JP2002077031A - Base station device for point/multi-point subscriber wireless system, and method for interconnecting indoor unit and outdoor unit of the system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base station device for a point/multi-point subscriber wireless system that can quickly and easily interconnects units of a base station device with an economically advantageous configuration independently of unit installation conditions of the base station device without the need for trouble some adjustment and circuit operations at all and to provide a method for interconnecting an indoor unit and an outdoor unit of the system. SOLUTION: The outdoor unit(ODU) 21 of the base station device 2 receives wireless signals sent from subscriber station devices 1a-1n by an antenna 21a and an RF circuit section 21b, uses an electrooptic conversion section 21c to convert an output signal (IF signal) from the RF circuit section 21b into an optical signal, and transmits the optical signal to the indoor unit(IDU) 22 via an optical fiber 23. The indoor unit(IDU) 22 uses a photoelectric conversion section 22d to restore the optical signal on the optical fiber 23 into the IF signal and allows an IF circuit section 22a to restore the IF signal into a base band signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outdoor unit and an indoor unit for receiving radio signals transmitted from a plurality of subscriber stations, restoring the signals into electric signals, and transmitting the signals to station equipment in a subscriber network. The present invention relates to a base station apparatus for a point / multipoint subscriber wireless system.

[0002] The present invention also provides a plurality of subscriber station devices for accommodating various communication lines from the subscriber devices, converting electrical signals from the subscriber devices into radio signals, and transmitting the signals. Connection between indoor unit and outdoor unit of a point / multipoint subscriber wireless system including a base station apparatus for receiving a wireless signal transmitted from a base station, restoring the electrical signal and transmitting the electrical signal to station equipment in a subscriber network About.

[0003]

2. Description of the Related Art A plurality of subscriber station apparatuses for accommodating various communication lines from subscriber apparatuses, converting electric signals from the subscriber apparatuses into radio signals, and transmitting the signals, and transmitting signals from the respective subscriber station apparatuses. FIG. 3 shows a conventional configuration of a point-to-multipoint subscriber wireless system including a base station apparatus that receives a received wireless signal, restores it to an electric signal, and transmits it to station equipment in a subscriber network.

As shown in FIG. 3, this type of point / multipoint subscriber radio system accommodates various communication lines (IEEE 802.3, I.431a, etc.) from a subscriber unit, and receives from the subscriber unit. A plurality of subscriber station devices 01a to 01n for converting an electric signal into a radio signal and transmitting the signal;
The base station device 02 receives radio signals transmitted from the plurality of subscriber station devices 01a to 01n, restores the signals to electric signals, and transmits the electric signals to station equipment in the subscriber network. In addition, from the base station device 02 to the subscriber station devices 01a to 01n.
The same signal flows from the base station device 02 to the plurality of subscriber station devices 01a to 01n in the form of radio signals, and the respective subscriber station devices 01a to 01n extract a signal portion addressed to the own station. Then, the extracted signal is sent to the communication line of the subscriber device accommodating the extracted signal.

In the point-to-multipoint subscriber radio system having such a configuration, the base station apparatus 02 performs radio transmission with a plurality of subscriber station apparatuses 01a to 01n. It is necessary to install a plurality of antennas at positions where wireless transmission conditions are good enough to see through. Therefore, the base station device 02 is connected to the outdoor unit (ODU) 0
3 and an indoor unit (IDU) 04.

The outdoor unit (ODU) 03 is composed of an antenna (antenna) 03a, an RF circuit section 03b, and the like.
The indoor unit (IDU) 04 includes an IF circuit unit 04a, a modem (modem) unit 04b, and a subscriber network interface unit 0.
4c and the like. Outdoor unit (ODU) 0
3 and the indoor unit (IDU) 04 are physically separated from each other, so that the RF of the outdoor unit (ODU) 03
The circuit unit 03b and the IF circuit unit 04a of the indoor unit (IDU) 04 are connected by a signal cable having a length corresponding to the distance (laying distance) between the installation positions of the two units.

