KR20020016353A - Broadcasting method and device for voice using base station - Google Patents

Abstract

In the DECT wireless communication system, a speaker is installed in a base station, so that a voice can be broadcast when a terminal requests a broadcast.

A voice broadcasting method using a base station according to the present invention comprises the steps of: (a) receiving a signal of a terminal in a DECT system; (b) if the signal is a broadcast request signal, setting a part of received data as previously promised data according to a broadcast request of the terminal and transmitting the predetermined data to a base station; (c) the base station receiving a signal from a DECT system; (d) decoding the received signal as a broadcast signal after step (c) and processing the signal as a voice signal if it is a broadcast signal; (e) broadcasting the signal processed as the voice signal to a speaker provided in the base station.

According to the present invention, when there is a broadcast request from the wired and wireless terminal by setting a part of the received data as a broadcast signal and then the base station to decode it and then to broadcast the voice to the speaker provided in the base station, It is possible to broadcast to people who do not own a terminal or people who do not carry the terminal without providing a broadcasting facility, which increases the efficiency of broadcasting. In addition, a wired terminal can broadcast without occupying a channel. Because we only need to grab channels in, we can increase the efficiency of channel usage.

Description

Voice broadcasting method and apparatus using a base station {BROADCASTING METHOD AND DEVICE FOR VOICE USING BASE STATION}

The present invention relates to a method and apparatus for voice broadcasting using a base station, which enables a base station to broadcast voice by using voice data of the terminal, in particular in a DECT wireless communication system.

In multi-cell wireless communication systems, two or more base stations (BS) are installed to cover a certain area. Digital European Cordless Telecommunication (DECT) refers to Europe. It is a standard of wireless telephone used mainly.

The technical specifications of the DECT system include time division multiple access (TDMA), which is divided by time, for multiple users to access, time division bidirectional communication (TDD) for bidirectional communication in which transmission and reception are divided in time, and frequency bands in a predetermined number. It features frequency division multiple access (FDMA), 188 GHz to 1.90 GHz, Gaussian frequency shift keying frequency modulation (GFSK), which can be used not only for home wireless telephones, but also for contacting private exchanges. It is also widely used in DECT wireless communication system that can be used as a wireless terminal in the premises by installing a base station.

A conventional general DECT wireless communication system is described as follows.

1 is a conceptual diagram illustrating the installation of a general DECT wireless communication system, FIG. 2 is a diagram illustrating a data structure of a DECT protocol, FIG. 3 is a detailed configuration diagram of a DECT interface processor, and FIG. 4 is a detailed configuration diagram of a base station.

1, a DECT system 100 having a processing unit (Wireless Terminal Interface Board) 110 for performing DECT interface processing in a private exchange and exchanging data therethrough; A base station (BS) 210 connected to the DECT interface processor 110 by a cable to form a wireless area of the cell 200; The mobile station 220 communicates with the base station 210 in the DECT standard in the radio area formed by the base station 210. Reference numeral 10 denotes a wired terminal.

The operation of the DECT wireless communication system will be described with reference to FIGS. 1 and 2 as follows.

The DECT system 100 communicates via a wired telephone 10 or a trunk line as a private exchange, and is connected to a base station 210 that forms a wireless area of each cell 200 by cable to transmit data of the mobile station 220. And receive.

To this end, the DECT system 100 has an interface processor 110, and each base station 210 is connected by a cable, and the base station 210 includes a plurality of mobile stations 220 located in a radio area of each cell 300. After transmitting and receiving the data, the received signal is processed and transmitted to the interface processor 110, and the data transmitted from the interface processor 110 is processed and then transmitted to the mobile station 220.

At this time, the mobile station 220 transmits and receives data with the base station 210 according to the DECT standard in the wireless area formed by the base station 210 as a wireless terminal.

Here, referring to FIG. 2 for the data structure of the DECT protocol, FIG. 2 (a) shows one frame structure, (b) shows a full slot structure, and (c) shows the structure of an A field.

Referring to FIG. 2, a frame is divided into a transmission frame for transmitting data and a reception frame for receiving data in a basic time unit of the DECT standard with a physical time of 10 msec. One such frame consists of 24 slots.

