JP2767641B2 - Multi-frequency simultaneous wireless communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to production of a program in a studio or a hall of a broadcasting station, stage progress in a theater or the like, or a factory,
The present invention relates to a low power multi-frequency simultaneous wireless communication device used for business communication in an event hall or the like.

(Prior Art) FIG. 2 is a diagram showing such a conventional multi-frequency simultaneous radio communication device. 1 is a receiver of the base station B, 2 is a transmission controller of the base station, and 3 and 4 are antennas.
The receiver 1 is connected to antennas 3 and 4, and the audio system is connected to a transmission controller 2. 5 to 8 are base stations B
The slave unit 9 is mounted on the operator with the headset. Reference numerals 10 and 11 denote transmitters of the base station B, which are connected to the transmission controller 2. With such a configuration, the slave units 5 to 8
A call between base stations or a call between slave units via a base station is made possible.

FIG. 3 is a diagram for explaining a communication procedure in the multi-frequency simultaneous radio communication apparatus as described above. FIG. 3 (a) is a flowchart of the procedure, and FIG. 3 (b) is an assignment of a channel frequency to be set in the slave unit. 6 is a channel table showing an example of the above.

In FIG. 2, for example, when the slave unit 5 calls the base station B from the call waiting state, the slave unit 5 first depresses the talk switch (FIG. 3 (a), S (step) 1), and becomes empty. An empty channel search is performed to find a channel that is present (S2). In the empty channel search, a cyclic search is performed for 18 frequencies in the band allocated under the Radio Law (however, the current), but when an empty channel is detected (S3), the system is determined. The called station C is called using the called channel Cch, and if there is a response (S4), the use of the frequency of the detected empty channel is specified (S5). As a result, the base station B of the called station performs carrier sense reception at the specified channel frequency (S6).
If it is confirmed that the designated frequency is not used, transmission / reception between the base station B and the handset 5 is started by the designated channel frequency (S7). The other slave units 6 to 8 also sequentially or simultaneously search for an empty channel to set a communication channel as described above, and start simultaneous mutual communication between the four slave units.

As described above, even in the conventional multi-frequency simultaneous radio communication device, a business call can be made by ignoring the beat interference generated when the distance between the use place of the slave units and the distance from the base station antenna is almost the same. .

(Problems to be Solved by the Invention) However, since the conventional multi-frequency simultaneous radio communication device as described above searches for an empty channel by a cyclic search, for example, the used channel frequency of the slave units 5, 6, and 7 is It may be set to almost equally spaced frequencies,
At this time, a frequency relationship that causes a third-order distortion occurs, and the slave unit 5
And 6 are close to the antenna of the base station and when the antenna input becomes excessive, the base station B receiving the transmission channel of the handset 7
Has a problem that third-order distortion is caused to cause undesired beat interference.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multi-frequency simultaneous radio communication device capable of solving the above-described problems and eliminating beat interference due to third-order distortion without restricting a moving range of a slave unit.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a base station and a plurality of slave units capable of transmitting and receiving only between the base station and a communication area of the base station. In a low power multi-frequency simultaneous radio communication device capable of simultaneous multi-frequency communication, a plurality of frequencies specified by the Radio Law used in the low frequency multi-frequency simultaneous radio communication device are grouped into a group of frequencies that do not generate third-order distortion. And a group consisting of remaining frequency groups that do not belong to the plurality of groups, and the plurality of slaves do not mutually generate third-order distortion in searching for empty channels for communication. This is accomplished by searching for frequencies in the plurality of groups of interest and setting up an empty channel for talking.

(Operation) According to the present invention, a frequency at which four slave units simultaneously talk in the same area is selected in advance from a frequency group in which there is no fear that tertiary distortion will occur, so that tertiary distortion does not occur. Therefore, since no beat interference occurs, it is possible to make a good call regardless of the communication distance between the slave units and the close distance to the base station antenna. Also, since the plurality of frequency groups are independent groups, if an empty channel of one slave is set, the frequency of the group to which the empty channel of the slave belongs is set to the other slave. It is possible to reduce the set time for the vacant channels of the second and subsequent slave units.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1A shows an apparatus applied to the present invention, which is exactly the same as the configuration shown in FIG.

FIG. 1 (b) is a diagram of a channel table for explaining frequency groups set in the present invention.

The present invention is 18 waves that are stipulated by the Radio Law (However, current) relationship does not cause third-order distortion of the channel frequency f _c of 4
It is divided into four groups of waves, 1G to 4G, and one group of the remaining two waves, 5G.

Next, the operation will be described. When the slave unit 5 calls the base station, a talk channel is set by pressing the talk switch in the same manner as in the above-described conventional example. Here, a channel frequency f _c 1 in 1G in FIG. 1 (b) is set.

Further, the other slave units 6, 7, and 8 sequentially or simultaneously search for an empty channel in the group to which the communication channel set to the slave unit 5 belongs and set the use frequency.
8 are set to four waves in the same frequency group, and.

FIG. 1 (b) left is an explanatory view showing an example of a channel set to a slave unit in a call group, where 1G is selected in a call area of a certain base station indicated by a circle and is within the call area. the four child machine _{f c 1, f c 3,} f c 6, f c 12 is set. Also, 2G in the call area of other base stations
There are _{selected, f c 2, f c 4} , f c 7, f c 13 is set to four child machine. Here, 1G base station and 4 slave units, and 2G
, The base station and the four slave units constitute independent transmission / reception systems. That is, the slaves in the same group can transmit and receive only in the communication area with base stations in the same group, and do not transmit and receive with other base stations. For example, if a handset in 1G is used at a position close to a call area in 1G and a call area in 2G, this handset can transmit and receive to and from a base station in 1G, but a base station in 2G You cannot send and receive to and from the station.

As described above, according to the present invention, a call is made using four waves in a set frequency group.
Even if the next distortion occurs, there is no mutual effect within the call group, so even if they are close to each other in the same area or the distance to the base station is short, there is no fear that beat interference will occur. Between multiple groups,
Alternatively, there is an advantage that interference between groups hardly occurs even when using multiple areas.

(Effects of the Invention) As described above, the present invention eliminates the occurrence of interference that occurs during simultaneous reception in a narrow communication area, and further enables the base station receiver to reduce the reception sensitivity without considering third-order distortion. Can be expanded, so the call area can be expanded,
In the case of simultaneous transmission in a narrower call area,
There is an effect that the time for searching for an empty channel for the second and subsequent units can be reduced.

[Brief description of the drawings]

FIG. 1 (a) is a diagram of an embodiment of a multi-frequency simultaneous radio communication device of the present invention, FIG. 1 (b) is a diagram for explaining frequency selection in one embodiment of the present invention, and FIG. FIG. 3 is a diagram showing a mode of the wireless communication apparatus, and FIG. 1 ... Receiver, 2 ... Transmission controller, 3,4 ... Antenna,
5, 6, 7, 8 ... slave unit, 9 ... headset, 10, 11 ... transmitter.

Claims (1)

(57) [Claims] 1. A low-power multi-frequency simultaneous communication system having a base station and a plurality of slave units capable of transmitting and receiving only within the communication area of the base station and the base station. In a wireless communication device, a plurality of frequencies stipulated by the Radio Law
Dividing into a plurality of groups each including a frequency group that does not generate a third-order distortion as one group and a group including remaining frequency groups that do not belong to the plurality of groups, A multi-frequency simultaneous radio communication apparatus, wherein a search is made for an empty channel by searching for frequencies in the plurality of groups which do not cause a third-order distortion to each other, and an empty channel is set for communication. .