JPH0722266B2 - Wireless communication system in a narrow space - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wireless communication system using a transponding card installed in a room where radio waves are likely to be reflected. The transponding card (hereinafter referred to as TRC) is an IC card with a wireless communication function.

(Prior Art) In recent years, the construction of intelligent buildings that have both advanced information and communication functions and building management functions has progressed, and users in those buildings have become able to enjoy efficient and comfortable activities. There is.

As a means for constructing such a communication system for an intelligent building, various communication systems using TRC have already been proposed by the same applicant.

Under such circumstances, when identifying the position of a person with a TRC wirelessly, in a narrow space such as a room, a radio wave is reflected by a wall and a standing wave is generated, resulting in an unidentifiable point. Become. If there is a person who is stationary at such a point for a long time, there is a problem that the position of that person cannot be detected.

FIG. 2 is a diagram for explaining the influence of reflected waves in the radio communication system in such a narrow space, in which 1 is a fixed station radio (TRX), 2 is an antenna (ANT), 3 is TRC, 4
Is a processing device, 5 is a room such as an intelligent building forming a narrow space, and 6 is a wall of the room.

Here, the structure of the TRC will be described with reference to FIG. 3. The TRC3 is configured as a light, thin, short, and small card that can be easily worn by the user, and the management and control of the entire TRC is performed. Control unit 3-1, which performs the wireless communication control procedure, the memory 3-2 which stores the ID (personal identification) code and position information of the TRC itself, the wireless transmission / reception unit 3-3 which performs wireless transmission / reception with the TRX1, and the ID code. A key input section 3-4 for inputting data such as, a power supply section 3-5 for supplying electric power to each section in the TRC are built-in.

Therefore, as shown in Fig. 2 (a), the transmission signal from TRX1 is combined with the direct wave and the reflected wave via ANT2, and TR is transmitted.
Although it enters C3, depending on the position, the reception input level lowers and communication becomes impossible due to the phase relationship, as shown in FIG. 2 (b).

By the way, conventionally, space diversity is generally used as a measure against fading. That is, when the refractive index of the atmosphere changes, interference of multiple waves at the receiving point, focusing / divergence of radio waves, or diffraction due to obstacles change, and as a method of reducing fading that changes the received power with time, Diversity is used.

FIG. 4 is a block diagram of such space diversity. In the figure, 10 is a transmitter, 11 and 12 are receivers, 13 is a processor, and 1 is a receiver.
4 is ANT.

As shown in this figure, this space diversity complicates the configuration, such as requiring two receiving systems, and is applicable to communication systems using TRCs that are compact and inexpensive. Had a problem.

Further, the conventional space diversity is for reducing fading when performing communication by radio waves in the outdoor space, as described above.

(Problems to be Solved by the Invention) As described above, in the conventional communication system, the reception input level is lowered due to the phase relationship depending on the position, and the communication becomes impossible. When space diversity was adopted for communication, the configuration became complicated, it was not technically good, and it was not economical, and there was a problem in constructing a communication method using TRC.

The present invention eliminates the above-mentioned problems and provides a wireless communication system in a narrow space which has a simple structure and can economically reduce the number of incommunicable points without changing the structure of the TRC. To aim.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a method for fixing a room in a wireless communication system in a narrow space in which wireless communication is performed in an environment in which radio waves in the room tend to generate standing waves. A plurality of antennas arranged at a distance from each other, a switching unit that periodically switches the antennas in a fixed station, and a transponding card that receives a transmission signal from the antenna, Depending on the position of the antenna that is switched by the switching main stage, the combined reception input level of the direct wave from the antenna and the reflected wave from the wall of the room, which is received by the transponding card, is increased, and the point where the transponding card cannot communicate is determined. It is designed to be reduced.

(Operation) According to the present invention, in a radio communication system in a narrow space using a TRC, a plurality of antennas provided in a fixed portion of a room and spaced apart from each other, and the antennas are cycled in a fixed station. And a direct wave from the antenna received by the transponding card depending on the position of the antenna switched by the switching means, and a room. The combined input level with the reflected wave from the wall of the device is increased, and the number of incommunicable points due to the transponding card is reduced.

