WO2001017138A1

WO2001017138A1 - Wireless communication system

Info

Publication number: WO2001017138A1
Application number: PCT/JP1999/004681
Authority: WO
Inventors: Yoshinori Uchida
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 1999-08-30
Filing date: 1999-08-30
Publication date: 2001-03-08

Abstract

Wireless communications are carried out over wireless radio channels and wireless optical channels having a common layer configuration in time base to the wireless radio channels.

Description

Description Wireless communication system Technical field

The present invention uses a time division multiple access (TDMA) system, a code division multiplex access · time division bidirectional (CDMA / TDD) system or a time division CDMA (Time Division CDMA) system. The present invention relates to a wireless communication system in which a wireless base station and a subscriber station (for example, a fixed wireless station, a semi-fixed wireless station, a mobile station, a mobile wireless station, and the like) wirelessly communicate using a radio wave radio line and an optical radio line. Background art

In a conventional wireless communication system, for example, a mobile station such as a mobile in-vehicle communication device or a mobile portable communication device and a base station separately connect a radio wave radio line and an optical radio line, and use each radio line to perform radio communication. Communication is taking place.

However, wireless communication using radio wave radio links and radio communication using optical radio links transmit irrelevant information independently, and do not complement wireless communication.

Therefore, since the radio wave radio line and the optical radio line do not have a relationship such as frame synchronization, for example, a radio line having an excellent line condition is selectively used to execute radio communication. Is impossible.

As described above, Japanese Unexamined Patent Publication No. Hei 7-264098 and Japanese Utility Model Laid-open Publication No. Hei 6-77350 separately connect a radio wave radio line and an optical radio line separately, as described above. Techniques for executing wireless communication have been disclosed. Since the conventional wireless communication system is configured as described above, irrelevant information can be transmitted independently using the radio radio line and the optical radio line. There were issues such as the inability to share and wirelessly complement each other.

The present invention has been made in order to solve the above-described problems, and an object of the present invention is to obtain a wireless communication system that can complement a wireless communication by sharing a radio wave radio line and an optical radio line. I do. Disclosure of the invention

A wireless communication system according to the present invention executes wireless communication by connecting an optical wireless line having a common layer structure on the time axis to the wireless wireless line in addition to the wireless wireless line.

As a result, there is an effect that the wireless communication can be mutually complemented by sharing the radio wave radio line and the optical radio line.

A wireless communication system according to the present invention is configured to perform synchronization between a radio wave radio line and an optical radio line in time slot units, frame units, multiframe units, or super multiframe units.

This has the effect that wireless communication can complement each other.

In a wireless communication system according to the present invention, a TDMA signal and a time-division CDMA signal are arbitrarily arranged in a time slot train composed of a radio wave radio line and an optical radio line.

This has the effect that the transmission capacity and transmission speed can be matched to the user's requirements.

The wireless communication system according to the present invention provides an It is designed to connect line circuits.

As a result, a radio wave radio line having a low possibility of disconnection compared to an optical radio line is preferentially connected, so that there is an effect that execution of radio communication can be secured.

In a wireless communication system according to the present invention, when wireless communication is terminated, an optical wireless line is disconnected and then a radio wave wireless line is disconnected.

As a result, the priority is given to the connection of the radio wave line, which is less likely to be disconnected than the optical wireless line, so that the execution of the wireless communication can be ensured until the wireless communication is finally completed. effective.

In a wireless communication system according to the present invention, when disconnection of an optical wireless line is detected during execution of wireless communication, reconnection of the optical wireless line is attempted.

This has the effect that the optical wireless line can be reconnected even if the line is temporarily disconnected.

In the wireless communication system according to the present invention, when setting a break position between an uplink and a downlink in a radio wave radio line and a break position between an uplink and a downlink in an optical radio line, setting to a different time position within a frame is performed. Is allowed.

This has the effect of improving the degree of freedom when setting the transmission capacity and transmission speed.

In the radio communication system according to the present invention, the radio wave radio line and the optical radio line have a common layer structure on the time axis and have mutually different slot structures.

This has the effect of being able to accommodate users who need high-speed transmission.

In the wireless communication system according to the present invention, a plurality of time slots are It is designed to be used as a composite time slot.

This has the effect that any transmission rate can be assigned to the user.

