KR102449734B1 - METHOD AND APPARATUS FOR ADAPTIVE COMMUNICATION IN mobile wireless backhaul network - Google Patents

Abstract

An adaptive communication method of a base station in a mobile wireless backhaul network includes the steps of: acquiring a frame transmission/reception timing of a terminal; periodically searching for a terminal synchronization signal transmitted from the terminal; when the terminal synchronization signal is detected, the terminal synchronization signal and estimating the frame transmission/reception timing of the base station to the terminal based on the frame transmission/reception timing of the terminal, and transmitting a base station synchronization signal to the terminal based on the frame transmission/reception timing of the base station.

Description

Adaptive communication method and apparatus in a mobile wireless backhaul network {METHOD AND APPARATUS FOR ADAPTIVE COMMUNICATION IN mobile wireless backhaul network}

The embodiment relates to an adaptive communication method and apparatus in a mobile wireless backhaul network.

In a mobile wireless backhaul network for a high-speed mobile device in which a plurality of users ride, the high-speed mobile device functions as a single terminal to transmit/receive data to and from a base station. In addition, the high-speed mobile terminal provides a data service to the user terminals inside the high-speed mobile using technologies such as Wi-Fi and a femto cell. This method has the advantage of overcoming the propagation loss that occurs in the process in which radio waves received from the outside of the high-speed moving body pass through the inside of the high-speed moving body. In addition, since the high-speed mobile terminal performs group handover at the cell boundary, it is possible to reduce the burden of each handover performed by a large number of user terminals in the high-speed mobile object.

In the mobile wireless backhaul network for high-speed mobile devices, similar to the existing cellular network, the base station provides a synchronization signal and a pilot signal as a reference, and the high-speed mobile terminal receives these signals and adapts to the frame boundary of the base station. communication is made by

On the other hand, in a mobile wireless backhaul network for a high-speed mobile device, unlike a general cellular network, a high-speed mobile terminal represents a plurality of user terminals and transmits and receives data to and from the base station. In most cases, the number of terminals communicating directly is one or none. Accordingly, it may be a waste of power for all base stations to continuously transmit a synchronization signal, a pilot signal, a base station control information signal, and the like.

An object to be solved by the embodiment is to provide an adaptive communication method and apparatus for minimizing unnecessary power consumption of a base station in a mobile wireless backhaul network supporting a high-speed moving object.

An adaptive communication method of a base station in a mobile wireless backhaul network according to an embodiment for solving the above problems includes: acquiring a frame transmission/reception timing of a terminal; periodically searching for a terminal synchronization signal transmitted from the terminal; When a synchronization signal is detected, estimating the frame transmission/reception timing of the base station to the terminal based on the terminal synchronization signal and the frame transmission/reception timing of the terminal, and a base station synchronization signal to the terminal based on the frame transmission/reception timing of the base station It may include the step of transmitting.

In addition, the adaptive communication method of a terminal in a mobile wireless backhaul network according to an embodiment includes the steps of: acquiring a frame transmission/reception timing of the terminal; transmitting a terminal synchronization signal to a base station according to the frame transmission/reception timing; Searching for a base station synchronization signal transmitted from the base station in response to a signal, when the base station synchronization signal is detected, obtaining a reception timing from the base station based on the base station synchronization signal, the frame transmission/reception timing of the terminal and the Comparing reception timings to generate timing correction information for the base station, and transmitting the timing correction information to the base station.

In addition, an adaptive communication apparatus in a mobile wireless backhaul network according to an embodiment includes a transceiver for transmitting and receiving a signal with a terminal, a synchronization signal detector for detecting a terminal synchronization signal transmitted from the terminal by searching for a signal received through the transceiver; Then, the frame transmission/reception timing of the terminal is obtained from an external server, and when the terminal synchronization signal is detected by the synchronization signal detector, the frame transmission/reception of the adaptive communication device to the terminal based on the terminal synchronization signal and the frame transmission/reception timing of the terminal and a controller for estimating timing and controlling the transceiver to transmit a base station synchronization signal based on frame transmission/reception timing of the adaptive communication device.

According to the embodiment, it is possible to minimize unnecessary power consumption of the base station in a mobile wireless backhaul network supporting a high-speed moving object.

In addition, it is possible to apply the multi-cell multi-antenna technology to the mobile wireless backhaul network supporting high-speed mobiles, thereby improving the data transmission rate in the mobile wireless backhaul network.

