JPH05110503A - Mobile communication circuit control method and mobile station equipment - Google Patents

Abstract

PURPOSE:To flexibly operate a mobile communication system by changing arbitrarily the frequency and the number of temporary control channels by a base station side without improving a mobile station. CONSTITUTION:A mobile station searches and selects a useable control channel among frequency range in which a mobile station can be operated. Also, after the control channel is selected, the useable control channel is stored in a memory 8 of the mobile station. Moreover, whenover the mobile station selects the channel, history of its selection is also stored in advance, and in the case a change of the channel is generated, a candidate of the control channel to be used is determined from channel history. Furthermore, a temporary control channel code used in a peripheral cell is informed to the mobile station, and the mobile station shortens a search time by detecting its code.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention divides one service area into a plurality of radio cells and carries out communication between a base station and mobile stations of those radio cells. In particular, the present invention relates to a mobile station control channel and a control method for the mobile station.

[0002]

2. Description of the Related Art In mobile communication, a service area covering a wide area is divided into several radio cells, and a base station is arranged in each radio cell. A mobile station control system is known in which a communication channel is designated by using a control channel between the base station and a mobile station in a wireless cell (for example, "Electronic Information and Communication Handbook", 2nd volume, Showa era). March 30, 1988,
Published by Ohmsha Co., Ltd., pp. 2473-2481). In this case, a method is used in which a mobile station first receives a predetermined control channel (hereinafter referred to as a temporary control channel), and the base station controls the mobile station. In the past, in order to shorten the time for the mobile station to search for the temporary control channel, the frequency of the temporary control channel is limited and written in the nonvolatile memory of the mobile station as a temporary control channel code from the time of shipment. .. As a result, the mobile station can search for a usable temporary control channel in the channel code written in the non-volatile memory at the same time when the power is turned on, and receives the control signal from the base station according to the channel frequency. Was.

[0003]

As described above, in the past, the temporary control channel code was written in the nonvolatile memory of the mobile station from the time of shipment, so that it is used for mobile station control by changing the system conditions. When the number of temporary control channels is increased, it is necessary to repair the mobile station. That is, wherever the mobile station of the mobile subscriber moves, the temporary control channel code written in the non-volatile memory must be rewritten in order to receive the service without any inconvenience. as a result,
The operator side has a problem that every time the number of temporary control channels is increased or decreased, or every time the frequency of the temporary control channel is changed, all mobile stations must be repaired. Further, since the number of temporary control channels is determined by the radio area having the highest traffic of all service areas, there is a problem that the frequency is not effectively used.
Further, when a certain temporary control channel receives interference such as interference, there is a problem that the channel cannot be used. An object of the present invention is to solve these conventional problems and to control a mobile communication line capable of accessing the changed temporary control channel without modifying the mobile station even when the number of temporary control channels increases or decreases. A method and a mobile station device are provided.

[0004]

In order to achieve the above object, in the mobile communication line control system of the present invention, (a) one service area is divided into a plurality of wireless cells, and each wireless cell is provided. In the mobile communication line control method, the mobile station controls the mobile station by receiving a predetermined control channel for communication between the base station and the mobile station. When the cell is turned on or when the electric field level is lowered by moving the cell, the mobile station searches for a control channel such that the received electric field level satisfies the required value based on a predetermined frequency arrangement. There is. Further, (b) the mobile station receives a control channel code used in a wireless cell in the vicinity of the wireless cell on the control channel in use and moves from the wireless cell to another wireless cell. Another feature is that the control channel of the transfer destination wireless cell is searched by referring to the control channel code of the peripheral wireless cells. Further, in the mobile station device of the present invention, (c) one service area is divided into a plurality of radio cells, and the mobile station device is predetermined in order to communicate with a base station provided in each radio cell. In a mobile station that receives a control channel that has been used, a storage device that stores all available control channels, and if the control channel being used becomes unusable due to a decrease in the electric field level, the next control And a means for setting the frequency range of the transceiver by reading the channel. Further, (d) the storage device stores a history of control channels that are sequentially selected when the mobile station moves between wireless cells, and when a request for changing the control channel occurs, the mobile station moves. Another feature is that the control channel candidates used by the station are determined from the control channel history.

