JP2805570B2 - Mobile communication method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication method in a mobile communication system including a mobile switching center, a plurality of radio base stations, and a plurality of mobile terminals.

[0002]

2. Description of the Related Art In a conventional mobile communication system, as shown in FIG. 4, a mobile communication switching center sends a communication line voice and a codec to a radio base station widely distributed in each region in accordance with its radio channel. They were physically associated. For this reason, there is a drawback that, when trying to realize a service in an area with a low subscriber density, a large number of communication lines and voice codecs are required even if the traffic volume accommodated by the mobile communication switching center is the same.

A simple numerical example showing this is shown below with reference to FIG. It is assumed that the capacity of the mobile communication exchange is 50 Erl and the calls are evenly distributed in the service area. As shown in FIG. 4, it is assumed that an area having a high subscriber density has a traffic volume of 10 Erl per zone. Since the mobile communication exchange can accommodate 50Erl, it can accommodate 5 wireless zones. Since 10 Erl per wireless zone, the required number of lines is 16 lines per wireless zone when calculated using Erlang B formula at a call loss rate of 3%. Since the codec circuit is provided for the line, 16 codec circuits are required per wireless zone. Since the exchange accommodates 5 wireless zones, the number of codec circuits required to accommodate 50 Erl subscribers is 16 circuits / zone × 5 zones = 8
0 circuits.

As shown in FIG. 4B, it is also assumed that an area having a low subscriber density has a traffic volume of 5 Erl per zone. Since the mobile communication exchange can accommodate 50Erl, 10
Can accommodate wireless zone. Since 5 Erl per wireless zone, the required number of lines is 10 when calculated using the Erlang B formula at a call loss rate of 3%. Since the codec circuit is provided for the line, 10 codec circuits are required per wireless zone. Since the exchange accommodates 10 zones, the number of codec circuits required to accommodate 50 Erl subscribers is 10 circuits / zone × 10 zones = 100
It becomes a circuit.

[0005]

From a simple numerical example, 80 codecs are used when 50Erl is accommodated in a high subscriber density area, and 100 codecs are used when 50Erl subscribers are similarly accommodated in a low subscriber density area. You know what you need. As described above, the conventional configuration has a disadvantage that the system cannot be configured more economically in an area with a low subscriber density than in an area with a high subscriber density.

An object of the present invention is to minimize the increase in the number of required resources such as a communication line between a mobile communication exchange and a radio base station, a codec circuit, etc., and to economically configure a mobile communication system. It is to provide a communication method.

[0007]

According to the present invention, a mobile communication switching center converts a signal with a signal converter, converts the converted signal into a frame, and uses, for each frame, an apparatus used for the signal conversion. The signal conversion device information to be specified and the radio base station to which the frame is to be transmitted and the radio channel information to specify the radio channel of the radio base station to which the frame is to be transmitted are added. Each frame is multiplexed and transmitted to the corresponding radio base station, and the radio base station transmits a signal from the switching station for each frame on a radio channel corresponding to the radio channel information attached to the frame, and transmits a signal from the mobile terminal. The signal is framed, and each frame is provided with the same signal conversion device information attached to the frame for the transmission radio channel, and is sent to the mobile switching center. Shin and supplies the mobile services switching center to the signal conversion device indicated by the signal conversion device information attached to it each frame of the received signal.

[0008]

FIG. 1 shows an example of a mobile communication system to which the present invention is applied. Each of the radio base stations 200-1 to 200-k is provided one by one for each zone.
-L can use the radio channels 201-l to 201-n, and other base stations also have a plurality of radio channels to be used. The radio channel 201 in the base station 200-1
Wireless devices 202-1 to 202 in correspondence with -l to 201-n
-N is provided, and each of the wireless devices 202-1 to 202-n
In accordance with the present invention, the address copying circuit 2 holds the codec number sent from the mobile communication switching center and adds the code number to the information sent to the mobile communication switching center.
03-l to 203-n. Wireless device 202
The information received by -l to 202-n is multiplexed by the multiplexing circuit 204 and transmitted to the communication line 206-l. The signal from the communication line 207-1 is distributed by the distribution circuit 205 to convert the information frame into an address copy circuit 203-1 to an address copy circuit 203-1 to ... based on the radio channel number in the frame.
203-n.

