JP2011024143A - Radio relay device, frame structure, method for controlling the same and radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a radio relay device which can solve problems in a regular rotation system without disposing a communication part for a base station and a communication part for a terminal station to separate from each other. <P>SOLUTION: A storage part 31 stores information about frequency channels used by each of one or more radio waves received by an antenna 6X for a base station from one or more base stations so that the information is associated with the one or more base stations. A control part 30 selects either a first communication system or a second communication system on the basis of the information stored in the storage part 31: the first communication system for causing the communication part 20 for a terminal station to perform a reception operation during a period when the communication part 10 for a base station performs a reception operation and causing the communication part 20 for a terminal station to perform a transmission operation during a period when the communication part 10 for a base station performs a transmission operation; and the second communication system for causing the communication part 20 for a terminal station to perform both the reception operation and transmission operation during the period when the communication part 10 for a base station performs the reception operation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radio relay device that relays radio communication between a base station and a terminal station, a frame structure, a control method for the radio relay device, and a radio communication system including the radio relay device, and more particularly, an outdoor base station and an indoor terminal. The present invention relates to a regenerative indoor repeater that relays wireless communication with a station.

  For example, in a wireless communication system using WiMAX, a communication state between a base station and a terminal station should be ensured even when the terminal station exists in an area where radio waves from the base station are difficult to reach (for example, indoors). A wireless relay device is used.

  The wireless relay device has an antenna for a base station for transmitting / receiving radio waves to / from a base station, and an antenna for a terminal station for transmitting / receiving radio waves to / from a terminal station. The regenerative wireless relay device once demodulates the radio wave from the base station received by the base station antenna, modulates only the necessary signal, amplifies the signal, and then directs the signal from the terminal antenna to the terminal station. Send. In addition, the regenerative wireless relay device once demodulates the radio wave from the terminal station received by the terminal antenna, modulates only the necessary signal, amplifies the signal, and then transmits the signal from the base station antenna to the base station. Send to. In this way, mutual communication between the base station and the terminal station is ensured by way of the wireless relay device.

  Patent Document 1 listed below discloses a PHS communication system including a wireless relay device. The radio relay apparatus includes a base station communication unit connected to the base station antenna and a terminal station communication unit connected to the mobile station antenna. Then, the reception timing of the base station communication unit is matched with the transmission timing of the terminal station communication unit, and the mutual interference between the communication radio wave of the base station communication unit and the communication radio wave of the terminal station communication unit is suppressed. Therefore, the base station communication unit and the terminal station communication unit are arranged apart from each other by wired connection using a cable.

JP 2000-78065 A

  In the wireless relay device corresponding to WiMAX, the transmission timing of the base station communication unit and the reception timing of the terminal station communication unit are matched, and the reception timing of the base station communication unit and the transmission timing of the terminal station communication unit are matched. Is generally a communication method (a normal rotation method described later).

  By the way, in an indoor repeater or the like installed in a general household, if an integrated configuration is to be realized by attaching an antenna for a base station and an antenna for a terminal station to an apparatus housing, the antenna for the base station is inevitably required. And the terminal station antenna approach. For this reason, inter-antenna isolation between the antenna for the base station and the antenna for the terminal station cannot be obtained.

  Therefore, in this case, the transmission radio wave from the antenna for the base station wraps around the antenna for the terminal station, thereby affecting the communication performance between the terminal station communication unit and the terminal station. When the transmitted radio wave wraps around the antenna for the base station, the communication performance between the base station communication unit and the base station is affected.

  By the way, in determining the communicable area of the wireless relay device, the influence of the transmission radio wave from the antenna for the base station on the communication performance between the terminal station communication unit and the terminal station is often dominant. First, it is necessary to take measures against this effect. Here, since the transmission power of the communication unit with respect to the base station is controlled by the base station, it cannot be set freely in the radio relay apparatus. Therefore, in order to suppress the influence of the transmission radio wave from the antenna for the base station on the communication performance between the communication unit for the terminal station and the terminal station, the reception of the communication unit for the terminal station caused by radio wave interference is particularly important. In order to suppress the decrease in sensitivity (in other words, the increase in the minimum reception sensitivity), it is necessary to increase the set value of the reception power of the radio wave transmitted from the terminal station in the terminal station communication unit. This leads to an increase in the transmission power of the terminal station.

  In general, the transmission power of the terminal station is set by the control of the base station. The base station sets the transmission power of the terminal station to an appropriate value in consideration of propagation loss between the base station and the terminal station. As a result, the influence of the transmission radio wave from the terminal station on the base station (peripheral base station) that is not the connection target is avoided.

  However, as described above, the transmission power of the terminal station connected to the radio relay apparatus adopting the normal rotation method is such that the transmission radio wave from the antenna for the base station is in communication performance between the terminal station communication unit and the terminal station. In order to suppress the influence, it is necessary to set a larger value than the appropriate value to be set according to the propagation loss. As a result, the power consumption of the terminal station increases, and there is a high possibility that the transmission radio waves from the terminal stations under the control of the wireless relay device will affect the neighboring base stations and the neighboring terminal stations.

  In addition, in order to suppress the influence of the transmission radio wave from the terminal station antenna on the communication performance between the base station communication unit and the base station, wrap around the radio wave from the terminal antenna to the base station antenna. In order to suppress this, it is necessary to reduce the transmission power of the communication unit with respect to the terminal station. This acts in the direction of narrowing the communicable area of the wireless relay device.

  On the other hand, according to the wireless relay device disclosed in Patent Document 1, the inter-antenna isolation is obtained by disposing the physical distance between the base station communication unit and the terminal station communication unit away from each other. Therefore, it is possible to suppress the above-described problem in the forward rotation method.

  However, according to the wireless relay device disclosed in Patent Document 1, the base station communication unit and the terminal station communication unit need to be spaced apart from each other by wired connection. Therefore, it is necessary to select each installation location of the communication unit with respect to the base station and the communication unit with respect to the terminal station while measuring the degree of mutual interference of the communication radio waves, and the cable is wired between the installation locations of both communication units. Since it is necessary, the installation work becomes complicated and the convenience for the user is low. Moreover, since the housing | casing for storing an anti-base station communication part and the housing | casing for storing an anti-terminal station communication part are needed separately, and a cable is also required, an increase in cost is caused.

  The present invention has been made to solve such a problem, and it is possible to suppress problems in the forward rotation system without arranging the base station communication unit and the terminal station communication unit apart from each other. It is another object of the present invention to obtain a radio relay device, a frame structure, a radio relay device control method, and a radio communication system.

The radio relay apparatus according to the first aspect of the present invention performs communication with a base station using a first frequency channel among a plurality of frequency channels, and also performs second communication among the plurality of frequency channels. A radio relay apparatus that relays communication between the base station and the terminal station by performing communication with the terminal station using a frequency channel of the base station, and transmits and receives radio waves to and from the base station A base station antenna for performing communication, a terminal antenna for transmitting and receiving radio waves to and from the terminal station, a base station communication unit connected to the base station antenna, and the terminal station The one or more terminal station communication unit connected to the antenna and the one or more base station antennas obtained by demodulating one or more radio waves received from one or more base stations by the base station communication unit Used by each of the radio waves A storage unit that stores information relating to the frequency channel being used in association with each of the one or more base stations, and a period during which the communication unit with the base station performs a transmission operation and a period during which a reception operation is performed. And a control unit that controls a period during which the terminal station communication unit performs a transmission operation and a period during which a reception operation is performed, and the control unit stores the information stored in the storage unit. On the basis of the period during which the communication with the base station communication unit performs the reception operation, the mobile communication with the terminal station communication unit performs the reception operation within the period in which the communication with the base station communication unit performs the transmission operation. Receiving the communication with the terminal station communication unit within a period during which the communication with the base station communication unit is performing a reception operation. To perform both operation and transmission operation, It is characterized in that for selecting one of the second communication method.

  Here, the concept of “frequency channel” includes a frequency band (the same applies hereinafter).

