JP5561321B2 - Wireless communication device - Google Patents

Description

  The present invention relates to a wireless communication apparatus.

  In cellular radio, when a base station is installed in an area covered by a radio communication service, the arrangement of each base station is designed so that a radio terminal can perform radio communication with at least one base station. An area covered by one base station is called a “cell”. However, even when a plurality of base stations are installed, there may be dead spots where the wireless terminal cannot perform wireless communication with any base station due to terrain restrictions or shielding by buildings.

  In general, after the power is turned on, the wireless terminal scans a preset frequency to detect whether there is a connectable base station, and if detected, connects to the base station. A connection request is issued to the base station to try. On the other hand, when the wireless terminal cannot detect the presence of the base station, the wireless terminal is not allowed to transmit the radio wave for reasons such as the presence or absence of permission to use the radio wave. In addition, even if the wireless terminal can receive radio waves from the base station, if the base station cannot recognize the connection request radio waves issued from the wireless terminal, communication between the wireless terminal and the base station is still possible. Cannot be established.

  Therefore, in order to eliminate such inconvenience and establish communication between the wireless terminal and the base station, a relay station is installed. The relay station relays radio waves from the base station to the radio terminal, while relaying radio waves from the radio terminal to the base station. When a relay station is used in this way, the wireless terminal responds to the radio wave from the relay station instead of directly responding to the radio wave from the base station, resulting in communication between the base station and the wireless terminal. Can be established. Alternatively, the relay station relays radio waves emitted from the radio terminal to the base station, and the base station recognizes radio waves from the radio terminal via the relayed radio waves and establishes subsequent communication. it can.

  Here, the specifications of the radio relay station are being studied by the IEEE 802.16 working group under the IEEE of the American Society. According to the draft specifications, the relay station in the transparent mode and the relay station in the non-transparent mode are defined. (See Non-Patent Document 1). In the transparent mode, the wireless terminal receives broadcast information transmitted from the base station, and the relay station relays only data communication. On the other hand, in the non-transparent mode, the relay station operates to be equivalent to the base station for the wireless terminal. Therefore, the broadcast information that is normally transmitted by the base station must be constantly transmitted in the same manner as the base station.

  In addition, in multi-hop connection between a wireless terminal and a base station, a technology that makes it possible to recognize the presence of a relay device for connection to a base station without increasing power consumption has been disclosed (for example, Patent Documents). 1). In this technique, a relay device that performs relay attempts to suppress power consumption by performing a predetermined reception operation for the same time as the reception slot of a control signal from a base station.

JP 2006-254155 A

IEEE draft standard P802.16j / D3

  In wireless communication between a wireless terminal and a base station, when broadcast information from the base station reaches the wireless terminal, the wireless terminal issues a connection request to the base station. However, if this transmitted connection request does not reach the base station, the base station cannot recognize the wireless terminal, which means that the base station does not recognize the existence of the wireless terminal to be relayed. The station cannot be a trigger for instructing the relay station to perform a relay operation.

  Therefore, in order to ensure that the connection request issued from the wireless terminal is delivered to the base station, the relay station always consumes power for the relay operation if the relay station is set to a state where the relay operation can always be performed. Will do. This leads to a waste of power in situations where it is not known when a connection request comes from a wireless terminal. Moreover, since the relay station always transmits broadcast information transmitted from the base station by being always started up so that the relay station can perform a relay operation, there is also a target wireless terminal. Under such circumstances, radio resources are wasted, and in some cases, it may interfere with surrounding communications and contribute to performance degradation of the entire wireless communication system.

  In view of the above-described problems, the present case avoids, as much as possible, suppression of power consumption and waste of radio wave resources in the relay station when performing relay operation by the relay station in wireless communication between the wireless terminal and the base station. The purpose is to do.

  In order to solve the above-described problem, a wireless communication apparatus capable of communicating with a wireless terminal includes a receiving unit that receives a connection request transmitted from the wireless terminal to a base station, and the reception of the connection request as a trigger. Means for performing control to switch between an operation state in which a communication operation equivalent to a base station is performed with a wireless terminal and a standby state in which the communication operation is not performed.