1 illustrates an example of a mobile wireless backhaul network supporting a high-speed mobile body.
FIG. 2 shows another example of a mobile wireless backhaul network supporting a high-speed moving object.
3 schematically illustrates an adaptive communication apparatus in a mobile wireless backhaul network according to an embodiment.
4 illustrates an example of setting a synchronization signal search period in an adaptive communication apparatus according to an embodiment.
5 is a diagram illustrating an example of estimating transmission/reception timing in an adaptive communication apparatus according to an embodiment.
6 schematically illustrates a high-speed mobile terminal according to an embodiment.
7 schematically illustrates an adaptive communication method of a base station in a mobile wireless backhaul network according to an embodiment.
8 schematically illustrates an adaptive communication method of a terminal in a mobile wireless backhaul network according to an embodiment.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification and claims, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

Throughout the specification, a terminal is a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (HR-MS) , a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), user equipment (UE), etc. may refer to, and the like, MT, MS, AMS , HR-MS, SS, PSS, AT, UE, etc. may include all or some functions.

In addition, the base station (base station, BS) is an advanced base station (advanced base station, ABS), a high reliability base station (high reliability base station, HR-BS), a Node B (node B), an advanced node B (evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR)-BS, a relay serving as a base station station, RS), a relay node (RN) serving as a base station, an advanced relay station (ARS) serving as a base station, and a high reliability relay station (HR) serving as a base station -RS), small base station [femoto base station (femoto BS), home node B (home node B, HNB), home eNodeB (HeNB), pico base station (pico BS), metro base station (metro BS), micro base station (micro BS) ), etc.], a digital base station (DU), an antenna base station (Radio Unit, RU), etc., may refer to ABS, NodeB, eNodeB, AP, RAS, BTS, MMR-BS, RS, RN, ARS , HR-RS, small base station, DU, RU, etc. may include all or some functions.

1 illustrates an example of a mobile wireless backhaul network supporting a high-speed mobile body.

A high-speed moving object refers to a moving object that moves at high speed, such as a train, a subway, a high-speed train, and a bus. A large number of users can ride inside the high-speed moving body. The high-speed moving object may include a communication terminal (hereinafter, referred to as a 'high-speed mobile terminal') mounted on the high-speed moving object.

1, in the mobile wireless backhaul network 10 supporting the high-speed moving object 100a, the high-speed mobile terminal is a terminal of a plurality of users riding inside the high-speed moving object 100a (hereinafter referred to as 'user terminal'). used) to transmit and receive data to and from the base station 200a.

The high-speed mobile terminal includes at least one transmit/receive antenna installed outside the high-speed mobile unit 100a, and may transmit/receive data to/from the base station 200a through the transmit/receive antenna.

The high-speed mobile terminal connects to at least one small cell or Wi-Fi access point (AP) located inside the high-speed mobile 100a through a wired network inside the high-speed mobile device 100a. can Accordingly, the high-speed mobile terminal can transmit and receive data to and from the user terminals through a small cell or Wi-Fi AP connected through a wired network.

The base station 200a is connected to the core network through an optical fiber or the like. Each base station 200a includes at least one transmit/receive antenna, and may transmit/receive data to/from high-speed mobile terminals through the transmit/receive antenna.

FIG. 2 shows another example of a mobile wireless backhaul network supporting a high-speed moving object, and shows a mobile wireless backhaul network to which a distributed antenna technology is applied.

Referring to FIG. 2 , in the mobile wireless backhaul network 20 to which the distributed antenna technology is applied, a base station includes a digital base station (DU) 210a and an antenna base station (RU) 220a, 220b, and 220c. The digital base station 210a performs a modem function of the base station. A plurality of antenna base stations 220a, 220b, and 220c are connected to the digital base station 210a.

In the mobile wireless backhaul network 20 to which distributed antenna technology is applied, a plurality of antenna base stations 220a, 220b, and 220c connected to one digital base station 210a are distributed. The digital base station 210a may transmit/receive data to/from high-speed mobile terminals through the distributed antenna base stations 220a, 220b, and 220c.

In the mobile wireless backhaul networks 10 and 20 for high-speed mobile devices, unlike a general cellular network, a high-speed mobile terminal represents a plurality of user terminals and transmits and receives data to and from the base station 200a (or antenna base stations 220a, 220b, 220c). do. Accordingly, the number of terminals directly transmitting and receiving data with the base station 200a (or antenna base stations 220a, 220b, 220c) is very small, and direct communication with the base station 200a (or antenna base stations 220a, 220b, 220c) It often happens that the number of terminals is one or none.

Accordingly, if all the base stations (or antenna base stations) continuously transmit a synchronization signal, a pilot signal, a base station control information signal, etc., unnecessary power consumption is generated, resulting in power wastage.

