JPH05304526A - Domestic network equipment - Google Patents

Abstract

PURPOSE:To realize the domestic radio network equipment with simple and inexpensive line configuration in which a high-speed broad-band signal is transmitted with high reliability. CONSTITUTION:This domestic network equipment has a radio wave zone composed of a master transmitter-receiver 3 provided with an antenna 3a mounted to a high position such as a ceiling, directed downward and having a sufficiently wide radiation characteristic and an optional number of slave transmitters- receivers 5 mounted on a low position such as a desk and exchanging data with the master transmitter-receiver 3, and each of the slave transmitters- receivers 5 is provided with an antenna 5a having a sufficiently narrow angular radiation characteristic and a layer including a substance absorbing a radio wave for an operating frequency band is provided at the ceiling or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network device in a premises, and more particularly to a network device in a premises by wireless communication.

[0002]

2. Description of the Related Art A network device on a premises (hereinafter, referred to as "terminal device") for connecting a plurality of data terminal devices (hereinafter simply referred to as "terminal devices") installed in a room and a parent system by a communication line.
Conventionally, a method of arranging conductor lines corresponding to the number of terminal devices in a room has been adopted in the (LAN).

This method has the advantage of high communication reliability, but on the other hand, every time the number of terminal devices installed or the installation location changes, the work of laying or relocating the line must be carried out. , Cabinets, chairs, etc. (hereinafter,
There is a drawback in that a great deal of labor, time and cost are spent because the movement of a desk or the like) must be performed together.

On the other hand, there has been proposed a network system (wireless LAN) in which each terminal device is provided with a wireless interface and a radio frequency is used. The wireless LAN has the advantage that it does not require line laying work even if the number of terminal devices installed increases, but currently available systems are VHF (ultra high frequency) band and UHF (ultra high frequency). Because it uses weak band or low power radio waves,
There is a limitation in the frequency bandwidth that can be used, and therefore, only a communication speed of several kilobauds to several tens of kilobauds can be obtained, which is not suitable for transmission of high-speed wideband signals.

Further, a network device (hereinafter, referred to as an optical LAN) in a premises that uses light has been proposed. Optical LAN
Is suitable for transmission of high-speed wideband signals, but has the drawback that the reliability of the line is low because the optical line is blocked even with a thin sheet of paper.

In order to improve these drawbacks, a wireless LAN (called WIN; IEEE N) using the quasi-millimeter wave band is used.
etwork Magazine, November 1991, P21-P26) has been proposed. Since this WIN uses extremely high radio frequencies, it is not only suitable for transmission of high-speed wideband signals, but also
Even if the transmitter and the receiver are cut off from each other by a paper sheet or a curtain, the communication is possible because of the radio waves. In addition to the directly propagating waves from the transmitter to the receiver, many reflected waves generated on the wall surface of the room or the surface of the library enter the receiver. In this case, since each reflected wave jumps in from all unspecified directions, a slight difference in propagation time causes interference between the direct wave and the reflected wave, and also between the reflected waves, causing a desk or the like on the premises. Data may not be normally transmitted depending on the arrangement of the walls and walls. WIN solves this problem with a circuit configuration.

[0007]

The circuit of the above-described structure of WIN has a plurality of antennas so as to selectively receive only an appropriate one wave from many received waves, and these antennas are provided in different directions. A receiver that can receive multiple received waves corresponding to each antenna, a switching circuit that selects an appropriate one of these received signals, and a switching circuit that determines which wave is appropriate. Since it is composed of a circuit for controlling the device, the device becomes extremely complicated and diversified. Therefore, the WIN system has a drawback that it is not suitable for downsizing and cost reduction.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a network device in a premises capable of transmitting a high-speed wideband signal with high reliability by a simple and inexpensive line configuration. There is.

[0009]

In order to solve the above-mentioned problems, a network device in a premises according to claim 1 of the present invention is installed at a high position such as a ceiling, and has a sufficiently wide angle. The radio wave zone composed of a parent transceiver equipped with an antenna having the radiation characteristics of, and an arbitrary number of child transceivers that are placed at a low position such as a desk and exchange data with the parent transceiver. In the existing network device, the slave transceiver is provided with an antenna having a sufficiently narrow-angle radiation characteristic, and the ceiling or the like contains a substance that absorbs radio waves in the used frequency band. The feature is that layers are provided.

[0010]

According to the above configuration of the present invention, the parent transceiver 3,
... and the slave transceivers 5, ... can receive only direct waves (of high-speed wideband signals) by their respective antennas,
An extra antenna for antenna diversity, a selection circuit for selecting only one wave from a plurality of reflected waves, and a control circuit therefor are unnecessary. For this reason,
The circuit configuration can be further simplified, and a small-sized and inexpensive network device in the premises can be realized.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic plan view for explaining a network device in a premises which is an embodiment of the present invention, and FIG. 2 is a side view of the same.

In these drawings, reference numeral 1 denotes an indoor space such as an office, and the indoor space 1 has a plurality of radio wave zones 1a, 1a.
b, ... Are set. 2 is each radio wave zone 1a, 1
The desks, etc., arranged in b, ... Are parent transceivers (hereinafter referred to as parent machines) mounted on the ceiling 4 for each radio wave zone 1a, 1b ,. Is a single transceiver or a plurality of slave transceivers (hereinafter, referred to as slaves) arranged in each zone 1a, 1b, ....