  When a relay operation is performed by a relay station in wireless communication between a wireless terminal and a base station, power consumption at the relay station and waste of radio wave resources are avoided as much as possible.

It is a figure which shows schematic structure of a radio | wireless communications system. It is a functional block diagram of this relay station according to the function exhibited in the relay station included in the communication system shown in FIG. It is a 1st flowchart for the starting process of this relay station performed in a relay station. It is a figure which shows the 1st notification aspect in the random access channel at the time of notifying the connection request issued from the radio | wireless terminal to a base station from a relay station. It is a figure which shows the 2nd notification aspect in the random access channel at the time of notifying the connection request issued from the radio | wireless terminal to a base station from a relay station. It is a 2nd flowchart for the starting process of this relay station performed in a relay station. It is a 3rd flowchart for the starting process of this relay station performed in a relay station. FIG. 10 is a fourth flowchart for starting processing of the relay station, executed in the relay station. It is a figure which shows schematic structure of the radio | wireless frame regarding a base station and a relay station. It is a functional block diagram of a relay station.

  Here, an embodiment of the above-described relay station and a wireless communication system including the relay station will be described based on the following drawings. The configuration of the embodiment described below is an example of a range that satisfies the requirements required by the Patent Law, and the scope of rights of the present invention is not limited to the configuration of the following embodiment.

  FIG. 1 shows a state in which the two wireless communication systems 1 in this case are connected via a network. Since the configurations of the respective wireless communication systems are basically the same, one wireless communication system 1 will be described in detail when there is no need to describe them individually. The wireless communication system 1 is provided with one base station 2. The base station 2 is connected in a communicable state with the base station 2 in another wireless communication system via a network. As a result, wireless terminals (indicated by reference numerals 4 and 5 in FIG. 1) existing in the communicable area (hereinafter also referred to as “cell”) of the base station 2 are placed in the communicable area of the same base station 2. Wireless communication can be performed with an existing wireless terminal or a wireless terminal existing in a communicable area of another base station 2.

  Further, the radio communication system 1 is provided with a relay station 3 in addition to the base station 2. The relay station 3 performs a relay operation of relaying the radio wave from the base station 2 to the radio terminal in the cell while relaying the radio wave from the radio terminal in the cell to the base station. Through this relay operation, communication can be established between the base station and the wireless terminal, and the cell of the wireless communication system 1 can be expanded.

  Next, a general sequence for establishing an initial connection for wireless communication between the base station 2 and the wireless terminals 4 and 5 in the wireless communication system 1 will be described. First, the base station 2 uses a random access channel for transmitting a connection request to the base station 2 later by a wireless terminal (for example, a terminal immediately after being turned on) whose communication is not established with a certain synchronization signal. Information about Hereinafter, this information is referred to as notification information. Then, the wireless terminal issues a connection request to the base station 2 through the random access channel in a form corresponding to the broadcast information, so that the base station 2 recognizes the presence of the wireless terminal, and thereafter between the two Communication will be established.

  Here, the radio communication system 1 can roughly divide the cell into two regions R1 and R2. The area R1 is an area in which notification information from the base station 2 is delivered to the wireless terminal 4 existing in the area R1, but a connection request signal from the wireless terminal 4 does not reach the base station 2 directly. . Therefore, when a connection request is issued from the wireless terminal 4, a relay operation by the relay station 3 is performed, so that communication between the wireless terminal 4 and the base station 2 is established. On the other hand, the region R2 is a region where the broadcast information from the base station 2 is delivered to the wireless terminal 5 existing in the region R2, and the connection request signal from the wireless terminal 4 is also delivered directly to the base station 2. . Therefore, when a connection request is issued from the wireless terminal 5, the relay operation by the relay station 3 is not performed, and communication between the wireless terminal 5 and the base station 2 is established.

  Thus, the receivable area (R1) by the wireless terminal in the direction from the base station 2 toward the wireless terminals 4 and 5 (hereinafter also referred to as “downward direction”) is the direction from each wireless terminal toward the base station 2 ( (Hereinafter, also referred to as “uplink direction”), an area in which broadcast information necessary for initial synchronization of the wireless terminal reaches the wireless terminal by being set wider than the transmittable area (R2) of the wireless terminal to the base station 2 And the area where the corresponding connection request is delivered to the base station is an unbalanced state (the state shown in FIG. 1). However, as described above, since the wireless communication system 1 includes the relay station 3, by using the relay operation by the relay station 3, the wireless terminal (for example, the wireless terminal 4) existing in the region R1 is eventually used. Thus, communication with the base station 2 can be established. That is, the unbalanced state of the areas R1 and R2 contributes to expanding the cell area of the radio communication system 1 based on the base station 2.

  Thus, in order to form the unbalanced state of the regions R1 and R2, the following methods (1) to (5) can be employed. Since each of these methods is based on conventional techniques, a detailed description thereof will be omitted.

  (1) The transmission level of the initial synchronization signal in the downstream direction is set higher than the transmission level of the initial synchronization signal in the upstream direction.

  (2) The modulation method of the initial synchronization signal in the downlink direction is set lower than the modulation method of the initial synchronization signal in the uplink direction.

  (3) The coding rate of the initial synchronization signal in the downlink direction is set lower than the coding rate of the initial synchronization signal in the uplink direction.

  (4) When performing spread spectrum communication in wireless communication with the base station 2, the spreading factor of the initial synchronization signal in the downlink direction is set higher than the spreading factor of the initial synchronization signal in the uplink direction.

(5) The initial synchronization signal in the downlink direction is transmitted by repeated code transmission.
Each of these methods may be used, or a plurality of methods may be used in combination.

  In the relay station 3, the relay operation is performed intermittently. That is, the relay station 3 does not always perform a relay operation, but performs a relay operation when it is necessary to perform a relay operation in response to a connection request from the wireless terminals 4 and 5. By doing so, it becomes possible to suppress power consumption and waste of frequency resources caused by the activation of the relay station 3. Therefore, in the series of processing executed for starting up the relay station 3, each function exhibited in the relay station 3 is imaged as a functional unit in FIG. The functions of these functional units are exhibited mainly when a predetermined control program is executed by the control device in the relay station 2. Below, it demonstrates centering on the correlation of each function part.

  First, the relay standby unit 31 stops processing related to the relay operation other than reception of connection requests from the wireless terminals including the wireless terminals 4 and 5, and puts the relay station 3 in the relay standby state. Therefore, the relay station 3 set in the relay standby state by the relay standby unit 31 does not consume power other than receiving a connection request from the wireless terminals 4, 5, and the like. Here, in order to receive the connection request from the wireless terminals 4, 5, etc., reception of the random access channel used for sending the connection request of each wireless terminal based on the broadcast information transmitted from the base station 2. Operation will be performed. Then, the connection request detecting unit 32 receives a wireless terminal corresponding to the broadcast information from the base station 2 through the reception operation of the random access channel by the relay standby unit 31 (in this embodiment, the wireless terminals 4 and 5). Detect connection request from.

  Next, the response determination unit 33 determines whether or not the base station 2 has responded to each wireless terminal that has issued the connection request. Further, the prediction unit 34 predicts the signal strength and signal quality of the connection request from each wireless terminal for determining whether the relay operation can be stably performed by the relay station 3. The base station communication establishment unit 35 establishes communication when the communication between the base station 2 and the relay station 3 is not established, and maintains the communication when established. The relay operation unit 36 notifies the base station 2 of the received connection request from the wireless terminal based on the processing results of the respective functional units, and then moves from the relay standby state to the relay operation state to change between the wireless terminal and the base station Relay communication with 2.

Here, the starting process for starting the relay station 3 having the above-described functional units from the state where the relay operation is stopped will be described with reference to FIGS. For example, the relay station activation process is performed in response to the wireless terminal 4 that cannot directly send a connection request to the base station 2. First, in S101, it is determined whether or not the relay standby unit 31 has received a connection request from the wireless terminal 4. If a negative determination is made here, the standby state of the relay operation of the relay station 3 is maintained by the relay standby unit 31 in S102 as well. If an affirmative determination is made in S101, the process proceeds to S103, and the connection request detection unit 32 detects a connection request from the wireless terminal 4.