A wireless communication system according to the present invention combines a plurality of continuous time slots on a time axis.

This has the effect of dramatically increasing the transmission speed.

A wireless communication system according to the present invention detects a direction in which a base station exists, and sets a direction of an optical antenna to a direction in which a base station exists.

This has the effect of improving the communication environment of the optical wireless link.

A wireless communication system according to the present invention receives information indicating a direction in which a base station exists from the base station, and sets the direction of the optical antenna to the direction in which the base station exists.

In a wireless communication system according to the present invention, a subscriber station measures its own location and detects a direction in which a base station exists.

This has the effect that the direction of the optical antenna can be set to the direction where the base station exists.

The wireless communication system according to the present invention measures the time difference between radio waves arriving from a plurality of base stations to measure its own location, thereby detecting the direction in which the base station exists. There are effects that can be. The wireless communication system according to the present invention measures its own location using a GPS receiver.

This has the effect of being able to easily measure its own location. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a configuration diagram showing a wireless communication system according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory diagram showing a configuration example of a time slot for PCS and cellular by TDA and time division CDMA.

FIG. 3 is a configuration diagram showing the inside of the base station.

FIG. 4 is a configuration diagram showing the inside of the subscriber station.

FIG. 5 is a flowchart showing a processing content of the wireless communication system according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram showing another example of the spectrum configuration of the optical / radio wave shared communication system.

FIG. 7 is an explanatory diagram showing still another example of the spectrum configuration of the optical / radiowave wireless communication system.

Fig. 8 shows that the control channel of the optical wireless spectrum band is set to "low-speed multi-channel optical wireless TD-CDMA slot # 82-0A" and the control channel of the radio wireless spectrum band is set to "low speed." FIG. 10 is an explanatory diagram showing an example of installation in a multi-channel TD-CDMA slot # 81-1A ”.

FIG. 9 is a flowchart showing the processing content of the wireless communication system according to Embodiment 4 of the present invention.

FIG. 10 is a flowchart showing a recovery procedure when the optical wireless line is disconnected while the radio wave wireless line and the optical wireless line are shared. FIG. 11 is a block diagram for explaining position measurement of a subscriber station.

FIG. 12 is a block diagram showing the inside of the subscriber station.

FIG. 13 is a flow chart showing the directivity pointing process of the optical antenna. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Embodiment 1.

FIG. 1 is a configuration diagram showing a wireless communication system according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes a public network (PS TN: Pubic Switching Telephone Network); In addition to the normal communication mode, it has a function to communicate in the asynchronous transfer mode (ATM). Reference numeral 2 denotes a mobile switching center (MSC: Mobi1eSwitchhingCentre) which is connected to the PSTN1 by wire or wirelessly and controls the base stations 3 and 6.

3, 6 are base stations (BS: Base Station) installed at a higher position than the subscriber station 9, 4, 7 are radio wave transmitting / receiving antennas of the base stations 3, 6, and 5 and 8 are base stations 3, 6, The optical wireless transmission / reception antenna 9 is a subscriber station (MS: Mobile Station) that performs wireless communication by connecting the base stations 3 and 6 to the radio and optical wireless lines. However, here, mobile stations, mobile stations, fixed stations, semi-fixed stations, etc. are collectively referred to as subscriber stations.

Numeral 10 denotes a radio transmitting / receiving antenna of the subscriber station 9 and 11 denotes an optical radio transmitting / receiving antenna of the subscriber station 9.

The subscriber station 9 and the base stations 3 and 6 use a digital modulation scheme. Signals are exchanged and wirelessly connected using the following communication method. • Frequency division multiplexing access · Time-division bidirectional communication (FD 4AZT DD (Time D ivision Du 1 e ¾ '^;

• Code division multiple access • Time division bi-directional communication (CodeDiVisMuiltipleAAccessZTimeDiviseion

Dup1ex: CDMA / TDD) method

-Multi-carrier temporary division multiple access · Frequency division two-way communication (Multi — carri ers Tiem e Div i sioni Mul t i p i e Ac c e s s / Freq u en c cy D iv i s io n Du p 1ex: TDMA / FDD)

Ό ΌΜΑ / Ύ Ό D method

• Time division CDMA / ⁷ FDD system

-Time division C DMA / TD D method

Regarding these wireless communication systems, we have already filed patents US Pat. No. 5,805,581 (Japanese Patent Application Laid-Open No. 8-130706), PC TZ JP97 Z0290 and Although described in detail in PC TZ JP97 / 0334492, a wireless communication system in which a base station and a subscriber station have a function of sharing a radio radio line and an optical radio line is described above. Since it is not mentioned in the patent application, it will be described in detail below.

