KR102522781B1 - Method and apparatus for relay based on multiple beams in vehicle-to-everything communication system - Google Patents

Abstract

A method of operating a relay operating in the same band full-duplex method includes measuring a signal received from a source node during a first interval; measuring a signal received from the source node and a signal received after being transmitted through a first beam from the relay during a second interval after a predetermined delay time from the first interval; and comparing a measurement result during the second period with a measurement result during the first period, and calculating an amount of self-interference of the first beam.

Description

Method and apparatus for relay based on multiple beams in V2X communication system {Method and apparatus for relay based on multiple beams in vehicle-to-everything communication system}

The present invention relates to a mobile relay in a vehicle wireless communication system, and more particularly, to a mobile relay operating method and mobile relay device for V2X communication.

Vehicle wireless communication technology, expressed as V2X (vehicle to everything), is a communication technology that supports various vehicle-related communication services such as vehicle safety, autonomous driving, in-vehicle entertainment, and group driving. In 3GPP, a new 5G NR (new radio) V2X standardization based on the completed 5G NR (new radio) Rel-15 standard is in progress, and a terminal that enables vehicle communication outside the network service area to meet the service requirements required by 5G Sidelink, which is an inter-communication method, was introduced to NR.

In 5G mobile communication technology, a millimeter wave frequency band that is easy to secure a broadband frequency bandwidth to meet eMBB (enhanced Mobile BroadBand) service requirements to support high-capacity transmission speeds of several Gbps, such as large-capacity file transmission and high-definition video service supports Unlike the existing sub-6 GHz band called 'sub-6 GHz', the mmWave band is a frequency band of 30 to 300 GHz and is characterized by having a wavelength in mm. In 5G NR, a frequency band of 6 GHz or higher is defined as FR (frequency range) 2 and the 'above-6 GHz' standard is established in order to increase communication channel capacity by using the wideband bandwidth of the millimeter wave frequency band that has not yet been allocated. Due to its short wavelength, millimeter wave has the disadvantage of experiencing higher path loss than low-frequency band communication below 6 GHz. can do. Therefore, in millimeter wave communication, a multi-antenna beamforming technique having high directivity is adopted as a technique for overcoming path loss.

In an existing mobile communication system, a relay uses a time division multiplexing (TDD) method in which transmission and reception sections are separated in time to avoid self-interference (SI) that occurs when signals are transmitted and received in the same band at the same time. ) has been mainly considered. Self-interference refers to interference in which a self-transmitted signal is reflected from a same-band full-duplex transceiver and flows into a self-receiver. Existing communication systems adopt a half duplex (HD) method that is less efficient in frequency than the same-band full-duplex method but is easy to control interference. Therefore, simultaneous transmission and reception of signals is not possible in the time division relay. For example, in the case of an LTE-based relay, the relay cannot transmit any signal including a control signal through a communication link between terminals during a period in which the relay receives a signal from a backhaul link. Accordingly, the relay receives a signal from the base station only in a multimedia broadcast single frequency network (MBSFN) subframe interval having a transmission gap, and transmits a PDCCH to the terminal in a specific OFDM symbol interval. Therefore, in relays operating in half-duplex mode, the time delay from the base station to the transmission of signals to the final terminal through the relay is very large, and the timing alignment to separate the transmission and reception sections in time is elaborated to prevent transmission and reception signals from interfering with each other. It must be controlled. In addition, since many time slots cannot be allocated for relaying while temporally separated, there is a disadvantage in that limited data can only be relayed.

An object of the present invention to solve the above problems is to provide a method of operating a multi-beam based relay operating in an in-band full duplex (IFD) method. Another object of the present invention to solve the above problems is to provide a multi-beam based relay operating in an IFD method.