Usually, a coaxial cable having the same impedance characteristics is used as this kind of signal cable, but the RF circuit section 03b of the outdoor unit (ODU) 03
And the IF signal transmitted between the IF circuit unit 04a of the indoor unit (IDU) 04 is a high-frequency signal (modulated high-frequency signal) of several tens of MHz to several GHz, and therefore depends on the cable length. The level drops. Therefore, it is necessary to adjust the output level of the IF circuit unit 04a provided in the indoor unit (IDU) 04 in order to keep the transmission level at the input terminal of the antenna 03a provided in the outdoor unit (ODU) 03 at a constant value. is there. Also, as for the reception level, since the input level of the IF circuit section 04a fluctuates depending on the cable length, it is necessary to widen the dynamic range of the IF circuit section 04a accordingly.

If the outdoor unit (ODU) 03 and the indoor unit (IDU) 04 are extremely close, the cable length is short, and the fluctuation of the signal level is within a negligible range. Although it is not necessary to consider it, usually, the outdoor unit (ODU) of the base station device 02
03 and the indoor unit (IDU) 04 will be installed quite far apart.

When the antenna 03a is installed on the roof of a building as a place with good wireless transmission conditions and good visibility, for example, the indoor unit 22 may be installed in various places from the ground floor to the top floor of the building. At this time, the cable length has a width of, for example, several tens of meters to several hundreds of meters.

[0010] The cable loss of the high-frequency signal is, for example, 200 m for a 12D-FB cable and a frequency band of 1.4 G.
In Hz, nearly 40 dB is expected. Therefore, in this case, it is necessary to adjust the transmission level for each installation site of the base station device 02, which is equivalent to the antenna gain. In addition, the reception dynamic range also needs an extra 40 dB.

Further, conventionally, as a measure for satisfying the above conditions, the above cable length is set to a length of a certain unit length, and an excess cable (a coaxial cable that has been excessively laid) is placed on the floor. Since it is wound and stored, a storage space for storing the surplus coaxial cable is required.

Conventionally, as described above, since the RF circuit section 03b of the outdoor unit (ODU) 03 and the IF circuit section 04a of the indoor unit (IDU) 04 are connected by a coaxial cable, In order to keep the transmission level at the input end of the antenna 03a provided in the outdoor unit (ODU) 03 at a constant value, it is necessary to adjust the output level of the IF circuit unit 04a provided in the indoor unit (IDU) 04 Since the input level of the IF circuit section 04a also varies depending on the cable length, the dynamic range of the IF circuit section 04a needs to be widened accordingly. Each site requires cumbersome and complicated circuit adjustments and ingenuity, which requires a lot of time and effort. There was. In addition, there is also a problem that it is necessary to secure a relatively large storage space for storing the coaxial cable that is excessively laid.

[0013]

As described above, in the conventional system configuration of the point-to-multipoint subscriber radio system, the RF circuit section provided in the outdoor unit of the base station apparatus and the indoor unit include the RF circuit section. I provided
Since the connection with the F circuit unit is made by a coaxial cable, the output of the IF circuit unit provided in the indoor unit is maintained in order to keep the transmission level at the input terminal of the antenna provided in the outdoor unit constant. In addition to the need to adjust the level, the input level of the IF circuit also fluctuates depending on the cable length, so that the dynamic range of the IF circuit must be widened accordingly. Each site of the base station equipment requires complicated and complicated circuit adjustments and contrivances, which requires a lot of time and labor, and has a problem that the circuit configuration is complicated and expensive. . In addition, there is a problem that it is necessary to secure a relatively large storage space for storing the coaxial cable that is excessively laid.

The present invention has been made in view of the above circumstances,
A plurality of subscriber station devices for accommodating various communication lines from the subscriber devices, converting electrical signals from the subscriber devices into radio signals and transmitting the radio signals, and receiving radio signals transmitted from the respective subscriber station devices; In a point / multipoint subscriber wireless system composed of a base station device for restoring an electric signal and transmitting the signal to a station facility in a subscriber network, the system is complicated regardless of unit installation conditions of the base station device. The base station device of the point / multipoint subscriber wireless system and the system which has an economically advantageous structure that allows quick and easy connection between units of the base station device without requiring any simple adjustment work and circuit operation. An object is to provide a connection method between an indoor unit and an outdoor unit.

[0015]

SUMMARY OF THE INVENTION The present invention provides a plurality of subscriber station devices for accommodating various communication lines from subscriber devices, converting electric signals from the subscriber devices into radio signals, and transmitting the signals. In a point / multipoint subscriber radio system comprising a base station device which receives a radio signal transmitted from each subscriber station device, restores the radio signal to an electric signal, and transmits it to a station facility in the subscriber network, In connecting the outdoor unit and the indoor unit of the base station apparatus with a cable, an electric-optical conversion unit is provided in each of the units, and an optical fiber is used as a signal cable medium. It is not necessary to adjust the signal level between the units.

