JP2817023B2 - Millimeter wave wireless LAN system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a LAN (Local Area N)
The present invention relates to a wireless LAN system using radio waves in a millimeter wave band.

[0002]

2. Description of the Related Art Wireless communication in a millimeter wave band (particularly a 60 GHz band) or a similar frequency band has a large spatial propagation loss. In a private wireless LAN system that is expected to be developed and spread in the future, semi-fixed LAN devices using a millimeter wave band radio wave as a medium in high-speed and ultra-high-speed areas are considered to be developed. As shown in FIG. 6, the LAN communication in this case includes a millimeter-wave band wireless terminal station (slave station) 52A to 52C attached to a wireless terminal and a wireless LAN wireless base station attached to a ceiling. (Master station) 51. As the antenna on the master station side, an antenna having a wide-angle beam characteristic is used so as to cover a wide area in a premises or a room. On the other hand, on the slave station side, an antenna having a narrow-angle beam characteristic is used in order to eliminate multiple reflection signals as much as possible and to secure a necessary antenna gain.

[0003]

However, in the case of the above-mentioned conventional private wireless LAN system, since the millimeter wave charged wave has a very high straightness, it may be behind a person, an object, or indoor furniture. There is a possibility that a problem of radio wave non-arrival due to “shadowing” that the radio wave does not reach that location may occur. Specifically, the following cases can be considered. Communication interruption due to shadowing of people and things. Communication interruption due to wireless terminal displacement. FIG. 6 shows an assumed diagram of the occurrence of shadowing due to the above-described cause in the office. In the slave stations 52A and 52C, shadowing is caused by a person and radio waves from the master station 51 do not reach. It is shown. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a millimeter-wave wireless LAN system that can recover even if a communication interruption due to shadowing or the like occurs.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a millimeter-wave wireless LAN system according to the present invention uses a millimeter-wave band radio wave and a radio base station provided on a ceiling side and a desk-top. In a millimeter-wave wireless LAN system for performing communication with a wireless terminal station, a carrier detection circuit, a timer circuit, a cutoff error identification circuit, and an alarm circuit are built in the wireless terminal station, and the communication is interrupted. In such a case, a warning is issued by sound or light.

[0005]

According to the present invention having the above configuration, the wireless terminal station incorporates a carrier detection circuit, a timer circuit, a cutoff error identification circuit, and an alarm circuit so that when communication is cut off due to shadowing or the like, sound or light A warning can be issued.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. A wireless base station (master station) 1 and a wireless terminal station (slave station) 2 in a millimeter-wave wireless LAN system according to an embodiment of the present invention.
FIG. 1 shows a block configuration related to information transmission between them.

As shown in FIG. 1, when the flow of information from the master station 1 to the slave station 2 is viewed, communication information is transmitted from an Ethernet cable 11 disposed on a ceiling or the like of a premises to a wired LAN. / Wireless LAN interface 12 to perform conversion from wired to wireless and transmit / receive modem BB circuit 1
3 and the millimeter wave transmission / reception unit 14, and are transmitted from the millimeter wave transmission / reception antenna unit (master station antenna unit) 15 to the slave station 2 as millimeter wave radio waves.

On the slave station 2 side, the above-mentioned millimeter wave radio wave enters a millimeter wave transmitting / receiving antenna section (slave station antenna section) 21.
Next, the data is converted from wireless to wired via the wireless LAN / wired LAN interface unit 24 via the millimeter wave transmitting / receiving unit 22 and the transmission / reception modulation / demodulation unit BB circuit 23, and passed through the physical layer 25 and the data link layer 26 to the OA terminal. Enter 27.

In the following embodiment, when a communication interruption occurs between the master station 1 and the slave station 2 due to shadowing by the shadowing object 3 or the like, the data link layer 26 in the block diagram of FIG. A special function is added to a logic circuit provided in the inside, and the following three steps of the logic flow are targeted. Line status monitoring process (waiting state) flowchart (see FIG. 2) Data transmission process flowchart (see FIG. 3) Data receiving process flowchart (see FIG. 4)

Note that the determination of these steps is made by the master station 1
Although it is possible to use either of the slave station and the slave station 2, in the following embodiment, it is assumed that the slave station 2 always has the data link layer 26.

Hereinafter, embodiments of the present invention will be described. FIG. 2 is a flowchart showing the operation procedure of the millimeter-wave wireless LAN system according to the first embodiment which is an embodiment in a line state monitoring process in Ethernet. In the drawing, the flowcharts (steps S3 to S8) indicated by solid lines are based on the data link protocol of the IEEE (Institute of Electrical and Electronics Engineers) 802.2 committee.

A flowchart (steps S1, S2, S9 to S12) indicated by a broken line in FIG. 2 is a flowchart relating to an additional function for detecting communication interruption, which is a characteristic part of the present embodiment. In the conventional wireless LAN system (steps S3 to S8) indicated by a solid line in the figure, it is constantly checked whether a signal is being transmitted from another station on the line and whether the line can be used (step S3).
3, S5), the line is switched to the busy state or the ready state (steps S4, S7).

[0013] In the conventional system, even if the communication is interrupted at this time, there is no system that issues an alarm or the like for communication interruption. In the present embodiment, a flowchart (steps S1, S2, S9-S1
2) is added. That is, determination of presence / absence of an empty carrier (carrier) (step S1), and a timer (steps S9 and S10: can be set within a range of several seconds to several tens of seconds. In this embodiment, set to 5 seconds). Then, the occurrence of a communication interruption error is identified (step S11), and a warning is issued by voice (step S12). As a result, it is possible to notify a nearby person or the like of the occurrence of a communication interruption error in the line monitoring process, thereby facilitating recovery.

FIG. 5 is a block diagram showing a means for executing the above procedure. That is, in response to a command from the data link layer logic circuit 41 for executing the entire flowchart of FIG. 2, the carrier detection circuit 42 determines whether or not there is an empty carrier (step S1). Detects a predetermined time (5 seconds in this embodiment) (steps S9 and S10). When the predetermined time elapses, the interruption error detection circuit 44 identifies whether or not a communication interruption error has occurred (step S11). In response, the voice transmitting circuit 45 issues a warning by voice (step S12).

FIG. 3 is a flowchart showing an operation procedure of the millimeter wave wireless LAN system according to the second embodiment which is an embodiment in a data transmission process in the Ethernet. In FIG. 3, the flowchart of the solid line portion (steps S21 to S21)
23, S26 to S32) correspond to the conventional IEEE 802.2.
It is based on the Commission's data link protocol.

The flowchart of the broken line portion (step S2)
4, S25, S33 to S36) are flowcharts relating to an additional function for detecting a communication interruption, which is a characteristic part of the present embodiment. A conventional wireless LA shown by a solid line in the figure.
In the N system, transmission is performed while performing collision detection on the line (step S26).

In the conventional system, even if the communication is interrupted at this time, there is no system that identifies the communication interruption and issues an alarm or the like. In the present embodiment, a flowchart (steps S24, S25, S
33 to S36) are added. That is, it is possible to determine whether or not there is a carrier (step S24) and set a timer (steps S33, S34: several seconds to several tens of seconds).
In the case of this embodiment, it is set to 5 seconds. ), The occurrence of a communication interruption error at the time of transmission is identified (step S35), and a warning is issued by voice (step S36). This allows
It is possible to notify a nearby person or the like of the occurrence of a communication interruption error in the transmission process, thereby facilitating recovery. FIG. 5 is a block diagram showing a means for executing the above procedure.

FIG. 4 is a flowchart showing the operation procedure of the millimeter-wave wireless LAN system according to the third embodiment which is an embodiment in the data receiving process in the Ethernet. In FIG. 4, the flowchart of the solid line portion (steps S41 and S41)
44 to S54) are based on the data link protocol of the conventional IEEE 802.2 committee.

The flowchart of the broken line portion (step S4)
2, S43, S55 to S58) are flowcharts related to an additional function for detecting communication interruption, which is a characteristic part of the present embodiment. A conventional wireless LA shown by a solid line in the figure.
In the N system, all data on the line is received (step S
Then, the frame length and address are checked (steps S45 and S46), and after unnecessary data is discarded, an error is detected by FCS (frame check sequence) (step S47) and the like.

