JP2000269852A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent crosstalk in a base station by limiting call transmission by a plurality of slave stations in a radio communication system consisting of the one base station and a plurality of the slave stations. SOLUTION: Prior to transmission of voice data from a slave station side to a base station, a control frame signal is sent/received between both the stations first to set up communication connection. Then a control frame signal generating section 15 of the slave station side generates a control frame signal including own station number data and data to obtain permission of transmission start, and an antenna 19 transmits the signal to the base station. The base station receives this transmission signal, and a data discrimination section 44 discriminates transmission contents. After the discrimination, a control frame signal generating section 35 of the base station generates the control frame signal including data denoting transmission permission and the station number data of the slave station and transmits the control signal to the slave station. A data discrimination section 24 of the slave station discriminates transmission contents and confirms the station number data and the transmission permission. The slave station transmits voice data after the step above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly, to a restriction on a local station side transmission in a digital communication system formed by one base station and a plurality of child stations.

[0002]

2. Description of the Related Art There are various types of radio communication systems. One of the conventional radio communication systems is a radio communication system shown in FIG. In addition,
Hereinafter, the slave station will be described as a mobile station. As shown in the figure, this wireless communication system is formed by one base station 51 and a plurality of mobile stations 52 to 54, and each mobile station and the base station 51 use a single carrier f1 to transmit a voice signal. It performs wireless communication. The modulation method is analog modulation. Since the carrier is single (f1), one mobile station is connected to the base station 51.
To send a message, you need to press the talk button.
While the talk button is pressed, the channel is occupied by the mobile station. Therefore, the base station can transmit its own station only after confirming that the mobile station has finished transmitting.

[0003]

However, in the radio communication system shown in FIG. 4, when a plurality of mobile stations transmit simultaneously without confirming the communication state of another mobile station (this case actually occurs). ), The base station receives all signals in a state of interference. Therefore, the demodulated and reproduced sound naturally has a state in which a plurality of sounds are interfered. However, since the modulation method of the transmission signal is an analog method as described above, it was possible to discriminate the sound of a specific mobile station from the interference state and listen to it by concentrating attention. As described above, the radio communication system shown in FIG. 4 has a drawback of interference.

[0004] On the other hand, it is well known that in the field of communication technology, a conventional analog system is shifting to a digital system. The wireless communication system shown in FIG. 4 is no exception. When this digitization is simply applied to the wireless communication system shown in FIG. 4, it is possible to listen to the sound of a specific mobile station from among the analog systems even in the interference state. However, there is a problem that the audio is not reproduced at all. This is because when the digital signal in the interference state is D / A converted and converted back to an analog signal, the signal becomes completely different. Therefore, it is desired that the radio communication system shown in FIG. 4 can be digitized with some measures introduced to improve the problem of interference. The present invention has been made from this point of view, and is a digital system formed by one base station and a plurality of mobile stations, which has been digitized by improving the interference by automatically limiting the transmission on the mobile station side. The purpose of the present invention is to provide a wireless communication system.

[0005]

SUMMARY OF THE INVENTION The present invention provides a control frame signal generating means for generating a control frame signal which is a transmission frame for communication connection with a base station, and a communication frame signal which is a transmission frame of digital voice data. Communication frame signal generation means for generating a frame signal; transmission means for digitally modulating the control frame signal and the communication frame signal to transmit the carrier signal at a predetermined frequency; and reception for receiving a signal from the base station Means, a slave station comprising data discriminating means for discriminating data content of a signal received by the receiving means, a receiving means for receiving a signal from the slave station, and data of a signal received by the receiving means. Data determining means for determining the content, and a control frame signal for generating a control frame signal which is a transmission frame for communication connection with the slave station Generating means and a base station comprising a transmitting means for digitally modulating with the control frame signal and transmitting the carrier signal at a predetermined frequency.When transmitting voice data from the slave station to the base station, It is an object of the present invention to provide a wireless communication system in which the control frame signal is first transmitted and received between both stations, and after establishing a communication connection, the voice data is transmitted.

The transmission and reception of the control frame signal between the two stations may include a transmission start permission request and a permission response to the request.

The control frame signal in the slave station includes data relating to its own station number and data for requesting permission to start transmission, and the control frame signal in the base station includes a control frame signal of the slave station received. Includes data related to station numbers and data related to transmission permission or non-permission.

