JPH04287431A - Mobile body communication system - Google Patents

Abstract

PURPOSE:To realize the mobile body radio communication system in which a speech radio channel in a radio zone is effectively utilized. CONSTITUTION:When both outgoing/incoming mobile bodies 3a,3b are in existence in a same radio zone 4 in the mobile body communication system in which plural base stations 2 form the radio zone 4 and an exchange station 1 is in existence in the middle, the exchange station 1 gives only one voice talking channel to the zone 4 so that both the outgoing/incoming mobile bodies 3a,3b make direct communication. Thus, the radio channel for talking in the radio zone is effectively used.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system for communicating between a plurality of mobile units via a switching center.

0002

2. Description of the Related Art FIG. 7 is a block diagram showing a conventional mobile communication system. Build a communication system. 2 is a plurality of wireless base stations (hereinafter referred to as FB
), one wireless zone 4 is used as a service area, and a transceiver is provided for communicating with mobile objects within the zone. 3a and 3b are mobile units (hereinafter referred to as ML) within one wireless zone 4, and Scha and Schb are MLs.
A wireless channel for voice calls given to 3a and 3b.
It consists of two frequency signals: upstream and downstream. In addition to the above radio channels, uplink and downlink control channels (hereinafter referred to as Cch) are provided.

Next, the operation will be explained. FIG. 8 shows a connection sequence from when a call is made from one ML to when a call is established. Normally, each ML 3a, 3b is in an idle state and ready to receive the above Cch. Now, within zone 4 that one FB2 is in charge of, ML3
Assume that a makes a call to ML3b in the same zone. First, ML3a makes a “call request” using the upstream Cch.
issue. CC1 receives this via FB2, and then
C1 returns a response using the downstream Cch, and also designates channel Scha as a free communication channel. The calling side ML3a receives the instruction and switches to channel Cch.
to Scha. Next, ML3a uses this Sch
Use a to issue a dialing signal for the other party. CC this
1 through FB2, CC1 sends the called party ML3
ML3b using the downlink Cch of zone 4 where b exists.
Make a call. When ML3a and ML3b exist in the same zone 4, the same Cch is used.

ML3b responds to the above call with an upstream Cc
When a response is returned by h, CC1 instructs Schb as the communication channel, and the communication channel shifts from Cch to Schb. On the other hand, ML3a uses RBT after sending the dial signal.
It is in a receiving state, and if ML3b responds, it will receive a "reply from the other party". Then, ML3a uses Scha, and ML3b uses Sch
Two different Scha,S in the same zone 4 using b
A communication state via CC1 and FB2 is achieved using chb.

[0005]

[Problem to be Solved by the Invention] Since the conventional mobile communication system is configured as described above,
Even if there are both incoming and outgoing MLs 3a and 3b within the zone, Scha and Schb are the radio channels within the zone.
There was a problem in that two pieces had to be used. In mobile communications, there are restrictions on the use of wireless channels, and they are positioned as one of the most valuable resources when building a system, so making effective use of the limited number of wireless channels is a major challenge. It has become one.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a mobile communication system that can effectively use radio channels within a zone.

[0007]

[Means for Solving the Problem] In the mobile communication system according to the invention of claim 1, when a calling side mobile body and a called side mobile body exist in the same wireless zone, a control channel A call request, a response from the called party, and a wireless channel instruction are made via the above-mentioned switching center, and then a call is made to the mobile unit of the calling party using the designated wireless channel. This allows direct communication with the mobile unit on the side.

[0008] The mobile communication system according to the invention of claim 2 is provided with a switch for switching between duplex call/simplex call and a switch for switching transmission/reception in the simplex call in the communication device provided in the mobile body, Communication is performed between a plurality of mobile bodies using one frequency within the wireless zone.

[0009]

[Operation] In the mobile communication system according to the invention of claim 1, when calling a called mobile body, if the calling mobile body is in the same zone, both mobile bodies communicate through one radio channel. , wireless channels within the zone can be used effectively.

