JPH0435233A - Radio packet alternate communication system - Google Patents

Abstract

PURPOSE:To improve the utilizing efficiency of an incoming line by allowing a control station to monitor a more data indicator in a data packet when a mobile equipment makes interactive communication with a data center via a control station and allowing the control station to make polling control only when the mobile equipment sends a data packet. CONSTITUTION:A control station 1 monitors plural mobile equipments 2-1 - 2-n sending a data packet alternately in interactive communication and more data indicator in a data packet from a data center 5. Then the control station applies polling control to the mobile equipments 2-1 - 2-n only when the mobile equipments 2-1 - 2-n have a token as the mobile equipments 2-1 - 2-n await a transmission data or are in the transmission standby state. Thus, the overhead due to idle polling control is reduced to improve the utilizing efficiency of the incoming line.

Description

[Detailed Description of the Invention] [Industrial Application Field] When a mobile device accesses and communicates with a data center via a control station, the present invention provides information on wireless communication between the control station and a plurality of mobile devices. The present invention relates to a wireless packet communication system that performs bidirectional simultaneous data transmission and reception. As such a mobile device, a mobile data terminal having a data terminal/output function can be considered. It can be widely used in wireless data communication systems in which data is transmitted and received between such mobile devices or between a mobile device and a certain data center via a control station.

[Prior Art] Conventionally, as a transmission control method that simultaneously transmits and receives data in both directions between a control station and multiple terminals using a common line,
A polling/selenoting method was considered.

FIG. 4 shows an example of a signal sequence of a conventional polling/serenoting type alternate monitoring type response system. In the same figure, the control station transmits a polling signal 51 to the mobile armor.After receiving an uplink data packet 52 from the mobile armor and transmitting a polling signal 51 from the control station to the mobile armor, the control station transmits a downlink data packet 53 to the mobile equipment B. After confirming that both have been completed, it first transmits a response request signal 54 to the mobile device B whose response transmission trigger is unknown, and after receiving a response 55 from the mobile device B, sends a response 56 of the uplink data packet to the mobile device A. It was sending.

[Problems to be Solved by the Invention] In the case of a communication system that combines conventional polling control and selecting control as described above, a control station sequentially sends one of all terminals regardless of whether the terminal has transmission data or not. After selecting and transmitting a polling signal to that terminal, it continues to transmit downlink selecting data packets to other terminals, but if the terminal that received the polling signal does not have any data to send and sends an empty signal, the empty signal length is often shorter than the length of the downlink data packet of the control station, so the uplink cannot be used until the transmission of the downlink data packet is completed, resulting in a significant drop in line usage efficiency.

In the case of one-way communication between mobile devices, the above drawback can be solved by agreeing in advance on the control line that the mobile devices will transmit, and then performing polling control only on the mobile devices that have data to be transmitted over the communication line. However, when a mobile device performs conversational communication,
Normally, the control station cannot identify the transmitting/receiving status of a mobile device, so the control station applies polling control to the mobile device even when the mobile device is receiving data or waiting to receive data. There was a problem in that communication efficiency decreased because signals were sent out.

An object of the present invention is to provide a wireless packet communication method that can solve the drawbacks of the prior art in simultaneous bidirectional data transmission and reception between a control station and a plurality of mobile devices, and can improve transmission delay time and line usage efficiency. The purpose is

[Means for Solving the Problems] According to the present invention, the above-mentioned problems are solved by the means described in the claims.

That is, in the present invention, when a mobile device accesses a data center, etc. accommodated by a fixed network via a control station and performs conversational communication, the control station performs conversational communication between the mobile device and the center using data packets/). This is a wireless packet alternating communication system that monitors using a more data indicator and controls polling of a mobile device only while the mobile device has the right to transmit.

[Function] The present invention enables a control station to transmit multiple data packets alternately in conversational communication by using a more data indicator in a data packet from a mobile device and a data center (with a continuation packet in M-1 and a transmission time in MO). display the end).
By performing polling control on the mobile device only while the mobile device has the right to transmit, such as when the mobile device has data to transmit or is in a waiting state for transmission, overhead due to missed polling control is reduced and uplink usage efficiency is improved. It is intended to improve

[Embodiment] Fig. 1 is a diagram showing an example of a system configuration for implementing the present invention, in which 1 is a control station, 2-1 to 2n are N mobile devices (data terminals), and 3a is a system from the control station. 3b is a common downlink radio communication line from the control station to the mobile device, 4a is the common uplink radio control line from the mobile device to the control station, and 4b is the common downlink radio control line from the mobile device to the control station. A common upstream wireless communication line 5 represents a data center connected to the control station directly or via a dedicated line or fixed packet network 6.

FIG. 2 is a diagram showing a signal sequence between a control station and a mobile device when one mobile device makes a call, connects to a data center, and then performs conversational communication.

Figure 3 shows the signal sequence when the control station receives a data packet from the mobile armor while simultaneously transmitting a data packet to another mobile equipment following a polling signal requesting data transmission from the mobile equipment that has data to be transmitted. FIG.

The operation of the embodiment will be described below with reference to the above figures.