The data discriminating means in the base station discriminates whether or not the data pertaining to the station number from the slave station is data for which permission to start transmission is provided. It is determined whether the data of the station number from the station is its own data and whether or not the transmission is permitted.

The determination by the data determination means is performed based on data of a parameter period forming one period of the control frame signal.

Further, the base station is provided with a communication frame signal generating means for generating a communication frame signal which is a transmission frame of the digital voice data, and the base station receives the control frame signal together with the control frame signal from the slave station. Is transmitted.

Further, the frequency of the carrier signal on the mobile station side and the frequency of the carrier signal on the base station side are set to different frequencies.

Further, the mobile station is provided with an alarm generating means, and when the data discrimination means does not determine the data relating to the own station number, an alarm is generated by the alarm generating means. The alarm is a warning light or an alarm sound.

Further, a system configuration is made up of one base station and a plurality of slave stations.

[0014]

Embodiments of the present invention will be described below with reference to the drawings based on embodiments. FIG. 1 is an explanatory diagram of a system configuration of a wireless communication system according to the present invention, and FIG. 2 is a mobile station (slave station) in a wireless communication system according to the present invention.
FIG. 3A is a main block diagram showing an embodiment of each of the base station (FIG. 2B) and FIG. 3 is an explanatory diagram relating to FIG.
First, a system configuration of a wireless communication system according to the present invention will be described with reference to FIG. As shown, the wireless communication system according to the present invention is formed by one base station 1 and a plurality of mobile stations 2 to 4 as in FIG. However, as the carrier signal, two waves of a carrier signal of a frequency f1 used for transmission from each mobile station to the base station 1 and a carrier signal of a frequency f2 used for transmission from the base station 1 to each mobile station are used. use.
The reason for using these two waves will be described later. The modulation method is digital modulation, and is a wireless communication system mainly for transmitting and receiving voice signals.

Next, the base station 1 and each of the mobile stations 2 to 4 in FIG.
Will be described with reference to FIGS. 2 and 3.
Each of the mobile stations 2 to 4 has the same configuration. In the mobile station shown in FIG. 2A, reference numeral 11 denotes a microphone which is used when transmitting voice to a base station. Reference numeral 12 denotes an amplification unit that amplifies an audio signal from the microphone 11 and the like. Reference numeral 13 denotes an encoding processing unit, which converts an analog audio signal from the amplifying unit 12 into digital audio data (A / D conversion) and performs data compression processing. Reference numeral 14 denotes a communication frame signal generation unit which generates a communication frame signal of a predetermined format including digital voice data from the encoding processing unit 13. This format example will be described later. Reference numeral 15 denotes a control frame signal generation unit, which is a transmission frame used for communication connection with the base station 1 before transmitting the communication frame signal. An example of the format of this frame will also be described later. Reference numeral 16 denotes a digital modulation unit [for example, QPSK (quadrature modulation) or the like], which performs digital modulation using the control frame signal and the communication frame signal.

Reference numeral 17 denotes a transmission unit, which amplifies the signal from the digital modulation unit 16 to the power required for transmission, and transmits the signal with a carrier having a frequency f1. Reference numeral 18 denotes an antenna switching circuit that switches the antenna 19 for both transmission and reception. Reference numeral 20 denotes a reception demodulation unit which receives a signal from the base station 1 and digitally demodulates the signal. Reference numeral 21 denotes a decoding processing unit which performs data expansion and conversion (D / A conversion) of the digital signal demodulated by the reception demodulation unit 20 into an analog signal. Reference numeral 22 denotes an amplification unit that amplifies the level of the analog signal from the decoding processing unit 21. Reference numeral 23 denotes a speaker that is driven by a signal from the amplifier 22 and reproduces sound from the base station. Reference numeral 24 denotes a data discriminating unit, which discriminates data (station number data) relating to the station number of the partner mobile station and the contents of the transmission data based on the signal demodulated by the reception demodulation unit 20.