Fig. 2 shows an example of the configuration of a PCS (Persona 1 Communication System) using TDMA and time-division CDMA, and animated slot for cellular 1, and in particular, the radio radio spectrum and the optical radio spectrum. This is an example of a configuration in the case of using a turtle at the same time.

In FIG. 2, # 2 1 — 0 A to 5 A are downlinks (Down-Link) of a time-division CDMA time slot for low-speed data transmission in the first and second frames, and # 2 1 — OB to IB are the keys in the first frame. It is a link (Up-Link).

# 2 2 — 1 Α to 5 Α, # 2 2 — 0 B are the TDMA time slots for the PCS low-speed overnight transmission in the first and second frames.

# 2 3 — 0 A to 4 A, # 2 3 — IB is the TDMA time slot for PCS medium-speed data transmission in the first and second frames, and # 24 — OA to 5 A, # 24 _0B to 1B are TDMA timeslots for transmitting cellular / medium speed / voice information in the first and second frames.

# 2 5 — 1 Α to 5 Α, # 2 5 — 0 B is the TDMA time slot for PCS high-speed data transmission in the first and second frames, and is # 26-0 A to 4 A, # 2 6 — IB is the TD—C DMA time slot for cellular medium-speed data transmission in the first and second frames.

# 2 7 — 0 A to 5 A, # 2 7 — 0 B to LB are time division C DMA time slots for PCS ultra-high-speed data communication in the first and second frames in the optical wireless spectrum band. It is.

FIG. 2 shows Up-Link and Down_Link of TDDT (Division Duplex), where Up-Link is R 1 beside the time axis. _B ~ R 1 ₁ are timeslots a Bok being represented by _B, D own - L ink's horizontal time axis T 1. _{_A} ~ T 1 ₅ _A and T 2. A timeslot being represented by _{_A} ~ T 2 ₃ _A.

Time slot R 1 of Up-Link. And _{_{B ~R 1 1 B, D own}} - timeslot T 1 of the L ink. And the _{_A} ~ T 1 ₅ _A Ri your constitute one frame, timeslot Ding 2. ^ ~ Ding 2 ₃ is an evening Imusu lots belonging to the next frame. That is, FIG. 2 represents one frame and one half frame.

Fig. 2 clearly shows one feature of this system. Time slot in the radio radio spectrum band. Time slot in the optical radio spectrum band. In addition to the time frame and the time frame, the time relationship of the time slot is also consistent. By this means, the radio wave radio link and the optical radio link are synchronized. Although not shown in FIG. 2, the radio radio link and the optical radio link may be synchronized in multiframe units. That is, a layer structure that divides a time slot, a frame, a multi-frame, a super-multi-frame, or the like as one unit may be configured as a method of dividing in the time axis direction.

FIG. 3 is a configuration diagram showing the inside of the base station 3 (the same applies to the inside of the base station 6). In the figure, reference numeral 21 denotes a radio transceiver for performing radio communication with the subscriber station 9 using a radio radio line; 2 2 is an optical transceiver that wirelessly communicates with the subscriber station 9 using an optical wireless line, 23 is a spread that generates a spreading code when the radio transceiver 21 or the optical transceiver 22 transmits and receives CDMA signals. When the received signal of the radio transceiver 21 or the optical transceiver 22 is a CDMA signal, the code generator 24 multiplies the received signal by a spreading code (hereinafter referred to as despreading operation) to obtain a desired signal. Frames and channels that extract information and output it to network connector 25, and if the received signal is a TDMA signal, do not perform despreading and output the information extracted from the time slot to network connector 25 as it is. It is a former. When information is transmitted from the network connector 25, the frame / channel former 24 executes the reverse operation to transmit the transmission signal to the radio transceiver 21 or the optical transceiver 22. Output to

