JPH04287434A - Incoming call control system - Google Patents

Abstract

PURPOSE:To decrease number of receivers of mobile terminal equipments by devising the system to be used in common for plural mobile communication systems such as an automobile telephone system and an in-premises cordless telephone system so as to await an independent call from the plural mobile communication systems. CONSTITUTION:The mobile communication system employing the incoming call control system recognizes a timing when other system sends an incoming call signal by receiving the incoming call signal of the mobile communication system of the other system. While the other system does not send the incoming call signal, the incoming call of its own system is transmitted. Moreover, when the other system sends the incoming call signal and its own system sends the incoming call signal, the transmission of the same incoming call signal is repeated, A mobile terminal equipment selects a received frequency to receive the incoming call signal of the both systems. When the incoming call signals of the both are simultaneously sent, the incoming signal of the other system not implementing the incoming call control is received with priority.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to a plurality of mobile communication systems having overlapping service areas, such as a car telephone system and a local cordless telephone system. The present invention relates to an incoming call control method for a mobile communication system that allows users to receive and receive services.

0002

2. Description of the Related Art When a mobile terminal receives a call, a radio base station sends an incoming call signal through an incoming call control channel to perform simultaneous paging. When a mobile terminal is powered on and is not in the process of making a call, receiving a call, or registering its location, it is in a standby state for an incoming call, and selects the incoming control channel of the control zone in which the mobile terminal is located. Receive this. The called mobile terminal sends an incoming call response signal on the incoming call control channel and answers the general paging. In this way, a line is established between the radio base station and the mobile terminal to perform communication. Regarding this incoming call connection, please refer to "Car Telephone" supervised by Moriji Kuwahara (IEICE, 1985).
194-197. Regarding mobile terminal control during standby, please refer to page 181 of the same document.
It is detailed on page 185.

[0003] In digital mobile communications, one of a plurality of time-division multiplexed radio channels is sometimes used as an incoming call control channel for transmitting an incoming call signal. An example of such a frame structure is described on page 111 of ``Report of Research on Mobile Communication Systems in the Microwave Band'' (Radio System Development Center, February 1986). When adopting such a frame configuration, the mobile terminal receives only this incoming control channel during standby.

[0004] When multiple mobile communication systems, such as in-house cordless telephones and car telephones, provide services at the same location and the multiple systems independently register the location of mobile terminals and make calls, the frame structure described above is used. Even if the timing of the incoming control channels of the two systems overlaps, it is necessary to set the incoming control channels of each system so that one mobile terminal can receive services from multiple systems. In order to receive the information, the mobile terminal will be equipped with multiple independent receivers.

[0005]

However, if multiple receivers are used to simultaneously wait for calls from multiple systems as in the prior art, the number of receivers in the mobile terminal increases, making it difficult to downsize the mobile terminal. As described above, the conventional call termination control system has a problem to be solved regarding the number of receivers required in the mobile terminal. An object of the present invention is to solve the above-mentioned problems and provide a call termination control system that can answer calls from a plurality of mobile communication systems with a small number of receivers.

[0006]

[Means for Solving the Problems] The incoming call control method of the present invention is a incoming call control method for a first mobile communication system, which uses a plurality of time-division multiplexed radio channels in which at least a portion of the service area overlaps. There are one or more other mobile communication systems that send an incoming call signal for paging to the mobile terminal using some channels, and the mobile terminal communicates with the first mobile communication system with one or more other mobile communication systems. Connected as any mobile terminal in the system, the fixed station calls the mobile terminal using some of the multiple time-division multiplexed radio channels, and when the mobile terminal is in the standby state, the fixed station calls the mobile terminal intermittently. The first mobile communication system receives an incoming call signal for paging by receiving the incoming call signal, and the first mobile communication system receives the incoming call signal from the another mobile communication system, and the another mobile communication system sends out the incoming call signal. the first mobile communication system sends an incoming call signal at least once to the same mobile terminal to which the first mobile communication system is attempting to connect the incoming call, while another mobile communication system is not sending out an incoming call signal; It is characterized by being carried out.

[0007]

[Operation] A mobile communication system to which the incoming call control method of the present invention is applied (the first mobile communication system, hereinafter abbreviated as the own system) and another mobile communication system (hereinafter abbreviated as the other system). There are two ways to ensure that the mobile terminal receives both incoming call signals without exception: one is to have the own system make a call while avoiding the other system's incoming call signal sending time, and the other is to have the own system make a call while avoiding the other system's incoming call signal sending time. There is a method of retransmitting the incoming call signal in case of overlap without avoiding the time. First, the former will be explained.

[0008] Other systems transmit incoming call signals intermittently, but there are two cases in which intermittent call signal transmission is performed regularly;
It is conceivable that the time at which the incoming call signal will be sent is announced in advance. In either case, since the local system receives the incoming call control channel of the other system at its fixed station, it can know in advance the time when the other system will send out the incoming call signal. Therefore, if the incoming call signal of the own system is sent out while avoiding the sending time of the incoming call signal of the other system, the incoming call signals of the own system and the other system will not be sent out at the same time. Therefore, the mobile terminal switches both incoming control channels, and receives the incoming control channel of the other system at the time when the other system sends out the incoming call signal, and receives the incoming control channel of the own system at the time when the incoming call signal of the own system is sent out. do. Furthermore, when the time when the own system sends the incoming call signal of another system overlaps, the own system is prevented from sending out the incoming call signal, so that the mobile terminal preferentially receives the incoming call control channel of the other system.

