JP6643933B2 - Intercom system - Google Patents

Description

  The present invention relates to an intercom system capable of receiving a call from an intercom slave unit and responding with a portable wireless master unit in addition to the intercom master unit.

There are cordless telephones and intercom devices that communicate using signals based on the DECT standard (DECT communication). DECT communication can be expected to have clearer communication without congestion than conventional cordless devices using the 2.4 GHz band, and since the communication speed is high, image transmission can be performed more smoothly than before. Equipment is expected to spread further.
On the other hand, in DECT communication, there are originally five usable frequencies, but when used in an environment in which a self-owned PHS control signal exceeds a certain level, it is limited to two channels to protect the PHS signal. Was done. Also, in an environment where a DECT signal is detected beyond a certain level, there is a carrier sense that the slot cannot be used.
For this reason, for example, in Patent Document 1, a function of identifying a self-owned PHS control signal is provided instead of determination based on the presence or absence of a radio wave, thereby preventing a decrease in the number of channels due to slot timing adjustment or the like and improving frequency use efficiency.

JP 2011-077986 A

  As described above, DECT communication is subject to various restrictions. Therefore, it is necessary to devise measures to prevent a decrease in the number of channels, as in Patent Document 1, but if there is a device that performs DECT communication in the vicinity, In addition to the protection of PHS signals, the problem of interference with those devices also arises. In particular, in an environment where adjacent dwelling units such as an apartment house are close to each other and intercom equipment of the same model is installed in each dwelling unit, radio interference between the intercom master units, that is, DECT communication interference occurs. Measures are needed.

FIG. 3 is a diagram for explaining the occurrence of interference in an apartment house, where R indicates a dwelling unit, 41 indicates an intercom master unit installed in a living room, and 42 indicates a wireless master unit that wirelessly communicates with the intercom master unit. E indicates an area where the intercom master unit 41 can communicate with the wireless master unit 42.
As shown in FIG. 3, in an apartment house, interference is likely to occur between intercom master units of adjacent dwelling units, and interference may occur between upper and lower dwelling units in addition to the left and right.

  In addition, in the intercom system, a camera for imaging a visitor is often provided in the intercom slave unit, in which case the video signal of the camera is also transmitted, and not only a two-way audio signal but also a wireless signal from the intercom master unit. A one-way video signal is also transmitted to the master unit. For this reason, the transmission ratio of the intercom master unit is high, and further measures are required to prevent a decrease in the number of channels.

  Accordingly, the present invention has been made in view of such a problem, and when performing DECT communication between an intercom master device and a wireless master device, it is possible to minimize radio wave interference with surrounding wireless devices and achieve communication. The purpose is to provide an intercom system that can secure the number of channels.

In order to solve the above-mentioned problems, the invention of claim 1 is provided at an entrance of a dwelling unit or at an entrance of an apartment house to call a resident and an intercom slave unit installed in a living room to receive a call from the intercom slave unit. An intercom system having an intercom base unit for answering, wherein the intercom base unit is provided with a radio base unit having a function of responding to a call from an intercom slave unit by performing DECT communication with the intercom base unit. A wireless communication unit for performing DECT communication with the master unit is connected to the wireless communication unit. A plurality of antennas having different polarization planes are connected to the wireless communication unit. The wireless communication unit includes an antenna selection unit that compares the magnitude of the power and selects the antenna with the lowest received power. Using an antenna selection means selects which comprises carrying out communications with the radio base unit.
According to this configuration, since an antenna having a low external radio wave reception level is selected and used for communication with the wireless master device, even when communication is performed with the wireless master device, radio interference with surrounding wireless devices is minimized. , And a state in which communication with the wireless master device is disabled can be reduced. Further, by selecting an antenna having a low reception level, it is possible to minimize the decrease in the number of communication channels, suppress the transmission level itself, and reduce the influence on external wireless devices.

According to a second aspect of the present invention, in the configuration according to the first aspect, when the antenna receives a self-owned PHS control signal, the antenna selecting means selects an antenna having the smallest received power of the self-owned PHS signal. And
According to this configuration, radio interference can be minimized even when a device that uses the self-owned PHS signal is around.

