JP5860652B2 - Wireless terminal and wireless communication system - Google Patents

Description

  The present invention relates to a radio communication system to which two or more mobile stations belong under one base station, and more particularly to control of data of a direct communication wave and a base station loopback communication wave.

  As a digital radio system that is currently in practical use in digital radio terminals for land mobile communications, ARIB STD-T61 (Association of Radio Industries and Business Standards-T61: Non-Patent Document 1) formulated by the Radio Industries Association of Japan There is a narrowband digital communication system defined, or a mobile communication system defined by ARIB STD-T79 (Association of Radio Industries and Businesses Standard-T79).

  These digital communication systems are composed of a plurality of base stations and a large number of mobile stations, and a direct communication mode between mobile stations for performing communication between mobile station terminals and a command console and mobile radio via the base station radio apparatus. There is a base station communication mode for performing communication between stations.

  FIG. 1 is a schematic diagram illustrating an example of a conventional wireless communication system.

  1 includes a base station 101, mobile stations 102-1, 102-2,... 102-N. Hereinafter, the unspecified mobile station is expressed as “mobile station 102-1 etc.”.

  The base station 101 is an infrastructure facility that communicates with the mobile station 102-1 and the like.

  The mobile station 102-1 is a mobile station such as an in-vehicle wireless device or a handheld portable wireless device mounted on a vehicle or the like.

  In the base station communication mode, the uplink frequency FL 103 and the downlink frequency FH 104 from the mobile station 102 to the base station 101 form a set of pair waves, and communication is performed between the base station 101 and the mobile station 102.

  In the direct communication mode between mobile stations, communication between the mobile stations 102-1 and 102-2 using the frequency FL103 (direct communication wave) without passing through the base station 101, and from the mobile station 102 via the base station 101 Communication (base station loopback communication wave).

  In such a communication mode, for example, when the mobile station 102-1 has a function capable of receiving two waves, a base station loopback communication wave from the mobile station 102-2 (the base station 101 using the upstream wave FL103). And the direct communication wave FL103 can be received. At this time, it is also assumed that each communication wave is output from a separate audio output device (speaker or the like).

  Japanese Patent Application Laid-Open No. 2001-036961 (Patent Document 1) is cited as a prior art.

JP 2001-036961 A

ARIB STD-T61 ARIB STD-T79

  However, as described above, when it has a functional configuration capable of receiving both the base station loopback communication wave and the direct communication wave FL103, the upstream wave FL103 from the mobile station 102-2 is used to transmit the downstream wave via the base station 101. Both the base station loopback communication wave received by the FH 104 and the direct communication wave FL103 from the mobile station 102-2 can be received.

  At that time, when there is a mobile station 102-1 capable of outputting each communication wave from a separate audio output device (speaker or the like), audio transmission between the base station loopback communication wave and the direct communication wave between the mobile stations When voice delay occurs due to a path difference (artificial multipath fading) or the like, two voices may be heard as an echo. The field of use of commercial radio includes fireworks, gas, electric power, airports and other public institutions, and such unpleasant echoes can interfere with business execution.

  For example, in order to provide important voice information such as an emergency warning at the time of a disaster, the voice information may be difficult to hear. Moreover, even in consumer use, it sounds like echo or howling, and it is difficult to say that it is a comfortable operating environment (the occurrence of this problem will be described again in FIG. 6).

  An object of the present invention is to provide means for making a user-friendly and easy-to-listen call by muting or muting the sound output level of one of two sound output devices.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  A wireless terminal according to a typical embodiment of the present invention has two signals, a direct communication wave used for direct communication between wireless terminals and a base station looped communication wave for performing relay communication between the wireless terminals via a base station. In a wireless communication system that can receive audio from different speakers or synthesize received signals and output sound from a single speaker, and demodulate the received signals so that the demodulated signals are transmitted from the same transmitting terminal. In the case of a transmission signal, one of the audio outputs is muted or weak sound.

