JPH06237215A - Mobile communication method - Google Patents

Abstract

PURPOSE:To decrease the number of communication circuits and CODECs. CONSTITUTION:In an exchange 217, with respect to calling from a telephone set 226 to a mobile terminal 227, a base station 200-1 of its encircled zone, a free radio channel 201-1, and a free CODEC 222-1 are set, and a sound signal from the telephone se is converted to a signal by the CODEC. It is delimited to frames by a circuit 221-1, and a base station number, a channel number and a CODEC number are given to each frame, multiplexed with other signal frame by a multiplexing circuit 220 and sent to a line concentrator 210. In the line concentrator, each receiving frame is distributed and transmitted to each base station in accordance with its base station number. In the base station, each receiving frame is distributed, supplied and transmitted to each radio equipment corresponding to its channel number. A signal from the mobile terminal is converted to a frame by a circuit 203-1 in the base station, a number of the CODEC given by the exchange is added thereto and it is sent to the exchange through the line concentrator, converted to a sound signal by the CODEC corresponding to its CODEC number and reaches the telephone set.

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 communication line voices and codecs to wireless base stations widely distributed in each area. It was physically associated. For this reason, if a service is to be realized in an area where the subscriber density is low, there is a drawback that 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 volume of calls accommodated in 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 the area where the subscriber density is high has a call volume of 10 Erl per zone. Since the mobile communication exchange can accommodate 50 Erl, it can accommodate 5 wireless zones. Since 10 Erls per wireless zone, the required number of lines is 16 lines per wireless zone when the Erlang B formula is used and the call loss rate is calculated at 3%. Since the codec circuit is provided for each line, 16 codec circuits are required for each 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
It becomes 0 circuit.

Similarly, as shown in FIG. 4B, it is assumed that an area having a low subscriber density has a call volume of 5 Erl per zone. The mobile communication exchange can accommodate 50 Erl, so 10
Can accommodate a wireless zone. Since the number of lines required per wireless zone is 5 Erl, 10 lines are required if the call loss rate is calculated as 3% using the Erlang B formula. Since the codec circuit is provided for each line, 10 codec circuits are required for each 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 accommodated in a region where the subscriber density is high and 50Erl is accommodated, and 100 codecs are accommodated in the region where the subscriber density is low and 50Erl is similarly accommodated. I know what I need. As described above, the conventional configuration has a drawback that the system cannot be economically constructed in an area where the subscriber density is low as compared with an area where the subscriber density is high.

An object of the present invention is to make it possible to economically construct a mobile communication system by suppressing an increase in the number of necessary resources such as a communication line between a mobile communication exchange and a radio base station and a codec circuit. To provide a communication method.

[0007]

According to the present invention, a signal is converted by a signal conversion device at a mobile telecommunication switching center, the converted signal is framed, and a device used for the signal conversion is made for each frame. The signal conversion device information to be specified and the wireless base station to which the frame is to be sent and the wireless channel information to respectively specify the wireless channel of the wireless base station to which the frame should be transmitted are added, Each frame is multiplexed and transmitted to the corresponding radio base station, and the radio base station transmits the signal from the switching center for each frame on the radio channel according to the radio line information attached to that frame, Frame the signal and attach the same information as the signal conversion device information attached to the frame for the transmission radio channel to each frame and send it to the mobile communication 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. The wireless base stations 200-l to 200-k are provided one by one for each zone.
-L can use the wireless channels 201-l to 201-n, and other base stations also have a plurality of used wireless channels. The radio channel 201 in the base station 200-l
-L to 201-n and radios 202-l to 202
-N is provided, and each of the radios 202-1 to 202-n is provided.
According to the present invention, the address copying circuit 2 holds the codec number sent from the mobile switching center and adds the code to the information sent to the mobile switching center.
03-l to 203-n are provided. Radio 202
The information received by -l to 202-n is multiplexed by the multiplexing circuit 204 and sent to the communication line 206-l. A signal from the communication line 207-1 is distributed by the distribution circuit 205 based on the wireless channel number in the information frame, and the address copying circuits 203-1 to 203-l corresponding to the wireless channel are transmitted.
203-n.

