JPS5847106B2 - Small capacity mobile communication system - Google Patents

Description

[Detailed description of the invention] TECHNICAL FIELD This invention relates generally to low capacity communication systems.

Although the present invention is intended to be applied to mobile communications, it can also be used as a communication system in depopulated areas, in developing areas, or as an emergency telephone in the event of a disaster.

In general, a mobile communication system includes a wired exchange EX connected to a public communication network, a mobile radio control device MTS connected to this via a trunk, and a radio communication base connected to the MTS for transmitting and receiving radio waves. It consists of a station B S- and a plurality of mobile units M.

Among these, the functions of the conventional mobile radio control device MTS, which is particularly important, are summarized as follows.

(1) Receiving function of M selection signal sent from EX,
A function to send a selection signal from MTS to M.

(2) Receiving function of selection signal sent from M and MTS
A function to send a selection signal from to EX.

(3) In the case of conventional large-capacity mobile communication systems, EX and M
Since a large number of line bundles and radio channels are required for communication between TSs, in order to improve the efficiency of line selection (increase the internal width of EX), EX uses all wireless channels of MTS and communication lines between EX and MTS. MTS has a low congestion exchange function so that even if any empty CT (outgoing trunk) or BWT (bidirectional trunk) is randomly selected, 9 connections can be made as long as all wireless channels are available. It becomes necessary.

(4) Generally speaking, as a feature of mobile communications, there are more incoming calls from EX and more outgoing calls from υM, so EX and MTS
The communication trunk between the two is expensive, and it is uneconomical to interface only with the WT.

Therefore, instead of using only a bidirectional BWT as an interface, a unidirectional but inexpensive OCT or ICT (ingress trunk) is used as an interface.

Furthermore, in a high-capacity system, the amount of communication between mobile subscribers increases, so it is difficult to make these calls via EX.
The traffic load of
It is preferable to make a loop connection inside S.

As mentioned above, as for MTS, in addition to the call trunk, the EX side terminal has MO8T, RGT, and MOR (symbols will be explained later).
, a return connection terminal is required, and the BS side must also accommodate IRT, RBT, and O8 (described below) in addition to the call trunk.

Furthermore, since the call trunk and the signal trunk are connected or switched during the call process, the MTS also needs a switching function.

By the way, in recent years, call services for mobile subscribers such as automobiles have made remarkable progress, but most of these are communication services that are targeted at around 150 mobile units, or at most around 400.

Therefore, if the call volume per mobile unit is 0.01 Erlang/device, the total call volume is 4 (=0.01 x 400) Erlangs, and the number of lines required to connect this with a block rate of 0.1. According to Erlang's loss load model, there are only 7 lines.

For such a small-scale communication system, it is economically unreasonable to use the mobile radio control device MTS, which was originally developed for a large-scale radio communication system as described above.

Therefore, the present invention aims to improve the above-mentioned drawbacks of the prior art, and its purpose is to provide an economical mobile communication system suitable for small-scale communication systems.

A feature of the present invention for achieving this object is to remove an expensive exchange switch from the mobile radio control device MTS, and to make the radio line and each line of the wired exchange fixedly correspond to each other.

This makes it possible to make the circuit of the mobile radio control device MTS into a module structure and add each line.

The present invention will be explained from the woman's point of view in comparison with the conventional technology.

First, Figure 1 shows a conventional mobile exchange system.

In the figure, 1 is a normal wired exchange EX. 2 is a conventional mobile radio control device MTS; 3 is a radio communication base station BS;
4 is an antenna A for transmitting and receiving radio signals, 5 and 26 are mobile subscribers M, 6 is a bidirectional trunk BWT, 7 and 1
8 is the incoming trunk ICT of a normal wired exchange, 8 and 2
0 is the normal outgoing trunk OCT of the wired exchange, 9 is the mobile M and yr'co selection signal receiving device IRT sent from the wired exchange EX, and 10 is the signal that informs the exchange EX that mobile subscriber M is being called. Notifying signal tone trunk RBT,
Reference numeral 11 denotes an MO8T which sends the selection signal of the mobile subscriber M received at 9 to the subscriber M via the base station BS. It has a receiving circuit for an activation confirmation signal sent from subscriber M to MO8T.