  According to the wireless relay device according to the first aspect, the storage unit can be obtained by demodulating one or more radio waves received by the base station antenna from one or more base stations by the base station communication unit. Information regarding the frequency channel used by each of the one or more radio waves is stored in association with each of the one or more base stations. Then, the control unit selects one of the first communication method and the second communication method based on the information stored in the storage unit. In the first communication method, the control unit causes the terminal station communication unit to perform a reception operation and the base station communication unit to perform a transmission operation during a period in which the base station communication unit performs a reception operation. The transmission operation to the terminal station communication unit is performed within the period. Further, in the second communication method, the control unit causes the terminal station communication unit to perform both the reception operation and the transmission operation during the period in which the base station communication unit is performing the reception operation. That is, in both the first communication method and the second communication method, the reception operation is not performed on the terminal station communication unit within the period in which the communication unit with the base station performs the transmission operation. Therefore, it is possible to avoid a situation in which the transmission radio wave from the base station communication unit becomes an interference wave with respect to the radio wave transmission from the terminal station that the terminal station antenna originally wants to receive. As a result, the communication between the antenna for the base station and the antenna for the terminal station is compared with the case where the communication unit for the terminal station performs the receiving operation during the period during which the communication unit for the base station performs the transmission operation. Since the influence of radio wave interference is reduced, the base station communication unit and the terminal station communication unit do not need to be spaced apart from each other. In addition, since the influence of radio wave interference from the base station communication unit to the terminal station communication unit is small, the minimum reception sensitivity of the terminal station communication unit does not increase, and there is no need to increase the transmission power of the terminal station . As a result, it is possible to reduce the power consumption of the terminal station and to suppress the influence of the transmission radio wave from the terminal station under the wireless relay device on the peripheral base station and the peripheral terminal station.

  Further, in both the first communication method and the second communication method, the terminal station communicates with the terminal station within a period during which the communication unit with the base station performs a transmission operation (that is, a period during which the base station performs a reception operation). On the other hand, the transmission operation is not performed. Therefore, it is possible to avoid a situation in which a transmission radio wave from a terminal station becomes an interference wave with respect to a peripheral base station that is not an original connection destination base station.

Further, in the second communication scheme, it is not necessary to cause the terminal station communication unit to perform the transmission operation within the period in which the base station communication unit is performing the transmission operation. Therefore, it is possible to avoid a situation where the transmission radio wave from the terminal station communication unit becomes an interference wave with respect to the transmission radio wave from the base station communication unit that the base station originally wants to receive. Further, unlike the first communication method, the transmission power of the terminal station communication unit does not need to be equal to the transmission power of the base station communication unit. Therefore, the effect of the transmission radio wave from the terminal station communication unit on the communication performance between the base station communication unit and the base station, the effect of the transmission radio wave from the terminal station communication unit on the surrounding base station, and wireless relay Considering the size of the communicable area required for the device, the transmission power of the terminal station communication unit can be arbitrarily set regardless of the transmission power of the base station communication unit.

  The radio relay apparatus according to a second aspect of the present invention is the radio relay apparatus according to the first aspect, in particular, wherein the control unit is configured such that the second frequency channel is the radio relay among the one or more base stations. The second communication method is selected when interference occurs in a frequency channel used in a peripheral base station that is a base station different from the connection target of the apparatus.

  According to the radio relay apparatus according to the second aspect, the control unit selects the second communication method when the second frequency channel causes interference with the frequency channel used in the neighboring base station. To do. Compared with the first communication method, the second communication method is less affected by communication radio waves in the wireless relay device on the neighboring base stations. Therefore, when the second frequency channel causes interference with the frequency channel used in the neighboring base station, the influence on the neighboring base station can be reduced by selecting the second communication method. . That is, by selecting the second communication method, it is necessary to make the transmission power of the terminal station communication unit equal to the transmission power of the base station communication unit when the first communication method is selected. In addition, because the transmission operation period of the base station communication unit and the transmission operation period of the terminal station communication unit overlap, the transmission radio wave from the terminal station communication unit is transmitted to the base station in the base station. It is possible to avoid a demerit that an interference wave becomes a transmission wave from the communication unit.

  The radio relay apparatus according to a third aspect of the present invention is the radio relay apparatus according to the first aspect, in particular, the control unit is configured such that the second frequency channel is the radio relay among the one or more base stations. The first communication method is selected when interference does not occur in a frequency channel used in a peripheral base station that is a base station different from a device connection target.

  According to the radio relay apparatus according to the third aspect, the control unit uses the first communication method when the second frequency channel does not interfere with the frequency channel used in the neighboring base station. Select. Compared to the second communication method, the first communication method has a greater effect on neighboring base stations, but it is not necessary to reduce the transmission power of the communication unit for the terminal station, so communication between the wireless relay device and the terminal station is possible. The area can be expanded. Therefore, when the second frequency channel does not interfere with the frequency channel used in the neighboring base station, a wide communicable area can be secured by selecting the first communication method. In other words, by selecting the first communication method, the disadvantages of selecting the second communication method (that is, the transmission operation period of the terminal station communication unit is a part of the reception operation period of the base station communication unit) Due to the duplication, it is possible to avoid the demerit that it is necessary to suppress the transmission power of the communication unit with respect to the terminal station.

  The radio relay apparatus according to a fourth aspect of the present invention is the radio relay apparatus according to the first aspect, in particular, the control unit is a base station whose base station antenna is different from a connection target of the radio relay apparatus. When no radio wave is received from a certain peripheral base station, the first communication method is selected.

According to the radio relay apparatus according to the fourth aspect, the control unit selects the first communication method when the antenna for the base station does not receive radio waves from the neighboring base stations. Compared to the second communication method, the first communication method has a greater effect on neighboring base stations, but it is not necessary to reduce the transmission power of the communication unit for the terminal station, so communication between the wireless relay device and the terminal station is possible. The area can be expanded. Therefore, when the antenna for the base station is not receiving radio waves from the neighboring base stations and it is not necessary to consider the influence of the wireless relay device on the neighboring base stations, by selecting the first communication method, A wide communicable area can be secured. In other words, by selecting the first communication method, it is possible to avoid the above disadvantages when the second communication method is selected.

  A frame structure according to a fifth aspect of the present invention is a frame structure of data communicated between a radio relay apparatus and a terminal station, and includes a downlink data burst transmitted from the radio relay apparatus to the terminal station. A downlink subframe in which data including data is stored, and an uplink subframe in which data including an uplink data burst transmitted from the terminal station to the radio relay apparatus is stored, and a subframe length of the downlink subframe, The ratio of the uplink subframe to the subframe length is set within a range defined by a predetermined communication standard, and the downlink subframe is provided with a dedicated pilot zone to which the downlink data burst is not allocated. It is characterized by being.

  According to the frame structure according to the fifth aspect, the ratio between the subframe length of the downlink subframe and the subframe length of the uplink subframe is set within a range defined by a predetermined communication standard such as WiMAX. Yes. Also, a dedicated pilot zone to which no downlink data burst is assigned is provided in the downlink subframe. By providing a dedicated pilot zone to which no downlink data burst is assigned, a non-output transmission operation can be performed from the radio relay apparatus to the terminal station in the zone.

  The frame structure according to the sixth aspect of the present invention is the frame structure according to the fifth aspect, in particular, the head of the downlink subframe transmitted from the radio relay apparatus to the terminal station is the radio relay apparatus from the radio relay apparatus. Out of the downlink subframes transmitted from the radio relay apparatus to the terminal station in synchronization with the beginning of the uplink subframe transmitted to the base station, the downlink subframe transmitted from the base station to the radio relay apparatus The dedicated pilot zone to which the downlink data burst is not allocated is provided in a portion overlapping with a frame.

  According to the frame structure of the sixth aspect, the head of the downlink subframe from the radio relay apparatus to the terminal station is synchronized with the head of the uplink subframe from the radio relay apparatus to the base station, and the radio By providing a dedicated pilot zone to which no downlink data burst is allocated in a portion overlapping with a downlink subframe from the base station to the radio relay device, in the downlink subframe from the relay device to the terminal station, A frame structure for realizing the first communication method can be obtained.