A slot is a unit of time divided by 24 frames, and since both data transmission and reception must be performed, one transmission slot and one reception slot are allocated in pairs. In other words, when a user A transmits to slot 0, it should receive to slot 12, and if user A transmits to slot 10, a rule should be received to slot 22. In addition, since there are 12 transmission / reception slots per frame, it can be seen that 12 users can simultaneously talk.

However, due to the limitation of the RF module (see FIG. 4) of the base station 310, it is generally possible to use only 6 slots. In this case, a slot that is not used is called a blind slot, and if slots 0, 2, 4, 6, 8, and 10 are used, slots 1, 3, 5, 7, and 9 cannot be used.

In a frame, one user can transmit and receive data during one slot. Since the frame is continuously repeated, the user can send and receive data once every 10 msec.

In addition, in the frequency channel, DECT has a property of frequency multiplexing connection, and has 10 frequency channels divided into 10 frequency bands of 1.88 GHz to 1.9 GHz. Each slot selects and communicates one of them, and the frequency channel of transmitting and receiving uses the same channel. Since there are 12 slots and 10 frequencies, there are 120 available combinations, and in the case of blind slots, 60 available combinations.

Referring to the structure of the slot shown in (b) of FIG. 2, one slot of the DECT is composed of 480 bits, and is divided into several fields for each data attribute. The S field is a synchronization field and has a synchronization bit for determining the start of a slot and valid data, which is used for mutual synchronization between a base station and a mobile station.

The A field is information field and indicates the type of data of a specific slot and plays a role of wireless situation management and request. The B field is a voice data field and is composed of 320 bits. The X.Z field consists of 8 bits and is a field for error detection occurring in the B field. The guard band, also called the guard field, is an unused area.

Referring to the structure of the A field (in the case of a paging channel) shown in FIG. 2C, the A field header is data identifying the A field, the B field header is data indicating the type of the B field, and the Pt header is A paging header indicates that a corresponding A field is a paging channel, channel data is a management data field regarding a paging channel, and MAC layer information is a medium access control (MAC) layer information field for managing a DECT radio connection. . A-CRC (Cycle Redundancy Check) is a field for error search of the A field.

3 is a detailed configuration diagram of the DECT system 100, and includes an interface processor 110 and a central system 120 that line interface with a base station 210.

The interface processor 110 includes an ASIC including a line drive 111 connected to the base station 310, and a transmit and receive data processor 112a and 112b for processing data transmitted / received to the line drive 111. A unit 112, a Burst Mode Controller (BMC) 113 for processing the DECT protocol, a central processing unit 114 connected to the central system 120 for controlling the BMC 113, and a voice standard in the DECT. It consists of an ADPCM (Adaptive Differential Pulse Code Modulation) processor 115 and a memory 116.

4 is a detailed configuration diagram of the base station 210. The line drive 211 performs a line interface with the interface processor 110, and processes the transmission / reception data of the line drive 211 and the mobile station 220. FIG. An ASIC unit 212 including transmission and reception data processing units 212a and 212b and a signal processed by the transmission data processing unit 212a through the antenna 214 and received through the antenna 214. The RF module 213 outputs an analog signal to the reception data processor 212b.

The operation of the DECT system 100 and the base station 210 will be briefly described. The interface processor 110 connected to the base station 210 receives and transmits data through the line drive 111. Processing is performed by the transmitting and receiving data processing units 112a and 112b of the ASIC unit 112. The BMC 113 is connected to the ASIC unit 112 to adjust the burst mode to process the DECT protocol under the control of the central processing unit 114, and the DECT in the ADPCM processing unit 115 connected to the BMC 113. It processes the voice data and stores the data in the memory 116. The interface processor 110 is collectively controlled by the central system 120.

In addition, the base station 210 connected to the line drive 111 of the interface processor 110 transmits and receives data from the internal line drive 211, and the data is transmitted and received by the base station ASIC unit 212. After processing by the processing units 212a and 212b, the transmission data is processed by the transmission data processing unit 212a, and then the RF module 213 is transmitted to the antenna 214 to the mobile station 220 and transmitted by the mobile station 220. The signal is received by the RF module 213 through the antenna 214, and the signal is processed by the reception data processor 212b and then transmitted to the interface processor 110 through the line drive 211.

The base station 210 always emits a dummy bearer so that the mobile station 220 to make a call knows that the temporal reference is the start of the frame, and the mobile station 320 baselocks the bearer. Set time standards. When making a call, a traffic bearer is formed in another time slot based on the time of the dummy bearer, which is called a general call channel.