Reference numeral 12 denotes a receiving device MORT for receiving a selection signal necessary for mutual communication connection with a wired telephone subscriber or another subscriber M sent by the subscriber M, and a communication channel between the subscriber M and the control device MTS is set. It has a dial tone sending circuit that notifies the subscriber M that the subscriber M has received a dial tone.

13 is a bidirectional trunk MBWT for communication between the control device MTS and the base station BS.

14 is a sender O8T that sends a selection signal of the called wired telephone subscriber sent from subscriber M to the exchange EX in the case of a call from subscriber M; 15 is a control switch 5W116 of the exchange included in the control device MTS; Control unit CTL of the switch of the device MTS.

Reference numeral 17 denotes an MRGT having a function of sending a ringing signal tone to subscriber M5 and confirming the response of subscriber M5.

19 is an outgoing trunk MOGT used for outgoing calls from subscriber M5 to the fixed station; 20 is an outgoing trunk OCT;

21 is an incoming trunk MICT used for incoming calls from the exchange EX to the fixed station; 22 is a return line used for mutual communication between mobile subscribers M5 and M'26; 23 is a transmitter TX; 24
2 is a receiver RX, and 25 is a transmitter/receiver shared device TRM.

Next, referring to FIG. 1, the operation of a conventional mobile radio exchange will be explained using an example of an incoming call connection to a mobile subscriber M5.

When a call is made from exchange EX to M5, 0GT20
An incoming connection request comes to MTS 2 via.

When CTLl 6 detects this request through MICT21, CTLl6 drives 5w1s and connects MICT21 and I
Connect RT9.

Next, a mobile unit selection signal is sent from the exchange EX to the IRT9.

Upon receiving the selection signal, the CTL 16 selects the vacant MBW.
Select Tl 3 and set the train of MO8T11 and MBWTl 3.

Since the MBWT1 3 is installed in correspondence with the radio channel, it immediately starts selective calling of the mobile unit in this state.

Typical selective calling methods include a circular localization method and a circular non-localization method.

Circular localization is a method in which a base station sends out a free line signal to one of the available channels, and all mobile units other than those currently on a call wait on that channel. When used for a call, an idle line signal is sent to another empty channel, and mobile units that are not currently on a call switch channels one after another, stop switching at the channel where the idle line signal is received, and go back to standby. is an empty channel selection method that allows the channel to enter the state and prepare for the next call.

In the cyclic non-localization method, mobile units in standby mode are always automatically switched, and the base station sends signals to all available channels.

When selectively calling a mobile unit from the base station, the base station stops the empty line signal that was being sent for one of the empty channels, sends a switching stop signal, and calls all the mobile units that are performing automatic switching. This method sends out a calling signal after the time period for switching to that channel has elapsed.

Although there are some differences in the process of selecting an empty channel in both methods, the operation of the MTS after an empty channel is selected is the same.

When the selective call is completed, a selection signal is sent from MO8T11 to all mobile units waiting on the empty line via the train of MO8T11 and MBWT13.

When a called mobile among the waiting mobiles receives the selection signal, it sends an activation confirmation signal to MO8T11 via the base station.

When MO8T11 receives this startup confirmation signal, CTL1
6 restores the train of MBWTl3 and MO8TII,
Connect MBWTl 3 and MRGT17.

In this state, a paging signal is sent to the mobile object.

When the mobile body responds, a response signal is sent from the mobile body to the MRGT15, and this signal is sent to the CTL1 via the MRGT17.
6 detects.

