JPH0336344B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides information on the location of a mobile station relative to a location registration station in a mobile communication system in which a service area consists of a plurality of location registration zones and a location registration station having a registration memory manages at least one location registration zone. Regarding registration method.

<Background> This type of mobile communication system is currently being put into practical use as a car phone system. That is, in the car telephone system, as shown in FIG. 1, a service area 1 is divided into a plurality of location registration zones 2a, 2b, 2c, .
a is divided into a plurality of wireless zones 3a, 3b, 3c..., and each wireless zone 3a, 3b, 3c...
are provided with base stations 4a, 4b, 4c, . . . , respectively. In the case of a mobile station terminating call, it is difficult to determine the terminating exchange where the mobile station 6 is located using only the selection number (mobile station number) dialed by the calling subscriber.
Therefore, one or more wireless zones are grouped together as a location registration zone, and each time a mobile station moves between location registration zones, the mobile station detects which location registration zone the mobile station is in. It is reported to the location registration station 5. The location registration station stores this information in its registration memory and manages which location registration zone each mobile station is in based on this information. This prevents invalid incoming call processing (such as calling a mobile station) to the registered zone.

Location registration at a mobile station has conventionally been performed as follows. For example, when the mobile station 6 is moving within the wireless zone 3a, the position transmitted from each base station is transmitted at fixed time intervals or when the reception level of the signal from the base station falls below a predetermined value. It sequentially receives control channels specific to the registration zone, determines that the mobile station exists in the location registration zone corresponding to the control channel with the highest reception level, and sends the determination result to the location registration station via the control channel. The location was registered by notifying the user along with the mobile station number.

In this way, the mobile station performs a location registration zone search at regular intervals, and therefore the mobile station moves within the wireless zone near the center of the location registration zone, rather than in the wireless zone at the border of the location registration zone, and immediately moves to the adjacent location registration zone. performs a location registration zone search at regular intervals even if there is no possibility of movement, and depending on radio wave propagation conditions, the control channel may be searched even if the user is moving in a wireless zone other than the wireless zone at the boundary of the location registration zone. The location registration zone search will be performed when the reception level becomes below a predetermined value. In other words, in the past, location registration zone searches were conducted in vain even when there was no possibility of immediate movement to an adjacent location registration zone. While the mobile station is searching for a location registration zone, it becomes impossible to receive calls to the mobile station, and it is particularly undesirable as a communication method that calls cannot be received because of the useless location registration zone search.

Furthermore, in the past, the location registration zone search was performed sequentially for the control channels of all location registration zones, and when there were a large number of location registration zones, the location registration zone search took a considerable amount of time. In other words, in the past, control channels of location registration zones other than the location registration zone adjacent to the location registration zone in which the mobile station is moving were also searched, resulting in a wasteful search.

<Summary of the invention> In the present invention, a control channel common to the wireless zone is provided for each location registration zone, and a dedicated control channel is provided for each wireless zone, and the wireless zone is controlled by using the control channel dedicated to that wireless zone. The base station notifies the mobile station whether or not it belongs to the boundary of the location registration zone, and the mobile station determines whether to perform a search for location registration based on this broadcast information. In other words, if this notification indicates that there is no location registration zone boundary, even if a location registration zone search request occurs, the search will not be performed. In this way, useless searches are stopped, and the number of lost calls is reduced accordingly.

Furthermore, since a mobile station only moves to an adjacent location registration zone, for each location registration zone or wireless zone, other location registration zones from which the mobile station may move are determined in advance. , the control channel to be searched is notified to the mobile station through a common control channel or a dedicated control channel, and the mobile station searches for the location registration zone only for the notified control channel, thereby reducing the location registration zone search time. This reduces the number of missed calls.

