KR102078616B1 - Method And Apparatus For Beam Interference Aware Automatic Gain Control and Beam Scheduling in Beamforming Communication Systmes - Google Patents

Abstract

Disclosed is an automatic gain control and beam scheduling method in consideration of beam interference in a beamforming communication system, and an apparatus therefor.
According to an aspect of the present embodiment, a base station having multiple antennas in a beamforming communication system, comprising: a communication unit that transmits and receives signals; And a control unit that collects interference information between a number of transmission beams and generates a beam combination list for transmission beam combinations that are not simultaneously transmitted based on the interference information, and controls to transmit them to a terminal.

Description

Method and Apparatus For Beam Interference Aware Automatic Gain Control and Beam Scheduling in Beamforming Communication Systmes in a beamforming communication system considering beam interference

The present disclosure relates to a method and apparatus for performing efficient automatic gain control in consideration of beam interference in an ultra-high frequency (mmWave) analog beamforming communication system, and performing beam scheduling to minimize beam interference.

The contents described in this section merely provide background information for this embodiment, and do not constitute a prior art.

The mmWave frequency band can utilize a broadband frequency of several GHz to support the rapid increase in mobile traffic. The standard specification for supporting the mmWave band is the IEEE 802.11ad (wireless gigabit alliance) standard in the 60Ghz frequency band, and various frequency candidate groups such as 15Ghz, 28GHz, 38GHz, 44GHz, and 70GHz for the next generation mobile 5G communication standard. About Samsung, Nokia, Ericsson, DoCoMo, Intel, and Qualcomm, companies are actively conducting research and development.

mmWave frequency band has a large path attenuation compared to the existing frequency band, but due to the short-wavelength characteristics of radio waves, a large number of array antennas are mounted in a given physical space and beamforming (BF) technology is applied to achieve high antenna gain and It is possible to secure a link budget required for wireless communication.

The network configuration of a typical mobile communication system is composed of an eNodeB (4G LTE), a gNodeB (5G) base station, and a user equipment (UE) terminal. The base station transmits a signal with a constant intensity, and the terminal receives a signal that has undergone a specific path attenuation according to its location. Generally, a terminal located close to receives a signal with a strong intensity, and a terminal located far away receives a signal with a weak intensity. Therefore, the signal strength coming into the terminal antenna has various distributions depending on the path attenuation according to the terminal location. Also, as the terminal moves, the received strength continuously varies.

1 is a view showing a structure of a receiving end of a receiving apparatus of a wireless communication system.

In general, the structure of the receiving end is shown in FIG. 1. The received signal from the antenna enters the ADC (Analog-To-Digital) through hardware blocks such as LNA, mixer, filter, and VGA.

The input signal of ADC hardware has dynamic range operation range. The dynamic range is determined in consideration of all matters when designing a system. Signal-to-noise ratio (SNR) required for modulation and decoding of a received signal, noise error in an ADC block, and peak-to-average of a signal (PAPR) Power Ratio), and considering the implementation margin in consideration of errors such as synchronization error, ADC dynamic range is set to a range that can accommodate them.

If the strength of the ADC input signal is not maintained at an appropriate level, the performance of the terminal is greatly deteriorated. For example, when the signal strength is greater than the dynamic range of the ADC, overflow occurs and the quality of the signal is greatly deteriorated. On the contrary, when the signal strength is too small, an error due to the digital quantization level of the ADC is caused. Therefore, the quality of the signal is also deteriorated. Therefore, it is important for the terminal to maintain the input signal of the ADC at an appropriate signal level (Reference Power) level through Automatic Gain Control (AGC).

1, automatic gain control refers to an operation of maintaining the input of the ADC at an appropriate level by measuring the strength of the ADC output signal and feeding it back to the VGA. As described above, the base station transmits a signal with a constant intensity, and the reception intensity of the signal varies depending on the position of the terminal. Therefore, in order to perform automatic gain control, the strength of the signal is measured from the currently received signal, and the VGA value is calculated and fed back so that the next incoming signal can be properly received within the dynamic range of the ADC.

In the 5G NR system using the mmWave frequency band, since the path attenuation is severe, the beamforming technique is used at the base station end, and the strength of the signal received by the terminal varies depending on the base station transmit beam direction. In order to guarantee signal quality in such a beamforming system, AGC must be able to be performed in response to a situation in which the strength of a signal received by a terminal is variable, and the base station efficiently performs beam scheduling to reduce interference between transmission beams. shall.

Embodiments of the present invention, in a beamforming communication system, when the transmission beam direction of the base station is variable, the terminal is mainly to provide a method and apparatus that can perform optimal automatic gain control for the ADC input signal of the receiving end There is a purpose.

In addition, embodiments of the present invention, in a beamforming communication system, the base station receives the beam feedback information about the signal reception strength from the terminal to provide a method and apparatus capable of performing beam scheduling to minimize interference between transmitted beams There is a purpose.

According to an aspect of the present embodiment, a communication unit for transmitting and receiving a signal in a base station having multiple antennas in a beamforming communication system; And a control unit that collects interference information between a plurality of transmission beams and generates a beam combination list for transmission beam combinations that are not simultaneously transmitted based on the interference information, and controls the transmission to be transmitted to a terminal.

The communication unit transmits signals for a plurality of transmission beams through a plurality of antennas, receives beam feedback information including reception intensity information of each transmission beam from a terminal, and the control unit is based on the beam feedback information The interference information may be collected by determining the degree of interference between a plurality of transmission beams.

According to an aspect of the present embodiment, a base station having multiple antennas in a beamforming communication system, comprising: a communication unit that transmits and receives signals; And a control unit for collecting interference information between a plurality of transmission beams of a serving base station and a neighboring base station, and generating a beam combination list for a transmission beam combination that is not transmitted simultaneously with the neighboring base station based on the interference information, and controlling the transmission to be transmitted to a terminal. It provides a base station comprising a.

According to an aspect of the present embodiment, a terminal in a beamforming communication system, comprising: a communication unit that receives reference signals for a plurality of transmission beams from a base station; And a control unit that individually measures the reception intensity of each transmission beam from the reference signal to calculate a maximum reception intensity for a combination of transmission beams that the terminal can receive, and performs automatic gain control using the maximum reception intensity. Terminal.

The control unit may calculate the maximum reception strength by summing the number of antenna ports of the base station in the order in which the strength of each transmission beam is strong.

The control unit may control to receive a beam combination list that is not simultaneously transmitted from the base station, and may calculate the maximum reception strength by referring to the beam combination list that is not simultaneously transmitted.

According to an aspect of the present embodiment, a terminal of a beamforming communication system includes: a communication unit that receives reference signals for a plurality of transmission beams from a serving base station and an adjacent base station; And a control unit that individually measures the reception intensity of each transmission beam from the reference signal to calculate a maximum reception intensity for a combination of transmission beams that the terminal can receive, and performs automatic gain control using the maximum reception intensity. Terminal.

According to an aspect of the present embodiment, in a method of operating a base station having multiple antennas in a beamforming communication system, the serving base station simultaneously with the neighbor base station based on interference information between a plurality of transmission beams of the serving base station and the neighbor base station Generating a beam combination list that is not transmitted; A process in which the serving base station and a neighboring base station share the beam combination list; Receiving beam scheduling information of a neighboring base station from the neighboring base station; It provides a method comprising the step of performing a beam scheduling by referring to the beam combination list and the beam scheduling information of the neighboring base station in the serving base station.