  The frame structure according to the seventh aspect of the present invention is the frame structure according to the fifth aspect, in particular, the head of the uplink subframe transmitted from the terminal station to the radio relay apparatus is the radio from the base station. Of the downlink subframes transmitted from the radio relay apparatus to the terminal station, in synchronization with the head of the downlink subframe transmitted to the relay apparatus, the uplink subframe transmitted from the radio relay apparatus to the base station The dedicated pilot zone to which the downlink data burst is not allocated is provided in a portion overlapping with a frame.

  According to the frame structure according to the seventh aspect, the head of the uplink subframe from the terminal station toward the radio relay apparatus is synchronized with the head of the downlink subframe from the base station to the radio relay apparatus, and the radio By providing a dedicated pilot zone to which no downlink data burst is allocated in a portion overlapping with an uplink subframe from the radio relay apparatus to the base station in the downlink subframe from the relay apparatus to the terminal station, A frame structure for realizing the second communication method can be obtained.

  The frame structure according to an eighth aspect of the present invention is the frame structure according to any one of the fifth to seventh aspects, in particular, the wireless relay device corresponds to a WiMAX communication standard, and the dedicated pilot zone PUSC with dedicated pilot, FUSC with dedicated pilot, O-FUSC with dedicated pilot, AMC 1 × 6 with dedicated pilot, AMC 2 × 3 with dedicated pilot, AMC 3 × 2 with dedicated pilot It is characterized by.

  A control method for a wireless relay device according to a ninth aspect of the present invention includes a pair of antennas for transmitting / receiving radio waves to / from a base station and a pair of terminals for transmitting / receiving radio waves to / from a terminal station. A terminal station antenna, communicating with the base station using a first frequency channel of a plurality of frequency channels, and using a second frequency channel of the plurality of frequency channels A wireless relay apparatus control method for relaying communication between the base station and the terminal station by performing communication with a terminal station, wherein (A) the base station antenna has one or more bases A frequency channel used by each of the one or more radio waves obtained by demodulating one or more radio waves received from a station with a base station communication unit connected to the base station antenna. Information about Storing in association with each of the one or more base stations, and (B) detecting a period during which the communication unit with the base station is performing a transmission operation and a period during which a reception operation is being performed, And a step of controlling a period during which the terminal station communication unit connected to the antenna performs a transmission operation and a period during which a reception operation is performed. In step (B), in step (A) Based on the stored information, the base station communication unit performs a reception operation within a period in which the base station communication unit performs a reception operation, and the base station communication unit performs a transmission operation. A first communication method for causing the terminal-station communication unit to perform a transmission operation within a period during which the communication is performed; and a communication with the terminal station communication within a period during which the base-station communication unit performs a reception operation. Operation and transmission To perform both work, it is characterized in that one is selected with the second communication method.

  According to the control method of the wireless relay device according to the ninth aspect, in step (A), one or more radio waves received by the antenna for the base station from one or more base stations are demodulated and obtained thereby. Information regarding the frequency channel used by each of the one or more radio waves is stored in association with each of the one or more base stations. Further, in step (B), a period during which the base station communication unit is performing a transmission operation and a period during which a reception operation is being performed are detected, and a period during which the terminal station communication unit performs a transmission operation and a reception operation Is controlled. In step (B), one of the first communication method and the second communication method is selected based on the information stored in step (A). In the first communication system, the base station communication unit performs the reception operation and the base station communication unit performs the transmission operation during the period in which the base station communication unit performs the reception operation. A transmission operation is performed to the terminal station communication unit within the period. Further, in the second communication method, both the reception operation and the transmission operation are caused to be performed by the terminal station communication unit within the period during which the terminal base station communication unit is performing the reception operation. That is, in both the first communication method and the second communication method, the reception operation is not performed on the terminal station communication unit within the period in which the communication unit with the base station performs the transmission operation. Therefore, it is possible to avoid a situation in which the transmission radio wave from the base station communication unit becomes an interference wave with respect to the radio wave transmission from the terminal station that the terminal station antenna originally wants to receive. As a result, the communication between the antenna for the base station and the antenna for the terminal station is compared with the case where the communication unit for the terminal station performs the receiving operation during the period during which the communication unit for the base station performs the transmission operation. Since the influence of radio wave interference is reduced, the base station communication unit and the terminal station communication unit do not need to be spaced apart from each other. In addition, since the influence of radio wave interference from the base station communication unit to the terminal station communication unit is small, the minimum reception sensitivity of the terminal station communication unit does not increase, and there is no need to increase the transmission power of the terminal station . As a result, it is possible to reduce the power consumption of the terminal station and to suppress the influence of the transmission radio wave from the terminal station under the wireless relay device on the peripheral base station and the peripheral terminal station.

  Further, in both the first communication method and the second communication method, the terminal station communicates with the terminal station within a period during which the communication unit with the base station performs a transmission operation (that is, a period during which the base station performs a reception operation). On the other hand, the transmission operation is not performed. Therefore, it is possible to avoid a situation in which a transmission radio wave from a terminal station becomes an interference wave with respect to a peripheral base station that is not an original connection destination base station.

  Further, in the second communication scheme, it is not necessary to cause the terminal station communication unit to perform the transmission operation within the period in which the base station communication unit is performing the transmission operation. Therefore, it is possible to avoid a situation where the transmission radio wave from the terminal station communication unit becomes an interference wave with respect to the transmission radio wave from the base station communication unit that the base station originally wants to receive. Further, unlike the first communication method, the transmission power of the terminal station communication unit does not need to be equal to the transmission power of the base station communication unit. Therefore, the effect of the transmission radio wave from the terminal station communication unit on the communication performance between the base station communication unit and the base station, the effect of the transmission radio wave from the terminal station communication unit on the surrounding base station, and wireless relay Considering the size of the communicable area required for the device, the transmission power of the terminal station communication unit can be arbitrarily set regardless of the transmission power of the base station communication unit.

  A radio communication system according to a tenth aspect of the present invention performs communication between a base station and the base station using a first frequency channel among a plurality of frequency channels, and the plurality of frequency channels. A wireless communication system comprising: a wireless relay device that relays communication between the base station and the terminal station by performing communication with the terminal station using the second frequency channel The radio relay device includes: a base station antenna for transmitting / receiving radio waves to / from the base station; a terminal antenna for transmitting / receiving radio waves to / from the terminal station; A base station communication unit connected to a station antenna, a terminal communication unit connected to the terminal antenna, and one or more radio waves received by the base station antenna from one or more base stations. Said base A storage unit that stores information relating to a frequency channel used by each of the one or more radio waves obtained by demodulating in the communication unit in association with each of the one or more base stations; A control unit that detects a period during which the transmission unit performs a transmission operation and a period during which a reception operation is performed, and controls a period during which the terminal station communication unit performs a transmission operation and a period during which the reception operation is performed. And the control unit performs a reception operation with respect to the terminal station communication unit within a period during which the base station communication unit performs a reception operation based on the information stored in the storage unit. And a first communication method for causing the terminal station communication unit to perform a transmission operation within a period during which the base station communication unit performs a transmission operation, and the base station communication unit Within the period of receiving operation To perform both the receiving operation and the transmitting operation to the terminal-station communication unit, and is characterized in that for selecting one of the second communication method.