  The wireless terminal compares the IDs of the transmitting-side wireless terminals included in the signals of the direct communication wave and the base station return communication wave, and as a result of the comparison, in the signals of the direct communication wave and the base station return communication wave If the IDs of the wireless terminals on the transmission side included in the two match, one audio output may be muted or weak.

  In addition, the wireless terminal calculates and compares the received signal strengths of the signals of the direct communication wave and the base station looped communication wave, and sets the audio output corresponding to the wave having the lower value to mute or weak sound. It may be characterized.

  By using a radio communication system using a mobile station and a base station according to the present invention, it is possible to prevent the occurrence of echoes due to reproduction of the same audio data at different timings due to propagation delay, and provide a comfortable operating environment. It becomes possible.

It is the schematic which shows an example of the conventional radio | wireless communications system. It is the block diagram which showed an example of the radio | wireless machine audio | voice part at the time of having two audio | voice output parts in connection with this invention. It is a conceptual diagram showing the audio | voice data format of the data frame regarding the data transmission / reception in this invention. It is a conceptual diagram showing the flow of a process in the case of performing audio | voice data communication, without performing via a base station in this invention. It is a conceptual diagram showing the flow of a process in the case of performing voice data communication via the base station in this invention. It is a conceptual diagram showing the flow of the process at the time of 2 system | strain input in the case of not performing the process concerning this invention. It is a conceptual diagram showing the flow of the process at the time of two system input in the case of performing the process concerning this invention. It is a conceptual diagram showing the flow of the process at the time of the two-system input originating in the different mobile station in the case of performing the process regarding this invention.

  In the following embodiment, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, it is not irrelevant to one another, and one is related to some or all of the other, details, supplementary explanations, and the like. Also, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except for the specific number, the number may be more than or less than the specified number.

  Further, in the following embodiments, it is needless to say that the constituent elements are not necessarily essential unless particularly specified and apparently essential in principle.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 2 is a block diagram showing an example of a radio voice unit 200 having two systems of voice output units according to the present invention.

  The radio voice unit 200 includes a control unit 201, antennas 202 and 203, radio units 204 and 205, AIUs 209 and 210, amplifiers 211 and 212, speakers 213 and 214, and a microphone 215.

  The control unit 201 is a signal control circuit that includes a signal processing unit 206, an MPU 207, and a PLD 208 therein.

  The antennas 202 and 203 are resonance circuits for receiving radio waves input from the outside and extracting analog signals.

  The wireless units 204 and 205 are wireless circuits that perform amplification and demodulation of analog signals obtained by the antennas 202 and 203 and change the data format to be handled by the control unit 201. In the example of FIG. 1, a radio unit corresponding to both the FL 103 and the FH 104 is prepared.

  Here, the signals received from the different antennas 202 and 203 are supplied to the radio units 204 and 205, respectively. However, the signals received by the radio units 204 and 205 are divided by dividing the output of the antenna with one antenna. May be configured to supply.

  In the present invention, it is assumed that the frequency of the radio wave in the upstream direction (from the mobile station to the base station) and the frequency of the radio wave in the downstream direction (from the base station to the mobile station) are different. In addition, it is necessary to receive radio waves output from other mobile stations in the uplink direction (from the mobile station to the base station). Therefore, in order to support both FL103 (upward direction) and FH104 (downward direction), it is assumed that the wireless units 204 and 205 are wireless units corresponding to different frequencies. However, when a multiplexing method such as a code division multiplexing method is used, it is possible that both have the same frequency. In addition, when a multiplexing method such as a code division multiplexing method is used, there may be a case where only one wireless unit is required when the processing capability of the signal processing unit 206 is high. The present invention does not exclude these cases. Here, it is assumed that there are two radio units. For convenience, the wireless unit corresponding to the FL 103 is referred to as a wireless unit 204, and the wireless unit corresponding to the FH 104 is referred to as a wireless unit 205.