The parent devices 3, ... Are provided with transmitting and receiving antennas 3a, ... In which the radiation pattern angle .theta. Of the radio waves is large enough to allow the radio wave zones 1a, 1b ,. On the other hand, the slave units 5, ... Are provided with transmitting and receiving antennas 5a, .. The radio wave radiation pattern angle α is sufficiently smaller than the radiation pattern angle α of the master unit.

The above-mentioned parent device 3, ... And the child device 5, ... constitute a LAN according to the embodiment of the present invention. .. are connected to each other by a communication line of another frequency band (for example, an optical fiber line or a baseband transmission line), and a parent system is configured as a whole.

In the LAN of this example described above, the transmission frequency of the slave units 5, ... (Reception of the master unit) and the transmission frequency of the master units 3 ,. ing. In order to separate and identify these frequencies, the main unit 3, ... Is provided with a small and simple filter circuit.

Next, the ceiling 4 is covered with a radio wave absorber having a large absorption and attenuation with respect to the frequencies used in this embodiment. Of the radio waves radiated from the slave units 5, ... The rest of the radio waves that are not received by base unit 3, ... Are absorbed by this radio wave absorbing plate. In this way, the reflected wave from the ceiling 4 does not reach the antennas of the slave units 5, ....

The radio waves radiated from the base units 3, ... Are reflected by the indoor desk 2 and the floor and the like, and the reflected power is not necessarily small. Therefore, the radio waves radiated by the parent device 3, ... Are reflected again from the desk 2 and the like, and the parent device 3 ,.
Is likely to be received by the slave unit 5, as described above.
Since the transmission frequency of ... (that is, the reception of the master unit) and the transmission frequency of the master unit 3, ... are set to be slightly different,
There is no problem.

Further, since the radio waves radiated from the parent device 5, ... And reflected by the floor or desk 2 are absorbed by the radio wave absorbing plate of the ceiling part 4, the antennas 5a ,. Since the reflected waves of the radio waves transmitted from the base units 3, ... Are hardly received, no trouble occurs.

In the above-mentioned structure, the transmittable / receivable range of the base units 3, ... Is within the angle θ of the radio wave radiation pattern, while the transmittable / receivable range of the slave units 5 ,. This is within the angle α of the sharp radiation pattern due to the characteristics of the antennas 5a, ... Of the slave unit. In this way, the slave units 5, ... Align the directions of the antennas 5a, ... With the master units 3, .. of the radio wave zones 1a, 1b ,.
Exchange information with the parent system, and the relevant radio zone 1
Data is exchanged with other slave units 5, ... Of a, 1b ,.

According to the above configuration, the ratio (D / U) of the direct wave (D) and the reflected wave (U) in the received wave can be increased, so that a highly reliable system can be obtained. it can.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like within the scope not departing from the gist of the present invention. Also included in this invention. For example, in the above-described embodiment, the case where the master transceiver is arranged on the ceiling has been described. However, only the antenna may be arranged on the ceiling, and the master body may be arranged on a desk or the like.

Further, the above-mentioned radio wave zones 1a, 1b, ...
The boundary is not so strict, and as shown in FIG. 1, a plurality of radio wave zones may overlap in the vicinity of the boundary. By doing so, the slave unit in the overlapping zone can select the master unit only by matching the directions of the antennas. It is possible to exchange data with a slave unit in another radio wave zone via the selected master unit. There may be a single radio wave zone or a plurality of radio wave zones.

It is important to make the antenna radiation angle α of the master unit sufficiently large to the extent that it is not so difficult to match the direction of the antenna when installing the slave unit.

[0024]

As described above, according to the network device in the premises of the present invention, both the base units 3, ... And the handset units 5 ,.
Since each antenna can receive only the direct wave of (high-speed wideband signal), an extra antenna for antenna diversity, a selection circuit for selecting only one wave from a plurality of reflected waves, and a control therefor No circuit is needed. Therefore, the circuit configuration can be further simplified, and a small-sized and inexpensive network device in the premises can be realized.

[Brief description of drawings]

FIG. 1 is a schematic plan view for explaining a network device in a premises which is an embodiment of the present invention.

FIG. 2 is a schematic side view of FIG.

[Explanation of symbols]

 1a, 1b, ... Radio wave zone 2 Desks, etc. 3, Master unit (master transceiver) 3a Antenna 5, ... Slave unit (slave transceiver) 5a Antenna

Claims (1)

[Claims] 1. A parent transceiver which is mounted at a high position such as a ceiling and which is provided with an antenna having a sufficiently wide-angle radiation characteristic and which is directed downward, and a parent transceiver which is placed at a low position such as a desk and which has the parent. A network device in a premises in which a radio wave zone configured by a transceiver and an arbitrary number of slave transceivers for exchanging data exists, wherein the slave transceiver includes an antenna having a sufficiently narrow-angle radiation characteristic. Be prepared,
A network device in a premises, wherein a layer containing a substance that absorbs radio waves in the used frequency band is provided on the ceiling or the like.