JP3068369B2 - Wireless zone switching 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 radio zone switching system, and more particularly, to a radio base station which covers a plurality of radio zones, is connected to a mobile unit moving between radio zones by switching radio frequencies, and is connected to the radio base station. In a conventional mobile switching system that receives and updates a wireless zone, a switching center can reduce a load such as a radio frequency switching instruction.

[0002]

2. Description of the Related Art Conventionally, this type of mobile telephone exchange system starts with a mobile telephone exchange 300 which performs an exchange operation as shown in FIG.
04 to wireless zones 106 to 10 that are wirelessly connected
9 are configured. Each wireless base station is connected to a wired line 30.
8 to 311 connect the mobile telephone exchange 300 to the mobile telephone exchange 300 by wire. Now, when performing a wireless zone switching operation during a call of the mobile telephone subscriber terminal 105 moving from the wireless zone 108 to the wireless zone 107, the mobile telephone subscriber terminal 105 first captures the radio frequencies f4 and f5. Then, it is in a call state with a telephone subscriber existing in the other network 400 via the wired line 308 of the mobile telephone exchange 300. At this time, the wireless base station 304 constantly monitors the reception level from the mobile telephone subscriber terminal 105. Next, when the mobile telephone subscriber terminal 105 moves from the wireless zone 108 to the wireless zone 107, when the wireless base station 304 detects a decrease in the reception level from the telephone subscriber terminal 105, the mobile telephone switching center 300 On the other hand, it notifies that the reception level from mobile telephone subscriber terminal 105 has deteriorated. The mobile telephone exchange 300 is connected to the peripheral radio base station 30.
The mobile terminal 203 issues an instruction to monitor the reception level from the mobile telephone subscriber terminal 105, and the peripheral base station reports the monitoring result to the mobile telephone exchange 300. For example, when the radio base station 303 determines that the reception level from the mobile telephone subscriber terminal 105 is the highest, the mobile telephone switching center 300 transmits the radio frequency f to the mobile telephone subscriber terminal 105.
An instruction is issued to switch the wireless channels from the wireless channels f4 and f5 to the wireless frequencies f2 and f3, and the wired line 308 is switched to the wireless channel 309. According to the instruction, the mobile telephone subscriber terminal 105 changes the radio frequency f accompanying the shift to the radio zone 107 during a call.
Switching to 2 and f3 is executed. Other wireless zone 10
6, 109 for the radio base stations 301 and 302.
Monitor the reception level, report it to the exchange 300, and receive an instruction to switch the radio frequency based on the determination result of the exchange 300.

On the other hand, as another conventional example, as shown in, for example, Japanese Patent Application Laid-Open No. 2-222224, a fixed radio station and a mobile terminal in each zone of a small zone configuration receive a reception electric field level and zone registration information. There is a method of owning and distributing. That is, the own mobile terminal receives the measurement of the received electric field level from the surrounding radio base station, receives the information from the plurality of fixed radio stations, and displays the position indicating the location state of the other mobile terminal in each radio zone. A storage unit for storing a table of registration information in the CPU of the mobile terminal as management information. In this system, a mobile terminal selects a fixed wireless station in a wireless zone having a high received electric field and sends a location request signal to the fixed wireless station. Upon receiving the location registration information from the fixed wireless station, the location registration information is also registered in its own storage unit. The registration has a timer and the registration is held for a certain time. In this way, the mobile terminal performs position registration for communication setting under its own initiative, and the fixed wireless station passively performs only permission / denial of position registration. This information was transmitted to the mobile switching center.

[0004]

In the above-described conventional mobile telephone switching system, each time a mobile telephone subscriber terminal moves to another wireless zone, the mobile telephone exchange places a frequency of a wire line and a radio channel. Since it is necessary to perform the switching control, when the mobile telephone subscriber terminal is moving between the wireless zones at a high speed, the load on the above processing of the mobile telephone exchange becomes enormous. There is a disadvantage that.

In another conventional example, since the mobile terminal measures the reception electric field level of the fixed radio station, the burden on the mobile telephone exchange can be reduced. Since it is necessary to send and receive location registration information between them and confirm whether or not the registration is accepted, there is a disadvantage that when the number of fixed wireless stations increases, the processing of the storage unit and CPU of the mobile terminal becomes complicated.

