JP3148572B2 - Mobile communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for economically realizing a large-capacity mobile communication system with effective use of frequency.

[0002]

2. Description of the Related Art In realizing a large-capacity mobile communication system in a limited frequency band, it is essential to improve the frequency utilization rate by repeatedly using frequencies locally.

For this reason, a method is used in which a service area is divided into small zones, base stations are arranged in each zone, and a plurality of radio channels are assigned in units of some base stations.

Conventionally, in a mobile communication system having such a small zone configuration, a control station is arranged to control a base station in order to cover a wide service area, and all mobile stations (also called PSs) are base stations. A centralized control system under the control of was used. Then, a control line for communication is provided between the control station and the base station and between the base stations. In setting a communication channel, an unused one of radio channels fixedly assigned in advance in the base station is set. A method of allocating the channel has been used.
However, an increase in the number of channels has led to an increase in the system cost of the base station.

On the other hand, unlike the centralized control system, an M-type using a distributed control system without such a central control station is used.
There is an A cordless telephone. In this case, a service area is set in units of a calling station (covering a plurality of base stations) corresponding to a rosette or a PBX.
Since the mobile station does not have a control function related to location registration, it has not been possible to realize a wide service area using a large number of calling stations.

Accordingly, Japanese Patent Application Laid-Open No. 62-179230 (H
04B 7/26) There is a position registration method for mobile radio communication as shown in the gazette. In other words, this is a mobile communication system provided with a location registration function, and a service can be used in any of the service areas of a plurality of base stations.

More specifically, when the mobile station enters the service area, it receives the ID transmitted from the base station covering the service area and compares it with the I degree stored up to that time. And if they do not match, transmit the ID code of the mobile station to the base station, perform location registration,
The ID of the base station is stored in the mobile station.

This technology is based on, for example, a PDC (Personal Digital Cellular Telecommunicatio) based on the "Digital Car Phone System Standard" described in RCR STD-27, which is a standard of the Radio System Development Center.
PHS based on “2nd generation cordless telephone system standard” shown in RCR STD-28
(Personal Handy / phone system).

[0009] Here, the communicable area of the base station using the PHS system will be described. This base station has a communicable determination level (electric field strength level) as area information defining an area in which communication is possible for each base station.

[0010] This communication availability determination level may be different in different base stations, different base stations may have different values, or a plurality of base stations may be used as paging areas in a service area of a certain calling station. They may be placed and have the same value.

When the mobile station uses a communication channel (also referred to as a TCH), such as at the time of location registration or at the time of a call, the base station passes the data of the communication availability determination level to the mobile station. Then, based on the data, the passed mobile station determines whether or not the current reception level is equal to or higher than the communicable determination level indicated by the data. Area) and communicate with the base station. Thereby, it is possible to always realize communication in an area (area) where the wireless state is good.

The configuration of a mobile station for realizing this will be specifically described with reference to the circuit block of FIG.

The RF / IF unit 1 receives a radio signal from an antenna during reception and converts a high-frequency signal into a signal in an intermediate frequency band, and converts a signal in the intermediate frequency band into a high-frequency signal during transmission. I do. The reception level detector 2 detects the received level. The level comparison unit 3 compares the judgment level from the level memory 4 storing the preset communication possible judgment level with the reception level from the reception level detection unit 2 and notifies the result (notifies by display or sound). Output to the notifying unit 5. If the reception level is higher than the determination level, it is determined that the reception level is within the receivable area and the area is notified. This determination level is received from the base station whose location is registered, and may have a different value depending on the base station.

The modulation / demodulation unit 6 modulates / demodulates the IF band signal by π / 4 shift four-phase QPSK, and performs digital signal processing such as TDMA processing. The ID discriminating unit 8 compares the base station ID of the data transmitted from the base station with the immediately preceding ID stored in the ID memory 9 of the mobile station. The processing is performed by the position registration unit 7, and the base station ID of the current service area is stored in the level memory 4. At the time of this location registration processing, the communicable determination level is also changed and updated to the value from the base station. On the other hand, if they match, the location registration is not performed, and the communication availability determination level is not changed, and the call can be performed as it is.

Next, this conventional example will be described with reference to the flowchart of FIG.

First, it is assumed that the mobile station is set to the out-of-service state. In step 101, the power is turned on, and in step 102, the setting state is out of service, so that out-of-service notification is performed. At this time, if it is detected whether the mobile station is in the service area or has moved into the service area, the reception level is detected in step 103. In step 104, the detected reception level is compared with the judgment level LL registered in the mobile station. If the reception level is higher than the determination level LL in step 104, the process proceeds to step 106;
Move to

In step 105, the processing is performed when the reception level is lower than the judgment level LL, a notification (display) of out of service is made, and the process returns to step 103. This notification (display) information is maintained until it becomes the next different notification information. On the other hand, in step 106, processing is performed when the reception level is higher than the determination level LL, notification (display) to the effect that the vehicle is within the service area is performed, and the process proceeds to step 107. Step 10
7 is the I of the base station whose mobile station has this mobile station within range.
This is the part that receives and extracts D.

The extracted base station ID is stored in step 108
The registration IDs registered in the mobile station are compared to determine whether they are the same. If they are the same, the process shifts to step 109, the notification of the area is continuously performed, and the process returns to step 103. If they are different, go to step 110,
Perform location registration processing. Thereafter, in step 111, the communication availability determination level of the base station is detected, and in step 112, the communication level is registered in the level memory 4. Thereafter, the process returns to step 103, and the same process is repeated while the power is on.

Therefore, it is possible to recognize that the mobile station is in the service area of the predetermined base station by using the reception level and the communication availability determination level from the base station. Each time, the determination level can be changed, and the user can use in any area without being conscious of which area.

[0020]

In this conventional example, once it is recognized that the reception level has exceeded the communicable determination level, a notification is made within the communication range assuming that the reception level is within the communication range. Therefore,
When the mobile station P1 moves from the base station A to the base station B as shown in FIG. 5A, at the time of turning on the power, the communicable determination level La of the previous base station A is compared with the current reception level Lo, and La <Lo.
Therefore, it is regarded as a communication area, and information in the area is notified.

However, the base station B has an ID different from that of the base station A, and the location registration processing of the mobile station P1 is performed. Therefore, the base station B sets the level at which the electric field strength is higher than that of the base station A as the communicable determination level Lb, and the reception level Lo is out of the communication range because Lb> Lo. Therefore, regardless of the notification that the location was within the communication range, if the location is registered in this way, the location will immediately be out of the communication range, and a notification to that effect will be given, giving the user discomfort and discomfort. It is possible that

On the other hand, when the mobile station P2 moves from the base station C to the base station D as shown in FIG. 5B, the determination level of the base station C is determined in the new base station D even though the mobile station P2 is within the communication range. This causes a problem that the display is out of the service area, and the user is confused.

[0023]

According to the present invention, a plurality of base stations and a radio communication with the base stations within a service area where at least one of the plurality of base stations can be serviced are provided. An identification signal transmitting means for transmitting an identification signal indicating the base station, at least in a service area, and a reception electric field intensity indicating an electric field intensity for limiting a reception range preset by the base station. Receiving level transmitting means for transmitting information, the receiving level detecting means for detecting the electric field strength from the base station provided in the base station, and which of the base stations the mobile station is in a service area of. The identification memory stored in the identification signal of the corresponding base station, the identification signal stored in the identification memory, and the identification signal from the receiving base station are compared. Identification signal determining means for determining that the mobile station is located in a service area of a base station different from the service area of the base station registered in the identification memory, and storing the received identification signal in the identification memory; At the time of a negative output of the signal discriminating means, a position registering means for registering that the mobile station is located in the service area with the base station where the mobile station is located; and A level memory for storing the received electric field intensity information, the received electric field intensity information from the base station whose position has been registered, and the received electric field intensity information already stored in the level memory, under the control of the position registration means. Comparing the output from the level selection means for selecting and outputting, the output from the reception level detection means with the output from the level selection means, There is provided a mobile communication system comprising: the level comparing means for controlling the informing means for informing whether within or out of service, to the mobile station.

[0024]

According to the present invention, the mobile station transmits the identification signal (I) from the base station.
D) is confirmed, and if the ID is different from the ID already stored in the mobile station, the new ID is re-registered, and
A communication availability determination level at which communication with the base station can be reliably performed is acquired from the base station, and whether or not communication is possible is determined using the level.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the block diagram of FIG. The same parts as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 10 denotes a communicable judgment level selection unit which receives the lowest level Lf set by the initial level setting unit 11 and sets the communicable judgment level to the lowest level Lf as an initial value.

The operation will be described with reference to FIG. RF / I
An F unit 1 receives a radio signal from a base station, and a reception level detector 2 detects a reception level L at a point where the mobile station is located.
o is detected.

Then, the reception data is extracted by the modulation / demodulation unit 6, and the base station ID transmitted from the base station included therein is extracted from the reception data.
The base station ID stored in the ID memory 9 of the mobile station is
The comparison is made by the determination unit 8, and if they are the same, the communication is permitted as it is. In this case, the judgment level LL stored in the level memory 4 is selected by the communication possible judgment level selection unit 10 and output to the level comparison unit 3.

However, if they are different, the ID discriminating unit 8 sends a command to the position registering unit 7, and the position registering unit 7 performs a position registration process to the base station via the RF / IF unit 1 and also performs I
The base station I currently covering the mobile station is stored in the D memory 9.
D is stored. At this time, the communicable determination level L1 possessed by the base station is taken into the communicable determination level selector 10. The determination level L1 is input to one input terminal of the level comparison unit 3 and is stored in the level memory 4.

That is, the communicable judgment level selecting section 10 stores the base station ID stored in the base station ID of the received signal.
If it is the same as D, the communication enable determination level LL stored in the level memory 4 is selected, and the base station I of the received signal is selected.
If D is different from the stored base station ID, the location registering unit 7 selects the communication availability determination level L1 of the newly registered base station.

