JP2880969B2 - Packet signal selection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile switching center for realizing macro diversity in a mobile communication system for transmitting a packet signal between a mobile switching center and a radio base station.

[0002]

2. Description of the Related Art In a conventional mobile communication system such as a mobile phone or a mobile phone, a small zone system is adopted in which the entire service area of the mobile communication system is covered by a plurality of wireless zones. Here, the wireless zone refers to a range in which each wireless base station performs communication using a wireless channel with a mobile device mounted on an automobile or the like. One wireless base station is arranged in one wireless zone, and a plurality of mobile stations move freely in each wireless zone. In addition, each wireless base station can use a plurality of wireless channels, and determines a wireless channel to be used based on a radio wave propagation environment between the mobile station and a mobile station that performs communication. In addition, when the radio wave propagation environment of the radio channel used during communication deteriorates, the mobile station shifts to another radio channel. This is called "channel switching during communication" (handover). A mobile switching center is a device that controls the radio base station and performs circuit switching with a fixed telephone network.

[0003] Digital mobile communication systems currently under study (Nakajima et al., "Digital Mobile Communication System Concept", Proceedings of the 1991 Spring Conference of the Institute of Electronics, Information and Communication Engineers, Spring B-317 and ishino et al., "Mobile communica
tion switching system forvoice / nonvoice services
”, IEEE GLOBECOM'91, pp.1485-148
In 9), as shown in FIG. 6, the mobile switching center 1 is composed of a mobile switching center 3 accommodating a non-voice / ISDN adapter 2, voice processing devices 4 and 5, and a three-way connection trunk 6, and a radio base station 10 Is composed of modems 11 and 12, a control device 13, a common amplifying device 14, and an antenna 15. The audio processing devices 4 and 5 are signal compression devices composed of a CODEC or the like.

In the line between the mobile switching center 1 and the radio base station 10, a 64 kbps line is duplicated to improve the reliability of the control signal transmission line 18, and a voice signal transmission line 19 is provided.
For the audio processing devices 4 and 5 on the 64 kbps transmission line
The output signal of 11.2 kbps is multiplexed by the synchronization terminal station 16 on the mobile switching center 1 side by three-channel time division multiplexing, and is divided by the synchronization terminal station 17 on the radio base station 10 side to reduce the line cost. Is being planned. Also,
By using the three-way connection trunk 6 to connect the old wireless base station, the new wireless base station, and the public network in advance before switching the wireless line at the time of handover, an instantaneous interruption is attempted.

In the conventional mobile communication system shown in FIG. 6, it is difficult to apply different bit rates because the degree of multiplexing on the transmission path must be changed depending on the bit rates of the audio processors 4 and 5. Further, there is a disadvantage that a special three-way connection trunk 6 is required to perform a three-way connection at the time of handover. To compensate for these shortcomings, the transmission between the mobile switching center and the radio base station requires:
It has been proposed to use packet signals (Japanese Patent Application No. Hei 4
-181405, 4-183269). By transmitting packets between the mobile switching center and the radio base station, the number of packet signals transmitted per unit time can be changed to support various bit rates. It is only necessary to change the destination address of the created packet signal, and no special device such as the three-way connection trunk 6 is required.

[0006] Also, a radio signal from a mobile station is received by a plurality of radio base stations, and a macro diversity that aims at improving the signal quality is used. Studies are also underway ("An overview of the Application of Code Di"
vision Multiple Access to Digital Cellul-ar
Systems and Personal Communication Network
s ", QUALCOMM, Ink., January 11, 1991). In order to realize macro diversity, the mobile switching center 50 is configured as shown in FIG.
As shown in FIG. 7, after exchanging signals from a plurality of radio base stations using the digital exchange 52, the signals are output as one signal in the diversity synthesizer 55,
4 and is connected to a public network via a digital exchange 51, or turned back at the digital exchange 51 and connected to a mobile unit in a mobile communication network via a voice processing device 54 and a digital exchange 52. ing.

[0007]

However, in the conventional mobile switching center of FIG. 7, since the diversity synthesizers 55 are directly attached to the voice processing devices 54, the number of the diversity synthesizers 55 equal to the number of the voice processing devices 54 are increased. Required,
In the case of communication between mobile devices, the signal passes through the audio processing device 54 twice and becomes a deterioration factor in the case of an audio signal. Since the diversity synthesizer 55 inputs signals from the digital exchange 52 through a plurality of input terminals, the digital synthesizer 52
However, there is a problem that the management of the input destination of the signal from the wireless base station becomes complicated.

