JP2001007787A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly transmit information from a transmission side to plural reception sides with satisfactory quality at conducting of 1:N radio communication. SOLUTION: At receiving of a transmission signal from a transmitting and receiving device 100, transmitting and receiving devices 101-10n detect the communication quality of the reception signal, and supply a reponse signal whose time length is made different according to the validity/invalidity of the detected communication quality to the transmitting and receiving device 100. When the time length of the response signal is long, the transmitting and receiving device 100 transmits the previously transmitted transmission signal again to the transmitting and receiving devices 101-10n.

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 wireless communication system that performs 1: N wireless communication at the same time.

[0002]

2. Description of the Related Art Conventionally, there has been known a radio communication system for simultaneously performing 1: N radio communication such as TV broadcasting and radio broadcasting. In such a wireless communication system, information to be provided by a transmitter (broadcasting station) is transmitted as a transmission signal, and the transmitted transmission signal is received by a receiver (TV or radio in each home). In such a case, the receiver provides the user with information corresponding to the received signal by amplifying and demodulating the received signal. Thus, in the above wireless communication system, the transmitter continues to transmit the signal regardless of the quality state of the signal received by the receiver.

[0003]

The signals received by the receiver have various communication qualities. In the above wireless communication system, if the transmitter continues to transmit a signal even though the communication quality of the received signal at the receiver is poor, the receiver provides information to be provided to the user with good quality to provide. You will not be able to do it. Therefore, the use of the above-described conventional wireless communication system is not appropriate in a situation in which predetermined information is to be reliably wirelessly communicated with high quality within a narrow range of about several tens of meters, such as in a train.

[0004] The present invention has been made in view of the above points, and has as its object to provide a radio communication system capable of quickly transmitting information from a transmitting side to a plurality of receiving sides with good quality.

[0005]

The above object is achieved by the present invention.
As described in the above, in a wireless communication system that performs 1: N wireless communication simultaneously, when a receiving side (10 ₁ to 10 _n ) receives a transmission signal from a transmitting side (10 ₀ ), the communication quality of the signal is Detecting means (step 84) for detecting
And response signal supply means (steps 86 and 88) for supplying response signals having different time lengths to the transmission side (10 ₀ ) in accordance with the detected communication quality.
0 ₀ ) on the receiving side (10) according to the time length of the response signal.
_The wireless communication system is characterized in that it has retransmission means (step 102 after a negative determination is made in step 110) for retransmitting the transmission signal with respect to ₁ to 10 _n ).

In the present invention, the receiving side (10 ₁ to 1)
0 _n ) receives the transmission signal from the transmission side (10 ₀ ), the communication quality of the signal is detected. Response signals having different time lengths according to the detected quality of communication quality are supplied from the receiving side (10 ₁ to 10 _n ) to the transmitting side (10 ₀ ). Then, the previously transmitted transmission signal is transmitted again from the transmitting side (10 ₀ ) to the receiving side (10 ₁ to 10 _n ) according to the length of the response signal. As described above, when the communication quality of the received signal is poor on the receiving side (10 ₁ to 10 _n ), the transmission signal transmitted once by the transmitting side (10 ₀ ) is retransmitted. The communication quality in (10 ₁ to 10 _n ) can be maintained satisfactorily. In the present invention, the transmitting side (1
0 ₀ ) and the plurality of receivers (10 ₁ to 10 _n ) are simultaneously performed, so that information is transmitted promptly. Therefore, according to the present invention, information to be provided can be promptly transmitted with good quality from the transmitting side (10 ₀ ) to each of the receiving sides (10 ₁ to 10 _n ).

[0007] The symbols in the parentheses are given for easy understanding, and are merely examples.

[0008]

FIG. 1 shows a communication mode of a wireless communication system according to an embodiment of the present invention. As shown in FIG.
Wireless communication system of the present embodiment, for example, the n + 1 composed of transceiver 10 ₀ to 10 _n. Hereinafter, the transmission / reception devices 10 ₀ to 10 _n are collectively referred to as the transmission / reception devices 10
It expresses. Each transmitting / receiving device 10 is connected to another transmitting / receiving device 10,
For example, bidirectional wireless communication is performed in a narrow area of about several meters to several tens of meters. In the following, for convenience, as a sender to provide information transmitting and receiving apparatus 10 _0, The transmitting and receiving apparatus 10 ₁
Explaining to 10 _n as a receiver for receiving the information.

The transmitting / receiving device 10 has an antenna 14 for transmitting / receiving signals. Transceiver 10 _0, transmits from the antenna 14 converts the information to be provided to the appropriate signal, the transceiver device 10 ₁ to 10 _n receives the response signal to be transmitted. In addition, the transmitting and receiving devices 10 ₁ to 10 _n
Is a signal transceiver 10 ₀ is transmitted with received by the antenna 14, detects the communication quality of the signal as described later when it receives a signal from the transceiver 10 _0, when the communication quality is good the short response signal in time length T _1, whereas, when the communication quality is poor is a long response signal in time length T _2, is transmitted from the antenna 14 to the transceiver 10 _0.

FIG. 2 shows a configuration diagram of the transmission / reception device 10 of the present embodiment. As shown in FIG. 2, the transmission / reception device 10 has a memory 20 in which information to be provided is stored. An encoder / framer 22 is connected to the memory 20. A control unit 40 is connected to the encoding / framing unit 22. The controller 40 controls the encoder / framer 2 when the information stored in the memory 20 is to be provided.
2 is supplied with a control signal. The encoder / framer 22 receives the control signal from the control unit 40,
The information stored in the memory 20 is encoded and framed while being divided into predetermined lengths.

The encoder / framer 22 includes a modulator 2
4, a power amplifier 26 is connected. The modulator 24 modulates and outputs the signal encoded and framed by the encoder / framer 22. Power amplifier 2
6 amplifies and outputs the modulated signal modulated by the modulator 24. The antenna 14 is connected to the power amplifier 26 via a changeover switch 28. Changeover switch 2
Reference numeral 8 denotes a switch for switching between a transmission mode and a reception mode. In the above configuration, the information stored in the memory 20 is converted into a predetermined signal and transmitted from the antenna 14 at a predetermined timing.

The changeover switch 28 is connected to the antenna 14.
Through a low-noise amplifier (hereinafter abbreviated as LNA) 30
Is connected. The LNA 30 has a function of suppressing noise superimposed on the received signal when a signal is received by the antenna 14 in a state where the changeover switch 28 is switched to the reception mode. LNA30 has
A decoding / deframing unit 34 is connected via a demodulator 32. The demodulator 32 demodulates the signal whose noise has been cut by the LNA 30 and outputs the demodulated signal. The decoder / deframer 34 decodes and deframes the signal output from the demodulator 32. A memory 36 is connected to the decoding / deframing unit 34. The memory 36 stores information decoded by the decoding / deframing unit 34. According to the above configuration, when a signal transmitted as information to be provided by another transmission / reception device 10 is received by the antenna 14, the signal is converted into information and stored in the memory 3.
6, such information is provided.

The decoder / deframer 34, the encoder / framer 22 and the power amplifier 26 are each connected to a control unit 40. When the antenna 14 receives a signal transmitted as information to be provided by the other transmitting / receiving device 10, the control unit 40 determines whether the communication quality of the decoded and deframed signal is good or not, It is determined whether or not the error has occurred. And
Short response signal of time length T ₁ when it is determined that no error has occurred, whereas, long response signal when determining that an error has occurred the time length T ₂ is the other transceiver 1
A control signal is supplied to the power amplifier 26 so that the control signal is supplied to 0. In this case, the antenna 14 outputs a response signal having a longer or shorter time length T ₁ or T ₂ .

The exit side of the LNA 30 is connected to the control unit 40. When the response signal transmitted by the other transmission / reception device 10 is received by the antenna 14, the control unit 40
The time length T of the response signal is detected by monitoring the carrier of the signal output from 30, and the length of the time length T is determined. When the time length T is short, it is determined that no error has occurred in the transmission and reception of the signal in the other transmission / reception device 10, and the encoding / frame processing is performed to provide the next information stored in the memory 20. The control signal is supplied to the converter 22. On the other hand, when the time length T is long,
The other transmission / reception device 10 determines that an error has occurred in the transmission / reception of the signal, and supplies a control signal to the encoding / framing device 22 and the power amplifier 26 in order to provide the previously provided information again.

A display section 48 is connected to the control section 40. Control unit 40, when the information stored in the memory 20 does not receive a response signal from the transceiver 10 ₁ to 10 _n after transmission, so that the display no response is made by the transceiver 10 side ₀ A control signal is supplied to the display unit 48. Next, transmission and reception of signals in the wireless communication system according to the present embodiment will be described with reference to FIGS.

FIG. 3 shows a transmitting / receiving apparatus 10 according to this embodiment.
₀ and shows a diagram for explaining the exchange of signals between the transceiver device 10 ₁ to 10 _n. FIG. 3A shows the transmission / reception device 10.
₀ indicates a time change of the signal to be transmitted. 3 (B) shows a time variation of the signal transmitting and receiving device 10 ₁ sends. Further, FIG. 3 (C) shows a time variation of the signal transmitting and receiving apparatus 10 ₂ is transmitted.

[0017] As shown in FIG. 3 (A), transceiver 10 ₀
Divides information to be provided into units of about several tens of bytes and transmits the information at a constant period. As described above, the transceiver 10 ₀ and the transceiver device 10 ₁ to 10 _n, performs transmission and reception of signals between relatively short distance. Therefore, signals transmitted from the transmitter-receiver unit 10 ₀ is approximately simultaneously received in each transceiver device 10 ₁ to 10 _n. Signal transmitted from the transmitting and receiving apparatus 10 _0,
For example, the frame number, data content,
And parity bits. Transceiver 10 _1, 10 _2, every time the signal from the transceiver 10 ₀ is transmitted, the communication quality of the signal, i.e., detects whether an error in the signal being generated by a parity check or the like. When it is determined that no error has occurred in the signal, a response signal of a predetermined time length T ₁ (for example, 10 msec) is transmitted. On the other hand, when it is determined that an error has occurred in the signal, the time length T ₁ is determined. A response signal having a time length T ₂ (for example, 20 msec) longer by a predetermined time than ₁ is transmitted.

[0018] As shown in FIG. 3 (B) and (C), after the signal of the data D ₁ from the transceiver 10 ₀ is transmitted, at time t _1, the signal transmitting and receiving apparatus 10 ₁ time length T ₁ is together are output, from the transceiver 10 ₂ are output signals of the time length T _2. In this case, transceiver 10 ₀ determines that the time length T of a signal from one of the transmitting and receiving apparatus 10 _1, 10 ₂ is long, transceiver 10 ₁
Or it is determined that an error has occurred with respect to the sending and receiving of signals at 10 _2. Then, the signal of the previously transmitted data D ₁ is transmitted again to the transmission / reception devices 10 ₁ and 10 ₂ .

[0019] After the signal of the data D ₁ from the transceiver 10 ₀ is retransmitted, in time t _2, the transceiver 10 ₁
And 10 ₂ output a signal having a time length T ₁ . In this case, transceiver 10 ₀ determines the time length of the signals from all the transceiver 10 _1, 10 ₂ is short,
It is determined that no error has occurred in signal transmission / reception in any of the transmission / reception devices 10 ₁ and 10 ₂ . Thereafter, it transmits the next new data D ₂ of the data D ₁ to the transceiver apparatus 10 _1, 10 _2.

[0020] Figure 4, so as to achieve the above-mentioned functions, transceiver 10 ₁ to 10 in the wireless communication system of this embodiment
4 shows a flowchart of an example of a process executed by an _n control unit 40. The process shown in FIG. 4 is repeatedly started each time the process is completed. When the routine shown in FIG. 4 is started, first, the process of step 80 is executed. Step 8
In 0, it determines whether it has received a signal transmitted from the transmitting and receiving apparatus 10 _0. The process of step 80 is repeatedly executed until the above condition is satisfied. As a result, if it is determined that a signal has been received from the transceiver 10 _0, the process of step 82 is executed.

In step 82, the parity check of the signal received in step 80 is performed. In step 84, as a result of the parity check performed in step 82, it is determined whether or not the received signal is normal. As a result, if the parity is normal, the process of step 86 is executed next. On the other hand, if the parity is abnormal, the process of step 88 is executed next.

[0022] At step 86, it performs the processing of transmitting the response signal of the time length T ₁ with respect to transceiver 10 _0.
In step 88, the time length T ₂ longer than the time length T ₁
Executing a process of transmitting the response signal with respect to transmitting and receiving apparatus 10 _0. According to the above processing, the transmission / reception device 1 sends response signals having different time lengths depending on the presence or absence of an error in the received signal
0 ₀ can be supplied to.

FIG. 5 shows a transmitting / receiving apparatus 1 in the wireless communication system of the present embodiment to realize the above-described functions.
0 ₀ control unit 40 of an example flowchart of the processing executed. The process shown in FIG. 5 is repeatedly started each time the process ends. When the processing shown in FIG. 5 is executed,
First, the process of step 100 is performed. Step 10
At 0, it is determined whether or not the present time is the provision timing of the information stored in the memory 20. This step 1
The process of 00 is repeatedly executed until it is determined that the above condition is satisfied. Then, when it is determined that the information providing timing has been reached, the process of step 101 is executed next.

In step 101, a process for encoding and framing information stored in the memory 20 is executed. In step 102, a process of transmitting the signal framed in step 100 from the antenna 14 is executed. In step 104, after the transmission of the signal is completed, the transmission and reception device 10
_It is determined whether response signals from ₁ to 10 _n have been received. If it is determined that no response signal has been received, the process of step 106 is performed next. On the other hand, when it is determined that the response signal has been received, the process of step 108 is executed next.

In step 106, a no-response display is made.
Command signal to the display unit 48 as described above. Book
When the processing in step 106 ends, the current routine ends.
Is completed. In step 108, the time length T of the response signal is calculated.
To detect. At step 110, at step 108
The detected time length T is a predetermined value T₀Whether it is shorter than
Determine. The predetermined value T₀Is the transmitting and receiving device 10₁-10
_nT to determine the state of the response signal output from₁
<T₀<T_Two, For example, 15 m
It is stored in advance in sec. As a result of the above, T <T ₀But
If the condition is satisfied, the signal transmission / reception
It can be determined that no error has occurred in communication. This place
In order to provide new information,
10₀It is appropriate to transmit to the transmitting / receiving device 10 from
It is. Therefore, T <T₀If it is determined that
Then, the process of step 112 is executed.

In step 112, a process for resetting the counter CNT to "0" is executed. The counter C
NT is a counter for counting the number of times that the condition (T <T ₀ ) in step 110 is not satisfied. When the process of step 112 is completed, the current routine is completed. On the other hand, if T <T ₀ does not hold in step 110, any of the transmitting / receiving devices 10
Thus, it can be determined that an error has occurred in signal transmission / reception. In this case, it is appropriate to transmit the signal transmitted in step 102 immediately before the execution of the processing in step 110 to the transmitting / receiving apparatus 10 again. Therefore,
If it is determined that T <T ₀ does not hold, the process of step 114 is executed next.

In step 114, the counter CNT is set to 1
Execute the process of incrementing only. Step 11
In 6, the counter CNT is determined whether or not has reached a predetermined value CNT _0. The predetermined value CNT ₀ is the number of signal retransmissions, and is set to, for example, three or four times. CN
If T ≧ CNT ₀ is not satisfied, signal retransmission is allowed. Therefore, when such a determination is made, the process of step 102 is executed again. On the other hand, CNT
When ≧ CNT ₀ is satisfied, it is desirable not to retransmit the signal in order to prevent a longer communication time. Therefore, if such a determination is made, then step 1
After the processing of step 12 is executed, the current routine ends.

According to the above-mentioned process, transceiver 10 ₁ -
If the time length of the response signal output from 10 _n is short, new information can be transmitted sequentially, and if the time length of the response signal is long, the previously transmitted information can be retransmitted. That is, according to the present embodiment, the transmitting / receiving device 1
0 ₀ If it is determined that no error has occurred with respect to the sending and receiving of also the signal to any of the transceiver device 10 ₁ to 10 _n, sequentially transmits the information toward the transceiver 10 ₀ to the transceiver device 10 ₁ to 10 _n And transmission / reception device 1
0 ₀ If it is determined that an error has occurred in any of the transceiver device 10 ₁ to 10 _n, it is possible to transmit the same information again. Therefore, according to this embodiment, even if an error occurs with respect to the sending and receiving of signals in the transmission and reception device 10 ₁ to 10 _n, it is possible to maintain good quality of the information to be provided.

In this embodiment, the transmitting / receiving device 10₀Is
Information to be provided to each transmitting and receiving device 10 ₁-10_nAgainst
Send all at once. Therefore, the wireless communication system of the present embodiment
According to, the information to be provided is quickly transmitted and received with good quality
It is possible to transmit to the device 10. Ma
According to the above processing, the transmitting / receiving device 10₀Send and receive from
Apparatus 10₁-10_nLimit the number of signal retransmissions for
Can be For this reason, according to the present embodiment,
It is possible to prevent the time from becoming unduly long
You.

In the above embodiment, the transmission / reception device
10₁-10_nIs the transmitting and receiving device 10 ₀The transmitted signal from
After receiving, it checks whether there is an error in the signal.
"Quality detection means" described in the claim by detecting
Has a different response time depending on whether there is an error in the signal.
Signal transmitting / receiving device 10₀Output to
"Response signal supply means" described in the request
And the transmission / reception device 10₀Is the transmitting and receiving device 1
0₁-10_nTime length of response signal output from
If it is determined that the time length is long,
By transmitting the communication signal again to the transmission / reception device 10,
"Retransmission means" described in the claims is realized.

In the above embodiment, a plurality of (n + 1) transmitting / receiving apparatuses 1 each capable of providing information are provided.
However, the present invention is not limited to this, and one transmitting apparatus (master station) for providing information and a plurality of receiving apparatuses (for receiving information) are provided. It is also possible to apply to wireless communication with the slave station.

[0032]

As described above, according to the first aspect of the present invention, information from a transmitting side can be quickly transmitted to a plurality of receiving sides with good quality.

[Brief description of the drawings]

FIG. 1 is a communication form of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a transmission / reception device of the present embodiment.

FIG. 3 is a diagram for explaining signal transmission / reception between transmission / reception devices in the present embodiment.

FIG. 4 is a flowchart illustrating an example of a process performed by a receiving-side control unit that receives provision of information in the embodiment;

FIG. 5 is a flowchart illustrating an example of a process executed by a control unit on the transmission side that provides information in the embodiment.

[Explanation of symbols]

10 ₀ ~10 _n transmitting and receiving device

Claims (1)

[Claims] 1. A wireless communication system for simultaneously performing 1: N wireless communication, wherein a receiving side detects a communication quality of a transmission signal from a transmitting side when the transmission signal is received from the transmitting side, and the detected communication. Response signal supply means for supplying a response signal having a different time length to the transmission side according to the quality, wherein the transmission side retransmits the transmission signal to the reception side according to the time length of the response signal. A wireless communication system, comprising: