JP2606595B2 - Digital wireless communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a plurality of wireless zones in a small area, and includes a TDMA / TDD (Time Divisio
n Multiple Access: Time Division Duplex
(plex: time division duplex) Used for time division multiplex communication by the method. The present invention relates to a digital wireless communication system capable of reducing power consumption during standby by intermittently supplying power to a wireless device of a mobile station.

[0002]

2. Description of the Related Art Conventionally, in digital radio communication between a base station and a mobile station according to this type of TDMA / TDD system, transmission and reception are alternately time division multiplexed and transmitted and received as shown in FIG. That is, the communication between the mobile station and the base station is performed in a TDD system in which transmission and reception are performed at regular intervals in each time slot to perform communication.
Communication with a plurality of mobile stations is performed by the A digital communication system.

A TDMA / TDD frame used in communication between a base station and a mobile station is configured, for example, as shown at 10 in FIG. 6, and one TDMA / TDD frame has a length of one frame of 5 mS. , And eight slots having a length of 0.625 mS. The first to fourth slots are used as transmission slots of the base station, that is, reception slots of the mobile station. The fifth to eighth slots are used as reception slots of the base station, that is, transmission slots of the mobile station.

When communication is performed between a base station and a mobile station,
One reception slot and one transmission slot are allocated to one mobile station per frame. The voice signal data used for communication between the mobile station and the base station is converted into a PCM (Pulse Code Modulation: Pulse Code Modulation) voice band signal by analog / digital exchange at a transmission rate of 3.
It is compression-encoded into a 2 Kbps ADPCM (Adaptive Differential PCM) signal, processed as packet data, and superimposed on one transmission slot or reception slot.

[0005] In the digital radio communication based on the TDMA / TDD system, in order to actually realize the communication between the base station and the mobile station, the base station and the mobile station are required to keep the same time by using a reference signal with excellent accuracy. It is necessary to have a generation circuit and establish synchronization between the base station and the mobile station. Therefore, a radio frame synchronization signal is transmitted from the base station to the mobile station, and the mobile station establishes synchronization with the base station based on the synchronization signal. This state is shown in FIG.

According to FIG. 7, the mobile station synchronizes itself with the transmission signal (T1) transmitted from the base station, and transmits the mobile station at the reception timing (R1) of the base station. The timing shown in FIG. 7 is for the case where the mobile station is used in a call.

On the other hand, even in a standby state other than during a call, the mobile station needs to synchronize the timing of the radio frame with the base station, so that the mobile station constantly receives the reception timing from the base station intermittently. Thus, the transmission and reception timing of the mobile station is synchronized. This state will be described with reference to FIG.

[0008] According to FIG. 8, the mobile station has 1 TDMA / TD.
Rather than transmitting and receiving every D frame, the mobile station synchronizes the transmission and reception timing by receiving the intermittent synchronization signal T4 sent from the base station. In this case, the mobile station controls the intermittent reception operation in order to extend the life of the battery while the mobile station is in the standby state, and supplies power to the radio unit of the mobile station and each circuit unit of the control unit only during reception. In other vacant timing times, battery saving for shutting off the power supply of the mobile station is performed. The mobile station itself realizes battery saving by shutting off the power supply at times other than the reception timing and preventing unnecessary battery consumption. This state is shown in FIG.

Here, in the mobile station, a timer for controlling ON / OFF of the power supply of the circuit section of the mobile station is set in advance in accordance with the reception timing from the base station, and immediately before receiving a transmission signal from the base station. By setting up the time of the timer, the power supply of the circuit unit of the mobile station is controlled to be ON, and power is supplied to each circuit unit. As described above, when the mobile station is on standby, it is possible to extend the battery by battery saving.
As shown in FIG. 7, since the mobile station always performs transmission and reception at the transmission and reception timing for each frame, battery saving such as the standby state of the mobile station cannot be performed.

As a technique disclosed in the related art, a technique for reducing power consumption in a standby state (Japanese Patent Laid-Open Nos. 4-345330 and 4-70430), and a power supply voltage to be supplied is changed to reduce power consumption. (Japanese Unexamined Patent Publication No.
No. 028) and a device which displays the remaining communicable time (Japanese Patent Application Laid-Open No. 2-109449), but none of them discloses a technique for changing the transmission speed during communication.

[0011]

In such a conventional system, when a user of a mobile station makes a call for a long time, and when the battery is almost discharged, the user stops the call. There was no way to continue the call except to end it and replace the battery.