  Then, when the connection request from the wireless terminal 4 is detected in S103, activation of the relay station 3 is started after S104. First, in S104, a connection request to the base station 2 of the relay station 3 itself is transmitted to the base station 2 using a random access channel. That is, since it is not necessary to connect the relay station 3 to the base station 2 when the relay station 3 is not activated, the relay station 3 and the relay station 3 are activated together with the activation of the relay station 3 for the wireless terminal 4. Communication with the base station 2 is to be established again. Then, after the processing of S104, communication is established between the relay station 3 and the base station 2 after waiting for a response from the base station 2 (processing of S105). The processes of S104 and S105 are performed by the base station communication establishment unit 35. If communication has already been established between the relay station 3 and the base station 2, the processes of S104 and S105 do not need to be performed.

  When communication is established between the relay station 3 and the base station 2, a connection request issued from the wireless terminal 4 is notified to the base station 2 by the relay operation unit 36 using the communication (processing of S106). ). In this way, the relay station 3 notifies the connection request issued from the wireless terminal 4 to the base station 2 on behalf of the wireless terminal 4, and as a result, communication between the wireless terminal 4 and the base station 2 is performed. It is possible to establish a transition from the relay standby state to the relay operation state. At this time, the activation of the relay station 3 is triggered by the detection of the connection request by the connection request detection unit 32, so that the activation of the relay station 3 is adjusted. It is possible to suppress the frequency resources used from being unnecessarily expanded.

  Here, as another form of the method for notifying the base station 2 of the connection request for the transition from the relay standby state to the relay operation state by the relay operation unit 36, the method shown in FIG. 4A or 4B can be adopted. is there. For example, in the method shown in FIG. 4A, the connection request is transmitted on the random access channel used by the wireless terminal 4 in the upstream direction toward the base station 2. At this time, the connection request signal is amplified on the relay station 3 side. 4B, the connection request may be transmitted to the base station 2 using a notification-dedicated area that is different from the terminal transmission area of the random access channel used by the wireless terminal 4. In this case, the base station 2 can recognize that the transmitted connection request is not directly delivered from the wireless terminal 4 but is relayed by the relay station 3.

  Next, a second embodiment of the activation process of the relay station 2 will be described with reference to FIG. 5 that are the same as those in the control flow shown in FIG. 3 are assigned the same reference numerals, and detailed descriptions thereof are omitted. In the relay station activation process according to the present embodiment, when the process of S103 ends, the determination process of S201 is performed. In S201, the response determination unit 33 determines whether there is a response from the base station 2 in response to the connection request issued from the wireless terminal. Since the sequence of the base station 2 after a connection request is made from each wireless terminal using a random access channel is generally determined, the response determination unit 33 monitors this sequence to detect the connection detected in S103. It can be determined whether or not the base station 2 responds to the wireless terminal that issued the request.

With respect to the wireless terminals 4 and 5 existing at the position shown in FIG. 1, since the wireless terminal 5 exists in the region R2 and the base station 2 can recognize the connection request issued by itself, the base station 2 2 to respond to the connection request. Therefore, the response determination unit 33 monitors this process, whereby the wireless terminal 5 is determined to have a response from the base station 2, that is, an affirmative determination is made. On the other hand, since the wireless terminal 4 does not exist in the region R2 and the base station 2 cannot recognize the connection request issued by itself, processing for responding to the connection request from the base station 2 is performed. Absent. Therefore, the response determination unit 33 monitors this process. For example, when there is no process from the base station 2 after the elapse of a certain time from the connection request detection in S103, the response from the base station 2 is received for the wireless terminal 4. It is determined that there is no error, that is, a negative determination is made.

  Thus, if an affirmative determination is made in S201, direct wireless communication is possible between the wireless terminal 5 and the base station 2, so that it is not necessary to start the relay station 3. Therefore, in this case, the relay station activation process is terminated. Further, if a negative determination is made in S201, direct wireless communication cannot be performed between the wireless terminal 5 and the base station 2, and thus the activation of the relay station 3 is started by the processing after S104. As described above, the activation of the relay station 3 is adjusted more accurately, and thus it is possible to suppress the power consumed in the relay station 3 and the frequency resources used from being unnecessarily expanded.

  Next, a third embodiment of the activation process of the relay station 2 will be described with reference to FIG. In addition, about the process in the control flow shown in FIG. 6, the same process as the process of the control flow shown in FIG. 3 is attached | subjected, and the detailed description is abbreviate | omitted. In the relay station activation process according to the present embodiment, when the process of S103 ends, the response determination unit 33 performs the processes of S301 and S302. In S301, response status information is received from the base station 2. This response status information is information regarding the presence or absence of a connection request from a wireless terminal recognized by the base station 2. In the present embodiment, the wireless terminals to be recognized by the base station 2 (for example, the wireless terminals 4 and 5 have been communicating with the base station 2 until just before, but for some reason these wireless terminals and From the wireless terminals 4 and 5 when the communication is disconnected or a wireless terminal in which the moving area is set in the area R1 or R2 and wireless communication with the base station 2 is determined in advance) Information actively indicating that the connection request has not reached the base station 2 is referred to as response status information. When the process of S301 ends, the process proceeds to S302.

  In S302, based on the response status information received in S301, it is determined whether or not the base station 2 recognizes and responds to the wireless terminal that has issued the connection request detected in S103. Thereby, the presence or absence of a response to the connection request from the wireless terminal can be easily determined by using the response status information issued from the base station 2 itself. If a negative determination is made in S302, the processing after S104 is performed to start the relay operation by the relay station 3, and if an affirmative determination is made in S302, the relay station activation processing is terminated. In addition, in order to determine the response of the base station 2 more reliably, the determination process of S201 in the flow of FIG. 5 described above may be performed together. As described above, the activation of the relay station 3 is adjusted more accurately, and thus it is possible to suppress the power consumed in the relay station 3 and the frequency resources used from being unnecessarily expanded.

Next, a fourth embodiment of the activation process of the relay station 2 will be described with reference to FIG. 7 that are the same as those in the control flow shown in FIG. 3 are denoted by the same reference numerals and detailed description thereof is omitted. In the relay station activation process according to the present embodiment, when the process of S103 is completed, the determination processes of S401 and S402 are performed. In S401, similar to S201 shown in FIG. 5, the response determination unit 33 determines whether or not there is a response from the base station 2 in response to the connection request issued from the wireless terminal. If an affirmative determination is made in S401, the relay station activation process is terminated. If a negative determination is made in S401, the determination process of S402 is performed. Note that the order of the determination in S401 and the determination in S402 shown in FIG. 7 may be reversed.

  In S402, the prediction unit 34 determines whether or not the signal strength or signal quality of the connection request detected in S103 already satisfies the reference signal strength or signal quality, or issues the connection request. The strength and quality of the signal that will be received from the wireless terminal in the future, in other words, the strength and quality of the signal that will be received from the wireless terminal when the relay station 3 performs the relay operation in the future, It is determined whether it is satisfied. This determination is performed in order to ensure a good communication state between the wireless terminal and the relay station 3 in order to stably perform the relay operation performed later by the relay station 3.

  Here, the prediction of the signal strength or the like from the wireless terminal by the prediction unit 34 may be performed based on a sequence or the like when a connection request is issued from the wireless terminal. For example, when the signal strength or the like of the connection request issued from the wireless terminal increases with the passage of time, the prediction unit 34 determines the signal strength and the like at the time of processing in S402 until the substantial relay operation is started. In consideration of time, the extent to which the signal strength or the like changes at the start of the relay operation is predicted based on the rate of change of the signal strength or the like at the wireless terminal. If an affirmative determination is made in S402, the processing after S104 is performed to start the relay operation by the relay station 3, and if a negative determination is made in S402, the relay station activation processing is terminated. As described above, when the activation of the relay station 3 is more accurately adjusted and the relay operation by the relay station 3 is performed, the relay operation can be stably performed.

