JP3090215B2 - Transmission / reception shared circuit for mobile full-duplex wireless equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] Regarding a transmission / reception shared circuit of a mobile full-duplex wireless device, it can be used when performing full-duplex wireless communication between mobile stations using two waves whose bands are close to each other. The purpose of the present invention is to provide a transmission / reception shared circuit that makes effective use of a simple band and that does not have an adverse effect due to the transmission wave of its own station or the intrusion of a transmission wave of another station that is not the communication partner. Separating means for supplying the signal to the antenna and supplying the signal from the antenna to the receiver; at least four kinds of band-pass filter means having a pass band set so as to divide each of the usable two wave bands into at least two parts;
Switch means for passing a signal from the transmitter to the antenna and a signal from the antenna to the receiver, respectively, through any of the band-pass filter means, and switching so that the frequency difference between the respective pass bands is constant. And configure.

[Industrial applications]

The present invention relates to a transmission / reception shared circuit suitable for a mobile full-duplex wireless device performing bidirectional mobile wireless communication using two bands having different frequencies.

In recent years, the needs of wireless systems used for mobile communication and the like have changed from conventional half-duplex (simplex) communication to full-duplex (duplex) communication. Also,
Regarding the use of the frequency, there is a demand for a device configuration in which some channels can be switched and used, compared to the conventional device configuration using only a specific channel.

[Conventional technology]

The configuration shown in FIG. 6 can be considered as a transmission / reception shared circuit for connecting a transmitter and a receiver by sharing one antenna.

A signal from the transmitter 60 is supplied to a circulator 120 via a bandpass filter 160 and a circulator 200 for impedance adjustment. The circulator 120 supplies a transmission signal from the circulator 200 to the antenna and supplies a reception signal from the antenna to the circulator 122. The circulator 122 supplies the received signal to the bandpass filter 161 and supplies unnecessary radio waves repelled by the bandpass filter 161 to the dummy load 124 for consumption.
The signal passed through the bandpass filter 161 is supplied to the receiver 70 via the circulator 201 for impedance adjustment.

When channel change is not required as in the communication between fixed stations, the pass bandwidths of the band filters 160 and 161 are set to be narrow around the frequencies of the transmission channel and the reception channel, respectively. Interference due to wave wraparound and interference due to received waves of other channels are avoided.

However, in the case of communication between mobile stations, a band in which the channels of the reception wave and the transmission wave can be used is used in case that another station using the same band as the frequency band of the reception wave as a transmission wave approaches and interferes. It is necessary to be able to be arbitrarily switchable within. In this case, if this is to be realized by the circuit having the configuration shown in FIG. 6, the BPF 160 shown in FIG.
And 161 bands into two usable bandwidths,
It is possible to arbitrarily switch the channels used by the transmitter and the receiver by switching the carrier frequency in the transmitter 60 and switching the tuning frequency of the receiver 70 within these ranges.

In that case, as indicated by f ₁ and f ₁ 'in the figure, as the difference in frequency between the transmitted and received waves is always constant, i.e., the relative frequency of the received wave in each band and the transmission wave It is common to set the same position.

[Problems to be solved by the invention]

In the above-described configuration, when it is unavoidable that the usable frequency bands are close to each other between the transmission wave and the reception wave, the transmission frequency f ₁ ′ is set closer to the reception band as shown in the drawing. And the transmission wave of the own station goes around to the receiving side because it is close to the pass band of the bandpass filter 161 and the bandpass filter
A problem arises in that it enters the receiver 70 through 161 and adversely affects the amplifier.

In addition, as a result of the movement, approaching another station that is not the communication partner using the same band as the reception frequency of the own station, the transmitted wave enters the receiver 70 through the band filter 161 and adversely affects the amplifier. There is also the problem of having.

Therefore, it is an object of the present invention to provide two
When performing full-duplex wireless communication between mobile stations using waves, the available band is effectively used, and the transmitted wave of the own station is wrapped around, or the transmitted wave of another station that is not the communication partner is transmitted. An object of the present invention is to provide a transmission / reception shared circuit which is free from an adverse effect of intrusion.

[Means for solving the problem]

FIG. 1 is a diagram showing a principle configuration of a transmission / reception shared circuit suitable for a mobile full-duplex wireless device according to the present invention.

The separating means 12 supplies a signal from the transmitter to the antenna and supplies a signal from the antenna to the receiver. The bandpass filter means 16 are at least four kinds of bandpass filter means whose passbands are set so as to divide at least two usable wave bands. The switch means 14 allows a signal from the transmitter to the antenna and a signal from the antenna to the receiver to pass through any one of the band-pass filter means 16 so that the difference in frequency between the respective pass bands is constant. Switching.

[Action]

As shown in FIG. 2, the higher frequency band (high group)
It is divided into two regions of Ha and Hb (Ha <Hb), and the lower frequency band (low group) is divided into two regions of La and Lb (La <Lb). Band. In this case, for example, when Ha is selected for transmission, La sufficiently distant from it is selected for reception, so that its own transmitted wave does not go around. Also, when there is a risk of being affected by transmission waves from other stations, La or Lb,
To Lb or La and Ha or Hb, to Hb
Alternatively, it can be avoided by switching to Ha or swapping the high and low groups.

