Optical radio system, slave station device, and communication method

Abstract

To provide an optical fed radio system, a slave station device, and a communication method, capable of reducing a cost of a radio communication system by increasing the number of areas which can be covered by a master station.SOLUTION: An optical fed radio system comprises: one master slave station device connected to an optical cable as a slave station device 20 within an area; and a plurality of slave station devices which is not connected to the optical cable. The slave station device 20 performs a radio communication in order of a ring shape returned to a master slave station device 20a again via a plurality of slave station devices 20b to 20d from the start of the master slave station device 20a. The slave station device transmits a signal obtained by multiplying a signal from a terminal under a distribution to a received up-link signal in accordance with the order. The master slave station device 20a transmits data of a down-link from a master device 100 to the terminal under the distribution as well as transmitting the data to the slave station device 20b of the next order, receives the up-link signal from the slave station device 20d of the prior order, and transmits the data to the master device 100.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical radio system, and more particularly to an optical radio system, a slave station device, and a communication method that can increase the number of areas covered by a master station device and reduce the cost of building a wireless communication system. [Background technology]

[0002] [Prior art description: Figure 5] The optical radio device is a slave station that is connected to a master station via an optical fiber line and is a radio device that operates as a radio base station. The optical radio device is installed, for example, in a building and performs wireless communication with slave stations within the wireless communication range. In some systems, multiple slave stations are provided on the same floor (division, area).

[0003] A conventional wireless system using an optical radio device (optical radio system) will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram showing a schematic configuration example of a conventional optical radio system. As shown in FIG. 5, a conventional optical radio system (conventional radio system) includes a master station 100 and multiple slave stations 10 (slave station a (10a), slave station b (10b), slave station c (10c), and slave station d (10d)). Here, the slave stations a (10a) to d (10d) are provided in an area close to each other, such as on the same floor of a building, and the area is called area (1). In a conventional wireless system, multiple slave stations 10 are provided in areas other than area (1).

[0004] The master station 100 includes a host IF for connection to a host device, and a plurality of optical ports for connection to the slave stations 10 . In the conventional wireless system, one slave station 10 is connected to each optical port of the master station 100 via an optical cable.

[0005] Specifically, slave station a (10a) is connected to port #0, slave station d (10d) is connected to port #1, slave station c (10c) is connected to port #2, and slave station b (10b) is connected to port #3. That is, in the conventional wireless system shown in FIG. 5, area (1) alone occupies four optical ports of the master station 100.

[0006] [Related Technology] Incidentally, a conventional technique related to an optical transmission device is disclosed in Japanese Patent Laid-Open Publication No. 09-200149 entitled "Optical Communication System" (Patent Document 1). Patent Document 1 describes an optical communication system that connects the slave stations with a ring-shaped optical cable and realizes two-way communication between a master station and a plurality of slave stations at low cost. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 09-200149 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the conventional optical radio system, one optical port of the master station 100 is used for one slave station 10, which causes a problem that the number of areas that the master station 100 can cover is reduced.

[0009] Incidentally, Patent Document 1 does not mention that an order of transmission and reception is determined so that multiple sub-stations within an area perform one-way wireless communication in a ring shape, that there is one master sub-station connected to an optical cable within the area, that other sub-stations (slave sub-stations) sequentially transfer data from the master sub-station in order, and that the master sub-station multiplexes uplink signals from all sub-stations within the area and transmits them to the parent station.

[0010] The present invention has been made in consideration of the above-mentioned situation, and aims to provide an optical radio system, a slave station device, and a communication method that can increase the number of areas that can be covered by a master station and reduce the cost of building a wireless communication system. [Means for solving the problem]

[0011] The present invention, which aims to solve the problems of the above-mentioned conventional examples, is an optical radio system in which a master station device and slave station devices within an area are connected by an optical cable, and the area includes one master slave station device connected to the optical cable and multiple slave station devices that are not connected to the optical cable, and wireless communication is performed within the area in a ring order starting from the master slave station device, passing through the multiple slave station devices and returning to the master slave station device, and the slave slave station device multiplexes a signal from a subordinate terminal onto a signal received from the previous slave station device in the ring order and transmits the multiplexed signal to the next slave station device, and the master slave station device transmits data from the master station device in the ring order and transmits a signal received from the previous slave station device to the master station device.

