KR101197868B1 - Wireless relay device and wireless relay method - Google Patents

Abstract

The wireless relay device 100 is applied to a wireless communication system in which a period during which downlink data is transmitted and a time during which uplink data is transmitted are provided in time division in a communication time frame divided on a time axis. The wireless relay device 100 performs a donor transceiver 120D for exchanging data with a wireless base station, a remote transceiver 120R for exchanging data with a wireless terminal, and a donor transceiver 120D in at least one communication time frame. The controllers 130D and 130R which alternately perform control to operate and stop the remote transceiver 120R and to stop the donor transceiver 120D and operate the remote transceiver 120R in at least one communication time frame. It is provided.

Description

Wireless relay device and wireless relay method {WIRELESS RELAY DEVICE AND WIRELESS RELAY METHOD}

The present invention relates to a radio relay apparatus and a radio relay method for relaying data transmitted and received by a first radio communication apparatus and a second radio communication apparatus in a radio communication system employing time division multiplexing.

Background Art Conventionally, wireless relay devices for relaying data transmitted and received by a first wireless communication device such as a wireless base station and a second wireless communication device such as a wireless terminal are widely used (see Patent Document 1, for example). The radio relay apparatus includes a first transceiver for performing first transmission and reception for transmitting and receiving data with a first radio communication device, and a second transceiver for performing second transmission and reception for transmitting and receiving data with a second radio communication device.

In addition, a time division duplex (TDD) method is known as a method of realizing bidirectional communication in a wireless communication system. In the TDD scheme, a first period (for example, a downstream frame) in which data is transmitted from a first radio communication device to a second radio communication device, and data is transmitted from the second radio communication device to the first radio communication device. A second period (e.g., uplink frame) to be transmitted is time-divided so that respective communication time frames (communication frames) separated on the time axis are provided.

In a wireless communication system employing a TDD scheme, when a wireless relay device is used, the first transceiver receives data from the first radio communication device in a first period, and the second transceiver transmits data to the second radio communication device. . Similarly, in addition to the second transceiver receiving data from the second radio communication device in the second period, the first transceiver transmits the data to the first radio communication device.

Therefore, the radio waves radiated from the antenna of the second transceiver in the first period proceed to the antenna of the first transceiver and the radio waves radiated from the antenna of the first transceiver in the second period proceed to the antenna of the second transceiver. This progress is a problem that the first transceiver and the second transceiver are affected by each other by mutual interference.

[Previous Technical Documents]

Patent Document 1: Japanese Patent Application Laid-Open No. 2008-67386 ([Summary], etc.)

In order to avoid the influence of the above interference, any of the following methods (a) to (c) can be considered. (a) Increase the arrangement interval of each antenna of the first transceiver and the second transceiver, or arrange a radio wave shielding plate between the antennas. (b) Adopt advanced signal processing techniques to eliminate the effects of interference. (c) Communication frequencies are used at large intervals for the first transceiver and the second transceiver.

However, in the above methods (a) and (b), there is a problem that the size and cost of the radio relay apparatus increase. In the method (c), the communication frequency that the radio relay apparatus can use is determined in advance, and there is a problem that it is difficult to change the communication frequency.

Thus, the present invention provides a wireless relay apparatus and a wireless relay method which can continue data relaying while avoiding the influence of interference in the wireless relay apparatus without changing the communication frequency, and suppress the increase in size and cost. For the purpose of

MEANS TO SOLVE THE PROBLEM In order to solve the above-mentioned subject, this invention has the following characteristics. First, according to the first aspect of the present invention, a first transmission of data from a first wireless communication device (for example, wireless base station 200) to a second wireless communication device (for example, wireless terminal 300). Period (e.g., downlink subframe period t1) and a second period (e.g., uplink subframe period t2) in which data is transmitted from the second radio communication device to the first radio communication device. In the wireless communication system (wireless communication system 1) provided in time division for each communication time frame (communication frame period Tn) divided on the time axis, the first wireless communication device and the second wireless communication device are provided. A wireless relay device (wireless relay device 100) for relaying data to be transmitted and received is provided, and the wireless relay device receives data from the first radio communication device in the first period, and the second period in the second period. 1 Send data to the wireless communication device. A first transmission / reception unit (donor transceiver 120D) that performs a first transmission / reception to be transmitted, and transmits data to the second wireless communication device in the first period, and the second wireless communication device in the second period. A second transmission / reception unit (remote transmission / reception unit 120R) that performs second transmission / reception to receive data from the controller, and a control unit (control unit 130D, 130R) that controls the first transmission / reception and the second transmission / reception. The control unit includes: a first control for performing the first transmission / reception and stopping the second transmission / reception for at least one communication time frame, and stopping the first transmission / reception in the at least one communication time frame and the second transmission / reception. Executes a second control for executing.

According to such a wireless relay device, the control unit performs first control to execute the first transmission / reception and stop the second transmission / reception for at least one communication time frame, whereby the radio waves radiated from the first transmission / reception unit are transmitted to the second transmission / reception unit. Interference can be prevented. Further, the controller prevents the radio waves radiated from the second transceiver from interfering with the first transceiver by performing a second control for stopping the first transmission / reception and executing the second transmission / reception for at least one communication time frame. can do. In the first control, the first transmission / reception can be performed, and in the second control, the second transmission / reception can be performed, so that data can be relayed continuously. In addition, since only the control of the control unit executes or stops each of the first transmission / reception and the second transmission / reception on a communication time frame basis is required, it is not necessary to change the communication frequency, and the above (a) or (b In comparison with the above method, an increase in the size and cost of the radio relay apparatus can be suppressed.

According to a first aspect of the present invention, the second aspect of the present invention is that the control unit alternately executes the first control and the second control.

According to a first or second aspect of the present invention, the third aspect of the present invention is the second transmission / reception unit, wherein the synchronization information (used for setting and maintaining the synchronization between the wireless relay device and the second wireless communication device) For example, a preamble) is transmitted to the second wireless communication device, and the control unit transmits a timing at which the second transceiver transmits the synchronization information to the second wireless communication device on a time axis, starting timing of the communication time frame. The shift is made before (start timing tO).

According to a first aspect of the present invention, in a fourth aspect of the present invention, in the wireless communication system, wireless communication in accordance with orthogonal frequency division multiplexing is executed.

A fifth aspect of the present invention is the first aspect of the present invention, wherein the first radio communication device is a radio base station (wireless base station 200), and the second radio communication device is a radio terminal (wireless terminal 300). Let's make a point.

A sixth aspect of the present invention is a first period for transmitting data from a first radio communication device to a second radio communication device, and a second period for transmitting data from the second radio communication device to the first radio communication device. In the wireless communication system provided in time division for each communication time frame divided on a time axis, the wireless relay device is used for a wireless relay device for relaying data transmitted and received by the first wireless communication device and the second wireless communication device. A wireless relay method is provided, the wireless relay method comprising: a first transmission and reception for receiving data from the first wireless communication device in the first period and transmitting data to the first wireless communication device in the second period; A second transmission / reception for transmitting data to the second wireless communication device in a first period and receiving data from the second wireless communication device in the second period. And in the controlling step, a first control is executed to execute the first transmission / reception and stop the second transmission / reception for at least one communication time frame, and to control the first during at least one communication time frame. The second aspect is to perform a second control for stopping transmission and reception and executing the second transmission and reception.

According to the present invention, a data relay can be continued while avoiding the influence of interference in the wireless relay device without changing the communication frequency, and a wireless relay device and a wireless relay method which can suppress an increase in size and cost can be provided. have.

1 is a schematic structural diagram of a wireless communication system according to an embodiment of the present invention.
2 (a) is a view showing an example of the configuration of a communication frame used in a wireless communication system according to an embodiment of the present invention, Figure 2 (b) is a frequency used in a wireless communication system according to an embodiment of the present invention It is a figure which shows an example of a band.
3 is a block diagram showing a functional block configuration of a wireless relay apparatus according to an embodiment of the present invention.
4 is a time chart for explaining the schematic operation of the radio relay apparatus according to the embodiment of the present invention.
5 is a time chart for explaining the operation of the wireless communication system according to an embodiment of the present invention.
6 is a view for explaining scanning used in the wireless relay apparatus according to the embodiment of the present invention.

Next, a wireless communication system according to an embodiment of the present invention will be described with reference to the drawings. Specifically, (1) schematic configuration of the wireless communication system, (2) configuration of the wireless relay device, (3) schematic operation of the wireless relay device, (4) operation of the wireless communication system, (5) operation and effect, ( 6) Other embodiments will be described. In the description of the drawings in the following embodiments, the same or similar parts have the same or similar reference numerals.

(1) Schematic Configuration of Wireless Communication System

1 is a schematic configuration diagram of a wireless communication system 1 according to the present embodiment.

As shown in FIG. 1, the radio communication system 1 includes a radio relay apparatus 100, a radio base station 200, a radio terminal 300, and a radio terminal 400. The radio communication system 1 is configured in accordance with WiMAX (IEEE802.16). That is, the orthogonal frequency division multiplexing (OFDM) / orthogonal frequency division multiple access (OFDMA) system and the time division multiplexing (TDD) system are adopted for the radio communication system 1.

The OFDM / OFDMA system uses multiple subcarriers orthogonal to each other to realize multiple access. The TDD system realizes bidirectional communication by time-dividing uplink communication and downlink communication in one communication frame (communication time frame). On the other hand, "uplink" is a direction from the wireless terminal 300 to the wireless base station 200, and "downlink" is a direction from the wireless base station 200 to the wireless terminal 300.

The radio relay apparatus 100 relays data transmitted and received by the radio base station 200 and the radio terminal 300. By this structure, even if the wireless terminal 300 is located outside the range of the cell (communication area) of the wireless base station 200 or in the periphery (cell fringe) of the cell, the wireless relay device 100 Through this, data can be exchanged with the wireless base station 200 more reliably. In the example of FIG. 1, the wireless relay device 100 is installed in the home H to perform wireless communication with the wireless terminal 300 located in the home H. The wireless relay device 100 is required to be small and inexpensive. On the other hand, the wireless terminal 400 exchanges data directly with the wireless base station 200 without relaying data to the wireless relay device 100.

FIG. 2A is a diagram illustrating an example of a configuration of a communication frame FR used in the wireless communication system 1. In WiMAX, downlink directional communication is executed first in a communication frame period T of about 5 ms, and then uplink communication is performed. Specifically, as shown in Fig. 2A, the communication frame FR includes a downlink subframe SFR1 and an uplink subframe SFR2 disposed after the downlink subframe SFR1. .

Hereinafter, the period during which downlink communication is performed in the communication frame period T is called a downlink subframe period t1 (first period), and the period during which uplink communication is executed within the communication frame period T. Is called an uplink subframe period t2 (second period). In general, since the downlink communication requires a larger communication capacity than the uplink communication, the time length of the downlink subframe period t1 is longer than the time length of the uplink subframe period t2.

The head part of the downlink subframe SFR1 is an area in which various control data is arranged, and thereafter, a burst area in which data bursts are arranged. The control data includes a preamble which is a known symbol used for setting and maintaining synchronization, a MAP indicating the arrangement status of data bursts, and the like. The deployment situation here represents the time and frequency used to transmit the data burst. The MAP is composed of a DL-MAP indicating an arrangement status of the downlink data burst and a UL-MAP indicating an arrangement status of the uplink data burst.

A guard time (TTG: Transmit Transition Gap) is provided between the downlink subframe SFR1 and the uplink subframe SFR2. Similarly, a guard time (RTG: Receive Transition Gap) is provided between the uplink subframe (SFR2) and the next communication frame. For example, in the wireless base station 200, TTG is the guard time when switching from transmission to reception, and RTG is the guard time when switching from reception to transmission.

2B is a diagram showing an example of a frequency band used in the wireless communication system 1. As shown in Fig. 2 (b), the frequency band available for the wireless relay device 100 in the wireless communication system 1 is predetermined. In the example of Fig. 2 (b), a frequency band of 30 MHz is available, and the frequency band is divided into three communication frequencies each having 10 MHz. Two communication frequencies on the high-frequency side are used for wireless communication of the wireless base station 200 and the wireless relay device 100, and one communication frequency on the low-frequency side is the wireless terminal 300 and the wireless relay device 100. Used for wireless communication. Thus, a communication frequency close to the radio communication between the radio base station 200 and the radio relay apparatus 100 and the radio communication between the radio terminal 300 and the radio relay apparatus 100 is used.

(2) Configuration of wireless relay device

Next, the configuration of the wireless relay device 100 will be described. 3 is a block diagram showing a functional block configuration of the radio relay apparatus 100.

As shown in FIG. 3, the wireless relay device 100 includes a donor communication unit 110D used for wireless communication with the wireless base station 200, and a remote communication unit 110R used for wireless communication with the wireless terminal 300. Own) The donor communication unit 110D has a communication function equivalent to that of the radio terminal, and the remote communication unit 110R has a communication function equivalent to the radio base station. The donor communication unit 110D and the remote communication unit 110R are connected by wire using Ethernet (registered trademark) or the like.

The donor communication unit 110D includes a donor transceiver 120D (first transceiver), a controller 130D, a storage unit 172, an interface (I / F) unit 173, and an indicator 174. . The donor transmission / reception unit 120D performs donor transmission / reception (first transmission / reception) for transmitting / receiving data with the wireless base station 200 in accordance with OFDM / OFDMA and TDD schemes. Specifically, donor transceiver 120D includes donor antenna 161, transmit / receive switch 162, power amplifier (PA) 163, low noise amplifier (LNA) 164, and radio frequency / baseband ( RF / BB) section 165 is provided.

The control unit 130D is configured by, for example, a CPU, and controls various functions of the donor communication unit 110D. The storage unit 172 is configured by a memory, for example, and stores various kinds of information used for control by the donor communication unit 110D and the like. The I / F unit 173 is connected to the remote communication unit 11OR. The indicator 174 is controlled by the control unit 130D to display the information of the reception level from the radio base station 200.

The remote communication unit 110R owns the remote transmission / reception unit 120R (second transmission / reception unit), the control unit 130R, the storage unit 132, and the I / F unit 133. The remote transmission / reception unit 120R executes remote transmission / reception (second transmission / reception) for transmitting / receiving data with the wireless terminal 300 in accordance with OFDM / OFDMA and TDD schemes. Specifically, the remote transmission / reception unit 120R includes a remote antenna 121, a transmission / reception switch 122, a PA 123, an LNA 124, and an RF / BB unit 125.

The control unit 130R is configured of, for example, a CPU to control various functions of the remote communication unit 110R. The storage unit 132 is configured by a memory, for example, and stores various types of information used for control and the like by the remote communication unit 110R. The I / F unit 133 is connected to the donor communication unit 110D.

In this embodiment, the control unit 130D, 130R constitutes a control unit for controlling donor transmission and reception and remote transmission and reception. The control units 130D and 130R alternately perform the first control and the second control. The first control stops the remote transmission and reception while executing donor transmission and reception in at least one communication frame period, while the second control causes the remote transmission and reception while simultaneously stopping donor transmission and reception in the at least one communication frame period.

The control unit 130R includes a timing shift unit 131. The timing shift unit 131 shifts the timing at which the remote transceiver unit 120R transmits the preamble to the radio terminal 300 before the start timing tO of the communication frame period on the time axis (see FIG. 5). The preamble is used for setting and maintaining synchronization between the wireless relay device 100 and the wireless terminal 300.

(3) Schematic operation of the radio repeater

Next, a schematic operation of the wireless relay device 100 will be described. 4 is a time chart for explaining the schematic operation of the wireless relay apparatus 100.