In the case of high-speed rail currently being developed worldwide, it aims to operate at a speed of 400 km/h or more. Accordingly, in the mobile wireless backhaul networks 10 and 20 for high-speed mobile devices moving at high speeds, such as high-speed rail, OFDM parameters must be determined in consideration of Doppler frequency shift due to the operating speed of high-speed mobile terminals.

When the OFDM parameter is determined in consideration of the Doppler frequency shift due to the running speed of the high-speed mobile terminal, the OFDM symbol and CP (Cyclic Prefix) length are relatively reduced while the subcarrier spacing becomes very large. Therefore, if the distance between the base stations (or antenna base stations) is not close enough, the signals received by the high-speed mobile terminal from the two base stations (or antenna base stations) cannot enter within one CP period, so multi-cell MIMO is performed. There is a problem that makes it difficult to use the technology. In particular, when the millimeter wave frequency band, which is currently in the spotlight as a 5G candidate frequency, is applied to the mobile wireless backhaul networks 10 and 20, the frequency band is higher than that of the general cellular band, so the subcarrier interval becomes larger and the length of the CP is further reduced. This makes this problem even more serious.

In order to solve these problems, in the embodiment, the high-speed mobile terminal serves as a communication standard and transmits a synchronization signal to the base station, and the base station adapts to the communication and performs communication.

Hereinafter, an adaptive communication method and apparatus in a mobile wireless backhaul network according to an embodiment will be described in detail with reference to the necessary drawings.

3 schematically illustrates an adaptive communication apparatus in a mobile wireless backhaul network according to an embodiment. 4 illustrates an example of setting a synchronization signal search period in an adaptive communication apparatus according to an embodiment. 5 is a diagram illustrating an example of estimating transmission/reception timing in an adaptive communication apparatus according to an embodiment.

Referring to FIG. 3 , the adaptive communication apparatus 2000 according to an embodiment may include a transceiver 2100 , a synchronization signal detector 2200 , modems (MODEMs) 2310 and 2320 , and a controller 2400 . The adaptive communication device 2000 may be implemented in a base station of a mobile wireless backhaul network supporting a high-speed mobile device. Taking FIG. 1 as an example, the adaptive communication apparatus 2000 may be implemented in the base station 200a in the mobile wireless backhaul network 10 . In addition, taking FIG. 2 as an example, each component of the adaptive communication apparatus 2000 may be implemented in the digital base station 210a or the antenna base stations 220a, 220b, and 220c in the mobile wireless backhaul network 20 .

The transceiver 2100 operates a plurality of beams independent of each other according to the control signal of the controller 2400, and transmits and receives signals to and from the high-speed mobile terminal through this.

The synchronization signal detector 2200 detects a synchronization signal (hereinafter, referred to as a 'terminal synchronization signal') transmitted from the high-speed mobile terminal by searching for a signal received through the transceiver 2100 . In order to reduce power consumption by minimizing processing, the synchronization signal detector 2200 periodically searches for a terminal synchronization signal only for a predetermined period (hereinafter, referred to as a 'synchronization signal search period') instead of continuously searching for a terminal synchronization signal. can be performed.

The synchronization signal detector 2200 detects the terminal synchronization signal transmitted from the high-speed mobile terminal by comparing the synchronization signal received through the transceiver 2100 with a preset signal threshold during the synchronization signal search period.

The synchronization signal detector 2200 may detect a beam in which the received signal strength of the terminal synchronization signal is the greatest among a plurality of beams operated by the transceiver 2100 when the terminal synchronization signal is detected.

The modems 2310 and 2320 perform a function of modulating or demodulating a signal transmitted and received between the adaptive communication device 2000 and the high-speed mobile terminal at a baseband terminal.

Meanwhile, although FIG. 3 illustrates the case in which the adaptive communication device 2000 includes two modems 2310 and 2320 as an example, the present invention is not limited thereto. The number of modems included in the adaptive communication device 2000 may correspond to the maximum number of high-speed mobile terminals with which the adaptive communication device 2000 must communicate simultaneously. For example, in a mobile wireless backhaul network including a high-speed rail running in both directions, since the maximum number of high-speed mobile terminals with which the adaptive communication device 2000 must communicate simultaneously is 2, the adaptive communication device 2000 has two modems. may be included.

The controller 2400 controls the overall operation of the adaptive communication device 2000 .

The controller 2400 may perform an interface function with an upper layer. The controller 2400 may receive data to be transmitted to each high-speed mobile terminal from an upper layer through an interface with an upper layer, or transmit data received from each high-speed mobile terminal to an upper layer.

The controller 2400 may set a synchronization signal search period of the synchronization signal detector 2200 .