[0008]

In order to solve the above-mentioned problems, the present invention provides the following means.

That is, the packet signal selecting apparatus of the present invention
Is composed of a plurality of mobile stations, a plurality of radio base stations for communicating by radio channels between the mobile stations in its own radio zone, and a mobile switching center for controlling the plurality of radio base stations. Between the mobile switching center and the radio base station, provided in the mobile switching center in a mobile communication system that transmits signals in the form of packet signals, the same destination address respectively coming from a plurality of communication paths a selection to Rupa packet signal selecting apparatus one of the plurality of packet signals, via a packet switch during handover with
Te, only input terminals and a plurality of signal storage unit for storing the input packet signals, two or more identical destinations are entered to the input terminal for receiving a plurality of packet signals having the same destination address Switching means for distributing and storing a packet signal having an address to each of the signal storage units different from each other, and a packet signal connected to all of the signal storage units and storing the packet signal in each of the signal storage units. by comparing some fraction of,
And a determiner for selecting one packet signal and outputting the selected one packet signal.

[0010]

According to the first aspect of the present invention, the modulation and demodulation device of a radio base station is used as in a digital car telephone system in Japan ("Digital Car Phone System", RCR STD-27, Radio System Development Center). Since the period of the generated signal is as large as 20 msec and packet signals from the same modem are not continuously input to the packet signal selector, the radio base station determines the signal-to-noise ratio and the signal quality. Is added to the packet signal selection device from only one input terminal, and the packet information stored in the signal storage unit is compared and selected by using the determination information. Is output. For this reason, even when signals from the same mobile station are simultaneously received by a plurality of radio base stations and transmitted to the mobile switching center, only one destination address is required for packet signals from a plurality of communication paths, and Address management is simplified.

In the first mobile switching center according to the present invention, a packet switching device is arranged between a communication signal processing device such as a voice processing device and a fax signal processing device and the packet signal selecting device, so that a communication signal processing device is provided. And the packet signal selection device can be freely combined.
Since the packet signal selection device may not be used,
The number of packet signal selection devices can be smaller than the number of communication signal processing devices. Further, by exchanging packet signals in the packet switch, even in the case of communication of a mobile organization, it is possible to prevent the signal quality from being deteriorated due to passing through a communication signal processing device and to obtain a diversity effect. .

In a second mobile switching center according to the present invention, a packet switch disposed between a communication signal processing device and a packet signal processing device and a packet switch serving as an interface with a radio base station are constituted by one packet switch. By realizing it, the configuration of the mobile switching center can be simplified.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing a first embodiment of the packet signal selecting apparatus according to the present invention. In the figure, 100 is a packet signal selection device, 10
Reference numerals 1 and 102 indicate a signal storage unit, 103 indicates an input terminal, 104 indicates a switching device, 105 indicates a determiner, and 106 indicates an output terminal. FIG. 2 is a diagram illustrating an example of a signal configuration of a packet signal transmitted between the wireless base station and the mobile switching center.

In the initial condition, it is assumed that the switching device 104 is connected to the signal storage unit 101. At the time of reception, the signal from the mobile device is packetized in the radio base station with the signal-to-noise ratio added as the determination information, as shown in FIG. Note that signal quality can be used for the determination information. The packet signal input from the input terminal 103 passes through the switching device 104 to the signal storage unit 101
Is stored. Thereafter, the switching device 104 switches the packet signal input destination to the signal storage unit 102. Judge 1
Reference numeral 05 compares the determination information in the packet signals stored in the signal storage units 101 and 102 at regular intervals. Assuming that the packet signal stored in the signal storage unit 101 is selected based on the determination information, the determinator 105 outputs the packet signal to the output terminal 106 and outputs the packet signal to the signal storage unit 10.
The packet signals stored in 1 and 102 are deleted.

FIG. 3 is a block diagram showing a second embodiment of the packet signal selecting apparatus according to the present invention. In the figure, 110 is a packet signal selection device, 111, 112,
Reference numeral 113 denotes a signal storage unit having a shift register function, 10
3 is an input terminal, 105 is a decision unit, and 106 is an output terminal.