[0012] Furthermore, the present invention is characterized in that in the wireless system, the main slave station device transmits a signal from a subordinate terminal to the master station device rather than to the slave station device next in line.

[0013] Furthermore, the present invention is characterized in that, in the above-mentioned wireless system, the main slave station device transmits downlink data from the master station device to the slave station device next in line after the main station device and also transmits it to a subordinate terminal, and multiplexes, among signals received from the slave station device preceding the main station device, a signal from the terminal onto an uplink signal, and transmits the multiplexed uplink signal to the master station device without transmitting it to the slave station device next in line after the main station device.

[0014] Furthermore, the present invention is characterized in that in the above-mentioned wireless system, the slave station device transmits a downlink signal from the received wireless signals to the next slave station device and also transmits it to the subordinate terminal, and multiplexes the signal from the terminal onto an uplink signal from the received wireless signals and transmits it to the next slave station device.

[0015] Furthermore, in the wireless system of the present invention, the main slave station device transmits a signal from a subordinate terminal to the next slave station device in order.

[0016] The present invention also provides a slave station device used in an optical remote radio system connected to a master station device by an optical cable, the slave station device including a master-slave transceiver unit connected to the optical cable for transmitting and receiving optical signals to and from the master station device, a slave station transceiver unit for wireless communication with another slave station device, a subordinate terminal transceiver unit for wireless communication with a subordinate terminal, and a switching control unit for controlling the slave station device to operate as a master slave station device when the master mode is set and as a subordinate slave station device when the slave mode is set. In this system, one master slave station device connected to an optical cable and multiple slave slave station devices not connected to the optical cable perform wireless communication in a ring-like order starting from the master slave station device, passing through the multiple slave slave station devices, and returning to the master slave station device. When operating as a slave slave station device, the slave station device multiplexes a signal received from the previous slave station device according to the ring-like order with a signal from a subordinate terminal, and transmits the multiplexed signal to the next slave station device. When operating as a master slave station device, the master station device transmits data from the master station device according to the ring-like order, and transmits a signal received from the previous slave station device to the master station device. It is characterized by the following.

[0017] The present invention also provides a communication method in an optical radio system in which a master station device and slave station devices within an area are connected by an optical cable, and wireless communication is performed in a ring-like order within the area, starting with one master slave station device connected to the optical cable, passing through a number of slave slave station devices that are not connected to the optical cable, and returning to the master slave station device, wherein the master slave station device transmits data from the master station device to the slave slave station device that is next in order after the master station device in the ring-like order, the slave slave station device multiplexes a signal from a subordinate terminal onto a signal received from the previous slave station device in the ring-like order, and transmits the multiplexed signal to the next slave station device, and the master slave station device transmits a signal received from the slave slave station device that is previous in order to the master station device. Effect of the Invention

[0018] According to the present invention, an optical radio system in which a master station device and slave station devices within an area are connected by an optical cable is provided, and the area includes one master slave station device connected to the optical cable and multiple slave slave station devices that are not connected to the optical cable. Within the area, wireless communication is performed in a ring order starting from the master slave station device, passing through the multiple slave slave station devices and returning to the master slave station device. The slave slave station device multiplexes signals from subordinate terminals onto signals received from the previous slave station device in the ring order and transmits the multiplexed signals to the next slave station device. The master slave station device transmits data from the master station device in the ring order and transmits signals received from the previous slave station device to the master station device. Therefore, if only one master slave station device is connected to the optical cable in each area, wireless communication service for the entire area can be realized, and the number of areas that can be covered by a master station device can be increased, resulting in reduced costs for constructing wireless systems.

[0019] According to the present invention, a slave station device used in an optical remote radio system connected to a master station device by an optical cable includes a master-slave transceiver unit that is connected to the optical cable and transmits and receives optical signals to and from the master station device, a slave station transceiver unit that performs wireless communication with another slave station device, a subordinate terminal transceiver unit that performs wireless communication with a subordinate terminal, and a switching control unit that sets an operating mode as master or slave, and controls the slave station device to operate as a master slave station device when the master mode is set and as a slave slave station device when the slave mode is set. In this system, one master slave station device connected to an optical cable and multiple slave slave station devices not connected to the optical cable perform wireless communication in a ring-like order starting from the master slave station device, passing through the multiple slave slave station devices, and returning to the master slave station device. When operating as a slave slave station device, the slave station device multiplexes a signal received from the previous slave station device according to the ring-like order with a signal from a subordinate terminal, and transmits the multiplexed signal to the next slave station device. When operating as a master slave station device, the master station device transmits data from the master station device according to the ring-like order, and transmits a signal received from the previous slave station device to the master station device. Since the slave station devices are the same in configuration, the master and slave station devices can be switched between different operating modes depending on the settings, which has the effect of reducing device costs and system construction costs.

