JP2914722B2 - Wireless packet alternate communication method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a case where a mobile station accesses a data center via a control station and performs communication, on a wireless line between the control station and a plurality of mobile stations. The present invention relates to a wireless packet communication system for performing bidirectional simultaneous data transmission and reception. As such a mobile device, a mobile data terminal having a data input / output function can be considered. The present invention can be widely used for a wireless data communication system for transmitting and receiving data between such mobile devices or between a mobile device and a certain data center via a control station.

[Prior Art] Conventionally, a polling / selecting method has been considered as a transmission control method for performing simultaneous data transmission and reception in both directions between a control station and a plurality of terminals using a common line.

FIG. 4 shows an example of a signal sequence of an alternate monitoring type response system in a conventional polling / selecting system. In the figure, after transmitting a polling signal 51 to the mobile armor, the control station receives an uplink data packet 52 from the mobile armor and transmits a polling signal 51 from the control station to the mobile armor, and then transmits a downlink data packet 53 to the mobile equipment B 53 After confirming that both have been completed, first, a response request signal 54 is transmitted to the mobile unit B whose response transmission trigger is unknown, and a response 55 from the mobile unit B
Response to the mobile armor after receiving
Was sent.

[Problem to be Solved by the Invention] In the case of the communication system in which the conventional polling control and the selecting control are combined as described above, the control station sequentially transmits one of all terminals regardless of whether or not the terminal has transmission data. After selecting and sending a polling signal to that terminal,
Subsequently, the downlink selecting data packet is transmitted to another terminal, but when the terminal receiving the polling signal transmits an empty signal without transmitting data, the empty signal length is shorter than the downlink data packet length of the control station. Therefore, there is a disadvantage that the uplink cannot be used until the transmission of the downlink data packet is completed, and the line use efficiency is significantly reduced.

The above disadvantage can be solved by performing polling control only on the mobile station having transmission data on the communication line after agreeing the transmission of the mobile station on the control line in advance when the mobile station is in one-way communication. However, when a mobile station performs conversational communication, the control station cannot usually identify the transmission / reception state of the mobile station. Therefore, even when the mobile station is receiving data or is in a reception standby state, the control station transmits to the mobile station. On the other hand, the polling control is performed, and as a result, an empty signal is transmitted, so that there is a problem that the communication efficiency is reduced.

An object of the present invention is to provide a wireless packet communication method capable of solving the drawbacks of the prior art in simultaneous bidirectional data transmission and reception between a control station and a plurality of mobile stations and improving transmission delay time and line use 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, the present invention provides at least one pair of communication lines between one control station and a plurality of mobile stations, with one pair of the uplink from the mobile station to the control station and the downlink from the control station to the mobile station. After providing a plurality of pairs of wireless lines comprising a control line, the control station on the control line agrees to perform data communication with the mobile station on the communication line, and then the control station on the communication line performs polling control on one side. In a wireless packet communication system configured to perform simultaneous two-way data transmission and reception by transmitting a downlink data packet to another mobile station by fast select control at the same time as receiving an uplink data packet from the mobile station, When a conversation is performed by accessing a data center or the like that accommodates a fixed network via a network, the control station transmits a data packet of the conversational communication between the mobile device and the center. The mobile station starts transmitting data packets to the control station after the control station starts polling, and a more data indicator indicating whether or not there is a continuation packet of the data packet or a subsequent data packet. Indicates that there is no continuation packet, and until the transfer of the data packet is completed and the response from the control station to this is completed,
After the mobile station determines that the mobile station has the transmission right, or after the mobile station responds to the response request from the control station, the mobile station transmits data to the control station in response to the polling of the control station. The transmission of the packet is started, the more data indicator indicating the presence or absence of a continuation packet of the data packet or the subsequent data packet indicates that there is no continuation packet, the transfer of the data packet is completed, and the control station responds to this. Until the response is completed, the mobile station determines that the mobile station has the transmission right, and polls the mobile station only while determining that the mobile station has the transmission right. It is.

[Operation] The present invention relates to a mobile station and a more data indicator in a data packet from a data center in which a control station alternately transmits a plurality of data packets by conversation communication (a continuous packet exists when M = 1 and a temporary transmission when M = 0). The end of the polling control is monitored, and polling control is performed for the mobile station only while the mobile station has the transmission right, such as when the mobile station has transmission data or is in a transmission waiting state. To reduce the overhead due to the above and improve the efficiency of use of the uplink.

Embodiment FIG. 1 is a diagram showing an example of a system configuration for implementing the present invention, wherein 1 is a control station, 2-1 to 2-n are N mobile terminals (data terminals), and 3a is a control station. Common downlink radio control line from station to mobile station, 3b common downlink radio communication line from control station to mobile station, 4a common uplink radio control line from mobile station to control station, 4b from mobile station Reference numeral 5 denotes a common upstream radio communication line to the control station, and 5 denotes a data center connected directly to the control station or via a dedicated line or a fixed packet network 6.

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

FIG. 3 shows a signal sequence in the case where the control station transmits a data packet to another mobile equipment B, and simultaneously receives a data packet from the mobile equipment, following a polling signal requesting data transmission to the mobile equipment having transmission data. FIG.

 Hereinafter, the operation of the embodiment will be described with reference to the above drawings.