According to a third aspect of the present invention, in the configuration according to the first aspect, when the antenna does not receive the self-owned PHS control signal, the antenna selecting means selects the antenna having the smallest received power of the received DECT signal. And
According to this configuration, even if there is no self-owned PHS signal, the antenna that causes the least interference is used in consideration of other DECT devices, so that the transmission level can be suppressed to the maximum.

According to a fourth aspect of the present invention, in the configuration according to any one of the first to third aspects, the antenna selection unit periodically performs an antenna selection sequence for comparing the magnitudes of the reception powers of the plurality of antennas and uses the antenna selection sequence. The antenna is selected every time.
According to this configuration, since the antenna selection sequence is periodically performed, even when a new wireless device is installed nearby, it can be recognized and dealt with.

  According to the present invention, since an antenna having a low external radio wave reception level is selected and used for communication with the wireless master device, even when communication is performed with the wireless master device, radio interference with surrounding wireless devices is minimized , And a state in which communication with the wireless master device is disabled can be reduced. Further, by selecting an antenna having a low reception level, it is possible to minimize the decrease in the number of channels, suppress the transmission level itself, and reduce the influence on external wireless devices.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows an example of the intercom system which concerns on this invention, and shows only a main part with a circuit block diagram only in an intercom master. It is a flowchart which shows the flow of an antenna selection sequence. It is explanatory drawing of the radio wave interference which generate | occur | produces in an apartment house intercom system.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an example of an intercom system according to the present invention, in which only a main part of an intercom master unit is shown in a circuit block diagram. In FIG. 1, reference numeral 1 denotes an intercom slave unit installed at the entrance of a dwelling unit or an entrance of an apartment complex to call a resident, and 2 denotes an intercom master unit installed in a dwelling unit to respond to a call from the intercom slave unit 1. Reference numeral 3 denotes a wireless master unit that wirelessly communicates with the intercom master unit 2 to notify a call from the intercom slave unit 1 and that a resident can carry while answering.
The intercom slave 1 and the intercom master 2 are connected by a transmission line L1, and the radio master 3 performs radio communication with the interphone master 2, particularly DECT communication.

The intercom master unit communicates with a microphone 21 and a speaker 22 for talking as shown in FIG. 1, a monitor 23 for displaying an image captured by a camera (not shown) provided in the intercom slave unit 1, and a wireless master unit 3. (The first antenna 24a, the second antenna 24b) 24, the antenna switching unit 25 that switches between the two antennas 24a and 24b, the wireless communication unit 26 that performs the DECT communication, the reception data and setting of the PHS signal and the DECT signal , A base unit CPU 28 for controlling the selection of the antenna 24 and controlling the intercom base unit 2, a base unit communication IF 29 for communicating with the intercom slave unit 1, and the like.
The first antenna 24a and the second antenna 24b are arranged so as to be orthogonal to each other. Here, the first antenna 24a is arranged vertically to transmit and receive vertically polarized waves, and the second antenna 24b is arranged horizontally so as to be horizontal. It is configured to transmit and receive polarized waves. Reference numeral 3a denotes a communication antenna of the wireless master device 3 that performs wireless communication with the intercom master device 2.

The intercom system configured as described above operates as follows. However, the call from the intercom slave unit 1, the call notification operation by the intercom master unit 2 or the wireless master unit 3 that has received the call, and the subsequent answering call operation are the same as those in the related art, and thus the description is omitted. The antenna selection operation 2 will be specifically described.
The antenna selection sequence for selecting one of the two antennas 24a and 24b is performed only when the intercom master unit 2 is in a standby state, and is executed under the control of the master unit CPU. The operation is stopped when an interrupt such as a call occurs.

  The antenna selection sequence is performed every fixed time T (for example, every hour). When the predetermined time T has elapsed (Yes in S1), it is first determined whether there is a self-owned PHS control signal. First, it is determined whether the first antenna 24a is receiving a self-owned PHS control signal (S3), and if it is, the RSSI is obtained (S4). Next, it is determined whether the second antenna 24b is receiving the self-owned PHS control signal (S6). If the second antenna 24b is receiving the self-owned PHS control signal, the RSSI is acquired (S7).

