JP4988492B2 - Optical transmission system - Google Patents

Description

  The present invention relates to an optical transmission system used in a wireless communication system, and in particular, in a system in which slave units and HUBs are connected in multiple stages, it is possible to measure a system delay amount before starting operation to prevent problems after system operation. The present invention relates to an optical transmission system capable of providing an appropriate service.

[Description of Prior Art]
In digital mobile communication, a high-power transmission amplifier is used. In the past, the transmission amplifier was often installed on the same rack as the base station. However, in recent years, the transmission / reception amplifier having the function of the radio unit and the transmission amplifier is separated from the base station, and both are connected by an optical fiber. A configuration is also used. Such a configuration is referred to as ROF (Radio On Fiber) or RRH (Remote Radio Head).
By using ROF and RRH, there is an effect that communication quality is improved, operation cost is reduced, and maintenance is facilitated.

[Configuration example of base station and transmission / reception amplifier: FIG. 7]
A configuration example of a base station and transmission / reception amplifiers in ROF and RRF will be described with reference to FIG. FIG. 7 is a schematic explanatory diagram illustrating a configuration example of a base station and a transmission / reception amplifier, where (a) is an example of a star topology and (b) is an example of a chain topology.
As shown in FIG. 7A, in the star type, transmission / reception amplifiers (“TRX-AMP” in the figure) 57 a and 57 b are connected to a base station 55 via an optical fiber 56.

The base station 55 is mounted with an optical interface (I / F), converts a signal from the base station 55 to the transmission / reception amplifier 57 from an electric signal to an optical signal, transmits the optical signal through the optical fiber 56, and transmits / receives the amplifier. The optical signal received from 57 is converted into an electrical signal.
The optical fiber 56 transmits an optical signal and has standards such as CPRI and OBSAI.

  The transmission / reception amplifier 57 includes an opto-electric conversion unit and an electro-optical conversion unit (not shown) for converting an optical signal and an electric signal, and receives transmission data transmitted from the base station 55 via the optical fiber 56. The amplified data is output from the antenna, and the received data received by the antenna is amplified and transmitted to the base station 55 via the optical fiber 56.

  In the star type, a transmission / reception amplifier 57 as a slave station is connected to the optical interface of the base station 55.

Further, as shown in FIG. 7B, in the chain type, a transmission / reception amplifier 57a is connected to the base station 55 via an optical fiber 56, and a transmission / reception amplifier 57b is further connected to the transmission / reception amplifier 57a via an optical fiber. Has been.
That is, the transmission / reception amplifier 57b is connected to the base station 55 via the transmission / reception amplifier 57a.

The transmission / reception amplifier 57a used in the chain type has two ports, a slave port and a master port. The slave port performs transmission / reception with a higher-order base station 55, and the slave port has a lower-order. Transmission / reception with the transmission / reception amplifier 57b.
The slave port is an input / output port for operating with a connection destination clock, and the master port is an input / output port for operating the connection destination with an output clock.

[Outline of optical transmission system: Fig. 8]
In addition, the optical transmission system is a base station, repeater, and slave unit connected by optical fiber or coaxial cable. The signal output from the base station is transmitted as it is to a remote dead zone to provide a mobile communication service area. Is intended to expand. Generally, an optical fiber is used between the base station and the repeater.

Here, an outline of the optical transmission system will be described with reference to FIG. FIG. 8 is a schematic explanatory diagram showing an outline of an optical transmission system.
As shown in FIG. 8, an optical transmission system includes a base station (“BTS” in the figure) 61, an optical interface (“BTS-IF” in the figure) 62, an optical fiber 63, a repeater 64, and a plurality of It is comprised from the subunit | mobile_unit 65. FIG.

The base station 61 is a base station of the mobile radio system, and transmits and receives high frequency signals.
The optical interface 62 receives a high-frequency signal from the base station 61 through a coaxial connection, converts it into an optical signal, and transmits it to the repeater 64 via the optical fiber 63. The optical interface 62 converts the optical signal received from the repeater 64 received via the optical fiber 63 into an electrical signal and transmits it to the base station 61 via a coaxial cable.

The repeater 64 is installed at a location far away from the base station 61, converts the optical signal received from the optical fiber 63 into an electrical signal, and distributes and outputs it to the slave units 65-1, 65-2, ... 65-n. . Further, the repeater 64 multiplexes the electrical signals received from the slave units 65-1, 65-2,... 65-n, converts them into optical signals, and transmits them to the optical interface 62 via the optical fiber 63.
In this example, the repeater 64 and the slave unit 65 are connected by a coaxial cable, but an optical fiber is used when the distance between the repeater 64 and the slave unit 65 is long.