The packet signal input from the input terminal 103 is first stored in the signal storage unit 111. When the next packet signal is input, the information of the packet signal stored in the signal storage unit 111 is shifted to the signal storage unit 112, and the newly input packet signal is stored in the signal storage unit 111. . The determiner 115 compares the determination information in the packet signals stored in the signal storage units 111, 112 and 113 at regular intervals. Assuming that the packet signal stored in the signal storage unit 111 is selected based on the determination information, the determinator 105 outputs the packet signal to the output terminal 106 and simultaneously outputs the packet signal to the signal storage units 111 and 11.
2 and 113 are deleted.
The signal-to-noise ratio described later is used as the determination information.

FIG. 4 is a block diagram showing an embodiment of the first mobile switching center related to the present invention. In the figure, 200
Is a mobile switching center, 201 is a public network interface between the public network and the mobile communication network, 202 and 203 are communication signal processing devices,
204 is a packet signal selection device, 205 and 206 are packet switches, 210 and 220 are radio base stations, and 230 is a mobile device. Incidentally, the packet signal selection device 204 may be either a packet signal selection device realized by the invention of claim 1 or a packet signal selection device having a plurality of input terminals. The communication signal processing devices 202 and 203
This is a device corresponding to the audio processing devices 4 and 5 and compressing a signal. The voice processing devices 4 and 5 handle only voice signals, while the communication signal processing devices 202 and 203 handle not only voice signals but also FAX signals and data.

It is assumed that the signal transmitted from mobile station 230 is received by radio base stations 210 and 220. Each of the radio base stations 210 and 220 adds a signal-to-noise ratio at the time of reception to form a packet signal and transmits the packet signal to the mobile switching center 200.
Since signals from the same mobile station are simultaneously received by a plurality of radio base stations, each packet signal is input to the packet signal selection device 204 via the packet switch 206. The packet signal selector 204 compares the signal-to-noise ratios of the two received packet signals, and outputs a packet signal having a higher signal-to-noise ratio to the packet switch 205.
Output to When the communication partner exists on the public network side, the packet signal passed to the packet switch 205 is decoded by the communication signal processing device 202 and sent to the public network via the public network interface 201. When the communication partner is located in the same mobile communication network, the packet signal is looped back by the packet switch 205 and transmitted to the communication partner. Thereby, at the time of communication between mobile units in the same mobile network, communication without passing through the communication signal processing device becomes possible, and deterioration of signal quality due to passing through the communication signal processing device twice can be prevented. On the other hand, mobile device 2
Assuming that the signal transmitted from the base station 30 is received only by the radio base station 210, the packet signal transmitted to the packet switch 206 must be transmitted through the packet signal selecting device 204 even if the communication partner exists on the public network side. Without being passed to the packet switch 205 and the communication signal processor 202
(Or 203), via the public network interface 201,
It will be sent to the public network. Therefore, an aggregation effect that the number of the packet signal selection devices 204 needs to be smaller than the number of the communication signal processing devices appears.

FIG. 5 is a block diagram showing an embodiment of the second mobile switching center relating to the present invention. In the figure, 300
Denotes a mobile switching center, 201 denotes an interface between a public network and a mobile communication network, 202 and 203 denote communication signal processors, 204
Is a packet signal selection device, 305 is a packet switch, 2
Reference numerals 10 and 220 are radio base stations, and 230 is a mobile unit.
Incidentally, the packet signal selection device 204 may be either a packet signal selection device realized by the invention of claim 1 or a packet signal selection device having a plurality of input terminals.

It is assumed that a signal transmitted from mobile station 230 is received by radio base stations 210 and 220. Each of the radio base stations 210 and 220 adds a signal-to-noise ratio at the time of reception to make a packet signal and transmits the packet signal to the mobile communication control station 300. Each packet signal is input to the packet signal selection device 204 via the packet switch 305 because signals from the same mobile unit are received by a plurality of radio base stations at the same time. The packet signal selector 204 compares the signal-to-noise ratios of the two received packet signals, and outputs a packet signal having a higher signal-to-noise ratio to the packet switch 305.
Output to When the communication partner exists on the public network side, the packet signal passed to the packet switch 305 is decoded by the communication signal processing device 202 and sent to the public network via the public network interface 201. When the communication partner is located in the same mobile communication network, the packet signal is looped back by the packet switch 305 and transmitted to the communication partner. Thereby, at the time of communication between mobile units in the same mobile network, communication without passing through the communication signal processing device is possible, and deterioration of signal quality due to passing through the communication signal processing device twice can be prevented. On the other hand, mobile device 2
Assuming that the signal transmitted from the wireless base station 210 is received only by the radio base station 210, the packet signal transmitted to the packet switch 305 can be transmitted without passing through the packet signal selecting device 204 even when the communication partner exists on the public network side. The data is sent to the public network via the communication signal processing device 202 (or 203) and the public network interface 301. Therefore, an aggregation effect that the number of the packet signal selection devices 204 needs to be smaller than the number of the communication signal processing devices appears. Also,
By realizing a packet switch disposed between the communication signal processing devices 202 and 203 and the packet signal selection device 204 and a packet switch serving as an interface with the radio base stations 210 and 220 with one packet switch, the mobile station can move. The configuration of the exchange can be made simpler than in the embodiment of FIG.