In the conventional system, even if the communication is interrupted at this time, there is no system that identifies the communication interruption and issues an alarm or the like. In the present embodiment, a flowchart (steps S42, S43,
S55 to S58) are added. That is, it is possible to determine whether or not there is a carrier (step S42) and set a timer (steps S55 and S56: several seconds to several tens of seconds).
In the case of this embodiment, it is set to 5 seconds. ), The occurrence of a communication interruption error at the time of reception is identified (step S57), and a warning is issued by voice (step S58). This allows
It is possible to notify a nearby person or the like of the occurrence of a communication interruption error in the receiving process, thereby promoting recovery. FIG. 5 is a block diagram showing a means for executing the above procedure.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the claims of the present invention, and any device having the same function and effect can be realized by the present invention. It is included in the technical scope of the invention.

For example, in each of the above embodiments, an example has been described in which a warning is issued by voice when a communication interruption error occurs. However, the present invention is not limited to this, and other means,
For example, a warning may be given by a buzzer sound, or a warning may be given by light.

[0023]

As described above, according to the present invention having the above-described structure, a radio terminal station provided on a desk has a carrier detection circuit, a timer circuit, a cut-off error identification circuit, and an alarm circuit incorporated therein, and performs shadowing. When communication is interrupted due to, for example, a warning can be issued by sound or light.
Therefore, it is possible to notify a nearby person or the like of the occurrence of the communication interruption error and to promote the recovery, so that a person or an object obstructing the communication can be quickly eliminated, and the communication interruption time due to the cause can be eliminated. Can be minimized,
There is an advantage. In addition, there is an advantage that the positional deviation of the wireless terminal can be quickly found and corrected, thereby minimizing the communication interruption time.

[Brief description of the drawings]

FIG. 1 is a diagram showing a block configuration relating to information transmission between a master station and a slave station in a millimeter wave wireless LAN system according to an embodiment of the present invention.

FIG. 2 is a flowchart (1) showing a configuration of a procedure regarding information transmission between a master station and a slave station in the millimeter wave wireless LAN system shown in FIG.

FIG. 3 is a flowchart (2) showing a configuration of a procedure regarding information transmission between a master station and a slave station in the millimeter wave wireless LAN system shown in FIG.

FIG. 4 is a flowchart (3) showing a configuration of a procedure regarding information transmission between a master station and a slave station in the millimeter wave wireless LAN system shown in FIG.

5 is a block diagram showing a configuration of a logic circuit and the like in a data link layer in the millimeter wave wireless LAN system shown in FIG.

FIG. 6 is a diagram illustrating a problem in a conventional LAN system.

[Explanation of symbols]

 Reference Signs List 1 wireless base station 2 wireless terminal station 3 shadowing object 11 Ethernet cable 12 wired LAN / wireless LAN interface 13 transmission / reception modulation / demodulation unit BB circuit 14 millimeter wave transmission / reception unit 15 millimeter wave transmission / reception antenna unit 21 millimeter wave transmission / reception antenna unit 22 millimeter wave transmission / reception unit Reference Signs List 23 transmission / reception modulation / demodulation unit BB circuit 24 wireless LAN / wired LAN interface 25 physical layer 26 data link layer 27 OA terminal 41 data link layer logic circuit 42 carrier detection circuit 43 timer circuit 44 cutoff error identification circuit 45 voice transmission circuit 51 wireless base station 52A To 52C wireless terminal station S1 to S58 Step

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04L 12/28 H04B 7/26

Claims (1)

(57) [Claims] 1. A millimeter-wave wireless LAN system for performing communication between a wireless base station provided on a ceiling side and a wireless terminal station provided on a desk side using millimeter-wave band radio waves, A millimeter-wave wireless LAN system in which a wireless terminal station incorporates a carrier detection circuit, a timer circuit, an interruption error identification circuit, and an alarm circuit, and issues an alarm by sound or light when communication is interrupted.