Therefore, it is possible to greatly reduce the probability that the transponding card in the room cannot communicate for a long time.

Moreover, since it is only necessary to add a simple antenna switch and antenna to the base station and there is no need to change the configuration of the TRC, it is technically easy to implement and economically advantageous. (Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a wireless communication system in a narrow space showing an embodiment of the present invention. FIG. 1 (a) is a block diagram thereof and FIG. 1 (b) is a case where ANT switching is not performed. FIG. 1 (c) is a diagram showing a reception situation, and FIG. 1 (c) is a diagram showing a reception situation by the wireless communication system of the present invention.

In the figure, 3 is TRC, 21 is TRX, 22-1, 22-2 is ANT, 23 is an antenna switch, 24 is a processing device for processing and controlling signals,
25 is a room such as an intelligent building forming a narrow space, and 26 is a wall of the room.

In this figure, the antenna switch 23 operates for each polling in accordance with the polling cycle from the processing device 24, and the ANT22
-1 and 22-2 alternate. Then, as shown in Fig. 1 (b), the reception input level of TRC3 is AN
Even if communication is very low when T22-1 is used and communication is impossible, switching to ANT22-2 placed at a distance d and using ANT22-2 results in a standing wave state. Since it changes, as shown in FIG. 1 (c),
Communication becomes possible.

As described above, in the wireless communication system in the narrow space using the TRC, the unreceivable points can be reduced. The structure therefor is simple and economical. That is, it is only necessary to add a simple antenna switch and antenna to the base station, and TRC does not need to change its configuration. In particular, this is because the communication function is built into the TRC that has a light, thin, short, and small shape (see Fig. 3).
Although adding a function to C is not a good idea from a technical point of view, according to the present invention, it is not necessary to make any modification to TRC, and this point can be solved skillfully.

The present invention is not limited to the above embodiment,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described in detail above, according to the present invention, depending on the position of the antenna switched by the switching means, the direct wave from the antenna and the reflected wave from the wall of the room received by the transponding card are detected. TRC of the point in the room because it is possible to increase the combined reception input level of the
It is possible to greatly reduce the probability of being unable to communicate for a long time.

In addition, since it is only necessary to add a simple antenna switch and antenna to the base station and there is no need to change the configuration of the TRC, it is technically easy to implement and economically advantageous.

[Brief description of drawings]

FIG. 1 is a block diagram of a wireless communication system in a narrow space showing an embodiment of the present invention, FIG. 2 is a block diagram of a conventional wireless communication system in a narrow space, FIG. 3 is a block diagram of a TRC, and FIG. FIG. 1 is a block diagram of conventional space diversity. 3 ... Transponding card (TRC), 21 ... Fixed station radio (TRX), 22-1, 22-2 ... Antenna (AN
T), 24 ... Processor, 25 ... Room, 26 ... Wall.

Front page continuation (72) Inventor Takashi Shimanuki 8-21-1, Ginza, Chuo-ku, Tokyo Stock company Takenaka Corporation Tokyo Main Store (72) Inventor Masayuki Tokiwa 8-21-1, Ginza, Chuo-ku, Tokyo Stocks Takenaka Corporation Tokyo Main Store (72) Inventor Takashi Moro 8-21-1, Ginza, Chuo-ku, Tokyo Stock Company Takenaka Corporation Tokyo Main Store (56) Reference JP-A-51-68713 (JP, A) ) JP-A-61-147624 (JP, A)

Claims (1)

[Claims] 1. In a wireless communication system in a narrow space in which radio waves in a room are apt to generate standing waves, a plurality of (a) are provided at a fixed portion of the room and are spaced apart from each other. An antenna; (b) switching means for periodically switching the antenna at a fixed station; (c) a transponding card for receiving a transmission signal from the antenna; and (e) switching by the switching means. Depending on the position of the antenna to be received, the combined reception input level of the direct wave from the antenna and the reflected wave from the wall of the room, which is received by the transponding card, is increased, and the number of incommunicable points by the transponding card is reduced. A wireless communication system in a narrow space.