In the mobile wireless backhaul networks 10 and 20 supporting high-speed mobile devices, high-speed mobile terminals are transmitted/received timings, that is, transmitted/received frame boundaries, by a synchronization server (not shown) such as a global positioning system (GPS). can be synchronized. A frame boundary corresponds to a start position (or a start time) and an end position (or an end point) of a frame in the time domain.

When the transmission/reception frame boundary of the high-speed mobile terminals is synchronized by the synchronization server, the controller 2400 receives the transmission/reception timing information of the high-speed mobile terminals from the synchronization server, and sets the transmission/reception frame boundary of the high-speed mobile terminals and the synchronization signal transmission timing therefrom. can be obtained In addition, the synchronization signal search period may be set based on the synchronization signal transmission timing of the high-speed mobile terminals.

4, due to the propagation delay according to the distance between the base station and the high-speed mobile terminal, a delay of a predetermined time (T1) occurs until a frame transmitted by the high-speed mobile terminal is actually received by the base station. Accordingly, the controller 2400 considers the maximum radius of a cell supported by the base station (or antenna base station) of the adaptive communication device 2000 based on the synchronization signal transmission time Ts of the high-speed mobile terminal obtained from the synchronization server. A synchronization signal search section can be set.

In general, as the distance between the high-speed mobile terminal and the base station increases, the time at which the terminal synchronization signal transmitted by the high-speed mobile terminal is received by the base station is delayed. Accordingly, the controller 2400 may estimate the maximum delay time until the terminal synchronization signal transmitted by the high-speed mobile terminal is received by the base station based on the maximum radius of the cell supported by the corresponding base station (or antenna base station). When the maximum delay time is predicted, the controller 2400 may set the synchronization signal search period by including a period equal to the maximum delay time from the time when the high-speed mobile terminal transmits the terminal synchronization signal.

Meanwhile, in the embodiment, the controller 2400 sets the synchronization signal search section of the synchronization signal detector 2200 as an example, but the embodiment is not limited thereto. The interval may be set by the synchronization signal detector 2200 . In this case, the controller 2400 may transfer the transmission/reception timing information of the high-speed mobile terminals obtained from the synchronization server to the synchronization signal detector 2200 so that the synchronization signal detector 2200 can set the synchronization signal search section.

The controller 2400 may control whether the adaptive communication device 2000 is activated.

When there is no high-speed mobile terminal communicating with the adaptive communication device 2000, the controller 2400 controls the adaptive communication device 2000 to be in an inactive state. That is, the transceiver 2100 stops transmitting the synchronization signal, the pilot signal, the control information signal, and the like.

When a terminal synchronization signal is detected from the synchronization signal detector 2200 in a state in which the adaptive communication apparatus 2000 is deactivated, the controller 2400 controls the adaptive communication apparatus 2000 to an activated state.

Meanwhile, even if the controller 2400 switches the adaptive communication device 2000 to the inactive state, the synchronization signal detector 2200 is periodically switched to the active state to detect the terminal synchronization signal during a preset synchronization signal search period. can do.

When a terminal synchronization signal is detected through the synchronization signal detector 2200 , the controller 2400 may estimate the transmission/reception timing of the adaptive communication device 2000 based on the detection.

When the terminal synchronization signal is detected through the synchronization signal detector 2200, the controller 2400 acquires the frame boundary of the frame received by the adaptive communication device 2000 from the high-speed mobile terminal based on this. Then, by comparing the frame boundary of the frame actually received by the adaptive communication device 2000 and the frame boundary of the transmission frame of the high-speed mobile terminal, the propagation delay time between the high-speed mobile terminal and the adaptive communication apparatus 2000, that is, the high-speed mobile terminal is determined. The propagation delay time until the transmitted frame is received by the adaptive communication device 2000 is calculated. The frame boundary of the transmission frame of the high-speed mobile terminal can be predicted from the transmission/reception timing of the high-speed mobile terminal received from the synchronization server.

When the propagation delay time between the high-speed mobile terminal and the adaptive communication device 2000 is calculated, the controller 2400 estimates transmission/reception timing of the adaptive communication device 2000 based on the calculated propagation delay time.

5, when the propagation delay time estimated from the terminal synchronization signal is T1, the controller 2400 determines that the reception timing (or reception frame boundary) of the adaptive communication device 2000 is the transmission timing (or transmission frame) of the high-speed mobile terminal. boundary) by T1. In addition, the controller 2400 sets the transmission timing (or transmission frame boundary) of the adaptive communication device 2000 to be ahead of the reception timing (or reception frame boundary) of the high-speed mobile terminal by T1 by T1, It is set to advance by twice T1 than the reception timing (or reception frame boundary) of .