According to an aspect of the present embodiment, in a beamforming communication system, a method of operating a base station having multiple antennas includes: transmitting reference signals for a plurality of transmission beams through a plurality of antennas; Receiving beam feedback information including reception intensity information of each transmission beam from a terminal; It provides a method comprising determining a transmission beam combination having high interference based on the beam feedback information and generating a constraint beam combination list based on the frequency of occurrence of the transmission beam combination according to the location of the terminal.

The method may further include performing beam scheduling to minimize interference between transmission beams transmitted by the base station with reference to the constraint beam combination list.

According to an aspect of the present embodiment, in a beamforming communication system, a method of operating a base station having multiple antennas includes: transmitting reference signals for a plurality of transmission beams through a plurality of antennas; Receiving beam feedback information including reception intensity information of each transmission beam from a plurality of terminals in a serving cell; It provides a method including performing a beam scheduling to minimize interference between a plurality of transmission beams based on the beam feedback information received for each of the plurality of terminals.

According to an aspect of the present embodiment, in a beamforming communication system, a method of operating a base station having multiple antennas includes: transmitting reference signals for a plurality of transmission beams through a plurality of antennas; Receiving beam feedback information including reception intensity information of each transmission beam from a terminal; Provides a method comprising determining a modulation and coding scheme (MCS) level by calculating a signal-to-noise interference ratio (SINR) value of a terminal according to interference information between multiple transmission beams based on the beam feedback information do.

As described above, according to embodiments of the present invention, by transmitting information on a beam combination simultaneously transmitted by the base station to the terminal, the terminal can efficiently perform automatic gain control, thereby increasing the reception performance of the terminal. It has an effect.

In addition, according to embodiments of the present invention, the base station can receive information on a transmission beam combination in which interference between each other is largely received by receiving reception strength information from a terminal, and inter-beam interference information is continuously updated to effect inter-beam interference The diagram can be analyzed and managed, and the system can be operated to minimize inter-beam interference by referring to it during beam scheduling.

In addition, according to embodiments of the present invention, the base station itself can be implemented to perform a SON (Self-Organized Network) operation to analyze the interference effect between the beams from the information reported by the terminal, to operate to minimize the impact of the beam interference It works.

1 is a view showing a structure of a receiving end of a receiving apparatus of a wireless communication system.
2 is a view showing the configuration of an internal resource unit according to whether or not to use a resource block of the LTE / LTE-Advanced system.
3 is a diagram illustrating signal transmission of a base station in a 4G LTE / LTE-Advanced system.
FIG. 4 is a diagram illustrating beamforming signal transmission of a base station in a 5G NR mmWave communication system.
5 is a view showing a change in reception strength at a terminal according to a transmission beam of a base station in a 5G NR mmWave communication system.
6 is a diagram illustrating a set of transmit beam shapes of a 5G base station antenna.
7 is a diagram illustrating a change in the terminal reception strength according to the base station beam transmission.
8 is a diagram illustrating a method of setting a BRS transmission period and a logical beam index of a Pre-5G standard.
9 is a diagram illustrating a logical beam index mapping method of the Pre-5G standard.
10 is a diagram illustrating a method of transmitting a beam sweep of a BRS signal of Pre-5G standard.
11 is a flowchart illustrating a signal processing process in a terminal for measuring a BRSRP by a terminal receiving a BRS signal from a base station according to an embodiment of the present invention.
12 is a diagram showing a resource configuration of a BRS signal section.
13 is a flowchart illustrating a process of performing beam scheduling using an RBS table in a base station according to an embodiment of the present invention.
14 is a flowchart illustrating a process of performing automatic gain control using BRSRP information in a terminal according to an embodiment of the present invention.
15 is a diagram illustrating an example of describing RBS transmission constraints at the ASN level according to an embodiment of the present invention.
16 shows the configuration of a base station in a beamforming communication system according to the present embodiment.
17 shows the configuration of a terminal in a beamforming communication system according to the present embodiment.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. It should be noted that in adding reference numerals to the components of each drawing, the same components have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing the present invention, when it is determined that detailed descriptions of related well-known configurations or functions may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, or order of the component is not limited by the term. Throughout the specification, when a part is 'included' or 'equipped' a component, this means that other components may be further included rather than excluded, unless specifically stated to the contrary. . In addition, '… Terms such as "unit" and "module" mean a unit that processes at least one function or operation, and may be implemented by hardware or software or a combination of hardware and software.

DETAILED DESCRIPTION The detailed description set forth below, in conjunction with the accompanying drawings, is intended to describe exemplary embodiments of the invention, and is not intended to represent the only embodiments in which the invention may be practiced.

In describing the embodiments of the present disclosure in detail, a multi-input multiple-output (MIMO) system supporting ultra-high frequency (mmWave) band and beamforming will be mainly targeted, but the present disclosure is intended to be claimed. The main subject matter is applicable to other communication systems and services having a similar technical background without departing greatly from the scope disclosed herein.

In a beamforming system, a base station may transmit data while changing a direction of a downlink transmission beam using a plurality of array antennas for each cell. Also, the terminal can receive data while changing the reception beam direction. In a beamforming communication system, a base station and a terminal provide a data service by selecting a direction of a transmission beam and a direction of a reception beam that show an optimal channel environment among various transmission beam directions and reception beam directions. This process applies equally to a downlink channel transmitting data from a base station to a terminal as well as an uplink channel transmitting data from a terminal to a base station.

In an embodiment of the present invention, a base station or a cell generally refers to a point communicating with a user terminal, and the terminal selects a base station having the strongest signal strength among neighboring base stations as a serving base station in a multiple base station situation. Control signals and data are transmitted and received through the serving base station. In addition, the terminal may classify other neighbor base stations as scheduling candidate base stations and change the serving base station according to the channel condition.

2 is a view showing the configuration of an internal resource unit according to whether or not to use a resource block of the LTE / LTE-Advanced system.

3 is a diagram illustrating signal transmission of a base station in a 4G LTE / LTE-Advanced system.

Hereinafter, a method of measuring a reception strength of an input signal by a terminal in an existing 4G LTE / LTE-Advanced system will be described with reference to FIGS. 2 and 3, and a method of performing automatic gain control based on the method will be described. do.

In the LTE / LTE-Advanced system, radio resources transmitted by a base station to a terminal are divided into resource block (RB) units on a frequency axis and subframes (hereinafter, can be used in combination with subframes) on a time axis. Lose. In performing the scheduling, the LTE / LTE-Advanced system may allocate resources in units of subframes on the time axis and resources in units of resource blocks on the frequency axis.

That is, since the LTE / LTE-Advanced signal can determine whether or not the signal is transmitted in the resource block unit in the frequency domain by the OFDM transmission method, the strength of the signal received by the terminal is continuously changed even if there is no physical environment change in the system. . Therefore, it is impossible to determine the VGA value for the received signal of the next subframe based on only the received signal strength indication (RSSI) of the current subframe, and thus a stable AGC operation is impossible. For example, when the usage of the resource block in subframe # 1 is 30% and the usage of the resource block in subframe # 2 is 80%, the AGC is calculated by calculating the VGA value based on the RSSI in subframe # 1. If performed, overflow may occur in subframe # 2.