When detected, the CTL 16 restores the train of MO8T11 and MBWTl3, newly sets the train of 0GT20 and MBWTl3, and starts a call.

Next, we will discuss communication connections between mobile subscribers when the cyclic localization method is adopted as the selective calling method.

When the mobile unit M5 makes a call, the mobile unit transmits MBWTl 3 using the channel on which the idle signal was sent from the base station.
Start.

When the CTL 16 detects an outgoing connection request from a mobile object,
Install MBWTl3 and MORTl2 trains.

Here, MORT sends a dial tone to the mobile object.

The MORT also receives a selection signal sent from the mobile after hearing the dial tone.

The called mobile is then paged in a manner similar to the terminating connection previously described.

When the called mobile object answers, a call train is set: mobile body→MBWT 13→return line 22→another vacant MBWB→mobile body, and the call begins.

As mentioned above, a communication system having the structure and operation described above is uneconomical for a small-scale system.

Next, a communication system according to the present invention that improves this point will be explained.

FIG. 2 is a block diagram showing the configuration of a mobile radio control device according to the present invention, and FIG. 3 is a configuration diagram of a bidirectional trunk according to the present invention.

31 is a normal wired exchange EX, and 32 is a mobile communication control device MTS.

As is clear from FIG. 2, the MT S 32 is composed of a bidirectional trunk BWT 33 and a common equipment section CCTL 34 that mainly controls signal tones.

Reference numeral 35 denotes a wireless transmitting/receiving base station BS, which is made up of a transmitter 36, a receiver 37, and a transmitting/receiving device 38.

Reference numeral 39 indicates a radio signal transmission/reception antenna A140 indicates a mobile subscriber.

41 is an incoming trunk ICT used for outgoing connection from subscriber M40, and 42 is an outgoing trunk OCT used for incoming connection from EX to M2O.

The BWT 33 includes an IR section 41a that receives the M2O selection signal sent from the EX 31, and this corresponds to the IR section 52 shown in FIG.

Similarly, 42a is a circuit MO8 for sending the selection signal accumulated in the IR section 41a to M2O, and is a circuit MO8 in FIG.
Corresponds to Part 8 55.

43 is R that sends a calling signal to the caller while calling M2O
Section B corresponds to section 08 76 in FIG.

44 is an MR having a function of sending an M2O call signal;
In the G section, the section 8 is connected to the RGO 8C section 78 in FIG.

Reference numeral 45 denotes an MOR that receives a selection signal sent from M2O when the M2O is connected for outgoing purposes, and corresponds to 56 in FIG.

Reference numeral 46 denotes a sender circuit O8 section which sends the selection signal stored in the MOH to the wired exchange as a selection signal, and corresponds to 59 in FIG.

Referring to FIG. 3, 51 is a detection relay A158 for detecting an incoming connection request signal sent from an ordinary wired exchange, and 58 is a trunk control circuit TCT that controls the sequence inside the bidirectional trunk.
L, 59 is a dial tone generating device DTO8C, which is sent out when a mobile subscriber makes a call, and 60 is a circuit DET that detects a call request, a response, and an end of a call from a mobile subscriber.

Reference numeral 74 indicates a fully closed indicator line SR of the wireless channel sent from the base station B533, and this information is sent to the exchange EX via the BI line 61 or the bridge circuit 62.

Next, the control relay and signal line of the trunk control circuit TCTL5B will be mainly explained.

61 is a gate relay that connects the selection signal sent from the exchange EX to the IR section 52 through contact a162 of relay A, which is contact q of relay Q, and 63 notifies TCTL5B that the selection signal has received all numbers, 64 is a control line for sending the selected number of M2O from the storage circuit of the IR unit 52 to the MOS through the communication line 77. 75 is a control line for sending the M2O response and call termination to TCTL 5B. This is a control line for notification.