The present invention solves such a problem. When the battery of the mobile station is nearing the end of discharge, the transmission speed of the wireless communication between the mobile station and the base station is reduced to half or 1 / the normal rate. 4 to reduce the frequency of transmission signals transmitted from the mobile station, thereby reducing battery consumption during transmission, prolonging the use time of the mobile station, and improving convenience in use. It is an object of the present invention to provide a wireless communication system that can perform the communication.

[0013]

SUMMARY OF THE INVENTION The present invention is intended to reduce the power consumed by a radio of a mobile station in radio communication. A time division multiplex between a base station and a mobile station by a TDMA system is provided. In the digital wireless communication system in which a wireless communication line is set, the base station and the mobile station are provided with control means for reducing a transmission speed of the communication line according to a request from the mobile station. .

The mobile station includes means for detecting the capacity of the battery, and means for generating a request to reduce the transmission rate when the capacity becomes less than or equal to a predetermined value. Preferably, the speed is set in a plurality of stages every half, and the base station is a master telephone fixedly connected to a wired telephone line, and the mobile station is connected to the master telephone by the wireless communication. It can be a handset connected via a communication line.

[0015]

The mobile station detects the battery capacity, and when the battery capacity falls below a certain value, the mobile station requests the base station to change the transmission / reception timing to 1/2 or 1/4 by the control channel. And the base station controls the transmission / reception timing at a low speed, and the mobile station and the base station change the transmission rate of the ADPCM signal, which is the voice code data superimposed on the transmission or reception slot, in accordance with the change in the transmission / reception timing. Control.

[0016] Thus, both the mobile station and the base station can perform radio communication at a transmission / reception timing that is 1/2 or 1/4 that of a normal transmission / reception timing, and voice code data superimposed on this slot signal. Is similarly changed to ま た は or 同 様, so that the call is maintained as it is, and the frequency of the transmission signal transmitted by the mobile station is reduced, so that the battery capacity of the mobile station can be maintained for a long time. .

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. The embodiment of the present invention provides a TDM between a base station and a mobile station.
A time-division multiplex wireless communication line is set by the A method, and the base station and the mobile station have control means for reducing the transmission speed of the communication line according to a request from the mobile station, means for detecting the capacity of the battery, and Means for issuing a request to reduce the transmission rate when the capacity becomes equal to or less than a predetermined value. The transmission speed is set to a plurality of stages every half of the standard transmission speed, and the base station is a master telephone fixedly connected to a wired telephone line, and the mobile station communicates with the master telephone wirelessly. It can be a handset connected via a communication line.

Here, the digital radio communication system according to the present invention will be described with a specific configuration as an example. FIG. 1 is a block diagram illustrating a configuration of a mobile station according to an embodiment of the present invention, and FIG. 2 is a block diagram illustrating a configuration of a base station according to the embodiment of the present invention.

The base station 2 includes a wireless communication unit for transmitting and receiving digital signals by time division multiplex communication according to the TDMA system, a line interface unit 209 for connecting the wireless communication unit to the wired telephone line 210, and the wireless communication unit. A main controller 200 for controlling the means. The mobile station 1 includes the wireless communication unit, a handset 109 connected to the wireless communication unit, a control unit 100 for controlling the wireless communication unit, and a timer unit 113 connected to the control unit 100. , A dial button unit 114, a power supply unit for supplying power, and a battery capacity detection unit 1 for detecting battery capacity
11 are provided.

The main control unit 200 and the control unit 100 include:
Means for varying the transmission rate of the wireless communication between the base station 2 and the mobile station 1 and means for controlling the variation of the transmission rate of the wireless communication between the base station 2 and the mobile station 1 according to the battery capacity are included.

The wireless communication means includes a transmission / reception switching unit 106 connected to an antenna 107 for switching between transmission and reception, a reception amplification unit 105 for amplifying a reception signal, a radio signal demodulation unit 104 for demodulating the amplified signal, An audio signal processing unit 108 for processing an audio signal with the handset 109 and a digital signal from the audio signal processing unit 108 under the control of the main control unit 200 or the control unit 100.
A TDMA / TDD processing unit 101 that modulates or demodulates a DD signal to generate a serial signal to be superimposed on a radio signal, a radio signal modulation unit 102 that modulates a radio signal from the TDMA / TDD processing unit 101, and a radio signal modulation Part 10
And a transmission amplification unit 103 that amplifies the wireless signal from the transmission unit 2 and sends it to the transmission / reception switching unit 106.

The power supply unit includes a battery 110 for supplying power, a power button 115 for opening and closing the power supply, and a power control unit 112 for controlling power supply.

