JPH02237328A - Radio transmission system - Google Patents

Abstract

PURPOSE:To reduce the retrieval time, and establish the communication path at the time of connecting a recall in a short time and to improve the serviceability to the user by allowing a mobile terminal station to send a recall request while adding communication connection form information thereto. CONSTITUTION:Upon the receipt of a recall request from a base station B2, when communication connection form information 2 is called, a central management station C1 retrieves a communication path in which a T-ID of a communication path management data and a T-ID3 in the recall request are coincident. When the information 2 is received, the central management station C1 retrieves a communication path in which a R-ID of a communication path management data and a T-ID3 in the recall request are coincident. The central management station C1 obtaining the communication path set at present references the communication path management data to establish a new communication path to be used to a mobile destination (base station B2), sends the recall reply to the base station B2 and mobile terminal equipment station T1 to revise the communication path thereby continuing the communication. Thus, the time of the central management station retrieving the communication path so far is reduced and the communication path at recall connection is established in a short time and the service performance to the user is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wireless transmission system, and more particularly to a wireless transmission system for transmitting data packets in a zone-based mobile radio system.

[Conventional technology]

Generally, in such a mobile radio system, each base station Bl, B2 manages a service zone Zl, Z2, respectively, and is connected to each base station Bl, B2 by a dedicated line, as shown in FIG. Central control station C1 that manages the entire system
It is structured so that there is. In Figure 2, zone Z
1 shows a state in which mobile terminal station T1, which is communicating with a partner station through base station B1 and central control station C1, moves to zone Z2. The central control station C1 manages subscriber information and communication routes, and sets communication routes in accordance with call origination and call reception requests from each subscriber.

Generally, in mobile radio systems, due to the unique characteristics of radio communication, it is impossible to prevent a person holding a receiver from eavesdropping on the communications of others, and the system does not have any means of protection against jamming radio waves. However, if it is possible to infiltrate the system's network without permission and use the system without permission, it will cause inconvenience to authorized subscribers or use the system for free, so it is necessary to request connection from wireless subscribers. Except for some data when making a call or requesting a re-call, encoded data is used in the wireless section to prevent unauthorized access to the network. FIG. 5 shows the format of a re-call request message in an example of a conventional wireless transmission system. The central control station manages the key for decoding encoded data in correspondence with the subscriber's individual number (referred to as ID), and the base station decodes uplink data from the mobile terminal station or The downlink data to be transmitted from the station to the mobile terminal station is encoded.

FIG. 3 is a diagram showing a re-calling sequence from the mobile terminal station T1 in the mobile radio system shown in FIG. When the base station B2 receives the re-call request from the mobile terminal station T1, it requests the re-call key from the central control station C1, including checking the validity of the re-caller (re-call key request), and performs the central control. (Recall key response) sent from the station C1 (Recall key response) The encoded part of the recall request is decoded using a key unique to the recaller, and a recall request is sent to the central control station C1.

The central control station C1 searches the communication route management data for the currently set communication route based on the calling party's individual number (T-ID in FIG. 5) included in the re-calling request, and connects the communication route. As shown in FIG. 4, the communication route management data consists of a communication route number, a calling party individual number (T-ID), and a destination individual number (referred to as R-ID). Central control station C1
From the communication route management data, it is possible to know which communication route is used by which subscriber and which subscriber to communicate.

By the way, the following two types of communication connection forms can be considered. One is when the mobile terminal station issues a call and establishes a communication path from the viewpoint of the mobile terminal station, and the other is when the communication path is established by receiving an incoming call instruction from the mobile terminal station. Central control station C
In the former case, in the communication route management data managed by No. 1, the individual number of the mobile terminal station is registered in the T-ID, and the individual number of the other party is registered in the R-ID. In the latter case, the individual number of the mobile terminal station is registered in the R-TD, and the individual number of the originator is registered in the T-ID. Therefore, in response to the re-calling request, the central control station C1 determines that the re-calling source ID < T-I in FIG.
D) and all IDs of T-ID and R-ID in the communication route management data to find the communication route before movement, and change the communication route to the movement destination (base station B2 that made the re-call request). Changes were made and communication continued.