Conventional paging (broadcasting) uses a dummy bearer to send information to all mobile stations 310, and because the dummy bearer is not allowed to send the B field, that is, voice data, text information, warning messages, and the like. send. That is, in FIG. 2, the slot structure includes only the S field and the A field (c of FIG. 2). If the user wants to send a voice, the A field should be configured as shown in FIG. 2 using a traffic bearer, and the voice should be sent to the B field.

However, conventionally, in the case of the transmission of a text message, if the user of the mobile station 210 does not have the mobile station 210 at that time, the user cannot see the message, and there is a limit to the amount of information that can be transmitted to the mobile station 210. There was also a problem with the voice transmission. In addition, there is a problem in that the broadcast is not delivered to the mobile station 210 having a call during the broadcast.

In addition, when using a traffic channel, since the voice can be delivered only to a specific mobile station 210, there is no advantage in comparison with a general call, and a method of simultaneously delivering voice by setting up multiple traffic channels to several mobile stations 210 is limited. The use of wireless channels has the disadvantage of reducing the available wireless channels. In this case, too, since the user must have the mobile station 210, there is a possibility that a broadcast is not transmitted as described above.

The present invention has been made to solve the above-mentioned conventional problems. The present invention provides a speaker in a base station, sets a preset broadcast signal in the DECT system when a broadcast request is made by the terminal, and decodes the broadcast signal. SUMMARY OF THE INVENTION An object of the present invention is to provide a voice broadcasting method and apparatus using a base station to broadcast a voice through a speaker.

1 is a conceptual diagram of a conventional DECT wireless communication system.

2 is a data structure of the DECT protocol.

3 is a detailed configuration diagram of a conventional DECT interface processing unit.

4 is a detailed configuration diagram of a conventional DECT base station.

5 is a conceptual diagram of a DECT wireless communication system in a voice broadcasting apparatus using a base station according to the present invention;

6 is a flowchart showing an operation procedure of an interface processor in the voice broadcasting method using the base station according to the present invention.

7 is a block diagram showing a voice broadcasting apparatus using a base station according to the present invention.

8 is a data structure showing a relationship between a DECT slot and an ADPCM slot for the present invention.

9 is a flowchart illustrating a voice broadcasting method using a base station according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100 ... DECT System 110 ... Interface Processing Unit

200 ... cell 210 ... base station

220 ... Dongkook 211,411 ... Line drive

212,420 ... Base station ASIC section 213,430 ... RF module

214,440 Antenna 212a, 421 Transmission data processing unit

212b, 412 ... Receive data processor 423 Decryption means

423a ... A Field Decryptor 423b ... Pt Information Decryptor

424 ... Voice Conversion Means 424a ... ADPCM Data Extraction Unit

424b ... ADPCM Frame and Clock Generator 424c ... ADPCM Processing Unit

425 ... voice signal processor 400a ... speaker

In the DECT system according to the present invention, a voice broadcasting method using a base station is provided.

(a) receiving a signal of a terminal in a DECT system;

(b) if the signal is a broadcast request signal, setting a part of received data as previously promised data according to a broadcast request of the terminal and transmitting the predetermined data to a base station;

(c) the base station receiving a signal from a DECT system;

(d) decoding the received signal as a broadcast signal after step (c) and processing the signal as a voice signal if it is a broadcast signal;

(e) broadcasting the signal processed as the voice signal to a speaker provided in the base station.

Preferably, when the broadcast request signal is a request of a mobile station, a first step of storing the received voice data in a buffer; and after the first step, select a transmission slot of the corresponding mobile station, and then select a part of the data into a promised broadcast mode. And a third step of connecting the data stored in the buffer to the DECT slot and transmitting the data stored in the buffer to the base station after the second step.

Preferably, when the broadcast request signal is a request from a wired terminal, a first step of selecting a blind transmission slot, a second step of setting a part of received data to a promised broadcast mode after the first step, and the broadcast If set to the mode further comprises a third step of connecting the ADPCM data to the DECT data slot.

Preferably, the signal transmitted to the base station determines whether the header of the A field and the Pt information field are the broadcast signals set in the DECT system, and if the broadcast signal is a broadcast signal, stores the data of the B field in the buffer. And transmitting the data in synchronization with the ADPCM slot and processing the data as an audio signal to the speaker.