Referring to FIG. 2, a resource block, which is a minimum unit for allocating resources, is composed of 12 subcarriers in the frequency domain, and the subframe is 14 OFDM symbols in the time domain (hereinafter, it can be used in combination with symbols). It consists of sections and has a total of 168 natural frequencies and time locations. Each natural frequency and time location in FIG. 2 is called a resource unit (RE), and one subframe consists of two slots each consisting of seven OFDM symbols.

In a 4G LTE / LTE-Advanced system, AGC is performed using a cell-specific reference signal (CRS) signal that is always transmitted even if a resource block is not used as shown in FIG. 2. Referring to FIG. 2, since the CRS RE is always transmitted regardless of whether or not the resource block is used (in both Full RB and Empty RB situations in FIG. 2), the reception strength of the CRS signal is independent of the resource block utilization of the subframe. It is always constant. Accordingly, it is assumed that all resource blocks are used using the signal strength of the CRS signal existing in the subframe, and then the VGA value is calculated and applied to the next subframe.

Specifically, the UE can know the CRS reception location from the Cell ID (PSS, SSS), the number of antenna ports (Physical Downlink Control Channel (PDCCH) blind decoding), and the Physical Downlink Shared Channel (PDSCH) from Secondary Information Broadcasting (SIB) The signal strength of CRS RE compared to RE can be seen. From the received strength of the RE used for the CRS, the received signal strength corresponding to the maximum RB usage rate can be obtained regardless of the actual RB usage rate. Since the UE cannot know in advance how much the base station will use the RB, the AGC can be stably performed by always performing the AGC in preparation for the case of transmitting using the RB at the maximum.

In addition, in a multi-base station situation, all of the RE positions in which the CRSs are transmitted are accumulated, and the AGC operation may be performed in a case where the received signals transmitted from all the base stations are combined and entered.

Since the 4G LTE system transmits the omni-antenna as shown in FIG. 3, the UE receives a signal of a continuous strength without significantly changing the reception strength of the CRS signal for each subframe. Therefore, as described above, when the gain required for the terminal is calculated from the CRS signal strength information obtained in the previous previous subframe period and applied to the next subframe period, a stable AGC operation can be performed.

FIG. 4 is a diagram illustrating beamforming signal transmission of a base station in a 5G NR mmWave communication system.

5 is a view showing a change in reception strength at a terminal according to a transmission beam of a base station in a 5G NR mmWave communication system.

Hereinafter, a 5G NR mmWave communication system will be described with reference to FIGS. 4 and 5. In FIG. 4, in a single base station situation, three UEs # 1 (10), UE # 2 (20), and UE # 3 (30) according to subframes (over time) are Tx beam # 2 and Tx, respectively. It shows a case in which Beam # 10 and Tx Beam # 4 are received. 5 shows a change in the reception strength of a signal based on UE # 1.

Since the ultra-high frequency mmWave band has severe path attenuation, a beamforming technique is used at the base station end (or even at the terminal end) to overcome this. Therefore, the base station transmits a beam in a specific direction every moment as shown in FIG. 4. For simplicity, the base station is assumed to have one single beam, and the currently discussed Pre-5G standard supports up to eight beams.

As a result, the signal strength received by the terminal varies according to the base station transmit beam direction as shown in FIG. 5. In addition, the beam direction may be changed in a symbol unit for each channel even in the same subframe. For simplicity, the PDCCH and PDSCH transmissions show the same situation. In the currently discussed 5G standard, a self-contained structure of TDD (Time-Division Duplexing) method is assumed (downlink and uplink can coexist in one subframe), but here, for convenience of description, a subframe that only transmits downlink The structure is shown.

In this way, since the beam transmission situation changes each time, in 5G system, it is not possible to perform AGC in all subframes as in the 4G LTE system, and the terminal is actually transmitted, that is, the base station transmission beam transmitting in its own direction For this, AGC should be performed from the received signal by setting the optimal reception beam.

In addition, since 5G can determine whether or not the RB is transmitted, such as OFDM transmission of 4G LTE, AGC must be performed using a signal section capable of predicting signal strength for the case of using the entire RB. However, since the 5G standard aims to minimize the always-on signal, there is no signal that is always transmitted in every subframe like the CRS of 4G LTE. Accordingly, in the embodiments of the present invention, in order to perform AGC, a signal capable of measuring reception strength for all RBs of a specific beam is a BRS (Beam Reference Signal), a BR-RS (Beam Refinement Reference Signal), or a CSI-RS. (Channel State Indicator Reference Signal) proposes a method using a signal.

6 is a diagram illustrating a set of transmit beam shapes of a 5G base station antenna. Hereinafter, a situation in which interference between transmission beams occurs in a 5G NR mmWave communication system will be described with reference to FIG. 6.

The shape of the transmission beam of the 5G base station is not completely isolated and transmitted only in a specific direction when actually implemented, and has a shape of a sync waveform having a main lobe in a specific direction and an additional side lobe sideways. . The base station can transmit the beam by twisting the beam in a specific direction by adjusting the phase of the antenna element.

Since the base station must be able to support all users in the coverage with such a beam shape (sync waveform), a plurality of predefined transmission beam sets are selected and transmitted. 6 shows all of the base station transmission beam sets. As shown in the figure, the beams are not orthogonal to each other, and the main lobes of the beams are overlapped at a considerable intensity. As such, the reason why the beam set is closely packed so that the main lobes between the beams overlap each other at a sufficient intensity is that the terminal has a minimum level of reduction (-3dB display) compared to the maximum signal strength (0dB display) even if the terminal is located anywhere around the base station. This is to enable this signal to be received. That is, as shown in FIG. 6, when the beams are densely overlapped and the terminal always selects and receives the optimal transmission beam from the duplex, the signal can be received at a level of reduction within 3dB compared to the maximum reception strength regardless of the direction in which the terminal is located. have.

Referring to FIG. 6, it can be seen that in addition to the main lobe interference, there is also beam interference caused by side lobes between adjacent beams. That is, it can be seen that beam interference occurs to affect each other between all beams, and also occurs at a large intensity that cannot be ignored.

7 is a diagram illustrating a change in the terminal reception strength according to the base station beam transmission. 7A illustrates a situation in which beam transmission is simultaneously performed to UE # 1 (10) and UE # 3 (30), and FIG. 7B is beam transmission to UE # 1 (10) and UE # 2 (20) at the same time. The situation is illustrated. 7C illustrates a situation in which beam transmission is simultaneously performed to UE # 1 (10), UE # 2 (20), UE # 3 (30), and UE # 4 (40).

As described above, the 5G NR system changes the beam configuration at each base station for each subframe. In this case, due to inter-beam interference, the strength of the signal received by the terminal is not constant but varies. For example, referring to FIG. 7, UE # 1 10 has a signal strength difference of approximately 3 dB in the case of FIGS. 7A and 7B.

7A is a situation in which UE # 1 (10) is transmitted by a single beam (Beam # 2) alone, and FIG. 7B shows UE # 2 (20) in an adjacent beam (Beam # 1) and UE # in the base station. This is a situation in which 1 (10) and UE # 2 (20) are transmitted within the same subframe. In this case, if UE # 1 (10) is located in the boundary area of Beam # 1 and Beam # 2, the strength received by the UE has a difference of 3 dB.

Accordingly, when the UE # 1 10 performs AGC by simply considering the beam (Beam # 2) it receives, as shown in FIG. 7A, when the situation of FIG. 7B occurs, the intensity is doubled (3dB). When a signal is received, overflow occurs in the ADC block, and as a result, decoding performance is greatly deteriorated.