Reference numeral 25 denotes a network connector for transmitting / receiving information to / from the mobile switching center 2, and reference numeral 26 denotes processing of inter-station control information such as a subscriber number and a spreading code to connect the subscriber station 9 to the public network 1. The control information processor 27 sets the frame structure to be transmitted by the base station (see Fig. 2) and performs processing such as selecting TDMA or time division CDMA (TD-CDMA) according to the transmission capacity. Base station control processor. FIG. 4 is a block diagram showing the inside of the subscriber station 9. In the figure, 31 is a radio transceiver for radio communication with the base stations 3 and 6 using radio radio channels, and 32 is an optical radio channel. An optical transceiver that wirelessly communicates with the base stations 3 and 6 by radio.33 is a spreading code generator that generates a spreading code when the radio transceiver 31 or the optical transceiver 32 transmits and receives a CDMA signal. Is a frame / channel former having the same function as the frame / channel former 24 of the base stations 3 and 6, and 35 is a display for displaying information extracted by the frame / channel former 34 and the like. Subscribers can extract necessary information by voice and images. Further, information to be transmitted to the public network 11 can be input using the display 35.

Reference numeral 36 denotes a control information processor for controlling the frame channel generator 34 and the display 35. Reference numeral 37 designates a frame structure to be transmitted by the subscriber station (see FIG. 2), and according to the transmission capacity. It is a subscriber station control processor that performs processing such as selecting TDMA or time division C DMA (TD-C DMA).

Next, a schematic operation when the base station 3 and the subscriber station 9 execute wireless communication will be described (detailed operation will be described later).

First, when the base station 3 and the subscriber station 9 perform wireless communication, for example, an operation of setting up a radio wave radio circuit between the base station 3 and the subscriber station 9 in response to a call request from the subscriber station 9 And wirelessly connect the two (step ST 1).

In this state, a line in the radio wave spectrum band of FIG. 2 is selected.

However, confirm the completion of the wireless connection (step ST 2), and if the wireless connection fails, perform the setting operation of the radio wave radio line again. Next, when the connection of the radio wave radio line is successful, the operation of setting up the optical radio line between the base station 3 and the subscriber station 9 is started while the connection of the radio wave radio line is continued, and the two are optically connected (step ST 3).

In this state, a line in the optical radio spectrum band is selected in addition to the line in the radio radio spectrum band in FIG.

However, the completion of the optical connection is confirmed (step ST4), and if the optical connection fails, the setting operation of the optical wireless line is executed again.

Next, when the connection of the optical wireless line succeeds, the sharing of the radio wireless line and the optical wireless line is started. For example, according to the transmission capacity and the transmission speed, or the use environment of the line (transmission error occurrence status). Then, a convenient wireless line is selected and wireless communication is performed (step ST5).

Then, when terminating the wireless communication, the optical wireless line is disconnected first, and then the radio wave wireless line is disconnected to complete the wireless communication (step ST 6). To start sharing, first connect the wireless radio line, then connect the optical wireless line.To end sharing of the wireless radio line and the optical wireless line, first disconnect the optical wireless line, then disconnect the wireless radio line. The line is disconnected, for the following reasons. In optical wireless lines, if the direction of the subscriber station changes due to the straightness of light, line disconnection is highly likely to occur. Therefore, if a situation where only optical wireless lines are connected is created, wireless communication will not be performed. This is because the possibility of becoming possible is increased.

In areas where optical wireless lines can be connected, radio wave wireless lines are considered to be always connectable.

As is clear from the above, according to the first embodiment, in addition to the radio wave radio line, the radio radio line and the optical radio line having a common layer structure on the time axis are connected to execute radio communication. So that the radio It has the effect of sharing wireless and optical wireless lines and complementing wireless communication with each other.

That is, since the radio wave radio line and the optical radio line have the same layer structure on the time axis, communication using radio waves and communication using light can be handled with the same structure except for the physical properties of radio waves and light. Therefore, there is an effect that a convenient wireless communication line can be freely selected according to the communication environment, and the communication path can be freely switched as necessary.

Although not mentioned in the above description of FIG. 2, in FIG. 2, a multicarrier system using a plurality of carriers is realized in the radio wave spectrum area.

Although not shown in the figure, an optical multi-carrier system using a plurality of wavelengths can be realized even in the optical wireless spectrum region.

Therefore, it is possible to realize a shared multi-line system for radio wave radio lines and optical radio lines. In this case, it is possible to realize a function of coexisting the TDMA signal and the time-division CDMA signal in any commonly configured time slot in the radio wave radio line and the optical radio line.

Although not shown in the figure, a function of distributing information of different transmission speeds to different time slots by changing the chip rate of the time division CDMA of each time slot can also be realized. Extending this idea, the TDMA signal and the time-division CDMA signal can be arranged arbitrarily in the time slot sequence on the time axis. That is, in the optical wireless band and the radio wave wireless band, a function of coexisting a plurality of TDMA signals and a plurality of time-division CDMA signals in the time slot in the time axis direction can be realized. Embodiment 2

Fig. 6 shows another example of the spectrum configuration of the optical wireless / radio wireless shared communication system. FIG.

Unlike the first embodiment, the TDMA signal slot (# 61-1A) is included in the time series of ultra-high-speed optical wireless time division CDMA (TD-CDMA) in the optical wireless spectrum region.

In this time slot, the transmission channel is only for one user, but the highest transmission rate can be realized.

In addition, one frame length includes a radio wave radio link and an optical radio link. In FIG. 6, the break position between the Up Link and the Down Link in the radio radio link and the U The position of the break between p-ink and down ink is different.

That is, while the break position in the radio wave radio line is 3 time slots, the break position in the optical radio line is 2 time slots. In the radio spectrum area, the TDMA signal between different frequency channels or the break between the Uplink and Downlink of the TD-CDMA signal is different from each other in one frame. In such a case, the transmitting side radio wave of the base station may suppress the received signals in different time slots.

However, even when the break between the Up-link and the Down-link is at a different time slot in one frame, as in the second embodiment, one is radio wave radio communication and the other is radio wave communication. If is an optical wireless communication, the transmission schemes are completely different, so that the effects on each other can be reduced.

In addition, if at least one TDMA time slot is included in the optical wireless TD-CDMA time slot train, it is possible to cope with a user having a large transmission capacity. Embodiment 3.

FIG. 7 is an explanatory view showing still another example of the spectrum configuration of the optical / radio wave shared communication system.

By assigning a time slot # 71- 23 A, which is a composite of multiple time slots, to the user in the optical wireless time slot train, one time slot (for example, # 27-4 A) Can be used for users who require high-speed transmission rather than assigning time slots. (By assigning a time slot in which multiple time slots are combined to a time slot in the radio wave spectrum area, high-speed transmission is possible.) May be supported).

FIG. 7 shows a case in which two time slots are combined and one combined time slot is used.The force is not limited to this.A plurality of arbitrary time slots are combined and one time slot is combined. A composite time slot may be used.

In particular, if a plurality of optical TDMA time slots are consecutively allocated to one user (for example, time slot # 71-23A and time slot # 61-1A are consecutively arranged in the time-series axis direction). ), Which can dramatically increase the transmission speed.

By taking an arbitrary number of time slots as one time slot, it is possible to assign an arbitrary speed to a user. Embodiment 4.

Fig. 8 shows that the control channel of the optical wireless spectrum band is set to "low-speed multi-channel optical wireless TD-C DMA slot # 82-OA", and the control channel of the radio wireless spectrum band is set to "low speed". Multi-channel TD—CDMA slot # 8 1 — 1 A ”.

Next, a detailed operation when the base station 3 and the subscriber station 9 execute wireless communication will be described.

First, when the base station 3 and the subscriber station 9 perform wireless communication, the subscriber station 9 performs the same as the own station slot # 8 1, as in the case of performing communication using a normal radio wave radio line. Using 1A, the base station 3 receives a broadcast channel (a common channel received first by all subscriber stations), which is a control channel transmitted in time division CDMA format.

The broadcast channel includes an identification code indicating that the base station 3 has an optical wireless communication function, in addition to the unique information of the base station 3.

When receiving the broadcast channel, the subscriber station 9 decodes the information of the broadcast channel and recognizes the spread code of the control channel that can be received by the base station 3 at present.

Then, the subscriber station 9 transmits a call signal to the base station by radio wave using the Up-Link slot # 81 10B control channel indicated by the spreading code (step ST11). ).

In this case, an identification code indicating that the subscriber station 9 has a function corresponding to the optical wireless communication is included in the call signal and transmitted.