Voice broadcasting apparatus using a base station according to the present invention,

In the DECT wireless communication system comprising a DECT system having an interface processing unit for the DECT processing, and a base station for processing the data received from the DECT system to transmit to the mobile station and processing the data received from the mobile station to the interface processing unit; ,

The base station; Decoding means for receiving the transmission signal from the DECT system to decode the broadcast signal, Voice conversion means for converting the information from the decoding means into a voice signal, Processing the converted voice signal and output to the speaker It characterized in that it comprises a voice signal processing means.

Preferably, the decoding means comprises an A field decoding unit for decoding the A field of the broadcast signal, and a Pt information decoding unit for decoding the Pt information in the decoded A field, wherein the A field decoding unit is the A field. The header information of the Pt information decoding unit determines whether the bit combination is assigned to the broadcast mode in the Pt information field of the A field and is assigned to 1111.

Preferably, the voice conversion means includes an ADPCM data extractor for extracting the DECT data transmitted from the decryption means into ADPCM data, an ADPCM frame and clock generator for generating a frame and a clock for processing the ADPCM data, and the ADPCM And an ADPCM processor for loading data extracted as data according to the frame and clock.

Hereinafter, with reference to the accompanying drawings as follows.

5 is a conceptual diagram schematically showing a voice broadcasting apparatus using a base station according to the present invention, FIG. 6 is a flowchart of a broadcast data transmission flow of a DECT interface processor according to the present invention, and FIG. 7 is a voice broadcasting using a base station according to the present invention. 8 is a block diagram showing a relationship between a DECT slot and an ADPCM slot according to the present invention, and FIG. 9 is a flowchart showing a voice broadcasting method using a base station according to the present invention.

5 and 6, the base station 400 includes a speaker 400a, processes the transmission and reception data with the line drive 410, decodes a broadcast signal from the transmission data, and then analyzes the broadcast signal. An ASIC unit 420 for converting voice data, an RF module 430 and an antenna 440, and a voice signal processing unit 425 for processing and outputting the voice data to the speaker 400a.

The ASIC unit 420 reads whether the transmission and reception data processing units 421 and 422 are broadcast for decoding the data processed by the transmission data processing unit 421, and the Pt information field of the read data is 1111. Decryption means 423 comprising an A-field decryption unit 423a and a Pt information decryption unit 423b for confirming recognition, and an ADPCM data extraction unit for converting DECT data input from the decryption means 423 into ADPCM data. 424a, an ADPCM frame and clock generator 424b, and an ADPCM processor 424c.

Referring to the accompanying drawings, a voice broadcasting method and apparatus using a base station in a DECT system configured as described above will be described below.

First, referring to FIG. 5, the DECT system 300 recognizes a broadcast request from the wired terminal 20 or the mobile station 400 in the internal interface processor 301 and is pre-allocated for the broadcast request. If the data is set to broadcast data and transmitted to the base station 400, the base station 400 decodes the data and broadcasts the voice signal through the speaker 400a if the broadcast signal is broadcast.

Referring to the operation of the interface processing unit 301, it is determined whether the received broadcast signal is a signal requested by the broadcast terminal from the wired terminal 20 or a signal requested by the mobile station 400 (S101). (S102).

In this case, when the broadcast request signal from the wired terminal S101 does not need to set a channel to the mobile station 220, a blind slot is not used among the DECT slots of FIG. 2 (S103) (S104). In other words, the wireless channel can be used over the wire even without using a blind slot.

Thereafter, broadcast signal information is set, which sets the A field in the frame to the paging mode and sets the Pt information field to a bit combination of 1111 (S104). The bit combination of 1111 at this time is a bit combination that is not used conventionally.

Then, the voice data of the ADPCM slot is connected to the DECT slot (S106), and when connected to the DECT slot, the data is transmitted to the corresponding base station 400 in the DECT format (S107).

Then, the base station 400 broadcasts the voice through the provided speaker 400a, and sends the transmitted data back to the wired terminal 20 so that the person who is broadcasting can hear his / her voice. Thereafter, the broadcast is terminated by the broadcast end signal (S108).

On the other hand, in the case of the request of the mobile station 220 as a result of the determination in step S102, since the request is made wirelessly by forming a call channel, the voice data is once stored in the buffer without setting the blind slot (S109).