According to the wireless communication system according to the tenth aspect, the storage unit can be obtained by demodulating one or more radio waves received from the one or more base stations by the anti-base station antenna by the anti-base station communication unit. Information regarding the frequency channel used by each of the one or more radio waves is stored in association with each of the one or more base stations. Then, the control unit selects one of the first communication method and the second communication method based on the information stored in the storage unit. In the first communication method, the control unit causes the terminal station communication unit to perform a reception operation and the base station communication unit to perform a transmission operation during a period in which the base station communication unit performs a reception operation. The transmission operation to the terminal station communication unit is performed within the period. Further, in the second communication method, the control unit causes the terminal station communication unit to perform both the reception operation and the transmission operation during the period in which the base station communication unit is performing the reception operation. That is, in both the first communication method and the second communication method, the reception operation is not performed on the terminal station communication unit within the period in which the communication unit with the base station performs the transmission operation. Therefore, it is possible to avoid a situation in which the transmission radio wave from the base station communication unit becomes an interference wave with respect to the radio wave transmission from the terminal station that the terminal station antenna originally wants to receive. As a result, the communication between the antenna for the base station and the antenna for the terminal station is compared with the case where the communication unit for the terminal station performs the receiving operation during the period during which the communication unit for the base station performs the transmission operation. Since the influence of radio wave interference is reduced, the base station communication unit and the terminal station communication unit do not need to be spaced apart from each other. In addition, since the influence of radio wave interference from the base station communication unit to the terminal station communication unit is small, the minimum reception sensitivity of the terminal station communication unit does not increase, and there is no need to increase the transmission power of the terminal station . As a result, it is possible to reduce the power consumption of the terminal station and to suppress the influence of the transmission radio wave from the terminal station under the wireless relay device on the peripheral base station and the peripheral terminal station.

  Further, in both the first communication method and the second communication method, the terminal station communicates with the terminal station within a period during which the communication unit with the base station performs a transmission operation (that is, a period during which the base station performs a reception operation). On the other hand, the transmission operation is not performed. Therefore, it is possible to avoid a situation in which a transmission radio wave from a terminal station becomes an interference wave with respect to a peripheral base station that is not an original connection destination base station.

  Further, in the second communication scheme, it is not necessary to cause the terminal station communication unit to perform the transmission operation within the period in which the base station communication unit is performing the transmission operation. Therefore, it is possible to avoid a situation where the transmission radio wave from the terminal station communication unit becomes an interference wave with respect to the transmission radio wave from the base station communication unit that the base station originally wants to receive. Further, unlike the first communication method, the transmission power of the terminal station communication unit does not need to be equal to the transmission power of the base station communication unit. Therefore, the effect of the transmission radio wave from the terminal station communication unit on the communication performance between the base station communication unit and the base station, the effect of the transmission radio wave from the terminal station communication unit on the surrounding base station, and wireless relay Considering the size of the communicable area required for the device, the transmission power of the terminal station communication unit can be arbitrarily set regardless of the transmission power of the base station communication unit.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress the subject in a normal rotation system, without arrange | positioning an anti-base station communication part and an anti-terminal station communication part mutually spaced apart.

1 is a diagram schematically showing an overall configuration of a radio communication system according to an embodiment of the present invention. It is a block diagram which shows roughly the internal structure of a radio relay apparatus. It is a timing chart which shows the 1st example about the operation period of transmission / reception. It is a timing chart which shows the 2nd example about the operation period of transmission / reception. It is a timing chart which shows the 3rd example about the operation period of transmission / reception. It is a figure which shows an example of the frame structure in a reverse rotation system. It is a figure which shows an example of the frame structure in a quasi-normal rotation system. It is a flowchart which shows the example of the selection method of the communication system by a control part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the element which attached | subjected the same code | symbol in different drawing shall show the same or corresponding element.

FIG. 1 is a diagram schematically showing an overall configuration of a radio communication system 1 according to an embodiment of the present invention. In a building 2 such as an office or a user's house, a wireless relay device 3 such as an indoor repeater is installed. In the building 2, a terminal station (or mobile station) 4 used by the user is located. The terminal station 4 is a mobile device or a personal computer corresponding to the WiMAX communication standard. In addition, a base station 5 to which the wireless relay device 3 is connected is installed outside the building 2. The terminal station 4 located in the building 2 does not directly receive the transmission radio wave from the base station 5 due to signal attenuation, and communicates with the base station 5 via the wireless relay device 3. . In the example illustrated in FIG. 1, a peripheral base station 9 that is not a connection target of the wireless relay device 3 is installed outside the building 2. The wireless relay device 3 can also receive transmission radio waves from the neighboring base station 9. Here, “receivable” includes not only the case where the received radio wave intensity is equal to or higher than the minimum reception sensitivity, but also the case where it is less than the minimum reception sensitivity.

  The wireless relay device 3 has an external configuration in which a plurality of antennas are attached to one housing. In the example shown in FIG. 1, the wireless relay device 3 transmits and receives radio waves between the antenna 6 </ b> X for transmitting / receiving radio waves to / from the antenna 8 of the base station 5 and the antenna 7 of the terminal station 4. The terminal station antenna 6Y for transmitting and receiving is provided. There may be a plurality of antennas for base station antenna 6X and terminal station antenna 6Y.

  The regenerative type radio relay apparatus 3 once demodulates the radio wave received from the base station 5 received by the antenna 6X for the base station, modulates only the necessary signal, amplifies the signal, and then transmits the terminal from the antenna 6Y for the terminal station. Transmit to station 4. Further, the regenerative type radio relay apparatus 3 once demodulates the radio wave from the terminal station 4 received by the terminal station antenna 6Y, modulates only the necessary signal, amplifies the signal, and then the base station antenna 6X. To the base station 5. In this way, mutual communication between the base station 5 and the terminal station 4 is ensured by passing through the wireless relay device 3. In WiMAX, communication is performed among the wireless relay device 3, the terminal station 4, and the base station 5 using a communication method such as OFDM (Orthogonal Frequency Division Multiplexing) or OFDMA (Orthogonal Frequency Division Multiple Access).

  FIG. 2 is a block diagram schematically showing the internal configuration of the wireless relay device 3. The radio relay device 3 includes a base station communication unit 10 connected to the base station antenna 6X, a terminal station communication unit 20 connected to the terminal antenna 6Y, a control unit 30, and a storage unit 31. It is prepared for. The base station communication unit 10 includes a wireless processing unit 11 and a digital signal processing unit 12. The terminal station communication unit 20 includes a wireless processing unit 21 and a digital signal processing unit 22. In addition, when there are a plurality of antennas 6X and 6Y for terminal stations, there are a plurality of wireless processing units 11 and 12 corresponding to the number.

  The base station communication unit 10 and the terminal station communication unit 20 can each switch and execute a reception operation and a transmission operation. Specifically, the control unit 30 refers to a frame synchronization signal included in the signal received from the base station 5, for example, so that the base station 5 performs a transmission operation (that is, received by the base station communication unit 10). The period during which the operation is performed) and the period during which the base station 5 performs the reception operation (that is, the period during which the base station communication unit 10 performs the transmission operation) are detected. Further, the control unit 30 controls a period during which the terminal station communication unit 20 performs a transmission operation and a period during which a reception operation is performed. The base station communication unit 10 and the terminal station communication unit 20 each switch the reception operation and the transmission operation by a switching operation based on the control signal S7 input from the control unit 30.

  Although not shown, the radio processing unit 11 includes a bandpass filter, a low noise amplifier, a high frequency amplifier, a frequency mixer, an intermediate frequency amplifier, an IQ demodulator, and an AD connected in this order from the base station antenna 6X side. It is configured with a converter. The wireless processing unit 21 includes a DA converter, an IQ modulator, an intermediate frequency amplifier, a frequency mixer, a high frequency amplifier, a power amplifier, and a bandpass filter connected in this order from the digital signal processing unit 22 side. Has been.

When the radio wave received from the base station 5 is relayed and transmitted to the terminal station 4, the radio processing unit 11 amplifies the received radio wave received from the base station antenna 6X, demodulates it, and then AD-converts it. A digital signal S1 is generated. The digital signal processing unit 12 retrieves a necessary signal from the digital signal S1, and reproduces the digital signal S2 by performing predetermined signal processing. The digital signal processing unit 22 generates a transmission signal S3 by performing predetermined signal processing on the digital signal S2. The wireless processing unit 21 transmits the transmission radio wave from the terminal station antenna 6Y by DA-converting the transmission signal S3, modulating the signal, and then amplifying it.

