JPH0613931A - Mobile communication system - Google Patents

Abstract

PURPOSE:To reduce loss in an RF section without the use of a filter by the duplex communication system by providing a voice detector so as to control an RF switch automatically. CONSTITUTION:The system is provided with a voice detector (V.DET) 9 detecting a coded signal from a voice coder 7, and when a speech head of a voice signal is detected by a control signal of the V.DET 9, a switch of an RF switch 2 is switched to the position of a transmission section, and the switch of the RF switch 2 is switched to the position of a reception section at the detection of no voice signal. That is, the V.DET 9 inputs a voice detection signal to switch the RF switch 2 to the position of an HPA 3 by using a relevant control signal. Since the V.DET 9 inputs no voice detection signal for a non-voice period, the control signal is stopped, the RF switch 2 is turned to the position of an LNA 14 side and the state is restored to a reception signal wait state. Thus, the instantaneous operation of the device is in accordance with the simplex communication system, while the operating mode of the talker adopts the duplex communication system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system, and more particularly to a mobile communication system capable of automatically switching between transmission and reception depending on the presence / absence of a voice signal input to a transmitter.

[0002]

2. Description of the Related Art In the conventional mobile communication system, as shown in FIG. 4, 1 is an antenna, 2 is an RF switch, 3 is a high power amplifier (HPA), 4 is an up converter (U / C), and 5 is a modulator. (MOD), 6 is a transmission baseband processing circuit (T
X BBP), 7 is a voice encoder (V.COD), 8 is a handset (HAND SET), and 10 is a voice decoder (V.COD).
DEC, 11 is a reception baseband processing circuit (RX B
BP), 12 is a demodulator (DEM), 13 is a down converter (D / C), 14 is a low noise amplifier (LNA), 15
Is a push button switch. In this conventional example, while the caller is pressing the push button switch 15, the antenna 1
Is connected to the transmission unit via the RF switch 2, and the transmission voice is transmitted as a radio signal. Push button switch 15
While not pressing, the antenna 1 is connected to the receiving unit via the RF switch 2. It is a well-known press talk or simplex communication system. This method is uncomfortable and annoying because it is necessary to inform the other party by saying "Please" or "Over" when one of the parties finishes talking.

Another conventional example is the Duplex communication system shown in FIG. A duplexer (DPX) is used instead of the RF switch 2 and push button switch 15 of the conventional example.
16 are arranged. That is, the fact that the frequency bands of the transmitter and the receiver are different is used to automatically separate the transmission and reception signals using a filter. Therefore, both parties can talk to each other and can speak in a natural form.

[0004]

In the above-mentioned two types of conventional systems, the Duplex communication system has a natural conversation, but has a drawback that the reception level and the transmission level are lowered due to the passage loss of the filter. In particular, since mobile satellite communication has high transmission power, a large amount of transmission / reception separation is required, which further increases the pass loss of the filter. On the other hand, the simplex communication method has a very small passage loss of the RF switch, but has a drawback that the conversation style is unnatural as described above. SUMMARY OF THE INVENTION An object of the present invention is to provide a mobile communication system which uses a duplex communication system and which does not use a filter and has a small passage loss in the RF section.

[0005]

According to the mobile communication system of the present invention, an antenna for transmitting and receiving radio signals is connected to a high power amplifier side or a low noise amplifier side by switching the antenna according to a control signal supplied from the outside. An RF switch, a transmitter for converting a voice signal into an electric signal by a transmitter, a modulator for converting an analog signal of the transmitter into a prescribed code format and digitally modulating it, and an output of the modulator by an up converter. A low-power amplifier configured to include a high-power amplifier that amplifies the RF signal converted into a frequency to a prescribed power value, and a receiving unit that amplifies the received signal supplied from the RF switch A demodulator that reproduces an IF signal, which has been frequency-converted to a specified IF frequency band by a converter, into an electric audio signal, and a converter that converts this electric audio signal into an acoustic audio signal. In a mobile communication system configured with a receiver, a voice detector for detecting the presence or absence of a coded voice signal at the modulator input is provided, and the RF switch is connected to the high power amplifier side during the voice signal presence time. It is characterized in that the audio signal is connected to the low noise amplifier side when there is no predetermined time.

[0006]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of signal operation of each part of the present embodiment. 1, the same reference numerals as those in the conventional example shown in FIGS. 4 and 5 have the same configurations and functions. That is, in the embodiment of FIG. 1, a voice detector 9 for detecting a coded signal of the voice encoder 7 is provided, and when the control signal of this voice detector 9, that is, the head of voice is detected, the switch of the RF switch 2 is transmitted. Switched to the department and connected. Therefore, when there is no sound, the RF switch 2 is switched and connected to the receiving section.