Next, a method will be described in which the own system retransmits an incoming call signal when the incoming call signal transmission time of another system overlaps with the other system's incoming call signal transmission time. If the other system sends an incoming call signal at a different period than its own system, if the incoming call signal is sent without controlling to avoid duplication of the incoming call signal sending time with the other system, the other system and the incoming call signal will Sending times may overlap. At this time, when the own system receives the incoming call signal of the other system and detects that the other system and the other system have sent out the incoming call signal at the same time, the mobile terminal that receives the incoming call signal of the other system with priority receives the incoming call signal of the own system. The same incoming call signal is sent out repeatedly so that the call signal can be received. The mobile terminal switches and receives both incoming control channels,
When the incoming call signal sending times overlap, the sending of the incoming call signal by the own system is repeated, so by giving priority to receiving the other system, all incoming call signals are received without omission.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained in detail with reference to the drawings. FIG. 1 is a timing chart showing an embodiment of the incoming call control method of the present invention. In the figure, PG indicates an incoming call control channel that sends out an incoming call signal. The other parts are channels used for control such as channel switching during a call and for calls (data transmission). Other systems are 8
One of the TDMA channels is an incoming call control channel. Other frequencies are time-division multiplexed into 8 channels and are used for calls, etc., but since there is no incoming call control channel, they will not be discussed here.

FIG. 1A shows a first embodiment, in which the system has four time-division multiplexed channels on one frequency, one of which is used as an incoming control channel. Similar to other systems, there are multiple time-division multiplexed channels on other frequencies, but they will be omitted. The frame period is the same as other systems.

FIG. 2 is an example of a mobile communication system using the incoming call control method of the present invention. In the own system, the incoming call signal (frequency f
m) is received by the external base station 20 and sent to the switching center 30. In this way, the incoming call signals of the own system and other systems can be received, so the timing of the incoming call control channel can be known. The exchange then uses its own system's incoming control channel (
The transmission timing of each base station 40 is controlled so that the frequency fi) does not overlap with the incoming control channel of another system. In this embodiment, by making the frame period of the own system the same as that of other systems, even if the incoming call signal is always sent out at a constant period, the incoming call signal can be prevented from duplicating with that of the other system. Meanwhile, the mobile terminal receives incoming control channels of both systems while switching frequencies between fm and fi.

FIG. 1(b) shows a second embodiment, in which the system has three channels time-division multiplexed on one frequency, one of which is used as an incoming call control channel. The frame period is shorter than other systems. In this embodiment, as in the first embodiment, the transmission timing of each channel of the own system is controlled, but since the frame lengths are different, it is necessary to ensure that the incoming call signal transmission times of both systems do not overlap. . In FIG. 1B, the incoming call signal transmission times of both systems do not overlap in the first frame and the second frame, but they overlap when the own system sends an incoming call signal in the third frame. Since this can be predicted in advance, the own system avoids duplication by not sending an incoming call signal in the third frame. Since the fourth frame to the sixth frame do not overlap, an incoming call signal is sent. On the other hand, the mobile terminal receives the incoming call control channels of both systems while switching frequencies, but in the third frame, the mobile terminal is not supposed to send out an incoming call signal to avoid duplication of signal sending, so Receive the system's incoming control channel.

FIG. 2(c) shows a third embodiment, in which the channel multiplexing method and frame length are the same as in the second embodiment. In this embodiment, the own system does not predict in advance that the incoming call signal transmission times will overlap, and when it receives the incoming call signal of another system and the incoming call signals overlap, it sends the same incoming call signal again in the next frame. do. In this example, the third
Duplication occurs in the frames, but at this time, the same incoming call signal as in the third frame is sent again in the fourth frame. This method is effective when the sending cycle of incoming call signals of other systems is irregular.

[0015]

According to the present invention, the number of receivers in a mobile terminal can be reduced, making it possible to downsize the mobile terminal.

[Brief explanation of the drawing]

FIG. 1 is a timing chart showing an embodiment of the incoming call control method of the present invention.

FIG. 2 is a diagram showing an example of a mobile communication system using the incoming call control method of the present invention.

[Explanation of symbols]

10 Base station 20 of another mobile communication system
External base station 30 Switching station 40 Base station 50 Mobile terminal

Claims (1)

[Claims] Claims: 1. An incoming call control method for a first mobile communication system, wherein at least a portion of the service area overlaps, and a call is made to a mobile terminal using some channels of a plurality of time-division multiplexed radio channels. There are one or more other mobile communication systems that send out incoming call signals for the mobile communication system, and the mobile terminal is connected as a mobile terminal to both the one or more other mobile communication systems and the first mobile communication system, and The station calls the mobile terminal using a part of a plurality of time-division multiplexed radio channels, and when the mobile terminal is in a standby state, it receives an incoming call signal for paging by intermittently receiving it. , the first mobile communication system receives an incoming call signal from the other mobile communication system, detects the time when the another mobile communication system sends out the incoming call signal, and An incoming call control method characterized in that the system transmits an incoming call signal to the same mobile terminal to which an incoming call connection is to be made at least once while the other mobile communication system is not sending out an incoming call signal. .