65 is a gate relay r066 for sending the M2O selection signal stored in the MOS 55 to the D line and the E line, and 67 is a gate relay s for sending a calling signal from RGO8C of the signal sound control device to M2O.67 is M40 M2 when making a call
T indicates that the reception of the called party number sent from O has been completed.
A control line 68 is used to send the selection signal stored in the MOR 56 to the 08 unit 59 through the information line 69. u70 is a control line used to send a dial tone to the M2O when the M2O makes a call. A gate relay 72 is a gate relay for sending a selection signal to the wired exchange EX. VO73 is a gate relay W for sending a ringing tone of M2O to the wired exchange EX.

The relay contacts qyrss, u, and 72w explained above all operate according to the connection procedure of TCTL58, and 61, 63, 64° 67.6B, 74, and 75 are TCT
L5B is a control line that controls the BWT33.

Next, the present invention will be explained in detail using FIGS. 2 and 3.

The exchange EX31 and MTS32 are connected to 1CT41, 0GT42°BWT as in the conventional mobile communication system.

These trunks are accommodated in the BWT 33 of the MTS 32 in a one-to-one correspondence.

Furthermore, since the BWT33 also supports wireless channels, the wireless channel complete closure information is always available as BS35-)B
It is connected to the exchange EX via the route WT 33-+OGT 42 (including BWT).

Therefore, when a connection request is made from exchange EX to M2O,
Exchange EX31 has an empty radio channel 0GT.
42 and the A of BWT33 installed correspondingly.
Activate relay 51.

When TCTL5B is activated by contact a61 of the A relay, contact q62 is closed by the sequence circuit of TCTL5B, and the selection signal sent from EX31 is received in the train of EX31→BWT33→IR section 52.

When the selection signal is received, TCTL is sent through the control line 63.
sends a reception completion signal to

When the TCTL detects this signal, it sends an enable signal to the control line 64, and from the storage circuit of 1R52 to the MO8 section 55.
transfer the selection signal to.

This signal passes through the r65 contact driven by the TCTL58 and connects to the MOS 55-) r contact - +D, B via the path of the E line.
535.

Next, the RGO8C7B-+s contact 6
A calling signal is sent via the route 6→D and E lines.

Here, the W contact is closed under the control of the TCTL and a ringing tone is sent to the EX31.

When a called party response is detected on the path of A and B lines → r contact 65 → DET 60, the trunk section 4 of EX31eBWT33
A call is started on the +B5354+M40 train.

The end of the call is identified by the DET 60 in the same way as response detection, and is reported to the TCTL via the control line 75, and the BWT 33 is restored.

Next, a case will be described in which the mobile body M40 calls another mobile subscriber M1.

When the M2O makes a call, the MOR 56 detects the call from the M2O along the route M40→B535→MOR56, and the TCTL 5B is activated through the control line 67 from the MOR56.

The U relay operates according to the TCTL5B sequence, and the U
A dial tone is sent to M2O via the contact via the path of DTO8C59 → U contact → D and E lines.

The mobile subscriber hears this dial tone and sends out a called party selection signal.

This signal is received by MOR 56.

When the reception is completed, the MOR 56 notifies the TCTL 5B through the control line 67.

TCTL then activates MOR 56 via control line 68, and MOR 56 transfers the called party selection signal to the 0859 storage circuit via control line 69.

After the transfer is completed, the V contact closes under the control of TCTL5B and E
A called party selection signal is sent to X31.

In the case of a small-capacity mobile communication system, the volume of calls made by M2O with other mobile subscribers M' is small, so EX31
The increase in traffic added to this is slight and poses no particular problem.

Next, a comparative evaluation will be made regarding the economic efficiency of the conventional MTS described above and the MTS according to the present invention.

Assuming that the total number of mobile units is 150 and the average call volume per unit is 0.01 erlang when the call loss rate is 1/20, it is sufficient to have 4 wireless channels based on the loss load of erlang (1.525 erlang). .