The subunit | mobile_unit 65 amplifies the high frequency signal received from the relay machine 64, outputs it as a radio signal via an antenna, receives the radio signal transmitted from the mobile terminal, amplifies it, and outputs it toward a relay machine .
As described above, the optical transmission system enables mobile communication even in a dead zone where a wireless signal does not reach, such as in a building, and can expand the service area of the mobile wireless system.

  Although not shown, there is also an optical transmission system having a chain type configuration in which a plurality of slave units 65 or hubs (HUBs) are connected to a repeater (master unit) 64 connected to a base station in multiple stages. In this case, the slave unit and the HUB are provided with a slave port and a master port.

[Prior art documents]
In addition, as a prior art regarding the optical transmission system, there is JP-A-2003-163634 (Patent Document 1).
In Patent Document 1, a high-frequency signal is down-converted by a frequency converter using a local signal LO, converted to an optical signal having a first wavelength by a first laser diode, and further LO is converted to a second signal by a second laser diode. There is described an optical transmission device that converts an optical signal of a wavelength, combines an optical signal of a first wavelength and an optical signal of a second wavelength with a coupler, and transmits the resultant signal to an optical fiber transmission line.

JP 2003-163634 A

  However, in a conventional optical transmission system, when many slave units and HUBs are connected in a chain type, there is a possibility that a delay amount exceeding the service area of the base station may occur because long-distance optical transmissions overlap.

  For example, some SFP (Small Form-Factor Pluggable) modules that are generally used in optical transmission are capable of optical transmission of 20 km or more. For example, the SFP is connected to a repeater (base unit) by an optical fiber. The slave unit at the stage has a delay of 20 km, but the slave unit at the fourth stage can be as long as 80 km, and normal operation is not possible unless it is a base station capable of cell search of 80 km.

  In the conventional optical transmission system, there is no means for measuring the transmission delay amount in advance, and it is found that normal service cannot be performed for the first time after the system starts operating. There is a problem that work is required, and it may take a lot of time and labor to start normal operation of the system.

  The present invention has been made in view of the above circumstances, and by calculating and displaying a list of transmission delays before starting the operation of the system, if there is a problem, it can be improved before starting the service, and at low cost and in a short time. An object of the present invention is to provide an optical transmission system capable of realizing a highly reliable system.

The present invention for solving the problems of the conventional example described above is a base station of a radio communication system, and a radio signal received from the base station is converted into an optical signal and output, and the received optical signal is converted into a radio signal. And a slave unit that outputs the received optical signal to a radio signal, amplifies it, and outputs it from the antenna. A plurality of slave units are connected to the repeater in a chain form by an optical fiber. a light transmission system, comprising a maintenance device that is connected to the relay device, stores the delay parameter indicating a specific delay time of the advance device internal to the relay unit and the slave unit, the delay parameters of the repeater, the relay This is a parameter that indicates the delay time from the wireless signal input terminal of the unit to the output of the optical signal. The delay parameter of the slave unit returns the optical signal reference signal from the host device to the host device as an optical signal. The first parameter that is the delay time until the second signal, the second parameter that is the delay time until the optical signal received from the host device is output to the lower device, and the optical signal received from the host device is converted into a radio signal. This is the third parameter, which is the delay time until the signal is output from the antenna. When the system is started, the relay unit and the slave unit receive the reference signal sent to the lower device and the reference signal returned from the lower device. was measured as optical line delay amount in the time difference optical fiber connected to the lower of the timing, the slave unit, the first is stored, second, it reads out the third parameter, the measured optical line transmitted to the relay unit with delay, the relay machine, first the optical time line delay amount optical line delay and a plurality of slave unit was measured by itself measured, its delay parameter and a plurality of slave unit, Second And a third parameter is transmitted to the maintenance device, the maintenance device includes a display unit, and the optical line delay amount repeater or slave unit was measured, the lower of which is connected to the lower of the repeater or slave unit Find the difference with the first parameter of the slave unit, calculate the half of the difference as the transmission delay amount of the optical fiber connected to the relay unit or the lower level of the slave unit, delay parameter of the relay unit, Transmission delay amounts of all optical fibers passing from the repeater to any slave unit that outputs the antenna, second parameters of all slave units passing from the repeater to the slave unit, and any slave units The sum of the time and the third parameter of the unit is calculated as a delay time from the radio signal input of the repeater to the antenna output of the arbitrary slave unit , and the transmission delay amount of each optical fiber , possible to display the delay time in Table radical 113 It is characterized by.