Each of the radio base stations 200-1 to 200-k transmits multiplexed information to the concentrator 210 through the communication lines 206-1 to 206-k, and transmits the multiplexed information from the concentrator 210 to the communication line 207. −l to 207-k
To receive through. The signal on the communication line 206-1 is shown in FIG.
2A, the signals are multiplexed in the order from the frames 208-1 to 208-n corresponding to the wireless channels 201-l to 201-n, respectively, and the signal on the communication line 207-1 is wirelessly multiplexed as shown in FIG. Channel 201-l to 201-
n and corresponding frames 209-1 to 209 -n
Are multiplexed in that order.

The concentrator 210 is connected to the radio base stations 200-1 to 200-1.
This is for distributing / concentrating information to be exchanged between the mobile communication switching station 217 and the mobile communication switching station 217. The multiplexed circuit 211 sends the framed information transmitted from the communication lines 206-1 to 206-k. Multiplexed based on the codec number in the mobile communication exchange 217 via the communication line 213. The distribution circuit 212 converts the information of each frame sent from the mobile communication switching center 217 via the communication line 214 into any one of the communication lines 207-1 to 207-k corresponding to the wireless base station number in the frame. Distribute crab. As shown in FIG. 2C, the signals on the communication line 213 are multiplexed with frames 215-l to 215-m in that order in accordance with the codec number.
As shown in FIG.
216-m are multiplexed in that order.

In a signal conversion circuit 218 such as a codec device in the mobile communication switching center 217, information transmitted through the communication line 213 is converted by the distribution circuit 219 based on the codec number in the frame into the codec circuits 222-1 to 222-2.
22-m, and the signals from the address information adding circuits 221-1-221-m are multiplexed by the multiplexing circuit 220, sent out to the communication line 214, and sent to the address information adding circuits 221-1-221. At −m, the signals from the codec circuits 222-1 to 222 -m are framed, address information is added, and the
-L to 222-m compress the audio signal into the mobile communication and vice versa. Signal conversion circuit 218
The control of each section is performed by the control circuit 223. The codec circuits 222-1 to 222-m are the communication path switches 2
The telephone line 226 is exchange-connected with the telephone set 226, and the call path switch 224 is controlled by the call processing device 225.

An embodiment of the present invention will be described below with reference to FIG. Now, a description will be given on the assumption that the mobile terminal 227 is moving to a wireless zone controlled by the wireless base station 200-1. When the call processing device 225 of the mobile communication switching center 217 detects an incoming call from the telephone set 226 to the mobile terminal 227, it performs a general call and the mobile terminal 227 sets the radio base station 200-1.
Knowing that you are in the zone is the same as the conventional method.

[0013] The call processing device 225, having learned that the mobile terminal 227 is in the zone of the radio base station 200-1, searches a management table provided in a processing device not shown in the figure and searches the management table for the radio base station 200-1. Is selected, and the management table corresponding to the wireless channel is set to the in-use state. Similarly, a codec circuit that is not currently being used is selected from the codec circuits 222-1 to 222 -m of the signal conversion device 218, and the management table of the codec circuit is set to a use state. Here, a description will be given assuming that the wireless channel 201-1 and the codec circuit 222-1 are selected. The call processing device 225 notifies the mobile terminal 227 of the selected wireless channel through a control line (not shown), and the wireless terminal 227 switches to the designated wireless channel in the same manner as in the conventional system.