  The signal processing unit 206 is a circuit that performs input / output signal processing such as input / output signal level adjustment, modulation / demodulation, and digital / analog conversion / analog / digital conversion.

  The MPU 207 is a processing device that controls the signal processing unit 206.

  The PLD 208 is a programmable logic device for adding functions on the user side.

  The AIUs 209 and 210 are audio output codec circuits. It has a function of converting audio data in digital format output from the signal processing unit 206 into analog format. In this figure, the AIU 210 needs to process the input from the microphone 215 as well. Therefore, the AIU 210 also needs to perform conversion processing from an analog signal to a digital signal.

  The amplifiers 211 and 212 are amplifiers that amplify analog audio data output from the AIUs 209 and 210.

  The speakers 213 and 214 are speakers that output the audio data amplified by the amplifiers 211 and 212.

  The microphone 215 is a microphone for inputting the voice of the operator of the wireless device including the wireless device sound unit 200.

  Next, the operation of the radio sound unit 200 will be described.

  The analog audio signal input from the microphone 215 is converted into a digital signal by the AIU 210. The audio signal converted into a digital signal through the control unit 201 is input to the radio unit 204. An audio signal is output from the antenna 202 after being subjected to transmission path coding by the radio unit 204.

  At the time of reception, the audio digital signal processed by the control unit 201 via the antenna 202 and the radio unit 204 is converted into an analog signal by the AIUs 209 and 210, amplified by the amplifiers 211 and 212, and the speakers 213, 214.

  Here, consider a case where the radio voice unit 200 receives both the base station loopback communication wave and the direct communication wave. Processing is performed by the signal processing unit 206 via the antennas 202 and 203 and the wireless units 204 and 205. At this time, in the present application having two types of transmission forms of the base station return communication wave and the direct communication wave, since it corresponds to transmission to the base station, the FL 103 belonging to the upstream direction and the FH 104 which is the downstream signal from the base station Are treated as separate signals (voice data) having different frequencies.

  Thus, by receiving the same audio data as different signals due to the difference in the propagation path and outputting them as voice, the output corresponding to the delay due to the difference in the propagation path is shifted. Thus, it is an object of the present invention to prevent unpleasant phenomena such as echo and howling.

  Next, the format of a data frame related to data transmission / reception in the present invention will be described.

  FIG. 3 is a conceptual diagram showing an audio data format of a data frame 300 related to data transmission / reception in the present invention. This data format corresponds to the synchronization burst (SB0) described in “4.1.7 Functional channel definition” of ARIB STD-T61.

  This data frame 300 includes a synchronization word 302 and an information symbol 303. Note that the guard time is omitted in the figure.

  The synchronization word 302 is a bit string used for frame synchronization. In the above-mentioned ARIB STD-T61 “4.1.7 Functional channel definition”, LP + R, Pb, RI, and SW are indicated.

  The information symbol 303 is a portion represented by the parameter information channel PICH (PI) in the ARIB STD-T61. The parameter information channel PICH is a point-to-point or point-to-multipoint bi-directional channel, and is a functional channel for transferring user-specific information or the like accompanying a synchronization burst. In the present invention, FH 104 is a point (base station) -point (a mobile station), and FL 103 is a point (a mobile station) -multipoint (a base station and another mobile station).

  In this information symbol 303, an individual information storage area 304 is secured.

  The individual information storage area 304 is a storage area for storing information relating to the transmission source mobile station of the FL 103 and information relating to the transmission source base station of the FH 104. Information related to the transmission source mobile station of the FL 103 is stored in the mobile station individual ID 305 in the individual information storage area 304. Further, information regarding the transmission source base station of the FH 104 is stored in the base station individual ID 306.

  The mobile station individual ID 305 is a data area for storing an identifier indicating the source mobile station.

  The base station individual ID 306 is a data area for storing an identifier indicating the base station of the transmission source.

