JPH08289362A - Control channel selecting system for mobile station - Google Patents

Abstract

PURPOSE: To extremely reduce the current consumption of a mobile station by intermittently measuring the reception levels of a part of plural control channels stored in the mobile station till detection of a channel whose reception level is equal to or higher than a prescribed value. CONSTITUTION: The first control channel selection mode is provided where reception levels of a part of plural control channels preliminarily stored in a mobile station are successively and intermittently measured till detection of a control channel whose reception level is equal to or higher than a first prescribed value. The second control channel selection mode where reception levels of all of control channels preliminarily stored in the mobile station are measured is provided. Concretely, the second control channel selection mode is executed after execution of the first control channel selection mode. In a system which receives plural control channels, it is forecasted whether the present zone is in the service area or not without measuring the reception levels of all channels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control channel selection system in a mobile station in which a mobile station detects a control channel for standby in a two-way mobile communication system such as a car telephone and a mobile telephone.

[0002]

2. Description of the Related Art When a mobile station selects control channel candidates for standby, all reception levels of control channels preset in the mobile station are measured. As a result of the measurement, if there is a control channel having a reception level equal to or higher than a specified value, it is determined whether or not the control channel is ready for standby, and if it is determined that the control channel is ready for standby, the control channel is used for standby. Also, the detection result of the reception level,
If the reception levels of all control channels are less than the specified value, the reception levels of all control channels are measured again.

This reception level measurement is repeated until a control channel with a reception level higher than a specified value is detected.

[0004]

As described above, in the mobile station, the reception level is repeatedly measured until the control channel having the reception level higher than the specified value is detected. Therefore, the mobile station is out of the service area. In this case, the reception level of the control channel is repeatedly measured, which causes a problem that battery consumption is accelerated in a mobile mobile station or the like.

The present invention has been made in view of the above,
An object of the present invention is to provide a control channel selection method in a mobile station that detects a control channel for standby while suppressing current consumption in the mobile station.

[0006]

In order to achieve the above object, the present invention according to claim 1 is a mobile communication system for performing bidirectional wireless communication, in which a mobile station selects a control channel candidate for standby. In the case of selecting, a first control is performed by intermittently measuring a part of the control channels stored in the mobile station in advance until a control channel whose reception level is equal to or higher than a specified value is detected. A control channel selection mode and a second control channel selection mode for measuring reception levels for all control channels stored in advance in the mobile station are provided, and as a result of executing the first control channel selection mode, a reception level If a control channel with a value greater than or equal to the specified value is detected, the second control channel selection mode is executed to find the optimum control channel for the zone. -Option and, if the optimal control channel in the second control channel selection mode can not be selected, and gist performing said first control channel selection mode again.

The present invention according to claim 2 provides the invention according to claim 1.
In the invention described above, in the first control channel selection mode, a plurality of control channels stored in the mobile station are divided into a plurality of groups, and the reception level is sequentially measured for the control channels of each group. And

[0008]

In the first aspect of the present invention, the reception level of some control channels among the plurality of control channels stored in the mobile station in the first control channel selection mode is equal to or higher than the specified value. Measurement is performed intermittently until the control channel is detected. As a result, if a control channel with a reception level higher than a specified value is detected, it is stored in the mobile station in the second control channel selection mode. The reception level is measured for all control channels, the optimum control channel in the zone is selected, and when the optimum control channel cannot be selected in the second control channel selection mode, the first control channel selection mode is used. And try again.

According to the present invention of claim 2,
In the first control channel selection mode, the plurality of control channels are divided into a plurality of groups, and the reception levels of the control channels of each group are sequentially measured.

[0010]

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

FIG. 1 is a flow chart showing the operation of the control channel selection method in a mobile station according to an embodiment of the present invention. In the embodiment shown in the figure, some control channels among a plurality of control channels stored in advance in the mobile station are sequentially intermittently received until a control channel whose reception level is equal to or higher than a first specified value is detected. The first control channel selection mode to be measured in and the second control channel selection mode to measure the reception level for all control channels stored in the mobile station in advance are provided, and the first control channel selection mode is executed. After that, the second control channel selection mode is executed.

Here, in a system capable of receiving a plurality of control channels in an arbitrary zone, it is possible to predict whether or not the zone is a service area without measuring the reception levels of all the control channels. . Therefore, in the first control channel selection mode, a plurality of, for example, N wave control channels CH (1), CH (2), ..., CH (N) stored in advance in the mobile station are grouped into a plurality of groups. For example, it is divided into G groups, and the reception level is measured for each group to predict whether or not the zone is a service area.

The grouping can be arbitrarily performed, for example, in the following patterns 1, 2, 3 and the like. Here, for the sake of explanation, the total number of control channels is 50 waves (N =
50), and this is divided into 5 groups (G = 5).

Pattern 1: First group = CH (1), CH (2), ..., CH (1
0) Second group = CH (11), CH (12), ..., CH
(20) Fifth group = CH (41), CH (42), ..., CH
(50) Pattern 2: First group = CH (1), CH (6), ..., CH (4
6) Second group = CH (2), CH (7), ..., CH (4
7) Fifth group = CH (5), CH (10), ..., CH (5
0) Pattern 3: A method of randomly assigning to the first to fifth groups.

Of course, it is possible to arbitrarily divide into groups by a method other than the above patterns 1 to 3.

Description will be given according to the procedure shown in FIG. In addition,
In FIG. 1, G is the number of control channels divided into groups, g is the group number (g = 1 to G), N is the number of control channels stored in the mobile station, and n is the number of control channels per group ( n = N
/ G).

