JPS5847343A - Busy channel switching method for mobile communication system - Google Patents

Abstract

PURPOSE:To facilitate a switching operation of channels, by adding a function to detect the moving direction of a mobile station to a radio base station. CONSTITUTION:A mobile station 2 goes away from a radio base station S, and the receiving level of a signal receiver 8 lowers. Thus a controller 9 informs the moving direction of the station 2 and a reduction of the receiving level to a control station 3 via a link line 14. The station 3 designates a radio base station closest to the radio zone in the moving direction of the station 2 and then sets newly a radio circuit at the station S to the station 2.

Description

[Detailed Description of the Invention] The present invention is a method for switching channels during a call, which occurs occasionally when base stations are installed in a distributed manner and a mobile station during a call through one of the base stations moves to the radio zone of another base station. Regarding.

As shown in FIG. 1, in the conventional channel switching method of this type, when the mobile station 2 moves to the wireless zone ZsK while the mobile station 2 is talking through the wireless base station 51t within one wireless zone zi, the control station 3 detects a decrease in the electric field strength or deterioration of the S/N of the radio wave of the mobile station 2 received by the base station S1, and at the same time detects the decrease in the field strength or the deterioration of the S/N of the radio wave of the mobile station 2 received by the base station S1, and at the same time The mobile station 2 instructs the mobile station 2 to monitor the level of radio waves received by the mobile station 2. The control station 3Fi determines that the mobile station 2 is present in the radio zone of the station whose reception level or 8/NO& is higher among the radio base stations BS-'-S, and transfers the call a (call channel) to the radio base station SI. From that station,
For example, switch to Sm. In this case, if the number of nearby wireless base stations increases or the mobile station moves to another control station zone and stops, control such as level comparison performed by control station 3 becomes complicated, and each wireless base station This method has the drawback of increasing unnecessary level monitoring.

In order to eliminate these drawbacks, the present invention aims to provide a method for switching channels during a call that facilitates the operation of switching channels by adding a function to the wireless base station to detect the moving direction of a mobile station. .

FIG. 2 shows an embodiment of the present invention, in which a plurality of antenna elements 4 in a radio base station 8 are each connected to a circulator 6 through a phase shifter 5, a transmitter 7 and a receiver 8 are connected to the circulator 6, These transmitter 7, receiver 8
is also connected to the control unit [9]. Further, a directional antenna 11 is provided, and the directional direction of this antenna 11 is rotated by an antenna rotation motor 12. The directional antenna 11 is also connected to a level monitoring receiver 13, and the receiver 13 is also connected to the control device 9. Connected. Control device 9 is in contact! 1
14 to the control station 3.

The plurality of antenna elements 4 are always fed with power in the same phase and appear in an omnidirectional antenna pattern.

At this time, when the mobile station 2 makes a call, the receiver 8 detects the signal and establishes a wireless link between the mobile station 2 and the base station S. When the setting of the wireless line is completed, the directional antenna 11 and the level monitoring receiver 13 receive the radio waves from the mobile unit 2,
Start monitoring its level. The reception frequency of the level monitoring receiver 13 is set to be the same as that of the receiver 8. The directional antenna 11 is rotated in the finger direction by the motor 12, and the radio wave intensity from the mobile station 2 at the directional receiver 13 is improved by the direction K of the antenna 110. The antenna 11 may be a play antenna, and its pointing direction may be electrically rotated. Control if9 determines the direction of mobile station 2 based on field strength information from receiver 13 and directional rotation angle information of antenna 11 from motor 12.

When the mobile station 2 moves away from the radio base station S and the reception level at the receiver 8 decreases, the control device 9 notifies the control station 3 of the direction in which the mobile station 2 has moved and the level drop!
Notify via 114.

? 1ill m station 3 specifies the wireless base station closest to its own wireless zone in the direction in which mobile station 2 has moved, and causes that wireless base station to set up a new wireless line (channel) with mobile station 2. .

Although it is possible to use only one antenna as the antenna element 4, the antenna beam of the antenna element 4 can be adjusted in the direction of the mobile station 2 based on the information from the motor 12.
It is also valid to spell antenna 11, motor 1
2 and level monitoring receiver 13 Kl! 1111i
I! The device 9 may be configured to appropriately control the phase shifter 5 so that the reception level of the receiver 8 is maximized, and detect the direction in which the mobile station 2 is present from the phase setting value of the phase shifter 50. . The transmission frequency of the transmitter 7 is set by the control device 9 based on instructions from the control station 3.

As explained above, according to the present invention, each wireless base station can uniquely know the location of a mobile device, so it is possible to disconnect the channel during a call. There is an advantage that (zone switching) can be performed extremely easily. Especially as a mobile station, there is no 1jvg like Bokuto Bell! When many mobile stations make calls using M, with radio base stations installed in various places such as public telephones, the VbIJ station 3 balance burden is extremely large in the conventional system, and it cannot actually be handled. However, by using this invention, channels can be switched during a call with fewer operations. The mobile station 2 is a car phone, a mobile phone stand, or the like.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a wireless zone, a wireless base station, and a mobile station for explaining a conventional channel switching method, and FIG. 182 is a block diagram showing an example of the configuration of a wireless base station used in the method of the present invention. . 2: Mobile station, 3: Control station, 4: Antenna element, 5: Phase shifter, 6: Circulator, 7: Transmitter, 8: Receiver, 1
1: Directional antenna (variable directional antenna), 12: Antenna rotation motor (antenna directivity control device), 1
3-level monitoring receiver, 92 control device l Patent applicant: Nippon Telegraph and Telephone Public Corporation I Agent: Taku Kusano 7i'1 Fig. 3 72 Fig.

Claims (1)

[Claims] (1) When communicating between a wireless base station and a mobile station in a mobile communication system in which multiple wireless base stations are installed in a distributed manner, the wireless base station changes the directivity direction of its antenna and The direction in which the mobile station is located is detected based on changes in the reception level of radio waves from the mobile station at that time, and when the mobile station moves to another wireless zone, the wireless zone to which it moved is determined based on the direction information. A method for switching channels during communication in a mobile communication system, characterized in that: