JP4794664B2 - Radio relay apparatus and radio relay method - Google Patents

Description

  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 a time division duplex system.

  Conventionally, a wireless relay device that relays data transmitted and received between a first wireless communication device such as a wireless base station and a second wireless communication device such as a wireless terminal has been widely used (see, for example, Patent Document 1). Such a wireless relay device includes a first transmission / reception unit that transmits / receives data to / from the first wireless communication device, and a second transmission / reception unit that transmits / receives data to / from the second wireless communication device.

  In addition, a time division duplex (TDD) method is known as one method for realizing bidirectional communication in a wireless communication system. In the TDD scheme, data is transmitted from the first wireless communication apparatus to the first wireless communication apparatus during a first period (for example, a downlink frame) in which data is transmitted from the first wireless communication apparatus to the second wireless communication apparatus. The second period (for example, uplink frame) is provided in a time division manner for each communication time frame (communication frame) divided on the time axis.

  When a wireless relay device is used in a wireless communication system that employs the TDD scheme, the second transmitter / receiver receives data from the first wireless communication device at the same time as the first transmitter / receiver receives data from the first wireless communication device in the first period. Send to device. Similarly, at the same time that the second transmitter / receiver receives data from the second wireless communication device in the second period, the first transmitter / receiver transmits data to the first wireless communication device.

  For this reason, the radio wave radiated from the antenna of the second transmission / reception unit during the first period goes around the antenna of the first transmission / reception unit, and the radio wave radiated from the antenna of the first transmission / reception unit during the second period is the antenna of the second transmission / reception unit. Go around. It has been regarded as a problem that the first transmitter / receiver and the second transmitter / receiver are affected by interference due to such wraparound.

  JP 2008-67386 A ([Summary] etc.)

  In order to avoid the influence of the interference as described above, any one of the following methods (a) to (c) can be considered. (A) The arrangement | positioning space | interval of each antenna of a 1st transmission / reception part and a 2nd transmission / reception part is taken large, or an electromagnetic wave shielding board is arrange | positioned between antennas. (B) Introduce advanced signal processing technology to remove the influence of interference. (B) Increase the interval between the communication frequencies of the first transmission / reception unit and the second transmission / reception unit.

  However, the methods (a) and (b) have a problem that the size and cost of the wireless relay device increase. In the method (c), a communication frequency that can be used by the wireless relay device is determined in advance, and there is a problem that it is difficult to change the communication frequency.

  Therefore, the present invention avoids the influence of interference between the first transmission / reception unit and the second transmission / reception unit without changing the communication frequency, and suppresses an increase in size and cost and a wireless relay device It aims to provide a method.

In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that a first period (eg, a downlink sub-transmission) in which data transmission from a first radio communication device (eg, radio base station 200) to a second radio communication device (eg, radio terminal 300) is executed. A communication time in which a frame period t1) and a second period in which data transmission from the second wireless communication apparatus to the first wireless communication apparatus is executed (for example, an uplink subframe period t2) are divided on the time axis In a wireless communication system (wireless communication system 1) provided in a time-sharing manner for each frame (communication frame period Tn), a wireless relay device (wireless) that relays data transmitted and received by the first wireless communication device and the second wireless communication device Relay device 100) 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 first transmission / reception unit (donor-side transmission / reception unit 120D), a second transmission / reception unit (remote-side transmission / reception unit 120R) that transmits data to the second wireless communication device and receives data from the second wireless communication device; A control unit (control unit 130R) that controls the second transmission / reception unit, wherein the control unit sets a reception period in which the second transmission / reception unit receives data from the second wireless communication apparatus as the first period. and, wherein the transmission period in which the second transceiver transmits data to the second wireless communication device (remote-side transmission period P1) set to the second period, the time length of the first period, the second period Is longer than the time length, and the control unit sets the transmission period to the second period, so that part of the transmission period (overlapping portion Δt) exceeds the second period on the time axis. Overlap with part of the first period The gist is that the control unit stops data transmission from the second transmitting / receiving unit to the second wireless communication device in a part of the transmission period (overlapping portion Δt) overlapping the first period.

  According to such a wireless relay device, the control unit radiates from the second transmission / reception unit in the first period because the second transmission / reception unit sets the transmission period for transmitting data to the second wireless communication device to the second period. It is possible to avoid the radio wave that has been interfered with the first transmission / reception unit. In addition, since it is only necessary to change the transmission period, it is not necessary to change the communication frequency, and the size and cost of the wireless relay device are increased as compared with the methods (a) and (b). Can be suppressed.

  A second feature of the present invention relates to the first feature of the present invention, wherein the control unit sets a reception period in which the second transceiver receives data from the second wireless communication device as the first period. The gist is to do.

  A third feature of the present invention relates to any one of the first and second features of the present invention, and is a frequency band (for example, 30 MHz) that the first transmitter / receiver and the second transmitter / receiver can use for wireless communication. Is divided into at least three communication frequencies, the three communication frequencies being a first communication frequency (communication frequency F1), a second communication frequency (communication frequency F2), and the first communication frequency and the second communication frequency. The first transmission / reception unit wirelessly communicates with the first wireless communication device using the first communication frequency without using the third communication frequency. The gist is that communication is performed, and the second transmission / reception unit performs wireless communication with the second wireless communication device using the second communication frequency without using the third communication frequency.

  A fourth feature of the present invention relates to any one of the first to third features of the present invention, wherein the first wireless communication device is a wireless base station (wireless base station 200), and the second wireless communication device The gist of the communication device is a wireless terminal (wireless terminal 300).

A fifth feature of the present invention is that a first period in which data transmission from the first wireless communication apparatus to the second wireless communication apparatus is executed, and data transmission from the second wireless communication apparatus to the first wireless communication apparatus. In a wireless communication system provided in a time-sharing manner in each communication time frame divided on the time axis, data transmitted and received by the first wireless communication device and the second wireless communication device A radio relay method used in a radio relay apparatus for relaying, wherein a first transmitter / receiver receives data from the first radio communication apparatus in the first period and transmits data to the first radio communication apparatus in the second period. A step of transmitting data; and a step of transmitting data to the second wireless communication device and controlling a second transmission / reception unit for receiving data from the second wireless communication device. Is a transmission period in which the second transceiver sets the reception period for receiving data from the second wireless communication device to the first period, the second transceiver transmits data to the second wireless communication device The step of setting in the second period and the time length of the first period are longer than the time length of the second period, and the control unit sets the transmission period to the second period, so that the transmission A part of the period (overlapping part Δt) overlaps with the part of the first period over the second period on the time axis, and the control unit includes a part of the transmission period that overlaps with the first period. (Overlapping portion Δt) includes a step of stopping data transmission from the second transceiver to the second wireless communication device.

  According to the present invention, a radio relay apparatus and a radio relay that avoid the influence of interference between the first transmission / reception unit and the second transmission / reception unit without changing the communication frequency, and suppress the increase in size and cost. Can provide a method.

1 is a schematic configuration diagram of a radio communication system according to an embodiment of the present invention. It is a functional block block diagram of the radio relay apparatus concerning embodiment of this invention. It is a schematic perspective view which shows the example of mounting of the radio relay apparatus concerning embodiment of this invention. It is a time chart for demonstrating schematic operation | movement of the radio relay apparatus which concerns on embodiment of this invention. It is a communication frame block diagram for demonstrating detailed operation | movement of the radio relay apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the modification 1 of embodiment of this invention. It is a figure for demonstrating the modification 2 of embodiment of this invention.

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

(1) Schematic Configuration of Radio Communication System FIG. 1 is a schematic configuration diagram of a radio communication system 1 according to the present embodiment.

  As illustrated in FIG. 1, the wireless communication system 1 includes a wireless relay device 100, a wireless base station 200, and a wireless terminal 300. The wireless communication system 1 has a configuration based on WiMAX (IEEE802.16). That is, the radio communication system 1 employs an orthogonal frequency division multiple access (OFDMA) system and a time division duplex (TDD) system.

  The OFDMA scheme realizes multiple connections using a number of subcarriers orthogonal to each other. The TDD scheme realizes bidirectional communication by executing uplink communication and downlink communication in a time division manner within one communication frame (communication time frame). “Uplink direction (uplink)” means a direction from radio terminal 300 to radio base station 200, and “downlink (downlink)” means a direction from radio base station 200 to radio terminal 300. Means.

  In WiMAX, first, downlink communication is executed in a communication frame, and then uplink communication is executed. In the following, a period in which downlink communication is performed in a communication frame is referred to as a “downlink subframe period (first period)”, and a period in which uplink communication is performed in a communication frame is referred to as an “uplink subframe period ( 2nd period) ". Since downlink communication requires a larger communication capacity than uplink communication, the time length of the downlink subframe period is longer than the time length of the uplink subframe period (see FIG. 5).

  The radio relay apparatus 100 relays data transmitted and received by the radio base station 200 and the radio terminal 300. As a result, the radio terminal 300 can communicate with the radio base station 200 even if the radio terminal 300 is located outside the range of the cell (communication area) formed by the radio base station 200 or located in the peripheral portion (so-called self-ringing) of the cell. . In the example of FIG. 1, the wireless relay device 100 is installed in the home H, and performs wireless communication with the wireless terminal 300 located in the home H. Such a wireless relay device 100 is required to be small and inexpensive.

(2) Configuration of Radio Relay Device Next, the configuration of the radio relay device 100 will be described in the order of (2.1) functional block configuration and (2.2) implementation example.

(2.1) Functional Block Configuration FIG. 2 is a block diagram showing a functional block configuration of the wireless relay device 100.

  As illustrated in FIG. 2, the radio relay device 100 includes a donor-side communication unit 110 </ b> D that communicates with the radio base station 200 and a remote-side communication unit 110 </ b> R that communicates with the radio terminal 300. The donor-side communication unit 110D has a communication function equivalent to that of a radio terminal, and the remote-side communication unit 110R has a communication function equivalent to that of a radio base station. The donor-side communication unit 110D and the remote-side communication unit 110R are connected by wire using Ethernet (registered trademark) or the like.

  The donor-side communication unit 110D includes a donor-side transmission / reception unit 120D (first transmission / reception unit), a control unit 130D, a storage unit 172, an interface (I / F) unit 173, and an indicator 174. The donor-side transmitting / receiving unit 120D transmits / receives data to / from the radio base station 200 using the OFDMA / TDD scheme. Specifically, the donor-side transceiver unit 120D includes donor antennas 161a and 161b, transmission / reception changeover switches 162a and 162b, power amplifiers (PA) 163a and 163b, low-noise amplifiers (LNA) 164a and 164b, and high frequency / baseband (RF). / BB) portions 165a and 165b. Thus, in the present embodiment, the diversity effect is obtained by providing two transmission / reception systems in the donor-side transmission / reception unit 120D. The control unit 130D includes, for example, a CPU and controls various functions provided in the donor-side communication unit 110D. The storage unit 172 includes, for example, a memory, and stores various types of information used for control in the donor-side communication unit 110D. The I / F unit 173 is connected to the remote communication unit 110R. The indicator 174 is controlled by the control unit 130D and displays information indicating the reception level from the radio base station 200.

  The remote communication unit 110R includes a remote transmission / reception unit 120R (second transmission / reception unit), a control unit 130R (control unit), a storage unit 132, and an I / F unit 133. The remote transmission / reception unit 120R transmits / receives data to / from the wireless terminal 300 using the OFDMA / TDD scheme. Specifically, the remote transmission / reception unit 120R includes remote antennas 121a and 121b, transmission / reception changeover switches 122a and 122b, PAs 123a and 123b, LNAs 124a and 124b, and RF / BB units 125a and 125b. Thus, in the present embodiment, the diversity effect is obtained by providing two transmission / reception systems in the remote-side transmission / reception unit 120R. The control unit 130R includes, for example, a CPU and controls various functions provided in 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 in the remote communication unit 110R. The I / F unit 133 is connected to the donor-side communication unit 110D.

(2.2) Mounting Example FIG. 3 is a schematic perspective view illustrating a mounting example of the wireless relay device 100.

  As shown in FIGS. 3A and 3B, a substrate 101 on which the donor-side communication unit 110D is mounted and a remote-side communication unit 110R are mounted in the housing 105 of the wireless relay device 100. A substrate 103 and a substrate 102 on which a relay mechanism between the donor-side communication unit 110D and the remote-side communication unit 110R is mounted are provided. Donor antennas 161 a and 161 b extend from the substrate 101 to the outside of the housing 105. The remote antennas 121a and 121b are disposed on the substrate 103. In this way, in the radio relay device 100, the donor antennas 161a and 161b and the remote antennas 121a and 121b are arranged close to each other without providing a radio wave shielding plate.

(3) Operation of Radio Relay Device Next, the operation of the radio relay device 100 will be described in the order of (3.1) general operation and (3.2) detailed operation.

(3.1) Schematic Operation FIG. 4 is a time chart for explaining the schematic operation of the wireless relay device 100.

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

  4 (a) and 4 (a ′) show the operation in radio base station 200, and FIGS. 4 (b) and 4 (b ′) show the operation in donor-side transceiver 120D of radio relay apparatus 100. 4 (c) and FIG. 4 (c ′) show the operation in the remote transmitting / receiving unit 120R of the wireless relay device 100, and FIG. 4 (d) and FIG. 4 (d ′) show the operation in the wireless terminal 300. ing.

  As shown in FIGS. 4A to 4D, in each communication frame period Tn, a downlink subframe period t1 and an uplink subframe period t2 are provided in a time division manner. As shown in FIG. 4B, the donor-side transceiver unit 120D of the radio relay apparatus 100 receives data from the radio base station 200 in the downlink subframe period t1, and transmits data to the radio base station 200 in the uplink subframe period t2. Send. In the conventional scheme, as shown in FIG. 4C, the remote transmitting / receiving unit 120R of the radio relay device 100 transmits data to the radio terminal 300 in the downlink subframe period t1, and the radio terminal 300 in the uplink subframe period t2. Receive data from. For this reason, the remote transceiver 120R interferes with the donor transceiver 120D during the downlink subframe period t1, and the donor transceiver 120D interferes with the remote transceiver 120R during the uplink subframe period t2.

  On the other hand, in the present embodiment, as shown in FIG. 4C ′, the control unit 130R of the remote side communication unit 110R sets the remote side transmission period P1 during which the remote side transmission / reception unit 120R transmits data to the wireless terminal 300 as the uplink sub Set to frame period t2. In addition, the control unit 130R sets the remote reception period P2 in which the remote transmission / reception unit 120R receives data from the wireless terminal 300 as the downlink subframe period t1.

  For example, as shown in FIGS. 4 (a ′) to 4 (d ′), the wireless relay device 100 transmits data received from the wireless terminal 300 in the downlink subframe period t1 of the communication frame period T1 to the communication frame period T1. Is transmitted to the radio base station 200 in the uplink subframe period t2. Radio relay apparatus 100 transmits data received from radio base station 200 in downlink subframe period t1 of communication frame period T1 to radio terminal 300 in uplink subframe period t2 of communication frame period T1. This avoids the interference described above.

  However, the time length of the downlink subframe period t1 is longer than the time length of the uplink subframe period t2. Therefore, when the control unit 130R sets the remote-side transmission period P1 to the uplink subframe period t2, a part of the remote-side transmission period P1 exceeds the uplink subframe period t2 and overlaps a part of the downlink subframe period t1. . Hereinafter, a part of the remote-side transmission period P1 that overlaps the downlink subframe period t1 is referred to as an overlapping portion Δt. In the overlapping portion Δt, the remote transmitting / receiving unit 120R interferes with the donor transmitting / receiving unit 120D. Therefore, the control unit 130R stops data transmission from the remote transmitting / receiving unit 120R to the wireless terminal 300 in the overlapping portion Δt. Thereby, interference in the overlapping portion Δt can also be avoided.

(3.2) Detailed Operation Next, detailed operation of the wireless relay device 100 will be described. FIG. 5 is a communication frame configuration diagram for explaining the detailed operation of the radio relay apparatus 100.