[0020] Furthermore, according to the present invention, there is provided a communication method in an optical radio system in which a master station device and slave station devices within an area are connected by an optical cable, and within the area, wireless communication is performed in a ring-shaped order starting from one master slave station device connected to the optical cable, passing through a plurality of slave slave station devices that are not connected to the optical cable, and returning to the master slave station device, in which the master slave station device transmits data from the master station device to the slave slave station device that is next in order after the master station device in the ring-shaped order, the slave slave station device multiplexes a signal from a subordinate terminal onto a signal received from the previous slave station device in the ring-shaped order and transmits the multiplexed signal to the next slave station device, and the master slave station device transmits a signal received from the slave slave station device that is previous to the master station device to the master station device. Therefore, by connecting only one master slave station device to the optical cable in each area, wireless communication service can be realized for the entire area, which has the effect of increasing the number of areas that a master station device can cover and reducing the cost of constructing a wireless system. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a wireless system. [Diagram 2] FIG. 2 is an explanatory diagram showing a schematic configuration of a slave station device; [Diagram 3] FIG. 2 is an explanatory diagram showing a communication image of the present wireless system. [Figure 4] FIG. 2 is an explanatory diagram illustrating functional blocks of a slave station device; [Diagram 5] FIG. 1 is an explanatory diagram illustrating a schematic configuration example of a conventional optical radio system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. [Outline of the embodiment] An optical radio system (this radio system) according to an embodiment of the present invention is a radio system in which a parent station device and a child station device are connected by an optical cable and radio communication is performed between the child station device and a terminal under control. The child station device is set to operate as either a master child station device connected to the optical cable or a slave child station device not connected to the optical cable. The child station devices in the same area perform one-way radio transmission and reception in a ring-like order starting from the master child station device, passing through multiple slave child station devices, and returning to the master child station device again. In accordance with this order, the slave child station device multiplexes the received uplink signal with the signal from the terminal under control and transmits it to the next child station device. The master child station device transmits downlink data from the parent station device to the next slave child station device in the order and also to the terminal under control, and receives an uplink signal from the previous slave child station device and transmits it to the parent station device via the optical cable. By connecting only one master child station device to the optical cable in each area, radio communication service for the entire area can be realized, the number of areas that the parent station device can cover can be increased, and the cost of constructing a wireless system can be reduced.

[0023] [Schematic configuration of the optical radio system according to the embodiment: Figure 1] The schematic configuration of this wireless system will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram showing the schematic configuration of this wireless system. As shown in FIG. 1, the wireless system includes a parent station device (parent station, indicated as "parent" in the figure) 100, and a plurality of child station devices (child stations, indicated as "child") 20 (child station a (20a), child station b (20b), child station c (20c), child station d (20d)) provided in a plurality of areas (area (1), area (2), ...), with the parent station 100 and one child station 20 in each area being connected by an optical cable.

[0024] The master station device 100 has the same configuration as in the past, and is connected to a higher-level device and also to a plurality of slave stations 20 via optical cables. A feature of this wireless system is that the master station 100 is connected to one slave station 20 for each area via an optical cable.

[0025] In the example of FIG. 1, area (1) is provided with four slave stations 20: slave station a (20a), slave station b (20b), slave station c (20c), and slave station d (20d), but only slave station a (20a) is connected to port #0 of parent station 100 by an optical cable. The slave station 20 connected to the parent station 100 is called a master slave station (main slave station device). The child stations 20 other than the master child station are called slave child stations (subordinate child station devices). Each slave station 20 functions as a base station device of a wireless system in the same manner as in the past, and performs wireless communication with terminals under its control.

[0026] As a feature of this wireless system, a one-way ring-shaped wireless transmission / reception order is defined for the slave stations 20 in the same area (for example, the same floor of a building), starting from the master slave station, passing through multiple slave slave stations, and returning to the master slave station. In the example of FIG. 1, in area (1), the order of wireless transmission and reception is determined to be in a ring (loop) shape, starting from the master child station a (20a) connected to the parent station 100 via an optical cable and returning to the child station (a) again, as follows: child station a (20a) → child station b (20b) → child station c (20c) → child station d (20d) → child station a (20a).