The present invention also relates to a base station of a radio communication system, and a repeater that converts a radio signal received from the base station into an optical signal and outputs the optical signal, and converts the received optical signal into a radio signal and outputs the radio signal to the base station. A slave unit that converts the received optical signal into a radio signal, amplifies it, and outputs it from the antenna, and a maintenance device connected to the repeater. A method for calculating a transmission delay time in an optical transmission system, wherein a delay parameter indicating an intrinsic delay time inside the apparatus is stored in advance in a repeater and a slave, and the delay parameter of the repeater is a radio signal of the repeater This parameter indicates the delay time until the optical signal is output from the input terminal. The slave unit's delay parameter is the response time from the reception of the optical signal reference signal from the host device to the host device. The first parameter that is the delay time of the second, the second parameter that is the delay time until the optical signal received from the host device is output to the lower device, and the optical signal received from the host device are converted into radio signals. a third parameter is a delay time until the output from the antenna, at system startup, the relay unit and the slave unit has received the timing of transmitting the reference signal to the lower-level device, a reference signal sent back from the lower device The time difference from the timing is measured as the optical line delay amount in the optical fiber connected at the lower level, and the slave unit reads the stored first, second, and third parameters, and the measured optical line delay amount Together with the optical line delay amount measured by itself and the optical line delay amount measured by the plurality of slave units, the own delay parameters, and the first, second, and second of the plurality of slave units. Of the parameters sent to the maintenance device, the maintenance device, repeater or slave unit of the first parameter of the slave unit of the lower connected to the lower light line delay amount measured repeater or slave unit obtains a difference, half the time of the difference, is calculated as a transmission delay amount of the optical fibers connected to the lower rELAY machine or slave unit, the delay parameters of the repeater, any of the antenna outputs from the repeater The sum of the transmission delay amount of all optical fibers passing through to the slave unit, the second parameter of all slave units passing from the repeater to any slave unit, and the third parameter of any slave unit Is calculated as a delay time from the radio signal input of the repeater to the antenna output of the arbitrary slave unit.

According to the present invention, the maintenance device connected to the repeater is provided, the delay parameter indicating the inherent delay time inside the device is stored in advance in the repeater and the slave, and the delay parameter of the repeater is This parameter indicates the delay time from the wireless signal input terminal until the optical signal is output. The delay parameter of the slave unit is the time from when the optical signal reference signal is received from the host device until the optical signal is returned to the host device. The first parameter that is the delay time, the second parameter that is the delay time until the optical signal received from the host device is output to the lower device, and the optical signal received from the host device are converted into a radio signal and the antenna. a third parameter is a delay time until the output from the system startup, the relay unit and the slave unit is the timing that transmitted the reference signal to the lower unit, it is returned from the lower device Was measured as optical line delay time difference between the timing of receiving a reference signal in an optical fiber connected to the lower, the slave unit, first, second, reads out the third parameter stored, measured has been transmitted to the relay apparatus with the optical line delay, repeater is an optical time line delay amount optical line delay and a plurality of slave unit was measured by itself measured, its delay parameter and a plurality of slave unit first, second, and third parameters to send to the maintenance device, the maintenance device includes a display unit, and the optical line delay amount repeater or slave unit was measured, the repeater or slave unit Find the difference with the first parameter of the slave unit connected to the lower level, calculate the half of the difference as the transmission delay amount of the optical fiber connected to the relay unit or the lower level of the slave unit, Repeater delay parameters and repeaters Transmission delay amount of all optical fibers passing through to any slave unit that outputs, second parameter of all slave units passing from the repeater to the arbitrary slave unit, and the first parameter of any slave unit 3 of the time of the sum of the parameters, calculated as a delay time from the radio signal input of the repeater to the antenna outputs of the arbitrary slave unit, the transmission delay amount of each optical fiber, delay time of each child machine preparative since the optical transmission system are listed in Table radical 113 can grasp the amount of delay before operation of the system, can be improved before starting the service operation if any defects, low cost and short There is an effect that a highly reliable system can be realized in time.

[Summary of Invention]
Embodiments of the present invention will be described with reference to the drawings.
In the optical transmission system according to the embodiment of the present invention, a slave unit or HUB, which is a subordinate device, measures the optical line delay time at the master port, and the measured optical line delay time is stored in each device in advance. Device-specific delay parameters are sent to the host device, and the repeater (master unit) collects the optical line delay time and parameters from each device and outputs them to the maintenance tool (MT) connected to the repeater. , MT calculates the delay amount from the input end of the repeater to the wireless output end of each device and the maximum delay amount of the system, and displays them together with a schematic diagram of the system. It is possible to know how much delay occurs, and to improve in advance when the system becomes a delay that cannot operate normally, thereby realizing a highly reliable system.