The call processing device 225 that has selected the free radio channel 201-1 and the free codec circuit 222-1 connects the codec circuit 222-1 and the telephone 226 by controlling the communication path switch 224, and connects the signal conversion device 21.
8 to the selected codec circuit 222-
l, the number of the wireless base station 200-l, and the number of the wireless channel 201-l.

The number of the codec circuit 222-1, the number of the radio base station 200-1, and the radio channel 201-1
The control circuit 223 having received the number of the base station 200 transmits the number of the radio base station 200-1 to the address information adding circuit 221-1 corresponding to the codec circuit 222-1 from the codec circuit number.
The number of the wireless channel 201-1, the codec circuit 222
-L number is notified.

The telephone 22 through the communication path switch 224
6 is connected to the telephone 22.
6 is converted into a digital signal compressed for mobile communication and sent to the address information adding circuit 221-1. The address information adding circuit 221-1 is provided with a codec circuit 222-1 according to the signal format shown in FIG. 2E.
Is divided into frames and set in the communication information 304, the number of the wireless base station 200-1 notified from the control circuit 223 to the base station number 301, and the number of the wireless channel 201-1 to the wireless channel number 302. The number of the codec circuit 222-1 is set to the codec number and transmitted to the multiplexing circuit 220. Call processing device 2
Reference numeral 25 indicates that the address information adding circuit is instructed through the control circuit 223 to transmit a signal frame with a predetermined radio base station number (for example, 0) for an empty codec circuit.

The multiplexing circuit 220 is an address information adding circuit 2
The signal frame received from 21-1 is inserted into frame 216-1 corresponding to the codec number of communication line 214 and transmitted to concentrator 210. Similarly, each signal frame from the address information adding circuits 221-1 to 221-m is inserted into a frame in the communication line 214 corresponding to the codec signal.

Upon receiving the signal frame 216 sent from the communication line 214, the distribution circuit 212 of the concentrator 210 receives the communication line (here 207) corresponding to the wireless base station number 301 in the frame (here, 216-l). −l)
The signal frame is transmitted to the radio base station (here, 200-1) in the frame (here, 209-1) corresponding to the wireless channel number 302 of the above. When the wireless base station number 301 in the signal frame received from the communication line 214 is a predetermined wireless base station number (for example, 0), the distribution circuit 212 discards the frame.

The distribution circuit 205 of the radio base station 200-1 receives the signal frame 209-1 received from the communication line 207-1.
Is the wireless channel number 3 set in the signal frame.
02 is sent to the address copy circuit 203-1 corresponding to "02". Address copying circuit 203-1 receiving signal frame
Extracts the communication information 304 in the signal frame and sends it to the mobile terminal 227 via the wireless channel 201 through the wireless device 202-1. As described above, the mobile terminal 227 can receive a signal from the telephone 267.

The signal from the mobile terminal 227 is received by the radio 202-1 through the radio channel 201-1 and is input to the address copying circuit 203-1. The address copying circuit 203-1 decomposes the received signal into frames according to the signal format 305 from the radio base station to the mobile communication switching station shown in FIG. 2F, sets it into communication information 307, and is sent from the distribution circuit 205. The number of the codec circuit 222-1 of the signal frame 209-1 is assigned to the codec number 30.
6, the signal frame is assembled and sent to the multiplexing circuit 204. When the wireless device 202 is not used, the corresponding address copying circuit 203 sets a specific codec number (for example, 0), assembles a signal frame, and sends the signal frame to the multiplexing circuit 204.

The multiplexing circuit 204 is provided for each address copying circuit 20.
The signal frames transmitted from 3-1 to 203-n are sequentially multiplexed into frames of the communication line 206-1 and transmitted to the concentrator 210. Here, the signal from the address copying circuit 203-1 is The description will be made assuming that the frame is placed in the frame 209-1. Multiplexer 21 of Concentrator 210
1 corresponds to the codec number set in the codec number 306 of the signal frame transmitted from the communication line 206-1 and transmits the signal of the frame 209-1 to the communication line 213.
To the mobile communication switching center 2
17 is sent. When the codec number is a predetermined specific number (for example, 0), the frame is discarded.