In the current Pre-5G standard, the base station is defined to have up to 8 beams. Therefore, when simulating the maximum signal strength received by the UE for any 8 beam combinations selected by the base station, it occurs in a situation where the UE # 1 (10) is located at the position where the main lobe of the 8 beams overlaps as shown in FIG. 7C. Is done. Since the terminal can support up to 2 x 2 MIMO, it is assumed that two beams are transmitted in the same direction. In this case, compared to the intensity of the beam (Beam # 2) actually used by the terminal UE # 1 (10), a signal of an intensity added by 9 dB is received. This corresponds to 1.5 bit based on ADC ENOB.

Also, if not only the transmission beams of a single base station but also the transmission beams of a plurality of base stations are considered, the inter-beam interference becomes greater.

In the above, the simple LOS (Line-Of-Sight) environment has been described, and if the NLOS (Non-Line-Of-Sight) environment without a main signal is considered, the inter-beam interference situation becomes much more complicated and greater intensity Interference may occur.

In order to solve this problem, it is possible to consider a method in which a base station transmits a combination of transmission beams to a terminal in advance, so that the terminal updates an appropriate VGA in consideration of inter-beam interference each time. However, this method generates a very large control signal overhead, and also has a problem of limiting the scheduling of the base station to the terminal delivery time.

Therefore, in this embodiment, in order to eliminate the need for excessive securing of the dynamic range of the terminal caused by inter-beam interference in 5G NR and enable efficient hardware design, to define the mutual promise between the base station and the terminal for the beam transmission combination do. In addition, in 5G requirements, it is desired to maximize spectrum efficiency and ensure a transmission rate of a certain level or higher in a border area such as a cell edge, and for this, beam scheduling is performed to reduce beam interference between intra-eNB or inter-eNB. Need a way. In this embodiment, a method of scheduling a beam to minimize the impact of the beam interference is proposed by continuously updating the beam interference information from a beam measurement report transmitted by the UE.

As described above, in 5G, the terminal may vary the strength of the received signal according to the base station transmit beam direction and RB usage rate. Therefore, it is necessary to use a signal capable of measuring the entire RB channel for the optimal beam of the terminal. In the Pre-5G standard, such signals may include BRS, BR-RS, and CSI-RS signals. Hereinafter, a BRS signal periodically transmitted to perform a beam search to the UE will be described as an example.

The base station and the terminal may select and transmit some beams suitable for communication among a plurality of beams. For such beam selection, in a beamforming-based mobile communication system, a base station may transmit a BRS that is a beamformed reference signal at regular time intervals or whenever necessary. The BRS is a reference signal transmitted for each beam of the base station.

In this way, the base station may transmit the BRS through all or some beams, and the terminal may receive it through all or some beams and generate beam measurement information using the BRS. In this case, the beam measurement information may refer to a result of measuring the reference signal when the reference signal transmitted through the beam of the base station is received through the beam of the terminal. In this embodiment, the reference signal transmitted through the beam It can be expressed as measuring the beam.

For example, the beam measurement information may include signal strength or signal quality of the beam transmitted by the base station. By generating beam measurement information using the reference signal in this way, the UE can determine which beam is best communicated when the base station transmits data to it and which beam it receives. In addition, since the terminal informs the base station of the beam measurement information, the base station can select a beam to be used when communicating with the terminal.

In addition, if the UE determines that the beam of the neighboring base station provides a higher signal strength or quality than the beam of the serving base station after measuring the BRS, it can inform the base station. The base station receiving the information may perform an operation for handing over the terminal to a neighboring base station. In addition, after measuring the BRS transmitted by the serving base station and neighboring base stations, the terminal may form a group of base stations having a received signal strength of a certain level or higher and inform the base station. Upon receiving communication with the terminal, the base station may perform transmission and reception by selecting one of a plurality of base stations belonging to the base station meeting.

In addition, after the UE measures the BRS, if it is determined that the beam pair in use and the other beam pair provide higher signal strength or quality, the UE may select another beam pair to transmit and receive data.

8 is a diagram illustrating a method of setting a BRS transmission period and a logical beam index of a Pre-5G standard.

9 is a diagram illustrating a logical beam index mapping method of the Pre-5G standard.

In the current Pre-5G standard, the transmission period of a synchronization signal (PSS) including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), an extended synchronization signal (ESS), and a BRS is 5 ms (1 slot), as shown in FIG. 8. It can be repeatedly transmitted every 5 ms (1 subframe), 10 ms (2 subframe), and 20 ms (4 subframe), and thus can simultaneously transmit beams at P antenna ports using 7, 14, 28, and 56 symbols, respectively.

Specifically, when one subframe is 0.2 ms and the radio frame is 10 ms, the transmission period of the BRS can be set as shown in FIG. 8. Referring to FIG. 8, four configurations are defined in the Pre-5G standard, and a case in which the base station performs beam sweeping for all BRSs during 1 slot, 1 subframe, 2subframes, and 4 subframes is illustrated. In this embodiment, it is assumed that one subframe consists of 2 slots and 1 slot consists of 7 OFDM symbols. When the beam sweeping is set to 1 slot and the base station has one antenna, the beam is changed and transmitted for every 7 symbols corresponding to one slot, indicating that the signal is transmitted in a total of 7 beams. If the base station has P antennas and the corresponding P antennas are simultaneously transmitted in each OFDM symbol, it means sweeping 7 * P beams based on 1 slot. In FIG. 8, the period of the BRS is indicated by 2 bits, and the corresponding signal is signaled by a higher layer. It includes a method in which the corresponding 2 bits are indicated in the MIB transmitted through the LTE-based PBCH. 8 is an example of setting for a BRS indication bit, a corresponding BRS transmission period, and a maximum number of beams that can be sweeped by a base station corresponding to each transmission period and a logical beam index.

9 shows an example in which a logical beam index is mapped by an OFDM symbol index and an antenna port index. It is assumed that the system allocates a subframe that transmits BRS in units of 5 ms. In this case, when the BRS transmission period is 1 slot, 2 beam sweeping is performed within one BRS subframe. When the BRS transmission period is 1 subframe, 1 beam sweeping is performed within one BRS subframe. When the BRS transmission period is 2 subframes, 1 beam sweeping is performed during 2 BRS subframes for 10 ms. When the BRS transmission period is 4 subframes, 1 beam sweeping is performed during 4 BRS subframes for 20 ms.

In FIG. 9, the meaning of the BRS transmission region means a BRS subframe in 5 ms units and is an example of a mapping formula of logical beam index according to each OFDM symbol (ie index i) and antenna port index (ie index p) in each subframe. N ^DL _symb means the number of OFDM symbols in one slot, and the corresponding value based on LTE is 7.

10 is a diagram illustrating a method of transmitting a beam sweep of a BRS signal of Pre-5G standard.

In FIG. 10, a transmission period is 10 ms (2 subframes), and a case in which four antenna ports of the base station are shown is shown, in which case BRS for up to 112 beams may be transmitted. The terminal receives the BRS signal with the transmission beam of the base station overlapped. Here, a maximum of 8 orthogonal cover codes (OCCs) are transmitted between the signals of the antenna ports, so that if the channels in the RB are constant, they can be orthogonally separated from each other.