[0027] Each slave station 20, regardless of whether it is a master or slave, stores information about the slave station before it (previous stage) and the slave station after it (next stage), and determines which slave station to receive from and which slave station to transmit to in wireless communication between the slave stations.

[0028] As a result, downlink data transmitted from the parent station 100 via the optical cable is received by the master child station, transferred in order from the master child station to the multiple slave child stations, and then transmitted to the terminals under each slave station. The last slave station 20 (here, slave station d (20d)) in the order (immediately before the master slave station in the ring order) transfers downlink data to slave station a (20a), which is the master slave station, but slave station a (20a) does not transmit the data to its subordinate terminals. The slave station immediately preceding the master station may be configured not to transfer downlink data to the master station.

[0029] In addition, the uplink signals from the terminals under each slave station 20 are transferred sequentially in the order of the ring, and the uplink signals from the terminals under each slave station 20 are multiplexed at the destination slave station 20 and finally transferred to the master slave station, and the master slave station transmits them to the parent station 100 via the optical cable.

[0030] That is, in area (1), the uplink signal from child station d (20d) is multiplexed with the uplink signals from child station (b) 20b, child station c (20c), and child station d (20d), and child station a (20a), which is the master child station, transmits the received uplink signal to the parent station 100.

[0031] In this case, the master slave station a (20a) may multiplex the uplink signal from its subordinate terminal onto the uplink signal from the preceding slave station d (20d), or may transmit the uplink signal from its subordinate terminal separately without multiplexing it. Furthermore, the master substation may transmit an uplink signal from its subordinate to the next slave substation, substation b (20b), to sequentially multiplex the signals among the slave substations in the area, and transmit to the parent station 100 an uplink signal received from the slave substation immediately preceding its subordinate in the ring order.

[0032] Each child station 20 is set to operate either as a master child station or as a slave child station, and operates according to the setting. The configuration and operation of the slave station 20 will be described later.

[0033] Similarly, for the other areas (2), etc., only one slave station 20 is connected to the optical cable. That is, one optical cable (one optical port) is used for one area. As a result, in this wireless system, the number of areas connectable to one master station 100 can be significantly increased compared to the conventional wireless system shown in FIG. 5, and the cost of building the wireless system can be reduced.

[0034] [Schematic configuration of slave station device 20: FIG. 2] Next, a schematic configuration of the slave station 20 will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram showing a schematic configuration of a slave station device. Fig. 2 shows a connection interface. The slave station 20 operates as either a master slave station or a slave slave station depending on the setting, and is configured to be able to operate as either. The slave station 20 operates according to the set operation mode (master or slave).

[0035] As shown in FIG. 2, the slave station 20 includes an inter-slave station interface (1) 21, an inter-slave station interface (2) 22, a parent-child interface 23, and a subordinate terminal interface 24 as connection interfaces. The slave station interface (1) (in the figure, indicated as ANT1 receiving slave station IF) 21 is connected to a receiving antenna, receives a radio signal from the slave station 20, and outputs it to a receiving processing section, which will be described later. An inter-child station interface (2) (in the figure, indicated as ANT2 inter-transmitter IF) 22 is connected to the transmitting antenna and wirelessly transmits the radio signal from the transmission processing unit.

[0036] In addition, the parent-child interface (shown as SFP0 transmit / receive IF in the figure) 23 is connected to an optical cable and performs mutual conversion between electrical and optical signals, converting downlink optical signals input from the optical cable into electrical signals, and converting uplink electrical signals into optical signals and outputting them to the optical cable.

[0037] As described above, within one area, only the child stations 20 configured as master child stations perform optical communication with the parent station 100 using the parent-child interface 23, and the child stations 20 configured as slave child stations do not perform optical communication. A subordinate terminal interface (illustrated as ANT0 transmission / reception subordinate terminal IF in the figure) 24 is connected to a wireless transmission / reception antenna, and performs wireless transmission and reception with subordinate terminals within the wireless communication range of the slave station 20 in question.