Reference numeral 25 denotes an alarm generating unit which generates an alarm when the data discriminating unit 24 does not discriminate its own station number data and notifies the operating person. The form of the alarm is a warning light such as an LED or a warning sound such as a buzzer. Reference numeral 26 denotes a control unit which controls the communication frame signal generation unit 14, control frame signal generation unit 15, digital modulation unit 16, antenna switching circuit 18, data discrimination unit 24, alarm generation unit 25, and the like. On the other hand, the base station shown in FIG. 2B has substantially the same configuration as that of the mobile station except that an alarm generation unit is not provided in a block diagram, and the function of each block is also the same. However, the frequency of the carrier signal used in the transmitting section 37 is f2 different from that of the mobile station. Therefore, each functional block is given only a reference numeral, and a description of the function is omitted.

Next, the speech frame signal and the control frame signal will be described. These formats are common to the base station and the mobile station, but for convenience of explanation, the description will be made based on the mobile station side. First, FIG. 3A shows a format example of a communication frame signal. In FIG. 3A, “P” is a preamble, which is a period provided for stabilizing a receiving circuit (for example, an AGC circuit) of a partner station at the start of communication. "TCH" (Talk Channel)
Is a period of the audio data from the encoding processing unit 13, and is made by dividing the audio data into a predetermined number of bits. The “parameter” is generally a period during which information other than various data and audio data is inserted. "SW" (Sync
h Word) is a synchronization word, and is a data period for synchronizing communication.

Next, FIG. 3B shows an example of the format of the control frame signal. As shown, in addition to the above-mentioned preamble (P), parameters, and synchronization word (SW),
"G" is included. This “G” is a guard period, which is a period for preventing overlap with the next frame due to, for example, a delay during air propagation. The control frame has two parameter portions as shown in the figure. In the present invention, the parameters are used. The numbers in parentheses in FIGS. 3A and 3B are examples of the number of bits. FIG. 3C shows a specific configuration example of the above parameters. In the figure, “A” represents a frame type, which is, for example, 1-bit data, and “1” represents a control frame (CF) described later,
If it is “0”, it indicates that it is a communication frame (TF).

"B" represents a frame number, which is, for example, 2-bit data, and the frame number is represented by these 2 bits. “C” represents a station number, that is, a type of a mobile station or a base station, which is represented by, for example, 16-bit data. “D” is a data period for communication control, which is, for example, 1-bit data. In a mobile station, “1” indicates “transmission start”, “0” indicates “non-transmission”,
In the base station, "1" indicates "transmission permitted" and "0" indicates "transmission non-permitted". "E" is the other period,
It is used for transmission of various data and information other than voice. In particular, the base station inserts the station number data of the mobile station received during this period.

Next, a communication procedure under the configuration described above will be described with reference to FIG. The description here is based on the assumption that only the mobile station a2 has originated a call, and the communication between the mobile station a2 and the base station 1 will be described as an example. Mobile station a
2 is the audio data from the microphone 11 (call frame signal)
Prior to the transmission of (1), a control frame signal is transmitted (called) (CF1) to secure a communication connection with the base station 1. At this time, “C” in FIG. 3C (parameter) is the station number data specifying the mobile station a2, and “D” sets the data to “1” to indicate “transmission start”. The control frame signal is generated by the control frame signal generation unit 15 (control frame signal generation means) under the control of the control unit 26, and the digital modulation unit 16, the transmission unit 17 (carrier frequency f1), and the antenna switching circuit The signal is transmitted from an antenna 19 via 18 (transmission means). During this transmission, the antenna switching circuit 18 is set on the transmission side (a side) by the control unit 26. Further, the own station number data is stored in a memory unit (not shown) of the control frame signal generation unit 15 in advance.

In response to the call from mobile station a2, base station 1 receives the transmission signal via antenna 39. At the time of this reception, the control unit 45 sets the antenna switching circuit 38 to the reception side (b
Side). The reception signal is input to the reception demodulation unit 40 via the antenna switching circuit 38, and the data related to the control frame signal is demodulated (receiving means). In this case, from the above assumption, the transmitting station is only the mobile station a2,
Since there is no interference with other mobile stations, data demodulation is performed normally. The demodulated data is input to the data discrimination unit 44. The data determination unit 44 determines the type (station number) and transmission content of the mobile station based on the data of the "C" and "D" parts of the parameters in the control frame signal. Accordingly, it is determined that the call destination is the mobile station a2 and that the request is for "transmission start".

