JPH0723444A - Wireless zone switching method - Google Patents

Abstract

PURPOSE:To relieve the load with respect to radio zone changeover processing between a radio base station and a mobile telephone exchange station by forming a radio base station area covering the radio base station with plural small zones in which a radio relay station is arranged. CONSTITUTION:The mobile telephone exchange system provided with a mobile object selecting at least a radio frequency when the mobile object moves between radio zones covered by plural radio base stations and with a mobile object telephone exchange station in wired connection of communication information of the mobile object via a radio base station and making exchange connection with other telephone exchange, is provided with radio relay stations 103, 104 arranged to small zones 107, 108 being divisions of radio zones 110, 111 covered by the radio base stations 101, 102 and directivity antennas 117, 118 in radio connection to the radio base stations under the control of the radio relay station to reduce number of radio base stations in wired-connection to the mobile telephone exchange 100.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless zone switching system, and in particular, a wireless base station covering each of a plurality of wireless zones is connected to a mobile unit moving between the wireless zones by switching the wireless frequency and the like. The present invention relates to a wireless zone switching system in which a switching center can reduce a load such as a wireless frequency switching instruction in a conventional mobile switching system that receives and updates a switching center designation.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a mobile telephone exchange system of this type has a mobile telephone exchange station 300, which controls exchange operations, as a starting point, and respective radio base stations 301 to 301.
Wireless zones 106 to 10 which are wirelessly connected in correspondence with 04.
9 are configured. In addition, each wireless base station has a wired line 30
8 to 311 connect to the mobile telephone switching center 300 by wire. When performing the operation of switching the wireless zone when 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 another network 400 via the wired line 308 of the mobile telephone switching center 300. At this time, the radio 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 radio zone 108 to the radio zone 107, when the radio base station 304 detects a decrease in the reception level from the telephone subscriber terminal 105, the mobile telephone switching center 300 is notified. It notifies that the reception level from the mobile telephone subscriber terminal 105 has deteriorated. The mobile telephone switching center 300 is the peripheral wireless base station 30.
2, 303 is instructed to monitor the reception level from the mobile telephone subscriber terminal 105, and the peripheral wireless base station reports the monitoring result to the mobile telephone switching center 300. For example, when the mobile telephone switching center 300 determines that the radio base station 303 has the highest reception level from the mobile telephone subscriber terminal 105, the radio frequency f is transmitted to the mobile telephone subscriber terminal 105.
A wireless channel switching instruction from 4 and f5 to wireless frequencies f2 and f3 is issued and the wired line 308 is switched to 309. The mobile telephone subscriber terminal 105 is instructed by the mobile telephone subscriber terminal 105 to use the radio frequency f associated with the shift to the radio zone 107 during a call.
Switch to 2 and f3. Other wireless zone 10
Similarly, for the radio base stations 301 and 302,
Monitored the reception level, reported it to the exchange 300, and received a radio frequency switching instruction according to the determination result of the exchange 300.

On the other hand, as another conventional example, as shown in, for example, Japanese Patent Laid-Open No. 222222/1990, a fixed radio station and a mobile terminal in each zone of a small zone configuration receive a received electric field level and zone position registration information. There is a method of distributing and owning. That is, its own mobile terminal measures the reception electric field level from the surrounding wireless base stations and receives information from a plurality of these fixed wireless stations to determine the position of the other mobile terminals in each wireless zone. A storage unit that stores a table of registration information in the CPU of its own mobile terminal as management information is provided. In this system, the 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. When the location registration information is received from the fixed wireless station, it 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 takes the initiative in registering the location for communication setting, and the fixed wireless station passively performs only the approval or disapproval of the location registration. Also, this information was transmitted to the mobile switching center.

[0004]

In the conventional mobile telephone switching system described above, each time the mobile telephone subscriber terminal moves to another wireless zone, the frequency of the wired line and the frequency of the wireless channel are changed in the mobile telephone switching center. Since switching control needs to be performed, when the mobile telephone subscriber terminal moves between wireless zones at a high speed, the load of the mobile telephone switching center on the above-mentioned processing becomes enormous. There is a drawback that.

Further, in another conventional example, since the mobile terminal measures the received electric field level of the fixed radio station, the load on the mobile telephone switching center is reduced, but with the fixed radio station for each small zone. Since it is necessary to send and receive the position registration information between them to confirm the approval or disapproval of the registration, there is a disadvantage that the processing of the storage unit and the CPU of the mobile terminal becomes complicated when the number of fixed wireless stations increases.

[0006]

According to the wireless zone switching method of the present invention, a mobile telephone subscriber terminal (hereinafter referred to as a mobile body) that switches at least a radio frequency when moving between radio zones covered by a plurality of radio base stations. ), And communication information of the mobile unit through the wireless base station by wire connection, and a mobile telephone switching system including a mobile telephone switching center for switching connection with another telephone switching network, in a wireless zone switching method in a mobile telephone switching system, The wireless zone covered by the wireless base station is divided into a plurality of small zones, the wireless relay stations being subordinate to the wireless base stations arranged in each of the small zones, and the wireless relay station wirelessly connecting to the wireless base station. And the number of the wireless base stations wiredly connected to the mobile telephone switching center is reduced.

[0007]

The present invention will be described below with reference to the drawings.

FIG. 1 is a system configuration diagram showing an embodiment of a wireless zone switching system of 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 exchange system shown in FIG. 1, the wireless zone includes wireless zones 106, 107 and 108, and a wireless base station area (hereinafter referred to as middle wireless zone) 110.
The wireless base station 101 is arranged in the middle wireless zone 110. This wireless base station 101 is a small zone 107,1
08, the wireless relay stations 103 and 104 are arranged as subordinates, respectively. The wireless transmission between the wireless relay stations includes a directional antenna 117, separately from the wireless communication antennas 113 and 114 of the mobile telephone subscriber terminal (hereinafter referred to as mobile) 105.
118. Only the wireless base station 102 is placed in the middle wireless zone 111. Radio base stations 101 and 102
Is connected to a mobile telephone exchange station (hereinafter referred to as exchange station) 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.
It is f5. In addition, the wireless base station 101 in the small zone 106
Are radio frequencies f0 and f1, and the radio base station 102 in the middle radio zone 111 uses radio frequencies f6 and f7. The middle radio zone and the small zone radio frequencies are designated and the adjacent peripheral zones are as shown in FIG.
Reference numeral 05 stores all the information shown in FIG. 2 in its own storage unit.

First, the operation of the entire mobile communication system will be described. When the mobile unit 105 has the frequency f4 of the small zone 108,
Wired line 123 by radio channel CHO in downlink frame 119 and uplink frame 120 from switching center 100 that has captured f5 and is assigned to radio base station area 110
Through 310 and 310, it is in a call state with a telephone subscriber existing in another network. At this time, the CHO information of the downlink frame 119 is obtained by the time division multiplexing (TDM) communication method.
The signal is relayed to the directional antenna 117 of the wireless relay station 103 at the frequency f0 via the omnidirectional antenna 112 and to the directional antenna 118 of the wireless relay station 104 at the frequency f2 via the omnidirectional antenna 113. Further, it is relayed to the omnidirectional antenna 116 of the mobile body 105 at the frequency f4 via the omnidirectional antenna 114, and conversely, the CHO information of the upstream frame 120 is time-division multiple access (T).
The directional antenna 118 is relayed to the omnidirectional antenna 114 of the wireless relay station 104 at the frequency f5 via the omnidirectional antenna 116 of the mobile body 105 by the DMA) communication method.
To the omnidirectional antenna 113 of the radio relay station 103 at a frequency f3 via the directional antenna 117, and the omnidirectional antenna 1 of the radio base station 101 at a frequency f1 via the directional antenna 117.
It will be relayed to 12. On the other hand, the wired line 1 in the exchange 100
The information of the downlink frame 121 allocated to the medium wireless zone 111 corresponding to 24 and 311 is the same as that of 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 body is present in the middle wireless zone 111, it is also received by the omnidirectional antenna 115 of the wireless base station 102 at the frequency f7 and relayed by the wired line 311 by the time division multiple access (TDMA) communication method.