However, if the subscriber station 9 does not have a function corresponding to the optical wireless communication (step ST12), since the optical wireless line cannot be connected, only the wireless communication using the normal radio wave wireless line is performed. It is executed (step ST 13). Since this part is the same as the conventional communication, the description is omitted.

When the base station 3 receives a call signal including an identification code indicating that the base station 3 has a function corresponding to the optical wireless communication from the subscriber station 9, the base station 3 The information of the optical wireless line to be used by the subscriber station 9 (for example, optical wireless line slot # 27-2A / # 2 At 7-1B, the subscriber station 9 is transmitted to the subscriber station 9 (such as the spreading code designation number of the communication channel of the optical wireless line allocated to the subscriber station 9) (step ST14).

When the subscriber station 9 receives the information on the optical wireless link, the subscriber station 9 transmits the optical link through the communication channel that can be used with the designated spreading code in the Uplink slot # 27-1B in the optical wireless link. An outgoing call signal of the wireless line is optically wirelessly transmitted to the base station 3 (step ST15).

The base station 3 detects the optical signal (call signal) based on the designated time slot and spread code to receive the call signal of the optical wireless line.

If the base station 3 can detect the optical signal, it determines that the connection of the optical wireless line (Up-Link line) has been completed (step ST16), and determines the own link in the optical wireless line. The line is set, and sharing of the radio wave line and the optical line is started (step ST17).

On the other hand, if the optical signal cannot be detected, it is determined whether or not the subscriber station 9 has already tried the transmission processing of the call signal at least n times (step ST 19). If so, the connection of the optical wireless line is abandoned, and only the wireless wireless communication is performed (step ST 20).

When the base station 3 and the subscriber station 9 start sharing the radio radio line and the optical radio line, for example, according to the transmission capacity and transmission speed, or the use environment of the line (transmission error occurrence status), A convenient wireless line is selected, and radio wave communication or optical wireless communication is executed (step ST 18).

Then, when terminating the wireless communication, the optical wireless line is disconnected first, and then the radio wave wireless line is disconnected to complete the wireless communication (step ST21).

) o As is clear from the above, according to the fourth embodiment, the connection of the radio radio line is continued even after the optical radio line is connected, so that the radio radio line and the optical radio line can be shared. In addition to this, there is an effect that the radio wave radio line can function as a protection means for the optical radio line.

Also, there is an effect that the connection of the control signal can be maintained even when the connection of the optical wireless line is disconnected. Embodiment 5

FIG. 10 is a flowchart showing a recovery procedure when the optical wireless line is disconnected while the radio wave wireless line and the optical wireless line are shared.

First, the subscriber station 9 monitors whether or not the connection of the optical wireless line is continued while the radio wireless line and the optical wireless line are shared (steps ST31 and ST32), and When the line disconnection is detected, a recall signal of the optical wireless line is transmitted to the base station 3 through the control channel of the radio wave wireless line (step ST33).

The base station 3 monitors the reception of the re-calling signal transmitted by the subscriber station 9 (step ST34), and upon receiving the re-calling signal of the optical wireless line, receives the necessary line such as the address of the optical wireless line. The information is transmitted to the subscriber station 9 (step ST35).

When receiving the line information of the optical wireless line, the subscriber station 9 transmits the optical wireless signal to the base station 3 again through the upstream optical wireless line specified by the line information, and restarts the execution of the optical wireless communication. Attempt (step ST36).

Then, when the base station 3 receives the optical wireless signal transmitted from the subscriber station 9, the base station 3 transmits the optical wireless signal to the subscriber station 9 through a downstream optical wireless line, and the subscriber station 9 If the optical wireless signal is successfully received, reconnection of the optical wireless line is completed. When the reconnection of the optical wireless line is completed (step ST37), the base station 3 and the subscriber station 9 resume sharing of the radio wireless line and the optical wireless line (step ST38).

However, since reconnection of the optical wireless line is not always successful, if reconnection is not possible, only wireless communication using the radio wave radio line will be continued.