Table 1 shows the required number of call trunks, registers, and senders, assuming that 60 calls are made from M2O and 40 calls are received.

Table 1 In other words, in the conventional method, the number of EX side terminals of MTS is E.
X side BWT, MO8T, RGT, MOR 10 terminals, M
The number of BS side terminals of TS is MBWT.

The 12 terminals of IRT, RBT, and O8 must be installed for a long time, and one-to-one correspondence between EX31 and BWT33, as well as wireless channels, cannot be established as in the present invention, so regardless of the size of mobile radio, MTS A replacement device will be required.

In addition, in the conventional system, BWT and MBW are used as call trunks.
The BWT according to the present invention requires four lines each, but only four lines are required for each register and sender.
It becomes necessary to carry them all in BWT33.

However, incorporating these into the BWT 33 means that the register, the relay for interfacing with the SW required for the sender, and the circuit for transmitting register information to the sender are all shared within the BWT, so the communication trunk The overall price of the signal and signal trunks will be rather cheap.

The features and effects of the small capacity mobile communication system according to the present invention described above will be described.

(1) In conventional MTS, there were many connections between call trunks and signal trunks, which required switching equipment with low congestion SW using a large number of expensive call contacts. By unifying the incoming trunk BWT and wireless channels, there was no need to install expensive female switching equipment at MTS, resulting in significant economic savings.

(2) Also, because the unification eliminates the need for complicated switch connections, there is no need for expensive CTLs with advanced logic functions.

(3) Various signaling devices have been built inside the BWT, but the functions that conventional signal trunks had individually are controlled by a common circuit inside the BWT (for example, 55 and 6 shown in Figure 3).
The main operation of the signal trunk is performed by opening and closing contacts at 3, 64, 67.68° and 69.74.75, and there is no special circuit), so the overall price of trunks is reduced.

(4) Due to the unification, the system scale can be easily expanded because wireless channels can be added simply by adding bidirectional trunk BWTs.

In particular, if the bidirectional trunk has a modular structure, lines can be added or removed on a module-by-module basis.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a mobile communication system based on conventional technology.
FIG. 2 is a block diagram of a mobile communication system according to the present invention, and FIG. 3 is a block diagram of a bidirectional trunk BWT and its related circuits according to the present invention. EX; wired exchange, MTS; mobile radio control device, BS;
Wireless communication base station, BWT; bidirectional trunk, CCTL
;Common equipment department, M;Mobile, ICT;Incoming trunk, OG
T: Outgoing trunk, TRK: Call trunk section, ■R: Selection signal receiving section, MOS: Sender section, RB: Transmitting section, M
RG: calling signal sending unit, MOR: receiving device, O8: sending circuit.

Claims (1)

[Scope of Claims] 1. A wired exchange, incoming trunks, outgoing trunks, and bidirectional trunks connected to the wired exchange, a mobile radio control device connected to the wired exchange via these trunks, and a mobile radio control device connected to the control device. In a mobile communication system having a plurality of radio communication base stations that transmit and receive radio waves, the mobile radio control device has a plurality of radio communication base stations fixedly corresponding to each of a plurality of radio lines and each line of a wired exchange. It has a space division circuit,
Each of the trunks is housed in each space division circuit in a one-to-one correspondence to be connected to the wired exchange, and each space division circuit receives a mobile subscriber selection signal sent from the telephone trunk section TRK and the wired exchange. a receiving section IR, a sending section MO8 that sends the signal to the mobile subscriber, a transmitting section RB that sends the mobile subscriber's call origination signal, a calling signal sending section MRG that sends the mobile subscriber's calling signal, and a mobile subscriber. 1. A mobile communication system comprising a receiving device MOR that receives a dial signal of a subscriber, and a circuit O8 that sends the dial signal to a wired exchange. 2. The mobile communication system according to claim 1, wherein the space division circuit has a modular configuration, and can be added or removed in units of modules.