JP2003309578A - Radio access system in subscriber system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily avoid a communication failure such as a transmission line failure due to rainfall attenuation, snowfall and obstructions in a radio access system in a subscriber system using microwaves and quasi-millimeter waves. <P>SOLUTION: In the radio access system using a communication channel connected in a ring shape among radio stations, when the communication failure is occurred between a radio station B and a radio station C, transmitters 2b2, 2a2 to become relay stations are placed at a position of a radio station F which is not adjacent to the radio stations B, C. Accordingly, the radio station B communicates by configuring the communication channel shaped like a ring through communication with the radio station C via the relay stations. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a subscriber wireless access system for wireless communication using a directional antenna for microwaves or quasi-millimeter waves.

[0002]

2. Description of the Related Art In subscriber wireless communication using microwaves or quasi-millimeter waves, PTPs (Point to point) facing each other are used.
In the case of using wireless communication of Point connection (hereinafter referred to as a wireless link), in order to extend the communication distance to widen the coverage area of the wireless service of the subscriber system, and to prevent a wireless propagation path failure and equipment failure, The radio link is connected to the subordinate in order to avoid the obstacle of the communication section. Then, there has been proposed a subscriber wireless access system in which the start and end of the chained wireless link are connected to each other and the wireless communication path is formed into a loop ring connection.

Hereinafter, a wireless communication path means an entire communication path composed of a number of wireless links, and a wireless propagation path means a space where radio waves of opposite wireless transceivers forming a wireless link propagate. I mean.

FIG. 7 shows a radio access system 1 that performs loopback to avoid a communication failure on a ring-connected radio communication path.
It is explanatory drawing of a form.

In FIG. 7, the wireless stations are composed of six stations, and are numbered A1, B1, C1, D1, E1, and F1, respectively. Each of the wireless stations (A1 to F1) includes an ATM node 3, a transceiver 2a that transmits signals between adjacent wireless stations, and a transceiver 2b.

The ATM node 3 connects and accommodates a subscriber's communication terminal, performs ATM (asynchronous) multiplexing with a signal transmitted between ATM nodes 3 of adjacent radio stations forming a ring, and simultaneously separates a signal addressed to itself. And take it out. When the line is normal, for example, in the clockwise direction of FIG.
1-D1-E1-F1-A1 ring transmission is performed.

Here, when a communication failure occurs between the wireless station B1 and the wireless station C1, the signals are returned by the wireless station B1 and the wireless station C1 so that, for example, the wireless stations A1-B1-A1-
By performing loopback via the route of F1-E1-D1-C1-D1-E1-F1-A1, it is possible to avoid communication interruption due to communication failure. However, in the ring connection, although the failure can be avoided by the loopback described above, the node device isolated when the communication failure occurs at two or more places due to complication of multiple communication control such as change of transmission order and round trip of the same signal. There is a problem that occurs.

On the other hand, when a communication failure occurs in a wireless link, a method has been proposed in which the wireless link is duplicated so that it does not loop back (loopback) and the node isolation described above is prevented. The method will be described with reference to FIG.

FIG. 8 is a block diagram of a configuration in which the wireless links of the portions corresponding to the wireless stations B1 and C1 of the wireless access system having the configuration of FIG. 7 are duplicated. The wireless station B2 is the wireless station B1.
The wireless station C2 corresponds to the wireless station C1. Radio station B2 is transceivers 2a1 and 2a2, and radio station C2 is transceiver 2b1.
And 2b2.

In FIG. 8, a radio station B2 and a radio station C2 are provided with a main line radio link using the transceivers 2a1 and 2b1 and a backup radio link using the transceivers 2a2 and 2b2 installed in parallel and duplexed. ing.

Conventionally, when the wireless link is duplicated,
Install a backup wireless link transceiver 2a2 in the same building where the main line transceiver 2a1 is installed.
It was heavy.

However, if two sets of wireless links are installed in parallel in the same building, these two sets of wireless links are close to each other, and therefore, the radio propagation path obstacle due to rain attenuation or snowfall, and the antenna functioning as a building cleaning machine. In the case of an obstacle in which an obstacle appears on a wireless propagation path forming a wireless link, such as when it is shielded, both the main line and the backup line are affected in the same way, so neither of them can avoid the obstacle.

Further, in the case of duplexing in parallel radio propagation paths in the vicinity, as shown by the dotted line in FIG. 8, the transmission wave of the radio link of the backup line is mixed with the radio link for the main line. On the contrary, there is a problem that it is necessary to avoid radio wave interference in which the transmission wave of the radio link for the main line is mixed with the radio link of the backup line.

On the other hand, there is a method of installing a wireless relay station for backup in another building in order to avoid the above-mentioned communication failure, but the construction cost and the maintenance and operation cost for installing the wireless relay station in another building are There was a problem such as a new one.

[0015]

Conventionally, in a subscriber radio access system, a method of looping back a ring connection of radio stations as described above when a communication failure occurs in radio communication,
Or, the backup line was installed in parallel with the main line, and the wireless link was duplicated, aiming to avoid it. However, in this method, communication control at the time of loopback is complicated, or duplication in parallel radio propagation paths in parallel is not effective enough for rain attenuation, snowfall, and obstacle countermeasures, and There was a problem such as interference between the main line and the backup line.

The present invention provides a subscriber radio access system capable of easily avoiding rain attenuation and snowfall of a subscriber radio access system using microwaves or quasi-millimeter waves and communication obstacles in a radio propagation path due to obstacles. The purpose is to provide.

[0017]

In order to achieve the above object, the subscriber radio access system of the present invention is an inter-radio station using directional antennas in at least five microwave or quasi-millimeter wave bands. In the subscriber wireless access system that performs the communication of 1) by transmitting a main signal to a wireless communication path connected in a loop, when a communication failure occurs between the first wireless station and the second wireless station, First radio station and second
A relay station is provided at a position of a third wireless station that is not adjacent to the second wireless station, and the main signal from the first wireless station is communicated with the second wireless station via the relay station, thereby forming a loop. It is characterized in that a wireless communication path connected in a line is configured to perform communication.

Further, in the subscriber radio access system of the present invention, communication between radio stations using directional antennas of microwaves or quasi-millimeter waves at at least four places is connected to a radio communication path connected in a loop. In a subscriber radio access system that transmits a main signal, if a communication failure occurs between the first radio station and the second radio station, the main signal from the first radio station is transmitted to the third radio station. To the wireless station of
Wireless station transmits the main signal to the second wireless station directly or via another wireless station, the second wireless station transmits the main signal to a fourth wireless station, and the fourth wireless station transmits the main signal to the fourth wireless station. The wireless station of (1) transmits the main signal to the first wireless station directly or via another wireless station, thereby forming a loop-shaped wireless communication path by the Tatsukigae connection to perform communication. To do.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. 1 and 2 are system configuration examples of an embodiment of a subscriber wireless access system according to the present invention. FIG. 3 is a detailed block diagram of the basic configuration of a wireless station used in the subscriber wireless access system of FIG. 4, 5 and 6 show that when a failure occurs in the wireless communication path,
To prevent communication failures in the subscriber wireless access system,
It is a block diagram explaining the composition of the radio station which has a transceiver for backup.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
2 shows an embodiment of the present invention. In the first embodiment, there are six wireless stations that make up the subscriber wireless access system, and numbers A to F are assigned to the wireless stations, respectively. It is installed on the rooftop of a building or on a steel tower at a position in the interval and direction where an appropriate reception intensity can be obtained.

When no failure occurs in the wireless communication path, for example, a message is sequentially transmitted from the wireless station A to the wireless station F, and a ring-shaped transmission path is formed to make a round from the wireless station F to the wireless station A again. is doing.

Each of the wireless stations A to F has an ATM node 3
And a transceiver 2a that transmits a signal between adjacent wireless stations,
As shown in FIG. 4 for the wireless station B, FIG. 5 for the wireless station C, and FIG. 6 for the wireless station F, the transceivers 2a and 2b are respectively 2a1, 2a2 or 2b1, It is duplexed like 2b2, and has a configuration prepared for communication failure.

In the wireless station A, a subscriber's communication terminal (not shown) is connected to the ATM node 3 and a message is output from the communication terminal. Also, the ATM node 3 of the wireless station A
The ATM transmits the information of the wireless station B received by the transceiver 2b and the message output from the communication terminal connected to itself to the ATM.
Multiplexing (asynchronous multiplexing) is performed, and ATM transmission is performed from the transceiver 2a to the transceiver 2b of the wireless station B.