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

The concentrator 210 is a radio base station 200-1.
Information for distribution / concentration of information transmitted / received between 200-k and the mobile switching center 217, and framed information sent from the communication lines 206-l to 206-k by the multiplexing circuit 211 It is multiplexed based on the codec number in the packet and transmitted to the mobile communication switching center 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 one of the communication lines 207-1 to 207-k corresponding to the radio base station number in the frame. Distribute to crabs. As shown in FIG. 2C, the signals on the communication line 213 are the frames 215-l to 215-m corresponding to the codec numbers multiplexed in that order. Similarly, the signal on the communication line 214 is also shown in FIG. 2D.
The frame 216-1 corresponds to the codec signal as shown in FIG.
.About.216-m are multiplexed in that order.

In the signal conversion circuit 218 such as a codec device in the mobile switching center 217, the information transmitted from the communication line 213 is distributed by the distribution circuit 219 based on the codec number in the frame to the codec circuits 222-1-2.
22-m, the multiplexing circuit 220 multiplexes the signals from the address information adding circuits 221-1 to 221-m, sends out to the communication line 214, and the address information adding circuits 221 to 221. -M, the signals from the codec circuits 222-1 to 222-m are framed and the address information is added.
Voice signals are compressed into the mobile communication by -l to 222-m, and vice versa. Signal conversion circuit 218
The control circuit 223 controls each part inside. The codec circuits 222-l to 222-m are communication path switches 2
24, the telephone line 226 is exchange-connected, and the speech 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. It is assumed that the mobile terminal 227 is now moving to the wireless zone controlled by the wireless base station 200-1. When the call processing device 225 of the mobile switching center 217 detects an incoming call from the telephone 226 to the mobile terminal 227, it makes a simultaneous call and the mobile terminal 227 makes the radio base station 200-l.
It is similar to the conventional method to know that you are in the zone.

The call processing device 225, which has learned that the mobile terminal 227 is in the zone of the wireless base station 200-l, retrieves a management table provided in a processing device not shown in the figure, and then searches the wireless base station 200-l. Select a wireless channel that is not currently used and set the management table corresponding to that wireless channel to the busy state. Similarly, a codec circuit that is not currently 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 the in-use state. Here, it is assumed that the wireless channel 201-1 and the codec circuit 222-1 are selected. The call processing device 225 notifies the selected wireless channel to the mobile terminal 227 through a control line (not shown), and the wireless terminal 227 switches to the designated wireless channel as in the conventional method.

The call processing device 225 selecting the idle radio channel 201-l and the idle codec circuit 222-l connects the codec circuit 222-l and the telephone 226 by controlling the speech path switch 224, and at the same time, the signal converter 21.
Codec circuit 222-selected in the control circuit 223 of No. 8
The l number, the wireless base station 200-l number, and the wireless channel 201-l number are notified.

The codec circuit 222-l number, the radio base station 200-l number, and the radio channel 201-l
The control circuit 223 having received the number of the wireless base station 200-l from the codec circuit number to the address information addition circuit 221-1 corresponding to the codec circuit 222-l.
Radio channel 201-l number, codec circuit 222
-Notify the number of l.

The telephone 22 is operated through the call path switch 224.
6 is connected to the telephone 22
The voice signal from 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 has a codec circuit 222-l according to the signal format shown in FIG. 2E.
The signal received from the device 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 is set to the base station number 301, and the number of the wireless channel 201-l is set to the wireless channel number 302. To the multiplexing circuit 220 after setting the codec number of the codec circuit 222-l to the codec number. Call processor 2
It is assumed that 25 instructs the address information addition circuit through the control circuit 223 to send a signal frame with a predetermined wireless base station number (for example, 0) attached to an empty codec circuit.

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

When the distribution circuit 212 of the concentrator 210 receives the signal frame 216 sent from the communication line 214, the communication line corresponding to the radio base station number 301 in the frame (here, 216-l) (here, 207). -L)
The signal frame is transmitted to the radio base station (here, 200-l) in the frame (here, 209-l) corresponding to the radio channel number 302 of. Further, the distribution circuit 212 discards the frame 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 205 of the radio base station 200-l receives the signal frame 209-l received from the communication line 207-l.
The radio channel number 3 set in the signal frame
02 to the address copying circuit 203-1 corresponding to No. 02. Address copy circuit 203-l that received the signal frame
Takes out the communication information 304 in the signal frame and sends it to the mobile terminal 227 through the wireless channel 201 through the wireless device 202-1. As described above, the mobile terminal 227 can receive the signal from the telephone 267.