Next, the operation of this embodiment will be described with reference to FIGS. An analog voice signal is intermittently input from a voice transmitter of the handset 8 to a voiced region and an unvoiced region as shown in FIG. The voice encoder 7 detects the head of the voiced area and outputs a detection signal during the voiced area as shown in FIG. 2B, and V.COD7, TXBBP6
After being quantized and coded by the voice, it is modulated into a transmission signal of MOD5, and the transmission signal shown in FIG.
Sent from A3. On the other hand, the V / DET 9 inputs the voice detection signal of FIG. 2B and switches the RF switch 2 to the HPA 3 side by the corresponding control signal to connect it. On the other hand, in the unvoiced area, since the V.DET 9 does not input the voice detection signal, the control signal is stopped, the RF switch 2 is switched and connected to the LNA 14 side, and returns to the state of waiting for a reception signal. Therefore, V-DET9 smooths the encoded continuous pulse signal, or the holding circuit causes a slight loss of the audio signal to cause RF.
The switch 2 is designed so that it does not change from transmitting to receiving.

The feature of this embodiment is that the instantaneous operation of the apparatus is a simplex communication system, but the manner of use by the caller is a Duplex communication system. In a typical conversation, one person speaks and the other listens. In natural conversation, when the person who was speaking has finished speaking, either the other person starts speaking or the listener interrupts until then. When both people speak at the same time, no conversation is established, but in the conventional simplex method, the words "over" or "please" are used to notify the end of the way of talking in order to avoid such a state. It was impossible for anyone to interrupt, and the naturalness of the conversation was impaired. In order to improve this point, the present invention enables the listener to interrupt at any time to realize a natural conversation. There is always silence in human speech. During this time, the device is in a receiving state and can hear the voice of the other party. Since the device is momentarily in either transmitting or receiving state, the disconnection of the talk is unavoidable. Therefore, to interrupt the other party while talking, use meaningless words such as "Hello" and "Hello". In mobile communications, shadows occur frequently due to the surrounding environment,
In the conventional simplex method, when the above "please" is heard, both callers become listeners, and the process of restarting the conversation again is troublesome. You can start

The present invention has an important point in that transmission / reception switching of a device is performed at high speed by detecting a voice signal. In order to realize it, there is a circuit configuration as shown in FIG. The RF switch 2A is a switch for turning on / off the received signal, and the control signal from the voice detector 9 controls the connection between the antenna 1 and the receiving section and simultaneously turns on / off the power supply of the transmitting section. Since the transmission section is disconnected during reception, there is no problem of noise sneak from the transmission section to the reception section, and the reception section is disconnected during transmission.
There is no problem such as destruction of A14.

As described above, the connection loss to the antenna can be made extremely small, the required gain of the antenna can be lowered, and the antenna can be miniaturized. At the same time, HPA
Not only does it require a small instantaneous power value, but in a normal human conversation, the rate of silent time is only about 1/3, so that the average power can be significantly reduced.

[0011]

As described above, according to the present invention, the following effects can be obtained by automatically controlling the RF switch with the voice detector.

(1) It is possible to perform voice communication in a duplex operation substantially by using a circuit that performs a simplex operation.

(2) The connection loss between the RF section and the antenna can be reduced, and the antenna can be downsized.

(3) The power consumption of the transmission unit can be greatly reduced by cutting off the power supply of the transmission unit while the transmission sound is silent.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the present embodiment.

FIG. 3 is a block diagram of a main part of an application example of an embodiment of the present invention.

FIG. 4 is a block diagram of a conventional example.

FIG. 5 is a block diagram of another conventional example.

[Explanation of symbols]

 1 Antenna 2 RF Switch 3 High Power Amplifier (HPA) 4 Up Converter (U / C) 5 Modulator (MOD) 6 Transmission Baseband Processing Circuit (TX BBP) 7 Voice Coder (V / COD) 8 Handset (HAND) SET 9 Voice detector (V / DET) 10 Voice decoder (V / DEC) 11 Reception baseband processing circuit (RX / BBP) 12 Demodulator (DEM) 13 Down converter (D / C) 14 Low noise amplifier ( LNA)

Claims (2)

[Claims] 1. An antenna for transmitting / receiving a radio signal, an RF switch for connecting the antenna to a high power amplifier side or a low noise amplifier side by a control signal supplied from the outside, and an RF switch for connecting the antenna to a voice signal. A transmitter for converting into a signal, a modulator for converting an analog signal of the transmitter into a specified code format and digitally modulating it, and an RF signal obtained by converting the output of the modulator into an RF frequency by an up-converter with a specified power value. And a low-noise amplifier for amplifying the received signal supplied from the RF switch, and the output of the low-noise amplifier is frequency-converted into a specified IF frequency band by a down converter. Mobile communication system composed of a demodulator for reproducing an IF signal into an electric voice signal and a receiver for converting the electric voice signal into an acoustic voice signal In the case where a voice signal is detected for detecting the presence or absence of a coded voice signal at the modulator input, the time when the voice signal is present is such that when the RF switch is connected to the high power amplifier side and the voice signal does not have a predetermined time. A mobile communication system characterized in that the mobile communication system is connected to the low noise amplifier side. 2. The high power amplifier is a high power amplifier with power on / off having a function of turning on / off a power supplied to the amplifier according to a control signal from an attached terminal, and the RF switch is an input part of the low noise amplifier. The high power amplifier output unit with power ON / OFF connected to the antenna is directly connected to the antenna, and the control signal of the voice detector controls a terminal attached to the high power amplifier to turn on the power (or The mobile communication system according to claim 1, wherein the RF switch is turned off and the RF switch is turned off (or on).