  Note that what is used as the information related to the transmission source mobile station of the FL 103 and the information related to the transmission source base station of the FH 104 is a design matter, and is not limited here.

  Next, how communication is performed using this data format will be described.

  FIG. 4 is a conceptual diagram showing the flow of processing when voice data communication is performed without going through the base station in the present invention. In this case, a case is assumed in which only direct communication between the mobile station 102-1 and the mobile station 102-2 is possible due to a failure occurring in the base station 101 or a stop of the relay function.

  Mobile station 102-1 outputs audio data on FL103. At this time, the mobile station individual ID 305 that is the data area of the individual information storage area 304 of the information symbol 303 in the FL 103 stores an ID indicating the mobile station 102-1. On the other hand, nothing is stored in the base station individual ID 306 in the individual information storage area 304.

  In such a state, no multipath problem occurs, so no additional processing occurs.

  FIG. 5 is a conceptual diagram showing the flow of processing when voice data communication is performed via a base station in the present invention. In this case, it is assumed that the mobile station 102-1 and the mobile station 102-2 are separated from each other and the FL 103 cannot directly communicate.

  The mobile station 102-1 adds audio data to the FL 103-2 and outputs it. At this time, the mobile station individual ID 305, which is the data area of the individual information storage area 304 of the information symbol 303 in the FL 103-2, stores an ID indicating the mobile station 102-1. On the other hand, nothing is stored in the base station individual ID 306 in the individual information storage area 304 as in FIG.

  The base station 101 receives this. The base station 101 substitutes information regarding its own base station into the base station individual ID 306 which is the data area of the individual information storage area 304 of the received information symbol 303 of the FL 103-2.

  Substituting information symbol 303 after the substitution, base station 101 transmits FH 104-2 to mobile station 102-2. The mobile station 102-2 receives this and performs audio output from the speaker 213 or 214.

  In this case, the multipath problem does not occur.

  Next, a case where the processing according to the present invention is not performed will be described.

  FIG. 6 is a conceptual diagram showing the flow of processing at the time of two-system input when processing related to the present invention is not performed.

  In this case, the mobile station 102-1 adds the audio data to the FL 103-3 and outputs it. At this time, the mobile station individual ID 305 that is the data area of the individual information storage area 304 of the information symbol 303 in the FL 103-3 stores an ID indicating the mobile station 102-1. Also, nothing is stored in the base station individual ID 306 in the individual information storage area 304.

  It is assumed that the base station 101 and the mobile station 102-2 have received this FL 103-3. In this embodiment, the base station 101 inputs its own base station ID to the base station individual ID 306 in the individual information storage area 304. However, since the transmission is from the base station, the ID indicating the mobile station 102-1 recorded in the mobile station individual ID 305 that is the data area of the individual information storage area 304 of the information symbol 303 in the FL 103-3 is FH104. 3 is not recorded in the mobile station individual ID 305 which is the data area of the individual information storage area 304 of the information symbol 303 in -3. Thus, the received audio data of FL103-3 is transmitted as FH104-3 to the mobile station 102-2.

  The audio data of FL103-3 and the audio data of FH104-3 are the same. However, there is no means for identifying that both are the same. Therefore, the mobile station 102-2 that has received them outputs both. As a result, if communication waves are output from separate audio output devices (speakers or the like), they will sound like echoes or howling.

  The embodiment of FIG. 7 corresponds to the problem of FIG. FIG. 7 is a conceptual diagram showing the flow of processing at the time of two-system input when processing related to the present invention is performed.

  Also in the case of the present invention, the mobile station 102-1 puts voice data on the FL 103-4 and outputs it. At this time, the mobile station individual ID 305 that is the data area of the individual information storage area 304 of the information symbol 303 of the FL 103-4 stores an ID indicating the mobile station 102-1. The base station individual ID 306 in the individual information storage area 304 is the same as the conventional one.