In FIG. 1, first, a variable g for designating a group
Is set and this variable g is set to 1 (g =
1), the first group is selected (step S11). Then, the reception level of the nth wave control channel of the selected g-th group (first group) is measured (step S12). In the case of the pattern 1, the control channels CH (1), CH
(2), ..., Receive levels of 10 waves of CH (10) are measured.

As a result of the reception level measurement, it is determined whether or not there is a control channel having a reception level equal to or higher than the first specified value (L1) (step S13). This judgment result,
If there is no control channel having a reception level equal to or higher than the first specified value (L1), the process proceeds to step S14, power of the receiving unit is turned off for a predetermined time T, and after the predetermined time T elapses, Select a control channel (step S1)
5). In this case, the second group of control channels is selected. In this case, when the variables g = 1 to (G-1), the variable g = g + 1, and when the variable g = G, the variable g = 1 and the process returns to the first group.

In this way, when the next group is selected, the process returns to step S12, the reception level of each control channel of this selected group is measured, and the first group is selected from this reception level as in the case described above. It is determined whether or not there is a reception level equal to or higher than the specified value (L1) of 1 and a loop of steps S12, ... Is repeated.

As a result of the above measurement of the reception level, when there is a control channel having the reception level equal to or higher than the first specified value (L1), it is predicted that the zone is the service area, and the steps after step S16. Proceed to the second control channel selection mode.

In the first step S16 of the second control channel selection mode, all control channels CH (1), CH (2), ... Of N waves stored in advance in the mobile station are ...
., Measure the reception level of CH (N) (step S1)
6). Then, from the measured reception levels of all the control channels, it is determined whether or not there is a control channel having a reception level equal to or higher than the second specified value (L2) (step S17). When the control channels having the reception level equal to or higher than the second specified value (L2) are detected, the control channels having the higher reception levels are sequentially checked for those control channels (step S18).

In the standby availability determination, a signal is received for the selected control channel, and it is determined whether or not the control channel is capable of standby for incoming calls and outgoing calls. This determination method differs depending on the mobile communication system to which the present invention is applied.

When it is determined by the standby availability determination that standby is possible, the standby or outgoing call of the incoming call on the control channel is performed (step S19).

In step S17, the second specified value (L
2) Even if no control channel having a reception level of not less than 2 is detected, or if a control channel having a second specified value (L2) or more is detected, all control channels detected in the standby availability determination in step S18 If it is determined that standby is not possible, the process returns to the first step S11 to shift to the first control channel selection mode again, and the service area is predicted.

Next, the effect of the present invention will be described with reference to FIG. 2A is a timing diagram showing the operation of the conventional control channel selection system, and FIG. 2B is a timing diagram showing the intermittent operation of the control channel selection system of the present invention. In FIG. 2, N is the number of control channels stored in advance in the mobile station, T is the power-off period of the receiver in the first control channel selection mode, and G is the number of control channel groups (G = 1). To N groups), n is the number of control channels per group (n = N / G), t is the control channel reception level measurement time per wave, A1 is the current consumption value during reception level measurement, A0 Is the current consumption value when the power of the receiving unit is off.

As shown in FIG. 2A, in the conventional control channel selection method, the receiving section is always on, and the average value Aavc of the current consumption is A1 (mA).

On the other hand, in the control channel selection method of the present invention, since the operation is intermittent as shown in FIG. 2B, the average value Aavi of the current consumption is

[Equation 1] Aavi = {(n × t) × A1 + T × A0} /
(N × t + T).

Here, in order to more clearly show the effect, A0 = 10 mA A1 = 100 mA T = 1 second n = 10 waves (N = 50 waves, G = 5 groups) t = 10 ms The current consumption Aavc of the conventional method is Aavc = 100 mA, and the current consumption Aavi of the method of the present invention is Aavi = 18 mA.

In the above-described embodiment, in a place where the control channel cannot be received, such as a tunnel, underground, building, etc., the control of the mobile station is to repeatedly execute the first control channel selection mode, and to periodically perform the predetermined control. Since the power supply of the receiving unit is turned off for the time T, the current consumption can be suppressed.

[0030]

As described above, according to the present invention,
For some control channels among the control channels stored in the mobile station, the reception level is measured intermittently until a control channel with a reception level higher than a specified value is detected. In addition, since the measurement is not always performed continuously, the current consumption can be suppressed to a very low level and the battery consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a flowchart showing an operation of a control channel selection method in a mobile station according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for comparing the effects of the control channel selection method and the conventional control channel selection method in the mobile station of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ya ▲ Saki ▼ Hidetoshi Toranomon 2-10-1 Toranomon, Minato-ku, Tokyo NTT Mobile Communications Network Co., Ltd.

Claims (2)

[Claims] 1. In a mobile communication system for performing two-way communication wirelessly, when a mobile station selects a control channel candidate for standby, among the plurality of control channels stored in the mobile station in advance. First control channel selection mode in which the control level of some control channels is intermittently measured until a control channel with a specified level or more is detected, and all control channels stored in advance in the mobile station are received. A second control channel selection mode for measuring the level is provided, and as a result of executing the first control channel selection mode, if a control channel with a reception level equal to or higher than a specified value is detected, the second control channel Execute the selection mode to select the optimum control channel in the zone, and select the optimum control channel in the second control channel selection mode. A control channel selection method in a mobile station, characterized in that the first control channel selection mode is executed again when the control channel selection mode cannot be achieved. 2. In the first control channel selection mode, a plurality of control channels stored in a mobile station are divided into a plurality of groups, and a reception level of the control channels of each group is sequentially measured. The control channel selection method in the mobile station according to claim 1.