[0038] [Communication image of this wireless system: Figure 3] Next, a communication image of this wireless system will be described with reference to Fig. 3. Fig. 3 is an explanatory diagram showing a communication image of this wireless system. Here, the area (1) shown in FIG. 1 will be used as an example. In area (1), there are installed a master substation (master substation a) (20a) (shown as substation a in the figure) and slave substations (substation b) (20b), substation c (20c), and substation d (20d). The slave station a (20a) of the master is connected to the parent station 100 via an optical cable.

[0039] Also, within the communication range of the slave station a (20a), there exists (is in range) a mobile terminal (terminal) 411 as a subordinate terminal, and within the communication range of the slave station b (20b), there exists a mobile terminal 412. There may be subordinate terminals in the range of other slave stations 20, but this will not be discussed here.

[0040] First, the downlink data communication from the master station 100 will be described. Downlink (DL) data from the parent station 100 is received by the master child station a (20a) via an optical cable. The child station a (20a) wirelessly transmits the DL data to the subordinate terminal 411, and wirelessly transmits the DL data to the next (subsequent) slave child station b (20b) in a predetermined order.

[0041] The slave station b (20b) wirelessly transmits DL data to the subordinate terminal 412, and also wirelessly transmits the data to the next slave station c (20c). Similarly, when each slave station 20 receives DL data, it transmits the data to the terminal under its control and also wirelessly transmits the data to the next slave station 20 in its turn. When slave station a (20a) receives DL data from the preceding slave station d (20d), the data is not transmitted to the subordinate terminal or the next slave station b (20b) because the data has already been received.

[0042] Next, communication of uplink signals transmitted from terminals under the control of each slave station 20 will be described. The method of processing the uplink signal is different between the master and the slave. When slave sub-stations b (20b), c (20c), and d (20d) receive an uplink signal wirelessly from the previous sub-station 20, they multiplex the uplink signal from the subordinate terminal onto the received uplink signal and wirelessly transmit it to the subsequent sub-station 20.

[0043] As a result, uplink signals from terminals under the slave child station (20b), child station c (20c), and child station d (20d) are multiplexed and ultimately transmitted from child station d (20d) to the master child station a (20a). Then, the master slave station a (20a) multiplexes the uplink signal received from the preceding slave station d (20d) with the uplink signal from the terminal 411 under its control, and transmits the multiplexed signal to the parent station 100 via the optical cable.

[0044] Furthermore, the master child station a (20a) may transmit an uplink signal to the parent station 100 immediately upon receiving the uplink signal from the subordinate terminal 411 without waiting for the uplink signal multiplexed in the slave child station.

[0045] Furthermore, the master child station a (20a) may transmit an uplink signal from the terminal 411 under its control to the child station b (20b) which is the next slave child station in the order. In this case, the uplink signal from terminal 411 is transferred sequentially to the slave sub-stations, multiplexed with the uplink signals from the terminals subordinate to the slave sub-stations, and finally received by sub-station a (20a), and then transmitted from sub-station a (20a) to parent station 100. That is, in this case, the master slave station a (20a) does not perform processing for multiplexing the uplink signals from the terminals under its control.

[0046] [Functional configuration of slave station device 20: FIG. 4] Next, the functional configuration of the slave station device 20 of this wireless system will be described with reference to Fig. 4. Fig. 4 is an explanatory diagram showing functional blocks of the slave station device. As shown in FIG. 4, the slave station device 20 includes a parent-child reception processing unit (represented as SFP0 reception processing in the figure) 500, a parent-child transmission processing unit (SFP0 transmission processing) 501, a subordinate terminal transmission processing unit (ANT0 transmission processing) 502, a subordinate terminal reception processing unit (ANT0 reception processing) 503, a slave station reception processing unit (ANT1 reception processing) 504, a slave station transmission processing unit (ANT2 transmission processing) 505, an uplink multiplexing processing unit (Uplink multiplexing processing, UL multiplexing processing) 510, a TDD (Time Division Duplex) switching processing unit (1) (TDD switching processing (1)) 511, a TDD switching processing unit (2) (TDD switching processing (2)) 512, a TDD switching processing unit (3) (TDD switching processing (3)) 513, and a master / slave switching processing unit (Master / Slave switching processing) 514.