[0006]

According to the present invention, there is provided a wireless zone switching system comprising: a mobile telephone exchange which performs a switching connection;
Consists of a plurality of wireless stations forming a wireless zone
Radio of mobile terminal moving in mobile telephone switching system
It is a zone switching method and has the following configuration.
Sign. (1) Directly connected to the mobile telephone exchange,
To transmit and receive signals at the radio frequency used in the
A radio base station equipped with a line communication antenna; and (2) transmission of a signal at a radio frequency used by an adjacent radio station.
Directional antenna for reception and use in own radio zone
A wireless communication antenna that transmits and receives signals at radio frequencies
A radio relay station comprising: (3) the radio base station and at least one radio
The wireless relay station, which is composed of relay stations and is adjacent to the wireless base station,
Communicates with a wireless base station using a directional antenna and
If there is a line relay station, the other wireless relay stations are wireless base stations.
And the directivity relay station with
While forming a cascaded communication path using antennas
A radio zone, (4) near the radio zone each radio frequency information and peripheral
Whether each of the wireless zones belongs to the middle wireless zone
When the information indicating whether or not to switch the wireless zone is stored,
The destination wireless zone is the same as the source wireless zone
If it belongs to the middle radio zone, switch only the radio frequency
Mobile terminal.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram showing one embodiment of a wireless zone switching system according to the present invention, and FIG. 2 is an explanatory diagram of a wireless zone and a wireless frequency in the embodiment of FIG.

In the mobile telephone switching system shown in FIG. 1, the wireless zone includes the wireless zones 106, 107 and 108, and a wireless base station area (hereinafter referred to as a middle wireless zone) 110.
, And the wireless base station 101 is arranged in the middle wireless zone 110. This radio base station 101 is connected to the small zones 107, 1
In 08, the radio relay stations 103 and 104 are respectively arranged as subordinates. The radio transmission between the radio relay stations is performed by a directional antenna 117, separately from the radio communication antennas 113, 114 of the mobile telephone subscriber terminal (hereinafter, referred to as a mobile) 105.
118. In the middle wireless zone 111, only the wireless base station 102 is arranged. Wireless base stations 101 and 102
Are connected to a mobile telephone exchange (hereinafter, referred to as exchange) 100 by wired lines 310 and 311. The radio frequencies communicated with the mobile unit and the radio relay stations 103 and 104 in the small zones 107 and 108 are f2, f3 and f4, respectively.
f5. Also, the wireless base station 101 in the small zone 106
Are the radio frequencies f0 and f1, and the radio base station 102 in the middle radio zone 111 uses the radio frequencies f6 and f7. The designation of the medium radio zone and the small zone radio frequency and the adjacent peripheral zone are as shown in FIG.
Reference numeral 05 stores all the information of FIG. 2 in its own storage unit.

First, the operation of the entire mobile communication system will be described. When the moving object 105 has the frequency f4 of the small zone 108,
f5 is captured, and the wired line 123 is used for the wireless channel CHO in the downstream frame 119 and the upstream frame 120 from the exchange 100 allocated to the wireless base station area 110.
And 310 are in communication with telephone subscribers present on other networks. At this time, the CHO information of the downlink frame 119 is transmitted to the radio base station 101 by a time division multiplexing (TDM) communication method.
Is relayed to the directional antenna 117 of the wireless relay station 103 at the frequency f0 via the omnidirectional antenna 112, and is relayed to the directional antenna 118 of the wireless relay station 104 at the frequency f2 via the omnidirectional antenna 113. Further, the signal is relayed to the omnidirectional antenna 116 of the mobile unit 105 at the frequency f4 via the omnidirectional antenna 114. Conversely, the CHO information of the upstream frame 120 is transmitted by the time division multiple access (T
According to the DMA) communication method, the signal is relayed to the omnidirectional antenna 114 of the radio relay station 104 at the frequency f5 via the omnidirectional antenna 116 of the mobile body 105, and the directional antenna 118
Is transmitted to the omni-directional antenna 113 of the wireless relay station 103 at the frequency f3 via the directional antenna 117, and further transmitted to the omni-directional antenna 1 of the wireless base station 101 at the frequency f1 via the directional antenna 117.
12 is relayed. On the other hand, the wired line 1 in the exchange 100
The information of the downstream frame 121 assigned to the middle wireless zone 111 corresponding to 24 and 311 is transmitted to the wireless zone 1 at the frequency f6 via the omnidirectional antenna 115 of the wireless base station 102 by the time division multiplexing (TDM) communication method.
09, and the information of the upstream frame 122 is:
When a mobile object exists in the middle wireless zone 111, the signal is received by the omnidirectional antenna 115 of the wireless base station 102 at the frequency f7 and relayed by the wired line 311, also by the time division multiple access (TDMA) communication method.

