JPH06350605A - Line connection device for data transmission - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency when an error takes place by allowing a master station and a slave station to use a timer respectively and applying time division to the interval of transmission and reception to take synchronization for each station. CONSTITUTION:Each of a master station 1 and slave stations 21-23 is respectively provided with a timer counting time for synchronization with time division. When an error takes place in the slave station 22, since no connection acknowledge signal is sent to the master station 1 between prescribed times t2 and t3 of the timer, no carrier is in existence between the times t2 and t3 of the timer, the master station 1 and the slave stations 21, 23 discriminate it that the error takes place in the slave station 22 to send the connection acknowledge signal because no carrier is in existence. Then the master station 1 transits to the re-transmission state of a connection request signal and the slave stations 22-23 transit to the standby state from the master station 1. That is, when the master station 1 and the slave stations 21-23 make carrier sense and receive no connection acknowledge signal, it is discriminated to be the occurrence of an error and the master station 1 sends again the connection request signal, then the time for the retransmission of the connection request signal is decreased and the transmission efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission line connection device comprising one master station and a plurality of slave stations, and performing data transmission between the master station and the slave stations.

[0002]

2. Description of the Related Art FIG. 7 shows one master station 1 and a plurality of slave stations 2 (2
_{1 to} 2 _n ) and shows a schematic system configuration diagram for wirelessly transmitting and receiving data between the master station 1 and the slave station 2. For example, in a specific low power radio station, which is composed of a master station 1 and a slave station 2, an MCA (multi-channel access) method for capturing a plurality of communication channels is used. The MCA system is composed of, for example, one control channel and a plurality of communication channels. When the calling side (master station 1) first attempts to communicate, the communication channel is randomly checked (carrier sense). It searches for an unused channel and, when a free channel is found, calls the other party (slave station 2) on the control channel. At this time, the free channel information is also transmitted to the other party. The side receiving the call moves to the channel designated by the other party and waits, after which communication is started.
After the end of communication, it automatically moves to the control channel and waits for the next call again.

Next, a line connection procedure in wireless data transmission will be described. For convenience of explanation, the slave station 2 is three ₍₂ 1 to 2 ₃₎ will be described the case (1: 3) for the,
The same applies to the case of 1 to N. FIG. 8 shows a transmission procedure in a normal case when there is no error. In FIG. 8, the master station 1 uses the control channel to connect the slave station 2 ₁ to 2 ₃ with a connection request signal (“required” in the figure). (Described) is transmitted, and each slave station 2 ₁ to 2 ₃ receives the connection request signal. Here, in the master station 1, a period timer for receiving a connection response signal (denoted as "accommodation" in the figure) which means an affirmative response from the slave stations 2 ₁ to 2 ₃ to the master station 1 side. To operate. The period of this timer is 400 mSEC for each slave station 2. Child station 2 ₁ to parent station 1
A connection response signal is returned to the master station 1, and the master station 1 receives the connection response signal (see FIGS. 8A and 8B). Then the connection response signal from the slave station 2 ₂ is returned to the master station 1 (FIG. 8
(C) refer), further the connection response signal from the slave station _{2 3} is returned reference (FIG. 8 (d)). As a result, the line is connected and data is transmitted from the master station 1 to each of the slave stations 2 ₁ to 2 ₃ .

[0004] First data to the master station 1 child station 2 ₁ is transmitted, and returns an acknowledge signal Ack to master station 1 after receiving the data in the child station 21 (see Figure 8 (b)). Then the master station 1 transmits the data to the slave station 2 _2, returns the acknowledge signal Ack to master station 1 after receiving the data in the child station 2 ₂ (see FIG. 8 (c)). Moreover the master station 1 transmits the data to the slave station 2 _3, acknowledge signal Ack to master station 1 after receiving the data in the child station 2 ₃
Is returned (see FIG. 8D).