[0010] In the mobile communication system according to the invention of claim 2, one frequency is given to a plurality of specific mobile groups, and the channel of that frequency is used within the group to perform simplex calls by press talk while switching switches. Therefore, wireless channels can be used effectively.

[0011]

[Example] Example 1. An embodiment of the invention according to claim 1 will be described below with reference to the drawings. In FIG. 1, the same reference numerals as those in FIG. 7 indicate the same components, and all the components including other parts not shown are the same as those of the conventional device. What is different from the conventional communication form is that in the figure, when calling/incoming MLs 3a and 3b exist in the same zone 4, only one Scha is used as a wireless channel to communicate between ML3a and ML3b.
This means that direct calls can be made between them.

Next, the operation will be explained. The connection sequence from the call origination to the conversation state shown in FIG. 2 will be explained. The sequence from ML3a making a call to ML3b returning a response is the same as the conventional one shown in FIG. Next, when CC1 recognizes that ML3a and ML3b exist in the same zone 4, it uses the downlink Scha for ML3a,
Performs "transmission instruction" for uplink Scha. At the same time ML3b
For , specify Scha. When the ML3b receives this, it enters a monitoring state in which it can receive the uplink Scha transmission signal transmitted by the ML3a by reversing the transmission frequency and reception frequency when using the normal Scha. Normally, the transmission power and reception sensitivity of ML3a and ML3b are low in a call via FB2, so communication between ML3a and ML3b cannot be performed unless they are close to each other even within the same zone 4. Therefore, CC1 is the downstream Scha and the upstream Sc of ML3a
While instructing to gradually increase the transmission power of ha,
Wait for L3b monitoring results.

[0013] The ML3b monitors the upstream Scha, and when it becomes ready to receive, uses the downstream Scha to "receive".
ML3a is directly notified of this fact. M who received this
L3a sets the “call start” timing to M on the upstream Scha.
Send directly to L3b and then initiate a direct call using Scha. Note that if ML3b cannot receive the upstream Scha of ML3a, CC1 measures time using a certain timer value. If it is determined that "reception is not possible", the call is started by giving Schb to ML3b as before.

Example 2. In the above embodiment, a duplex call with simultaneous sending/receiving is shown, but one frequency f1 is given to a specific mobile group within the zone, and within the group, for example, personal dotted line or taxi radio etc. In the form, the above one frequency f1
If it is possible to make simplex calls using PressTalk, frequencies can be used even more efficiently. An embodiment of the invention of claim 2 in this case will be described below with reference to FIG. In FIG. 3, 3c to 3f are MLs in one zone 4, each of which is equipped with the communication device shown in FIG. Reference numeral 11 indicates a press talk communication system constructed within zone 4. This press talk call system 11
Communication is performed within the network using one frequency f1.

FIG. 4 shows the configuration of the communication device.
The basic configuration includes a transmitter (hereinafter referred to as TX) 6, a receiver (hereinafter referred to as RX) 7, and an antenna 8, and here, a changeover switch is used for making a normal duplex call and a simplex press talk call. 9a
9c, and a press switch 10 for TX/RX switching. Figure 5 shows the connection sequence.

Next, the operation will be explained. Usually, M.L.
3c to 3f are in duplex call state, downlink Cc
h is being received. ML who wishes to have a press talk call
3c issues a "call request" using the uplink Cch. CC1 that receives this "call request" establishes a press talk communication system. First, the calling side ML3c is instructed to use the frequency f1 on the downlink Cch. The communication unit of the ML3c that receives this switches the press talk system selector switches 9a to 9c, and loads the frequency f1 to be used into both TX6 and RX7. Press switch 10 is “OFF”
In the state, the antenna 8 is connected to the RX7 side, and the f1 reception state is entered. When transmitting a call, the press switch 10 is turned "ON" to switch the antenna 8 to the TX 6 side, thereby transmitting.

On the other hand, in response to the “call request” from ML3c, CC1 responds to the ML (in this case, ML
3d to 3f) are called using downstream Cch. The MLs 3d to 3f that received this call return a “response” on the upstream Cch, and include their own I in the “calling signal” on the downstream Cch.
After confirming that D is gone, switch the communication switch 9a to 9c in the same way as ML3c, and set T.
Load f1 into X6 and RX7 and become ready for press talk. In this way, a press talk communication system is constructed within one zone.