Here, the operation of the moving object of the present invention will be described. The mobile unit 105 constantly monitors the reception electric field level of the currently acquired radio frequency f4 during a call. At this time, when the moving body 105 moves from the small zone 108 to the small zone 107, the reception level of the radio frequency f4 of the moving body 105 decreases. The mobile unit 105 is connected to the radio frequency f currently being acquired.
When it is detected that the reception level of No. 4 has dropped below a certain value, the reception of the downstream radio frequencies f2 and f6 used in the surrounding radio zones based on the pre-stored information of the frequency usage form shown in FIG. Start the operation to measure the level. Then, when the radio frequency f2 having the highest reception level is identified, the radio frequency f2 having the highest reception level is identified based on the information of the frequency usage pattern shown in FIG. It is determined whether or not the radio frequency f4 being captured exists in the same radio zone as the radio frequency f4. As a result, when it is determined that the radio frequency f2 and the radio frequency f4 are present in the same medium radio zone 110, the mobile unit 105 independently transmits the downlink frame 1
19 and the radio frequency f corresponding to the small zone 107 while maintaining the same radio channel CHO in the upstream frame 120.
2 and f3 are captured and the call is continued. As a result, the frequency switching from the small zone 108 to the small zone 107 has been performed, and the communication between the mobile unit 105 and the telephone subscribers existing in the other networks is performed according to the wireless channel number and the wired This is done by changing only the radio frequency without changing the line. When the moving body 105 moves from the small zone 107 to the middle wireless zone 109, the moving body 1
At 05, the reception level of the currently acquired radio frequency f2 decreases. The mobile unit 105 is connected to the radio frequency f2 currently being acquired.
When it is detected that the reception level has dropped below a certain value, based on the pre-stored information on the frequency usage pattern shown in FIG. 2, the downstream radio frequencies f0, f4 and f6 used for the surrounding radio zones are determined. The operation for measuring the reception level is started. Then, when the radio frequency f6 having the highest reception level is identified, it is stored again in FIG.
It is determined whether the identified radio frequency f6 having the highest reception level exists in the same radio base station area as the currently acquired radio frequency f2 based on the information on the frequency usage pattern shown in FIG. As a result, when it is determined that the radio frequency f6 and the radio frequency f2 do not exist in the same radio base station area and have shifted to another medium radio zone, the mobile unit 105
Is given to the exchange 100 at the radio frequency f3 currently being acquired,
A request to switch the radio channel to the radio frequency f6 is issued. Upon receiving the request, the switching center 100 issues an instruction to the mobile unit 105 to switch to a free wireless channel CHO in the downstream frame 121 and the upstream frame 122 which are set independently of the frames 119 and 120 described above. An operation of switching the line from 123 to 124 and 311 is executed. When the mobile unit 105 receives a radio channel switching instruction from the exchange 100 via the currently acquired radio frequency f2, the mobile unit 105 changes the radio frequencies to be captured to f6 and f7, and the instructed downlink frame 121 and uplink frame 122. Radio channel in the upstream and downstream frames 12
The call is continued on channel CHO of 1,122. As a result, the wireless zone switching from the middle wireless zone 110 to the middle wireless zone 111 has been performed. Will be changed.

[0012]

As described above, according to the present invention, a plurality of small radio zones are put together to form one radio base station area (medium radio zone), and one radio base station is arranged in the middle radio zone. Further, means for providing a radio relay station having a different radio frequency separately connected to the radio base station by radio with a directional antenna, and the mobile itself monitors the reception electric field of a different radio frequency signal in the middle radio zone. By providing means for selecting a radio frequency having a strong reception electric field, it is possible to reduce the number of radio base stations which are controlled and instructed by the exchange. The communication system from the exchange to the mobile is TDM.
By using the TDMA system as the communication system in the reverse direction, the exchange can specify the time-division channel, perform the switching operation, and only select the wired route with the radio base station, thereby reducing the load on the exchange. There is.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a wireless zone and a wireless frequency in the embodiment of FIG. 1;

FIG. 3 is a system configuration diagram of a conventional example.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 Mobile telephone exchange (exchange station) 101, 102 Radio base station 103, 104 Radio relay station 105 Mobile telephone subscriber terminal 106, 107, 108 Radio zone (small zone) 110, 111 Radio base station area (medium radio Zone) 112, 113, 114, 115, 116 Non-directional antenna 117, 118 Directional antenna 119, 121 Down frame 120, 122 Up frame 123, 124, 310, 311 Wired line

Claims (1)

(57) [Claims] (1)The mobile telephone exchange that performs the switching connection and it
Each consisting of a plurality of radio stations forming a radio zone
Of mobile terminals moving within the mobile telephone switching systemNothing
In the line zone switching method,Directly connected with the mobile switching center, own radio zone
Communication that transmits and receives signals at the radio frequency used in
A radio base station with an antenna, Transmit and receive signals at the radio frequencies used by adjacent radio stations
Directional antennas and the radio frequency
And a wireless communication antenna for transmitting and receiving signals at wave numbers.
Radio relay station, The radio base station and at least one radio relay station
And the radio relay station adjacent to the radio base station is
It communicates with the radio base station using a directional antenna,
If there are a number of said radio relay stations, the other of said radio relay stations
The station is located in front of the preceding station where a communication path is formed with the radio base station.
Cascade connection using the radio relay station and the directional antenna
A medium wireless zone forming a continuous communication path, Radio frequency information of each peripheral wireless zone and peripheral wireless zone
Indicate whether each zone belongs to the medium radio zone.
When switching wireless zones, the information
Wireless zone is the same as the switch-source wireless zone.
Mobile stations that switch only radio frequencies
Have a terminal A wireless zone switching method.