[0047] Of these functional block parts, the parent-child receiving processing unit 500 and the parent-child transmitting processing unit 501 are provided in the parent-child interface 23 shown in Figure 2, and the subordinate terminal transmitting processing unit 502 and the subordinate terminal receiving processing unit 503 are provided in the subordinate terminal interface 24. The inter-child-station transmission processing unit 504 is provided in the inter-child-station interface (2) 22, and the inter-child-station reception processing unit 505 is provided in the inter-child-station interface (1) 21. Furthermore, the TDD switching processing unit (1) 511, the TDD switching processing unit (2) 512, and the TDD switching processing unit (3) 513 are provided in a DL / UL switching processing unit (not shown).

[0048] Each functional block will be explained. The parent-child reception processor 500 inputs DL data from the DL input port and performs reception processing such as demodulation. The parent-child transmission processor 501 performs transmission processing such as modulation on the UL signal and outputs it to the UL output port.

[0049] The subordinate terminal transmission processing unit 502 performs signal processing for transmission on DL data received from the master station 100 or the preceding slave station 20, and transmits the data to the subordinate terminals of the own station. The subordinate terminal reception processing unit 503 receives UL signals from the subordinate terminals, performs reception processing, and outputs the signals to the UL multiplexing processing unit 510.

[0050] The inter-slave station reception processing unit 504 receives wireless signals (DL, UL) from the preceding slave station 20, performs reception processing, and outputs the received signals. The inter-slave station transmission processing unit 505 performs transmission processing on the DL data and UL signal, and wirelessly transmits them to the next slave station 20 in its turn.

[0051] The TDD switching processing unit (1) 511 separates the received signal into a DL signal and a UL signal based on the TDD switching timing, outputs the DL signal to the master / slave switching processing unit 514, and outputs the UL signal to the UL multiplexing processing unit 510.

[0052] UL multiplexing processing 510 multiplexes the UL signal from subordinate terminal reception processing processing unit 503 onto the UL signal from TDD switching processing unit (1) 511. Then, in the slave child station, the multiplexed signal is output to TDD switching processing unit (2) 512, and in the master child station, the multiplexed signal is output to parent-child transmission processing unit 501. That is, the UL multiplexing processor 510 switches the output destination of the multiplexed signal according to the operation mode set in the master / slave switching processor 514, which will be described later.

[0053] The TDD switching processor (2) 512 switches between the DL signal from the master / slave switching processor 514 and the UL signal from the UL multiplex processor 510 based on the TDD switching timing, and outputs the switched signal to the inter-child station transmission processor 505.

[0054] The TDD switching processing unit (3) 513 switches between the DL signal to the subordinate terminal and the UL signal from the subordinate terminal based on the TDD switching timing, wirelessly transmits the DL signal to the subordinate terminal, and outputs the UL signal to the subordinate terminal reception processing unit 503.

[0055] The master / slave switching processing unit 514 is set to the operation mode of the slave station equipment as master or slave, and controls the entire slave station equipment to operate as a master slave station or a slave slave station depending on the operation mode. The master / slave switching processing unit 514 corresponds to the switching control unit recited in the claims.

[0056] Furthermore, the master / slave switching processor 514 selects and outputs DL data according to the operation mode. Specifically, when a master is set, both DL data from the parent-child reception processing unit 500 and DL data from the TDD switching processing unit (1) 511 are input to the master / slave switching processing unit 514, and the master / slave switching processing unit 514 of the master child station selects and outputs the DL data from the parent-child reception processing unit 500. As a result, the DL data received from the master station 100 is transmitted to the terminals under the master station and to the next slave station.

[0057] Furthermore, when the master / slave switching processor 514 is set as a slave, only DL data is input from the TDD switching processor (1) 511, and the master / slave switching processor 514 outputs this DL data. When the master / slave switching processor 514 is set as a slave, the child station 20 is usually not connected to an optical cable, and no DL data is input from the parent-child reception processor 500.

[0058] [Operation of slave station 20: Figure 4] Next, the operation of the slave station 20 will be described with reference to FIG. [Slave station operation] First, the operation of the slave station will be described. The slave substation is in a state where the operating mode is set to slave in the master / slave switching processing unit 514, and performs wireless transmission and reception with subordinate terminals, receiving a wireless signal from the previous substation 20 (front stage) according to the ring order, and transmitting a wireless signal to the next substation 20 (back stage).

[0059] As shown in FIG. 4, the slave station receives DL and UL radio signals from the preceding station 20, and processes the signals in an inter-station reception processing unit 504. Then, the TDD switching processing unit (1) 511 separates the DL and UL data based on the TDD switching timing.

