antenna reception port # 2 12 is connected, and an antenna Receive feedback port #k 12k corresponding to port #k is connected. Thus, for each antenna port, the receiving

feedback ports

121, 122,... , 12k, and each of the

feedback ports

121, 122,... 12k denotes the corresponding antenna port and corresponding A /

D converters

221, 222,. Connect to return the signal to 22k.

Therefore, the modem 30 has transmission port

compensation signal calculators

901, 902,... Corresponding to each antenna port therein. , May include 90k. Also, the transmission port

compensation signal calculators

901, 902,... As described above, 90k may be configured as separate logic, program, or firmware.

9, since the feedback loop is configured for each antenna port, the load of the wireless unit 10 and the switching and A / D converter 20 may be increased in a large capacity multiple input / multi output antenna system. In addition, modem 30 may need to account for the delay of each transmission path for each antenna port, so additional calculations may be needed. The overall burden on the system increases.

However, the configuration as shown in FIG. 9 requires a code having an orthogonality since an additional operation such as multiplying a code or a sequence and removing the signal from a received signal is not required when generating a signal to test a transmission path. I never do that. In addition, when obtaining a response for each path, there is an advantage that the measurement can be performed for each subcarrier without accumulating in a subband manner.

Then, the advantages of each method described above will be summarized. In the case of applying the feedback method of the test signal for calibration in the large-capacity antenna system proposed in the present invention, the Tx calibration processing time that is linearly increased according to the number of antennas is divided according to the code group. This can be reduced by the number of groups or the number of feedback ports. In addition, in the case of the last embodiment, it is possible to detect and compensate for delay and phase change for each antenna port by quickly feeding back a test signal for compensation without additional time such as processing such an orthogonal code.

3, the transmission compensation process using the test signal according to the first embodiment (Fig. 5), the second embodiment (Fig. 8), and the third embodiment (Fig. 9) of the present invention. Comparing the time can be illustrated as shown in Table 1 below.

Table 1

	3	5	8	9
Processing time				τ
Path Response Estimation Unit	Subcarrier	Subband	Subband	Subcarrier

In the above table, for convenience, it is assumed that the compensation processing time is τ for each transmission path. Therefore, in FIG. 5, the generalized case is composed of L groups instead of two feedback loops. The total number of antennas is assumed to be NTx. As illustrated in Table 1, according to embodiments of the present invention, as shown in FIG. 3, there is an advantage in that the time required for calibration, which must be performed for each antenna port, can be reduced efficiently.

The embodiments disclosed in the specification and the drawings described above are merely presented specific examples to easily explain the contents of the present invention and help understanding thereof, and are not intended to limit the scope of the present invention. Therefore, the scope of the present invention should be construed that all changes or modifications derived based on the technical spirit of the present invention are included in the scope of the present invention in addition to the embodiments disclosed herein. For example, although various forms are illustrated in FIGS. 8A to 8I, all forms constituting the core with magnetic materials may not be illustrated, and various modifications may be made based on the same contents as those of the inventive concept. It is possible.

The present invention can be used in a large capacity antenna system.

Claims

In the phase correction method of the antenna in a large-capacity antenna system,

Grouping the large capacity antennas into a predetermined number of groups;

Establishing a path such that the grouped antenna ports have a feedback path;

Adding a code or sequence having orthogonality to test signals to be output to each antenna port of each group;

Separating a signal for each antenna port in the group using the orthogonal code or sequence from the signal received through the feedback path; And

And calculating a compensation value by detecting a phase change of the separated signal.
The method of claim 1,

Compensating the average delay calculated in advance for each group; Antenna phase correction method in a high-capacity antenna system.
The method of claim 1, wherein the orthogonal code or sequence is,

An antenna phase correction method in a large capacity antenna system, which is either Walsh code, Zadoff-Chu sequence or Hadarmad sequence.
The method of claim 3, wherein the number of groups is

And a method according to the orthogonal codes or the number of sequences.
The method of claim 1,

And outputting the test signal sequentially in the group unit when outputting by adding a code or a sequence having orthogonality.
The method of claim 1,

And outputting the test signals of all the grouped groups at the same time when the test signals are output by adding a code or sequence having orthogonality.
The method of claim 1, wherein the orthogonal code is:

Antenna phase correction method in a large capacity antenna system, which is reused for each group.
An apparatus for phase correction of an antenna in a large capacity antenna system,

A wireless unit including antenna ports corresponding to each of the antennas and including a feedback port grouped by the predetermined number of antennas;

A switching and A / D converter including transmission / reception switches corresponding to respective antenna ports of the radio unit and analog-to-digital converters corresponding to the transmission / reception switches; And

The path setting is controlled so that the grouped antenna ports have a feedback path, a test signal to be output to each antenna port of each group is generated, and a different code or sequence having orthogonality is added to each generated test signal and output. And a modem for separating a signal for each antenna port in a corresponding group by using a code or sequence having the orthogonality from the signal received through the feedback path, and detecting a phase change of the separated signal to calculate a compensation value; Including, the antenna phase correction device in a large-capacity antenna system.
The method of claim 8, wherein the modem,

And an antenna phase compensation device in a large capacity antenna system for compensating the average delay calculated in advance for each group.
The method of claim 8, wherein the orthogonal code or sequence is,

An antenna phase correction device in a large capacity antenna system, which is either Walsh code, Zadoff-Chu sequence, or Hadarmad sequence.
The method of claim 10, wherein the number of groups is

And a phase or number of sequences having codes that are orthogonal.
The method of claim 8, wherein the wireless unit,

Has one feedback port,

And the modem controls to output the test signal sequentially in the group unit when the test signal is added with an orthogonal code or sequence for each group.
The method of claim 8, wherein the wireless unit,

And outputting the test signal of all the grouped groups at the same time when the test signal is output by adding a code or sequence having orthogonality.
The method of claim 8, wherein the orthogonal code,

Antenna phase correction apparatus in a large capacity antenna system, which is reused for each group.
An apparatus for phase correction of an antenna in a large capacity antenna system,

A wireless unit including antenna ports corresponding to each antenna, and a feedback port corresponding to each antenna port;

Switching and A / D conversion including transmission / reception switches corresponding to respective antenna ports of the radio unit and analog-to-digital converters corresponding to the transmission / reception switches and receiving a signal output from the feedback ports. part; And

And a modem for generating and outputting a test signal to be output to each antenna port, and detecting a phase change from a signal received through each feedback path to calculate a compensation value.