In addition, the beam strength measured by the UE can report to the base station BAM (Beam State Information, BSI = BI (Beam Index) + BRSRP (Beam Reference Signal Received Power)) for one optimal candidate beam as a PUCCH signal, The PUSCH signal is defined to report BSI up to 4 candidate beams.

In this embodiment, the case of using the BRS signal is exemplarily described, but it is also possible to obtain channel information for the beam by using signals such as BR-RS and CSI-RS.

The UE can measure the signal strength with respect to the desired transmission beam direction using the BRS signal. However, since the beam signals of the antenna ports overlap each other in the BRS signal, it is impossible to know the exact beam strength by simply adding the received strength. For example, referring to FIG. 10, when the optimal beam of the terminal is the first beam, the signals of the 15th, 29th, and 43th beams are simultaneously received with the corresponding BRS signal, and the reception strengths of the 4 beams are measured.

In addition, as described above, even in a PDSCH signal section in which actual data is transmitted, up to 8 beams may be overlapped and transmitted in one base station, so the reception strength of a section in which BRS is transmitted and the signal strength in a section in which PDSCH is transmitted are single base station. The difference can be up to 9dB with only the signal.

11 is a flowchart illustrating a signal processing process in a terminal for measuring a BRSRP by a terminal receiving a BRS signal from a base station according to an embodiment of the present invention.

12 is a diagram showing a resource configuration of a BRS signal section.

Hereinafter, a process of calculating the BRSRP value of the BRS signal in the beam search process will be described with reference to FIGS. 11 and 12.

The terminal receives a signal by setting in its optimal receive beam direction according to its optimal transmission beam transmission timing in the BRS section, and extracts a BRS signal section from the received signal (S1101). The FFT (Fast Fourier Transform) is performed on the extracted signal to transform it into a frequency domain signal (S1102), and a BRS signal band is extracted (S1103). Since the base station transmits multiple transmission beams through multiple antennas at the same time, the antenna-specific (intra-gNB) BRS signal is separated through orthogonal cover code (OCC) decoding (S1104).

Referring to FIG. 12, in the time period in which the BRS signal is received, there are frequency sections other than the BRS signal, such as PSS, SSS, and ESS signals, in addition to the BRS signal. Therefore, the correlation is calculated through cross-correlation between the BRS signals at this time (S1105), and the entire interval signal is obtained by inferring the empty sections (PSS, SSS, and ESS sections) through interpolation (S1106). Inverse Fast Fourier Transform (IFFT) is performed on the entire interval signal obtained through the process S1106 to convert it into a time domain signal (S1107). In an inter-gNB situation in a multi-cell environment, denoising is performed to remove the influence of signal sequences of adjacent cells (S1108).

The signal strength in the thus obtained BRS section is accumulated (S1109), the VGA setting of the receiving end is compensated (S1110), and the BRSRP for the corresponding base station beam is measured (S1111). The measured BRSRP is used to perform automatic gain control at the terminal.

11, in steps S1105 to S1106, the strength of the PSS, SSS, and ESS sections is inferred through interpolation, but a method for inferring the ratio of the received strength compared to the received strength obtained in the BRS signal section (total received signal strength = BRS) It is also possible to use a received signal x (100 PRBs / 82 PRBs). However, it is possible to obtain a more accurate numerical value by inferring a corresponding section using an interpolation method.

Hereinafter, a method of performing automatic gain control by updating a user's own VGA value using the BRSRP value of the BRS signal calculated in the beam search process by the terminal will be described.

In this embodiment, it is assumed that the base station forms B _tx beams and selects all or part of them to communicate with the terminal. In addition, it is assumed that the terminal forms B _rx beams and selects all or part of them to communicate with the base station. Therefore, between the base station and the terminal, there are a total of B _tx * B _rx beam pairs composed of a beam of the base station and a beam of the terminal, and the terminal measures the strength of the BRS reception signal for the B _tx * B _rx beam pairs to receive the signal. Select the best beam pair in terms of strength.

In this embodiment, the BRS transmitted by the base station may not be transmitted every subframe like CRS of LTE, but may be transmitted only in periodically allocated subframes. For example, the base station may transmit BRS in one subframe included in one radio frame. Alternatively, the base station may transmit BRS in a plurality of subframes included in one radio frame.

In addition, since the base station can transmit BRS through one beam in symbol (or multiple symbol) units, it is possible to transmit BRS for multiple beams in one subframe. Therefore, in order to measure all signal strengths for B _tx * B _rx beam pairs, the UE performs measurement for several subframes according to B _tx, B _rx , number of symbols per subframe, and the like.

In FIG. 10, a subframe in which the BRS is transmitted, a BRS subframe, a period in which the BRS subframe is allocated, a BRS period, and a time required for the UE to measure all B _tx * B _rx beam pairs are referred to as a full sweep period. You can. A full sweep period is a time required for a base station and a terminal to measure all beam pairs through beam sweeping, and may be referred to as a full beam measurement period. Referring to FIG. 10, the BRS period is 5 ms and the full sweep period is 10 ms.

In this embodiment, a case in which the base station transmits the BRS while sweeping the transmission beam and the terminal receives the BRS transmitted by the base station in a state where it is fixed to the reception beam in its optimal direction will be described as an example. The beam sweep may mean an operation of transmitting a reference signal while changing a beam and an operation of changing a beam and receiving a reference signal.

In this embodiment, the case where the terminal receives each of the BRS transmitted by the base station using one beam in two BRS subframes within a full sweep period has been described as an example, but the present invention is not limited thereto. For example, the base station may transmit a BRS while sweeping a beam in a plurality of BRS subframes, and the terminal may receive a BRS using a beam in a plurality of BRS subframes.

Through this method, the UE can measure all BRS signal strengths for B _tx * B _rx beam pairs during a full sweep period.

First, in the context of a single base station, the UE sets its own optimal receive beam direction (ie, sets it as the receive beam direction in the PDSCH section), and measures the reception strength for each beam to determine the combination of transmit beams that the UE can receive. Calculate the maximum reception strength for. The maximum reception strength is calculated by arranging the reception strengths for individual beams in descending order, and summing up the number of antenna ports of the serving cell in the order of the strongest strength. The terminal may perform automatic gain control using the calculated maximum reception strength. The formula is as follows.

는 단말 수신 beam을 b^rx로 기지국 송신 beam을 b^tx로 설정하여 얻어진 BRSRP를 의미하며, b^rx ₀, b^rx ₁, … ,b^rx _Brx 및 b^tx ₀, b^tx ₁, … , b^tx _Btx 의 beam 순서는 수신 beam을 선순위로 설정하고, BRSRP 세기에 대한 내림차 순으로 정렬되어 있다.

가 가장 큰 세기를 가지는 송수신 beam 조합 b^rx ₀ 및 b^tx ₀ 전송시의 BRSRP며,

는 수신 beam을 b^rx ₀로 고정한 상황에서 BRSRP가 두 번째로 가장 센 경우의 송신 beam, 즉 b^tx ₁ 송신 beam 전송 시의 BRSRP를 의미한다.Here, P ^rx _max means the size of the maximum received power that the terminal can receive from a single base station. A _tx means the number of base station transmit antenna ports (array antenna group transmitting in a specific beam direction).

BRSRP obtained by setting the terminal reception beam to b ^rx and the base station transmission beam to b ^tx , b ^rx ₀ , b ^rx ₁ ,. , b ^rx _Brx and b ^tx ₀ , b ^tx ₁ ,… , b ^tx The beam order of _Btx sets the received beam as a priority, and is arranged in descending order of BRSRP intensity.