Example 3. In the second embodiment, a case is shown in which a press talk communication system is constructed within one zone 4, but it is also possible to construct a telephone communication system in a similar manner across a plurality of zones. FIG. 6 shows a communication form according to an application example in that case. Components with the same reference numerals as those in FIG. 3 have the same configuration, and the sequence leading to connection is also the same as in FIG.
, the same as in FIG. In FIG. 6, the CC 1 is equipped with a preemption determination circuit 12 in order to enable telephone calls between a plurality of zones 4. FB2 monitors the carrier frequency f1 of the press talk system within its own zone 4, and when f1 is detected, CC
1 is notified to the pre-emption determination circuit 12 in 1. Pre-emption judgment circuit 12
Then, the audio signal of the earliest zone 4 should be looped back to the other zones 4. If there is a conflict, the one with the stronger transmission power will be detected by the FB2 within zone 4, so the one with the stronger transmission power will take priority. Between each zone 4, priority is given to the signal returned by the preemption determination circuit 12, and the F
B2 switches to TX and sends a signal to ML in zone 4.

[0019]

[Effect of the Invention] As described above, the invention of claim 1 is capable of transmitting a call request using a control channel when a calling side mobile body and a called side mobile body exist in the same radio zone. and a response from the called side and an instruction for a wireless channel are made via the switching center, and then the calling side mobile unit and the called side mobile unit are connected using the specified wireless channel. It was configured to communicate directly.

[0020] Furthermore, the invention of claim 2 is provided with a switch for switching between duplex call/simplex call and a switch for switching transmission/reception in the simplex call in the communication device provided in the mobile body, and a switch for switching between transmission and reception in the simplex call. The system was configured to communicate between a plurality of mobile bodies using one frequency.

Therefore, according to the inventions of claims 1 and 2, since communication between mobile bodies is performed through one channel, it is possible to effectively utilize the radio channels within the radio zone.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a mobile communication system according to an embodiment of the invention of claim 1.

FIG. 2 is a connection sequence illustrating the operation of the system.

FIG. 3 is a configuration diagram of a mobile communication system according to an embodiment of the invention of claim 2.

FIG. 4 is a configuration diagram showing a communication unit of a mobile object in the system.

FIG. 5 is a connection sequence showing the operation of a mobile communication system according to another embodiment of the present invention.

FIG. 6 is a configuration diagram of a mobile communication system to which the other embodiment of the present invention is applied.

FIG. 7 is a configuration diagram of a conventional mobile communication system.

FIG. 8 is a connection sequence showing the operation of the system.

[Explanation of symbols]

1 Switching station 2 Base station 3a to 3f Mobile station Scha Call radio channel 4 Wireless zone 6 Transmitter 7 Receiver 9a to 9c Duplex/Simplex changeover switch 10 Press switch 11 Press talk call system

Claims (2)

[Claims] 1. A mobile device comprising: a plurality of wireless base stations each having a service area in one wireless zone; and a switching center that controls communication between mobile units existing within the wireless zone via the base station. In a wireless communication system, when a calling mobile unit and a called mobile unit exist in the same wireless zone, a control channel is used to transmit the call request, the response from the called party, and the wireless channel. instructions through the switching center and radio base station, and then the calling mobile body and the called mobile body directly communicate using the designated radio channel. A mobile communication system characterized by: 2. A mobile body comprising a plurality of base stations, each of which has a service area in one wireless zone, and a switching center that exchanges and controls communications between mobile bodies existing within the wireless zone via the base station. In the communication system, the communication device provided in the mobile body is provided with a switch for switching between duplex call/simplex call and a switch for switching transmission/reception in the simplex call, and the communication device is provided with a switch for switching between duplex call/simplex call, and a switch for switching transmission/reception in the simplex call, and a plurality of frequencies are transmitted using one frequency within the wireless zone. A mobile communication system characterized in that communication is performed between mobile bodies.