Due to the straightness of the light of the optical wireless line, if the direction of the equipment at the subscriber station changes, there is a high possibility that the line connected between the base station and the subscriber station will be disconnected. Therefore, when the subscriber station is a mobile station, the function of automatically detecting the disconnection of the optical wireless line and automatically resetting the line by radio wave communication is important. The fifth embodiment has an effect of enhancing the system function as an example. Embodiment 6

In the above fifth embodiment, the case where the optical wireless circuit is reconnected when the line disconnection of the optical wireless line is detected has been described. However, the direction of the optical wireless transmitting / receiving antenna 11 of the subscriber station 9 is changed to the optical wireless line. By adjusting to the direction in which the base station to which the line is connected exists, the communication environment of the optical wireless line may be enhanced to prevent line disconnection.

Specifically, as shown in FIG. 11, 9 subscriber stations capable of receiving radio waves from a plurality of base stations 3, 6, 12 are radio waves from 9 base stations 3, 6, 12 By measuring the delay time of the subscriber station 9, the position of the subscriber station 9 itself is measured. In the figure, 13 is a radio transmission / reception antenna of the base station 12, and 14 is an optical radio transmission / reception antenna of the base station 12.

Here, the method by which the subscriber station achieves frame synchronization with a plurality of base stations is disclosed in our patent application PCT / JP97 / 027990. Of the multiple base stations that have achieved frame synchronization, radio waves are received from at least three base stations and the delay time of these radio waves is measured to determine the position of the subscriber station. However, since the position of each base station is registered in advance, if the delay time of the radio wave is known, the distance to each base station can be known, and if the distance to three or more base stations is known, geometrically The location of the subscriber station is known).

Then, when the subscriber station 9 measures its own position, it recognizes in advance the position of the base station to which the optical wireless line is to be connected (here, the base station 6 is to be connected). Therefore, the direction of the optical wireless transmission / reception antenna 11 of the subscriber station 9 with respect to the base station 6 can be recognized.

Therefore, when the subscriber station 9 measures its own position, the antenna control device described later adjusts the direction of the optical wireless transmission / reception antenna 11 to the direction in which the base station 6 exists.

Thereby, even if the optical wireless transmitting / receiving antenna 11 of the subscriber station 9 has directivity, it is possible to efficiently communicate the optical wireless signal.

The direction of the directivity of the optical wireless transmission / reception antenna 11 may be changed by mechanically rotating or moving the antenna up or down, or by changing the direction electronically.

FIG. 12 is a block diagram showing the inside of the subscriber station 9. In the figure, the same reference numerals as those in FIG. 4 denote the same or corresponding parts, and a description thereof will be omitted.

3 8 is a GPS receiver that detects the position of the subscriber station 9, 3 9 is a far north detector that detects the direction of the optical wireless transmission / reception antenna 11, and 40 is a radio wave transmitted from multiple base stations The position of the subscriber station 9 is calculated from the delay time of the optical transmission / reception antenna 11 based on the calculation result or the detection result of the GPS receiver 39 and the direction report of the far north detector 39. This is an antenna control device that drives and controls the bearing. FIG. 13 is a flowchart showing the directivity pointing process of the optical antenna.

Here, it is assumed that a radio wave radio line has already been connected between base station 6 and subscriber station 9 in step ST41.

In this state, the subscriber station 9 transmits a call signal for setting up the optical wireless line to the base station 6 through the control channel of the radio wave wireless line.

Then, upon receiving the outgoing signal of the optical wireless line transmitted from the subscriber station 9 (step ST42), the base station 6 starts transmission of the optical wireless signal using the downstream optical wireless line.

On the other hand, the antenna control device 40 of the subscriber station 9 detects a delay time of radio waves transmitted from a plurality of base stations and executes a process of detecting its own position. However, in the case where radio waves cannot be received from a plurality of base stations, the position of the terminal is grasped from the detection result of the GPS receiver 38.

When the antenna control device 40 of the subscriber station 9 detects its own position, the position information and the azimuth information of the far north detector 39 (the position information of the far north detector 39 are based on the optical wireless transmission / reception). It is used to know the current direction of the antenna 11 for use, but it is not essential information) to recognize the direction in which the base station 6 exists. However, the position of the base station 6 is known in advance.

When the antenna control device 40 of the subscriber station 9 grasps the direction in which the base station 6 exists, the antenna control device 40 drives and controls the optical wireless transmitting / receiving antenna 11 to change the orientation of the optical wireless transmitting / receiving antenna 11 to the base station 6. A process is performed to match the direction in which there is (step ST43).