  The voice data output from the mobile station 102-1 placed on the FL 103-4 is received by the mobile station 102-2 and the base station 101.

  The base station 101 receives the audio data on the FL 103-4 and performs internal processing based on this.

  The base station 101 copies the contents of the individual information storage area 304 on the FL 103-4 to the individual information storage area 304 on the FH 104-4. Then, the base station 101's own ID is written in the base station individual ID 306 in the individual information storage area 304 on the FH 104-4 generated by duplication. Thereafter, the same data as the received data on FL103-4 is output to mobile station 102-2 via FH104-4.

  In this way, the mobile station 102-2 receives both the audio data on the FL 103-4 output from the mobile station 102-1 and the audio data on the FH 104-4 transmitted from the base station 101. .

  The mobile station 102-2 compares the mobile station individual ID 305 in the audio data individual information storage area 304 on the FL 103-4 with the mobile station individual ID 305 in the audio data individual information storage area 304 on the FH 104-4. To do. If these two are different, the mobile station 102-2 outputs both audio data on the FL 103-4 and audio data on the FH 104-4.

  On the other hand, the mobile station individual ID 305 in the audio data individual information storage area 304 on FL103-4 and the mobile station individual ID 305 in the audio data individual information storage area 304 on FH 104-4 matched. If so, set one of them to silence.

  By doing so, the audio data of either FL103-4 or FH104-4 is reproduced and the occurrence of echoes is prevented.

  In addition to making one silent, it is possible for the mobile station 102-2 to avoid a substantial echo by making one weak.

  Note that which one is to be reproduced is a design matter and is not limited. For example, the radio wave condition is often better via the base station 101. Therefore, the mobile station 102-2 may reproduce only the audio data attached to the FH 104-4 on the FH 104-4 within a certain time after receiving the FL 103-4. In addition, processing such as playing back on a first-come-first-served basis, assuming that FL103-4 on the propagation path always arrives earlier, and always playing back only FL103-4 is also conceivable.

  Further, consider the operation when the direct communication wave and the base station loopback communication wave are transmitted from different mobile stations.

  FIG. 8 is a conceptual diagram showing the flow of processing at the time of two-system input originating from different mobile stations when processing related to the present invention is performed.

  In this figure, output is performed from the mobile station 102-1 to the mobile station 102-2 by direct communication waves. In addition, output is performed from the mobile station 102-3 to the mobile station 102-2 by a base station return communication wave.

  The mobile station 102-1 puts voice data on the FL103-5 and outputs it. At this time, the mobile station individual ID 305, which is the data area of the individual information storage area 304 of the information symbol 303 of the FL 103-5, stores an ID indicating the mobile station 102-1. Also, the base station individual ID 306 in the individual information storage area 304 is undefined as in the past.

  On the other hand, the mobile station 102-3 puts voice data on the FL 103-6 and outputs it. At this time, the mobile station individual ID 305 that is the data area of the individual information storage area 304 of the information symbol 303 of the FL 103-6 stores an ID indicating the mobile station 102-3. Also, the base station individual ID 306 in the individual information storage area 304 is undefined.

  The voice data output from the mobile station 102-3 placed on the FL 103-6 is received by the base station 101.

  The base station 101 copies the contents of the individual information storage area 304 on the FL 103-6 to the individual information storage area 304 on the FH 104-6. Then, the base station 101's own ID is written in the base station individual ID 306 in the individual information storage area 304 on the FH 104-6 generated by duplication. Thereafter, the same data as the received data on the FL 103-6 is output to the mobile station 102-2 via the FH 104-6.

  The mobile station 102-2 that has received both the FH 104-6 and FL103-5 compares the mobile station individual ID 305 in the individual information storage area 304 of each of the FH 104-6 and FL103-5 in the same manner as in FIG. .