FIG. 3 is a diagram showing the structure of packet data in the embodiment of the present invention. In the packet data according to the embodiment of the present invention, one slot is composed of a data string having a length of 240 bits, and each includes 12-bit head data, 16-bit synchronization data, 20-bit control data, 160-bit voice code data, and 16-bit audio CRC (Cyclic Redunda
ncy Check Code: cyclic redundancy check code) data and 16-bit guard data. 160 bits of the voice code data is a 4-bit ADPCM (Adaptive Differential Pulse Code Modulation) signal, which is composed of a packet of 4 bits × 40 data. Head data other than voice code data related to voice, synchronization data, control data,
CRC data and guard data are data used for starting and synchronizing packet data and correcting errors.
It has nothing to do with the audio signal.

Next, the operation of the embodiment of the present invention configured as described above will be described. FIG. 4 is a diagram showing a normal transmission / reception operation timing in the embodiment of the present invention.
According to this, normally, the mobile station 1 and the base station 2 have 5 ms
Transmission / reception is performed alternately every time, and the ADPCM signal of the transmitted / received audio signal data is 160 bits per slot, so the transmission rate is 32 Kbps (160 bits / 5 m
S) is required. This state is shown in FIGS.

Here, the operation of the mobile station 2 in the embodiment of the present invention will be described with reference to FIG.

The control unit 100 of the mobile station 1 detects the button of the dial button unit 114, controls the timer unit 113, and performs TDMA / TDD (time division multiple access / time division duplex).
The control of the processing unit 101 is performed. TDMA / TDD processing unit 1
01 modulates or demodulates a digital signal from the audio signal processing unit 108 which converts an analog signal with the handset 109 into a digital coded signal and converts a digital coded signal into an analog signal into a TDMA / TDD signal. Perform control processing. This TDMA / TDD processing unit 10
1 generates a TDMA / TDD serial signal to be superimposed on the radio signal.

The transmission signal generated by TDMA / TDD processing section 101 passes through radio signal modulation section 102 and transmission amplification section 103, and is transmitted from transmission / reception switching section 106 to antenna 1
A radio signal is transmitted to the base station 2 via the network 07. A radio signal received from the base station 2 is received via the antenna 107 and is input to the TDMA / TDD processing unit 101 via the transmission / reception switching unit 106, the reception amplification unit 105, and the radio signal demodulation unit 104. The TDMA / TDD processing unit 101 synchronizes the synchronization timing of the TDMA / TDD processing unit 101 based on the received signal from the base station 2 and generates transmission / reception timing.

Next, power control of the mobile station 1 will be described. The battery 110 in the mobile station 1 has a timer 11
3 and the power control unit 112
The power is supplied to the respective circuit units of the wireless unit and the control unit from. The battery 110 is connected to the battery capacity detection unit 111, and information on the battery capacity is always notified to the control unit 100. The power control unit 112 controls the power of the battery 110 to be ON or OFF for each circuit unit of the wireless unit and the control unit by activating the control from the timer unit 113. That is, when the user of the mobile station 1 turns on the power button 115 to enter the operating state, the timer unit 113 first activates the power supply control unit 112 to supply power to each circuit unit of the mobile station 1. I do.

The control unit 100 detects information from the TDMA / TDD processing unit 101 and the dial button unit 115. In the control unit 100, when there is no incoming call from the base station 2 and there is no dial button press information from the user of the mobile station 1, that is, when it is determined that the mobile station 1 is in the standby state, the timer unit 113 sets the timer value of the intermittent time to the timer unit 113. Set. The activation of the timer unit 113 is performed according to TDMA / TDD.
This is performed at the synchronization timing received from the base station 2 by the processing unit 101.

By such control, the timer unit 113
First, the power supply control unit 112 controls the power supply to be turned off, and shuts off power supply to all circuit parts other than the timer unit 113. The timer unit 113 can perform a counting operation because power is always supplied from the battery 110. Since the power consumption of the timer unit 113 is very small, it hardly affects the consumption of the battery.

The timer unit 113 controls power supply to the power supply control unit 112 and supplies power to all circuits when the time of the counter is up, that is, immediately before the reception timing from the base station 2. I do. By this control, power is again supplied to the control unit and the radio unit, and the base station 2
Can be received. When the mobile station 1 is busy, the control unit 100 stops controlling the timer unit 113, and the power control unit 112 shifts to control for supplying power to each circuit unit.

With such control, the mobile station 1 performs intermittent reception during standby to perform battery saving.

Here, the operation when the battery capacity is low, which is a feature of the present invention, will be described.