In this way, the RSSI values are obtained from both the first antenna 24a and the second antenna 24b, the RSSI value levels are compared (S8), and the smaller antenna 24 is fixed as the antenna 24 used for communication with the radio cell station 3. (S9, S10).
If the PHS control signal is not received by the first antenna 24a (No in S3) and is received only by the second antenna 24b (Yes in S5), the PHS control signal is fixed to the first antenna 24a (S10), and only the first antenna 24a is received. If a PHS control signal has been received (No in S6), it is fixed to the second antenna 24b (S9). As a result, the weaker received radio wave is selected and used for communication with the wireless master device 3.

  If both the first and second antennas 24a and 24b do not receive the self-owned PHS control signal (No in S5), then the antenna 24 is selected based on the received signal of the DECT signal. First, the RSSI of the DECT signal received by the first antenna 24a is obtained (S11), and the maximum value among them is used as a criterion value (S12). Next, the RSSI of the DECT signal received by the second antenna 24b is acquired (S13), and the maximum value among the RSSIs is used as a judgment reference value (S14). In the case of the DECT signal, since the reception of a plurality of signals is considered, the RSSI having the maximum value among the received signals is used as a reference.

  The maximum values of the RSSIs thus obtained are compared with each other (S15). If the RSSI of the first antenna 24a is large, the RSSI is fixed to the second antenna 24b (S16). It is fixed (S17). When the antenna 24 is selected in this way, the timer is reset (S18), and the control returns to the standby state. After a lapse of a predetermined time T, the control is restarted from the step of S1.

As described above, since the antenna 24 having a low external radio wave reception level is selected and used for communication with the wireless master device 3, even if communication with the wireless master device 3 is performed, interference with surrounding wireless devices is minimized. Limit, and a state in which communication with the wireless master device 3 is disabled can be reduced. Further, by selecting the antenna 24 having a low reception level, the decrease in the number of communication channels can be minimized, the transmission level itself can be suppressed, and the influence on external wireless devices can be reduced.
Further, since the antenna 24 to be used is selected with priority given to the reception state of the private PHS signal, radio interference can be minimized even when a device using the private PHS signal is around.
Furthermore, even if there is no self-owned PHS signal, the antenna 24 that causes the least interference is used in consideration of other DECT communication devices, so that the transmission level can be suppressed to the maximum. Then, since the antenna selection sequence is periodically performed, even when a new wireless device is installed nearby, it can be recognized and dealt with.

In the above-described embodiment, the intercom master unit 2 is provided with the two antennas 24 of the first antenna 24a for transmitting and receiving the vertically polarized wave and the second antenna 24b for transmitting and receiving the horizontally polarized wave. Two or more antennas may be provided, or more antennas may be connected and either one may be selected.
In addition, the waiting time T for starting the antenna selection sequence is set to a fixed time of, for example, one hour here, but it may be changed each time and a random back-off time may be added, and a plurality of systems may simultaneously execute the antenna selection sequence. Can be avoided.

  1. Intercom slave unit, 2. Interphone master unit, 3. Wireless master unit, 24 antenna, 25 antenna switching unit, 26 wireless communication unit, 28 master CPU (antenna selection means ).

Claims (4)

An intercom system including an intercom slave unit installed at the entrance of a dwelling unit or an apartment complex for calling a resident, and an intercom master unit installed in a living room for receiving and answering calls from the intercom slave unit. hand,
A wireless base unit having a function of responding to a call from the intercom slave unit by performing DECT communication with the intercom master unit, and the intercom master unit includes a wireless communication unit that performs DECT communication with the wireless master unit. Have
The wireless communication unit is connected with a plurality of antennas having different polarization planes of the main polarization,
The intercom master unit has an antenna selection unit that compares the magnitude of the received power of each of the plurality of antennas and selects an antenna with the smallest received power,
The intercom system, wherein the wireless communication unit performs communication with the wireless master device using an antenna selected by the antenna selection unit.   2. The intercom system according to claim 1, wherein said antenna selecting means selects an antenna having the smallest received power of the private PHS signal when said antenna receives a private PHS control signal.   2. The intercom system according to claim 1, wherein the antenna selecting means selects an antenna having the smallest received power of the received DECT signal when the antenna does not receive the self-owned PHS control signal.   4. The antenna according to claim 1, wherein the antenna selection unit periodically performs an antenna selection sequence for comparing the magnitude of received power of each of the plurality of antennas, and selects an antenna to be used each time. 5. The intercom system according to any one of the above.

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