  As shown in FIG. 5A, the communication frame FR in WiMAX includes a downlink subframe SFR1 and an uplink subframe SFR2. The downlink subframe SFR1 and the uplink subframe SFR2 are each composed of a plurality of symbols. The head of the downlink subframe SFR1 is a control data area in which various control data are arranged, and thereafter a burst area in which communication data (user data) is arranged. The control data includes a preamble that is a known symbol, an FCH (header information transmitted from the radio base station), and a MAP that is allocation information regarding uplink and downlink burst signals. The remote-side transmitting / receiving unit 120R of the wireless relay device 100 transmits the downlink subframe SFR1 during the remote-side transmission period P1, and receives the uplink subframe SFR2 during the remote-side reception period P2. Note that a guard time (TTG) is provided between the downlink subframe SFR1 and the uplink subframe SFR2.

  As shown in FIG. 5B, in the overlapping portion Δt (see FIG. 4) in the remote transmission period P1, the remote transmission / reception unit 120R of the wireless relay device 100 stops transmission of the downlink subframe SFR1. For this reason, data to be transmitted is not transmitted in the overlapping portion Δt, but the data can be transmitted to the wireless terminal 300 by using a mechanism such as retransmission control. It is preferable to arrange data in which communication delay is allowed in the overlapping part Δt, and it is preferable not to arrange data having high real-time characteristics and required service quality (QoS) such as voice data in the overlapping part Δt.

(4) Operation / Effect As described above, the control unit 130R sets the remote transmission period P1 from the downlink subframe period t1 to the uplink subframe period t2, and thus the remote transmission / reception unit 120R in the downlink subframe period t1. It can be avoided that the radio wave radiated from interferes with the donor-side transmitting / receiving unit 120D. In addition, since the control unit 130R sets the remote reception period P2 from the uplink subframe period t2 to the downlink subframe period t1, the radio wave radiated from the donor-side transmission / reception unit 120D in the uplink subframe period t2 It is possible to avoid giving interference to 120R. Furthermore, since it is only necessary to change the remote-side transmission period P1 and the remote-side reception period P2, it is not necessary to change the communication frequency, and an increase in the size and cost of the wireless relay device 100 can be suppressed. Therefore, according to the present embodiment, a small and inexpensive wireless relay device 100 can be provided.

  In the present embodiment, the control unit 130R stops data transmission from the remote-side transmission / reception unit 120R to the wireless terminal 300 at the overlapping portion Δt. Thereby, even if it is the radio | wireless communications system 1 which employ | adopts an uplink / downlink asymmetric frame structure, the influence of interference can be avoided reliably.

(5) Other Embodiments As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

(5.1) Modification 1
The radio relay apparatus 100 is often installed in the self-ringe of the radio base station 200, and radio waves from the radio base station 200 may not normally reach the radio relay apparatus 100 depending on the installation location of the radio relay apparatus 100. . In such a case, the wireless relay device 100 cannot execute data relay.

  Therefore, in the first modification, as shown in FIG. 6, even when the external antenna unit 190 can be connected to the wireless relay device 100 and the radio wave from the wireless base station 200 does not reach the wireless relay device 100 normally, the data Enable relaying.

  The wireless relay device 100 according to the first modification has a connection terminal to which a cable from the external antenna unit 190 is attached and detached. When the control unit 130D detects that the cable is connected to the connection terminal, the control unit 130D automatically switches the transmission / reception system from the donor-side transmission / reception unit 120D to the external antenna unit 190.

(5.2) Modification 2
As described above, in the wireless communication system 1, the frequency band that can be used by the donor-side transceiver 120D and the remote-side transceiver 120R for wireless communication is determined in advance. As shown in FIG. 7, for example, a frequency band of 30 MHz can be used, and the frequency band is equally divided into three communication frequencies F1 to F3.

  In the second modification, the donor-side transmitting / receiving unit 120D performs radio communication with the radio base station 200 using the communication frequency F1 without using the central communication frequency F3. The remote transmitting / receiving unit 120R performs wireless communication with the wireless terminal 300 using the communication frequency F2 without using the central communication frequency F3. Thereby, the interval of the communication frequency which each of the remote side transmission / reception part 120R and donor side transmission / reception part 120D utilizes is ensured, and the influence of interference is further reduced.