[0005]

According to the present invention, the mobile station autonomously searches for the temporary control channel without writing the code of the temporary control channel to the mobile station, so that the changed temporary A control channel can be used. Therefore, (a) the mobile station searches for, selects, and uses a control channel that can be used by itself after power-on from the frequency range in which the mobile station can operate. (B) In addition, the base station informs the mobile station of the control channel used in the neighboring cells, so that when the electric field level of the control channel being used is lowered, the mobile station can move to the next control channel. Is selected from the broadcasted channels.
(C) Further, the mobile station stores all available control channels in the storage device, and when the electric field level of the control channel in use drops, the mobile station uses the next stored control channel. .. (D) Furthermore, the mobile station selects the control channel with the highest received electric field level after power-on,
When the control channel is sequentially selected and changed due to the shift of the mobile station, the order of the channels is written in the channel history, and when the mobile station shifts back to the same route and returns, the previous one recorded in the channel history is written. Select control channel. As a result, the mobile station can search for the control channel by itself in a short time without repairing the mobile station.
On the other hand, the base station side can independently change the frequency and number of control channels, which enables flexible system operation.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 3 is a diagram showing a configuration of a service area and an arrangement of temporary control channels in a mobile communication system to which the present invention is applied, and FIG. 5 is a diagram of a frequency arrangement for control channel search in FIG. In FIG. 3, one of the small circles represents the service area. Each service area slightly overlaps with the adjacent area. Fn in the service area represents a frequency group including the temporary control channel. Here, f _{1 to} f ₆ are arranged, but the same frequency is not arranged in adjacent areas, but different fn are arranged. As shown in FIG. 5, f _{1 to} fN are arranged as frequencies for control channel search. (A) In the first embodiment, when the mobile station is powered on, and when the cell is moved and the electric field level is lowered, for example, the frequency group of f ₁ is based on the frequency arrangement shown in FIG. The search is started from and is continued until the temporary control channel whose received electric field level satisfies the required value is selected. f ₁ to fn are radio base station is a frequency range that can be fired. Now, consider a case in FIG. 3 in which a mobile station moves from point A in the service area of f ₆ to point B in the service area of f ₄ . When the mobile station turns on at point A,
The mobile station continues the search until it selects the temporary control channel of the f ₆ group. Furthermore, when the mobile station moves from the point A to the point B, the electric field level of the temporary control channel of the f ₆ group decreases, so that the search for the usable temporary control channel is started again, and the f ₄ group The search is continued until the temporary control channel group is selected.

FIG. 4 is a diagram showing a cell structure and a temporary control channel structure according to an embodiment of the present invention. (B) In the second embodiment, the temporary control channel code used in the neighboring cells is notified by the temporary control channel in the own radio cell, and the mobile station detects this to notify the time of the cell transition. The temporary control channel search time can be shortened. The cell structure is shown in FIG. 4A, and f ₂ is shown in FIG.
The respective configuration examples of the temporary control channel of the base station having the f ₁₀ group are shown. In this example, when the mobile station is located in the shaded cell, the temporary control channels of the f ₂ group are received, and the temporary control channels in the peripheral zones are f ₄ , f ₅ , f.
It is possible to detect 6 frequency groups of ₆ , f ₁₀ , f ₁₂ , and f ₁₃ , and when the level of f ₂ deteriorates, search the temporary control channel of the destination cell from the 6 frequency groups. .. Further, when the mobile station in the cell in the lower left f ₁₀ is located in the peripheral zone to the mobile station - the temporary control channel f ₁ in _{emissions, f 2, f 6, f} 7, f 11, f 12 6 The frequency is notified by the individual information part for each cell. This allows
The temporary control channel of the target cell can be searched from these 6 frequency groups. In this embodiment, the example in which the control channels are arranged regularly has been shown, but a similar method can be used even when the control channels are arranged irregularly. Further, although the method of geographically limiting the temporary control channel is used here, a method of limiting the frequency that can be used as the temporary control channel is also conceivable.

(C) The third embodiment is a method in which the mobile station stores a usable control channel after selecting the control channel. In FIG. 3, consider a case where the mobile station is powered on at point C in the service area where f ₄ and f ₂ overlap, and then moves from point C to point D in the service area at f ₂ . At point C, it is possible to use both f ₂ and f ₄ control channels of the temporary control channels due to the overlap in the service area. When the mobile station searches for a temporary control channel, it stores all available channels in memory. Since the next control channel in use can be used, it is not necessary to search for the control channel at the time of transition to the overlapped cell. In the example of FIG. 3, the control channel of the f ₂ group can be used when the electric field level of the temporary control channel of the f ₄ group decreases. A semiconductor memory is used as a method for the mobile station to store usable frequencies.

FIG. 1 is a block diagram of a mobile station showing an embodiment of the present invention, and FIG. 6 is a diagram showing contents of a storage table of an available control channel. In FIG. 1, 1 is a handset, 2 is a baseband processing unit, 3 is a transmitter, 4 is a receiver, 5 is an antenna duplexer, 6 is an antenna, 7 is a processor, and 8 is a storage device. In the mobile station, the storage device 8
By storing all the control channels available to the processor, the processor reads one of them from the storage device 8 and controls the base band processing unit 2 to transmit the frequency range transmitted from the transmitter 3, And the frequency range received by the receiver 4 is set. With the set frequency,
The voice signal transmitted by the handset 1 is sent from the transmitter 3 to the antenna 6 through the antenna duplexer 5, and the antenna 6
From the cell base station. In addition, the signal from the cell base station is transmitted from the antenna 6 to the receiver 4 via the duplexer 5.
Is input to the handset 1 from the baseband processing unit 2.
To be an audio signal. In the storage device 8, as shown in FIG. 6, storage tables of usable control channels are stored. Here, the case of moving from point C to point D in FIG. 3 is shown, and f ₂ and f ₄ are registered as usable control channel frequencies.