  On the other hand, when the radio wave received from the terminal station 4 is relayed and transmitted to the base station 5, the radio processing unit 21 amplifies the received radio wave received from the terminal station antenna 6Y, demodulates it, and performs AD conversion. Thus, the digital signal S4 is generated. The digital signal processing unit 22 retrieves a necessary signal from the digital signal S4 and performs predetermined signal processing to reproduce the digital signal S5. The digital signal processing unit 12 generates a transmission signal S6 by performing predetermined signal processing on the digital signal S5. The radio processing unit 11 transmits the transmission radio wave from the base station antenna 6X by performing DA conversion on the transmission signal S6, modulating the signal, and then amplifying it.

  FIG. 3 shows a first operation period of transmission / reception of the base station 5, the base station communication unit 10, the terminal station communication unit 20, and the terminal station 4 with respect to one frame which is a data transmission / reception unit of OFDM. It is a timing chart which shows an example. FIG. 3 shows a method in which the base station communication unit 10 and the terminal station communication unit 20 perform reverse transmission / reception operations at all times. This method is referred to as “forward rotation method” in this specification. Called. In the normal rotation system, the base station 5 performs a transmission operation, the base station communication unit 10 performs a reception operation, and the terminal station communication unit 20 performs a transmission operation within a period of time T11 to T12. The terminal station 4 performs a receiving operation. In addition, during the period from time T12 to T13, the base station 5 performs a reception operation, the base station communication unit 10 performs a transmission operation, and the terminal station communication unit 20 performs a reception operation. The terminal station 4 performs a transmission operation.

  As described above, in the normal rotation system, the transmission operation period of the base station communication unit 10 and the reception operation period of the terminal station communication unit 20 are common, and the reception operation period of the base station communication unit 10 The transmission operation period of the terminal station communication unit 20 is common. Therefore, when the transmission radio wave from the base station antenna 6X wraps around the terminal antenna 6Y, the communication performance between the terminal station communication unit 20 and the terminal station 4 is affected, and the terminal station antenna 6Y Sneak around the base station antenna 6X, the communication performance between the base station communication unit 10 and the base station 5 is affected. In determining the communicable area of the wireless relay device 3, the influence of the transmission radio wave from the base station antenna 6X on the communication performance between the terminal station communication unit 20 and the terminal station 4 becomes dominant. In many cases, in order to suppress a decrease in reception sensitivity of the terminal station communication unit 20 due to radio wave interference (in other words, an increase in the minimum reception sensitivity), the reception power of the terminal station communication unit 20 should be increased. It is necessary to increase the transmission power of the terminal station 4. As a result, the power consumption of the terminal station 4 increases, and the possibility that the transmission radio wave from the terminal station 4 under the control of the wireless relay device 3 affects the neighboring base station 9 and the neighboring terminal stations is increased. Further, in order to suppress the influence of the transmission radio wave from the terminal station antenna 6Y on the communication performance between the base station communication unit 10 and the base station 5, from the terminal station antenna 6Y to the base station antenna 6X. It is necessary to reduce the transmission power of the terminal station communication unit 20 in order to suppress the wraparound of the radio waves. This acts in the direction of narrowing the communicable area of the wireless relay device 3. For the reasons described above, the forward rotation method is not a desirable method.

FIG. 4 shows a second example of the transmission / reception operation periods of the base station 5, the base station communication unit 10, the terminal station communication unit 20, and the terminal station 4 with respect to one frame which is a data transmission / reception unit of OFDM. It is a timing chart which shows an example. FIG. 4 shows a method in which the base station communication unit 10 and the terminal station communication unit 20 perform the same transmission / reception operation, and such a method is referred to as a “reversal method” in this specification. In the reverse rotation method, the base station 5 performs a transmission operation, the base station communication unit 10 performs a reception operation, and the terminal station communication unit 20 and the terminal station 4 are within the period of time T21 to T22. Neither transmission nor reception is performed. In addition, time T2
Within the period from 2 to T23, the base station 5 performs a transmission operation, the base station communication unit 10 performs a reception operation, the terminal station communication unit 20 performs a reception operation, and the terminal station 4 Is performing a transmission operation. In addition, during the period from time T23 to T24, the base station 5 performs a reception operation, the base station communication unit 10 performs a transmission operation, and the terminal station communication unit 20 performs a transmission operation. The terminal station 4 performs a receiving operation.

  In the reverse method, the transmission operation period of the base station communication unit 10 and the transmission operation period of the terminal station communication unit 20 are common, and the reception operation period of the base station communication unit 10 and the terminal station communication unit 20 The reception operation period is common. Therefore, the above-described problem of the forward rotation method caused by the wraparound of the radio wave between the base station antenna 6X and the terminal station antenna 6Y does not occur in the reverse rotation method. As a result, compared to the case where the terminal station communication unit 20 performs the reception operation during the period in which the base station communication unit 10 performs the transmission operation (that is, the normal rotation system), Since the influence of mutual interference of communication radio waves with the terminal station antenna 6Y is reduced, it is not necessary to arrange the base station communication unit 10 and the terminal station communication unit 20 apart from each other. That is, since the wireless relay device 3 can be configured by accommodating the base station communication unit 10 and the terminal station communication unit 20 in one housing, the installation work is simplified and the convenience of the user can be improved. Cost can be reduced.

  On the other hand, in the reverse system, the transmission operation period of the base station communication unit 10 and the transmission operation period of the terminal station communication unit 20 are common. Therefore, if the transmission radio field strength from the terminal station antenna 6Y is extremely reduced with respect to the transmission radio field intensity from the base station antenna 6X, the transmission radio wave from the base station antenna 6X in the terminal station 4 becomes an interference wave. Therefore, the reception sensitivity of the terminal station 4 is reduced due to radio wave interference. Therefore, even if the communication area of the wireless relay device 3 is small and sufficient, the transmitted radio wave intensity from the terminal station antenna 6Y needs to be increased more than necessary. The effect on is increased. Further, if the transmission radio wave intensity from the terminal antenna 6Y is extremely increased, the transmission radio wave from the terminal antenna 6Y in the base station 5 becomes an interference wave. Therefore, even if the communication area of the wireless relay device 3 is wide, if the radio wave reception level of the base station antenna 6X from the base station 5 is high, the transmission radio wave intensity from the terminal station antenna 6Y is reduced. Since it is necessary, a situation where the communication area of the wireless relay device 3 cannot be sufficiently covered may occur. As described above, in the reverse rotation method, there is a restriction that the transmission power of the base station communication unit 10 and the transmission power of the terminal station communication unit 20 must be set to the same level. As a result, the influence of the transmission radio wave from the terminal station communication unit 20 on the communication performance between the base station communication unit 10 and the base station 5, and the transmission radio wave from the terminal station communication unit 20 Considering the influence on the base station and the size of the communication area required for the radio relay device 3, the transmission power of the terminal station communication unit 20 is set to a desired value regardless of the transmission power of the base station communication unit 10. There is a demerit that it cannot be set to a value. Further, in the reverse method, the base station 5 and the surrounding base stations are connected to the terminal station because the transmission operation period of the base station communication unit 10 and the transmission operation period of the terminal station communication unit 20 overlap. There is also a demerit that the transmission radio wave from the communication unit 20 becomes an interference wave with respect to the transmission radio wave from the base station communication unit 10. Furthermore, in the reversal method, the terminal station 4 has the transmission operation period of the base station communication unit 10 and the transmission operation period of the terminal station communication unit 20 overlap. There is also a demerit that the transmitted radio wave becomes an interference wave with respect to the transmitted radio wave from the terminal station communication unit 20.