(5.3) Other Application Examples In the embodiment described above, the radio relay apparatus 100 performs data relay between the radio base station 200 and the radio terminal 300. However, when two wireless terminals 300 communicate with each other using the TDD scheme, the wireless relay device 100 may relay data transmitted and received between these wireless terminals 300. Alternatively, when a plurality of radio relay apparatuses 100 perform data relay between the radio base station 200 and the radio terminal 300, the radio relay apparatus 100 relays data transmitted and received between other radio relay apparatuses 100. May be.

  In the above-described embodiment, the wireless communication system 1 based on WiMAX (IEEE802.16) has been described. The present invention can also be applied to a registered trademark system.

  Furthermore, the wireless relay device 100 is not limited to a fixed type, and may be a mobile type mounted on a vehicle, for example.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 100 ... Wireless relay apparatus, 101-103 ... Board | substrate, 105 ... Housing | casing, 110D ... Donor side communication unit, 110R ... Remote side communication unit, 120D ... Donor side transmission / reception part, 120R ... Remote side transmission / reception part 121a, 121b ... remote antenna, 122a, 122b, 162a, 162b ... transmission / reception selector switch, 123a, 123b, 163a, 163b ... PA, 124a, 124b, 164a, 164b ... LNA, 125a, 125b, 165a, 165b ... RF / BB unit, 130D, 130R ... control unit, 132,172 ... storage unit, 133,173 ... I / F unit, 161a, 161b ... donor antenna, 174 ... indicator, 190 ... external antenna unit, 200 ... radio base station, 300 ... Wireless terminal

Claims (4)

A first period in which data transmission from the first wireless communication apparatus to the second wireless communication apparatus is executed, and a second period in which data transmission from the second wireless communication apparatus to the first wireless communication apparatus is executed. A wireless relay device that relays data transmitted and received by the first wireless communication device and the second wireless communication device in a wireless communication system provided in a time division manner in each communication time frame divided on the time axis,
A first transceiver 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 transceiver for transmitting data to the second wireless communication device and receiving data from the second wireless communication device;
A control unit for controlling the second transmission / reception unit,
The control unit sets a reception period during which the second transmission / reception unit receives data from the second wireless communication device to the first period, and the second transmission / reception unit transmits data to the second wireless communication device. Set the transmission period to the second period,
The time length of the first period is longer than the time length of the second period,
Since the control unit sets the transmission period to the second period, a part of the transmission period overlaps a part of the first period over the second period on the time axis,
The said control part is a radio relay apparatus which stops the data transmission from the said 2nd transmission / reception part to the said 2nd radio | wireless communication apparatus in a part of said transmission period which overlaps with the said 1st period. The frequency band that can be used for wireless communication by the first transmitter / receiver and the second transmitter / receiver is divided into at least three communication frequencies,
The three communication frequencies consist of a first communication frequency, a second communication frequency, and a third communication frequency between the first communication frequency and the second communication frequency,
The first transmission / reception unit performs wireless communication with the first wireless communication device using the first communication frequency without using the third communication frequency,
The wireless relay device according to claim 1, wherein the second transmission / reception unit performs wireless communication with the second wireless communication device using the second communication frequency without using the third communication frequency. The first radio communication device is a wireless base station, the second radio communication apparatus, the radio relay apparatus according to claim 1 or 2 which is a wireless terminal. A first period in which data transmission from the first wireless communication apparatus to the second wireless communication apparatus is executed, and a second period in which data transmission from the second wireless communication apparatus to the first wireless communication apparatus is executed. In a wireless communication system provided in a time-sharing manner for each communication time frame divided on the time axis, wireless used for a wireless relay device that relays data transmitted and received by the first wireless communication device and the second wireless communication device A relay method,
A step of 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;
Transmitting data to the second wireless communication device and controlling a second transmitting / receiving unit for receiving data from the second wireless communication device,
The controlling step sets a reception period in which the second transmission / reception unit receives data from the second wireless communication device to the first period, and the second transmission / reception unit transmits data to the second wireless communication device. Setting the transmission period to be the second period;
The time length of the first period is longer than the time length of the second period,
Since the control unit sets the transmission period to the second period, a part of the transmission period overlaps a part of the first period over the second period on the time axis,
The control unit includes a step of stopping data transmission from the second transmission / reception unit to the second wireless communication device in a part of the transmission period overlapping the first period.