Is a BRSRP when transmitting / receiving beam combinations b ^rx ₀ and b ^tx ₀ having the greatest intensity,

Is a transmission beam when the BRSRP is the second strongest in the situation in which the received beam is fixed to b ^rx ₀ , that is, the BRSRP when transmitting the b ^tx ₁ transmission beam.

The terminal updates the automatic gain control using the maximum reception strength P ^rx _max . The automatic gain control is performed by additionally taking into account the influence of PAPR, channel fading, implementation margin, etc. on the corresponding maximum received signal strength, which can be fixedly or variably taken through various experiments.

That is, since the number of transmit beams that can be simultaneously transmitted by a single base station is the same as the number of antenna ports A _tx , a maximum of A _tx beams can be simultaneously received by the terminal. Stable signal reception is possible only when automatic gain control is performed in consideration of the case where interference between beams received by the terminal is most severe. Therefore, the UE measures BRSRP for all beams received during the full sweep period, and then calculates the maximum receive strength P ^rx _max that can be received by accumulating as many antenna ports as the BRSRP strength is strong. Gain control to be applied to the full sweep period is performed.

The same method can be applied to multiple base stations. In this embodiment, the UE periodically measures the BRS signal transmitted by the neighboring base station to support mobility. If the automatic gain control of the terminal is performed, including the beam transmitted by the adjacent base station, it can be expressed as follows.

는 C번째 기지국에서 단말 수신 beam을 b^rx, 기지국 송신 beam을 b^tx로 설정했을 경우의 BRSRP를 나타낸다. 이와 같은 방법으로 단말은 다중 기지국 환경에서도 정상적인 자동 이득 제어 레벨을 유지할 수 있게 된다. A _tx means the number of transmit antenna ports of the base station. Here, C represents the total number of base stations received by the terminal,

Denotes BRSRP when the UE reception beam is set to b ^rx and the base station transmission beam is set to b ^tx in the C-th base station. In this way, the terminal can maintain a normal automatic gain control level even in a multi-base station environment.

That is, in a multiple base station situation, beams are simultaneously transmitted from multiple base stations, and the number of transmit beams transmitted simultaneously at the same time is equal to the sum of the number of antenna ports A _{j and tx} corresponding to a single base station, so that the maximum A _{1 for the} terminal. _{, tx} + A _{2, tx} +… + A _{C, tx} beams can be simultaneously received. Similarly, since automatic gain control is performed in consideration of the case where the inter-beam interference received by the terminal is most severe, stable signal reception is possible, so the terminal measures BRSRP for all transmission beams received from all base stations during a full sweep period. , Calculate the maximum receive strength P ^rx _max that can be received by accumulating the number of antenna ports of multiple base stations from the strong BRSRP strength, and perform automatic gain control using this number.

As described above, the terminal performs automatic gain control on the assumption that the interference between beams received by the terminal is the most severe, considering the number of transmit beams that can be simultaneously transmitted by the base station. Here, when the base station determines that the beam combinations for which the inter-beam interference is predicted to be high are not transmitted at the same time, and when the beam combinations determined to not transmit at the same time are notified in advance, the maximum reception strength value predicted by the terminal is lowered. , Automatic gain control margin can be minimized. As a result, the dynamic range is widened to optimize reception performance at the terminal.

For example, referring to FIG. 7B, interference between beams is very high in UE # 1 10 located at the boundary between beam # 1 and beam # 2. Therefore, the base station determines that it does not transmit simultaneously for a combination (beam # 1, beam # 2) having high interference between beams in consideration of beam interference of its antenna port, and transmits it to the terminal in advance. The terminal calculates the maximum reception strength except when the beam combination (beam # 1, beam # 2) is received. That is, since the case in which the UE simultaneously receives the beam combination will not occur, in the process of calculating the maximum reception strength, the case of summing the BRSRP strength for beam # 1 and the BRSRP strength for beam # 2 is automatically excluded. It is possible to minimize the gain control margin.

Since the UE measures the BRSRP strength for the entire BRS in the current full sweep period and performs gain control in the next period, the base station can notify the UE by transmitting every beam combination that is not simultaneously transmitted every period.

In this embodiment, when the terminal notifies the list of beam combinations that are not simultaneously transmitted by the base station, it may correspond to a case in which the LTE cell associated with the high frequency base station directly informs the terminal (Non-standalone) or SIB ( This may also be the case when individual information is transmitted to all terminals in the serving cell through a System Information Block (RSB) signal or to specific terminals in a serving cell through a Radio Resource Control (RRC) signal (Standalone).

In this embodiment, a simple line-of-sight (LOS) environment is described as an example, but in a real situation in which multiple base stations or NLOS (Non Line-of-Sight) environments or RF repeaters and optical repeaters are additionally transmitted. It can be extended. For example, when it is predicted that the interference between a transmission beam of an adjacent base station and its own beam is high in a multiple base station, it may be determined that the adjacent base station does not transmit simultaneously with the corresponding beam and may notify the UE in advance.

Hereinafter, a method of predicting a beam combination having high interference with respect to a beam transmitted by the base station will be described. In this embodiment, for this purpose, a method of using beam measurement information, such as beam status information (BSI) or beam refinement information (BRI), which the UE periodically or non-periodically transmits to the serving cell base station, is proposed. do.

In the case of the Verizon 5G standard, when the terminal receives the BRS signal from the base station, the beam strength measured by the terminal is defined to report the BSI information (BI + BRSRP) for the four optimal candidate beams to the base station as a PUSCH signal. have. This is originally intended to have 4 candidate beams to be transmitted from the base station to the UE, but in other words, the strength of the BRSRP is high for the corresponding beams at the location of the UE, and interference between the 4 candidate beams can be considered to be large. You can.

The base station receives the BRSRP information for the beam from the terminal, and based on this, determines a combination of transmission beams predicted to have high interference. Based on the location of a terminal or a frequency in which a corresponding transmission beam combination occurs in a cell, if high interference between corresponding beams frequently occurs, it may be determined as a beam combination that does not transmit simultaneously.

In addition, the base station receives BRSRP information for a beam from multiple terminals located in a serving cell, accumulates BRSRP intensity according to a combination of transmit beams, and statistically analyzes the accumulated collected intensity information to transmit beams with high interference. Combinations can be judged. The base station continuously collects inter-beam interference information measured at a specific terminal for a plurality of terminals through such statistical analysis, so that inter-transmission beam interference occurs for a plurality of transmission beams owned by the base station rather than information at a specific time point. Information can be judged.

In addition, the base station not only notifies the corresponding beam combination to the terminal, but can also manage itself by adding it to its restricted beam combination RBS (Restricted Beam Set) list. Here, the RBS list is based on information reported from the terminal in a cell in its serving cell, and may be continuously updated whenever information is received from the terminal. This is information unique to the base station, and the base station can perform beam scheduling so that interference between beams is minimized by referring to this.

In addition, the RBS list may be managed as a separate list according to beam shape information of the terminal and dynamic range information that the terminal can accommodate. When the terminal initially raises information such as the number of received beams or the received beam width of the received terminal to the base station, the base station can operate with a separate RBS table to match the characteristics of the terminal based on this. In this case, such information may enable transmission of specific RBS information to a corresponding terminal at an RRC level when a terminal having a similar reception beam is subsequently accessed.