<Example> As shown in FIG. 1, each location registration zone 2a, 2
Common control channels fsa, fsb, fsc, etc. are assigned to wireless zones within each zone, and for example, in the location registration zone 2a, the base station 4a of each wireless zone 3a, 3b, 3c, etc. ,4b,
4c... is the assigned common control channel
Sending fsa. Additionally, each wireless zone is assigned a dedicated control channel. This is done, for example, by assigning time slots to each base station. That is, there is a time period in which a signal common to the entire location registration zone is transmitted as a common control signal (channel), and a different time period in which a dedicated control signal (channel) is transmitted for each wireless zone. For example, in the location registration zone 2a, these base stations 4a, 4b,
4c... is transmitted on the same frequency fsa. Additionally, measures are generally taken to prevent interference by matching the radio frequency and the phase of the modulated signal.

FIG. 2 shows an example of a control channel according to this time period. From the location registration station 5 to each base station 4a to 4c,
As shown in FIG. 2A, a synchronization signal 7, a common control channel 8, a control channel 9a dedicated to the wireless zone 3a, and a control channel 9 dedicated to the wireless zone 3b.
b. A dedicated control channel 9c is sequentially sent to the wireless zone 3c.

The control signal relay section in each base station 4a to 4c is configured as shown in FIG. 3, for example. The control signal shown in FIG. 2 from the location registration station 5 is supplied from a terminal 10 to a repeater 11 and a detector 12. The repeater 11 amplifies the control signal and outputs it to the output gate circuit 13.
and the detector 12 detects the synchronization signal 7 in the control signal.
is detected and the bit counter 14 is driven. The bit counter 14 counts each time slot of the control signal using the synchronization signal 7 as a reference, and the inside of the count is supplied to the gate signal generator 15. The gate signal generator 15 has a common control channel 8 with the synchronization signal 7.
It generates a gate signal to take out the control channel 9a of the time slot provided in advance in the base station, for example 4a, and uses these gate signals to control the gate circuit 13.
When opening the transmitter, turn on the transmitter from terminal 16.
Output as OFF control signal. Therefore, base station 4
In a, a synchronizing signal 7, a common control channel 8, and a dedicated control channel 9a are obtained at the output terminal 17 of the gate circuit 13 as shown in FIG. 2B, and these are transmitted. The base station 4b transmits the synchronization signal 7, the common control channel 8, and the dedicated control channel 9b as shown in FIG. 2C, and the base station 4c transmits the synchronization signal 7 as shown in FIG.
As shown in , a synchronization signal 7, a common control channel 8,
A dedicated control channel 9c is transmitted. In this way, each base station transmits a dedicated control channel in a time slot (time slot) previously assigned to that base station.

The common control channel 8, as shown in FIG.
It is composed of an information signal 21 common to a to 4b. Alternatively, this common control signal is composed of an incoming call signal 19 and a common information signal 21, as shown in FIG. 4B.

On the other hand, each dedicated control channel 9a to 9c corresponds to the common control channel 8 in FIG. 4A, and the wireless zone of the base station is located near the boundary of the location registration zone, as shown in FIG. 5A. It consists of a code 22 indicating whether or not a mobile station in the wireless zone performs a location registration zone search, and a control channel information signal 24 dedicated to the base station, for example 4a. If the common control channel 8 shown in FIG. 4B is used, dedicated control channels 9a-9
c is composed of a code 22 indicating whether or not to search as shown in FIG. 5B, a code 23 indicating p control channels to be searched by the mobile station, and a dedicated control channel information signal 24. .

A mobile station cannot move from its current location registration zone to any location registration zone other than its adjacent location registration zone at once. Therefore, the mobile station has the control channel of the location registration zone in which it is currently moving;
A location registration zone search can be performed by searching only the control channels of location registration zones adjacent to that zone. That is, the control channels to be searched are determined according to the location registration zone, and these control channels to be searched are transmitted with the code 20 in FIG. 4A. Similarly, once the wireless zone is determined, the control channel to be searched during the location registration zone search is determined, and the control channel is transmitted using the code 23 in FIG. 5B in accordance with each wireless zone.