That is, the present invention relates to a point between an outdoor unit and an indoor unit, which receives a radio signal transmitted from a plurality of subscriber station devices, restores the signal to an electric signal, and transmits the signal to a station facility in a subscriber network. In the base station apparatus of the multipoint subscriber wireless system, an electric signal-optical signal conversion unit is provided at each transmission end of a transmission line connecting the outdoor unit and the indoor unit, and the outdoor unit and the indoor unit are provided. The unit and the unit are connected by an optical cable.

The present invention also relates to a point comprising an outdoor unit and an indoor unit for receiving radio signals transmitted from a plurality of subscriber station devices, restoring them into electric signals, and transmitting them to station equipment in a subscriber network. In the base station device of the multipoint subscriber radio system, the outdoor unit includes an antenna and a radio signal transmitting / receiving unit for transmitting / receiving a radio signal to / from the plurality of subscriber station devices, and a radio signal transmitting / receiving unit. An electrical signal-to-optical signal conversion unit for converting an electrical signal to an optical signal at an indoor unit side signal transmission end, and a subscriber network for transmitting and receiving signals on a communication line to and from the indoor unit to the indoor unit. An interface unit, a modulation / demodulation circuit unit and an amplification circuit unit for modulating / demodulating a signal transmitted / received between the subscriber network interface unit and a radio signal transmission / reception unit provided in the outdoor unit. An electrical signal-to-optical signal converter for converting an electrical signal to an optical signal at an outdoor unit-side signal transmission end of the amplifier circuit unit, wherein the electrical signal-to-optical signal converter of the outdoor unit and the electrical signal light of the indoor unit are provided. An optical cable is connected to the signal converter, and a modulated high-frequency signal is transmitted between the outdoor unit and the indoor unit via the optical cable.

Further, the present invention provides a plurality of subscriber station devices for accommodating various communication lines from subscriber devices, converting electric signals from the subscriber devices into radio signals, and transmitting the radio signals. A connection between an indoor unit and an outdoor unit of a point / multipoint subscriber wireless system composed of a base station device that receives a wireless signal transmitted from the device, restores the electrical signal, and transmits the electrical signal to the station equipment in the subscriber network. In the method, when connecting the indoor unit and the outdoor unit of the base station apparatus with a signal cable, an electric-optical conversion unit is provided in each unit, and an optical fiber is connected to a signal cable medium between the units. The need for adjusting the signal level between the units depending on the signal cable length is eliminated.

By adopting the configuration of the present invention as described above, regardless of the installation conditions of the outdoor unit of the base station apparatus,
Since there is no need to adjust the transmission level or to make the reception dynamic range width wider than necessary, there is no need for complicated adjustment work and circuit operation, and the economy can be quickly and easily connected between base station units. A point-to-multipoint subscriber wireless system having an advantageous configuration can be provided.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a point-to-multipoint subscriber wireless system according to an embodiment of the present invention.

In the figure, reference numerals 1a to 1n denote various communication lines (IEEE 802.3, I.431a) from the subscriber unit.
Etc.), and converts the electric signal from the subscriber device into a radio signal and transmits the radio signal, and converts the received radio signal to an electric signal level of the subscriber device and transmits the signal to the corresponding destination subscriber device. Is a subscriber station device.

2 receives radio signals transmitted from a plurality of subscriber station devices 01a to 01n, restores the signals to electric signals, and transmits them to station equipment in the subscriber network. Is a base station that transmits a transmission signal from the subscriber stations 01a to 01n by radio signals.

The base station device 2 includes an outdoor unit (OD)
U) 21 and an indoor unit (IDU) 22.

The outdoor unit (ODU) 21 is provided with components such as an antenna 21a, an RF circuit 21b, and an electro-optical converter 21c.

The indoor unit (IDU) 22 is provided with components such as an IF circuit section 22a, a modulation / demodulation section 22b, a subscriber network interface section 22c, and an electro-optical conversion section 22d.

An electro-optical converter 21c is provided at a signal end on the indoor unit (IDU) side of the RF circuit section 21b provided in the outdoor unit (ODU) 21, and the indoor unit (I
An electro-optical converter 22d is provided at the outdoor unit (ODU) side signal end of the IF circuit unit 22a provided in the DU) 22,
An optical fiber 23 connects between an electro-optical converter 21c provided in the outdoor unit (ODU) 21 and an electro-optical converter 22d provided in the indoor unit (IDU) 22.

In the above configuration, the subscriber station devices 1a to 1
n converts electric signals of various communication lines (IEEE802.3, I.431a, etc.) transmitted from the subscriber unit into radio signals of a predetermined frequency and transmits the radio signals from an antenna (antenna).

The outdoor unit (ODU) 2 of the base station device 2
1, an antenna 21a and an RF circuit unit 21b receive radio signals transmitted from the subscriber station devices 1a to 1n, and an output signal (IF signal) of the RF circuit unit 21b is optically converted by an electro-optical conversion unit 21c. After being converted into a signal, the signal is transmitted to an indoor unit (IDU) 22 via an optical fiber 23.

In the indoor unit (IDU) 22, the optical signal received from the outdoor unit (ODU) 21 via the optical fiber 23 is converted back to an IF signal by the electro-optical conversion unit 22d, and the base is transmitted by the IF circuit unit 22a. The signal is returned to the band signal, restored to an electric signal by the modem unit 22b, and returned to the original communication line form, or in a form in which a plurality of communication lines are condensed, in the subscriber network via the subscriber network interface unit 22c. To the station equipment.

The reverse signal flow, which is the reverse of the upstream signal flow, follows the upstream signal flow in the reverse route, and is switched from the subscriber network interface unit 22c to the modem unit 22b to the IF circuit unit. 22a to electro-optical converter 22d
Electro-optical converter 21c to RF circuit 21b to antenna 21
a is transmitted to each of the subscriber station devices 1a to 1n by a radio signal.

Here, the outdoor unit (ODU) 21
And the indoor unit (I)
The optical fiber 233 connected to the electro-optical converter 22d provided in the DU) 22 has an extremely small transmission loss as compared with the coaxial cable, and is at most only about 0.5 dB / km. For this reason, the cable loss is so small that it can be neglected to connect the outdoor unit (ODU) 21 and the indoor unit (IDU) 22 that are at most several hundred meters apart.

FIG. 2 shows an electro-optical converter 21c provided in the outdoor unit (ODU) 21 and an indoor unit (ID).
U) is a block diagram showing an internal configuration of an electro-optical converter 22d provided in 22. Each of the electro-optical converters 21c has the same circuit configuration.

In the indoor unit (IDU) 22, I
The down direction from the F circuit unit 22a is the electric-optical conversion unit 22d.
The IF signal is converted into an optical signal by an electric / optical converter (E / O) inside the optical fiber and sent to the optical fiber 23a. In the outdoor unit (ODU) 21, the optical signal on the optical fiber 23a is converted again into an electric signal (IF signal) by an optical / electrical converter (O / E) in the electro-optical converter 21c, and the RF circuit Part 2
1b.

In the outdoor unit (ODU) 21, an IF signal is converted into an optical signal by an electric / optical converter (E / O) in an electric / optical converter 21 c in the upward direction from the RF circuit section 21 b. Then, it is sent to the optical fiber 23b. In the indoor unit (IDU) 22, the optical signal on the optical fiber 23b is converted into an optical / electrical converter (O /
The signal is again converted into an IF signal at E) and sent to the IF circuit section 22a. That is, the outdoor unit (ODU) 21 and the indoor unit (IDU) 22 are connected by one pair of optical cables.

With the base station configuration using the optical cable of the above-described embodiment, the transmission level adjustment becomes unnecessary and the receiving dynamic range width becomes unnecessarily irrespective of the installation condition of the outdoor unit of the base station apparatus. A configuration that does not need to be widely used can be provided. That is, since the optical fiber has an extremely small cable loss of 0.5 dB / km, the outdoor unit (ODU) 21 and the indoor unit (ID)
U) 22 can be much larger than the building height, and therefore, the building where the indoor unit (IDU) 22 is installed even in a location where a plurality of buildings stand in a forest. However, the outdoor units (ODUs) 21 can be dispersedly arranged in these multiple buildings, and the degree of freedom in installing the outdoor units in consideration of the prospect of wireless transmission increases.

In the above embodiment, the R of the outdoor unit (ODU) 21 is connected via the optical fiber 23b.
Although an IF signal (modulated signal) is transmitted between the F circuit unit 21b and the IF circuit unit 22a of the indoor unit (IDU) 22, the signal is not limited to the signal and may be, for example, an indoor unit (ID).
It is also possible to superimpose and transmit a control signal, a monitoring signal, and the like exchanged between the U) 22 and the outdoor unit (ODU) 21.

[0038]

As described above in detail, according to the present invention, a plurality of subscriber stations accommodating various communication lines from a subscriber unit, converting an electric signal from the subscriber unit into a radio signal and transmitting the radio signal. Point / multipoint subscriber radio system comprising a radio communication apparatus, and a base station apparatus for receiving a radio signal transmitted from each of the subscriber station apparatuses, restoring the electric signal, and transmitting the electric signal to a station equipment in a subscriber network. An economically advantageous configuration that allows quick and easy connection between base station units without depending on the unit installation conditions of the base station unit and without any complicated adjustment work and circuit operation. The base station apparatus of the point / multipoint subscriber wireless system and the connection method between the indoor unit and the outdoor unit of the system can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a point-to-multipoint subscriber wireless system according to an embodiment of the present invention.

FIG. 2 is an exemplary block diagram showing a configuration of a main part in the embodiment.

FIG. 3 is a block diagram showing a configuration of a conventional point / multipoint subscriber wireless system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Subscriber station apparatus 2 ... Base station apparatus 21 ... Outdoor unit (ODU) 22 ... Indoor unit (IDU) 23 ... Optical fiber cable 21a ... Antenna 21b ... RF circuit part 21c ... Electro-optical conversion part 22a ... IF circuit part 22b … Modulator / demodulator 22c… Subscriber network interface 22d… Electro-optical converter

Claims (3)

[Claims] 1. A point-to-multipoint subscription comprising an outdoor unit and an indoor unit for receiving radio signals transmitted from a plurality of subscriber station devices, restoring the signals into electric signals, and transmitting them to station equipment in a subscriber network. In the base station apparatus of the user wireless system, an electric signal-optical signal conversion unit is provided at each transmission end of a transmission path connecting the outdoor unit and the indoor unit, and the transmission unit is connected between the outdoor unit and the indoor unit. A base station apparatus for a point / multipoint subscriber wireless system, wherein the base stations are connected by an optical cable. 2. A point / multipoint subscription comprising an outdoor unit and an indoor unit for receiving radio signals transmitted from a plurality of subscriber station devices, restoring them into electric signals, and transmitting them to station facilities in a subscriber network. In the base station device of the user wireless system, the outdoor unit, an antenna and a radio signal transmitting / receiving unit for transmitting / receiving a radio signal to / from the plurality of subscriber station devices, and an indoor unit-side signal of the radio signal transmitting / receiving unit An electrical signal-to-optical signal conversion unit that converts an electrical signal to an optical signal at a transmission end; and the indoor unit, a subscriber network interface unit that exchanges a signal on a communication line with the station equipment, A modulation / demodulation circuit unit and an amplification circuit unit for modulating / demodulating a signal transmitted / received between the subscriber network interface unit and a radio signal transmission / reception unit provided in the outdoor unit; An electric signal-to-optical signal conversion unit for converting an electric signal to an optical signal at an outdoor unit side signal transmission end of the road unit, wherein the electric signal-to-optical signal conversion unit of the outdoor unit and the electric signal-to-optical signal conversion of the indoor unit A base station apparatus for a point-to-multipoint subscriber radio system, wherein the base station apparatus is connected to an outdoor unit and an indoor unit via the optical cable. . 3. A plurality of subscriber station devices for accommodating various communication lines from the subscriber device, converting an electric signal from the subscriber device into a radio signal, and transmitting the radio signal, and transmitting from each of the subscriber station devices. And a base station apparatus for receiving the restored radio signal, restoring it to an electric signal, and transmitting the restored electric signal to the station equipment in the subscriber network, wherein the base station apparatus is an indoor unit. It is configured to be divided into outdoor units, and in connecting each unit with a signal cable, an electric-optical conversion unit is provided in each unit,
By using an optical fiber as a signal cable medium between the units, it is not necessary to adjust the signal level between the units depending on the signal cable length. Connection method between indoor unit and outdoor unit.