An embodiment of the present invention for achieving the above object is a method of operating a relay operating in an IFD method, comprising: measuring a signal received from a source node during a first interval; measuring a signal received from the source node and a signal received after being transmitted through a first beam from the relay during a second interval after a predetermined delay time from the first interval; and comparing a measurement result during the second period with a measurement result during the first period, and calculating an amount of self-interference of the first beam.

The predetermined delay time may be a delay time for a relaying operation of the relay.

The predetermined delay time may be a time obtained by adding a predetermined additional delay time to a delay time for a relaying operation of the relay.

In the first period and the second period, an automatic gain control (AGC) value of the relay may be set to be the same.

Signals measured in the first interval and the second interval may be a synchronization signal, a short training format (STF) preamble, or a long training format (LTF) preamble.

The relay, the source node, and the destination node may operate in a beam-sweeping method.

The operation method may further include determining to perform a relay operation for the source node when the amount of self-interference of the first beam is less than a predetermined threshold.

When there are N transmission beams in the relay, the amount of self-interference of L transmission beams among the N transmission beams is smaller than the predetermined threshold value, and the amount of self-interference of the i-th beam among the L transmission beams is i-1th. If the self-interference amount of the beam is smaller than the self-interference amount of the beam, the relay may perform a relay operation for the source node using the i-th beam.

When N transmission beams exist in the relay, the relay may perform a relay operation for the source node using a transmission beam having the smallest amount of self-interference among the N transmission beams.

An embodiment of the present invention for achieving the above other object is a relay operating in an IFD method, comprising: an analog beam forming unit connected to a transmitting antenna and a receiving antenna; an RF converter for converting a baseband signal into an RF band signal or converting an RF band signal into a baseband signal, and controlling a gain of a received signal; a beam measuring unit measuring a signal received from a source node and a signal received after being transmitted from the relay through the first beam; and a beam manager for controlling operations of the analog beamformer, the RF converter, and the beam measurer, wherein the beam manager measures a signal received from a source node using the beam measurer for a first period and ; A signal received from the source node and a signal received from the relay are transmitted through the first beam during a second interval after a predetermined delay time after the first interval by using the analog beamforming unit and the beam measuring unit measure the signal; It may be set to calculate the amount of self-interference of the first beam by comparing the measurement result during the second interval with the measurement result during the first interval.

The predetermined delay time may be a delay time for a relaying operation of the relay.

The predetermined delay time may be a time obtained by adding a predetermined additional delay time to a delay time for a relaying operation of the relay.

In the first period and the second period, the beam management unit may set an automatic gain control (AGC) value of the RF conversion unit to be the same.

Signals measured in the first interval and the second interval may be a synchronization signal, a short training format (STF) preamble, or a long training format (LTF) preamble.

The relay, the source node, and the destination node may operate in a beam-sweeping method.

When the amount of self-interference of the first beam is less than a predetermined threshold, the beam management unit may determine to perform a relay operation for the source node.

When the analog beamformer forms N transmission beams, the self-interference amount of L transmission beams among the N transmission beams is less than the predetermined threshold value, and the self-interference amount of the ith beam among the L transmission beams is i- If the amount of self-interference is smaller than the amount of self-interference of the 1st beam, the beam management unit may determine to perform a relay operation for the source node using the i-th beam.

When the analog beamforming unit forms N transmission beams, the beam management unit may determine to perform a relay operation for the source node using a transmission beam having the smallest amount of self-interference among the N transmission beams.

By using an embodiment of the present invention, a signal blocking phenomenon and a shadow area frequently caused by obstacles in a network of a vehicle wireless communication system can be eliminated. The relay according to the embodiment of the present invention can relay data with a shorter time delay than conventional time-division relays, and performs simultaneous transmission and reception without separating a separate data reception section and transmission section for the relay. It is possible to expand the amount of data to be relayed or the relay time slot. In addition, the multi-beam-based full-duplex relay transceiver according to the present invention has an effect of reducing the burden of an analog/digital self-interference cancellation (SIC) operation of an existing full-duplex communication device.