When the transmission/reception timing with the high-speed mobile terminal is estimated, the controller 2400 transmits a synchronization signal (hereinafter, referred to as a 'base station synchronization signal') to the high-speed mobile terminal in response to the estimated transmission timing. can control

Upon receiving this, the high-speed mobile terminal acquires the frame boundary of the frame received from the base station from the base station synchronization signal. In addition, timing correction information is calculated by comparing the received frame boundary obtained based on the base station synchronization signal with a preset received frame boundary. Then, the calculated timing correction information is fed back to the adaptive communication device 2000 .

When the timing correction information is received from the high-speed mobile terminal, the controller 2400 corrects an error in transmission/reception timing with the high-speed mobile terminal based on the received timing correction information, and performs communication with the high-speed mobile terminal based on the error-corrected transmission/reception timing.

Meanwhile, in the mobile wireless backhaul networks 10 and 20 supporting high-speed mobile devices, a situation in which one base station (or antenna base station) must communicate with two or more high-speed mobile terminals may occur. Referring to FIG. 2 as an example, one antenna base station 220b communicates with the two high-speed mobile terminals of the two high-speed mobile devices 100b and 100c.

As described above, in a situation where communication with two or more high-speed mobile terminals is required at the same time, when the high-speed mobile terminals to communicate are located in different places, the distance between the adaptive communication apparatus 2000 and each high-speed mobile terminal may be different from each other. Accordingly, even if the transmission/reception timings of the high-speed mobile terminals are synchronized by the synchronization server, the timing at which the adaptive communication apparatus 2000 receives the terminal synchronization signal from each high-speed mobile terminal may be different from each other. From the standpoint of the adaptive communication apparatus 2000, when the timing of receiving the synchronization signal from each high-speed mobile terminal is different, the transmission/reception timing with each high-speed mobile terminal estimated based on the terminal synchronization signal is also different.

The adaptive communication apparatus 2000 operates a plurality of beams independent of each other in order to simultaneously communicate with a plurality of high-speed mobile terminals having different corresponding transmission/reception timings. That is, the adaptive communication device 2000 is connected to different modems 2310 and 2320 and independently operates a plurality of beams capable of setting different transmission/reception timings. It is possible to support a plurality of different high-speed mobile terminals. The adaptive communication apparatus 2000 selects a beam most suitable for each high-speed mobile terminal from among a plurality of beams in operation and performs communication with each high-speed mobile terminal.

The controller 2400 may allocate one of a plurality of beams to each high-speed mobile terminal based on a terminal synchronization signal received from each high-speed mobile terminal.

In the process of detecting the terminal synchronization signal transmitted from the high-speed mobile terminal through the synchronization signal detector 2200 , the controller 2400 detects the highest received signal strength of the terminal synchronization signal among the plurality of beams operated by the transceiver 2100 . Acquire the information of the beam. And, among the plurality of beams, a beam having the largest received signal strength of the terminal synchronization signal is allocated to the corresponding high-speed mobile terminal.

When one of a plurality of beams is allocated to the high-speed mobile terminal, the controller 2400 controls the transceiver 2100 to communicate with the high-speed mobile terminal through the corresponding beam. Accordingly, the transceiver 2100 transmits a base station synchronization signal, a pilot signal, a base station control information signal, and the like, to each high-speed mobile terminal by using the beam allocated to each high-speed mobile terminal.

In the adaptive communication device 2000 having the above structure, the functions of the transceiver 2100, the synchronization signal detector 2200, the modem 2300, and the controller 2400 are performed by one or more central processing units (CPUs) or other functions. It may be performed by a processor implemented by a chipset, a microprocessor, or the like.

6 schematically illustrates a high-speed mobile terminal according to an embodiment.

Referring to FIG. 6 , the high-speed mobile terminal 1000 according to the embodiment may include a transceiver 1100 , a modem 1200 , and a terminal controller 1300 .

The transceiver 1100 transmits and receives signals to and from the base station according to the control signal of the terminal controller 1300 .

The modem 1200 modulates or demodulates a signal transmitted/received between the high-speed mobile terminal 1000 and the base station at the baseband terminal. For example, when a signal is received from the base station through the transceiver 1100, the modem 1200 demodulates and decodes it, and transmits the demodulated and decoded data to the small cell or Wi-Fi AP through a wired network.

The terminal controller 1300 controls the overall operation of the high-speed mobile terminal 1000 .

When power is supplied to the high-speed mobile terminal 1000 , the terminal controller 1300 receives transmission/reception timing information from a synchronization server (not shown). In addition, the transceiver 1100 may be controlled to communicate with the base station based on the received transmission/reception timing information. For example, the terminal controller 1300 controls the transceiver 1100 to periodically transmit a terminal synchronization signal to the base station based on the transmission timing information.

When the base station synchronization signal is received from the base station in response to the terminal synchronization signal, the terminal controller 1300 acquires a frame boundary of a frame actually received from the base station based on this. In addition, timing correction information may be calculated by comparing the frame boundary of the received frame received from the base station with the predetermined reception frame boundary of the high-speed mobile terminal 1000 . The reception frame boundary of the high-speed mobile terminal 1000 may be obtained from transmission/reception timing information received from the synchronization server.

When the timing correction information is calculated, the terminal controller 1300 controls the transceiver 1100 and the modem 1200 to feed it back to the base station.

On the other hand, when the high-speed mobile terminal 1000 transmits a terminal synchronization signal to the base station to request communication, the received signal strength of the terminal synchronization signal received from the base station due to the distance from the base station, the environment of attention, etc. exceeds the threshold value set by the base station. There may be situations where it cannot be exceeded.

When transmitting the terminal synchronization signal, the terminal controller 1300 may control the transceiver 1100 or the modem 1200 to amplify and transmit the transmission signal strength of the terminal synchronization signal in stages until the base station synchronization signal is received from the base station. . At this time, the amplification gain, amplification step, and amplification method of the terminal synchronization signal may be designed based on the frequency band characteristics and cell coverage of the mobile wireless backhaul networks 10 and 20 including the high-speed mobile terminal 1000 .

7 schematically illustrates an adaptive communication method of a base station in a mobile wireless backhaul network according to an embodiment. In FIG. 7 , the adaptive communication method in the base station may be performed by the adaptive communication apparatus 2000 described with reference to FIG. 3 .

Referring to FIG. 7 , the adaptive communication apparatus 2000 according to an embodiment receives transmission/reception timing information of high-speed mobile terminals from a synchronization server (S100).

When the transmission/reception timing information of the high-speed mobile terminals is received from the synchronization server, the adaptive communication apparatus 2000 sets a synchronization signal search period based on the received information (S110).

The synchronization signal search period is a period for the adaptive communication apparatus 2000 to search for terminal synchronization signals transmitted from high-speed mobile terminals. In order to minimize power consumption due to processing in the synchronization signal search process, the adaptive communication apparatus 2000 periodically searches for a terminal synchronization signal during a synchronization signal search period instead of continuously searching for a terminal synchronization signal.

In step S110, the adaptive communication apparatus 2000 may obtain the terminal synchronization signal transmission timing of the high-speed mobile terminals from the transmission/reception timing information of the high-speed mobile terminals received from the synchronization server, and may set a synchronization signal search period based on this. That is, the adaptive communication apparatus 2000 considers the maximum radius of a cell supported by the base station (or antenna base station) corresponding to the adaptive communication apparatus 2000 based on the synchronization signal transmission time of the high-speed mobile terminal in consideration of the synchronization signal search period. can be set.

The adaptive communication apparatus 2000 periodically searches for a terminal synchronization signal received from the high-speed mobile terminal based on the synchronization signal search period set in step S110 (S120). In step S120, the adaptive communication apparatus 2000 periodically searches for terminal synchronization signals of high-speed mobile terminals in association with a period in which high-speed mobile terminals transmit synchronization signals.

The adaptive communication apparatus 2000 compares the signals received through the transceiver 2100 with a preset threshold during the synchronization signal search period to determine whether a terminal synchronization signal transmitted from the high-speed mobile terminal is detected (S130).

If the terminal synchronization signal is not detected within the synchronization signal search period, the adaptive communication apparatus 2000 stops transmitting signals such as a base station synchronization signal, a pilot signal, and a base station control information signal and enters an inactive state or maintains an inactive state ( S140).

On the other hand, when the terminal synchronization signal transmitted from the high-speed mobile terminal is detected within the synchronization signal search period, the adaptive communication apparatus 2000 switches to an active state. Also, a transmission timing (or a transmission frame boundary) of the adaptive communication apparatus 2000 is estimated based on the detected terminal synchronization signal ( S150 ).

In step S150, when the terminal synchronization signal is detected, the adaptive communication apparatus 2000 acquires a frame boundary of a frame received by the adaptive communication apparatus 2000 from the high-speed mobile terminal based on this. When the frame boundary of the received frame received from the high-speed mobile terminal is obtained, the adaptive communication apparatus 2000 compares it with the frame boundary of the transmission frame of the high-speed mobile terminal to determine the propagation delay time between the adaptive communication apparatus 2000 and the high-speed terminal calculated, and based on this, the transmission timing of the transmission frame of the adaptive communication apparatus 2000, that is, the frame boundary of the transmission frame is estimated. The frame boundary of the transmission frame of the high-speed mobile terminal may be obtained from the transmission/reception timing of the high-speed mobile terminals received from the synchronization server through the step S100.