The signal from the mobile terminal 227 is received by the wireless device 202-1 through the wireless channel 201-1, and is input to the address copying circuit 203-1. The address copying circuit 203-l decomposes the received signal into frames and sets them in the communication information 307 according to the signal format 305 from the radio base station to the mobile communication switching center shown in FIG. 2F, and is sent from the distribution circuit 205. The codec circuit 222-l of the signal frame 209-l is set to the codec number 30.
6 is set and 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 it to the multiplexing circuit 204.

The multiplexing circuit 204 is used for each address copying circuit 20.
The signal frames sent from 3-l to 203-n are sequentially multiplexed with the frames of the communication line 206-l and sent to the concentrator 210. Here, the signal from the address copying circuit 203-l is It will be described as being placed in the frame 209-1. Multiplexing circuit 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-l and transmits the signal of the frame 209-l to the communication line 213.
Mobile communication switching center 2 by inserting it into the signal frame 215-l of
Send to 17. If the codec number is a predetermined specific number (for example, 0), the frame is discarded.

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

In FIG. 1 used in the above description, the signal frames transmitted through the respective communication lines (206, 207, 213, 214) are properly time-slotted in order corresponding to the radio channel and the codec circuit. It is clear that this signal frame does not depend on the time slot position. Even if the signal frame is stored in a buffer at the time when the generation / assembly of the signal is finished and is sequentially sent to the communication line in the unit of the signal frame, it is the same. It is clear that this can be achieved. Further, at this time, when the codec circuit or the radio is not used, it is not necessary to send a dummy signal in which a specific number is set as the base station number / codec number.

As described above, according to the present invention, it is not necessary to fixedly correspond one-to-one with the wireless channels and the codec circuits through the communication lines. Therefore, only the required wireless channels and codec circuits are prepared. You can do it as you like.

[0025]

As described above, according to the present invention, it is not necessary to physically associate a communication channel or a codec circuit with a radio channel on a one-to-one basis, and resources such as the communication line and the codec circuit are allocated to each radio channel. Since the channels can be commonly used, it is possible to suppress an increase in the number of required resources even when providing a service in an area where the subscriber density is low, and to economically configure a mobile communication system.

FIG. 3 shows a calculation example of the number of codecs required in the configuration of FIG. 1 under the same accommodation conditions as the configuration example of the conventional system shown in FIG. 4B (example in the case of low subscriber density). When the method of the present invention is applied, any codec circuit can be used in common by each radio base station, and therefore it is sufficient to prepare only a sufficient number to satisfy the call loss rate with the total call volume of 50 Erl accommodated by the exchange. Since the codec circuit is commonly used by each radio base station, even if the call loss rate is set to a very low value of 0.1%, it will be 71 circuits when calculated from the Erlang B equation.

From the above, when the exchange accommodates a call volume of 50 Erl, the conventional system requires 100 circuits as compared with FIG. 4B, but the system to which the method of the present invention is applied requires 7 circuits as shown in FIG.
The number of required codec circuits can be greatly reduced since the number of circuits becomes one. Further, in the method of the present invention, the required number of codec circuits can be limited to the number of calls accommodated per concentrator even if the number of wireless base stations changes, so that it is less affected by the subscriber density, and compared to the conventional method. The mobile communication system can be economically constructed without being affected by the subscriber density.

[Brief description of 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 structure of the 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 a 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)

[Claims] 1. A communication method of a mobile communication system comprising a mobile communication switching station, a plurality of radio base stations, and a plurality of mobile terminals, wherein the mobile communication switching station converts a signal by a signal conversion device, and the conversion is performed. The converted signal is framed, and for each frame, the signal conversion device information that specifies the device used for the signal conversion, the wireless base station to which the frame is sent and the wireless base station to which the frame is to be transmitted. Radio line information that specifies each radio channel is added, and frames for the same radio base station are multiplexed and transmitted to the corresponding radio base stations. The signal transmitted to the terminal is added to the signal conversion device information 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.