The operation of the moving body of the present invention will now be described. The mobile body 105 constantly monitors the reception electric field level of the radio frequency f4 which is currently being captured during a call. At this time, when the mobile body 105 moves from the small zone 108 to the small zone 107, the reception level of the radio frequency f4 of the mobile body 105 decreases. The mobile unit 105 uses the radio frequency f currently being acquired.
When it is detected that the reception level of 4 has fallen below a certain value, reception of the downlink radio frequencies f2 and f6 used in the peripheral radio zone based on the frequency usage pattern information stored in advance in FIG. Start the operation of measuring the level. Then, when the radio frequency f2 having the highest reception level is identified, the identified radio frequency f2 having the highest reception level is identified based on the previously stored information on the frequency usage pattern shown in FIG. It is determined whether or not the radio frequency f4 being captured is in the same radio zone. As a result, when it is determined that the radio frequency f2 and the radio frequency f4 exist in the same middle radio zone 110, the mobile unit 105 independently determines the downlink frame 1
19 and the radio frequency f corresponding to the small zone 107 with 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 has been switched from the small zone 108 to the small zone 107, and the telephone call between the mobile unit 105 and the telephone subscriber existing in the other network is performed by the wireless channel number and the wired line designated by the exchange 100. Only the radio frequency will be changed without changing the line. When the mobile unit 105 moves from the small zone 107 to the middle wireless zone 109, the mobile unit 1
At 05, the reception level of the radio frequency f2 currently being acquired is reduced. The mobile unit 105 uses the radio frequency f2 currently being acquired.
When it is detected that the reception level has fallen below a certain value, the downlink radio frequencies f0, f4, and f6 used in the surrounding radio zones are preliminarily stored based on the frequency usage pattern information shown in FIG. Start the operation to measure the reception level. Then, when the radio frequency f6 having the highest reception level is identified, it is stored again in advance in FIG.
Based on the information on the frequency usage pattern shown in (4), it is determined whether the identified radio frequency f6 having the highest reception level is present in the same radio base station area as the currently captured radio frequency f2. 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 the mobile station moves to another medium radio zone, the moving body 105
To the switching center 100 at the currently acquired radio frequency f3,
Request a radio channel switch to radio frequency f6. Upon receiving the request, the switching center 100 instructs the mobile unit 105 to switch to a vacant radio channel CHO in the downlink frame 121 and the uplink frame 122 which are set independently of the above-mentioned frames 119 and 120, and wired. The 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 switching center 100 via the currently captured radio frequency f2, the mobile unit 105 changes the radio frequency to be captured to f6 and f7, and the instructed downlink frame 121 and uplink frame 122. Radio channel within, upstream and downstream frames 12
The call is continued on the 1,122 channel CHO. By this, the wireless zone switching from the medium wireless zone 110 to the medium wireless zone 111 is performed, and the call between the mobile unit 105 and the telephone subscriber existing in the other network is performed by the channel and the wired line, and the wireless frequency. Will be changed.

[0012]

As described above, according to the present invention, a plurality of small wireless zones are combined to form one wireless base station area (medium wireless zone), and one wireless base station is arranged in this medium wireless zone. In addition, a means for providing a wireless relay station under the control of a wireless base station, which is wirelessly connected separately by a directional antenna, with different radio frequencies, and the mobile unit itself monitors the reception electric fields of different radio frequency signals in the middle radio zone. By including means for selecting a radio frequency having a strong reception electric field, it is possible to reduce the number of radio base stations under the control of the exchange. Also, the communication method from the exchange to the mobile is TDM.
By adopting the TDMA method as the communication method in the opposite direction, the exchange station only designates the time division channel, performs the exchange operation, and selects the wired route to the radio base station, which reduces the burden on the exchange station. There is.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of wireless zones and wireless frequencies in the embodiment of FIG.

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

[Explanation of symbols]

100 mobile telephone switching center (switching center) 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 Omnidirectional antenna 117, 118 Directional antenna 119, 121 Downstream frame 120, 122 Upstream frame 123, 124, 310, 311 Wired line

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H04Q 7/36 7304-5K H04B 7/26 104 A 7304-5K 108 B

Claims (2)

[Claims] 1. A mobile telephone subscriber terminal (hereinafter referred to as a mobile body) that switches at least radio frequencies when moving between radio zones covered by a plurality of radio base stations, respectively.
In a wireless zone switching system in a mobile telephone switching system, which comprises a mobile telephone switching center for connecting communication information of the mobile unit to the other telephone switching network by wire connection through the wireless base station, the wireless base A wireless zone covered by a station is divided into a plurality of small zones, a wireless relay station under the control of the wireless base station arranged in each of the small zones, and the wireless relay station for wirelessly connecting to the wireless base station. A wireless zone switching system comprising: a directional antenna, wherein the number of the wireless base stations connected to the mobile telephone switching center by wire is reduced. 2. The mobile telephone exchange station has a radio frequency switching instruction means assigned to each radio base station, and a time division channel assignment instruction means for exchanging communication information with the mobile object. , The mobile unit monitors at least a reception level from a radio base station and a radio relay station in the radio zone, a storage unit that stores radio frequency data corresponding to each radio zone and the small zone, and the monitoring unit. 2. The wireless zone switching system according to claim 1, further comprising switching means for switching based on the information stored in the storage means and the storage means.