Then, the transmission slot of the mobile station 400 is selected and the A field is set to the paging mode (S110) (S111). In this case, when the A field is set to the paging mode, the Pt information field is set to a bit combination of 1111 (S112), the data stored in the buffer is connected to the DECT slot, and the data is transmitted to the base station 400 to be provided in the base station 400. The voice signal is broadcast through the speaker 400a (S113 and S107).

The base station 400 also sends the data back to the mobile station 220 so that the user of the mobile station 220 can hear their voice.

This voice data is set as a broadcast signal and connected to the DECT slot and transmitted to the base station 400. The base station 400 decodes the set broadcast signal and converts it into a voice signal and then broadcasts it to the speaker 400a. .

Referring to FIG. 7, the DECT signal is input to the base station ASIC unit 420 through the line drive 410 of the base station 400 connected to the DECT interface processor 301. The base station ASIC unit 420 processes the data in the transmission data processing unit 421 and outputs it to the RF module 430, and the processed DECT data is decoded by the decoding unit 423 and then voice conversion unit 424. ) Is converted into voice data and output to the voice signal processor 425.

Then, the RF module 430 sends the signal back to the mobile station 220 through the antenna 440 to listen to its own voice.

The decryption means 423 of the base station ASIC unit 420 is composed of an A field decryption unit 423a and a Pt information decryption unit 423b, and the A field decryption unit 423a is transmitted by the transmission data processing unit 421. The processed data is input and the data is read for broadcast or general call. This is a part for reading the A field header, which is normally defined as 111 for broadcasting.

When the Pt information decoding unit 423b reads for broadcasting by the A field decoding unit 423a, the Pt information decoding unit 423b checks whether or not the Pt information field is a bit combination of 1111. It outputs to the speech conversion means (424).

The voice converting means 424 includes an ADPCM data extractor 424a, an ADPCM frame and clock generator 424b, and an ADPCM processor 424c, wherein the ADPCM data extractor 424a has a Pt information field of 1111. In this case, only data (voice data) of the B field is extracted and stored.

In this case, since the data processed by the interface processor 301 is DECT data as shown in (d) of FIG. 8, the ADPCM frame and clock generator 424b may have an ADPCM form as shown in FIG. 8 (c). A frame of (a) and a clock of (b) of FIG. 8 are generated.

Then, the ADPCM processor 424c converts the extracted data into ADPCM data in the DECT slot so as to fit the frame and the clock, and outputs it to the voice signal processor 425.

The voice signal processor 425 converts the ADPCM data processed by the ADPCM processor 423 of the base station ASIC unit 420 into a signal that can be heard by a real person, and the converted signal is voiced through the speaker 400a. Broadcast by signal.

Referring to FIG. 8, the conversion from DECT data to ADPCM data and its inverse transformation will be described. As shown in (a) (b) (c) of FIG. 8, an ADPCM frame is repeated every 125usec, and one frame is used. Consists of 32 ADPCM slots, each bit processed by a 2.048 MHz clock. One slot of ADPCM consists of 8 bits, which are actually used by the first 4 bits.

That is, one bit width = 1 / 2.048usec, one ADPCM slot = one bit width x 8 = 8 / 2.048usec, 32 slot times = 32 x 8 /(2.048usec) = 125usec.

As shown in (d) of FIG. 8, the B field, which is the voice data field of one slot of DECT, is composed of 320 bits and one frame of DECT is 10 msec. Thus, 80 ADPCM frames are configured during one frame. That is, the number of ADPCM frames is (10/125) x 1000 = 80.

Therefore, the data of one slot of ADPCM is 4 bits and is collected for 80 frames, so that 320 bits are configured during the DECT frame time.

The operation procedure of the base station 400 will be briefly described with reference to FIG. 9. After the DECT data received by the line drive 410 is processed by the transmission data processing unit 421, the data is decoded by the decoding means 423. If the A field header is read by the broadcast message, the Pt information field is read (S201) (S202) (S203). If the bit combination of the Pt information field is 1111, the voice conversion means 424 stores the data of the B field (S204), converts the data into voice data in synchronization with the ADPCM slot, and converts the data into the voice signal processor 425. If it is transmitted (S426), the voice signal processing unit 425 processes the voice signal and broadcasts it to the speaker 400a (S427).