1 is a conceptual diagram of a vehicle wireless communication system using a millimeter wave band.
2 is a conceptual diagram for explaining the operation of a multi-beam based IFD type relay to which embodiments of the present invention are applied.
3 is a flowchart illustrating a method of operating an IFD-type relay according to an embodiment of the present invention.
4 is a conceptual diagram illustrating an example of setting a measurement interval for measuring self-interference in an IFD-type relay according to an embodiment of the present invention.
5 is a conceptual diagram illustrating another example of setting a measurement interval for measuring self-interference in an IFD-type relay according to an embodiment of the present invention.
6 is a conceptual diagram for explaining an operating region of each relay according to an operating method of an IFD-type relay according to an embodiment of the present invention.
7 is a block diagram for explaining the structure of an IFD-type relay according to an embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals have been used for like elements throughout the description of each figure.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The term “and/or” includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate overall understanding in the description of the present invention, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

An embodiment of the present invention relates to a vehicle wireless relay for extending a service area by resolving a shadow area formed due to signal blocking by an obstacle in a V2X wireless communication network and transmitting a signal to a vehicle or terminal outside the network. Hereinafter, an embodiment of the present invention is described by taking a relay in cellular communication-based V2X communication as an example, but the embodiment of the present invention can be equally applied to various wireless communication systems to which the relay system can be applied.

1 is a conceptual diagram of a vehicle wireless communication system using a millimeter wave band.

Referring to FIG. 1 , in a vehicle wireless communication system, communication such as vehicle-to-vehicle (V2V) communication, vehicle-to-pedestrian (V2P) communication, and vehicle-to-infrastructure entity (V2I) communication may be performed. V2V communication may refer to communication between vehicles, V2P communication may refer to communication between a vehicle and a device owned by a pedestrian, and V2I communication may refer to communication between a vehicle and a road side unit (RSU) installed on a road. .

Meanwhile, in a vehicle communication environment, a movement of a vehicle terminal may frequently change due to a vehicle lane change or driving on a curved road. In addition, in the case of a vehicle wireless communication system using a millimeter wave band, signal disconnection due to unexpected LOS (line-of-sight) signal blocking due to vehicle movement and surrounding objects (surrounding vehicles or surrounding structures) may occur. In order to solve this problem, a relay is considered very important in a mmWave band based vehicle wireless communication system.

The relay may extend network coverage and improve network throughput by relaying a signal to a network boundary area or a terminal outside the network. In addition, the relay can solve the shadow area in the network. In addition, the relay can effectively restore a communication link by relaying a signal when a millimeter wave signal is blocked due to a surrounding obstacle that frequently occurs in a vehicle communication system.

In an existing mobile communication system, a relay uses a time division multiplexing method (time division multiplexing, TDD) has been mainly considered. Self-interference refers to interference caused by a signal transmitted by a transceiver of the same band full duplex (IFD) method flowing into its own receiver. Existing communication systems are of the same band full duplex method. It adopts half-duplex multiplexing, which is less efficient in frequency but easier to control interference, therefore, simultaneous transmission and reception of signals is not possible in time-division relays For example, based on 3GPP LTE (long-term evolution) The relay cannot transmit any signals, including control signals, through the communication link between the relay and the terminal while receiving signals from the backhaul link. Signals are received from the base station only in the subframe interval and PDCCH is transmitted to the terminal in a specific OFDM symbol interval Therefore, in the case of a relay operating in half-duplex multiplexing, there is a time delay until the base station transmits the signal to the final terminal through the relay. This is very large, and sophisticated timing alignment control is required to separate the transmission and reception sections in time so that the transmission and reception signals do not interfere with each other. There is a disadvantage that only capacity data is relayed.

2 is a conceptual diagram for explaining an operation of a multi-beam based full-duplex relay to which embodiments of the present invention are applied.