[Configuration of Optical Transmission System of Embodiment: FIG. 1]
FIG. 1 is a schematic configuration diagram showing an example of an optical transmission system (this apparatus) according to an embodiment of the present invention.
As shown in FIG. 1, this apparatus includes a base station (described as “BTS” in the figure) 1, a repeater (master unit) 2, slave units 4 a to 4 d, a HUB 5, and a maintenance tool (MT) 6. The relay unit 2 and the slave unit 4, the slave units 4, the slave unit 4 and the HUB 5 are connected by an optical fiber 3. The maintenance tool 6 corresponds to a “maintenance device” recited in the claims.

The repeater 2 relays communication between the base station 1 and the slave unit 4, is coaxially connected to the base station 1, converts a radio signal received from the base station 1 into an optical signal, and outputs the optical signal to the optical fiber 3. At the same time, the optical signal received from the optical fiber 3 is converted into a radio signal and output to the base station 1.
The repeater 2 includes a plurality of ports (master ports) 22 to which the optical fiber 3 is connected, and a plurality of slave units 4 and HUBs 5 can be connected. In the example of FIG. 1, the slave units 4 a and 4 b are connected to the master port 22 of the relay unit 2.
As a feature of this system, the repeater 2 stores a parameter indicating a delay inside the apparatus in a nonvolatile memory (not shown) provided therein. The parameters will be described later.

  Although not shown, the slave unit 4 includes an optical signal transmission / reception unit that transmits / receives an optical signal, an optical interface unit that performs mutual conversion between an optical signal and a radio signal, a signal processing unit that performs signal processing of the radio signal, A radio unit that transmits / receives and amplifies a radio signal, a control unit that controls the entire apparatus, and a storage unit that stores data, and performs optical communication with a higher-level device and a lower-level device, and a mobile station (see FIG. (Not shown) is a transmission / reception amplifier (TRX-AMP) that performs wireless communication.

  Then, the slave unit 4 converts the optical signal received from the repeater 2 into a radio signal, amplifies and outputs the signal wirelessly, amplifies the radio signal received from the mobile station, converts the signal into an optical signal, and repeats the repeater 2. Send to. At the same time, the handset 4 outputs the optical signal received from the repeater 2 to the subordinate handset 4 or the HUB 5.

  And the subunit | mobile_unit 4 is equipped with two types of ports, the slave port 41 connected to a high-order apparatus, and the master port 42 connected to a low-order apparatus as an optical signal transmission / reception part, and can construct | assemble a chain type system. is there.

The HUB 5 distributes the signal received from the relay device 2 or the slave unit 4 of the higher-level device and transmits the signal to the slave unit 4 or the HUB 5 of the lower-level device, and the signal received from the slave unit 4 or the HUB 5 of the lower-level device. Multiplex and transmit to the host device.
The HUB 5 includes one slave port 51 connected to a higher-level device and a plurality of master ports 52 connected to a plurality of lower-level devices.
As described above, the use of the handset 4 and the HUB 5 that can be connected in a chain type increases the degree of freedom in system design.

  Further, as a feature of the present system, each lower-level device (slave unit 4 and HUB 5) stores parameters necessary for calculating the delay amount in MT 6 in a nonvolatile memory (not shown). The parameter indicates a fixed delay amount generated inside the apparatus, and will be described in detail later.

  Further, as a feature of this system, each subordinate apparatus measures the delay amount (optical line delay amount) of the optical fiber 3 connected to the subordinate apparatus when the system of the system is started up, and the optical line delay amount and non-volatile The parameters stored in the memory are transmitted to the repeater 2. Operations of the slave unit 4 and the HUB 5 will be described later.

Furthermore, as a feature of this system, the master port of each device (relay unit 2, slave unit 4, HUB 5) outputs a reference timing for measuring the optical line delay amount.
As the reference timing, for example, a K28.5 special code generally used in serial transmission is used. Thereby, the circuit scale can be reduced. The reference timing is output at a constant cycle.

The MT 6 is an information processing apparatus such as a personal computer, and includes a control unit, a storage unit, an input unit, a display unit, and the like (not shown).
The control unit is composed of a CPU (Central Processing Unit) and includes various processing means for realizing processing for displaying a delay amount in the present system.
The storage unit includes a hard disk, a main memory, and the like, and stores a processing program executed by the control unit. Various processing means are realized by the control unit expanding and starting the processing program stored in the hard disk in the main memory.
In addition, the storage unit of the MT 6 stores in advance display data of a system schematic diagram for displaying a schematic configuration of the entire system and display data for displaying a transmission delay.

[Outline of operation of this system: Fig. 2]
An outline of the operation of this system will be described with reference to FIG. FIG. 2 is an explanatory diagram showing an outline of the operation of this system.
In MT6, when the system of the present apparatus is started, the control unit acquires necessary numerical information from the repeater 2, and based on the numerical information, the delay from the input end of the repeater 2 to the output end of each subordinate apparatus is calculated. It is calculated and displayed on the display unit together with the system schematic diagram. Further, the control unit of MT6 calculates and displays the maximum delay amount of the system.
Necessary numerical information is parameters stored in the repeater 2, the slave unit 4, and the HUB 5, and the optical line delay amount measured by each of these devices.

For example, in the example of FIG. 2, the radio signal output from the base station 1 is input to the input terminal of the repeater 2 and then converted into an optical signal, and the slave unit 4a, the HUB 5, the slave unit 4c, and the optical fiber 80km. The delay until the signal is input to the slave unit 4d via (20 km × 4), converted into a radio signal again by the slave unit 4d and output from the antenna becomes the maximum system delay amount.
By displaying the maximum delay amount, it is possible to easily determine whether or not the system can operate normally.

[Parameters and optical line delay amount: Fig. 3]
The parameters stored in the lower device of this system will be described with reference to FIG. FIG. 3A is a schematic explanatory view showing parameters of Toffset, Tcascade, and Tsigdly, and FIG. 3B is a schematic explanatory view showing an optical line delay amount (Tswdly).
As shown in FIG. 3A, there are three types of parameters stored in the nonvolatile memory of the handset 4: Toffset, Tcascade, and Tsigdly.
Toffset # n is the time from when slave unit #n (or HUB # n) receives the reference timing signal from the higher-level device at slave port 41 to output the reference timing signal from slave port 41 to the higher-level device. Toffset corresponds to the “first parameter” in the claims.

  Tcascade # n is the time from when slave unit #n (or HUB # n) receives the reference timing signal from the higher-level device at slave port 41 and outputs the reference timing signal from master port 42 to the lower-level device. is there. Tcascade corresponds to “second parameter” in the claims.

Also, Tsigdly # n receives the reference timing signal from the host device at slave port 41 by slave unit #n, performs digital signal processing by a DSP (Digital Signal Processor), and amplifies it by a radio unit (RF in the figure) It is time until it outputs from an antenna. Tsigdly corresponds to “third parameter” in the claims.
The number (#n) given to the Toffset, Tcascade, and Tsigdly parameters is an identification number indicating which device in the system the parameter is.
The HUB 5 stores Toffset and Tcascade parameters.

Next, parameters of the repeater 2 will be described.
The parameter of the repeater 2 is TsigdlyP, which is the processing delay time from the input of the radio signal output from the base station 1 to the repeater 2 until the output from the master port as an optical signal. . TsigdlyP is stored in the non-volatile memory of the repeater 2, and corresponds to “relayer parameter” in the claims.

Next, measurement of the optical line delay amount of this system will be described with reference to FIG.
As shown in FIG. 3B, the optical line delay amount (Tswdly) is measured at the master port of the repeater 2, the slave 4 and the HUB 5. Here, a slave unit will be described as an example.
Slave unit # n-1 has a time difference between the time at which master port 42 outputs the reference timing signal to the lower level device and the time at which master port 42 receives the reference timing signal output by the lower level device at master port 42. Measure (Tswdly # n). Then, the measured Tswdly # n is transmitted to the repeater 2 together with the other parameters described above.
The optical line delay amount Tswdly can also be identified by the number (#n) attached to which optical fiber in the system.

[Optical line delay (Tswdly) calculation unit: Fig. 4]
Next, the optical line delay amount (Tswdly) calculation unit of the repeater 2, the slave 4, and the master port of the HUB 5 will be described with reference to FIG. FIG. 4 is a block diagram showing the configuration of the optical line delay amount (Tswdly) calculation unit of the master port of the slave unit 4. Although the slave unit 4 will be described as an example here, the optical line delay amount (Tswdly) calculation units of the repeater 2 and the HUB 5 have the same configuration and operation.
As shown in FIG. 4, the optical line delay amount calculation unit of the master port 42 of the slave unit 4 includes a reference timing generation unit 422, a parallel / serial conversion unit (P / S) 423, and an electro-optical conversion unit (E / O) 424, a photoelectric conversion unit (O / E) 425, a serial / parallel conversion unit (S / P) 426, and a time difference measurement unit 427. In addition to the master port, the slave unit 4 is provided with a control unit 43 and a nonvolatile memory 44 for storing parameters.

The reference timing generation unit 422 generates a reference timing at a constant cycle.
The time difference measuring unit 427 inputs a reference timing (transmission reference timing) to be transmitted and a received reference timing (reception reference timing), and measures a time difference between them.

The master port 42 of each device measures the optical line delay (Tswdly) when the system is started. The operation of measuring the optical line delay will be described.
The reference timing generation unit 422 generates a reference timing at a constant period, and outputs the reference timing to the parallel / serial (P / S) conversion unit 423 and the time difference measurement unit 427 as the transmission reference timing.
The parallel / serial conversion unit (P / S) 423 converts the input parallel signal into a serial signal, and the electro-optical conversion unit (E / O) 424 converts the electric signal into an optical signal, and converts the optical fiber. To the slave unit 4 or the HUB 5 of the lower level device.

  Also, the optoelectric conversion unit (O / E) 425 converts an optical signal received from the lower apparatus via an optical fiber into an electric signal, and the serial / parallel conversion unit (S / P) 426 converts the electric data of the serial data. The signal is converted into a parallel signal and output to the time difference measuring unit 427 as a reception reference timing.

  The time difference measurement unit 427 measures the time difference between the transmission reference timing generated from the reference timing generation unit 422 and the reception reference timing input from the serial / parallel conversion unit (S / P) 426, and the measurement result is transmitted to the optical line. It outputs to the control part 43 as delay amount (Tswdly).

  The control unit 43 reads the Toffset, Tcascade, and Tsigdly parameters from the nonvolatile memory 44 and transmits them to the repeater 2 through the slave port 41 together with the optical line delay amount (Tswdly). The transmission data includes data such as an identification number for specifying the transmission source.

Since the repeater 2 and the HUB 5 have a plurality of master ports, the above-described measurement of the optical line delay amount is performed on all the master ports to which the optical fibers are connected.
The control unit of the repeater 2 receives the optical line delay amount and parameters transmitted from a plurality of lower-level devices, and stores the optical line delay amount measured by the repeater 2 and the repeater 2. Output to MT6 together with parameters.

[Operation of this system: Fig. 5]
Next, the operation of this system will be described with reference to FIG. FIG. 5 is a schematic explanatory diagram showing the operation of this system.
When the system is activated (S0), the repeaters, slave units, and HUBs in the system measure the optical line delay (Tswdly) at the respective master ports by the method described with reference to FIG. The area is held (S11 to S14).

  And the control part of each apparatus reads a parameter from a non-volatile memory. Here, the control unit of the repeater 2 reads the parameter TsigdlyP (S21). Further, the control units of the slave units # 1,.

And the control part of a low-order apparatus transmits the measured optical line delay amount and the read parameter to the repeater 2 (S31-S33).
The control unit of the repeater 2 receives the optical line delay amount and parameters transmitted from the subordinate apparatus, transmits them to the MT 6, and transmits Tswdly # 1 measured by the repeater 2 and TsigdlyP read from the nonvolatile memory to the MT 6. (S41).

In MT6, the transmission delay amount of each optical fiber and the delay amount to the antenna output of each slave unit are calculated based on the received optical line delay amount and parameters (S51), and displayed together with the system schematic diagram (S52). .
In this way, the operation of this system is performed.

[Calculation of delay amount]
Next, a delay amount calculation method in MT6 will be described.
In MT6, based on the numerical value acquired from the repeater 2, the transmission delay amount of each optical fiber and the delay amount from the input end of the repeater 2 to the wireless output end of each slave unit are calculated.
[Optical fiber transmission delay calculation]
The transmission delay amount (Toptdly) of the optical fiber is represented by half of the time (μsec) obtained by subtracting Toffset from the optical line delay amount (Tsigdly) measured at the master port.
That is, Toptdly # n = (Tsigdly # n−Toffset # n) × 1/2.

[Delay calculation from master unit input terminal to slave unit output terminal]
The delay amount to each child device output terminal is the time until the wireless signal input by the relay device 2 is output from the antenna of each child device.
The delay amount T # 1 of the slave unit # 1 includes the fixed delay (TsigdlyP) inside the repeater 2, the transmission delay of the optical fiber connecting the repeater 2 and the slave unit # 1, and the input terminal of the slave unit # 1. To the wireless output end (Tsigdly # 1) is added,
T # 1 = TsigdlyP + Toptdly # 1 + Tsigdly # 1.