[0005]

In the conventional transmission procedure, when an error occurs in transmitting or receiving the connection request signal and the connection response signal, the master station 1 retransmits the connection request signal. Significant time is required. That is, in FIG. 9 showing a case where an error occurs, the master station 1
When the slave station 2 ₁ and the slave station 2 ₃ receive the connection request signal normally when the slave station 2 2 transmits the connection request signal, and the slave station 2 ₂ cannot receive the connection request signal due to an error, FIG. as shown in), the connection response signal from the master station 1, the slave station 2 ₂ in time to receive a connection response signal from the slave station 2 ₂ can not receive. The connection response signals from the slave stations 2 ₁ and 2 ₃ are received by the master station 1 in each time zone.
When the master station 1 has the slave station 2 (here, the slave station 2 ₂ ) that cannot receive the connection response signal when the timer times out, the time for sending the data without sending the data to the slave station 2. After that, the connection request signal is retransmitted. After transmitting the connection response signal, the slave station 2 carries out carrier sensing, and returns to the control channel when the data is not transmitted even at the time when the data is transmitted, and the connection request signal from the master station 1 is sent. To stand by. Then, the connection request signal is retransmitted from the master station 1 and repeated until each of the slave stations 2 ₁ to 2 ₃ receives the connection request signal.

When an error occurs in this way, as shown in FIG. 9, the time when the master station 1 receives the connection response signals from the _three slave stations 2 ₁ to 2 _{3 is} 400, respectively.
In the case of mSEC, the time until the master station 1 retransmits the connection request signal is about 1.6 SEC, and there is a problem that the transmission efficiency is reduced. Note in the above example, although errors slave station 2 ₂ has been described as being generated, the other slave stations 2
_{The same} applies when an error occurs in ₁ , 2, or ₃ . Therefore, when there are many slave stations 2, the transmission efficiency becomes worse.

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object thereof is to provide a line connection device for data transmission capable of improving the transmission efficiency when an error occurs. Especially.

[0008]

Therefore, the line connection device for data transmission according to the present invention comprises one master station 1 and a plurality of slave stations 2.
Consists 21 _{to 3,} the main station 1 transmits a connection request signal to each slave station ₂ 1 to 2 _3, each slave station ₂ 1 to 2 ₃ that has received the connection request signal by predetermined rank 1 table of the slave station ₂ 1 to 2
₃ one by sending a connection response signal to the master station 1, after the master station 1 that has received the respective connection response signal from each slave station 2 ₁ to 2 _3, to transmit data to each slave station 2 ₁ to 2 ₃ In the data transmission system as described above, the master station 1 and each slave station 2 ₁ to 2 ₃
Timer 1 that counts in synchronization with each time division
Includes a 5, slave station ₂ 1 to 2 ₃ the master station from the time slot _t 2 ~t ₃ of the timer 15 transmits a connection response signal to the master station 1 1 and the child station ₂ 1 to 2 _3, respectively carrier If sensing is performed and the carrier cannot be detected, the master station ₁ shifts to the connection request signal resending state, and the slave stations 2 ₁ to 2 ₃ set the control means 11 that sets the connection request signal to the standby state to the master station 1 and the slave station. Station 2 ₁
It is characterized in that provided respectively to 2 _3.

[0009]

SUMMARY OF] According to line unit of the data transmission, the master station 1 if the error occurs in a certain slave station 2 _2, slave station 2 ₂ in which the error occurs at a predetermined timer time period t ₂ ~t ₃ This timer time period t
_Since there is no carrier between _{2 and} t ₃ , the master station 1
And the slave stations 2 ₁ , 2 ₃ have predetermined timer time zones t _{2 to} t _3.
Since there is no carrier, the timer time period t _{2 to} t
A connection response signal to a predetermined slave station 2 ₂ to be transmitted to the ₃ determines that an error has occurred. Then, the master station 1 shifts to the state of retransmitting the connection request signal, and the slave stations 2 ₂ and 2 ₃ shift to the standby state of the connection request signal from the master station 1. In this way, when the master station 1 and the slave stations 2 ₁ to 2 ₃ carry out carrier sensing and the connection response signal is not transmitted, it is immediately judged as an error, and the master station 1 retransmits the connection request signal. The time until the request signal is retransmitted is shortened, and the transmission efficiency can be improved. In particular, as the number of slave stations 2 is increased, the transmission efficiency when an error occurs can be greatly improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the data transmission line connection apparatus of the present invention will be described in detail with reference to the drawings. In the present invention, timers are used for both the master station 1 and the slave station 2, and the transmission and reception intervals are time-divided so as to synchronize with each station.

FIG. 6 shows a block diagram of the main part of the master station 1, which includes a transmitter 13 for transmitting a connection request signal and data from the antenna 16, and a reception for receiving a connection response signal and an acknowledge signal Ack from the slave station 2. A control unit 11 including a unit 14, a PLL synthesizer unit 12 that can switch the frequency (channel) of a carrier wave signal, and a microcomputer that controls transmission / reception in the PLL synthesizer unit 12 and frequency (channel) switching. , A timer 15 for time-divisionally controlling the interval between transmission and reception. Although FIG. 6 has been described as a block diagram of the main part of the master station 1, the slave station 2 is also functionally the same, and therefore the slave station 2 is also supported by using FIG. 6 as a functional block diagram.

Next, the operation of the present invention will be described. FIG. 3 shows a timing chart showing a control procedure in a normal case where no error occurs, and FIG. 4 shows a control flow chart of the master station 1.
Further, FIG. 5 shows a control flow chart of the slave station 2. First, the operation in the normal case will be described. In FIG. 4, when the master station 1 starts transmission to the slave station 2, the master station 1 searches for an empty channel and stores the empty channel if a free channel is found, as shown in step S1 (step S1).
2). Next, as shown in FIG. 3, from the master station 1 to each slave station 2 ₁
A connection request signal to _~ 2 transmits with empty channel information (step S3). Then, as shown in step S4, the master station 1 shifts to the selected data channel and starts the timer 15 (see FIG. 6) at time t ₁ shown in FIG. 3A (step S5). For convenience of explanation,
As in the conventional case, the number of child stations 2 is three. The time at which each of the slave stations 2 ₁ to 2 ₃ transmits a connection response signal to the master station 1 is, for example, 400 mSEC, and the slave stations 2 ₁ and 2
_2, may be set and priorities to the slave station 2 _3, is to synchronize the timer start and the time-out of timer 15 of the master station 1 and the child station 2.

[0013] As shown in FIG. 3 (b), and transmits a connection response signal between the slave station _{2 1} time _t 1 ~t ₂ to the master station 1, a connection response signal in the master station 1 in step S6 coming from the time out (step S8), and the reception standby of the connection response signal at time t ₂ again from slave station 2 ₂ starts a timer 15 when the. Then receiving a connection response signal from the slave station 2 ₂ within the timer time, further time t ₃
In and timer start, into the reception standby of the connection response signal from the slave station 2 _3. And after receiving the connection response signal from the slave station 2 _3, all the slave stations timeout 2 ₁ to 2 ₃
After step S9 is completed (step S9), the data transmission state is entered.

Next, control in the normal case on the slave station 2 side will be described with reference to FIG. When the connection request signal from the master station 1 is received in step S11, as shown in step S12, the process moves to the data channel designated by the master station 1,
The timer in the slave station 2 is synchronized with the master station 1 of the timer is started from the time t ₁ (step S13). Then, as shown in step S14, if the pre-set transmission time, each slave station 2 (slave station _{2 1} time _{t 1} ~ time _{t 2} shown in FIG. 3, slave station _{2 2} time _{t 2} ~ time t _3, and transmits a connection response signal to the master station 1 to the slave station _{2 3} times _{t 3} ~ time _{t 4)} (step S15). When the respective divided timer times out in the master station 1 (step S16), the master station 1 waits until the transmission time (timer time) of the connection response signal from another slave station 2 to the master station 1 ends, and then all the slaves When the timer time of the station 2 expires (step S20), each slave station 2 waits for reception of data from the master station 1.

[0015] After the line in this way are connected, as shown in FIG. 3, and transmits the data to the master station 1 child station 2 _1, slave station 2 ₁ an acknowledge signal Ack after receiving the data It is returned to the master station 1 (see FIGS. 3A and 3B).
Then the master station 1 transmits data to the slave station 2 _2, slave station 2 ₂ master station an acknowledge signal Ack after receiving the data 1
It is returned as shown in FIG. Moreover the master station 1 transmits data to the slave station 2 _3, the slave station 2 ₃ sends back, as shown in FIG. 3 (d) an acknowledge signal Ack to the master station 1 after receiving the data.