Referring to FIG. 2 , in one embodiment of the present invention, each relay may operate in an IFD manner. In addition, each of the source node, the relay, and the destination node may sequentially transmit multiple beams according to a predetermined pattern in a beam sweeping method. In this case, each relay (eg, relays #1 to #N) receives a signal transmitted from a source node in the n-th time slot and simultaneously transmits a signal to a destination node. Relay discovery may be performed through, and data may be transmitted in the n+1 th time slot through the selected relay. In addition, the IFD-type relay may simultaneously perform relay search and data transmission in the n-th time slot by configuring a signal such as a training symbol. Embodiments according to the present invention can be applied to both the former case and the latter case.

The IFD-type relays shown in FIG. 2 have a problem of self-interference (SI) in which a signal transmitted by itself flows into a receiver. An embodiment of the present invention proposes a multi-beam management method for controlling the SI of the above-described IFD-type relay. A communication system using millimeter waves is advantageous in integrating a plurality of antennas in a transceiver, improves link performance through transmission and reception beam matching, and has the advantage of being able to control interference through beam avoidance. .

라 하고,

번째 릴레이가 송신하는 신호와

번째 릴레이에서 수신되는 신호를 각각

와

라 하고, 소스 노드와 릴레이 사이에 형성된 링크를

이라 하면

번째 릴레이의 수신 신호는 하기 수학식 1과 같이 표현될 수 있다. Referring to FIG. 2, the signal transmitted from the source node to the relays in the nth time slot

say,

The signal transmitted by the second relay and

signal received from the second relay

and

, and the link formed between the source node and the relay

If you say

The received signal of the second relay may be expressed as in Equation 1 below.

,

는 각각 소스 노드의 송신 파워와 소스와 릴레이 사이의 채널 성분에 해당한다. 상기 수학식 1에서 두번째 항은

번째 릴레이에서 수신되는 자기 간섭(SI) 성분이며,

번째 릴레이의 송신 파워와 채널 성분

으로 표현될 수 있다. 이 때 송수신 신호에 다중 빔이 적용되면 수학식 1의 채널 성분

,

은 빔포밍 이득과 각도가 적용된 채널 성분

및

로 하기 수학식 2와 같이 표현될 수 있다. in Equation 1

,

Corresponds to the transmit power of the source node and the channel component between the source and relay, respectively. The second term in Equation 1 is

It is a magnetic interference (SI) component received from the th relay,

Transmission power and channel components of the second relay

can be expressed as At this time, if multiple beams are applied to the transmission and reception signals, the channel component of Equation 1

,

Channel component with applied beamforming gain and angle

and

It can be expressed as in Equation 2 below.

Meanwhile, the signal received by the destination node through the IFD-type relay in the n-th time slot of FIG. 2 may be expressed as in Equation 3 below.

와

는 각각 릴레이와 목적지 노드 간의 채널 성분과 소스 노드와 목적지 노드 간의 채널 성분에 해당한다. 이 때 다중 빔이 적용된 목적지의 수신 신호의 채널 성분

와

는 하기 수학식 4와 같이 표현될 수 있다. in Equation 3

and

Corresponds to a channel component between the relay and the destination node and a channel component between the source node and the destination node, respectively. At this time, the channel component of the received signal of the destination to which multi-beams are applied

and

Can be expressed as in Equation 4 below.

과 릴레이에서 목적지 노드로 수신되는 신호

의 수신 성능을 높이기 위해 간섭 신호의 크기를 최소화할 수 있는 소스 노드, 릴레이, 목적지 노드의 송수신 빔을 선택하는 방법 및 IFD 방식 릴레이 장치의 구조가 설명된다.As described above, it can be seen that in the IFD-type relay, the magnitude of self-interference varies depending on the beam used between the source node and the relay node and the beam used between the relay and the destination node. Therefore, below, the signal received from the source node to the relay in the IFD type relay

and the signal received from the relay to the destination node

A method for selecting transmission/reception beams of a source node, a relay, and a destination node capable of minimizing the size of an interference signal in order to increase reception performance of a signal and a structure of an IFD-type relay device are described.