The ATM node 3 also takes out a message having an address addressed to itself and outputs it to a communication terminal (not shown) in the radio station. This multiplexed and transmitted message is called a main signal, and the subscriber's message input from the ATM node 3 of the wireless station A is multiplexed with the main signal from the immediately preceding wireless station F, which is transmitted from the transceiver 2a. It is sent to the next wireless station B.

The message transmission method in the other wireless stations B to F is similar to that in the case of the wireless station A, and the process of sequentially transmitting the message to its own address is performed.

FIG. 3 is a detailed block diagram of the basic configuration of the wireless stations AF, and the basic operation of the wireless link in the present invention will be described with reference to FIG. The transceivers 2a and 2b are composed of a set of a receiver RX and a transmitter TX, an antenna ANT, and a radio monitoring switching circuit CX.

The radio monitoring switching circuit CX measures the communication quality such as the radio wave reception level of the receiver RX and the error rate of the received signal. If the communication quality of the radio wave received by the receiver RX of the transceiver 2b is at a predetermined level, the received main signal is sent to the ATM node 3 and the main signal is demultiplexed in the ATM node 3. Then, the signal is transmitted from the transmitter TX of the transceiver 2a by the antenna ANT. Further, the main signal received by the receiver RX of the transceiver 2a is similarly output from the antenna ANT via the transmitter TX of the transceiver 2b.

When the radio monitoring switching circuit CX determines that the communication quality is poor, the respective transceivers 2a and 2b are disconnected from the ATM node 3,
Predetermined switching is performed for each wireless station according to the setting of station placement design.

That is, in FIG. 1, the main signal is normally transmitted through the ring path of the wireless stations A-B-C-D-D-E-F-A, but the wireless link between the wireless stations B and C is used. When a failure occurs, the transmission between the wireless station B and the wireless station C is relayed by the wireless link by the transceivers 2a2 and 2b2 placed in the wireless station F, and the wireless stations A-B-F-C-D-E- It is transmitted on the F-A ring path.

FIG. 4 is a detailed block diagram of the configuration corresponding to the wireless station F, FIG. 5 is a detailed block diagram of the wireless station C, and FIG. 6 is a detailed block diagram of the wireless station B.

The individual configuration shown in each of these figures is shown in FIG.
The configuration is the same as that included in. Backup communication in the wireless stations B, C and F when a failure occurs between the wireless stations B and C will be described with reference to FIGS. 4 to 6.

In the radio station B shown in FIG. 6, when the radio monitoring switching circuit CX detects a decrease in the reception level of the main signal in the transceiver 2a1 operating before the occurrence of the fault, it sends an alarm to the ATM node 3. The ATM node 3 switches from the transceiver 2a1 to the backup transceiver 2a2, and communicates with the transceiver 2b2 of the wireless station F using the backup wireless link.

In the radio station C shown in FIG. 5, when the radio monitoring switching circuit CX detects a decrease in the reception level of the main signal in the transceiver 2b1 that was operating before the occurrence of the fault, it sends an alarm to the ATM node 3. The ATM node 3 switches from the transceiver 2b1 to the backup transceiver 2b2 and communicates with the transceiver 2a2 of the radio station F using the backup radio link.

This switching information is transmitted to the radio station C or the radio station B.
Is transmitted from the ATM node 3 to the wireless station F via a transmission path on the wireless ring with no communication failure.

In the radio station F shown in FIG. 4, the transceivers 2b2 and 2a2 connected to the above-mentioned radio stations B and C are set to the operating state and the signals are relayed. At this time, the ATM node 3 of the wireless station C only detects that it is wirelessly relayed by the switching information, and the main signal flowing through the wireless stations B and C does not pass through the ATM node 3.

That is, as shown in FIG. 1, in the communication between the radio station F-E and the radio station F-A of the main line, the transceivers 2b1 and 2a1 of the radio station F are used to communicate between the ATM node and the main signal. I / O continues.

In the first embodiment of the present invention, in order to secure the backup wireless link, the relay transceiver 2 is used.
Although a2 and 2b2 are newly installed in the wireless station F, since the wireless station F utilizes the building already secured, compared to the case where an independent relay station is installed, that is, when a new building is rented and installed. However, the cost problem is reduced. Further, since the duplicated route is different between the main line and the backup line, no interference problem occurs.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention. FIG. 2 shows a failure countermeasure method in which the order of ring-shaped transmission paths is changed. In this case, for example, a ring connection is made in which one round is made in the route of the wireless stations A-B-E-D-C-F-A, and the flow of the main signal when the communication failure occurs between the wireless stations B-C is as shown in FIG. 2 is indicated by a dotted line.

That is, in the case where a relay station at one place interferes with a building in the middle and a communication path (wireless propagation path) cannot be secured as in the first embodiment, a communication path in the shape of a cross is secured.

At this time, the same radio link is used between the radio stations E-D-C as usual, but the direction in which the main signal flows is reversed. Further, in the configuration of FIG. 2, the number of wireless stations located in the wireless stations A and D may be 0 to n (n is an integer).

In this case, FIG. 5 corresponds to the configuration of the wireless station C and the wireless station E, and FIG. 6 corresponds to the wireless station B and the wireless station F. Since those operations are easily understood from the first embodiment, the description is omitted here.

In the second embodiment, when a failure occurs,
Some wireless stations send and receive signals in which the direction of the main signal is reversed, but the round trip on the communication path of the main signal and the decrease in transmission capacity do not occur, the device cost is reduced, and the redundant configuration that facilitates system management, Measures against failures can be realized.

A propagation obstacle in radio communication using microwaves or quasi-millimeter waves is often caused by rain attenuation such as heavy rainfall. Since such rain attenuation is a local phenomenon, the propagation direction of radio waves is concentrated. Communication failures can be avoided by changing to a direction where heavy rain does not occur. Therefore, in the present invention, when the above-mentioned communication failure occurs in the wireless communication path connecting the wireless stations in a ring shape, the relay station is installed in the building in which another wireless station already forming the wireless ring is installed. It is provided and communicates with the relay station by changing the communication direction of the wireless station with the propagation failure and the direction of radio wave propagation, or by changing the order of the wireless communication path and changing the propagation direction Can be avoided.

[0044]

According to the subscriber radio access system of the present invention, which uses a radio communication path in which radio stations are connected in a ring by a microwave or quasi-millimeter wave radio link, a communication failure can be easily avoided. can do.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a wireless access system of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the wireless access system of the present invention.

FIG. 3 is a detailed block diagram of the wireless station shown in FIGS. 1 and 2.

FIG. 4 is a detailed block diagram of the wireless station F shown in FIG.

5 is a detailed block diagram of the wireless station C shown in FIGS. 1 and 2 and the wireless station E shown in FIG.

FIG. 6 is a detailed block diagram of the wireless station B shown in FIGS. 1 and 2 and the wireless station F shown in FIG.

FIG. 7 is a block diagram showing the configuration of a conventional wireless access system.

FIG. 8 is a block diagram of a configuration in which a wireless link in a conventional wireless access system is duplicated on parallel wireless propagation paths.

[Explanation of symbols]

1 wireless station 2, 2a, 2b, 2a1, 2b1, 2a2, 2b2 transceiver 3 ATM node CX wireless monitoring switching circuit TX transmitter RX receiver ANT antenna

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K031 AA08 CB12 DA17 DA20 EA11                       EB05 EB08                 5K033 AA06 CB01 DA17 EA02 EA04                       EA06 EB06 EB07                 5K067 AA01 EE02 EE06 EE10 JJ71                       KK02 KK11                 5K072 AA22 BB27 CC31 DD16 DD17                       EE04 EE36 GG02 GG26

Claims (2)

[Claims] 1. Communication between wireless stations using directional antennas in at least five microwave or quasi-millimeter wave bands,
In a subscriber wireless access system that transmits a main signal to a wireless communication path connected in a loop, when a communication failure occurs between a first wireless station and a second wireless station, the first wireless A relay station at a position of a third wireless station that is not adjacent to the station and the second wireless station, and communicates the main signal from the first wireless station with the second wireless station via the relay station. By doing so, a wireless access system for subscribers is characterized in that a wireless communication path connected in a loop is configured to perform communication. 2. A subscriber radio system for performing communication between radio stations using directional antennas for microwaves or quasi-millimeter waves at at least four locations by transmitting a main signal to a radio communication path connected in a loop. In the access system, when a communication failure occurs between the first wireless station and the second wireless station, the first
Transmitting the main signal from the wireless station to the third wireless station, the third wireless station transmitting the main signal directly or via another wireless station to the second wireless station, Two radio stations send the main signal to a fourth radio station, and the fourth radio station sends the main signal directly or via another radio station to the first radio station. , A subscriber-based wireless access system, characterized in that a loop-shaped wireless communication path is constructed by a takuseki connection to perform communication.