[Problem to be solved by the invention]

In the conventional wireless transmission method described above, in a recall connection, the central control station collects all I/O information from communication path management data based on the T-ID in the recall request sent from the mobile terminal
D has to be searched, and the search time is required, so it takes time to establish a communication path when connecting a re-call, and this has a serious disadvantage in that the serviceability to the user is poor.

[Means to solve the problem]

In the wireless transmission system of the present invention, a plurality of base stations connected to a central management station via a dedicated line manage one corresponding service zone, and a plurality of mobile terminal stations move between a plurality of service zones and In a wireless transmission method, the mobile terminal station communicates through one of the mobile terminal stations and the central management station, and the central management station specifies which of a plurality of communication paths the mobile terminal station uses to communicate. When the mobile terminal station sends a re-calling request to continue communication through a different base station than before, the mobile terminal station determines whether the previous communication was the first call from its own station or whether the call was from the central control station side. The central control station determines, based on the communication connection form information, the communication connection form of the mobile terminal station that sent the received re-calling request. Using the result, the above-mentioned 5th communication route designation is changed.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

1st. The figure is a diagram showing the format of a re-call request message in one embodiment of the present invention. This embodiment is applied to the mobile radio system shown in FIG.

Mobile terminal station T1, which was communicating through base station B1, detects a deterioration in the reception level due to movement from zone Z1 to zone Z2, and issues a re-call request to base station B2, as shown in FIG. In the re-call request message shown in Figure 1,
] is a pattern that indicates that this message is a re-call, and 2 is a pattern that indicates that the communication performed by the mobile terminal station T1 is a call originating from the own station. The communication payment type information indicates which of the incoming calls caused the establishment of the communication route, 3 represents the individual number of the mobile terminal station T1, and 4 represents the individual number of the other party.

Base station B2 receives a re-calling request from mobile terminal station T1 and requests a re-calling key to central control station CI, and central control station C1, which received this re-calling key request, checks the validity of mobile terminal station T1. and sends a re-call key response to the base station B2, and the base station B2 that received the re-call key response transmits the re-call key response to the central control station C2.
The process of requesting re-calling is the same as in the conventional example described above.

When the centralized control station C1 receives a re-calling request from the base station B2, if the communication connection form information 2 shown in FIG. ID
A search is made for a communication route that matches TID3 in the re-call request. When there is an incoming call, a search is made for a communication route in which the R-ID in the communication route management data shown in FIG. 4 matches the T-ID3 in the re-call request. The central control station C1, which has determined the currently set communication route in this way, refers to the communication route management data to establish a new communication route to be used at the destination (base station B2), and sends a re-call response to the base station. Station B2
It is also sent to the mobile terminal station Tl to change the communication route and continue the communication. In addition, when changing this communication route, the central control station C1 sends a re-call disconnection request (not shown in FIG. 3) to the base station B1, and disconnects the previous communication route.

〔Effect of the invention〕

As explained above, the present invention enables a mobile terminal station to add communication connection type information to a re-call request and send it. By determining whether the call is due to a call from someone else based on the communication connection form information, the central control station can greatly reduce the time it takes to search for the previous communication route, and can make it easier to establish a communication route when a re-call is connected. This can be done in a short time and has the effect of improving serviceability for users.

FIG. 2 is a diagram showing the format of a re-call request message in the above-mentioned conventional example.

2... Communication connection form information, Bl, B2... Base station,
C1...Centralized control station, Zl, Z2...Zone.

Claims (1)

[Claims] A plurality of base stations connected to a central management station via a dedicated line each manage one corresponding service zone, and a plurality of mobile terminal stations move between a plurality of service zones and manage one of the base stations and the central management station. In a wireless transmission method in which the mobile terminal station communicates through a central control station and the central control station specifies which of a plurality of communication routes the mobile terminal station uses to communicate, the mobile terminal station that was communicating until now A communication connection form that identifies whether the communication up to now was the first call from the own station or the call from the central control station in response to a re-call request sent to continue communication through the base station different from the base station. The centralized control station determines the communication connection form of the mobile terminal station that sent the received re-calling request based on the communication connection form information, and uses the result of this judgment to determine the communication route. A wireless transmission method characterized by changing specifications.