〔Example〕

FIG. 3 is a diagram showing a first embodiment of the transmission / reception shared circuit of the present invention. This shared transmission / reception circuit is used for a mobile full-duplex wireless device.

The circulators 120 and 122 and the dummy load 124
It is the same as that described in the figure. Circulator 202-2
09 is used in pairs with the bandpass filters 162 to 169 to adjust the impedance. Band filters 162,166
Has the passband of FIG. 2 La, 163,167 is Lb, 164,168 is
Ha, 165, 169 have a pass band of Hb.

The changeover switches 140 and 142 perform manual switching so that the transmission signal from the transmitter 60 passes through any of the bandpass filters 162 to 165 and is supplied to the circulator 120. The changeover switches 141 and 143 work in conjunction with the changeover switches 140 and 142 to allow the reception signal from the circulator 122 to pass through any of the bandpass filters 166 to 169, and to pass the passband of the transmission-side filter and the passage of the reception-side filter. Switching is performed so that the difference in frequency from the band is always constant.

In the configuration shown in FIG. 3, both the high group and the low group can be used on both the transmitting side and the receiving side.

 FIG. 4 is a diagram showing a second embodiment of the present invention.

The changeover switches 144 and 146 perform manual changeover so that the transmission signal from the transmitter 60 passes through one of the bandpass filters 162 and 163 and is supplied to the circulator 120. The changeover switches 145 and 147 work in conjunction with the changeover switches 144 and 146 to pass the reception signal from the circulator 122 to one of the bandpass filters 168 and 169, and to change the passband of the transmission-side filter and the passband of the reception-side filter. Are switched so that the difference between the frequencies is always constant.

In the configuration shown in FIG. 4, the receiving side selects a filter from any of the high groups, and the transmitting side selects a filter from any of the low groups. Therefore, if the communication partner also has the same configuration, it is necessary to adopt a configuration in which the receiving side selects from the high group and the transmitting side selects from the low group.

 FIG. 5 is a diagram showing a third embodiment of the present invention.

Switches 148 and 153 are transfer type switches. When a path from the transmitter 60 to the switch 149 is selected by the switch 148, a path from the circulator 122 to the switch 150 is formed at the same time. Transmitter
When the path from 60 to the switch 150 is selected, a path from the circulator 122 to the switch 149 is formed at the same time. The switch 153 is linked to the switch 148. When the switch 148 selects a path from the transmitter 60 to the switch 149, it selects a path from the switch 151 to the circulator 120, and at the same time, a path from the switch 152 to the receiver 70. To form Switch 148 switches from transmitter 60 to switch 150
When the path to the circulator 120 is selected, the path from the switch 152 to the circulator 120 is selected, and at the same time, the path from the switch 151 to the receiver 70 is formed.

Switch 149 and switch 151 are linked, and switch 149
162 or a bandpass filter passing between
Select one of 163. Switch 150 and switch 152
Work together with each other, and also work with switch 149,
When the band filter 162 is selected, the band filter 164 is selected. When the band filter 163 is selected, the band filter 1 is selected.
Select 65.

In the example shown in FIG. 5, any of the high group and the low group can be selected on both the transmitting side and the receiving side as in the example shown in FIG. 3, but in the example shown in FIG. While four band filters are required, four are sufficient.

In the examples described above, the case where the high group and the low group are each divided into two has been described. This is enough to prevent the own transmitted wave from wrapping around.
The greater the division, the wider the range of choices for switching to prevent interference with other stations.

〔The invention's effect〕

As described above, according to the present invention, in a mobile full-duplex wireless device, the entire range of the usable area can be effectively used, and the transmitted wave of the own station can be wrapped around, or the There is no adverse effect due to the intrusion of the transmission wave. Also,
By dividing the band, the bandwidth of each band filter is narrowed, whereby the characteristics of the filter can be made steeper, and the effect of further improving the interference rejection characteristic can be obtained.

[Brief description of the drawings]

1 is a diagram showing the principle of the present invention, FIG. 2 is a diagram for explaining the operation of the circuit according to the present invention, FIG. 3 is a diagram showing a first embodiment of the present invention, and FIG. FIG. 5 is a diagram showing a second embodiment of the present invention, FIG. 5 is a diagram showing a third embodiment of the present invention, FIG. 6 is a diagram showing a conventional transmission / reception shared circuit, FIG. The figure for explaining operation | movement. In the figure, 140 to 153 switches, 160 to 169 band filters, 12
0,122,202-209 ... Circulator.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-138849 (JP, U) JP-A-2-93850 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 1/48 H04B 1/50

Claims (1)

(57) [Claims] 1. Separating means for supplying a signal from a transmitter to an antenna and supplying a signal from the antenna to a receiver.
And at least four kinds of band-pass filter means (16) whose passbands are set so as to divide each usable two-wave band into at least two parts: a signal from the transmitter to the antenna and a signal from the antenna to the receiver Switch means (14) for passing a signal to each of the band-pass filter means (16) and switching so that the frequency difference between the respective pass-bands is constant. Transmission / reception shared circuit for mobile full-duplex wireless equipment.