  However, the mobile station individual ID 305 in the individual information storage area 304 of the FH 104-6 stores a value indicating the mobile station 102-3. The mobile station individual ID 305 in the individual information storage area 304 of the FL 103-5 stores a value indicating the mobile station 102-1. In this case, since the two data are different, the mobile station 102-2 can perform a smooth operation by outputting both voices from the speakers 213 and 214.

  According to the first embodiment described above, direct communication is possible in a wireless communication system capable of receiving two signals of a direct communication wave and a base station loopback communication wave between wireless terminals and outputting sound from a speaker. When the wave and the base station loopback communication wave signal are transmission signals from the same transmission terminal, specifically, the mobile station in the individual information storage area 304 included in the direct communication wave and the base station loopback communication wave signal If the individual IDs 305 are compared and matched, one sound output can be muted or weak to prevent unpleasant phenomena such as echo and howling, thus providing a comfortable operating environment. It becomes possible.

<Second Embodiment>
In the first embodiment described above, the mobile station individual IDs 305 in the individual information storage area 304 included in the signals of the direct communication wave and the base station loopback communication wave are compared. In the second embodiment, the received signal strength (RSSI: Received Signal Strength Indication) of each of the direct communication wave and the base station loopback communication wave is calculated. This is an example in which the audio output corresponding to the wave with the lower value (level) is muted or weak.

  In the second embodiment, the basic part such as the configuration and operation of the radio voice unit 200, the flow of processing when voice data communication is performed, and the flow of processing when two systems are input are the same as those in the first embodiment. Since it is the same as that of the first embodiment, here, the parts different from the first embodiment will be mainly described.

  Also in the second embodiment, the configuration of the radio sound unit 200 is the same as that in FIG. In other words, the radio sound unit 200 according to the present embodiment includes a control unit 201, antennas 202 and 203, radio units 204 and 205, AIUs 209 and 210, amplifiers 211 and 212, speakers 213 and 214, and a microphone 215. The

  Further, the control unit 201 in the radio sound unit 200 includes a signal processing unit 206, an MPU 207, and a PLD 208 therein. In particular, in the present embodiment, the signal processing unit 206 in the control unit 201 has a function of calculating the received signal strength (RSSI) of each signal of the direct communication wave and the base station return communication wave and comparing the input levels. I have.

  The configuration of the wireless communication system is also assumed to be the same as that shown in FIG. That is, the wireless communication system includes a base station 101, mobile stations 102-1, 102-2,... 102-N.

  In the configuration of the wireless communication system and the configuration of the radio unit voice unit 200 as described above, particularly in the present embodiment, the base station 101 returns communication wave via the base station 101 within the operation area of the base station 101. When there are a plurality of mobile stations 102-1 to 102-N that are operated in a communication mode in which communication is performed in the communication mode and a communication mode in which communication is performed using direct communication waves without using the base station 101, for example, The signal processing unit 206 compares the received signal strengths (RSSI) of the two signals to reduce or mute the lower output level. The function of reducing or muting the output level can be arbitrarily selected.

  For example, the reception voice signal input from the antenna 202 is output to the speaker 213 via the radio unit 204, the control unit 201, the AIU 209, and the amplifier 211, and the reception voice signal input from the antenna 203 is controlled by the radio unit 205. In the case of a configuration that outputs to the speaker 214 via the unit 201, AIU 210, and amplifier 212, the received audio signal input from the antenna 202 and the antenna 203 is received by the signal processing unit 206 in the control unit 201. Each RSSI is calculated, and the input level is compared from each calculated value.

  As a result of this comparison, for example, when the input level on the antenna 203 side is small, the output level from the speaker 214 that outputs the audio signal input from the antenna 203 is reduced or muted. In this case, since the input level on the other antenna 202 side is large, the output level from the speaker 213 that outputs the audio signal input from this antenna 202 is left as it is or is amplified by the amplifier 211 and output from the speaker 213. . In this way, the output level with the smaller input level is reduced or muted.