Next, when an error occurs, as shown in FIG.
This will be described with reference to FIGS. 4 and 5. As shown in Figure 1,
An error has occurred in the slave station 2 _2. In the master station 1, as shown in step S5 of FIG.
₁ (see FIG. 1), and in step S6 the slave station 2 ₁
It is determined whether or not the connection response signal from is received. Child station 2 ₁
In the side as shown in step S13 in FIG. 5, to start the slave station 2 ₁ timer in synchronization with the timer start of the master station 1 at time t _1. Then, in the slave station _{2 1} Step S
Since it is the transmission time of its own station at 14 (time t ₁ to time t _{2 in} FIG. 1), the connection response signal is transmitted to the master station 1 (step S15).

Since the slave station 2 ₂ has not received the connection request signal from the master station 1 due to an error as shown in FIG. 1, the slave station 2 ₂ transmits the connection response signal to the master station 1. Not done. So during the time to the connection response signal from the slave station _{2 2} In the master station 1 is returned (time _{t 2} ~ time _{t 3),} the slave station _{2 2}
4 is waiting for the connection response signal from the device, but since the connection response signal is not received in step S6 of FIG. 4 (because the carrier cannot be detected even if carrier sensing is performed), the process proceeds to step S7, and the timer time is exceeded. There If time-out occurs, the master station 1 returns to step S1 it is determined that an error has occurred in the slave station 2 _2. As a result, the master station 1 returns to the preset control channel and retransmits the connection request signal to each of the slave stations 2 ₁ to 2 ₃ again (see FIG. 1).

Since the slave station 2 in which the error has occurred does not receive the connection request signal from the master station 1 as shown in step S11 of FIG. 5, it does not move to step S12 and always returns to the master station. It is in the standby state for the connection request signal from the station 1.

[0019] Operation of the slave station 2 ₃ which has received the connection request signal from the master station 1 is as follows. That is, as shown in step S13 of FIG.
The timer of the slave station 2 ₃ is started in synchronization with 5.
And since the process proceeds to step S14 it is judged whether the transmission time of the own station, between times t _{1 ~} time t ₂ shown in FIG. 1 is a transmission time range of the slave station 2 _1, shown in FIG. 5 Step S
Go to 17. Here slave station 2 ₃ is subjected to carrier sense until itself transmits a connection response signal to the master station 1, the carrier when the slave station 2 ₁ is transmitting a connection response signal to the master station 1 Since it exists, the process proceeds to step S18,
When the time out at the time t ₂ proceeds to the step S20, because it is not yet finished the time of the connection response signal of all slave station 2 returns to the step S14. In step S14, the next time t _{2 ~} time t ₃ is the transmission time period of the slave station 2 _second connection response signal, step S17 is not a transmission time period of the connection response signal of the own station (slave station 2 ₃₎ Move to.
Since the connection response signal from the slave station 2 ₂ in which the error has occurred to the master station 1 is not transmitted, the carrier of the slave station 2 ₂ does not exist even if carrier sensing is performed in the slave station 2 ₃ . Therefore the process proceeds to step S19, and waits until time t _3, returns to the step S11 it is determined that the slave station 2 ₃ if the time-out errors slave station 2 ₂ occurs, a connection request from the base station 1 becomes the initial state Wait until the signal is retransmitted. In this embodiment, the case where an error occurs in the slave station 2 ₂ has been described, but the same applies to the case of the other slave stations 2 ₁ , 2 ₃ .

[0020] 0 Thus in the present invention, when an error occurs in the slave station 2 _2, the time to resend a connection request signal to the master station 1 child station 2, from the conventional 1.6 sec. It becomes 8 SEC, and it takes 1 to retransmit the connection request signal.
It only takes 2 hours. In this case, the case of three slave stations 2 has been described, but when the number of slave stations 2 further increases, the effect is further enhanced and the transmission efficiency can be improved. In the above embodiments, the communication medium is described as wireless such as electromagnetic waves, but the present invention can be applied to the case of wired communication.