First, in FIG. 1, a case will be described in which the mobile units 2-1 to 2-n access the data center 5 via the control station and perform conversational communication. In the figure, a wired packet terminal interface (X.25) is connected between the control station 1 and the fixed packet network 6 and between the data center 5 and the fixed packet network 6.
It is also called a protocol and consists of a layer 2 frame level and a layer 3 packet level. ). The radio section between the control station 1 and the mobile station is radio-specific. For example, layer 2 uses a polling / selecting control procedure for multipoint connection, layer 3 uses an X.25 packet level protocol having a short maximum data packet length, The control station performs these protocol exchanges.

A mobile station that wants to perform conversational communication with the data center 5 of the fixed packet network 6 first makes a call using a wireless control line between the mobile station and the control station 1. Subsequent call connection in the wireless section is performed in the same manner as in the conventional car telephone system, and when the connection with the center is completed on the fixed network side, one of the wireless communication lines is allocated to subsequent data transmission / reception (the above-described conventional call connection). The call connection is described in detail in, for example, the document "Supervised by Moriji Kuwahara [Car Phone] Corona Co., Ltd., pp. 191-197). In addition,
In practice, a plurality of mobile units are allocated to one wireless communication line, and data packet reception from one mobile unit and data packet transmission to another mobile unit are performed simultaneously by polling / selecting control of a control station. First, a conversation communication between the control station and one mobile station will be described with reference to FIG.

When the call connection is completed and one communication line is allocated, the control station determines that the calling mobile station has transmission data (transmission right) first as shown in FIG. A polling signal 7 with a sequence number which is expected as a terminal address (this address may be temporarily assigned) is transmitted. When this signal is received by a mobile station having the corresponding address, a data packet 8 is transmitted, This operation is repeated until the transmission is completed (if the transmission data length of the mobile station is larger than the maximum length of the data packet, the mobile station is divided into a plurality of data packets and the final data packet is transmitted with a length less than the maximum length). The control station is a more data indicator (M) in the data packet from the mobile station to the center.
By monitoring = 0, the transmission end is recognized and the polling control is suspended.

Thereafter, when a data packet is sent from the data center to this mobile station, the control station determines that the center has the transmission right, and determines this as the selecting data 9 with the terminal address.
To the mobile device. Upon receiving the data packet, the mobile station transmits a response signal and repeats this operation until the data reception is completed. The control station knows the end of data transmission of the center by the more data indicator = 0 in the data packet in the same manner as described above, suspends the selecting control, and then judges that the transmission right has been transferred to the mobile station, and The polling control is restarted, and thereafter, the polling control and the selecting control are repeated until the communication ends.

As described in the above example, when the maximum data packet length is different between the wired section and the wireless section (the wireless section has poor communication quality, so 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 in the case where the control station simultaneously receives a data packet from the mobile equipment by polling control and transmits a data packet to mobile equipment B by selecting control. In this case, the control station transmits a data packet to the mobile unit B following the polling signal to the mobile unit having the transmission data. The mobile armor that has received the polling signal also transmits data packets, but transmission of both data packets is started almost simultaneously.

[Effects of the Invention] As described above, according to the present invention, in simultaneous data transmission / reception by polling / selecting control between one control station and a plurality of mobile stations, the mobile station transmits data to the data center via the control station. When performing conversational communication with the control station, the control station monitors the more data indicator in the data packet and performs polling control only while the mobile station is transmitting the data packet. There is an advantage that the use efficiency can be improved and the delay time can be significantly reduced.

[Brief description of the 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 the control station and the mobile device, FIG. 3 is a diagram showing another example of a signal sequence between the control station and the mobile device, and FIG. It is a figure which shows the example of the signal sequence of the response system of the alternating monitoring type in a polling / selecting system. 1 ... Control station, 2-1 to 2-n ... Mobile device, 3a ... Downlink wireless control line, 3b ... Downlink wireless communication line, 4a ... Uplink wireless control line, 4b ... Uplink wireless communication line 5 ... data center, 6 ... fixed packet network, 7 ... polling signal,
8,9 …… Data packet

Continuation of Front Page (72) Inventor Yoshiaki Shikata 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-B-60-17188 (JP, B2) US Patent 4,446,001 (US, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H04B 7/24-7/26 H04L 11/00 310 H04Q 7/00-7/38

Claims (1)

(57) [Claims] At least one pair of communication lines is controlled between one control station and a plurality of mobile stations, with one pair of an uplink line from the mobile station to the control station and a downlink line from the control station to the mobile station. A plurality of pairs of wireless lines are provided, and after the control station agrees to perform data communication with the mobile station on the communication line on the control line, the control station on the communication line performs polling control on one of the mobile lines. In a wireless packet communication system configured to perform simultaneous two-way data transmission and reception by transmitting a downlink data packet to another mobile station by fast select control at the same time as receiving an uplink data packet from the mobile station, The control station monitors the data packet of the conversational communication between the mobile unit and the center when accessing the fixed data accommodating data center via the After the control station starts polling, the mobile station starts transmitting a data packet to the control station, and the more data indicator indicating the presence or absence of a continuation packet of the data packet or a subsequent data packet is a continuation packet. Until the transfer of the data packet is completed and the response from the control station is completed, it is determined that the mobile station has the transmission right, or a response request is received from the control station. Is received from the mobile station, the mobile station starts transmitting data packets to the control station in response to polling by the control station, and determines whether there is a continuation packet of the data packet or a subsequent data packet. Indicates that there is no continuation packet, and the transfer of the data packet has been completed. Until the response from the control station is completed, the mobile station determines that the mobile station has the transmission right, and polls the mobile station only while determining that the mobile station has the transmission right. Wireless packet alternate communication method.