  In the operation of the relay station described so far, the relay operation is started by detecting the connection request signal by the wireless terminal or in addition, there is no response from the base station, or by the response status information by the base station, etc. This is an example of relaying signals between base stations. On the other hand, in the relay station, an operation in which the relay station itself behaves equivalently to the base station with respect to the wireless terminal like the above-described non-transparent mode relay station according to the IEEE 802.16 draft standard can be considered. Also in this type of relay station, the technical ideas related to the relay station described so far can be applied in the same way, the connection request signal is detected by the wireless terminal or in addition, there is no response from the base station, and the response by the base station A relay operation in a mode equivalent to that of the base station can also be started based on status information or the like. In this case, even if the wireless terminal does not obtain a connection for the first connection request, the wireless terminal issues a new connection request to the relay station that has been activated as a trigger and operates equivalent to the base station. Communication with the relay station is established, and the relay station can start communication by shifting to the transparent communication state. That is, the relay station plays a role as an alternative base station.

  For a relay station of a type that performs an operation equivalent to a base station for a wireless terminal, communication between the relay station and the base station is a wireless communication between the relay station and the base station that has been separately established. Not only that, it may be a wired communication established separately. Furthermore, when using wired communication, a relay station of a type that performs an operation equivalent to a base station for a wireless terminal, the relay destination need not be limited to the base station, as with other normal base stations, It may be a device (control network) on a communication network.

In this embodiment, as shown in FIG. 8, the base station uses the preamble signal used for establishing synchronization, transmission area information of burst data in the downlink (radio resource information used for transmission such as transmission frequency and transmission timing). Therefore, the reception area information (referred to as ULMAP information) of burst data (including random access signals) in the uplink is transmitted. On the other hand, the radio terminal receives the preamble signal, synchronizes with the radio frame of the base station, and receives ULMAP information and DLMAP information. Based on the assigned connection ID, the wireless terminal searches whether the MAP information includes transmission area information and reception area information related to the terminal, and if included, receives data in the corresponding transmission area and reception area. To do. Here, the ULMAP information also includes information designating a transmission area of the random access signal, and the wireless terminal transmits the random access signal in the transmission area designated by the information.

  As with the wireless terminal, the relay station first receives a preamble signal and performs synchronization processing, receives MAP information, and specifies a wireless resource used when transmitting a random access signal from the wireless terminal. . As shown in FIG. 9, the configuration of the relay station includes a transmission / reception unit that transmits and receives radio signals, and a control unit that controls the transmission / reception unit and exchanges transmission / reception data with the transmission / reception unit. . Hereinafter, the operation of the relay station is control executed by the control unit.

  Thereafter, MAP data (broadcast information) transmitted from the base station is not received. Preferably, the preamble is not received, but intermittent reception is performed such that the preamble for synchronization with the radio frame transmitted by the base station is once every frame or a plurality of frames.

  On the other hand, the relay station performs RA1 reception processing every frame. When a random access signal (connection request signal) is received from the wireless terminal in RA1, relay processing of the received random access signal is performed and reception processing of MAP information transmitted from the base station is started. Also, the relay station itself starts transmission / reception of the preamble signal, MAP information, and burst data (uplink, downlink) (before the start, it does not transmit / receive the preamble signal, MAP information, burst data (uplink, downlink)). At this time, a transmission area (RA2) that allows the wireless terminal to transmit a random access signal may be set in the uplink burst data.

  The relay station establishes a wireless communication path with the base station by receiving the MAP information from the base station. At that time, as in the case of the wireless terminal, a wireless communication path may be established by transmitting a random access signal to the base station (a state in which data can be transmitted and received by MAP information by resetting the connection ID or the like). Therefore, the relay station performs wireless communication with the wireless terminal by transmitting MAP information according to the scheduling in the base station or the local station, and performs a relay operation to transmit the received data to the base station. A relay operation for transmitting data received from the station to the wireless terminal is performed.

  Note that the relay station can detect that the random access signal from the wireless terminal has been detected in the RA1 as described above as a trigger for transmitting the wireless frame to the wireless terminal, but may include other conditions. For example, the fact that there is a response from the base station means that the wireless terminal and the base station can normally communicate with each other, so that the base station may not send a response signal. At that time, the base station may receive a random access signal directly from the wireless terminal, or may receive a random access signal relayed from the relay station.