[0021]

As described above in detail with reference to the embodiments, the following effects can be obtained by the present invention.

By inputting a packet signal from only one input terminal using the packet signal selecting device of the first aspect of the present invention, management of the destination address of the packet signal necessary for inputting to the packet signal selecting device is performed. This is easier than a packet signal selection device having a plurality of input terminals.

In the mobile switching center according to the first or second aspect of the present invention, even in the case of communication between mobile stations located in the same mobile communication network, signal exchange is performed after selection of a packet signal by the packet signal selection device. , A diversity effect can be obtained without using a communication signal processing device. In addition, since the packet signal selection devices are not always used during communication, the number of packet signal selection devices can be significantly reduced from the number of communication signal processing devices due to the aggregation effect.

In a second mobile switching center relating to the present invention,
The function of the packet switch disposed between the communication signal processing device and the packet signal selection device and the function of the packet switch serving as the interface with the radio base station is shared by a single packet switch, so that the configuration of the mobile switching center can be improved. It can be concise.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a packet signal selection device according to the present invention of claim 1;

FIG. 2 is a diagram illustrating an example of a signal configuration of a packet signal transmitted between a radio base station and a mobile communication control station.

FIG. 3 is a configuration diagram showing a second embodiment of the packet signal selection device according to the present invention;

FIG. 4 is a configuration diagram showing an embodiment of a first mobile switching center related to the present invention.

FIG. 5 is a configuration diagram showing an embodiment of a second mobile switching center related to the present invention.

FIG. 6 is a block diagram showing an example of a conventional mobile switching center communication system using a mobile switching center.

FIG. 7 is a block diagram illustrating an example of a mobile switching center when achieving macro diversity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mobile switching center 2 Non-voice / ISDN adapter 3 Mobile communication switching system 4, 5 Voice processing device 6 Three-way connection trunk 10 Radio base station 11, 12 Modulation / demodulation device 13 Control device 14 Common amplifier 15 Antenna 16, 17 Synchronization terminal 18, Reference Signs List 19 transmission path 50 mobile switching center 51, 52 digital switch 53 control unit 54 voice processing unit 55 diversity synthesizer 100 packet signal selection unit 101, 102 signal storage unit 103 input terminal 104 switching unit 105 decision unit 106 output terminal 110 packet signal selection Device 111, 112, 113 Signal storage unit 200 Mobile switching center 201 Public network interface between public network and mobile communication network 202, 203 Communication signal processing device 204 Packet signal selection device 205, 206 Packet switch 210, 220 Wireless base station 30 mobile device 300 mobile switching center 305 packet switch

Continuation of the front page (56) References JP-A-3-179849 (JP, A) JP-A-62-169005 (JP, A) JP-A-46-2753 (JP, A) Jpn. , U) “New Radio Technology III Wireless Communication 1”, New Radio Technology Editing Committee, published by Lattice (55.1.25, 1980), p. 26-27 Electronic Information and Communication Handbook (3.3.30, 1988) Vol. 2394−2402

Claims (1)

(57) [Claims] 1. A plurality of radio base stations for communicating over a radio channel between a plurality of mobile stations and the mobile stations in its own radio zone, and a mobile switching center for supervising the plurality of radio base stations. The mobile switching center and the radio base station are provided in the mobile switching center in a mobile communication system that transmits a signal in the form of a packet signal, the same coming from a plurality of communication paths respectively Have destination address
One and a plurality of selection to Rupa packet signal selecting apparatus of one of the packet signals, and the only input terminal for inputting via a packet switch at the time of handover, a plurality of packet signals having the same destination address, a plurality of signal storage unit for storing the input packet signals, two or more identical to the input to the input terminal
Switching means for distributing and storing a packet signal having a destination address in each of the different signal storage units, and a switching unit connected to all of the signal storage units and storing the packet signal in each of the signal storage units; by comparing some fraction of the signal, selects one of the packet signals, a packet signal selecting apparatus characterized by being composed of a determiner for outputting said one packet signal selected.