Also, the delay amount T # 2 of the slave unit # 2 is the fixed delay (TsigdlyP) in the repeater 2, the transmission delay of the optical fiber connecting the repeater 2 and the slave # 1, and the internal number of the slave # 1. Because the delay of the optical signal (Tcascade # 1) and the delay from the input terminal of the slave unit 2 to the wireless output terminal (Tsigdly # 2) is added,
T # 2 = TsigdlyP + (Toptdly # 1 + Toptdly # 2) + (Tcascade # 1 + Tsigdly # 2)

Similarly, the delay amount T # n of the slave unit #n is
T # n = TsigdlyP + (Toptdly # 1 + Toptdly # 2 + ... + Toptdly # n) +
(Tcascade # 1 + Tcascade # 2 +… Tcascade # n-1 + Tsigdly # n)
In the same manner, the delay amount in all the lower devices in the system is calculated.
When HUB5 is included in the system, the Tcascade of HUB5 is added to the delay amount of the slave unit lower than HUB5.
Further, the MT 6 of this system calculates the delay amount in all the slave units, and selects the maximum delay amount among them.

[Display example: Fig. 6]
Next, a display example of the delay amount in MT6 will be described with reference to FIG. FIG. 6 is an explanatory diagram illustrating a display example of the delay amount.
As shown in FIG. 6, in MT6, the calculated transmission delay amount of the optical fiber and the delay amount until the signal input from the repeater is output from the antenna of the slave unit are listed on the schematic diagram of the system. It is trying to display.
As a result, it is possible to confirm how much delay occurs at the wireless output terminal of each slave before the system operation is started.
Further, by displaying the maximum delay amount, the maximum delay amount in the system can be known at a glance, so that it is possible to immediately know whether or not there is a possibility of malfunction in system operation.

[Effect of the embodiment]
According to the optical transmission system according to the embodiment of the present invention, the slave units are connected in a chain type, and as a parameter, the relay station has a fixed delay from the input end of the radio signal from the base station to the output end of the optical signal. TsigdlyP is stored, Toffset is the time from when the slave unit receives the reference timing signal from the host device at the slave port and outputs the reference timing signal from the slave port to the host device, and from the host device at the slave port Tscade, which is the time from receiving the reference timing signal to outputting the reference timing signal from the master port to the lower device, and Tsigdly, which is the time from receiving the reference timing signal from the upper device to the slave port and outputting from the antenna When the system is started, the repeater and each slave unit are connected to the master port. Measure the total time Tswdly, each slave unit transmits the measured optical line delay time and stored parameters to the repeater, and the repeater measures the optical line delay time measured by TsigdlyP, the repeater and the slave unit, and each The slave unit parameters are transmitted to the maintenance tool 6, and the maintenance tool 6 determines the transmission delay time of each optical fiber and the delay time to the wireless output terminal of each slave unit based on the received optical line delay time and parameters. Since it is an optical transmission system that calculates and displays, it is possible to know how much delay will occur before the start of system operation, and to determine in advance whether cell search of the base station is possible. In some cases, measures can be taken so that service operation can be started after the system is ready for normal operation. There is an effect that a highly reliable system can be realized at low cost and in a short time.

  Further, according to the present system, the maintenance tool 6 displays the maximum delay time of the system, so that the operator can easily determine whether or not a failure occurs based on the maximum delay time. effective.

  The present invention is an optical transmission in which a system delay amount is measured before the start of operation in a system in which slave units and HUBs are connected in multiple stages, so that problems after the system operation can be prevented and an appropriate service can be provided. About the system.

It is a schematic block diagram which shows an example of the optical transmission system (this apparatus) which concerns on embodiment of this invention. It is explanatory drawing which shows the outline | summary of operation | movement of this system. (A) is a schematic explanatory view showing parameters of Toffset, Tcascade, and Tsigdly, and (b) is a schematic explanatory view showing an optical line delay amount (Tswdly). FIG. 6 is a block diagram illustrating the configuration of an optical line delay amount (Tswdly) calculation unit of a master port of a handset 4; It is a model explanatory view which shows operation | movement of this system. It is explanatory drawing which shows the example of a display of delay amount. It is a model explanatory drawing which shows the structural example of a base station and a transmission / reception amplifier, (a) is a star type (Star topology), (b) is an example of a chain type (Chain topology). It is a schematic explanatory drawing which shows the outline | summary of an optical transmission system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Base station, 2 ... Relay machine (master machine), 3 ... Optical fiber, 4 ... Slave machine, 5 ... HUB, 6 ... Maintenance tool (MT), 41, 51 ... Slave port, 22, 42, 52 ... Master 422 ... Parallel / serial converter, 424 ... Electro-optical converter, 425 ... Photo-electric converter, 426 ... Serial / parallel converter, 427 ... Time difference measuring part, 43 ... Control part, 44 ... Non-volatile memory, 55 ... Base station, 56 ... Optical fiber, 57 ... Transceiver amplifier, 61 ... Base station, 62 ... Optical interface, 63 ... Optical fiber, 64 ... Repeater, 65 ... Slave unit