  The relay station can also receive notification from the base station whether or not a response has been made to the random access signal. Although the relay station has detected a random access signal, the base station may not be able to detect it, and such a case is detected by notification from the base station, and the relay station itself also detects a preamble signal, MAP information, burst data (uplink). , Downlink) transmission / reception can also be started.

In addition, when the reception level or the reception quality of the random access signal exceeds a predetermined standard, the relay station performs a relay process on the received random access signal and starts a reception process of the MAP information transmitted from the base station. The relay station itself can also start transmission / reception of a preamble signal, MAP information, and burst data (uplink and downlink). This is because power consumption can be prevented from being wasted by receiving a random access signal from a wireless terminal remote from the relay station.

<Others>
Furthermore, this embodiment discloses the following invention. The invention disclosed in each section can be combined as much as possible as necessary.

(Appendix 1)
A relay station that relays wireless communication between a wireless terminal and a base station,
The relay communication between the base station and the wireless terminal is set in a relay standby state while being able to receive a connection request to the base station issued from the wireless terminal corresponding to the broadcast information from the base station A relay standby unit;
A connection request detection unit for detecting a connection request to the base station issued from the wireless terminal in a relay standby state by the relay standby unit;
When a connection request is detected by the connection request detection unit in the relay standby state by the relay standby unit, the relay standby state is shifted to the relay operation state, and wireless communication between the wireless terminal and the base station is relayed A relay operation unit;
A relay station for wireless communication.

(Appendix 2)
A response determination unit that determines whether or not there is a response from the base station to the connection request issued from the wireless terminal by the connection request detection unit;
The relay operation unit shifts from the relay standby state to the relay operation state when a connection request is detected by the connection request detection unit and a response from the base station to the connection request is not confirmed by the response determination unit. Relay wireless communication between the wireless terminal and the base station;
The relay station for wireless communication according to appendix 1.

(Appendix 3)
The response determination unit determines whether there is a response of the base station to the connection request based on information transmitted from the base station and information on a response status to a connection request from a wireless terminal of the base station To
The relay station for wireless communication according to appendix 2.

(Appendix 4)
The relay operation unit determines transition to the relay operation state based on the signal strength of the connection request received at the relay station after being issued from the wireless terminal, or the signal quality of the connection request.
The relay station for wireless communication according to appendix 1.

(Appendix 5)
A prediction unit that predicts the signal strength of the connection request or the signal quality of the connection request when the connection request issued from the wireless terminal is received by the relay station;
The relay operation unit determines a transition to the relay operation state based on the signal strength of the connection request predicted by the prediction unit or the signal quality of the connection request.
The relay station for wireless communication according to appendix 4.

(Appendix 6)
The relay operation unit shifts to an equivalent communication state in which a communication operation equivalent to the base station with respect to the wireless terminal is performed instead of shifting from the relay standby state to the relay operation state unit. Wireless communication between
The relay station for wireless communication according to any one of appendix 1 to appendix 5.

(Appendix 7)
The relay operation unit performs communication between the base station and the wireless communication relay station by wired communication.
The relay station for wireless communication according to appendix 6.

(Appendix 8)
The relay operation unit performs a relay operation using a predetermined control network as a relay destination instead of the base station by the wired communication.
The relay station for wireless communication according to appendix 7.

(Appendix 9)
A wireless communication system for performing wireless communication between the base station and the wireless terminal, including the relay station according to any one of Appendix 1 to Appendix 8,
In the initial synchronization signal that is transmitted and received between the base station and the wireless terminal and necessary for the initial synchronization of the wireless terminal, including the broadcast information and the connection request, in the downlink direction from the base station to the wireless terminal An area in which the initial synchronization signal can be received by the wireless terminal is set wider than an area in which the initial synchronization signal in the uplink direction from the wireless terminal to the base station can be transmitted by the wireless terminal.
Wireless communication system.

(Appendix 10)
The transmission level of the initial synchronization signal in the downstream direction is set higher than the transmission level of the initial synchronization signal in the upstream direction.
The wireless communication system according to attachment 9.