FIG. 2 is a flowchart of the control operation of the mobile station showing an embodiment of the present invention, and FIG. 7 is a diagram showing a temporary control channel history table stored in the mobile station. Is. (D) In the fourth embodiment, consider a case in which the mobile subscriber repeatedly travels back and forth between points E and F in FIG. When the power of the mobile station is turned on at point E, first, the temporary control channel f ₉ having the highest received electric field level is selected from all the control channels. With the movement of the mobile station, the control channels are sequentially selected from f ₁₂ , f ₂ and f _5, and are sequentially written in the temporary control channel history table shown in FIG. 7 to reach point F. Next, when moving from point F to point E again, when the reception electric field level of the control channel f ₅ drops,
The control channel f ₂ immediately before the history table is selected.
Further, the control channels f ₁₂ and f ₉ one by one are selected, and the point E is reached. In this case, the temporary control channel of the mobile station can be determined without the mobile station searching for a candidate for the temporary control channel. In FIG. 2, it is determined whether the control channel needs to be changed (step 10
1), if necessary, 1 from the control channel history table
The previous control channel is set as a change candidate (step 10).
2). Then, it is determined whether or not the received electric field level of the control channel candidate is equal to or higher than a specified value (step 103), and the process returns to step 101 to determine whether or not the control channel needs to be changed. If the received electric field level is equal to or lower than the specified value, all control channels are searched for usable channels (step 10).
4). Then, the control channel history is written in the history table (step 105). In this embodiment, for example, in the case of a truck that goes back and forth between an office and a factory, it is possible to determine the control channel without searching for a temporary control channel. Also, here, the history table of the mobile station history is
Although the method of referring to the immediately preceding table is described, another method of searching, for example, a method of sequentially searching from the oldest history table and referring to the same temporary control channel number in the forward direction is also conceivable. .. There is also a method of referring to these combinations.

[0011]

As described above, according to the present invention,
The frequency and number of temporary control channels in the mobile communication system can be arbitrarily changed on the base station side, and in that case, there is no need to modify the mobile station, so that flexible system operation is possible. .. Further, even when one of the temporary control channels becomes unusable due to interference or the like, the system operation can be smoothly performed by simply switching the frequency of the temporary control channel on the base station side.

[0012]

[Brief description of drawings]

FIG. 1 is a configuration diagram of a mobile station showing an embodiment of the present invention.

FIG. 2 is a control operation flowchart of a mobile station showing a fourth embodiment of the present invention.

FIG. 3 is a configuration diagram of a service area of a mobile communication system to which the present invention is applied.

FIG. 4 is a diagram showing a cell structure and a temporary control channel structure according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a frequency allocation example to which the present invention is applied.

FIG. 6 is a diagram of a usable control channel storage table showing a third embodiment of the present invention.

FIG. 7 is a diagram of a temporary control channel history table showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1 Handset 2 Baseband Processor 3 Transmitter 4 Receiver 5 Antenna Duplexer 6 Antenna 7 Processor 8 Storage Device

Claims (4)

[Claims] 1. A service area is divided into a plurality of radio cells, and a predetermined control channel is used for communication between a base station and a mobile station provided in each radio cell. In a mobile communication line control method for controlling a mobile station by reception by the mobile station, when the mobile station is powered on or when a cell is moved to lower the electric field level, the mobile station Is a method for controlling a mobile communication line, which searches for a control channel such that a received electric field level satisfies a required value based on a predetermined frequency arrangement. 2. The mobile communication line control method according to claim 1, wherein the mobile station receives a control channel code used by a radio cell in the vicinity of the radio cell, by a control channel being used. Then, when migrating from the wireless cell to another wireless cell, the mobile channel is characterized in that the control channel of the wireless cell to be migrated is searched by referring to the control channel code of the peripheral wireless cell. Line control method. 3. A mobile station in which one service area is divided into a plurality of radio cells and which receives a predetermined control channel for communication with a base station provided in each radio cell. In a storage device for storing all available control channels, and when the control channel being used becomes unusable due to a decrease in the electric field level, the next control channel is read from the storage device and the transceiver And a means for setting the frequency range of the mobile station apparatus. 4. The mobile station device according to claim 3,
When the mobile station moves between radio cells, the storage device stores a history of sequentially selected control channels, which is used by the mobile station when a control channel change request occurs. A mobile station apparatus, characterized in that a control channel candidate is determined from the control channel history.