Claims (2)

A base station of a wireless communication system;
A radio signal received from the base station is converted into an optical signal and output, and a received optical signal is converted into a radio signal and output to the base station.
A receiver that converts the received optical signal into a radio signal, amplifies it, and outputs it from the antenna,
An optical transmission system in which the slave unit is connected to the repeater in a chain form by an optical fiber,
Comprising a maintenance device connected to the relay ,
A delay parameter indicating the inherent delay time inside the device is stored in advance in the relay device and the slave device,
The delay parameter of the repeater is a parameter indicating a delay time until the optical signal is output from the wireless signal input terminal of the repeater,
The delay parameter of the slave unit is a first parameter that is a delay time from when the reference signal of the optical signal is received from the host device to when the optical signal is returned to the host device, and the optical signal received from the host device is lower A second parameter that is a delay time until output to the device, and a third parameter that is a delay time until the optical signal received from the host device is converted into a radio signal and output from the antenna,
At the time of system startup , the time difference between the timing at which the repeater and the slave unit transmit the reference signal to the lower level device and the timing at which the reference signal returned from the lower level device is received is the light in the optical fiber connected to the lower level. Measured as line delay,
The slave unit, the first is the storage, second, reads out the third parameter, and sends to the relay device with the measured optical line delay,
The repeater is an optical time line delay amount optical line delay itself are measured and a plurality of slave unit is measured, the first self-delay parameter and the plurality of slave unit, second, third send a parameter to the maintenance device,
The maintenance device includes a display unit, and an optical line delay amount measured by the repeater or the slave unit, and the first parameter of a slave unit connected to a lower level of the repeater or the slave unit, The difference between the two is calculated, and the half time of the difference is calculated as the transmission delay amount of the optical fiber connected to the lower level of the repeater or the slave unit,
Delay parameters of the repeater, transmission delay amounts of all optical fibers that pass from the repeater to any slave unit that outputs an antenna, and all slave units that pass from the repeater to the any slave unit The time of the sum of the second parameter of the second and the third parameter of the arbitrary slave unit is calculated as a delay time from the radio signal input of the repeater to the antenna output of the arbitrary slave unit,
Optical transmission system and displaying the the transmission delay amount of each optical fiber, and a delay time of the child devices in Table radical 113. A base station of a radio communication system, a radio signal received from the base station, converted into an optical signal and output, and a relay device that converts the received optical signal into a radio signal and outputs the radio signal to the base station A slave unit that converts an optical signal into a radio signal, amplifies it, and outputs it from an antenna, and a maintenance device connected to the repeater, and a plurality of the slave units are connected to the repeater in a chain form by an optical fiber A transmission delay time calculation method in an optical transmission system,
A delay parameter indicating the inherent delay time inside the device is stored in advance in the relay device and the slave device,
Delay parameter of the repeater is a parameter indicating a delay time from the radio signal input of the repeater to the output of the optical signal,
Delay parameter of the slave unit, the lower first and parameters from the reception of the reference signal of the optical signal from the host device is a delay before replying to the host device by the optical signal, the optical signal received from the host apparatus A second parameter that is a delay time until output to the device, and a third parameter that is a delay time until the optical signal received from the host device is converted into a radio signal and output from the antenna,
At system startup, the relay device and the child device, the timing of transmitting a reference signal to the lower apparatus, light at the returned reference signal connected optical fiber a time difference between the reception timing in the lower from the lower device Measured as line delay,
The slave unit reads the stored first, second, and third parameters, and transmits them to the repeater together with the measured optical line delay amount.
The repeater measures the optical line delay amount measured by itself, the optical line delay amount measured by the plurality of slave units, the own delay parameter, and the first, second, and third parameters of the plurality of slave units, To the maintenance device,
The maintenance device obtains a difference between an optical line delay amount measured by the repeater or the slave unit and the first parameter of a slave unit connected to a lower level of the repeater or the slave unit , Half the difference is calculated as the transmission delay amount of the optical fiber connected to the lower level of the repeater or the slave unit,
Delay parameters of the repeater, transmission delay amounts of all optical fibers that pass from the repeater to any slave unit that outputs an antenna, and all slave units that pass from the repeater to the any slave unit wherein the second parameter, to calculate the time of the sum of the third parameter of the arbitrary slave unit, as a delay time from the radio signal input of the repeater to the antenna outputs of the arbitrary handset A transmission delay time calculation method.

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