First, in FIG. 1, a case will be described in which mobile devices 2-1 to 2-n access data center 5 via a control station and perform conversational communication. In the figure, wired packet terminal interfaces (X,
It is also called the X.25 protocol and consists of a layer 2 frame level and a layer 3 packet level. ) are connected. In addition, the wireless section between the control station 1 and the mobile device uses wireless-specific protocols such as polling/selenoting control procedures for multi-point connections in layer 2, and a 25-packet level protocol with a short maximum data packet length in layer 3. ,
The control station performs these protocol exchanges.

A mobile device wishing to perform conversational communication with the data center 5 of the fixed packet network 6 first makes a call using the radio control line between the mobile device and the control station 1. The subsequent call connection in the wireless section is performed in the same way as in the conventional car phone system, and once the connection with the center on the fixed network side is completed, one of the wireless communication lines is assigned for subsequent data transmission and reception (as in the case of the conventional call connection described above). Call connection is described in detail in the document ``Supervised by Moriji Kuwahara [Car Telephone] Coronasha P, 191-197'')
. In reality, multiple mobile devices are assigned to one wireless communication line, and data packets are received from a certain mobile device and data packets are sent to the ground station at the same time under polling/serenoting control by the control station. First, in FIG. 2, conversation communication between a control station and one mobile device will be explained as an example.

When the call connection is completed and one communication line is assigned,
As shown in FIG. 2, the control station first determines that the mobile device that made the call has the transmission data (transmission right), and then assigns a terminal address (this address may be temporarily assigned) to this mobile device. ), and when the mobile device with the corresponding address receives this signal, it transmits the data packet 8, and repeats this operation until the end of data transmission (if the mobile device's transmission data length is If the data packet is larger than the maximum length, it is divided into multiple data packets and the final data packet is sent with less than the maximum length). The control station uses the more data indicator (M) in the data packet from the mobile device to the center.
- By monitoring 〇, it knows the end of transmission and temporarily stops polling control.

Thereafter, when a data packet is sent from the data center to this mobile device, the control station determines that the center side has the right to transmit, and transmits this to the mobile device as centering data 9 with a terminal address. When the mobile device receives a data packet, it transmits a response signal and repeats this operation until the data reception is completed. In the same way as above, the control station learns from the more data indicator G in the data packet that the center's data transmission has ended, temporarily suspends centering control, and then determines that the right to transmit has been transferred to the mobile device, so it sends a message to the mobile device. Polling control is restarted, and the above polling control and centering control are repeated until the end of communication.

As explained in the above example, if the maximum data packet length is different between the wired section and the wireless section (communication quality is poor in the wireless section, it is generally necessary to shorten the packet length), The control station needs to perform packet length conversion including control of the more data indicator.

FIG. 3 shows a control sequence when the control station simultaneously receives data packets from mobile equipment A through polling control and transmits data packets to mobile equipment A through centering control.

In this case, the control station transmits a data packet to the mobile device B following the polling signal to the mobile device B that has the data to be transmitted. The mobile armor that receives the polling signal also transmits data packets, but the transmission of both data packets begins almost simultaneously.

[Effects of the Invention] As explained above, according to the present invention, in simultaneous data transmission/reception by polling/serenoting control between one control station and a plurality of mobile units a, the mobile unit passes through the control station and reaches the data center. When performing conversational communication with a mobile device, the control station monitors the more data indicator in the data packet and performs polling control only while the mobile device is transmitting the data packet. This has the advantage of improving usage efficiency and significantly reducing delay time.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a system configuration for implementing the present invention;
FIG. 2 is a diagram showing an example of a signal sequence between a control station and a mobile device, FIG. 3 is a diagram showing another example of a signal sequence between a control station and a mobile device, and FIG. 4 is a diagram showing an example of a signal sequence between a control station and a mobile device. FIG. 3 is a diagram illustrating an example of a signal sequence of an alternate monitoring type response method using a polling/sensing method. 1... Control station, 2-1 to 2-n... Mobile device, 3a... Downlink radio control line, 3b...
...downlink radio communication line, 4a...-uplink radio control line, 4b...uplink radio communication line, 5...
...Data center, 6...Fixed packet network,
7...Polling signal, 8.9...Data packet

Claims (1)

[Scope of Claims] At least one pair of communication lines is provided between one control station and the plurality of mobile devices, with one pair being an uplink from the mobile device to the control station and a downlink from the control station to the mobile devices. After setting up multiple pairs of wireless lines consisting of a control line and agreeing that the control station will perform data communication with the mobile device on the control line,
On the communication line, the control station is configured to simultaneously transmit and receive data in both directions by receiving upstream data packets from one mobile station using polling control and simultaneously transmitting downlink data packets to the other mobile station using fast select control. In a wireless packet communication system, when a mobile device accesses a data center, etc. that accommodates a fixed network via a control station and performs conversational communication, the control station performs conversational communication between the mobile device and the center by converting data packets into data packets. 1. A wireless packet alternating communication system characterized by polling a mobile device only while the mobile device has transmission rights as monitored by a data indicator.