If the mobile station 6 is located in the center of the location registration zone 2a and not near the border, such as the wireless zone 3a in FIG. Never. Therefore, in this way, code 2 transmitted from a base station in a wireless zone that is not near the boundary of the location registration zone.
2 indicates that the location registration zone search is unnecessary.

For example, as shown in FIG.
2 and a modulation transmitting section 37 are connected. The connection control unit 38 is connected to the reception demodulation unit 32, the modulation transmission unit 37, and the telephone 39, and controls the connection between these units.
Further, the reception channel control section 34 controls the synthesizer 36 based on the channel information obtained from the reception demodulation section 32, and controls the reception demodulation section 32, the modulation transmission section 37,
Configure channel settings for . A signal indicating the reception level from the reception demodulation section 32 is converted into a digital signal by the AD converter 38 and inputted to the reception channel control section 34 . This reception channel control unit 34 also performs a location registration zone search.

This location registration zone search is performed as shown in FIG. When the device is powered on, each part is initialized in step _S1 , and in step _S2 it is checked whether the all control channel searched flag _F1 is off, and if it is off, the process moves to step _S3 . The reception demodulator 32 is set to the control channel written first in the first memory. The reception level of the control channel is measured in step _S4 , and the measured level and the control channel are stored in the second memory in descending order of reception level in step _S5 . In step _S6 , it is checked whether the reception levels of all control channels in the first memory have been measured, and if the measurement has not been completed, the reception demodulator 32 is set to the next control channel in the first memory in step _S7 . Return to step _S4 .

When the reception level measurement of all control channels is completed in step _S6 , the all control channel search completed flag _F1 is turned on in step _S8 . Thereafter, in step _S9 , the reception demodulator 32 is set to the one with the highest reception level among the searched control channels. Next, in step _S10 , time slots corresponding to each radio zone in the control channel, that is, dedicated control channels 9a, 9b, 9c
, and determine the wireless zone corresponding to the maximum level. In step _S11 , it is checked whether a signal can be received on the set control channel. This is to confirm that there were no errors in the processing based on the reception level up to that point. If no signal is received in step _S11 , the non-reception flag _F2 is turned on in step _S12 and the process moves to step _S13 . In step S ₁₃ search flag
Check whether _F3 is on, that is, code 22 indicating whether or not to perform the search shown in Figure 5 indicates that a search will be performed.If the search flag _F3 is off, no search for location registration will be performed. Then move on to step _S14 .
If the non-reception flag _F2 is on, the all control channel search completed flag _F1 is turned off and the process returns to step _S2 .
Therefore, the process returns to step _S3 and the above-described process is performed again.

If a signal is received from the control channel with the maximum level set in step _S11 , it is checked in step _S15 whether code 22 in the dedicated control channel indicates that it should be searched, and if it is indicating that it should be searched. is the code 20 of the control channel to be searched indicated in the common control channel in step _S16 .
Alternatively, the code 23 of the control channel to be searched, which is indicated in the dedicated control channel, is written into the third memory and the process moves to step _S17 . Search flag F ₃ in step S ₁₅
If it is off, the process immediately moves to step _S17 to check if there is an incoming call, and if there is an incoming call, the incoming call is processed in step _S18 , and if there is no incoming call, the process returns to step _S11 .

On the other hand, if all control channels have been searched in step _S2 , the flag _F1 is on, and the process moves to steps _S19 and _S20 . In step _S19 , it is checked whether a certain period of time has elapsed, and when the certain period of time has elapsed, the process moves to step _S13.In step _S20 , it is checked whether the reception level has fallen below the set value, and if it has fallen below the set value, the process moves to step _S13 . Move to. If the search flag _F3 is off in step _S13 , a loop of step _S14 , step _S2 <step _S19, step _S20 > step _S13 is repeated without performing a search for location registration. Search flag in step S ₁₃
If _F3 is on, the process moves to step _S21 to determine the location registration zone, sets the reception demodulator 32 to the first control channel of the control channels to be searched previously stored in the _third memory, and then In step _S22 , the reception level of the control channel is measured, and in step _S23, the measurement result and the control channel are written in the _second memory in descending order of the reception level. In step _S24 , it is checked whether all the control channels written in the _third memory to be searched have been searched, and if all the searches have not been completed, in step _S25 , the next control channel in the _third memory is received. The demodulator 32 is set and the process returns to step _S22 . If all the control channels to be searched have been searched in step _S24 , the process moves to step _S9 .

When a signal is obtained from the control channel set in step _S11 and confirmed to be correct, the code indicating the control channel and the mobile station number are sent to the location registration station 5 through the base station.
Performs location registration of the mobile station.

<Effect> When the device power is turned on as described above, all control channels are searched, but after that, the search for determining the location registration zone is performed only when the search code 22 or search is instructed. and if this does not instruct a search, the search for determining the location registration zone will be performed even if a certain period of time for the conventional location registration zone search has elapsed, or if the reception level falls below the set value. do not have. Even if this search is not performed, the mobile station will not deviate from the current location registration zone, and there is no risk of hindering the mobile station's calls.Furthermore, since such unnecessary location registration zone searches are not performed, the mobile station can move as much as possible. There will be fewer missed calls to the station. In addition, when the device power is turned on, all control channels are searched, and only the control channels specified in the control channel that should be searched are searched, which shortens the search time. There will be less loss.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a mobile communication system to which the present invention is applied, Fig. 2 is a time chart showing an example of relaying common control signals in multiple wireless zones at a base station, and Fig. 3 is a diagram showing a common control signal at a base station. FIG. 4 is a block diagram showing an example of a control signal relay section; FIG. 4 is a diagram showing an example of the configuration of a common control signal in a base station; FIG.
FIG. 6 is a diagram showing an example of the structure of a control signal corresponding to each radio base station, FIG. 6 is a block diagram of main parts showing an embodiment of a mobile station, and FIG. 7 is a flowchart showing an example of operation in the mobile station. 1: Service area, 2: Location registration zone,
3: wireless zone, 4a to 4c: base station, 5: location registration station, 6: mobile station, 7: synchronization signal for synchronizing each base station, 8: information signal common to base stations,
9a to 9c: Dedicated control channel corresponding to each wireless zone 3a to 3c, 19: Incoming call signal, 20: Control channel code to be searched, 21: Information signal common to base stations, 22: Surrounding zone display signal (search code signal), 23: control channel code to be searched,
24: Information signal for each base station.

Claims (1)

[Claims] 1. In a mobile communication system in which a service area consists of a plurality of location registration zones, each location registration zone consists of at least one wireless zone, and a base station is installed in each wireless zone, As control channels for connection, a control channel common to each wireless zone within the location registration zone and a control channel dedicated to each wireless zone are provided, and it is determined whether the mobile station belongs to a wireless zone at the boundary of the location registration zone. The mobile station is characterized in that the base station notifies the mobile station of the location using a control channel dedicated to each wireless zone, and the mobile station determines whether or not to perform a search for location registration based on this broadcast information. Station location registration method. 2. When a mobile station belongs to a wireless zone at the boundary of a location registration zone and performs a search for location registration, the control channel to be searched by the mobile station is set to a control channel that is common to the wireless zones within the location registration zone to which the mobile station belongs. The mobile station position according to claim 1, characterized in that the base station broadcasts to the mobile station using a control channel, and the mobile station searches the control channel and registers the position according to this broadcast information. How to register. 3. When a mobile station belongs to a wireless zone at the boundary of a location registration zone and performs a search for location registration, the control channel to be searched by the mobile station is moved from the base station using a control channel dedicated to each wireless zone. 2. The mobile station location registration method according to claim 1, wherein the mobile station searches for a control channel and registers the location according to the broadcast information.