4A to 4D show a method in which the radio base station 200, the radio relay apparatus 100, and the radio terminal 300 communicate in a conventional manner. 4 (a ') to 4 (d') show how the wireless base station 200, the wireless relay device 100, and the wireless terminal 300 communicate according to the method of the present embodiment.

4 (a) and 4 (a ') show the operation in the wireless base station 200, and FIGS. 4 (b) and 4 (b') show the donor transceiver 12OD of the wireless relay device 100. FIG. 4 (c) and 4 (c ') show the operation of the remote transceiver 120R of the wireless relay device 100, and FIGS. 4 (d) and 4 (d') show the wireless operation. The operation of the terminal 300 is shown.

As shown in Figs. 4A to 4D, in each communication frame period Tn, the downlink subframe period t1 and the uplink subframe period t2 are provided by time division. As shown in FIG. 4 (b), the donor transceiver 120D of the wireless relay device 100 receives data from the wireless base station 200 during the downlink subframe period t1, and the uplink subframe period. Data is transmitted to the wireless base station 200 during t2.

In the conventional system, as shown in FIG. 4C, the remote transceiver 120R of the radio relay apparatus 100 transmits data to the radio terminal 300 during the downlink subframe period t1, Data is received from the wireless terminal 300 during the link subframe period t2. Accordingly, the remote transceiver 120R interferes with the donor transceiver 120D during the downlink subframe period t1, and the donor transceiver 120D receives the remote transceiver 120R during the uplink subframe period t2. ) Interferes with

On the other hand, in the present embodiment, as shown in Figs. 4B 'and 4C, the controllers 130D and 130R perform a donor transmission and reception during the two communication frame periods and simultaneously stop the remote transmission and reception. The second control is executed to stop the donor transmission and reception while executing the remote transmission and reception during the two communication frame periods.

In the examples of FIGS. 4B and 4C, the controllers 130D and 130R execute the first control during the communication frame periods T1 and T2, and during the communication frame periods T3 and T4. The second control is being executed. For example, the radio relay apparatus 100 receives data received from the radio base station 200 during the downlink subframe period t1 of the communication frame period T1 and downlink subframe of the communication frame period T3. It transmits to the wireless terminal 300 in period t1. Thus, data is held in the storage unit 132 or the storage unit 172 in the period of T1 to T3.

In addition, although the 1st control and the 2nd control are changed for every two communication frames, this invention is not limited to this, The 1st control and 2nd control are changed for every communication frame period, or every 3 or more communication frames are changed. The first control and the second control can be switched.

(4) the operation of the wireless communication system

Next, the operation of the wireless communication system 1 will be described with reference to FIGS. 5 and 6.

5 is a time chart for explaining the operation of the wireless communication system 1. As shown in FIG. 5, the timing shift unit 131 of the radio relay apparatus 100 transmits the timing at which the remote transceiver unit 120R transmits the preamble to the radio terminal 300 at the start timing tO of the communication frame period. Shift before). The preamble corresponds to the head symbol of the communication frame and is used for setting and maintaining synchronization between the radio relay apparatus 100 and the radio terminal 300.

The timing shift unit 131 also shifts the frame control header FCH and the MAP following the preamble to a point before the start timing tO. FCH and MAP correspond to two symbols following a preamble. As a result, a total of three symbols including the preamble, the FCH, and the MAP are shifted. By such shift processing, even when remote transmission and reception are stopped by the first control during a specific communication frame period, the preamble, FCH and MAP can be transmitted to the wireless terminal 300 before stopping the remote transmission and reception.

In Fig. 5, the first control is executed during the communication periods T1 and T2, the second control is executed during the communication periods T3 and T4, the first control is executed during the communication periods T5 and T6, and the communication is performed. The second control is also executed in the periods T7 and T8. Therefore, since normal operation and stop of donor transmission / reception are changed every two communication frame intervals, transmission / reception is performed intermittently (hereinafter referred to as intermittent transmission / reception). Similarly, since normal operations and stops of remote transmission and reception are changed at intervals of two communication frames, intermittent transmission and reception are performed.