13 is a flowchart illustrating a process of performing beam scheduling using an RBS table in a base station according to an embodiment of the present invention. Hereinafter, a process of performing beam scheduling using an RBS table at a base station will be described using a multi-base station situation (including one serving base station and one neighboring base station) as an example.

First, a BRS signal is transmitted from a serving base station and an adjacent base station located in the vicinity of the terminal (S1301, S1302), and the terminal receives the BRS signal (S1303). The terminal measures the BRSRP strength for the transmission beam transmitted from the serving base station and the adjacent base station based on the received BRS signal (S1304).

The terminal transmits beam measurement information such as beam status information (BSI) or beam refinement information (BRI) including BRSRP strength for a plurality of transmission beams to the serving base station (S1305). In the case of the Verizon 5G standard, the beam strength measured by the terminal reports BSI information (BI + BRSRP) for the four optimal candidate beams to the base station as a PUSCH signal.

The base station receives the beam measurement information from the terminal (S1306), receives the BRSRP information for the beam, and analyzes the interference effect between beams based on this (S1307). Here, the BRSRP information may include information on a transmission beam of an adjacent base station. The base station determines a transmission beam combination predicted to have high interference based on BRSRP information on the beam received from the terminal, and if the frequency of occurrence of the transmission beam combination in the location or cell of the terminal is high, the interference effect between the beams is also affected. It can be analyzed that is high.

The inter-beam interference is compared with a set threshold (S1308), and when it is determined that the inter-beam interference is high, the corresponding beam combination is added to the RBS (Restricted Beam Set) table of its own constraint beam combination (S1309). When the RBS table information includes the beam of the neighboring base station, the RBS information is transmitted to the neighboring base station (S1310). The neighbor base station receives this RBS information and adds it to its RBS table (S1311).

The neighboring base station and the serving base station share beam scheduling information (S1312, S1313) and perform beam scheduling so that the beam combination included in the RBS table is excluded (S1314). If the combination of high beam interference determined based on the information reported by the terminal includes a beam of an adjacent base station, information on beam interference between base stations can be shared with each other through signals between base stations such as X2 interface connection in steps S1312 and S1313. . In step S1314, when scheduling a beam, resources are shared with each other in a real-time or time-sharing manner, and accordingly, from a system point of view, interference effects occurring in a transmission space can be reduced according to beam setting, and as a result, overall performance can be improved.

Since the RBS table includes a beam combination having high inter-beam interference, beam scheduling is performed by excluding this, so that the serving base station can transmit data with minimal beam interference (S1315), and the effect of inter-beam interference at the terminal It is possible to receive data in a minimized state (S1316).

In the present embodiment, by setting the transmission beam to exclude the list of beam combinations having high interference during beam scheduling, the terminal can receive data in a state in which interference between beams is not large. As described above, when the transmission effect is reduced by reducing the interference effect between beams generated in the transmission space, there is an effect of increasing the transmission capacity of the base station. Further, according to the present embodiment, a self-organized network (SON) operation in which a base station configures an entire network by controlling interference between beams by itself is enabled from beam information transmitted by a terminal.

In particular, since PDSCH transmission uses high-order modulation such as 16-QAM, 64-QAM, and 256-QAM, it is necessary to obtain the maximum performance of the ADC stage in order to secure the EVM of the entire received signal. Therefore, the maximum reception performance can be obtained by limiting the transmission beam combination using the RBS list as in the present embodiment.

However, in order to transmit a control signal such as a PDCCH to transmit a signal such as UL HARQ ACK / NACK, information of several subframes can be collected and transmitted, and reducing a beam combination to be transmitted in the same way as PDSCH transmission is a relatively large limitation. You can. In this case, since the PDCCH signal is transmitted as a BPSK or QPSK signal, a reference level of a received signal is lowered in a PDCCH section at a terminal receiving unit (back-off a certain level at a reference level of a PDSCH), or a base station transmits a lowered signal strength. You can. In addition, for this purpose, the base station may manage the PDCCH interval as a separate RBS table by lowering the threshold condition of the inter-beam interference intensity.

14 is a flowchart illustrating a process of performing automatic gain control using BRSRP information in a terminal according to an embodiment of the present invention. Hereinafter, a method in which the terminal performs automatic gain control from the perspective of the entire system will be described in detail with reference to FIG. 14.

First, the serving base station transmits necessary system information for the terminal to access the network through a PBCH (Physical Broadcast Channel) (S1401). The PBCH includes system information such as a downlink system bandwidth and a system frame number (SFN). The terminal checks the number of antenna ports of the base station through the information received through the PBCH (S1402). At this time, the number of antenna ports may not be explicitly included in the system information, and the terminal may check the number of antenna ports by blind detection.

The serving base station transmits the SIB to the terminal on which the control channel is formed (S1403). The SIB transmitted by the serving base station may include RBS information of the serving base station. SIB is common control information that is commonly applied to a terminal in a serving cell, and the RBS information included therein corresponds to information unique to a base station that does not take into account the reception beam characteristics of the terminal. The terminal receives the RBS information broadcast by the SIB from the serving base station, and receives RBS information of the serving base station and the adjacent base station (S1405).

Thereafter, the base station can optimize the RBS information in consideration of the characteristics of the terminal. Specifically, the terminal may transmit the shape of the terminal receiving antenna to the serving base station during initial connection (S1405). The base station may receive this information (S1406) and operate a separate RBS optimized for the terminal in consideration of the received beam characteristics of the terminal. The base station may transmit user-dedicated RBS information optimized according to the shape of the receiving antenna to the terminal (S1407). The terminal receives the user-dedicated RBS information (S1408), and the base station grasps in advance the beam combination excluded when scheduling the beam to itself (the terminal). That is, when the terminal initially raises information such as the number of received beams or the received beam width of the received terminal to the base station, the base station can operate a separate RBS table optimized for the characteristics of the terminal based on this. In this case, such information may enable transmission of specific RBS information to a corresponding terminal at an RRC level when a terminal having a similar reception beam is subsequently accessed.

When BRSs for a plurality of beams are transmitted from a serving base station and an adjacent base station (S1409, S1410), the UE receives a BRS signal (S1411) and measures BRSRP for multiple beams (S1402). In a multi-base station situation, beams are simultaneously transmitted from multiple base stations, and a terminal can simultaneously receive a beam of a total number of antenna ports of all nearby base stations. Therefore, the UE calculates all BRSRP accumulation values for possible beam combinations in the neighbor base stations (the number of beams in the combination is equal to the number of antenna ports of the neighbor base stations) (S1413). Among the BRSRP accumulated values calculated in S1413, the largest BRSRP accumulated value is secured (S1413), except for cases corresponding to the RBSP beam combination transmitted by the UE through S1405 and S1409 (S1413). The accumulated BRSRP value obtained in step S1415 is the maximum received strength for a combination of transmit beams that can be received by the terminal, and automatic gain control is performed using this (S1416).

15 is a diagram illustrating an example of describing RBS transmission constraints at the ASN level according to an embodiment of the present invention.

In addition, if the processing performance of the base station is sufficient, it is also possible to operate the proposed scheduling method for reducing beam interference from real-time BSI information of the user. That is, when the base station continuously updates and manages BSI information for each terminal periodically reported, when selecting a terminal to be simultaneously transmitted during data transmission, the scheduling may be determined to minimize inter-beam interference by referring to BRSRP values between corresponding transmission beam combinations in real time. In addition, the signal-to-noise interference ratio (SINR) value experienced by the UE can be predicted from the BRSRP value of the UE for the corresponding beam combination to determine the MCS level transmitted to the UE (its beam direction is signal strength, other beam The direction corresponds to the interference intensity).