3 is a flowchart illustrating a method of operating an IFD-type relay according to an embodiment of the present invention.

Referring to FIG. 3, when a link is established between a source node and a relay through beamforming, an IFD-type relay (hereinafter referred to as a relay) according to an embodiment of the present invention measures a signal received from the source node during a first period. It can be done (S310). In addition, during a second period after a predetermined delay time after the first period, the relay may measure a signal received from the source node and a signal received after being transmitted through the first beam from the relay. (S320). In this case, the first period is a period in which a signal received from the source node exists, and the second period is a period in which the signal received from the source node and the relay are transmitted through the first beam from the transmitter of the relay. This is the section where the signal introduced into the receiver exists together. Meanwhile, a predetermined delay time may exist between the first section of step S310 and the second section of step S320.

4 is a conceptual diagram illustrating an example of setting a measurement interval for measuring self-interference in an IFD-type relay according to an embodiment of the present invention, and FIG. It is a conceptual diagram illustrating another example of setting a measurement interval for measuring interference.

Referring to FIG. 4, in the case of a typical relay, a predetermined delay is generated to process a signal received from a source node and transmit the processed signal to a destination node. In the case of a relay operating in an amplify-and-forward (AF) method, the predetermined delay time may be a radio frequency delay (RF) delay time or the like. Alternatively, in the case of a relay operating in a decode-and-forward (DF) method, the predetermined delay time may be demodulation and remodulation time. Accordingly, the predetermined delay time between the first section of step S310 and the second section of step S320 may be a delay time for a relaying operation as described above. That is, the predetermined delay time means a time delay necessarily required by characteristics of an RF element included in a relay device or demodulation and re-modulation processing, regardless of the AF method or the DF method, and is a value already known to the relay device Alternatively, it may be a predefined or preset value.

)에 추가적으로 의도적인(intended) 지연(

)이 존재할 수 있다. 즉, 본 발명의 일 실시예에서는 릴레이가 미리 알고 있는 시간 지연(

)과 의도적인 시간 지연(

)을 함께 이용하여 제1 구간과 제2 구간을 설정할 수 있다. Referring to FIG. 5, between the first period and the second period, a delay due to the relaying operation described above with reference to FIG. 4 (

) in addition to the intentional delay (

) may exist. That is, in one embodiment of the present invention, the time delay known by the relay in advance (

) and an intentional time delay (

) can be used together to set the first section and the second section.

이라 할 수 있다. 한편, 제2 구간은 릴레이가 신호 전송을 수행하는 구간이며, 제2 구간에서 측정되는 수신 파워 값은 수학식 1의

일 수 있다. 제1 구간과 제2 구간에서 측정되는 수신 신호 파워는 소스 노드에 적용된 송신 빔(즉, 송신 빔의 방향)과 릴레이의 수신 빔(즉, 수신 빔의 방향), 릴레이의 송신 빔(즉, 송신 빔의 방향)에 의해 달라질 수 있다. 이 경우, 수신 파워 측정을 위해서는 제1 구간과 제2 구간에 설정된 릴레이의 AGC(automatic gain control) 값이 동일해야 한다. As an example of signal measurement performed in the first interval and the second interval, an increase or decrease in received power between the first interval and the second interval may be measured. The first period is before the relay starts transmitting the signal, and the received power value measured in the first period is

can be said Meanwhile, the second period is a period in which the relay transmits a signal, and the received power value measured in the second period is

can be The received signal power measured in the first period and the second period is the transmit beam applied to the source node (ie, the direction of the transmit beam), the receive beam of the relay (ie, the direction of the receive beam), and the transmit beam of the relay (ie, transmit beam). beam direction). In this case, in order to measure the received power, the automatic gain control (AGC) values of the relays set in the first period and the second period must be the same.