When stopping the remote transmission / reception, the control unit 130R of the wireless relay device 100 uses the remote transmission / reception unit 120R to generate a MAP indicating that data to be transmitted / received from the wireless terminal 300 does not exist. Exchange for 300). Thus, data transmission and reception by the wireless terminal 30O can be stopped during the communication frame periods T1, T2, T5, and T6. As described above, the timing shifting unit 131 is shifting the MAP before the start timing tO, so that the MAP can be transmitted to the wireless terminal 300 before stopping remote transmission and reception.

When the donor transmission / reception is stopped, the control unit 130D of the wireless relay device 100 stops the donor transmission / reception using the scanning structure. Scanning is usually an operation in which a radio terminal searches for a radio base station of a handover destination, intermittently stops radio communication with the radio base station, and receives a signal from another radio base station in the meantime. However, in this embodiment, as long as data transmission and reception at the radio base station 200 is stopped, the donor communication unit 110D does not need to actually receive a signal at another radio base station. Thus, donor transmission and reception can be stopped during the communication frame periods T3, T4, T7, and T8.

6 is a diagram for explaining a scanning process. The radio relay apparatus 100 exchanges a message for starting scanning with the radio base station 200 before starting intermittent transmission reception as shown in FIG. Specifically, the donor communication unit 110D of the radio relay 100 transmits the SCN-REQ requesting scanning to the radio base station 200. The SCN-REQ includes information indicating the timing at which scanning is started, information indicating the period during which scanning is performed, and information indicating the time interval at which scanning is executed within the period.

If the SCN-REQ is allowed, the radio base station 200 transmits a response SCN-RSP (permission) indicating the permission to the radio relay apparatus 100. During such negotiation, the remote communication unit 11OR of the wireless relay device 100 stops remote transmission and reception using MAP. Upon receiving the SCN-RSP (permission) from the wireless base station 200, the donor communication unit 110D notifies the remote communication unit 110R of the start timing of scanning, the scanning period, and the like, and the intermittent transmission and reception starts as shown in FIG. . On the other hand, after the elapse of the scanning period, another negotiation for starting the next scanning is executed, and the next scanning is started.

(5) Action / effect

As described above, the controllers 130D and 130R execute first control for executing donor transmission and reception and stopping remote transmission and reception for at least one communication frame period. Therefore, during the communication frame period, the radio waves radiated from the donor transceiver 120D can be prevented from interfering with the remote transceiver 120R.

Similarly, the controllers 130D and 130R execute second control for stopping donor transmission and reception and operating remote transmission and reception for at least one communication frame period. Therefore, during the communication frame period, it is possible to prevent the radio waves radiated from the remote transceiver 120R from interfering with the donor transceiver 120D.

In addition, the control units 130D and 130R can continue the data relay more reliably while avoiding the interference by alternately executing the first control and the second control.

In addition, since only the controllers 130D and 130R are required to control whether or not each of the donor transmission and reception and the remote transmission and reception are executed, it is not necessary to change the communication frequency and the size of the radio relay apparatus 100. And increase in cost can be suppressed.

In the present embodiment, the timing shift unit 131 of the control unit 130R transmits the timing at which the remote transceiver unit 120R transmits the preamble to the wireless terminal 300 on the time axis at the start timing tO of the communication frame period. Shift to the front.

As a result, even when the remote transmission / reception is stopped by the first control during the specific communication frame period, the preamble can be transmitted to the wireless terminal 300 before the remote transmission / reception is stopped. Therefore, step-out between the wireless relay device 100 and the wireless terminal 300 can be prevented. Therefore, interference can be prevented while maintaining synchronization between the wireless relay device 100 and the wireless terminal 300.

In the present embodiment, the controllers 130D and 130R stop remote transmission and reception using a MAP defined by WiMAX, and stop donor transmission and reception using scanning specified by WiMAX. Thus, intermittent transmission and reception are realized within an existing frame in WiMAX.