Following this determination, the base station 1 transmits a control frame signal (CF2). At this time, FIG.
Data for identifying the base station 1 is inserted into “C” of (parameter), transmission is permitted by changing data of “D” to “1”, and the station of the mobile station a2 determined by the data determination unit 44 is defined as “E”. Insert number data. If the transmission is not permitted, the data of "D" is set to "0". The control frame signal is supplied to the control frame signal generator 35 under the control of the controller 45.
(Control frame signal generating means), and transmitted from an antenna 39 via a digital modulator 36, a transmitting section 37 (carrier frequency f2) and an antenna switching circuit 38 (transmitting means). During this transmission, the antenna switching circuit 38 is set on the transmission side (a side) by the control unit 45.

The transmission signal is received by the mobile station a 2 via the antenna 19. At the time of this reception, the control unit 26 sets the antenna switching circuit 18 on the reception side (b side). The reception signal is input to the reception demodulation unit 20 via the antenna switching circuit 18, and the data related to the control frame signal is demodulated (receiving means). In this case, data demodulation is performed normally because there is no interference problem as described above. The demodulated data is input to the data discrimination unit 24. The data discriminating unit 24 discriminates the station number and the transmission content based on the data of the parameters "C", "D" and "E" in the control frame signal. As a result, the destination is the base station 1, and
It is determined that the station number data of the mobile station is its own and that it is a response of “transmission allowed”. With this determination, the communication connection between the mobile station a2 and the base station 1 is confirmed, and according to the confirmation, the mobile station a2 starts transmitting a communication frame signal (TFu) including voice data. The communication frame signal (TFu) is generated by the communication frame signal generator 14 under the control of the controller 26 (communication frame signal generator).

The base station 1 transmits the communication frame signal (TF
u) (reception demodulation unit 40), and a decoding processing unit 41
Sound is output from the speaker 43 via the amplifying unit 42. Also,
The demodulated speech frame signal has the same data TFu '
Send as This transmission signal is a communication frame signal on the base station 1 side. The purpose of transmitting the TFu 'is to enable the other mobile station to recognize that the base station 1 is currently communicating with the mobile station a2 and that the communication content is recognized. This call frame signal (TFu ')
Is generated by the communication frame signal generation unit 34 using the signal from the reception demodulation unit 40 under the control of the control unit 45 (communication frame signal generation means). When voice data for a response to the reception is required, the base station 1 transmits the TFu 'and then transmits it as TFd (communication frame signal). The mobile station a2 receives the above-mentioned communication frame signal (TFd).
Is received and demodulated (reception demodulation unit 20), and decoding processing unit 21
The sound is output from the speaker 23 via the amplifier 22. Or later,
Transmission and reception of audio data are performed.

As described above, prior to the transmission of the original voice data, as shown in FIG. 3 (D), after the process of returning the own station number data through the process of CF1 → CF2 (hereinafter referred to as connection confirmation). The original voice data is transmitted. In other words, voice data cannot be transmitted without going through this connection confirmation process. In the above description, it is assumed that only the mobile station a2 has originated a call. On the other hand, when a call from another mobile station (for example, mobile station b3) is also generated, the operator of mobile station b3 is currently connected to base station 1 and mobile station a2.
It can be confirmed from the speaker's voice that communication is being performed with the device, and it can be recognized that a call (CF1) cannot be made. That is, FIG.
If (A) is the mobile station b3, the station number data determined by the data determination unit 24 is not its own. As a result, the control unit 26 cannot make a call (CF1) and forcibly ends the transmission control. In addition, each mobile station has a data discriminator 24.
If the transmission data from the base station 1 is not determined in step (1), a call (CF1) can be made. Therefore, even if a certain mobile station originates a call, if the base station 1 cannot normally receive the transmission signal due to interference or deterioration of the radio wave propagation state, the base station 1 responds to the CF1 (CF1).
2) is not transmitted, so that the calling mobile station cannot of course receive it and cannot confirm its own station number data. This forcibly ends the transmission control.

As described above, the transmission restriction is imposed on the mobile station, and the interference at the base station 1 is greatly reduced. If the connection with the base station 1 is not possible, that is, if the data discrimination unit 24 cannot discriminate the own station number data, the control unit 26 activates the alarm generation unit according to the discrimination, and issues a warning light such as an LED or a buzzer. An alarm such as an alarm sound is generated. Next, the carrier frequency (f
The reason why 1) and the carrier frequency (f2) of the base station are different from each other will be described. As described above, the mobile station and the base station 1
Means that it is necessary to go through a connection confirmation process between CF1 and CF2, but if there is a call from another mobile station at the same timing transmitted from the base station 1 to a certain mobile station, the frequency of both transmission signals will be In the same case, the former mobile station is in a state where the received signal is in a state of interference, which hinders the accurate progress of the connection confirmation process. In order to prevent this, the carrier frequency is divided into f1 and f2. However, when this interference is tolerated, the carrier frequency may be the same.