Meanwhile, the signal measured in the first interval and the second interval may include a broadcast transmission signal such as a synchronization signal/physical broadcast channel (SS/PBCH) block of the 5G NR system. Alternatively, the signal measured in the first period and the second period includes a physical sidelink broadcast channel (PSBCH) transmitted before a physical sidelink control channel (PSCCH) or a physical sidelink control channel (PSSCH) in the sidelink channel of the 5G NR V2X standard. can do. Alternatively, the signal measured in the first interval and the second interval may be a preamble before a transmission payload, such as short training format (STF) or long training format (LTF) of the WiFi standard.

을 계산할 수 있다(S330). Referring back to FIG. 3 , the relay may calculate the amount of self-interference in the first beam based on the measurement result during the first interval and the measurement result during the second interval. That is, the relay compares the measurement result during the second period with the measurement result during the first period, and determines the amount of self-interference of the first beam.

can be calculated (S330).

와 계산된 자기 간섭량

을 비교하고(S340), 계산된 자기 간섭량

이 설정된 임계값

보다 작은 경우(또는, 설정된 임계값

이하인 경우), 상기 소스 노드를 위한 릴레이 동작을 수행하기로 결정할 수 있다(S351). 한편, 계산된 자기 간섭량

이 설정된 임계값

보다 큰 경우(또는, 설정된 임계값

이상인 경우), 상기 릴레이는 상기 소스 노드를 위한 릴레이 동작을 수행하지 않기로 결정할 수 있다(S352).Next, the relay sets the threshold value for self-interference management.

and the calculated magnetic interference

Compare (S340), and the calculated amount of magnetic interference

Threshold set by this

less than (or set threshold

or less), it may be determined to perform a relay operation for the source node (S351). On the other hand, the calculated amount of magnetic interference

Threshold set by this

greater than (or a set threshold

above), the relay may decide not to perform a relay operation for the source node (S352).

보다 작은(또는, 상기 설정된 임계값

이하의) 자기 간섭량을 가지는 L개의 송신 빔들이 존재할 수 있다. 이 경우, 릴레이는 이전 빔의 자기 간섭량(

)과 현재 빔의 자기 간섭량(

)을 비교하여(S360), 더 적은 자기 간섭량을 가지는 송신 빔을 선택하고 선택된 빔을 이용하여 소스 노드를 위한 릴레이 동작을 수행할 수 있다(S361). 한편, 다른 실시예로서, 릴레이는 릴레이의 처리 속도 및 메모리 등에 따라 N개의 송신 빔들 중에서 가장 작은 자기 간섭량을 가지는 송신 빔을 선택하고 선택된 빔을 이용하여 소스 노드를 릴레이 동작을 수행할 수 있다. Meanwhile, when N transmission beams exist for the relay, the set threshold value among the N transmission beams

less than (or the set threshold

There may be L transmission beams having an amount of self-interference (below). In this case, the relay determines the amount of magnetic interference of the previous beam (

) and the amount of magnetic interference of the current beam (

) is compared (S360), a transmission beam having a smaller amount of self-interference is selected, and a relay operation for the source node may be performed using the selected beam (S361). Meanwhile, as another embodiment, the relay may select a transmission beam having the smallest amount of self-interference among N transmission beams according to the processing speed and memory of the relay, and perform a relay operation on the source node using the selected beam.

6 is a conceptual diagram for explaining an operating region of each relay according to an operating method of an IFD-type relay according to an embodiment of the present invention.