[0060] The separated DL data is input to the master / slave switching processing unit 514, output as is, and transmitted from the subordinate terminal transmission processing unit 502 to the subordinate terminal, and is also input to the TDD switching processing unit (2) 512, and output as a signal for transmission to the downstream slave station 20 in accordance with the TDD switching timing.

[0061] The UL signal separated by the TDD switching processor (1) 511 is input to the UL multiplex processor 510. This signal is transferred in the order of the ring and is a signal into which UL signals from terminals under the ring are multiplexed, and in the UL multiplex processor 503, the UL signals transmitted from terminals under the slave child station are multiplexed.

[0062] In a slave child station in which the operating mode is set to slave, the UL signal multiplexed by the UL multiplexing processing unit 510 is output to the TDD switching processing unit (2) 512, and is then output from the TDD switching processing unit (2) 512 as a signal for transmission to the downstream child station 20 in accordance with the TDD switching timing. Then, the inter-child station transmission processing unit 505 generates a transmission frame from the DL and UL signals input in a time-division manner, and transmits and outputs the frame to the next child station in turn. In this manner, the slave station operates.

[0063] [Master slave station operation] Next, the operation of the master slave station will be described. The master slave station is in a state where the master is set as the operation mode in the master / slave switching processing unit 514, and transmits and receives wireless signals to and from terminals under its control in the same manner as the slave slave station, and transmits wireless signals to the next slave slave station (backward stage) according to the order of the ring, and receives wireless signals from the previous slave slave station (frontward stage). Furthermore, the master slave station is connected to an optical cable to transmit and receive data to and from the parent station 100 .

[0064] The operation of the master child station will be described, focusing on the differences from the slave child station. In the master child station, the DL data received via the optical cable is processed by the parent-child reception processor 500 and input to the master / slave switching processor 514 . Also, similarly to the slave child station, the inter-child station receiving processing unit 504 receives a signal in which DL and UL data transmitted from the preceding slave child station are multiplexed, the DL and UL are separated, and the DL data is input to the master / slave switching processing unit 514.

[0065] As described above, the master / slave switching processor 514 of the master child station selects the DL data from the parent-child reception processor 500 and transmits it to the subordinate terminal and to the subsequent slave child station. In other words, the DL data transmitted from the parent station 100 is transmitted to the subordinate terminal and the subsequent slave child station.

[0066] Furthermore, the UL multiplexing processing unit 510 of the master child station multiplexes the UL signal from the terminal under its control onto the UL signal from the TDD switching processing unit (1) 511, and outputs the multiplexed UL signal to the parent-child transmission processing unit 501. In other words, the master substation multiplexes the UL signal from the subordinate terminal onto the UL signal that has been multiplexed and forwarded by multiple slave substations, and transmits the multiplexed signal to the master station 100 without transmitting it to a downstream slave substation. In this manner, the master slave station operates.

[0067] [Effects of the embodiment] According to this wireless system, in a wireless system in which a parent station device 100 and a child station device 20 are connected by an optical cable and wireless communication is performed between the child station device 20 and a terminal under its control, the child station device 20 is set to operate as either a master child station device connected to the optical cable or a slave child station device not connected to the optical cable, and a ring-shaped wireless transmission order is determined for all the child station devices 20 within the same area, starting from the master child station device 20a, passing through a plurality of slave child station devices 20b to 20d, and returning to the master child station device 20a again, and the slave child station devices multiplex the received uplink signal with a signal from the terminal under its control in accordance with the order. The master slave station device 20a then transmits the downlink data from the master station device 100 to the next slave station device 20b and to its subordinate terminals, and receives an uplink signal from the previous slave station device 20d and transmits it to the master station device 100 via the optical cable. Therefore, by connecting only one master slave station device to an optical cable in each area, wireless communication services can be realized for the entire area, and one area can be covered by one optical fiber, thereby increasing the number of areas that can be covered by the area master station device 100 and reducing the cost of building a wireless system.