FIG. 5 shows a third example of the transmission / reception operation periods of the base station 5, the base station communication unit 10, the terminal station communication unit 20, and the terminal station 4 with respect to one frame which is a data transmission / reception unit of OFDM. It is a timing chart which shows an example. FIG. 5 shows a scheme in which both the transmission operation period and the reception operation period of the terminal station communication unit 20 correspond to the reception operation period of the base station communication unit 10, and such a method is described in this specification. This is referred to as “quasi-normal rotation system”. In the quasi-normal rotation system, the base station 5 performs a transmission operation, the base station communication unit 10 performs a reception operation, and the terminal station communication unit 20 performs a reception operation within the period of time T31 to T32. And the terminal station 4 is performing a transmission operation. In addition, during the period from time T32 to T33, the base station 5 performs a transmission operation, the base station communication unit 10 performs a reception operation, and the terminal station communication unit 20 performs a transmission operation. The terminal station 4 performs a receiving operation. In addition, during the period from time T33 to T34, the base station 5 performs a receiving operation, the base station communication unit 10 performs a transmission operation, and the terminal station communication unit 20 and the terminal station 4 perform a transmission operation. Neither receive operation.

  By adopting the quasi-normal rotation method, the control unit 30 performs both the reception operation and the transmission operation with respect to the terminal station communication unit 20 within the period during which the communication with the base station communication unit 10 performs the reception operation. Make it. Therefore, it is not necessary for the terminal station communication unit 20 to perform a reception operation within a period during which the terminal station communication unit 10 performs a transmission operation. Therefore, with respect to the transmission radio wave from the terminal station 4 that the terminal station antenna 6Y originally wants to receive, which is the main factor that limits the communicable area of the wireless relay device 3 in the normal rotation system, the base station communication unit 10 It is possible to avoid a situation in which the transmission radio wave from becomes an interference wave. As a result, compared to the case where the terminal station communication unit 20 performs the reception operation during the period in which the base station communication unit 10 performs the transmission operation (that is, the normal rotation system), Since the influence of mutual interference of communication radio waves with the terminal station antenna 6Y is reduced, it is not necessary to arrange the base station communication unit 10 and the terminal station communication unit 20 apart from each other. That is, since the wireless relay device 3 can be configured by accommodating the base station communication unit 10 and the terminal station communication unit 20 in one housing, the installation work is simplified and the convenience of the user can be improved. Cost can be reduced.

  In addition, since the terminal station 4 does not need to perform the transmission operation within the period during which the base station communication unit 10 performs the transmission operation (that is, the period during which the base station 5 performs the reception operation), the original connection destination A situation in which the transmission radio wave from the terminal station 4 becomes an interference wave with respect to the peripheral base station 9 that is not the base station 5 can be avoided.

  Also, unlike the reverse rotation method, the transmission operation period of the base station communication unit 10 and the transmission operation period of the terminal station communication unit 20 do not overlap, so that the transmission radio wave intensity from the terminal station antenna 6Y is increased more than necessary. There is no need. In addition, unlike the reverse method, the reception operation period of the base station 5 and the transmission operation period of the terminal station communication unit 20 do not overlap, so that the transmission radio waves from the terminal station communication unit 20 are transmitted to the base station 5 and the neighboring base stations 9. Can be avoided. As a result, when the communication area to be covered by the wireless relay device 3 is wide, it is possible to set the transmission radio wave intensity from the terminal station antenna 6Y to be large accordingly.

  On the other hand, in the quasi-normal rotation system, the transmission operation period of the terminal station communication unit 20 overlaps with a part of the reception operation period of the base station communication unit 10. Therefore, there is a demerit that it is necessary to suppress the transmission power of the terminal station communication unit 20 in the same way as the normal rotation method in order to suppress the wraparound of the radio wave from the terminal station antenna 6Y to the base station antenna 6X.

  FIG. 6 is a diagram illustrating an example of a frame structure in the reverse rotation method. 6A shows a frame structure of data communicated between the base station 5 and the wireless relay device 3 (corresponding to the uppermost frame structure in FIG. 4). C) shows a frame structure of data communicated between the wireless relay device 3 and the terminal station 4 (corresponding to the third frame structure from the top in FIG. 4). FIG. 6B shows a frame structure at the previous stage of creating the frame structure shown in FIG.

In WiMAX, the ratio between the subframe length of the downlink subframe and the subframe length of the uplink subframe is defined within the range of “35:12” to “26:21”. In FIG. 6A, the subframe length of the downlink subframe (the subframe labeled “Transmission” in the figure, and so on) corresponds to 29 OFDM symbols, and the uplink subframe (in the figure, The subframe length of the subframe labeled “Receive” (the same applies hereinafter) corresponds to 18 symbols.

  In FIG. 6B, the subframe length of the downlink subframe corresponds to 26 symbols of the OFDM symbol, and the subframe length of the uplink subframe corresponds to 21 symbols. In FIG. 6B, the head of the downlink subframe from the radio relay apparatus 3 to the terminal station 4 is the uplink from the radio relay apparatus 3 to the base station 5 in FIG. Synchronized with the beginning of the subframe.

6C, among the downlink subframes from the radio relay apparatus 3 to the terminal station 4 in FIG. 6B, the base station 5 in FIG. 6A to the radio relay apparatus 3 A dedicated pilot zone to which a downlink data burst is not allocated is provided in a portion overlapping the downlink subframe to which it is directed (a portion corresponding to 8 symbols marked with an X in the figure). As a dedicated pilot in WiMAX, PUSC with dedicated
There are pilot, FUSC with dedicated pilot, O-FUSC with dedicated pilot, AMC 1 × 6 with dedicated pilot, AMC 2 × 3 with dedicated pilot, AMC 3 × 2 with dedicated pilot, but any dedicated pilot can be used . By providing a dedicated pilot zone to which no downlink data burst is assigned, a non-output transmission operation can be performed from the radio relay apparatus 3 to the terminal station 4 in the zone.

  FIG. 7 is a diagram illustrating an example of a frame structure in the quasi-normal rotation system. FIG. 7A shows a frame structure of data communicated between the base station 5 and the wireless relay device 3 (corresponding to the uppermost frame structure in FIG. 5). C) shows a frame structure of data communicated between the wireless relay device 3 and the terminal station 4 (corresponding to the third frame structure from the top in FIG. 5). FIG. 7B shows a frame structure at the previous stage of creating the frame structure shown in FIG.

  As in FIG. 6A, in FIG. 7A, the subframe length of the downlink subframe corresponds to 29 symbols of the OFDM symbol, and the subframe length of the uplink subframe corresponds to 18 symbols. To do.

  In FIG. 7B, the subframe length of the downlink subframe corresponds to 35 symbols of the OFDM symbol, and the subframe length of the uplink subframe corresponds to 12 symbols. 7B, the head of the uplink subframe from the terminal station 4 toward the radio relay apparatus 3 is the downlink from the base station 5 to the radio relay apparatus 3 in FIG. Synchronized with the beginning of the subframe.

  7C, among the downlink subframes from the radio relay apparatus 3 to the terminal station 4 in FIG. 7B, the radio relay apparatus 3 to the base station 5 in FIG. A dedicated pilot zone to which a downlink data burst is not allocated is provided in a portion overlapping the uplink subframe toward (a portion corresponding to 18 symbols marked with an X in the figure). As above, dedicated pilots in WiMAX include PUSC with dedicated pilot, FUSC with dedicated pilot, O-FUSC with dedicated pilot, AMC 1 × 6 with dedicated pilot, AMC 2 × 3 with dedicated pilot, AMC There are 3x2 with dedicated pilots, but any dedicated pilot may be used. By providing a dedicated pilot zone to which no downlink data burst is assigned, a non-output transmission operation can be performed from the radio relay apparatus 3 to the terminal station 4 in the zone.

As described above, the reverse rotation method and the quasi-forward rotation method have advantages and disadvantages, respectively. Therefore, in the wireless relay device 3 according to the present embodiment, the reverse rotation method and the quasi-normal rotation method are switched and selected according to the situation.

  The wireless relay device 3 is assigned a frequency band that can be used for communication with the base station 5 and the terminal station 4, and there are a plurality of frequency bands (N in the following example, N is an integer of 2 or more). It is divided into frequency channels F1, F2, F3,. In the following example, it is assumed that the frequency gradually increases in the order of frequency channels F1, F2, F3,. In this case, the frequency channel F1 is the lowest frequency and the frequency channel FN is the highest frequency. In this embodiment, as an example, N = 3, and the radio relay apparatus 3 uses the frequency channel F1 for communication with the terminal station 4 and uses the frequency channel F2 or F3 for communication with the base station 5. Shall. The peripheral base station 9 also uses the frequency channel F2 or F3.