[0028]

As described above, according to the present invention, in a radio communication system formed by one base station and a plurality of mobile stations, a base station is controlled by a control frame signal prior to transmission of original voice data. Establishes a communication connection with the station, transmits voice data after establishing the communication connection, and stops mobile stations that cannot establish a communication connection.This greatly improves interference at the base station compared to the conventional analog method. In addition, digital communication with a plurality of mobile stations using two carrier frequencies can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a system configuration of a wireless communication system according to the present invention.

FIG. 2 is a main block diagram showing one embodiment of each of a slave station (mobile station) (FIG. A) and a base station (FIG. B) in the wireless communication system according to the present invention.

FIG. 3 is an explanatory diagram related to FIG. 2;

FIG. 4 is an explanatory diagram of a system configuration of a conventional wireless communication system.

[Explanation of symbols]

 1,51 Base station 2,3,4,52,53,54 Slave station 11,31 Microphone 12,22,32,42 Amplifying unit 13,33 Encoding processing unit 14,34 Communication frame signal generation unit 15,35 Control frame signal generator 16, 36 Digital modulator 17, 37 Transmitter 18, 38 Antenna switching circuit 19, 39 Antenna 20, 40 Reception demodulator 21, 41 Decoding processor 23, 43 Speaker 24, 44 Data discriminator 25 Alarm generator 26, 45 Controller

Claims (10)

[Claims] 1. A control frame signal generating means for generating a control frame signal which is a transmission frame for communication connection with a base station, and a communication frame for generating a communication frame signal which is a transmission frame of digital voice data. Signal generating means, transmitting means for digitally modulating the control frame signal and the communication frame signal and transmitting the carrier with a predetermined frequency carrier, receiving means for receiving a signal from the base station, and receiving by the receiving means A slave station comprising data discriminating means for discriminating the data content of the received signal, receiving means for receiving a signal from the slave station, and data discriminating means for discriminating the data content of the signal received by the receiving means. A control frame signal generating means for generating a control frame signal which is a transmission frame for communication connection with the slave station; A base station comprising a transmitting means for digitally modulating with a frame signal and transmitting the carrier signal at a predetermined frequency, and when transmitting voice data from the slave station side to the base station, first, between the two stations. A wireless communication system, wherein the voice data is transmitted after transmitting and receiving the control frame signal and establishing a communication connection. 2. The wireless communication according to claim 1, wherein the transmission and reception of the control frame signal between the two stations comprises a request for a transmission start permission and a permission response to the request. system. 3. The control frame signal in the slave station includes data relating to its own station number and data for requesting permission to start transmission, and the control frame signal in the base station includes the received control frame signal. 2. The wireless communication system according to claim 1, wherein data related to a station number of the slave station and data related to transmission permission or non-permission are included. 4. The data discriminating means in the base station,
The data relating to the station number from the slave station is determined as to whether the data is a request for permission of transmission start and the data determination means in the slave station determines that the data relating to the station number from the base station is its own data And determining whether the transmission is permitted or not.
A wireless communication system as described. 5. The radio communication system according to claim 4, wherein the discrimination by said data discriminating means is performed based on data of a parameter period forming one period of said control frame signal. 6. A communication frame signal generating means for generating a communication frame signal, which is a transmission frame of digital voice data, in said base station, and said base station receives a control frame signal from said slave station together with said control frame signal. 2. The wireless communication system according to claim 1, wherein said voice data is transmitted. 7. The wireless communication system according to claim 1, wherein a frequency of the mobile station side carrier signal and a frequency of the base station side carrier signal are different from each other. 8. The mobile station, wherein an alarm generating means is provided, and when the data discrimination means does not determine the data relating to the own station number, an alarm is generated by the alarm generating means. Item 2. The wireless communication system according to Item 1. 9. The wireless communication system according to claim 4, wherein the alarm is a warning light or an alarm sound. 10. The wireless communication system according to claim 1, comprising one base station and a plurality of slave stations.