(Appendix 11)
The modulation method of the initial synchronization signal in the downlink direction is set lower than the modulation method of the initial synchronization signal in the uplink direction.
The wireless communication system according to attachment 9.

(Appendix 12)
The coding rate of the initial synchronization signal in the downlink direction is set lower than the coding rate of the initial synchronization signal in the uplink direction.
The wireless communication system according to attachment 9.

(Appendix 13)
The initial synchronization signal in the downlink direction is sent by repeated code transmission.
The wireless communication system according to attachment 9.

(Appendix 14)
Wireless communication between the base station and the wireless terminal is performed by spread spectrum communication,
The spread spectrum ratio of the initial synchronization signal in the downlink direction is set higher than the spread spectrum ratio of the initial synchronization signal in the uplink direction,
The wireless communication system according to attachment 9.

(Appendix 15)
A relay station control method for relaying radio communication between a radio terminal and a base station,
When receiving the reception area information of the random access signal transmitted from the base station, performing a control to restrict reception of the transmission area information of the burst data transmitted from the base station;
Performing a random access signal detection process according to the reception area information of the random access signal;
Detecting a random access signal transmitted from the wireless terminal, resuming reception control of transmission area information of burst data transmitted from the base station, and establishing a communication path with the base station;
Including a relay station control method.

DESCRIPTION OF SYMBOLS 1 ... Wireless communication system 2 ... Base station 3 ... Relay station 4 ... Wireless terminal 5 ... Wireless terminal R1 ... Receivable area R2 ... Transmission Possible area

Claims (10)

A wireless communication device capable of communicating with a wireless terminal,
Receiving means for receiving a connection request transmitted from the wireless terminal to the base station;
Triggered by the reception of the connection request, the to the operating state that executes the base station equivalent to the communication operation to the radio terminal, and a control means for performing control to switch from the standby state without performing the communication operation,
A wireless communication apparatus comprising: In the standby state, when the reception unit receives the connection request without transmitting notification information, the control unit performs control to switch to the operation state,
The communication information with the said radio | wireless terminal is established in the procedure similar to the said base station, when alerting | reporting information is transmitted to the said radio | wireless terminal in the said operation state, and the said connection request | requirement is received from the said radio | wireless terminal. Wireless communication device. Response determination means for determining presence or absence of a response of the base station to the connection request,
The control means switches from the standby state to the operation state when a response from the base station to the connection request is not confirmed by the response determination means after the connection request is received by the receiving means.
The wireless communication apparatus according to claim 1 or 2. The response determination means is based on information transmitted from the base station and indicating that a connection request from the wireless terminal has not arrived, and a response from the base station to the connection request is not confirmed. The wireless communication apparatus according to claim 3, wherein the determination is performed . The control means switches to the operation state when the signal strength or signal quality of the connection request received by the receiving means is a predetermined value or more.
The wireless communication apparatus according to any one of claims 1 to 4. Predicting means for predicting the signal strength or signal quality of the connection request when the connection request is received by the receiving means;
The control means switches to the operation state when the signal strength or the signal quality predicted by the prediction means is a predetermined value or more.
The wireless communication apparatus according to any one of claims 1 to 5. Means for performing a relay operation with a predetermined control network as a relay destination in place of the base station in the operation state;
The wireless communication apparatus according to claim 1, further comprising: In the operating state, communicate with the base station by wired communication,
The wireless communication apparatus according to any one of claims 1 to 7. A wireless communication system for performing wireless communication between the base station and the wireless terminal, comprising the wireless communication device according to any one of claims 1 to 8,
In the initial synchronization signal that is transmitted and received between the base station and the wireless terminal and necessary for the initial synchronization of the wireless terminal, including the broadcast information and the connection request, in the downlink direction from the base station to the wireless terminal The area where the initial synchronization signal can be received by the wireless terminal is set wider than the area where the initial synchronization signal in the uplink direction from the wireless terminal toward the base station can be received by the base station.
Wireless communication system. Wireless communication device
Receive a connection request sent from the wireless terminal to the base station,
A control method for performing control to switch to an operation state in which a communication operation equivalent to a base station is executed for the wireless terminal from a standby state in which the communication operation is not executed with the reception of the connection request.

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