에 따라서 송신 빔이 커버할 수 있는 영역이 한정된다. 예를 들어, 도 6을 참조하면 릴레이 #1은 영역1의 목적지 노드에게 신호를 전달할 수 있지만, 해당 영역에 목적지 노드가 없을 경우, 릴레이로 선택되지 않을 수 있다. 릴레이 #2와 #3는 각각 영역2와 영역3을 릴레이 가능 영역으로 설정하고, N개 송신 빔들 중 상기 영역을 커버하는 L개의 송신 빔들 중 가장 낮은 자기 간섭을 가지는 빔을 송신 빔으로 선택할 수 있다.As described above, in the IFD-type relay according to an embodiment of the present invention, the threshold value set for self-interference management

According to this, the area that can be covered by the transmission beam is limited. For example, referring to FIG. 6 , relay #1 may deliver a signal to a destination node in area 1, but may not be selected as a relay if there is no destination node in the area. Relays #2 and #3 may set regions 2 and 3 as relayable regions, respectively, and select a beam having the lowest self-interference among L transmission beams covering the region among N transmission beams as a transmission beam. .

7 is a block diagram for explaining the structure of an IFD-type relay according to an embodiment of the present invention.

Referring to FIG. 7, the IFD-type relay according to an embodiment of the present invention largely includes an antenna unit 710, analog beamformers 720 and 725, RF converters 730 and 735, and beam measurement. A unit 740 and a beam management unit 750 may be included. Here, the analog beamformers 720 and 725 and the RF converters 730 and 735 are separately shown as transmitting and receiving sides, respectively.

The antenna unit 710 is composed of a plurality of antennas and polarized antennas, and may be composed of a plurality of transmit antennas and receive antennas separated from each other or a divider (circulator, etc.) connected to each antenna.

Analog beamformers 720 and 725 for controlling self-interference generated in the IFD-type relay are connected to the transmit antenna and the receive antenna, respectively. Each beamformer may be composed of elements (eg, a phase shifter) for adjusting gain and phase.

The RF converters 730 and 735 may be largely composed of a frequency converter and a signal amplifier, and in detail, convert a baseband signal to be transmitted into an RF band signal or convert a received RF band signal into a baseband signal. A local oscillator (LO) and an up/down converter that play the role of changing, HPA (high power amplifier) and LNA (low noise amplifier) that amplify the output size of the input signal ), a variable gain amplifier (VGA), and the like. In particular, VGA may be a component for automatic gain control (AGC) 736. The AGC 736 performs a function of adjusting the magnitude (gain) of a received signal including self-interference in order to measure a signal-to-interference ratio (SIR) level of a signal received through beam control. As mentioned above, the AGC values in the first section of step S310 and the second section of step S320 should be set identically.

The beam measurer 740 may perform a function of measuring an amount of self-interference or a signal-to-interference ratio according to beam formation of a received signal and a transmitted signal. The beam measurement unit 740 may include an RF conversion unit 731 and a digital modem unit. However, the beam measurement unit 740 may be configured in the time or frequency domain of the digital modem unit according to the measurement method.

The beam management unit 750 performs a beam selection function to reduce an interference signal including self-interference received by the IFD type relay, and is included in the digital modem unit or separately depending on hardware implementation complexity, speed, selection method, etc. It may consist of a device of

In the IFD-type relay operation method according to an embodiment of the present invention described with reference to FIG. 3, the beam manager 750 includes the analog beamformers 720 and 725, the RF converters 730 and 735, and the beam This may be performed by controlling the measuring unit 740 . To this end, the beam management unit 750 may include at least one processor and a memory including at least one command executed by the at least one processor.

That is, the beam management unit 750 measures the signal received from the source node during a first interval using the beam measurement unit 740; Using the analog beam forming units 720 and 725 and the beam measurement unit 740, during a second interval after a predetermined delay time from the first interval, a signal received from the source node and a signal received from the relay measuring a signal received after being transmitted through 1 beam; The measurement result during the second period and the measurement result during the first period may be compared to calculate the amount of self-interference of the first beam.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded on a computer readable medium. Computer readable media may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on a computer readable medium may be specially designed and configured for the present invention or may be known and usable to those skilled in computer software.

Examples of computer readable media include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes generated by a compiler. The hardware device described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the claims below. You will be able to.