When receiving the signal frame 215-l on the communication line 213, the distribution circuit 219 of the signal converter 218 sends the communication information 307 to the codec circuit 222-1 corresponding to the codec number 306 in the signal frame.
The codec circuit 222-1 decompresses the audio signal of the received signal and sends the signal to the telephone 226. As described above, a signal is transmitted from the mobile terminal 227 to the telephone 226.

In FIG. 1 used in the above description, the signal frame transmitted on each communication line (206, 207, 213, 214) is properly time slotted in order for the radio channel and the codec circuit. It is clear that this signal frame does not depend on the time slot position, and the signal frame is stored in a buffer at the time when the generation / assembly of the signal is completed, and is sequentially transmitted to the communication line in units of the signal frame. It is clear that this can be achieved. In this case, when a codec circuit or a wireless device is not used, it is not necessary to send a dummy signal in which a specific number is set as a base station number / codec number.

As described above, according to the present invention, it is not necessary to make the radio channel and the codec circuit fixedly correspond one-to-one through the communication line. You can do it as you like.

[0025]

As described above, according to the present invention, it is not necessary to physically correspond a communication line or a codec circuit to a wireless channel on a one-to-one basis. Since the channels can be used in common, even when a service is provided in an area where the subscriber density is low, an increase in the number of required resources can be suppressed, and a mobile communication system can be configured economically.

FIG. 3 shows a calculation example of the number of codecs required in the configuration of FIG. 1 under the same accommodation conditions as in the configuration example of the conventional system shown in FIG. 4B (example in the case where the subscriber density is low). When the method of the present invention is applied, any codec circuit can be used in common for each radio base station. Therefore, it is only necessary to prepare a number that satisfies the blocking loss with a total traffic volume of 50 Erl accommodated in the exchange. Since the codec circuit is used in common by each radio base station, even if the call loss rate is set as very low as 0.1%, there are 71 circuits obtained by the Erlang B formula.

From the above, when the switching center accommodates a traffic volume of 50 Erl, the conventional system requires 100 circuits from FIG. 4B, but the system employing the method of the present invention requires 7 circuits from FIG.
One circuit is provided, and the number of necessary codec circuits can be greatly reduced. Further, according to the method of the present invention, even if the number of radio base stations changes, the number of necessary codec circuits can be limited only to the accommodated call volume per concentrator, so that it is hardly affected by the subscriber density and compared with the conventional method. It is possible to economically configure a mobile communication system without being affected by the subscriber density.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a mobile communication system to which the present invention is applied.

2A to 2D are diagrams showing a frame configuration of a communication line in FIG. 1, and E and F are diagrams showing a signal format.

FIG. 3 is a diagram showing a calculation example of the required number of resources to which the present invention is applied.

FIG. 4 is a diagram showing a system configuration to which a conventional mobile communication method is applied, and a calculation example of a required number of resources.

Claims (1)

(57) [Claims] 1. A communication method for a mobile communication system comprising a mobile communication switching center, a plurality of radio base stations, and a plurality of mobile terminals, wherein the mobile communication switching center converts a signal with a signal converter, and converts the signal. The signal is framed, and for each frame, signal conversion device information for specifying the device used for the signal conversion, the radio base station to which the frame is to be transmitted, and the radio base station to which the frame is to be transmitted. The wireless base station adds the wireless channel information specifying each wireless channel, multiplexes frames for the same wireless base station, and transmits the multiplexed frames to the corresponding wireless base stations. The signal transmission device information attached to the signal transmitted to the terminal is added and transmitted to the mobile communication switching center, and the mobile communication switching center transmits the signal from the radio base station to this. Mobile communication method and performing an inverse transform is supplied to the signal conversion apparatus identified by pressurizing the signal conversion apparatus information.