[0068] Furthermore, according to this wireless system, the slave station device 20 operates as a master slave station when set as a master, and operates as a slave slave station when set as a slave, based on the operating mode set in the master / slave switching processing unit 514. This makes it possible to build a wireless system in which the master slave station and the slave slave station are devices of the same configuration, resulting in an effect of reducing device costs. [Industrial Applicability]

[0069] INDUSTRIAL APPLICABILITY The present invention is suitable for an optical feeder wireless system that can increase the number of areas covered by a master station device and reduce the cost of building a wireless communication system. [Explanation of symbols]

[0070] 20...slave station equipment (slave station), 21...inter-slave station interface (1), 22...inter-slave station interface (2), 23...parent-child interface, 24...subordinate terminal interface, 100...master station equipment (master station), 500...parent-child reception processing unit, 501...parent-child transmission processing unit, 502...subordinate terminal transmission processing unit, 503...subordinate terminal reception processing unit, 504...inter-slave station reception processing unit, 505...inter-slave station transmission processing unit, 510...uplink multiplex processing unit, 511...TDD switching processing unit (1), 512...TDD switching processing unit (2), 513...TDD switching processing unit (3), 514...master / slave switching processing unit

Claims

1. An optical wireless system in which a master station device and a slave station device within an area are connected by an optical cable, a single master station device connected to the optical cable within the area, and a plurality of slave station devices not connected to the optical cable; Within the area, wireless communication is performed in a ring-like order starting from the master slave station device, passing through the plurality of slave slave station devices, and returning to the master slave station device; the slave station device multiplexes a signal received from a subordinate terminal onto a signal received from a previous slave station device according to the ring order, and transmits the multiplexed signal to a next slave station device; A wireless system characterized in that the main slave station device transmits data from the parent station device to the slave station device next in line in the ring order, and transmits a signal received from the slave station device preceding the main slave station device to the parent station device.

2. 2. The wireless system according to claim 1, wherein the master slave station transmits a signal from a subordinate terminal to the master station instead of transmitting the signal to the slave station next in line.

3. 3. The wireless system according to claim 1, wherein the main slave station device transmits downlink data from the master station device to the slave station device next in line after the main slave station device and also transmits the data to a subordinate terminal, multiplexes a signal from the terminal onto an uplink signal received from the slave station device preceding the main slave station device, and transmits the multiplexed uplink signal to the master station device without transmitting it to the slave station device next in line after the main slave station device.

4. A wireless system according to any one of claims 1 to 3, characterized in that a subordinate slave station device transmits a downlink signal from among the received wireless signals to the next slave station device and also transmits it to a subordinate terminal, and multiplexes a signal from the terminal onto an uplink signal from among the received wireless signals, and transmits it to the next slave station device.

5. 2. The wireless system according to claim 1, wherein the primary slave station device transmits a signal from a subordinate terminal to the next slave station device in turn.

6. A slave station device used in an optical remote radio system connected to a master station device by an optical cable, a parent-child transceiver unit that is connected to an optical cable and transmits and receives optical signals to and from the parent station; an inter-slave station transmitting / receiving unit for wirelessly communicating with another slave station device; A subordinate terminal transceiver unit that performs wireless communication with a subordinate terminal; a switching control unit that controls the operation mode so that a master or slave is set, the operation mode being such that the slave station equipment operates as a master when the master is set, and operates as a slave station equipment when the slave is set, A master slave station device connected to the optical cable and a plurality of slave slave station devices not connected to the optical cable perform wireless communication in a ring-like order starting from the master slave station device, passing through the plurality of slave slave station devices, and returning to the master slave station device, When operating as the slave station device, the slave station device multiplexes a signal received from a subordinate terminal onto a signal received from a previous slave station device according to the ring order, and transmits the multiplexed signal to the next slave station device; When operating as the main slave station device, the slave station device transmits data from the parent station device to the slave station device next in line in the ring order, and transmits a signal received from the slave station device preceding the parent station device to the parent station device.

7. A communication method in an optical radio system in which a master station device and a slave station device within an area are connected by an optical cable, comprising: Within the area, wireless communication is performed in a ring-like order starting from one master slave station device connected to the optical cable, passing through a plurality of slave slave station devices not connected to the optical cable, and returning to the master slave station device, the master slave station device transmits the data from the master station device to the slave slave station device that is next in order to the master station device in accordance with the ring order; the slave station device multiplexes a signal received from a subordinate terminal onto a signal received from a previous slave station device according to the ring order, and transmits the multiplexed signal to a next slave station device; A communication method comprising the steps of: transmitting, to said master station device, a signal received from a slave station device that is preceding said master station device in turn.

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