Thus, the set communication availability determination level is compared with the reception level, the information to be notified to the notification unit 5 is determined to be within or outside the service area, and notification is performed.

When the position registration is performed, the controllable signal from the position registration unit 7 controls the communication availability determination level selection unit 1
0 selects the judgment level L1, controls the level memory unit 4, and writes the judgment level L1.

Next, the flow of the operation will be described with reference to the flowchart of FIG.

In step 1, the power is turned on, and in step 2
, The level L set in the initial level setting section
f is selected by the communicable determination level selection unit 10.

On the other hand, in step 3, the level of the reception level detector 2 is detected, and this reception level is set to the initial level Lf.
(Step 4). If the value is smaller, the out-of-service area is notified in Step 14 until the value becomes larger, and this is repeated. If the mobile station moves and the reception level becomes higher than the initial level Lf, the process proceeds to step 5 and the ID of the base station is detected.

Normally, in the same area, the ID of the base station
Does not change, it is determined that they are the same in this branch, and the determination level LL stored in the level memory 4 is read (step 7). Then, at step 8, the reception level Lo
Is greater than or equal to the determination level LL, and if it is greater, the in-service notification is made; if it is smaller, out-of-service notification is made (steps 9 and 10). Then, the process returns to step 3 and repeats until the power is turned off.

However, the base station with which the mobile station communicates changes with the movement of the mobile station, and if the ID of the base station is different, the process branches from step 6 to step 11, where the location registration unit 7 and the RF
The location is registered in the ID memory 9 by wireless transmission / reception from the / IF unit 1.

Then, the communicability determination level L1 is extracted from the radio signal from the base station whose location has been registered (step 12), and the communicability determination level L1 is registered in the level memory 4 under the control of the location registration unit 7. (Step 13). Thereafter, the process proceeds to step 7, and the same is repeated.

By these series of operations, the information in the service area or outside the service area is reliably provided, and the user is not confused by notifying the service information and the service information at the same position.

[0040]

According to the present invention, even when a mobile station moves between different base stations having different communicable judgment levels for one paging area or a paging area constituted by a plurality of base stations, power-on or communication can be performed. When the mobile station moves from outside the service area to the service area, the area display (notification) according to the communication availability determination level of the new base station can be performed at any time without being limited to the communication availability determination level stored in the mobile station.

Further, when the base station is powered on or when the base station moves from outside the communication area to the service area, an erroneous display (notification) is temporarily made based on the communication enablement judgment level stored in the base station, and then the communication enablement judgment of the new base station is made. Depending on the level, it is possible to solve the problem of correct display (notification) and realize a display without a sense of incongruity.

[Brief description of the drawings]

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

FIG. 2 is a flowchart of an embodiment of the present invention.

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

FIG. 4 is a flowchart of a conventional example.

FIG. 5 is a diagram showing a communication area between a base station and a mobile station.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 RF / IF part 2 Reception level detection part 3 Level comparison part 4 Level memory 5 Notification part 6 Modulation / demodulation part 7 Location registration part 8 ID discrimination part 9 ID memory 10 Communication possible judgment level selection part 11 Initial level setting part

Claims (3)

(57) [Claims] 1. A mobile station, comprising: a plurality of base stations; and a mobile station capable of performing wireless communication with the base station within a service area where at least one of the plurality of base stations can be serviced; Identification signal transmitting means for transmitting an identification signal indicating the base station at least within a service area, and reception level transmission for transmitting reception field strength information indicating field strength for limiting a reception range preset by the base station Means, provided in the base station, reception level detecting means for detecting the electric field strength from the base station, the mobile station of the base station corresponding to which of the service area of the base station is present An identification memory stored as an identification signal, and an identification signal stored in the identification memory are compared with an identification signal from a receiving base station. Identification signal determining means for determining that the mobile station is located in a service area of a base station different from the service area of the recorded base station, and storing the received identification signal in the identification memory; and In the case of a negative output, the base station including the service area where the mobile station is located,
Position registration means for registering that the mobile station is located in the service area; level memory for storing received field strength information at the time of the last position registration; and reception from the base station for which position registration has been performed. Electric field intensity information and the received electric field intensity information already stored in the level memory are selected under the control of the position registration means,
A level selecting means for outputting, an output from the receiving level detecting means, a level comparing means for comparing an output from the level selecting means, and controlling a notifying means for notifying whether the service area is within or outside the service area based on the result. , Provided in the mobile station. 2. The level memory according to claim 1, wherein the level memory stores the received electric field strength information of the registered base station when the location registration means operates and the location registration processing is performed. Mobile communication system. 3. An initial level setting means for holding an initial level which can be set in advance and outputting the initial level to an input of the level selecting means, wherein when power is turned on or out of a service area, the level selecting means is provided. 3. The movement according to claim 1, wherein the initial level is selected, the level comparison unit compares the output with the output from the reception level detection unit, and the result is used to control the notification unit. Communications system.