When the capacity of the battery 110 decreases during a call with the mobile station 1, the battery capacity detection unit 111 notifies the control unit 100 of information indicating the decrease in the battery capacity. When this information is received by the control unit 100, the request data for changing the transmission speed of the wireless communication to 1/2 or 1/4 is set in the TDMA / TDD processing unit 101 on the control data shown in FIG. This control data is received by the base station 2 through a radio section of the mobile station 1 as a radio signal as described above.

On the other hand, when the base station 2 detects a request for changing the transmission rate of the wireless communication, it similarly returns a response signal using the control data, and synchronizes with the transmission rate requested by the mobile station 1 for transmission / reception timing. Transmits a burst signal. After the mobile station 1 also receives the response signal of the base station 2,
It waits for a synchronization burst signal from the base station 2 and changes the transmission speed of wireless communication after re-synchronization is established. According to FIG. 4, the transmission / reception timing between the mobile station 1 and the base station 2 is different from the transmission / reception timings b and c which are normal transmission / reception timings every 5 ms.
As the battery capacity of the mobile station 1 decreases, the transmission / reception timing becomes 10 mS (d and e in FIG. 4) or 20 mS (f and g in FIG. 5).

FIG. 5 shows the relationship between the PCM signal and the ADPCM signal according to the change in the transmission speed of the wireless communication in the embodiment of the present invention. According to FIG. 5, the 64Kbps P
When the CM signal is converted to a 32 Kbps ADPCM signal, 8 bits are converted to 4 bits for compression coding, and at 16 Kbps or 8 Kbps, high-efficiency compression coding is similarly performed by arithmetic processing to 16 Kbps or 8 Kbps.
A Kbps ADPCM signal is generated.

The voice coded data in the wireless communication is realized by using the ADPCM signals at the respective transmission speeds. That is, since the voice code data has 160 bits per slot as described above, 1
By transmitting and receiving every 0 mS or 20 mS, the transmission speed can be superimposed on 16 Kbps (160 bits / 10 mS) or 8 Kbps (160 bits / 20 mS), respectively. Conversely, when an ADPCM signal is inversely converted into a PCM signal, the same procedure is performed, and a 64 Kbps PCM signal can be reproduced.

[0038]

As described above, according to the present invention, when the battery of the mobile station is nearing the end of discharging, the transmission speed of the radio communication between the mobile station and the base station is reduced to half or 1 / the normal rate.
By controlling the transmission rate to 4 and reducing the frequency of the transmission signal transmitted from the mobile station, it is possible to reduce the battery consumption due to transmission, and accordingly, the use time of the mobile station can be prolonged. There is an effect that the convenience in weighing and use can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a mobile station according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a base station according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of packet data according to the embodiment of the present invention.

FIG. 4 is a diagram showing normal operation timings in the embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a PCM signal and an ADPCM signal according to a change in the transmission speed of wireless communication in the embodiment of the present invention.

FIG. 6 is a diagram illustrating transmission / reception operation timing according to the TDMA / TDD method.

FIG. 7 is a diagram showing a call timing according to the TDMA / TDD method.

FIG. 8 is a diagram illustrating operation timing of battery saving.

[Explanation of symbols]

 Reference Signs List 1 mobile station 2 base station 100 control section 101 TDMA / TDD processing section 102 radio signal modulation section 103 transmission amplification section 104 radio signal demodulation section 105 reception amplification section 106 transmission / reception switching section 107 antenna 108 voice signal processing section 109 handset 110 battery 111 Battery capacity detection unit 112 Power control unit 113 Timer unit 114 Dial button unit 115 Power button 200 Main control unit 209 Line interface unit 210 Wired telephone line

Claims (3)

(57) [Claims] Between 1. A base station and a mobile station, is set division multiplex radio communication line when the TDMA system, the base station and the mobile station, voice band signal to be transmitted
Into an ADPCM signal and transmit and receive TDMA slots.
In a digital radio communication system having means for transmitting in Tsu bets, wherein the base station and the mobile station, a control means for reducing the transmission rate of the communication line in response to a request from the mobile station, the mobile station Includes means for detecting battery capacity, and battery
When the capacity falls below a predetermined value, reduce the transmission speed
Means to generate a request to reduce the transmission rate
Means for transmitting to the base station . Wherein said transmission rate, a digital radio communication system according to claim 1, wherein set in a plurality of steps every 2 minutes for a standard transmission rate. 3. The base station is a master telephone fixedly connected to a wired telephone line, and the mobile station is a slave unit connected to the master telephone via the wireless communication line.
2. The digital wireless communication system according to 1.