  Referring to FIG. 2, the base station communication unit 10 demodulates one or more radio waves received by the base station antenna 6X from one or more base stations (including the base station 5 and the peripheral base station 9). Thus, one or more frequency channels used by the one or more radio waves are specified from among the frequency channels F2 and F3. Information relating to the identified frequency channel is stored in the storage unit 31 in association with each of the one or more base stations. That is, the correspondence between the identification information of the base station and the frequency channel used by each base station is stored in the storage unit 31. Here, “the radio relay device is receiving radio waves from the base station” means that the radio relay device and the base station are synchronized, and the radio relay device receives a control signal from the base station. In addition, this means a situation where RSSI (Received Signal Strength Indication) can be measured in the wireless relay device. As an index representing communication quality, CINR (Carrier to Interference-plus-Noise Ratio) may be used instead of RSSI (the same applies hereinafter). The control unit 30 reads information on the frequency channel received from the base station from the storage unit 31 as reception signal information S8. For example, when the wireless relay device 3 receives the frequency channel F2 from the base station 5 and receives the frequency channel F3 from the neighboring base station 9, the received signal information S8 indicating the frequency channels F2 and F3 is: Input from the storage unit 31 to the control unit 30. The base station communication unit 10 measures RSSI (or CINR) of the received signals from the one or more base stations, and provides information on the measured RSSI (or CINR) of the one or more base stations. The information is stored in the storage unit 31 in association with each other. Information regarding RSSI (or CINR) is read from the storage unit 31 by the control unit 30 by being included in the received signal information S8.

  The control unit 30 selects the reverse rotation method or the quasi-forward rotation method as the communication method employed by the wireless relay device 3 based on the received signal information S8. FIG. 8 is a flowchart illustrating an example of a communication method selection method by the control unit 30. First, in step SP11, the control unit 30 determines based on the received signal information S8 whether or not a radio wave is received from the neighboring base station 9 in addition to the base station 5 to be connected.

  When the wireless relay device 3 does not receive radio waves from the neighboring base station 9 (that is, when the determination result in step SP11 is “NO”), the control unit 30 selects the reverse rotation method. Compared with the quasi-forward rotation method, the reverse rotation method has a larger influence on the neighboring base stations 9, but it is not necessary to suppress the transmission power of the terminal station communication unit 20, so that the wireless relay device 3 and the terminal station 4 can communicate with each other. The area can be expanded. Therefore, when the antenna for the base station 6X is not receiving radio waves from the neighboring base station 9 and it is not necessary to consider the influence of the wireless relay device 3 on the neighboring base station 9, the reverse rotation method is selected. A wide communicable area can be secured. That is, by selecting the reverse rotation method, the demerit when the quasi-forward rotation method is selected (that is, the transmission operation period of the terminal station communication unit 20 overlaps with a part of the reception operation period of the base station communication unit 10). For this reason, it is possible to avoid the demerit that it is necessary to suppress the transmission power of the terminal station communication unit 20.

  On the other hand, if the wireless relay device 3 is receiving radio waves from the neighboring base station 9 (that is, if the determination result in step SP11 is “YES”), then in step SP12, the control unit 30 causes the wireless relay device 3 to Determines whether the radio wave received from the neighboring base station 9 is only the frequency channel F3 (in other words, does not include the frequency channel F2) based on the received signal information S8. That is, whether or not the frequency channel used by the wireless relay device 3 for communication with the terminal station 4 and the frequency channel received by the wireless relay device 3 from the neighboring base station 9 cause interference with each other. judge. In the example of the present embodiment, the peripheral base station 9 can use two frequency channels F2 and F3, but the peripheral base station 9 may use three or more frequency channels. In this case, depending on whether the frequency channel used by the wireless relay device 3 for communication with the terminal station 4 and the frequency channel received by the wireless relay device 3 from the neighboring base station 9 are adjacent to each other, It may be determined whether or not interference occurs.

  When the radio wave received from the peripheral base station 9 is only the frequency channel F3 (that is, when the determination result in step SP12 is “YES”), the control unit 30 selects the reverse rotation method. Since the frequency channel F1 and the frequency channel F3 are not adjacent to each other, the frequency channel F1 and the frequency channel F3 are small enough not to cause radio wave interference or affect communication performance. Therefore, in this case, a wide communicable area can be secured by selecting the reverse rotation method. That is, by selecting the reverse rotation method, it is possible to avoid the above disadvantages when the quasi-normal rotation method is selected.

  On the other hand, when the radio wave received from the peripheral base station 9 is the frequency channel F2 (that is, when the determination result in step SP12 is “NO”), the control unit 30 selects the quasi-normal rotation method. Even when the wireless relay device 3 receives the frequency channels F2 and F3 from a plurality of neighboring base stations, the control unit 30 adopts the quasi-normal rotation method. Compared with the reverse rotation method, the quasi-forward rotation method has less influence on the neighboring base station 9 by the communication radio wave in the wireless relay device 3. Therefore, when the frequency channel F2 adjacent to the frequency channel F1 is used in the peripheral base station 9, the influence on the peripheral base station 9 can be reduced by selecting the quasi-normal rotation method. That is, by selecting the quasi-normal rotation method, it is necessary to make the transmission power of the terminal station communication unit 20 equal to the transmission power of the base station communication unit 10 when the reverse method is selected (i.e., In addition, the base station 5 and the neighboring base stations 9 have the transmission operation period of the base station communication unit 10 and the transmission operation period of the terminal station communication unit 20 overlapped. Can be avoided as a transmission wave from the base station communication unit 10 becomes an interference wave.

As described above, according to the wireless relay device 3 according to the present embodiment, the storage unit 31 receives one or more radio waves received by the base station antenna 6X from one or more base stations. The information about the frequency channel used by each of the one or more radio waves obtained by demodulating in (1) is stored in association with each of the one or more base stations. Then, the control unit 30 selects one of the reverse rotation method and the quasi-normal rotation method based on the information stored in the storage unit 31. In the reversing method, the control unit 30 causes the terminal station communication unit 20 to perform a reception operation during the period in which the base station communication unit 10 performs a reception operation, and the base station communication unit 10 performs a transmission operation. The terminal station communication unit 20 is caused to perform a transmission operation within the period of time. Further, in the quasi-normal rotation system, the control unit 30 causes the terminal station communication unit 20 to perform both the reception operation and the transmission operation within the period during which the terminal base station communication unit 10 performs the reception operation. That is, in any of the reverse rotation method and the quasi-forward rotation method, the reception operation is not performed for the terminal station communication unit 20 within the period during which the communication with the base station communication unit 10 performs the transmission operation. Therefore, it is possible to avoid a situation where the transmission radio wave from the base station communication unit 10 becomes an interference wave with respect to the transmission radio wave from the terminal station 4 that the terminal station antenna 6Y originally wants to receive. As a result, as compared with the case where the terminal station communication unit 20 performs the reception operation during the period in which the base station communication unit 10 performs the transmission operation (forward rotation method), Since the influence of mutual interference of communication radio waves with the terminal station antenna 6Y is reduced, it is not necessary to arrange the base station communication unit 10 and the terminal station communication unit 20 apart from each other. Further, since the influence of radio wave interference from the base station communication unit 10 to the terminal station communication unit 20 is small, the minimum reception sensitivity of the terminal station communication unit 20 does not increase, and the transmission power of the terminal station 4 is reduced. There is no need to raise it. As a result, the power consumption of the terminal station 4 can be reduced, and the influence of the transmission radio wave from the terminal station 4 under the wireless relay device 3 on the peripheral base station 9 and the peripheral terminal station can be suppressed.