When the subscriber station 9 drives and controls the optical wireless transmission / reception antenna 11, it monitors the reception of the optical wireless signal transmitted by the base station 6 (step ST 44). An optical wireless signal is transmitted to the base station 6 via the wireless line, and an attempt is made to execute optical wireless communication (step ST45). Then, when the base station 6 succeeds in receiving the optical wireless signal transmitted from the subscriber station 9, the connection of the optical wireless line is completed.

When the connection of the optical wireless line is completed (step ST46), the base station 6 and the subscriber station 9 start sharing the optical wireless line and the optical wireless line (step ST47).

As is clear from the above, according to the sixth embodiment, the direction in which the base station 6 to be connected to the optical wireless line exists is detected, and the base station 6 determines the direction of the optical wireless transmitting / receiving antenna 11. Since the configuration is such that the direction is set to exist, the communication environment of the optical wireless line is enhanced, and it is possible to efficiently communicate the optical wireless signal and to prevent the disconnection of the optical wireless line. .

Although the sixth embodiment has been described with reference to the case where the subscriber station 9 detects the direction in which the base station 6 exists, the base station 6 detects the direction in which the base station 6 exists relative to the subscriber station 9. Alternatively, the subscriber station 9 may receive information indicating the direction of existence from the base station 6. Industrial applicability

As described above, the wireless communication system according to the present invention uses a time division multiplex access method, a code division multiple access method, a time division two-way method, or a time division CDMA method to establish a wireless base station and a subscriber station. It is suitable for performing wireless communication by selectively using a wireless line with excellent line conditions when communicating.

Claims

δ 冃 range

1. When a base station is connected to the public network via a mobile switching center via a wired or wireless connection, and the base station is connected to a radio wave radio line, the base station performs radio communication using a digital modulation method. In a wireless communication system including a subscriber station, the base station and the subscriber station connect an optical wireless line having a common layer structure on the time axis to the wireless wireless line in addition to the wireless wireless line. Wireless communication using a digital modulation method.

2. The base station and the subscriber station perform synchronization between the radio radio line and the optical radio line in units of time slot, frame, multiframe or super multiframe. 2. The wireless communication system according to claim 1.

3. The base station and the subscriber station arbitrarily arrange the TD Μ Α signal and the time-division CD Μ Α signal in the time slot train constituted by the radio wave radio line and the optical radio line. 2. The wireless communication system according to claim 1, wherein

4. The wireless communication system according to claim 1, wherein the base station and the subscriber station connect an optical wireless line after connecting the radio wave wireless line.

5. The wireless communication system according to claim 1, wherein, when terminating the wireless communication, the base station and the subscriber station disconnect the optical wireless line and then disconnect the radio wave wireless line.

6. The scope of the request, wherein the base station and the subscriber station attempt to reconnect the optical wireless line when the disconnection of the optical wireless line is detected during the wireless communication. A wireless communication system according to claim 1.

7. When the base station and the subscriber station set the break position between the uplink and the downlink in the radio wave radio line and the break position between the uplink and the downlink in the optical radio line, the base station and the subscriber station must set different time positions in the frame. 2. The wireless communication system according to claim 1, wherein setting is permitted.

8. The radio wave circuit and the optical radio line to which the base station and the subscriber station are connected have a common layer structure on a time axis and have mutually different slot structures. The wireless communication system according to item 1.

9. The wireless communication system according to claim 8, wherein the base station and the subscriber station use a plurality of time slots as one composite time slot.

10. The wireless communication system according to claim 9, wherein the base station and the subscriber station combine a plurality of continuous time slots on a time axis.

11. The wireless communication system according to claim 1, wherein the subscriber station detects the direction in which the base station exists, and sets the direction of the optical antenna to the direction in which the base station exists. system.

1 2. The subscriber station receives, from the base station, information indicating the direction in which the base station exists, and sets the direction of the optical antenna to the direction in which the base station exists. 2. The wireless communication system according to claim 1.

13. The wireless communication system according to claim 11, wherein the subscriber station measures its own location and detects the direction in which the base station exists.

13. The wireless communication system according to claim 12, wherein the subscriber station measures a time difference between radio waves arriving from a plurality of base stations to measure its own location.

15. The wireless communication system according to claim 12, wherein the subscriber station measures its own location using a GPS receiver.