Therefore, when the speaker 400a is provided in the base station 400, the mobile station 220 sets the data as a broadcast signal when the broadcast request is received, and transmits the data to the base station 400, the base station 400 broadcasts the broadcast. After decoding the signal, it is converted into voice data and broadcasted to the speaker 400a.

As described above, the voice broadcasting method and apparatus by the base station according to the present invention can broadcast to both users who do not have a mobile station and other people who do not use the mobile station in a space such as a small office. The cost savings can be expected by increasing the efficiency and eliminating the need to install a separate broadcasting facility. Unlike conventional methods, broadcasting from a wired terminal does not occupy a channel. can do.

In addition, even when broadcasting in a mobile station, once the channel is caught in the mobile station, the broadcast can be performed through a base station, thereby increasing efficiency in using a wireless channel.

Claims (12)

(a) receiving a signal of a terminal in a DECT system; (b) if the signal is a broadcast request signal, setting a part of the received data as previously promised data according to a broadcast request of the terminal and transmitting the predetermined data to a base station; (c) the base station receiving a signal from a DECT system; (d) decoding the received signal as a broadcast signal after step (c) and processing the signal as a voice signal if it is a broadcast signal; (e) broadcasting the signal processed by the voice signal to a speaker provided in the base station. The method of claim 1, A first step of storing received voice data in a buffer when the broadcast request signal is a request of a mobile station; and selecting a transmission slot of the mobile station after the first step and setting a part of the data to a promised broadcast mode. And a second step of connecting the data stored in the buffer to the DECT slot and transmitting the data stored in the buffer to the base station after the second step. The method of claim 1, When the broadcast request signal is a request from a wired terminal, a first step of selecting a blind transmission slot, a second step of setting a part of received data to a promised broadcast mode after the first step, and setting the broadcast mode And a third step of connecting the ADPCM data to the DECT data slot. The method according to claim 1 or 2 or 3, The promised broadcasting mode of the data sets the A field to a paging mode and sets the bit combination (1111) not to use the Pt information field contained in the A field. The method of claim 1, After receiving the signal of the terminal, it is determined whether the broadcast request signal is a wired terminal or a mobile station, and transmits the broadcast signal to the corresponding terminal characterized in that to listen to his voice through his terminal Voice broadcasting method using a base station. The method of claim 1, The signal transmitted to the base station determines whether the header of the A field and the Pt information field are the broadcast signals set in the DECT system, and if the broadcast signal is a broadcast signal, stores the data of the B field in the buffer, and stores the stored data in the ADPCM. And synchronizing to the slot and processing the same as a voice signal for broadcasting to a speaker. A DECT system having an interface processor for setting a broadcast signal when there is a DECT process and a broadcast request signal; A mobile station and a wired terminal for making a broadcast request; Receiving means for receiving a signal from the interface processing unit and transmitted to a mobile station and a wired terminal, decoding means for decoding the broadcast signal, voice conversion means for converting the voice signal using the information decoded from the decoding means, and the converted Voice broadcasting apparatus using a base station comprising a base station including a voice signal processing means for processing the voice signal and outputs to the speaker. The method of claim 7, wherein The decoding means comprises: an A field decoding unit for decoding the A field of the broadcast signal, and a Pt information decoding unit for decoding the Pt information in the A field if the decoded information is a broadcast signal. The method of claim 8, The A field decoding unit reads the header information of the A field to determine whether it is set as a broadcast signal, and the Pt information decoding unit determines whether a bit combination is assigned to 1111 in the broadcast mode in the Pt information field of the A field. Voice broadcasting apparatus using a base station. The method of claim 7, wherein The voice converting means includes an ADPCM data extractor for extracting only B field data of the DECT data transmitted from the decryption means, an ADPCM frame and clock generator for generating a frame and a clock for processing the ADPCM data, and the extracted B Voice broadcasting apparatus using a base station characterized in that it comprises an ADPCM processing unit for loading the field data according to the frame and clock. The method of claim 7, wherein The broadcast signal received by the base station is set by the DECT system and the base station in advance of the broadcast data, the preset broadcast data is set in advance in accordance with the request of the terminal in the DECT system, the base station is characterized in that the base station decrypts it Voice broadcasting device used. The method of claim 7, wherein The mobile station and the wired terminal that made the broadcast request can listen to the voice information requested by the mobile station to their terminal by the DECT system and the base station.