JP2871643B2 - Wireless data communication terminal system and its child device, master device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless data communication terminal system, and more particularly to a synchronous PPP (Point t) that flows through a communication network such as the Internet via an ISDN line.
o Point Protocol) and a wireless data communication terminal system for transmitting the frame using a wireless line, and a slave unit and a master unit thereof.

[0002]

2. Description of the Related Art A WAN (WLAN) such as an ISDN line is usually used.
LAN (L) via ide Area Network
For example, a Point to Point Protocol is used to connect to the Internet. Conventionally, in a wireless data communication terminal system using this type of protocol, when data transmission is performed in a wireless section between the slave unit and the master unit, an asynchronous signal is directly transmitted from the slave unit to the master unit. Using and transmitting.

[0003]

In the conventional system described above, when the PPP frame is transmitted asynchronously in the radio section, the overhead required for the asynchronous transmission is reduced by about 1/0 compared to the case where the PPP frame is transmitted synchronously. .8 times as much.

[0004] The reason for this 1.25-fold increase is as follows.
Usually, the minimum unit for sending this kind of data is 8 bits. When transmitting this 8-bit data, additional bits of a start bit and a stop bit are required. That is, when transmitting 8-bit data, it is necessary to transmit the data in a 10-bit configuration, and a margin for 2 bits is required.

On the other hand, at the time of synchronous transmission, redundant bits required for transmitting 8-bit data are less than 1 bit. This is because, during synchronous transmission, 8 bits are usually sent in a 1.5k frame, and the redundant bits required for the 1.5k frame are at least 14 bits. That is, at the time of synchronous transmission, (valid data 8 × 1500) / (valid data 8 × 1500 + redundant 14 bits) is almost 1, indicating that there is almost no redundancy.

Therefore, in the case of the above-mentioned system, there is a problem that if transmission is performed asynchronously, a line with limited resources cannot be used effectively.

An object of the present invention is to provide a wireless data communication terminal system that handles a synchronous PPP frame and an asynchronous PPP frame. By transmitting a synchronous PPP frame even in a wireless section, a line can be used effectively and transmission efficiency is improved. It is an object of the present invention to provide a wireless data communication terminal system capable of performing the above-mentioned operations, and a slave unit and a master unit.

[0008]

According to the present invention, there is provided a wireless data communication terminal system comprising: an asynchronous character section for transmitting / receiving an asynchronous PPP frame;
A character conversion unit that performs mutual conversion with a P frame and calculates a data length when an asynchronous PPP frame is converted into a synchronous PPP frame, and a wireless communication device of a predetermined length that is constantly transmitted on a wireless line. After the information of the data length is described in the frame, the timing for transmitting the radio frame is output, and when the data is received from the character conversion unit, the data is put on the radio frame and transmitted. And a radio frame generation / reconstruction unit for transmitting data in the received frame to the character conversion unit, and receiving the timing and transmitting data from the character conversion unit to the radio frame generation / reconstruction unit according to the timing. A slave unit including a wireless synchronization unit; and the wireless frame generator. It monitors whether there is any significant data in the radio frame transmitted from the restoration unit, outputs the timing of transmitting the radio frame when transmitting data to the radio frame generation / restoration unit, and outputs the data of the synchronous PPP frame via the radio line. And a wireless frame part for transmitting
A network controller for interfacing with a network, and when a synchronous PPP frame generated by the radio frame unit is received, the synchronous PPP frame is temporarily stored for speed matching with an ISDN line, and a synchronous PPP frame is received from the network controller. And a synchronization unit for temporarily storing the data and calculating the data length, and a synchronization unit for receiving the timing and transmitting the data of the synchronous PPP frame from the synchronization conversion unit to the radio frame unit according to the timing. And a master unit composed of Each of the radio frame generation / restoration unit and the radio frame unit has a unit for dividing a radio frame length by a transmission speed of a radio line in order to obtain a transmission timing value of a radio frame. The asynchronous character part for transmitting and receiving the asynchronous PPP frame and the asynchronous PPP frame and the synchronous PPP frame
When a PP frame is converted into a synchronous PPP frame, a character conversion unit for calculating the data length, and the information on the data length in a wireless frame of a predetermined length that is constantly transmitted on a wireless line. After the description, a timing for transmitting a wireless frame is output, and when data is received from the character conversion unit, data is added to the wireless frame and transmitted. When a wireless frame is received from the other party, the data in the received frame is transmitted. And a radio synchronization unit that receives the timing and transmits data from the character conversion unit to the radio frame generation / restoration unit according to the timing.

Further, the master unit of the present invention, after describing the data length information in a radio frame of a predetermined length which is always transmitted on a radio line, determines the timing for transmitting the radio frame. When receiving and outputting data from the character conversion unit, the data is put on a wireless frame and transmitted. On the contrary, when a wireless frame is received from the other party, a wireless frame generation for transmitting data in the received frame to the character conversion unit is performed. It monitors whether there is significant data in the radio frame transmitted from the restoration unit, outputs the timing of transmission of the radio frame when transmitting data to the radio frame generation / restoration unit, and transmits the data of the synchronous PPP frame via the radio line. A wireless frame unit for transmitting the packet through the network, a network control unit for interfacing with an ISDN network, and the wireless frame unit. When the synchronous PPP frame generated by the network section is received, it is temporarily stored for speed matching with the ISDN line, and when the synchronous PPP frame is received from the network control section, it is temporarily stored and the data length is reduced. It comprises a synchronization conversion unit for calculating, and a synchronization unit for receiving the timing and transmitting the data of the synchronous PPP frame from the synchronization conversion unit to the radio frame unit according to the timing.

According to the present invention, in the slave unit, the asynchronous PPP frame is converted into a synchronous PPP frame and transmitted over the radio line to the master unit, and after adjusting the timing, the master unit adjusts the timing to the ISDN line. By transmitting, the line can be used effectively and the transmission efficiency can be improved.

[0011]

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

FIG. 1 is a diagram for explaining a wireless data communication terminal system according to the present invention. FIG. 2 (a) is a block diagram of a slave unit in FIG. 1, and FIG. 2 (b) is a master unit in FIG. It is a block diagram of a machine.

The present system comprises a personal computer (hereinafter referred to as a PC) 1 having communication software for inputting and outputting data and a slave unit 2 connected by an RS232C line 4.
And a base unit 3 connected to the slave unit 2 via a wireless line 5 and interfacing with an ISDN line 6. For example, the slave unit corresponds to a slave terminal in a PHS (Personal Handy Phone System), and the master unit corresponds to home equipment for connecting the terminal to a public line.

The slave unit 2 performs the mutual conversion between the asynchronous PPP frame and the synchronous PPP frame, and converts the asynchronous PPP frame into the synchronous PPP frame. A character conversion unit 22 that calculates
After describing the data length information in a radio frame of a predetermined length that is constantly transmitted on the radio line, the timing for transmitting the radio frame is output, and when the data is received from the character conversion unit 22, the radio frame is output. When a wireless frame is received from a partner, a wireless frame generation / restoration unit 23 that transmits data in the received frame to the character conversion unit 22 is transmitted. And a wireless synchronization unit 24 for receiving and transmitting data from the character conversion unit 22 to the wireless frame generation / restoration unit 23 according to this timing.

The base unit 3 monitors whether or not there is significant data in the radio frame transmitted from the radio frame generation / restoration unit 23, and adjusts the transmission timing of the radio frame when transmitting data to the radio frame generation / restoration unit 23. Output and synchronization P
A wireless frame unit 31 for transmitting data of the PP frame via a wireless line, a network control unit 32 for interfacing with an ISDN network, and, when a synchronous PPP frame generated by the wireless frame unit 31 is received, this is sent to the ISDN line. When the synchronous PPP frame is received from the network control unit 32, the synchronous conversion unit 33 temporarily stores the synchronous PPP frame and calculates the data length.
And a synchronizing unit 34 for receiving a timing for transmitting a radio frame and transmitting the data of the synchronous PPP frame from the synchronization conversion unit 33 to the radio frame unit 31 according to the timing.

Referring to FIG. 1, when data is transmitted from the PC 1 to the ISDN line 6, the handset 2 connected to the PC 1 transmits and receives an asynchronous PPP frame to and from the PC 1. The slave unit 2 that has received the asynchronous PPP frame generates a synchronous PPP frame therein, transmits the synchronous PPP frame on a wireless frame of a wireless line 5 that constantly transmits a frame of a predetermined length, and transmits the frame. The effective data length can be described in this radio frame. Base unit 3 having received the radio frame extracts a synchronous PPP frame as significant data from the radio frame,
Transmit to line 6.

On the other hand, the synchronous PPP frame from the ISDN line 6 is put on a radio frame by the master unit 3 and transmitted to the slave unit 2. Handset 2 extracts a synchronous PPP frame as significant data from the radio frame and
After being converted to a PP frame, it is transmitted to PC1.

With reference to FIG.
The operation at the time of transmitting data to the line 6 will be described. PC1
The asynchronous character unit 21 that has received the asynchronous PPP frame from the controller transmits the received data to the character conversion unit 22. The character conversion unit 22 converts an asynchronous PPP frame into a synchronous PPP frame. The conversion between the asynchronous PPP frame and the synchronous PPP frame is performed according to the well-known RFC Recommendation 1171, APENDIX A, and RFC Recommendation 1548.
It should be done according to.

When the conversion is completed, the character conversion unit 22 calculates the data length. The reason for calculating the data length is that an asynchronous PPP frame flowing through the RS232C line 4 or a synchronous PPP frame flowing through the ISDN line 6 are transmitted irregularly. On the other hand, the synchronous PPP frame is transmitted at a constant length through the radio line 5 at a constant length, so that the synchronous PPP frame on the radio frame is transmitted irregularly. This indicates that there may be cases where valid data exists and cases where valid data does not exist. Therefore, when a synchronous PPP frame is placed on a radio frame, it is necessary to notify valid data, that is, the length of the synchronous PPP frame. After notifying the valid data length, the radio frame generation / restoration unit 23 notifies the radio synchronization unit 24 of the timing of transmitting the radio frame after describing the valid data length in the radio frame.

The reason for notifying the wireless frame transmission timing is that the wireless frame has a fixed-length frame configuration. In the case of a fixed-length frame, the frame transmission timing is determined by time. That is, as the transmission timing, a value obtained by dividing the wireless frame length by the transmission rate of the wireless section is the wireless frame transmission interval. Therefore, the right to determine the data transmission timing is not in the character conversion unit 22 but in the radio frame generation / restoration unit 2.
3 will be decided.

The radio synchronization unit 24 causes the character conversion unit 22 to transmit data in accordance with the timing notified from the radio frame generation / restoration unit 23. Character converter 2
The wireless frame generation / restoration unit 23 that has received the data constituting the synchronous PPP frame from No. 2 transmits the data to the base unit 3 by putting the data on the wireless frame.

Base unit 3 that has received a radio frame from handset 2
Wireless frame unit 31 constantly monitors whether there is significant data in the wireless frame. The simplest method of determining the presence or absence of significant data can be realized by monitoring whether the data length is 0. In the case of a wireless frame having a frame number, the data of the last normally received wireless frame can be used. This can be realized by monitoring whether the length is 0 or not.

The synchronization converter 33 normally sends a synchronization flag defined by APENDIX A of RFC Recommendation 1171 to the network controller 32. When the data is received by the wireless frame unit 31, the data is transmitted to the synchronization conversion unit 33. The synchronization conversion unit 33 temporarily stores the synchronization PPP frame generated by the wireless frame unit 31. The reason is that since the speeds of the ISDN line 6 and the wireless line 5 are different, it is necessary to perform speed matching between them. The synchronization conversion unit 33 transmits the temporarily stored PPP frame to the ISDN line 6 via the network control unit 32. When significant data, that is, a synchronous PPP frame does not come in the radio frame, a flag is generated in the synchronous conversion unit 33 and the network control unit 32
Transmitted via.

Next, the operation when data is transmitted from the ISDN line 6 to the PC 1 will be described. The network control unit 32 that has received the synchronous PPP frame from the ISDN line 6 transmits the received data to the synchronous conversion unit 33. Synchronous conversion unit 33
Temporarily stores the synchronous PPP frame, calculates the data length, and notifies the synchronizing unit 34 of the data length. The wireless frame unit 31 notifies the synchronization unit 34 of the timing of wireless frame transmission,
In response to an instruction from the synchronization unit 34 to the synchronization conversion unit 33, the synchronization PPP
The frame data is transmitted as a wireless frame. Since this processing operation is the same as that of the slave unit when transmitting from the PC 1 to the ISDN line 6, the description is omitted.

The wireless frame generation / restoration unit 23 of the slave 1 that has received the wireless frame transmits the data in the received wireless frame to the character conversion unit 22. The character conversion unit 22 converts the received frame, that is, the synchronous PPP frame into an asynchronous PPP frame, and transmits this to the PC 1 via the asynchronous character unit 21.

[0026]

As described above, according to the present invention, in a wireless data communication terminal system that handles a synchronous PPP frame and an asynchronous PPP frame, a synchronous PPP frame is also used in a wireless section between a slave unit and a master unit. 1. By transmitting data, 1. compared with the case of transmitting data asynchronously,
This makes it possible to increase the transmission efficiency by 25 times, thereby making it possible to use the wireless line effectively and to improve the transmission efficiency.

[Brief description of the drawings]

FIG. 1 is a diagram for describing an embodiment of the present invention.

FIG. 2A is a block diagram showing an embodiment of a slave unit of the present invention, and FIG. 2B is a block diagram showing an embodiment of a master unit of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PC 2 slave unit 3 base unit 21 asynchronous character unit 22 character conversion unit 23 wireless frame generation / restoration unit 24 wireless synchronization unit 31 wireless frame unit 32 network control unit 33 synchronization conversion unit 34 synchronization unit

Claims (4)

(57) [Claims] 1. An asynchronous character part for transmitting and receiving an asynchronous PPP frame, an asynchronous PPP frame and a synchronous PPP
A character converter for calculating the data length when an asynchronous PPP frame is converted into a synchronous PPP frame while performing mutual conversion with the frame, and a radio frame of a predetermined length constantly transmitted on a radio line After the information of the data length is described therein, the timing for transmitting the radio frame is output, and when the data is received from the character conversion unit, the data is put on the radio frame and transmitted, and conversely, the radio frame from the other party is received. Sometimes, a radio frame generation / restoration unit that transmits data in the received frame to the character conversion unit, and a radio that receives the timing and transmits data from the character conversion unit to the radio frame generation / restoration unit according to the timing. A slave unit including a synchronization unit; and the wireless frame generation. It monitors whether there is any significant data in the wireless frame transmitted from the original unit, outputs the wireless frame transmission timing at the time of data transmission to the wireless frame generation / restoration unit, and outputs the synchronous PPP frame data via the wireless line. A wireless frame unit for interfacing with an ISDN network; and a synchronous PPP frame generated by the wireless frame unit, when received, temporarily stores the received synchronous PPP frame for speed matching with an ISDN line. When a synchronous PPP frame is received from the network control unit, the synchronous PPP unit temporarily stores the synchronous PPP frame and calculates a data length. The synchronous PPP unit receives the timing, and transmits the synchronous PPP frame to the radio frame unit according to the timing. And a synchronization unit for transmitting frame data. Wireless data communication terminal system to be. 2. The wireless frame generating and restoring unit and the wireless frame unit each have means for dividing a wireless frame length by a transmission rate of a wireless line in order to obtain a transmission timing value of a wireless frame. 2. The wireless data communication terminal system according to 1. 3. An asynchronous character part for transmitting and receiving an asynchronous PPP frame, an asynchronous PPP frame and a synchronous PPP
A character converter for calculating the data length when an asynchronous PPP frame is converted into a synchronous PPP frame while performing mutual conversion with the frame, and a radio frame of a predetermined length constantly transmitted on a radio line After the information of the data length is described therein, the timing for transmitting the radio frame is output, and when the data is received from the character conversion unit, the data is put on the radio frame and transmitted, and conversely, the radio frame from the other party is received. Sometimes, a radio frame generation / restoration unit that transmits data in the received frame to the character conversion unit, and a radio that receives the timing and transmits data from the character conversion unit to the radio frame generation / restoration unit according to the timing. A slave unit comprising a synchronization unit. 4. A timing for sending a radio frame is described after describing the data length information in a radio frame of a predetermined length which is always transmitted on a radio line, and the character conversion unit outputs the timing. When the data is received, the data is put on the radio frame and transmitted. On the contrary, when the radio frame is received from the other party, the radio transmitted from the radio frame generation / restoration unit that transmits the data in the received frame to the character conversion unit. A wireless frame unit for monitoring whether there is significant data in the frame, outputting a wireless frame transmission timing when transmitting data to the wireless frame generation / restoration unit, and transmitting synchronous PPP frame data via a wireless line; A network control unit for interfacing with the ISDN network, and a synchronization P generated by the radio frame unit. When a P frame is received, it is temporarily stored for speed matching with the ISDN line, and when a synchronous PPP frame is received from the network control unit, it is temporarily stored and a synchronization conversion unit for calculating a data length is provided. A synchronization unit for receiving the timing and transmitting the data of the synchronous PPP frame from the synchronization conversion unit to the radio frame unit according to the timing.