When the transmission timing is estimated through the step S150, the adaptive communication apparatus 2000 transmits a base station synchronization signal to the high-speed mobile terminal based on the estimation (S160). Then, timing correction information is received from the high-speed mobile terminal that has received the base station synchronization signal (S170).

Upon receiving the base station synchronization signal from the adaptive communication apparatus 2000, the high-speed mobile terminal acquires a frame boundary of a frame received from the base station based on the received base station synchronization signal. Then, the timing correction information is calculated by comparing the frame boundary of the frame received from the base station with the preset own reception frame boundary.

The adaptive communication device 2000 that has received the timing correction information fed back from the high-speed mobile terminal corrects its transmission/reception timing (or frame boundary of the transmission/reception frame) based on the feedback (S180). Then, communication with the high-speed mobile terminal is started based on the corrected transmission/reception timing (S190).

In step S190, when the timing correction is completed, the adaptive communication device 2000 notifies the high-speed mobile terminal that communication is possible, and transmits base station system information (or control information) to the high-speed mobile terminal to communicate with the high-speed mobile terminal. can start

8 schematically illustrates an adaptive communication method of a terminal in a mobile wireless backhaul network according to an embodiment. The adaptive communication method in FIG. 8 may be performed by the high-speed mobile terminal 1000 described with reference to FIG. 6 .

Referring to FIG. 8 , as power is supplied to the high-speed mobile terminal 1000 according to the embodiment (S200), it acquires its own transmission/reception timing information from the synchronization server (S210).

The high-speed mobile terminal 1000 transmits a terminal synchronization signal based on transmission/reception timing information from the synchronization server to request communication with the base station (S220).

The high-speed mobile terminal 1000 waits for reception of a base station synchronization signal responding to the terminal synchronization signal for a predetermined time after transmitting the terminal synchronization signal (S230).

If the high-speed mobile terminal 1000 does not receive the base station synchronization signal from the base station for a predetermined time (eg, during the time until the transmission time of the next terminal synchronization signal), it is determined that the synchronization signal transmission has failed. Accordingly, the high-speed mobile terminal 1000 amplifies the transmission signal strength of the terminal synchronization signal (S240) and retransmits it.

When the high-speed mobile terminal 1000 transmits a terminal synchronization signal to the base station to request communication, the signal strength of the terminal synchronization signal received from the base station does not exceed the threshold set by the base station due to the distance from the base station, the environment, etc. situations can arise.

Accordingly, the high-speed mobile terminal 1000 amplifies the signal strength of the terminal synchronization signal in stages and repeats transmission until the base station synchronization signal is received from the base station. In this case, the amplification gain, amplification step, and amplification method of the terminal synchronization signal may be designed based on the frequency band characteristics and cell coverage of the mobile wireless backhaul networks 10 and 20 including the high-speed mobile terminal 1000.

When the base station synchronization signal is received from the base station, the high-speed mobile terminal 1000 calculates a transmission/reception timing error of the base station based on this and generates timing correction information for correcting the timing error (S250). Then, the generated timing correction information is transmitted to the base station (S260).

In step S250, the high-speed mobile terminal 1000 acquires the frame boundary of the frame actually received from the base station based on the base station synchronization signal received from the base station. In addition, a timing error may be calculated by comparing a frame boundary of a received frame received from the base station with a predetermined reception frame boundary of the high-speed mobile terminal 1000, and timing correction information may be generated to correct it.

Thereafter, when the transmission/reception timing of the base station is corrected based on the fed back timing correction information, the high-speed mobile terminal 1000 starts communication with the base station (S270).

In step S270, when the timing correction in the base station is completed, the high-speed mobile terminal 1000 may receive system information (or control information) of the base station from the base station, and communicate with the base station based on the received system information (or control information).

According to the above-described embodiment, when a high-speed mobile terminal becomes a communication standard and transmits a synchronization signal to a base station in a mobile wireless backhaul network supporting a high-speed mobile object, the base station adapts to the communication and performs communication. Accordingly, the base station transmits a synchronization signal and base station control information only when there is a high-speed mobile terminal within its coverage, and can maintain an inactive state when there is no high-speed mobile terminal within its coverage. Power consumption due to periodic transmission of information and the like can be greatly reduced.

In addition, since the base station adapts its transmission/reception timing according to the transmission/reception timing of each high-speed mobile terminal, cooperative communication between multiple base stations is easy. Accordingly, when the millimeter wave band is applied to the mobile wireless backhaul network, it is possible to overcome the disadvantage that it is difficult to implement a multi-cell multi-antenna through cooperative communication. The data transfer rate can be greatly improved.