  Further, in both the reverse rotation method and the quasi-forward rotation method, the terminal station 4 can be connected to the terminal station 4 within a period during which the communication unit 10 performs a transmission operation (that is, a period during which the base station 5 performs a reception operation). To prevent transmission. Therefore, it is possible to avoid a situation in which the transmission radio wave from the terminal station 4 becomes an interference wave with respect to the peripheral base station 9 which is not the base station 5 to which the original connection is made.

  Further, in the quasi-normal rotation system, it is not necessary to cause the terminal station communication unit 20 to perform a transmission operation within a period during which the terminal base station communication unit 10 performs a transmission operation. Therefore, it is possible to avoid a situation in which the transmission radio wave from the terminal station communication unit 20 becomes an interference wave with respect to the transmission radio wave from the base station communication unit 10 that the base station 5 originally wants to receive. Unlike the reverse rotation method, the transmission power of the terminal station communication unit 20 does not need to be equal to the transmission power of the base station communication unit 10. Therefore, the influence of the transmission radio wave from the terminal station communication unit 20 on the communication performance between the base station communication unit 10 and the base station 5 and the transmission radio wave from the terminal station communication unit 20 affect the surrounding base station 9. The transmission power of the terminal station communication unit 20 is arbitrarily set regardless of the transmission power of the base station communication unit 10 in consideration of the influence and the size of the communicable area required for the wireless relay device 3. Is possible.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of claims for patent, and is intended to include all modifications within the scope and meaning equivalent to the scope of claims for patent.

DESCRIPTION OF SYMBOLS 1 Wireless communication system 3 Wireless relay apparatus 4 Terminal station 5 Base station 6X vs. base station antenna 6Y vs. terminal station antenna 10 vs. base station communication part 20 vs. terminal station communication part 30 Control part 31 Storage part

Claims (10)

Communication is performed with a base station using a first frequency channel among a plurality of frequency channels, and communication is performed with a terminal station using a second frequency channel among the plurality of frequency channels. A wireless relay device that relays communication between the base station and the terminal station,
An antenna for a base station for transmitting and receiving radio waves to and from the base station;
A terminal station antenna for transmitting and receiving radio waves to and from the terminal station;
A base station communication unit connected to the base station antenna;
A terminal-station communication unit connected to the terminal-station antenna;
The frequency channel used by each of the one or more radio waves obtained by demodulating one or more radio waves received by the antenna for the base station from one or more base stations by the communication unit for the base station A storage unit for storing information in association with each of the one or more base stations;
A period during which the base station communication unit performs a transmission operation and a period during which a reception operation is performed are detected, and a period during which the terminal station communication unit performs a transmission operation and a period during which a reception operation is performed. A control unit for controlling,
The control unit is based on the information stored in the storage unit,
The terminal communication unit is allowed to perform a reception operation within a period during which the base station communication unit is performing a reception operation, and the base station communication unit is within a period during which the base station communication unit is performing a transmission operation. A first communication method for causing the terminal station communication unit to perform a transmission operation;
A radio that selects one of the second communication schemes that allows the terminal station communication unit to perform both the reception operation and the transmission operation within a period during which the base station communication unit performs the reception operation. Relay device.   The control unit interferes with a frequency channel used in a peripheral base station that is a base station that is different from a connection target of the wireless relay device among the one or more base stations. The radio relay apparatus according to claim 1, wherein when it occurs, the second communication method is selected.   The control unit interferes with a frequency channel used in a peripheral base station that is a base station that is different from a connection target of the wireless relay device among the one or more base stations. The wireless relay device according to claim 1, wherein the first communication method is selected if it does not occur.   The control unit selects the first communication method when the antenna for the base station does not receive a radio wave from a neighboring base station that is a base station different from a connection target of the wireless relay device. Item 4. The wireless relay device according to Item 1. A frame structure of data communicated between a radio relay apparatus and a terminal station,
A downlink subframe in which data including a downlink data burst transmitted from the radio relay apparatus to the terminal station is stored;
An uplink subframe in which data including an uplink data burst transmitted from the terminal station to the wireless relay device is stored;
The ratio of the subframe length of the downlink subframe and the subframe length of the uplink subframe is set within a range defined by a predetermined communication standard,
A frame structure in which the downlink subframe is provided with a dedicated pilot zone to which the downlink data burst is not allocated. The head of the downlink subframe transmitted from the radio relay apparatus to the terminal station is synchronized with the head of the uplink subframe transmitted from the radio relay apparatus to the base station,
Of the downlink subframe transmitted from the radio relay apparatus to the terminal station, the downlink data burst is not allocated to a portion overlapping with the downlink subframe transmitted from the base station to the radio relay apparatus. 6. A frame structure according to claim 5, wherein a dedicated pilot zone is provided. The head of the uplink subframe transmitted from the terminal station to the radio relay apparatus is synchronized with the head of the downlink subframe transmitted from the base station to the radio relay apparatus,
Of the downlink subframe transmitted from the radio relay apparatus to the terminal station, the downlink data burst is not allocated to a portion overlapping with an uplink subframe transmitted from the radio relay apparatus to the base station. 6. A frame structure according to claim 5, wherein a dedicated pilot zone is provided. The wireless relay device supports the WiMAX communication standard,
In the dedicated pilot zone, one of PUSC with dedicated pilot, FUSC with dedicated pilot, O-FUSC with dedicated pilot, AMC 1 × 6 with dedicated pilot, AMC 2 × 3 with dedicated pilot, AMC 3 × 2 with dedicated pilot The frame structure according to claim 5, wherein: is used. A base station antenna for transmitting and receiving radio waves to and from the base station; and a terminal antenna for transmitting and receiving radio waves to and from the terminal station, the first of the plurality of frequency channels By communicating with the base station using a frequency channel, and communicating with the terminal station using a second frequency channel of the plurality of frequency channels, A method of controlling a wireless relay device that relays communication with the terminal station,
(A) One or more radio waves received by the base station antenna from one or more base stations are demodulated by a base station communication unit connected to the base station antenna, and obtained thereby, Storing information relating to frequency channels used by each of the one or more radio waves in association with each of the one or more base stations;
(B) Detecting a period during which the base station communication unit performs a transmission operation and a period during which a reception operation is performed, and performs a transmission operation with respect to the terminal station communication unit connected to the terminal antenna And a step of controlling a period for performing and a period for performing the receiving operation,
In the step (B), based on the information stored in the step (A),
The terminal station communication unit performs a reception operation within a period during which the base station communication unit performs a reception operation, and the base station communication unit performs a transmission operation during the period during which the base station communication unit performs a transmission operation. A first communication method for causing the terminal station communication unit to perform a transmission operation;
One of the second communication methods is selected, which allows the terminal station communication unit to perform both the reception operation and the transmission operation within the period in which the base station communication unit is performing the reception operation. A method for controlling a wireless relay device. A base station,
Communicating with the base station using a first frequency channel among a plurality of frequency channels, and communicating with a terminal station using a second frequency channel among the plurality of frequency channels A wireless communication system comprising a wireless relay device that relays communication between the base station and the terminal station by performing
The wireless relay device is
An antenna for a base station for transmitting and receiving radio waves to and from the base station;
A terminal station antenna for transmitting and receiving radio waves to and from the terminal station;
A base station communication unit connected to the base station antenna;
A terminal-station communication unit connected to the terminal-station antenna;
The frequency channel used by each of the one or more radio waves obtained by demodulating one or more radio waves received by the base station antenna from one or more base stations by the communication unit for the base station A storage unit for storing information in association with each of the one or more base stations;
A period during which the base station communication unit performs a transmission operation and a period during which a reception operation is performed are detected, and a period during which the terminal station communication unit performs a transmission operation and a period during which a reception operation is performed. A control unit for controlling,
The control unit is based on the information stored in the storage unit,
The terminal communication unit is allowed to perform a reception operation within a period during which the base station communication unit is performing a reception operation, and the base station communication unit is within a period during which the base station communication unit is performing a transmission operation. A first communication method for causing the terminal station communication unit to perform a transmission operation;
A radio that selects one of the second communication schemes that allows the terminal station communication unit to perform both the reception operation and the transmission operation within a period during which the base station communication unit performs the reception operation. Communications system.

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