  According to the second embodiment described above, direct communication is possible in a wireless communication system capable of receiving two signals of a direct communication wave and a base station return communication wave between wireless terminals and outputting sound from a speaker. Echo and howling by calculating and comparing the received signal strength (RSSI) of each of the wave and base station loopback communication wave signal and muting or weakening the sound output corresponding to the wave with the lower value (level) Since such an unpleasant phenomenon can be prevented, it is possible to ensure communication with good voice quality.

<Modification of the first and second embodiments>
As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

  For example, in the above description, it is assumed that there are two routes, that is, via the base station and direct communication. However, when there are N audio output devices, N-1 audio output control is included in the range of the present invention.

  Further, in FIG. 8, it is assumed that the output is based on different audio data from each of the two speakers. However, it is also included in the range of the present invention that a single speaker is used and the audio signal is synthesized and output by the signal processing unit 206.

  The present invention is limited to terminals belonging to a system such as a local government disaster prevention radio, and is assumed to be used in a system that uses both a direct communication wave and a base station loopback communication wave. However, the present invention is not limited to this, and may be used in other communication systems for the purpose of preventing the occurrence of echoes due to the identity of the data of the direct communication wave and the base station return communication wave.

101 ... base station, 102-1, 102-2, 102-N ... mobile station,
103, 103-1, 103-2, 103-3, 103-4, 103-5,
103-6 ... FL,
104, 104-2, 104-3, 104-4, 104-6 ... FH,
200: Radio unit, 201: Control unit, 202, 203 ... Antenna,
204, 205 ... wireless unit, 206 ... signal processing unit, 207 ... MPU,
208 ... PLD, 209, 210 ... AIU, 211, 212 ... Amplifier,
213, 214 ... Speaker, 215 ... Microphone, 300 ... Data frame,
302 ... Synchronization word, 303 ... Information symbol, 304 ... Individual information storage area,
305 ... Individual ID for mobile station, 306 ... Individual ID for base station.

Claims (2)

Two signals of a direct communication wave used for direct communication between wireless terminals and a base station loopback communication wave for performing relay communication between the wireless terminals via a base station are received and synthesized from different speakers or received signals. It is possible to output sound from one speaker, and when the base station receives sound data from one wireless terminal among a plurality of wireless terminals, the contents of the individual information storage area of the sound data are individually transmitted. replicate in the information storage area, by adding the ID of its own, the base station folding communication wave the transmission signal included in the individual information storage area of the transmission signal and the ID of the ID and its own said one radio terminal A wireless terminal in a wireless communication system that transmits from the base station as
A radio terminal in an individual information storage area included in signals of the direct communication wave and the base station return communication wave by demodulating a direct communication wave from another radio terminal and a base station return communication wave from the base station, respectively. If the IDs of the wireless terminals match, one audio output is muted or weak, and if the wireless terminal IDs do not match, both wireless outputs . A base station and a plurality of radio terminals, wherein the radio terminal is a direct communication wave used for direct communication with another radio terminal and a base station loopback communication wave that performs relay communication between the radio terminals via the base station. A wireless communication system capable of receiving two signals and outputting sound from different speakers or synthesizing received signals from one speaker,
When the base station receives voice data from one of the plurality of radio terminals, the base station copies the contents of the individual information storage area of the voice data to the individual information storage area of the transmission signal, and sets its own ID. by adding, sending from the base station and the ID of the ID and its own said one radio terminal, as the base station folding communication wave the transmission signal included in the individual information storage area of the transmission signal,
The other radio terminals of the plurality of radio terminals demodulate the direct communication wave from the one radio terminal and the base station return communication wave from the base station, respectively, so that the direct communication wave and the base station return When the IDs of the wireless terminals in the individual information storage area included in the communication wave signal are compared and the IDs of the wireless terminals match, one audio output is muted or weak, and the IDs of the wireless terminals do not match A wireless communication system characterized in that both are output as audio.

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