According to this embodiment, it can be summarized in a way that the base station system restricts such a situation so that a situation in which the inter-beam interference felt by the terminal does not occur after cell planning. In the proposed method, in addition to the AGC operation of the terminal, since the space is divided from the perspective of the entire system and the beam transmission is selected in the direction of less interference, as a result, the capacity is increased from the perspective of the overall system.

For the convenience of explanation, the proposed method has been described based on the Verizon 5G standard, and can be modified and applied according to the detailed specifications of the 3GPP NR to be determined.

16 shows the configuration of a base station in a beamforming communication system according to the present embodiment.

Referring to FIG. 16, the base station according to the present embodiment includes a communication unit 1610 and a control unit 1620.

The communication unit 1610 transmits signals such as reference signals and data to the terminal and receives data and channel feedback information from the terminal. Specifically, the communication unit 160 may transmit signals for a plurality of transmission beams through a plurality of antennas to the terminal, and receive beam feedback information including reception intensity information of each transmission beam from the terminal.

The control unit 1620 may control the communication unit 1610 to transmit signals for a plurality of transmission beams and receive beam feedback information from the terminal. The controller 1620 may determine a degree of interference between a plurality of transmission beams based on the received beam feedback information, and may generate a beam combination list by determining a combination of transmission beams that are not simultaneously transmitted according to the degree of interference. The generated beam combination list can be controlled to be transmitted to the terminal.

In addition, when receiving beam feedback information for a transmission beam of an adjacent base station from a terminal in a multi-base station situation, the controller 1620 determines the degree of interference with a transmission beam of an adjacent base station based on the received beam feedback information, and the adjacent A list of transmission beam combinations that are not transmitted simultaneously with the base station can be generated and controlled to be transmitted to the terminal.

In addition, when the beam combination list is transmitted from the control unit 1620 to the terminal, it may correspond to a case in which the LTE cell associated with the high frequency base station directly informs the terminal (Non-standalone), and transmits a System Information Block (SIB) signal. This may also be the case when transmitting to all terminals in the serving cell or transmitting individual information to a specific terminal in the serving cell through a Radio Resource Control (RRC) signal (Standalone).

17 shows the configuration of a terminal in a beamforming communication system according to the present embodiment.

Referring to FIG. 17, the terminal according to the present embodiment includes a communication unit 1710 and a control unit 1720.

The communication unit 1710 receives signals such as reference signals and data transmitted from the base station and transmits them to the control unit 1720.

The control unit 1720 may check beam information from received signals received from the communication unit 1710, receive a reference signal, generate beam feedback information according to the reference signal, and use another reference signal to decode data. It can be done. The beam feedback information may be reported to the base station through the communication unit 1710.

In addition, the control unit 1720 individually measures the reception intensity of each transmission beam from the reference signal received from the base station, and calculates the maximum reception intensity possible in the combination of transmission beams that the terminal can receive, thereby automatically controlling the gain of the ADC input. You can do

In addition, the controller 1720 may control to transmit beam feedback information for a transmission beam of an adjacent base station to a generating serving base station based on a reference signal received from a neighbor base station as well as a serving base station in a multiple base station situation, and input an ADC. In order to perform automatic gain control for, it is possible to consider the reception strength of a transmission beam of an adjacent base station.

In addition, when the control unit 1720 receives a transmission beam combination that the base station does not transmit simultaneously or a transmission beam combination that does not transmit simultaneously with an adjacent base station, the control unit 1720 refers to the maximum reception strength possible in the transmission beam combination that the terminal can receive. Can be calculated.

11, 13, and 14 are described as sequentially executing each process, this is merely illustrative of the technical idea of an embodiment of the present invention. In other words, those of ordinary skill in the art to which one embodiment of the present invention pertains may perform or change the order described in FIGS. 11, 13, and 14 without departing from the essential characteristics of one embodiment of the present invention, or Since one or more of the processes may be applied in various modifications and variations by executing one or more processes in parallel, FIG. 10 is not limited to the time series order.

Meanwhile, each step of the flowcharts shown in FIGS. 11, 13, and 14 can be implemented as computer-readable codes on a computer-readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data readable by a computer system is stored. That is, the computer readable recording medium includes magnetic storage media (eg, ROM, floppy disk, hard disk, etc.), optical reading media (eg, CD-ROM, DVD, etc.) and carrier waves (eg, the Internet). Storage). The computer-readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

The above description is merely illustrative of the technical spirit of the present embodiment, and those skilled in the art to which this embodiment belongs may be able to make various modifications and variations without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical spirit of the present embodiment, but to explain, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The protection scope of the present embodiment should be interpreted by the claims below, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present embodiment.

10: UE # 1
20: UE # 2
30: UE # 3

Claims (27)

In a base station having multiple antennas in a beamforming communication system,
A communication unit that transmits and receives signals; And
Interference information between a plurality of transmission beams is collected based on a measurement report of at least one terminal for a plurality of transmission beams, and a beam combination list for transmission beam combinations that are not transmitted at the same time is generated based on the interference information. Control unit that controls to transmit to one terminal
Base station comprising a. According to claim 1,
The communication unit,
Signals for a plurality of transmission beams are transmitted through a plurality of antennas, beam feedback information including reception intensity information of each transmission beam is received from a terminal,
The control unit,
A base station characterized by determining the degree of interference between a plurality of transmission beams based on the beam feedback information and collecting the interference information. According to claim 2,
The control unit,
A base station characterized by accumulating beam feedback information received from a plurality of terminals in a serving cell and collecting the interference information by statistically analyzing the degree of interference between the plurality of transmission beams. In a base station having multiple antennas in a beamforming communication system,
A communication unit that transmits and receives signals; And
A combination of transmission beams that collect interference information between multiple transmission beams of the base station and an adjacent base station based on the measurement report of at least one terminal for multiple transmission beams, and do not transmit simultaneously with the adjacent base station based on the interference information Control unit for generating a beam combination list for the control to transmit to the at least one terminal
Base station comprising a. The method of claim 4,
The communication unit,
A signal for a plurality of transmission beams is transmitted through a plurality of antennas, and beam feedback information including reception intensity information of each transmission beam of the adjacent base station is received from a terminal,
The control unit,
A base station characterized by determining the degree of interference between a plurality of transmission beams based on the beam feedback information and collecting the interference information. The method of claim 5,
The control unit,
A base station characterized by accumulating beam feedback information received from a plurality of terminals in a serving cell and collecting the interference information by statistically analyzing the degree of interference between the plurality of transmission beams. The method of claim 1 or 4,
The control unit,
In the case of NSA (Non-Standalone), a base station characterized in that the beam combination list is controlled to be transmitted through a 4G LTE cell. The method of claim 1 or 4,
The control unit,
In the case of a standalone (SA) method, the base station is characterized in that the beam combination list is controlled to be transmitted to all terminals in a serving cell through a System Information Block (SIB). The method of claim 1 or 4,
The control unit,
In the case of a standalone (SA) method, the base station is characterized in that the beam combination list is controlled to be individually transmitted to a terminal in a serving cell through a radio resource control (RRC) signal. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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