FIG. 2 shows the transmission of data from the master station 1 to the slave station 2 and the slave station 2 as in the case of transmitting and receiving the connection request signal and the connection response signal between the master station 1 and the slave station 2. FIG. 6 is an explanatory diagram of a case where an acknowledge signal Ack is transmitted from the mobile station to the master station 1.
That is, after receiving the data from the master station 1, the slave station 2 transmits an acknowledge signal Ack to the master station 1 as soon as the time-out (time t ₁ point) by the timer is reached. The master station 1 receives the acknowledge signal A as soon as it times out (time t ₁ point).
The ck reception operation starts. Then a timeout (time t ₂
The next operation (data transmission to the next slave station 2,
(Acknowledge signal Ack is received from the slave station 2). Although FIG. 2 describes the transmission / reception of the data and the acknowledge signal Ack, the transmission / reception operation of the connection request signal and the connection response signal is the same as shown in parentheses, and the transmission / reception of the data and the acknowledge signal Ack is performed. When an error occurs during transmission / reception, the master station 1 cannot detect the carrier as described above, and therefore returns to the control channel and retransmits the connection request signal. Further, the error during the transmission of the data may be performed from the retransmission of the data.

[0022]

According to the data transmission line connection apparatus of the present invention, when an error occurs in a certain slave station, the slave station in which the error has occurred transmits a connection response signal to the master station within a predetermined timer period. Since there is no carrier in this timer time zone, the master station and the slave stations do not have a carrier in a predetermined timer time zone, and therefore a predetermined child station is required to transmit a connection response signal in that timer time zone. Judge that an error has occurred in the station. Then, the master station shifts to the state of retransmitting the connection request signal, and the slave station shifts to the standby state of the connection request signal from the master station. Therefore, the time until the connection request signal is retransmitted is shortened, and the transmission efficiency can be improved.
In particular, as the number of slave stations is increased, the transmission efficiency when an error occurs can be significantly improved.

[Brief description of drawings]

FIG. 1 is a timing chart showing a transmission procedure when an error occurs according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for transmitting / receiving data and an acknowledge signal between a master station and a slave station according to the embodiment of the present invention.

FIG. 3 is a timing chart showing a transmission procedure in a normal case according to the embodiment of the present invention.

FIG. 4 is a flowchart showing a control operation in the master station according to the embodiment of the present invention.

FIG. 5 is a flow chart showing a control operation in the slave station according to the embodiment of the present invention.

FIG. 6 is a functional block diagram of a main part of the master station according to the embodiment of the present invention.

FIG. 7 is a schematic system configuration diagram of wireless data transmission.

FIG. 8 is a timing chart showing a transmission procedure of a conventional example in a normal case.

FIG. 9 is a timing chart showing a transmission procedure when an error occurs in the conventional example.

[Explanation of symbols]

 1 master station 2 slave station 11 control unit (control means) 15 timer

Claims (1)

[Claims] 1. A master station (1) and a plurality of slave stations (2 ₁
〜2 ₃ ), and the master station (1) is each slave station (2 ₁ 〜 2 ₃ ).
Each of the slave stations (2 ₁ to 2 ₃ ) which has transmitted the connection request signal to the master station ( _{1 1} to 2 ₃ 2) in accordance with a predetermined order. To the slave station (2 ₁ to 2 ₃ ), the master station (1) receives the connection response signal from each slave station (2 ₁ to 2 ₃ ), and then transmits the connection response signal to each slave station (2 ₁ to
In the data transmission system 2 ₃₎ to transmit the data to be counted in synchronism with each time division to the master station (1) and each slave station (2 1 _{to 2 3)} Timer (15)
The provided, the slave station ₍₂ 1 to 2 ₃₎ the timer time zone (15) to transmit a connection response signal to the master station (1) from _(t 2 ~t ₃₎ to the master station (1) and child The stations (2 _{1 to} 2 ₃ ) each perform carrier sense, and when a carrier cannot be detected, the master station ( ₁ ) shifts to a connection request signal retransmission state, and the slave stations (2 ₁ to 2 ₃ ) connect to the connection request signal. The control means (11) for making the standby state of the master station (1) and the slave station (2 ₁ ~
2 ₃ ), respectively, a line connection device for data transmission, characterized in that