Claims (18)

As a method of operating a relay operating in the same band full duplex (IFD) method,
measuring a signal received from a source node during a first period;
measuring a signal received from the source node and a signal received after being transmitted through a first beam from the relay during a second interval after a predetermined delay time from the first interval;
calculating a self-interference amount of the first beam by comparing a measurement result during the second period with a measurement result during the first period; and
Determining to perform a relay operation for the source node when the amount of self-interference of the first beam is predetermined or smaller than a preset threshold;
When there are N transmission beams in the relay, the amount of self-interference of the L transmission beams among the N transmission beams is less than the predetermined or preset threshold and the amount of self-interference of the ith beam among the L transmission beams is i -If it is less than the amount of self-interference of the 1st beam, the relay uses the i-th beam to perform a relay operation for the source node, or the relay uses the transmission beam with the smallest amount of self-interference among the N transmission beams to perform a relay operation for the source node, wherein N is a natural number and L is a natural number less than or equal to N,
How the relay works. The method of claim 1,
The predetermined delay time is a delay time for a relaying operation of the relay,
How the relay works. The method of claim 1,
The predetermined delay time is a time obtained by adding a predetermined additional delay time to the delay time for a relaying operation of the relay,
How the relay works. The method of claim 1,
In the first period and the second period, the AGC (automatic gain control) value of the relay is set to be the same,
How the relay works. The method of claim 1,
The signal measured in the first period and the second period is a synchronization signal, a short training format (STF) preamble, or a long training format (LTF) preamble,
How the relay works. The method of claim 1,
The relay, the source node, and the destination node operate in a beam-sweeping manner,
How the relay works. delete delete delete As a relay operating in the same band full duplex (IFD) method,
an analog beamformer connected to at least one transmit antenna and at least one receive antenna;
an RF converter for converting a baseband signal into an RF band signal or converting an RF band signal into a baseband signal, and controlling a gain of a received signal;
a beam measuring unit measuring a signal received from a source node and a signal received after being transmitted from the relay through the first beam; and
A beam management unit controlling operations of the analog beamforming unit, the RF conversion unit, and the beam measurement unit;
The beam management unit measures a signal received from a source node during a first interval using the beam measurement unit; A signal received from the source node and a signal received from the relay are transmitted through the first beam during a second interval after a predetermined delay time after the first interval by using the analog beamforming unit and the beam measuring unit measure the signal; Comparing a measurement result during the second period with a measurement result during the first period to calculate an amount of self-interference of the first beam; When the amount of self-interference of the first beam is predetermined or smaller than a preset threshold, the beam management unit is set to determine to perform a relay operation for the source node,
When the analog beamformer forms N transmission beams, the amount of self-interference of L transmission beams among the N transmission beams is smaller than the predetermined or preset threshold and the amount of self-interference of the ith beam among the L transmission beams If the self-interference amount of the i−1 th beam is less than the self-interference amount of the i−1 th beam, the beam manager determines to perform a relay operation for the source node using the i th beam, or the beam manager determines the smallest self-interference among the N transmission beams. It is determined to perform a relay operation for the source node using a transmission beam having an interference amount, wherein N is a natural number and L is a natural number less than or equal to N,
relay. The method of claim 10,
The predetermined delay time is a delay time for a relaying operation of the relay,
relay. The method of claim 10,
The predetermined delay time is a time obtained by adding a predetermined additional delay time to a delay time for a relaying operation of the relay.
relay. The method of claim 10,
In the first period and the second period, the beam management unit sets the same automatic gain control (AGC) value of the RF conversion unit,
relay. The method of claim 10,
The signal measured in the first period and the second period is a synchronization signal, a short training format (STF) preamble, or a long training format (LTF) preamble,
relay. The method of claim 10,
The relay, the source node, and the destination node operate in a beam-sweeping manner,
relay. delete delete delete

Images