The embodiment of the present invention is not implemented only through the apparatus and/or method described above, and a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium in which the program is recorded may be implemented, Such an implementation can be easily implemented by an expert in the technical field to which the present invention pertains from the description of the above-described embodiments.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improved forms of the present invention are also provided by those skilled in the art using the basic concept of the present invention as defined in the following claims. It is within the scope of the right.

Claims (20)

In the adaptive communication method of a base station in a mobile wireless backhaul network,
obtaining a frame transmission/reception timing of the terminal;
setting a synchronization signal search period for searching for a terminal synchronization signal based on the frame transmission/reception timing of the terminal;
periodically searching for a terminal synchronization signal transmitted from the terminal during the synchronization signal search period;
estimating the frame transmission/reception timing of the base station with respect to the terminal based on the terminal synchronization signal and the frame transmission/reception timing of the terminal when the terminal synchronization signal is detected, and
Transmitting a base station synchronization signal to the terminal based on the frame transmission/reception timing of the base station,
The step of setting the synchronization signal search section comprises:
obtaining a synchronization signal transmission timing of the terminal from the frame transmission/reception timing of the terminal; and
and setting the synchronization signal search period in consideration of a maximum radius of a cell supported by the base station based on the synchronization signal transmission timing. According to claim 1,
Receiving timing correction information from the terminal receiving the base station synchronization signal, and
and correcting transmission/reception timing of the base station based on the timing correction information. delete delete According to claim 1,
If there is no terminal communicating with the base station, the adaptive communication method further comprising the step of entering an inactive state for stopping the transmission of the base station synchronization signal. 6. The method of claim 5,
When the terminal synchronization signal is detected, the adaptive communication method further comprising the step of switching to an active state. According to claim 1,
The step of obtaining the frame transmission/reception timing of the terminal comprises:
The adaptive communication method further comprising the step of receiving the frame transmission/reception timing of the terminal from an external synchronization server. According to claim 1,
The step of estimating the frame transmission/reception timing of the base station,
estimating the frame reception timing of the base station based on the terminal synchronization signal;
Comparing the frame transmission/reception timing of the terminal and the frame reception timing of the base station, calculating a propagation delay time between the terminal and the base station, and
and estimating frame transmission timing of the base station based on the propagation delay time. According to claim 1,
Further comprising the step of allocating one of a plurality of beams operated independently of each other to the terminal,
The transmitting of the base station synchronization signal to the terminal includes transmitting the base station synchronization signal to the terminal using a beam allocated to the terminal. 10. The method of claim 9,
The allocating one of the plurality of beams to the terminal includes allocating a beam having the largest received signal strength of the terminal synchronization signal among the plurality of beams to the terminal. delete delete delete An adaptive communication device in a mobile wireless backhaul network, comprising:
A transceiver for transmitting and receiving signals to and from the terminal;
A synchronization signal detector for detecting a terminal synchronization signal transmitted from the terminal by searching for a signal received through the transceiver, and
The frame transmission/reception timing of the terminal is obtained from an external server, and when the terminal synchronization signal is detected by the synchronization signal detector, the frame transmission/reception timing of the adaptive communication device to the terminal based on the terminal synchronization signal and the frame transmission/reception timing of the terminal and a controller controlling the transceiver to transmit a base station synchronization signal based on the frame transmission/reception timing of the adaptive communication device,
The synchronization signal detector periodically searches for the terminal synchronization signal during a preset search period,
The search period is set based on frame transmission/reception timing of the terminal and a maximum radius of a cell supported by a base station corresponding to the adaptive communication apparatus. 15. The method of claim 14,
The controller is
When timing correction information is received from the terminal receiving the base station synchronization signal, the adaptive communication apparatus corrects frame transmission/reception timing of the adaptive communication apparatus based on the timing correction information. delete 15. The method of claim 14,
The controller stops the signal transmission of the transceiver when there is no terminal communicating with the adaptive communication device. 15. The method of claim 14,
The transceiver operates a plurality of beams independent of each other,
The controller is configured to control the transceiver to transmit the base station synchronization signal using one of the plurality of beams. 19. The method of claim 18,
The synchronization signal detector detects a beam having the largest received signal strength of the terminal synchronization signal among the plurality of beams,
The controller is configured to control the transceiver to transmit the base station synchronization signal using a beam having the largest received signal strength of the terminal synchronization signal. 15. The method of claim 14,
The controller estimates the frame reception timing of the base station based on the terminal synchronization signal, and calculates a propagation delay time between the terminal and the base station by comparing the frame transmission/reception timing of the terminal and the frame reception timing of the base station, An adaptive communication apparatus for estimating frame transmission timing of the base station based on the propagation delay time.

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