(6) Other Examples

As mentioned above, the details of the present invention have been described using the examples of the present invention. However, it should not be understood that the description and drawings which form part of this disclosure limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques are readily discovered by those skilled in the art.

In the above-described embodiment, the wireless relay device 100 is executing data relay between the wireless base station 200 and the wireless terminal 300. However, when the two wireless terminals 300 communicate with each other according to the TDD scheme, the wireless relay device 100 can relay data exchanged between these wireless terminals 300. Alternatively, when the plurality of radio relay devices 100 relay data between the radio base station 200 and the radio terminal 300, the radio relay device 100 exchanges between other radio relay devices 100. You can relay the data.

In addition, in the above-described embodiment, the wireless communication system 1 according to WiMAX (IEEE802.16) has been described, but the present invention is not limited to WiMAX, and it is only necessary that the wireless communication system uses the TDD scheme. Therefore, the present invention is also applicable to, for example, the next generation PHS, iBurst (registered trademark) system and the like.

As described above, the present invention typically includes various embodiments not described herein. Accordingly, the technical scope of the present invention is limited only by the invention specific matters of the claims deemed appropriate from this disclosure.

The entire contents of Japanese Patent Application No. 2008-235926 (filed September 16, 2008) are incorporated in the present specification by reference.

[Industrial Availability]

As described above, according to the radio relay apparatus and radio relay method according to the present invention, data relay can be continued while avoiding the influence of the interference in the radio relay apparatus without changing the communication frequency, thereby suppressing the increase in size and cost. can do. Thus, the present invention is useful in the field of wireless communication such as mobile communication.

Claims (6)

In each communication timeframe divided on the time axis, a first period of transmitting data from the first wireless communication device to the second wireless communication device and a data transmission from the second wireless communication device to the first wireless communication device. In a wireless communication system in which two periods are provided in time division, a wireless relay device for relaying data transmitted and received by the first wireless communication device and the second wireless communication device,
A first transmission / reception unit configured to receive data from the first radio communication device in the first period and to perform first transmission / reception to transmit data to the first radio communication device in the second period;
A second transmission / reception unit configured to transmit data to the second wireless communication device in the first period, and perform second transmission / reception to receive data from the second wireless communication device in the second period; and
A control unit for controlling the first transmission and reception and the second transmission and reception;
The control unit may include: first control to execute the first transmission / reception and stop the second transmission / reception for at least one communication time frame, and to stop the first transmission / reception and to execute the second transmission / reception for at least one communication time frame. A wireless relay device for performing a second control to make. The method according to claim 1,
The control unit performs the wireless control device alternately performing the first control and the second control. The method according to claim 1 or 2,
The second transceiver transmits, to the second radio communication device, synchronization information used for setting and maintaining synchronization between the radio relay device and the second radio communication device.
And the control unit shifts the timing at which the second transmission / reception unit transmits the synchronization information to the second wireless communication device to a point before the start timing of the communication time frame on a time axis. The method according to claim 1,
And wireless communication in accordance with orthogonal frequency division multiplexing is executed in the wireless communication system. The method according to claim 1,
And the first wireless communication device is a wireless base station, and the second wireless communication device is a wireless terminal. In each communication timeframe divided on the time axis, a first period of transmitting data from the first wireless communication device to the second wireless communication device and a data transmission from the second wireless communication device to the first wireless communication device. A radio relay method used in a radio relay apparatus for relaying data transmitted and received by the first radio communication apparatus and the second radio communication apparatus in a radio communication system in which two periods are provided by time division,
First transmission and reception for receiving data from the first radio communication device in the first period and transmitting data to the first radio communication device in the second period, and data to the second radio communication device in the first period. Controlling a second transmission / reception of transmitting a signal and receiving data from the second wireless communication device in the second period of time,
In the controlling step, a first control is executed for executing the first transmission / reception and stopping the second transmission / reception for at least one communication time frame, and stopping the first transmission / reception and the second for at least one communication time frame. And a second control for executing transmission and reception.

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